Structural Organization in Animals
Human body consists of 11 organ systems each composed of differing amounts of the following tissues. An organ
system is a complex mix of tissues that perform a specific task.
Cell is the basic unit of life
Tissue is a cooperative unit of cells that perform a specific task. Tissues differ in proteins that are expressed.
Organ is a cooperative unit of tissues that perform a specific task
Four major types of tissues:Epithelial, Connective, Muscle and Nervous
Epithelial: sheets of closely packed cells called “membranes” that
Covers the internal and external surfaces, i.e. epidermis (skin) and linings of organs; Forms barriers for entry and
exit; Forms glands by folding inward (exocrine and endocrine)
Basement membrane connects inner surfaces of epithelia to underlying tissues, composed of polysaccharide and
fibrous proteins.
Three types: Squamous, Cuboidal and Columnar
IDENTIFY AND DEFINE EACH
 Squamous:
simple squamous is one cell layer; is thin and leaky
(ie. blood vessels)
stratified is two or more cell layers thick; regenerats
rapids by mitosis; covers surfaces subject to abrasion
(lining of esophagus)
 Cuboidal and Columnar are large cells ; make
secretory products; form folded surfaces (lines
digestive tract forms moist epithelium and mucous
membrane of lungs) hair like projections pushes
dust, pollen particles out.
CONNECTIVE TISSUE: sparce population of cells scattered through an extracellular matrix. The matrix which is
a web of fibers embedded in substances that are liquid  solid, all produced by the cell.
Six types:
Loose CT(CT, most common), assists in holding organs in
place and binding tissues to other tissues(dermis: nourishes
the dermal tissues)
Adipose CT is composed of fat: pads, insulates, energy
storage
Blood is fluid CT. Composed of formed elements and
plasma. Plasma is the fluid matrix composed of salts and
proteins (i.e. antibodies). Formed elements composed of three
types of cells (erythrocytes (rbc), leukocytes (wbc) and
platelets (cell fragments, specializing in clotting). Blood
vessels transport blood which caries dissolved O2 and
nutrients to cells and removes CO2 and cellular wastes.
RBC transports O2; WBC carry immune cells
Fibrous CT the matrix is dense and contains fibers: includes
tendons (connects muscle to bone) and ligaments (connects
bone to bone)
Cartilage CT forms strong, flexible (resists shattering)
skeletal material, made of collagen fiber rolled in a rubbery
substance. Round ends of bones, forms cushioning discs
between vertebrae, support of noses and ears
Bone is rigid and flexible connective tissue. Matrix of
collagen embedded in calcium salts. Like all other tissues
bone is nourished by component delivered in blood. Blood
vessels enter bone through canals.
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Nervous: Forms the communication network, specialized in conduction of electrical impulses. Two types of cells:
NEURON AND NEUROGLIA CELLS
 Neurons:conduct the sensory input electrically. .
Three parts:
Motor Neuron
1. dendrites & cell body
(sensing end)
2. axon (elongated region,
conducting end)
3. synapse (point of junction,
neurotransmitters
accumulate)

Neuroganglia aka glia: protects the neuron with nutrients and insulation.
Neurons can be either affector (sensing), or effector (responding) and interneurons. Involved in homeostasis
(maintaining a dynamic equilibrium) using positive and negative feedback mechanisms constantly monitoring
internal and external temperatures, moisture, pressure and nutrient content of cells.
Muscular: special ability to shorten (contract) using two proteins (actin and myosin). Function in movement. Work
in antagonistic pairs. A muscle is a bundle of long cells called fibers. Three types vary in arrangement of the actin
and myosin proteins: Skeletal: Cardiac: Smooth.
CHARACTERISTIC OF THE THREE TYPES OF MUSCLES
Skeletal Muscles are striated, voluntary, non branced and are found associated with the skeletal system.
More about them below.
Smooth Muscle: Causes slow, steady, strong, involuntary movements in intestine, air passageways in lungs
and other hollow organs. THEY ARE NON STRIATED AND INVOLUNTARY
Smooth muscle is found in the walls of all tubes this includes blood vessels, digestive organs, windbipe, uterus.
Smooth muscles are involuntary, non striated and contract in a wave like motion called “peristalsis”.
Cardiac Muscle: cause involuntary contractions of the heart. Cells are striated and branched, found only in
the heart.
Cardiac muscle is striated like skeletal muscle which means that it has microscopically visible myofilaments
arranged in parallel with the sarcomere structure described above. The striations elongate when relaxed and shorten
when contracted. When one cell is excited the resultant action potential is spread through the interconnections. This
is an important feature in that it allows the atrial or ventricular muscle to contract as one to forcefully pump blood.
Homeostasis is to maintain a constant internal environment. This is done using two types of feedback
mechanisms:
Negative Feedback:is a feedback in which the system responds in the opposite direction as the
perturbation, resulting in a decrease in the original signal.
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Positive Feedback:is
a feedback in which the system responds in the same direction
as the perturbation, resulting in amplification of the original signal instead of
stabilizing the signal. Organ system 1: Reproductive System
Human development begins with fertilization of 2 haploid cells (sperm and egg) to produce 1 diploid cell –
zygote.
Gametes are produced by meiosis (reduction division) in the sex organs called gonads (ovaries and testes).
Gamete production is control by hormones produced in the pituitary glands and in regions of the gonads.
Sperm production occurs continuously within the seminiferous tubules in the testes. Sperm and androgen
production are under the control of the FSH and LH produced in the pituitary gland in the brain. FSH increases
production of sperm by testes. LH promotes secretion testosterone.
Testosterone is produced by the interstitial cells scattered between the seminiferous tubules in the testes.
Testosterone has numerous effects, promotes maturation and development of accessory sex organs, proliferation of
body hair, thickening of the skin, enlargement of the larynx, increased glandular secretions (sweat and body odor),
increased metabolic rate and male patterned baldness.
Spermatozoan are produced immature (without flagella and a head) by meiosis then travel travels to the epididymis
and matures.
Sperm cells are small and packed with mitochondria (energy) and consist of a nucleus, flagellum and a head
“acrosome” essentially a lysosome (contains hydrolytic enzymes that digest the cervical mucus and the protective
coating around the egg).
Testes descend from the body cavity into the scrotum during the ninth month of fetal life.
Male Sexual Response
Penis erection is accomplished by blood flowing into the spongy erectile tissues
During ejaculation sperm travels through the vas deferens over the bladder
Through the seminal vesicles, prostate gland and bulbourethral gland. The peak in sexual arousal promotes
muscle contraction of these organs. As it travels it picks up a milky alkaline fluid, fructose and a mucoid
secretion. The vas deferens joins the urethra. Sperm plus secretion make semen typically >300 million sperm/
ejaculation (fertile males) and <100 million (infertile)
Female System: Oocytes in women are stored in the ovaries nurtured in a complex of cells and fluids called
follicles. At birth she has produced 40,000 and 400,000 follicles. Once a month, every 28 days, she ovulates :the
oocytes mature into an egg and travels down the uterine tube (aka fallopian). During her reproductive years she will
use only a few hundred of these follicles. Oogenesis is the process by which and egg is made from a germ cell.
Meiosis produces 3 polar bodies and 1 egg cell.
FSH stimulates follicle maturation to produce egg cell
LH stimulates the release of the egg from the ovary and stimulates the secretion of estrogen and progesterone to
prepare the endomedrium lining for the embryo
Menstral Cycle:
Day 1-7: Bleeding (low estrogen and progesterone) due to breakdown of endometrium
Day7-14: Following bleeding: Low EST and PRO signals pituitary to secrete FSH and LH Stimulate several
follicles; Follicles secrete estrogen which causes regrowth of the endometrium.
Day 14: ovulation. Egg release. Due to surge in LH, ruptures dominant follicle. Remaining follicle develops into
corpus luteum secreting PRO and EST. Endomedrium prepared for fertilization and implantation . Lining secretes
EST and Pro
If fertilization and implantation does not occurs, the corpus luteum disintegrates. EST and PRO levels increase and
new ovarian cycle is initiated.
Fertilization  EST and PRO remain high. Corpus luteum is maintained eventually replaced by the placenta. High
EST and Pro inhibit pituitary FSH and LH.
Organ system 2: Integumentary System
Functions: protection, sensing, controls evaporation of body fluids and heat loss.
Includes skin (epidermal (composed of epithelial cells)and dermal layer), exocrine glands are embedded in these
layers, hair follicles and associated glands and nails, nerve fibers and associated touch and pressure receptors
Several exocrine glands that excrete salt water, oils and milk
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Organ system 3: Skeletal system
The human body is made up of over 200 bones of different shapes and sizes. Bones have living cells (called
osteocytes) bound together by a hard, calcium-like material. This makes the bone strong and rigid. The bones are
hollow and filled with a spongy material, called marrow. Red and Yellow Marrow.
All blood cells are made in the red bone marrow of long bones.
The bones have several important functions.

The skeleton gives the body rigid support and the joints act as
levers so that the body can move.

They protect organs in the body; for example, the ribcage
protects the heart and lungs.

The bones also store some of the body's essential minerals,
especially calcium.

Produces the blood cells in marrow
The joints of the bones are covered in cartilage - a tough, flexible
material, rather like gristle. As cartilage is more elastic than bone it
allows the bones to move freely at the joints. It also cushions the bones
at the joints to stop them rubbing against each other.
Marrow produces three different types of blood cells:

Red blood cells which carry oxygen to all cells in the body

White blood cells which are essential for fighting infection
 Platelets which help the blood to clot and prevent bleeding
Stem cells are blood cells at the earliest stage of development in the bone marrow. They develop into the different
blood cells described above. They can be taken from the bone marrow or collected from the bloodstream
Bones are made of two different types of bony tissue.
1. Compact bone is smooth, hard material that covers the
surface of bones. It is thickest around the shaft of the bone.
2. Spongy bone has small spaces and is more brittle than
compact bone. It is found at the ends of bones under a layer
of compact bone.
Three types of cells work together in bone regeneration: osteoblasts, osteocytes, osteoclasts.
1.
2.
3.
The osteon is the fundamental unit of the bone . Osteon Structural unit of compact bone. Composed of
concentric bone lamellae with osteocytes located in between.
Osteoblast building cells aid the growth and development of teeth and bones. It secretes the ground matrix
rich in collagen and embedded in calcium and phosphorous. Ca and P are minerals derived from blood.
Bone forming activity is “Osteoblast” and increases when blood Ca and P levels increase. Ca and P
increase bone density
Osteoclast is 0bone absorbing activity this is essentially breakdown of bone. Low blood Ca causes bone
reabsorption/breakdown. Osteoporosis occurs when osteoclast cells reabsorb bone faster than the
osteoblast cells are building it.
The bones of the skeleton and muscles interact to produce movement
Tendons: are connective tissue that join muscle to bone.
Ligaments are connective tissue that join bone to bone.
Muscular System includes all of the skeletal muscles under voluntary control. There are 630 muscles in the human
body.
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40% of the body is skeletal muscle. Skeletal muscles are striated, non-branching under voluntary control.
5-10 % of the body is cardiac and smooth muscle. Cardiac and smooth muscle are not a part of the
muscular system, under involuntary control.
Functions of Muscles:
 maintain balance and posture
 provide heat as a result of the muscle contraction.
Muscles are organs in that they contain a variety of tissues, connective, nervous and skeletal muscle.
Muscle fibers come together at the ends to form tendons that attach to bone. Each muscle has within it a
number of fascicles (oval shaped bundles). Inside each fascicle is a long muscle cell called a fiber, each is the
length of the muscle and is multinucleated. Because Muscle cells are elongated they are called fibers.
Inside the fibers are myofibrils (more long thin structures).
The components of muscle:
Myofibril  Fiber Fascicle  Muscle
Each myofibril is composed of contracting units called
sarcomeres, joined end to end at Z-lines.
Each sarcomere is composed of thick filaments,
containing mostly myosin surrounded by 2 thin
filaments composed largely of actin filaments but also
tropomyosin and troponin.
This is one myofibril with about 4.5 sarcomeres
shown
The sarcomere is the functional unit of muscles.
Thick myosin filaments lie in the middle of the
sarcomere and thin filaments are attach to either end of
the sarcomere.
During contraction, thin filaments slide towards each other to the center of the sarcomere . In other words the
sarcomere shortens.
Ca is released allows the myosin heads to attach to the actin (thin) filaments. When the heads pivit. The Thin
filaments move closer together. Shortening the muscle cells via the sarcomere.
Contraction of a Muscle requires an Action potential and is signaled by an excited Neuron
Contraction in skeletal muscle begins with an action potential in the muscle fiber. This causes the release of calcium
from the sacroplasmic reticulum. The action potential in the muscle fiber begins after it is excited by an excited
neuron. An action potential is an electrical change across a cell membrane due to changes in the conduction of ions
across the membrane.
Cellular energy, ATP, is needed to releases the head from the actin filament and cocks the sarcomere for the
next ratchet power stroke.
Energy is retrieved from foods and stored substances via Cell Respiration.

Sources of high energy phosphates :phosphorylcreatine and ATP
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
Fermentation or Anaerobic Respiration: When oxygen supplies are inadequate lactic acid builds up in the
muscle. An oxygen debt exists. Oxygen is used to convert the lactate into carbon dioxide and water and
replenish energy stores.
Muscle Fatigue: Prolonged strong contractions leads to fatigue of the muscle caused by the lack of adequate
supplies to maintain the work load.
Hypertrophy is an increase in muscle mass caused by forceful muscular activity. The diameters of individual fibers
increase, nutrient and metabolic substances increase, mitochondria may increase, and the myofibrils also increase
in size and number. Muscular hypertrophy increases the power for muscle contraction and nutritive mechanisms for
motioning that increased power.
Atrophy results when a muscle is not used for a length of time or is used for only weak contractions. As little as one
month of disuse can sometimes decrease the muscle size to one half normal. Damage to the nerve to a muscle results
atrophy a well. If the damage is repaired in the first 3-4 months the muscle will regain full function. After four
months muscle fibers will have degenerated to fibrous and fatty tissue.
Duchenne muscular dystrophy is an X-linked gene disorder that makes a non functional protein called
dystrophin. Age at onset: two to six years; symptoms include general muscle weakness and wasting; affects pelvis,
upper arms, and upper legs. The exact function of dystrophin is unknow by is involved in Ca handling in muscle
cells.
The Nervous System
Components: Brain, Spine and Nerves
Functions
1. Sensory Input:Conduction of signals from sensory organs (eyes, ears, nose, skin, etc.) to information
processing centers (brain and spinal cord).
2. Integration:Interpretation of sensory signals and development of a response. Occurs in brain and spinal
cord.
3. Motor Output:Conduction of signals from brain or spinal cord to effector organs (muscles or glands).
Controls the activity of muscles and glands, and allows the animal to respond to its environment.
Components of Nervous System : brain, spinal cord and peripheral nerves.
Two main divisions:
Central Nervous System, CNS , it includes the brain and in vertebrates, spinal
cord.
Peripheral Nervous System, PNS, peripheral, nervous systems. Includes
Affector and Effector Neurons. The PNS carries information either from the
sensory receptors to the CNS (affector) or from the CNS to a muscle, gland or
another neuron (effectors.
Nerves are made of bundles of neurons and neuroglial cells.
Neurons are cells with an elongated region called an axon, and numerous
membrane extensions from the cell body called dendrites.
In humans, neurons can grow up to a meter long. All the functions of the
nervous system involve neurons communicating either with one another, or
with cells of other types.
Three types of neurons
Sensory Neurons, sense conditions both inside and outside the body including touch, temperature and pressure and
sight, smell, hearing and taste. They carry information from the sensory receptors to the CNS.
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Interneurons are located only in the brain and spinal cord. They are responsible for analysis, integration or
processing of sensory inputs and coordination of motor output. The CNS consists of the brain and spinal cord, they
are responsible for integrating and coordinating sensory data and issuing action or motor commands.
Motor neurons carry signals from the CNS to effectors, such as skeletal muscles or gland cells. Effectors
responding to the signal usually with a motor output
Sensory Neurons   
Interneurons
   Motor Neurons
Cells of Nervous Tissue
1. Neuron: Nerve cell. Structural and functional
unit of nervous tissue. Carry signals from one part
of the body to another. Note the three parts of the
neuron: Dendrite, Axon and Synapse
2. Supporting cells: Nourish, protect, and insulate
neurons. There are roughly 50 supporting cells for
every neuron. On this figure they are the Schwann
cells.
In humans, Schwann cells wrap around the
axons of neurons, forming a myelin sheath that
is essential for transmission of nerve impulses.
The Neuron’s Composition
The Cell Body houses the nucleus and most of the organelles
Dendrites are short numerous, highly branched extensions that convey signals toward the cell body
Axons are long and unbranched; they convey signals away from the cell body toward other neurons or effectors
Synaptic Knob located at the end of axons, they relay the signal
Communication between nerve cells is a result of changes in the electrical properties of the neuron’s outer
lining or plasma membrane.
The dendrites are the sensing branches of the neuron. They are either Polarized, Depolarized or Repolarized.
Polarized: Neuron has a Resting Potential . It is neg inside and positive outside. Sensing causes a cell at
resting potential to go to action potential. A resting nerve cell has a negative charge inside relative to outside (inside
-70mV).
Depolarized Neuron has an Action Potential . When a stimulus is applied to a nerve cell Na +2 is pumped
inside the axon of the nerve cell, the action potential is triggered in the axon by stimulus received by the dendrite.
The action potential is a localized electrical event. The electrical signal change moves down the axpn of a neuron,
like a domino affect. The action potential is transferred from cell to cell via a synapse.
Repolarized Neuron will return to Resting Potential: When Na+ channels close K+ channels open, K+
rushes inside. The cell returns to its resting potential.
At the synapse the electrical potential is converted to a chemical signal. The chemical signal is a
neurotransmitter molecule. Neurotransmitters promote changes in the cells capable of producing desired effects.
(release of digestive enzymes, insulin, affect Ca +2 stores). The signal is eventually transferred to the central nervous
system (brain and spinal cord) for processing. With processing a decision must be made, which part of the body will
be involved.
Neurotransmitters
 Acetylcholine: slows heart rate causes muscle cells to contract.
 Epinephrine, norepinephrine (increases heart rate)
 Serotonin (affect sleep, mood, attention and learning) When seratonin are low, you are at a higher risk of
developing mood-related medical problems.
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
When your body experiences stress, it releases neurotransmitters in response to the
stress. The more stress, the more neurotransmitters are released. Extreme cases,
you can deplete your store of neurotransmitters. Many antidepressant drugs are
serotonin reuptake inhibitors.
Dopamine affects pleasure.
What is Parkinson's disease?
Parkinson's disease is a slowly progressing, degenerative disease that is usually associated with the
following symptoms, all of which result from the loss of dopamine-producing brain cells: tremor or
trembling of the arms, jaw, legs, and face
The Brain is the master control center, directing output through the spinal cord and including homeostatic centers,
sensory centers and centers of emotions and intellect. Information is carried to and from the brain by the cranial
nerve and to and from the spinal cord by the spinal nerve. In the interiors of the brain is a hollow space filled with
fluid called the cerebrospinal fluid. Neurons in the brain are surrounded by myelin.
Myelin is the fatty covering that insulates nerve cell fibers in the brain and spinal cord to assist the high-speed
transmission of electrochemical messages between the brain, the spinal cord, and the rest of the body. When myelin
is damaged, transmission of messages may be slowed or blocked completely.
The peripheral nervous system forms a vast intercommunicating network. Motor neurons are either under
voluntary control (somatic system carrying messages to skeletal muscles) or out of conscious control (autonomic
system carrying messages to glands and smooth muscles.
The autonomic system is either SYMPATHETIC or PARASYMPATHETIC. The two components act to
regulate the internal environment.
Parasympathetic division is associated with REST AND REPOSE it prepares the body for digesting food
and resting, activities that gain and conserve the body’s energy supply. Including stimulation of all digestive
processes and slowing the heart and breathing rates.
Sympathetic division is associated with FIGHT OR FLIGHT. It prepares the body for intense, energyconsuming activities. Included is inhibition of digestion, increasing the heart and breathing rates, stimulation of liver
to release glucose and adrenal glands to release the fight or flight hormones (epinephrine and norepinephrine).
.
Brain
The adult brain weighs 1.3 to 1.4 kg (approximately 3 pounds).
The brain contains about 100 billion neurons and trillons of "support cells"
The Three Lobes of the Brain (HIND-, MID- AND FOREBRAIN)
Hindbrain: includes the Brain Stem and Cerebellum
1.
2.
The brain stem is the area of the brain between the thalamus and spinal cord and includes the medulla,
pons and reticular formation.. Functions of the Brain stem :Involved in involuntary activities such as
Breathing, Heart Rate and Blood Pressure
The cerebellum "little brain." is located behind the brain stem regulates coordinated muscle movements
Midbrain & Hindbrain form the brain stem
Function:integrates auditory information, coordinates visual reflexes and relays sensory data as well as Eye and
Body Movement
Forebrain: includes Thalamus, Hypothalamus, Pituitary Gland, Cerebral Hemispheres and Limbic System
Functions: site of most sophisticated integration
 Thalamus: Contains cell bodies or neurons and relays information to the cerebral cortex. It receives
sensory information and relays it and vice versa.
 Hypothalamus: Regulates homeostasis, i.e. controls hormonal output of the pituitary gland. It controls the
pituitary gland, body temperature, blood pressure, hunger, thirst, biorhythms, sexual urges, emotions.
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

Limbic System: is a group of structures that includes the amygdala, the hippocampus. These areas are
important for controlling the emotional response to a given situation.
o The hippocampus is also important for learning and memory
o The amygdala is the seat of emotion
The cerebrum has two hemispheres that divides it into left and right halves. Each hemisphere
communicates with the other through the corpus callosum, a bundle of nerve fibers.
The rational left (logic and mathematical ability)
The intuitive right (imagination, special perceptions artistic ability and emotions)
The four lobes of the cerebral hemispheres do specific tasks
Rich bed of neurons and synapses. It produces reasoning, language, imagination, artistic talent and personality
1. Temporal lobe: smell, hearing, auditory association
2. Frontal lobe: speech
3. Parietal lobe: speech, taste, reading
4. Occipital lobe: vision
The basal ganglia are a group of structures important in coordinating movement.
Endocrine System
Endocrine System is involved in sending signals to the body. It consists of more than a dozen endocrine glands
which secrete hormones into blood not into ducts.
The endocrine system controls whole-body activities such as Metabolic Rate, Growth, Maturation and
Reproduction. These hormones are secreted into the blood different from exocrine glands that secrete into body
cavities (the GI tract). The endocrine and nervous systems are closely associated.
Functions of Glands:
 Produce Steroid hormones that are lipid based and Non-Steroid hormones that are amino acid based. Most
glands produce amino acid based hormones. Steroid hormones are produced by the sex glands (testes and
ovaries) and the adrenal cortex.
 Secrete hormones and enzymes that regulate activities in cells. Hormones are chemicals signals that
coordinate body function. They have a controlling effect on specific target cell in other parts of the body.
List of Endocrine Glands
Hypothalamus (in the brain), is the master control center.
1. It receives information from the nerves about internal and external conditions.
2. It signals the pituitary gland when to secrete hormones using inhibiting and releasing factors. i.e. the hormone
oxitocin, induces contraction of the uterine muscle is secreted by the pituitary gland and is regulated by releasing
hormones.
3. It stimulates the medulla of the adrenal gland
Pituitary Gland located in the brain, also produces growth hormones and endorphins (the body’s natural
painkillers). The release of the sex hormones is controlled by hormone in the hypothalamus and pituitary glands
(FSH and LH). Two lobes of pituitary:
Anterior lobe produces
a. adrenocorticotropic hormone (ACTH),
b. Thyroid stimulating hormone (TSH)
c. growth hormones which promote enlargement of body parts,
d. prolactin (PRL) promotes milk production
e. follicle stimulating hormone and leutinizing hormone
Posterior lobe releases hormones made by the hypothalamus
a. antidiuretic hormone (ADH) promotes water retention
b. oxytocin (prostate gland in males and Stimulates Uterine contractions in women during labor and
mammary secretions.
Pineal Gland links environmental light conditions with activities that show daily or seasonal rhythms. It cues
reproductive activity and sleep patterns. It secretes malatonin.
Thyroid and Parathyroid regulates development and metabolism: located in the throat.
Thyroid Gland Produces two hormones, thyroxine and calcitonin. Their functions in homeostasis.
Thyroxine controls metabolic rate and early development of bone and nerve cells. It maintains normal
blood pressure, heart rate, muscle tone , and digestive and reproductive functions “metabolic rate”.
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Calcitonin lowers blood Ca+2. Stimulates Osteoblast activity Calcitonin (hormone) affects Ca+2 levels by
affecting its distribution in a) bones b) uptake in intestines and c) uptake in kidneys.
Parathyroid Gland produces Parathyroid hormones raise blood Ca+2. Stimulates Osteoclast. The is the
opposite of calcitonin.
The thyroid also regulates the amount of calcium in cells. Calcium is involved in blot clotting, transport of
molecules across membranes, muscle contractions and more.
Thymus produces the hormone thymosin involved in development of the immune system and the formation of B
cells
Adrenal glands mobilize responses to stress. (located on top of each kidney). It releases epinephrine and
norepinephrine into the bloodstream.
Epinephrine (adrenalin) dilates blood vessels in the brain and skeletal muscles but constricts vessels
elsewhere (directing blood to critical areas) Increases in Epinephrine increase the fight or flight response.
See nervous system, Autonomic response.
Nor-epinephrine (nor-adrenaline) produced in response to positive emotions-extreme pleasure.
Both Epinephrine and norepinephrine hormones stimulate
1) the liver to secrete glucose needed to make energy for fuel
2) increase blood pressure, breathing rate and metabolic rate and change blood flow patterns.
Pancreatic hormones manage cellular fuel found near the stomach: involved in digestion, secretion of
digestive enzymes, and Insulin (hormone) that lowers the levels of glucose and glucogon that raises the
level of glucose by releasing the stores of glycogen.
Insulin and Glucogon are antagonistic hormones, meaning they have the opposite response.
Insulin stimulates all body cells to take more glucose from blood. Most glucose is converted to glycogen, by the
liver. Glucose in Muscle cells is metabolized into energy, stored fats and proteins (Cellular Respiration) .
Deficiencies in insulin lead to high blood sugar, and diabetes.
Glucogon stimulates the liver to convert glycogen to glucose or fatty acids and amino acids to glucose, when
blood glucose levels fall as during a fast or during rigorous exercise.
The gonads secrete sex hormones (know about FSH, LH, Estrogen, Progesterone and Testosterone)
Sex glands make sex hormones (androgen, estrogen and progesterone) supporting egg and sperm formation,
maintains male and female secondary characteristics. All three are found in male and female. Females have a higher
ratio of estrogen to testosterone. Males have a high ratio of androgens (testosterone) to estrogen. The production of
these hormones is regulated by the release of FSH and LH from the pituitary gland. Estrogen prepares the uterus
for the embryo. FSH causes an egg to develop in a female and stimulates sperm production in a male. LH stimulates
the release of the egg from the ovary into the fallopian tube in females. This occurs every month and is called
ovulation. Testosterone is necessary for the production of sperm and for the male sex response.
Estrogen stimulates the development and maintenance of female reproductive system and secondary sex
characteristics (smaller body size, higher voice, breasts and wider hips). Progestin and Estrogen prepare the
uterus to support the developing embryo.
Disorders or Diseases Of Endocrine System
Hyperthyroidism caused by an excess of these three hormones in the blood, causes the individual to overheat,
sweat profusely, become irritable, develop high blood pressure and loose weight.
Hypothyroidism caused by an inactive thyroid gland. Individuals are cold, gain weight and are lethargic.
Deficiencies in iodine cause the thyroid to enlarge into what is called a goiter these individual have hypothyroidism.
Diabetes mellitus, is a hormonal disease involving insulin. Individuals cannot absorb glucose from the blood. It
occurs when there is not enough insulin or when body cells do not respond to insulin. The cells do not use glucose
and begin using fats and proteins. The body continues to accumulate glucose during digestion eventually glucose
accumulates and ultimately is detectable in urine. Insulin supplements or special diets with minimum carbohydrates
are the usual treatments.
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Hypoglycemia, in contrast, individuals who are produce too much insulin causing blood glucose levels to drop
severely below 70mg/100ml. Individuals become weak, hungry, sweating and nervous eventually convulsions may
develop. Individuals should eat more frequently.
Immune System and Response
Lymphatic or Immune System is a part of the defense function. . Functions:
a) To fight infections. Fluid enters the lymph system through open lymphatic capillaries. As it circulates
through lymph organs microbes and cancer cells are phagocytized
b) To return excess fluid from the interstitial fluid to the circulatory system. The lymph empties into the
circulatory system.
Individuals in good cardiovascular health with good dietary practices have stronger immune systems, and are less
likely to become ill.
Components of Lymphatic System.A network of lymphatic vessels,
lymph nodes and leucocytes (white blood cells)
1. Vessels: open vessel system that collects extracellular fluid and deliver it
as lymph to the blood vessels of the cardiovascular system. While in the
lymphatic system it is checked for infection.
2. Lymph nodes are concentrated areas of branched ducts containing large
numbers of lymphocytes (B cells and T cells) and macrophages. During an
infection these areas become activated and swell, causing tenderness and
aches and pains associated with a systemic infection.
3. Lymph organs or glands include the thymus, tonsils, appendix, spleen
and bone marrow
 Thymus gland using hormone, thymosin, stimulates development
of white blood cells (lymphocytes) in early life, specifically Tcells.
 Tonsils, spleen and bone marrow produce B-cells
Leucocytes (wbc) have a variety of functions. Certain white blood cells are
required to make these antibodies, T cells, B cells, neutrophil and
macrophage.
Two types of responses:
1. Non-specific defense does not distinguish between infectious agents and involves
 maintaining a physical barrier to the organisms involves:
- the epithelium is tightly packed and has
- keratin protein that acts as waterproofing, hairs
- glandular secretions prevent scraping
- sweat washes away microorganisms
- cells produce mucus, acids
- urine flush passageways
 White blood cells attack invading organisms and turn on the inflammation response. :
- phagocytes remove pathogens by cell-eating.
- natural killer cells survey tissue for normal and abnormal cell. An abnormal cell (cancer cell) when
detected is bombarded with a protein that causes cell lysis.
- mast cells stimulate the inflammation response.
 Chemical Warfare during non-specific defense
-Interferon proteins are antiviral compounds that interfere with replication
-Complement protein activation, enhances phagocytosis, destroys the membranes of invading cells and
promotes inflammation.
-Histamine and heparin proteins promote inflammation to create or repair a barrier, slowing the spread of
pathogens. They increase blood flow causing swelling, redness, heat and pain.
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-Fever is regulated by nerve cells in the hypothalamus. Infections, invasions reset the thermostat. High
body temperature speeds up the activities of the immune system. Prolonged high fevers disrupt or damage organ
systems.
3.
Specific defense protects against one type of infection. Involves several T cells, and B cells.
B-cells make antibodies to antigen. Four T-cells cytotoxic T, helper T, suppressor T and APC
It involves the antigen-antibody response that creates a type of memory. Antibodies are created by immune system
in response to an antigen. An antigen is any foreign substance that can elicit the production of antibodies. The
specific response is more effective. It is characterized by specificity, memory and prompt response to an
antigen.
It involves antigen/antibody binding
An Antigen is any molecule that elicits an Antibody response. In terms of pathogens these molecules are on the
surfaces of viruses, bacteria or fungi (molds). Often they are proteins but can be other molecules.
An antibody is produced specific to the antigen. The antigen remains in the system (blood and lymphatic system).
On a second invasion, the antibody recognizes the antigen.The 2nd response is quicker and more powerful.
Two Types of Specific Responses involving B or T lymphocytes
1. Humoral Response. Substances from cells are released into the blood
Lymphocytes are also derived from stem cells in the bone marrow. They include:
B cells, involves the humoral response, carry the antibody to the plasma, cells or interstitial fluids. B cell
have antigen receptors (antibodies) attached to their outer surfaces. Upon invasion by pathogen, they bind
to the antigen. They are then stimulated to proliferate. Now, all of these identical effector cells secrete
specific antibodies.
Once antibody/antigen binding occurs there is precipitation out of solution and attack by
phagocytes or activation of complement proteins that lyse invaders.
2. Cell Mediated Response
T cells, involved in cell mediated response, travel inside bloodstream. There are several types of T cells.
Killer T-Cells (Cytotoxic T-cells, CTL, recognize and attack pathogen-infected cells and are the only T
cells that kill.
Helper T (T4 or CD4) cells must be activated. Once activated they secrete interleukin proteins to promote
an immune response. For example the secretion of interleukin-2 amplifies both the humoral and cell-mediated
response, bringing into play B-cells.
Supressor T-Cells (T8 or CD*) suppress the activity of other lymphocytes so they don’t destroy normal
tissue
APC= antigen presenting cells: these cells ingest a microbe and display both a self-protein/foreign antigen
on its surface. Helper T-cells bind to this complex and are as a result activated to produce interleukin-2 and
stimulate the production of cytotoxic T cells and B-cells (humoral response). These cells destroy the foreign cell.
Overall: Our cells have fingerprints and the immune system depends on recognizing the fingerprints. It has to
distinguish “self from non-self”. It is the proteins that are on the plasma membrane that determine self. These
proteins are inherited in the genes. Therefore, only identical twins can have identical set of self-proteins.
Organ transplants are rejected because of the differences in self-proteins. Organ rejection is minimized by finding
a donor with matching self-proteins and/or using drugs that suppress the immune response. You can imagine the
other complications caused by suppressing the immune response.
Disorders of the Immune System
1.
Autoimmune diseases the immune system turns against its own body cells (rheumatoid arthritis, insulin
dependent diabetes, Crohn’s, lupus) Autoimmune diseases can each affect the body in different ways. For instance,
the autoimmune reaction is directed against the brain in multiple sclerosis or the gut in Crohn's disease or
destruction of insulin-, producing cells of the pancreas in Type 1 diabetes mellitus. In other diseases, such as
systemic lupus erythematosus (lupus), affected tissues and organs may vary among individuals with the same
disease.
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2.
Allergens elicit the production of antibodies. These antibodies promote the production of histamine.
Histamines are produced in amounts greater than normal causing symptoms like nasal irritation, itchiness and tears.
Antihistamines interfere with histamine action and give temporary relief. Excessive release of histamines can cause
anaphylactic shock which can lead to death.
3.
AIDS is caused by HIV a RNA virus. HIV attacks T-helper cells destroying the humoral and cell-mediated
immunity. Currently treatment with the triple cocktail postpones the development of AIDS. New approaches to
treatment include injecting patients with HIV-resistant stem cells and the development of a vaccine.
Concerning AIDS due to HIV infections, helper-T-cell count is most important.
A blood test showing the number of T4 cells you have tells you how health your immune system is especially for
AIDS and when to start taking the medications. T4 cells are the main target of HIV. Normal T4 count is between
500 and 1500 cells/mm3. Individuals with AID show a drop of 50 to 100 cells per year. T4 below 200 allows for
opportunistic infections (Pneumocystis carinii pneumonia). Individuals with T4 counts around this level should
begin prophylactic treatments (prevents opportunistic infections). T4 counts 350 and lower are a good time to start
the anti-Hiv therapies.
4. SCID severe compromised immunodeficiency syndrome (boy in the bubble)
Cardiovascular (Circulatory) System
Cardiovascular System includes the heart, blood and blood vessels. It includes bone marrow where red
blood cells are formed. It functions in transport of nutrients, dissolved gases and hormones to tissues throughout the
body and removal of waste from tissues to areas of filtration (kidneys).
Components of the Circulatory System: Heart, Vessels and Blood.
1. The heart is an organ about the size of the fist, that pumps blood through the
blood vessels. Human heart has to circuits, Pulmonary (to Lungs) and Systemic
(to all tissues in the body)
During pulmonary circulation blood flows between the heart and the lungs,
the heart pumps deoxygenated blood from the heart to the lungs and
oxygenated blood derived from the lungs is pumped into the heart.
Systemic circulation, once oxygenated, the heart pumps oxygenated blood to
the rest of the body and deoxygenated blood is returned to the heart.
2) Blood is transported through blood vessels. Vessels are larger closer to the
heart and the farther away the smaller they are. Vessels are made of epithelial,
smooth muscle, and connective tissue. The muscle tissue is involved in
pumping blood. Constriction increases the pressure inside the vessel, relaxing
decreases the pressure and increases the diameter.
Three types of blood vessels.
A) Arteries carry blood away from the heart, it is typically oxygenated (except
when going to the lungs)
B) Veins return blood to the heart typically deoxygenated and prevent a
backflow of blood (in the other direction) by a series of valves.
C) Capillaries are the smallest and they connect the arteries with veins. At the
capillary beds gas, nutrients and waste are exchanged between the blood and
the body’s tissues. Substances move out of the arteriole end of the capillaries
by blood pressure and move into the venous end of the capillaries by osmotic
pressure. Glucose, O2, nutrients, hormones move out while CO2 and waste
move into the venous end of the capillary, driven by a concentration gradient
.1) Blood has two major components:
A) Formed elements are the cells: includes red blood cells (erythrocytes) which transport O2 to tissues and
removes CO2, white blood cells (leukocytes) a number of cells types that function in the immune response and
platelets (thrombocytes) small fragments of cells that contain enzymes and factors involved in clotting. Oxygen is
transported through the body bound to the protein hemoglobin. In the blood stream leukocytes are transported to
sites of injury and invasion. Once at a problem site they engulf pathogens.
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B) Plasma is water, protein and other solutes. Major proteins include 1) albumins used in transport of hormones,
fatty acids 2) globulins (immunoglobulins) that function as antibodies, 3) fibrinogen involved in clotting.
Humans have a four chambered heart ( 2 atria and 2 ventricle).
4 valves : 2 A/V valves and 2 S/L Valves
SA Node in the Rt. Atrium is the Heart's Pacemaker
Know all structures of the heart.
Two circuits, one is the pulmonary circuit carries blood from the
right side of the heart to the lungs then to the left side of the heart.
The systemic circuit carries blood from the left side of the heart to
the rest of the body.
The Flow of Blood
The flow of blood follows this path a) right ventricle to lungs via pulmonary
arteries, b) lungs to left atrium via pulmonary veins, c) left atrium to left
ventricle d) left ventricle to all body organs via aorta e) body organs to right
atrium via superior and inferior vena cava f) right atrium to right ventricle.
The aorta is the largest vessel in the body, its first branches are to the most
critical organs, first the heart itself then the brain.
The structure of the blood vessels match their functions
1. The thin walls of the capillary cells facilitate diffusion of molecules to and from the interstitial fluids.
2. The arteries are composed of thick wall cells, they are under pressure produced by the heart.
3. Veins, are like arteries, and they have valves, to prevent backflow
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The body of an adult contains over 60,000 miles of blood vessels!
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An adult's heart pumps nearly 4000 gallons of blood each day!
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The average three-year-old has two pints of blood in their body; the average adult at least five times more!
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A "heartbeat" is really the sound of the valves in the heart closing as they push blood through its chambers.
Closed Circulatory Systems: Many invertebrates Arthropods (crabs and insects) and Mollusks (clams) have open
circulatory system. Blood is pumped by one or more hearts through open-ended vessels. The heart has pores that
function as valves, pulling blood in from tissues.
Open Circulatory Systems: Many Invertebrates, and all vertebrates. Blood is confined to vessels this keeps it
distinct from interstitial fluid. In the closed system the atrium receives and the ventricle pumps out.
Fish (unlike humans) have a two chambered heart (one atrium and one ventricle). Fish pump only O 2 -poor blood
Diseases of the Cardiovascular System:
Disease of the cardiovascular system consists of things that compromise the pumping ability of the heart, involve
failure of the directional aids (valves), or narrowing or failure of the pipes. The heart and blood vessels are not
immune to infectious agents or toxins that can decrease function. Injury or failure of the cardiovascular system,
especially the heart, is a critical problem in that peripheral tissues depend on the delivery of nutrients and the
removal of wastes through the blood vascular system.
What causes a heart attack?
A heart attack is death of cardiac muscle cells technical term “Myocardial Infarction” caused by a lack of blood
flow. The lack of blood flow to the heart results in a lack of supply of oxygen and other nutrients. Cardiac muscle
cells atrophy do not regenerate, but leave non-contracting scar tissue. This lack of supply is caused by closure of the
"coronary artery" that supplies that particular part of the heart muscle with blood. This occurs 98% of the time from
the process of arteriosclerosis ("hardening of the arteries") in coronary vessels.
"Embolus is a blood clot which is formed elsewhere and then travels to the coronary artery
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"Angina" is the pain that may be felt when there is a temporary imbalance between the heart muscle's demand for
blood and the ability to deliver enough blood through the arteries
Cholesterol : There are different types of cholesterol, or at least different molecules that carry it.
Cholesterol itself cannot dissolve in the bloodstream, and needs proteins to "carry" it around.
"Bad" cholesterol is that which is carried on a molecule called "LDL" (for "low-density
lipoprotein"), and which has the tendency to release cholesterol into the tissues, including the
vessel walls. A smaller molecule, "HDL" (for "high-density lipoprotein") is also called "good"
cholesterol because it can bring cholesterol back from the tissues to the liver. The higher the level
of HDL and the lower the level of LDL, the less likely it is someone will develop blockages (no
levels guarantee it, though!).
What is blood pressure?
Blood pressure is the rhythmic stretching of the arteries caused by the pressure of blood from the heart
during systole (contraction of atria and ventricle). Pressure is caused by the resistance exerted by the vessels in the
tissues.
The veins have zero pressure. Blood returns to the heart with the aid of muscular contraction, valves and
the lifting of the chest cavity during breathing. The kidney contributes to maintenance of blood pressure by
regulating blood volume. It keeps water when blood pressure is low. With age, the arterial wall become less elastic
causing systolic pressure to rise as the heart has to pump against a less compliant system.
Central control of blood pressure is integrated and regulated by neurons within a region of the medulla oblongata.
A blood pressure is systolic /diastolic of 120/70 indicates the force of the heart beat during systole
(contraction) is 120 mm of mercury and the pressure in the arteries during diastole (resting) is 70 mm Hg.
HYPERTENSION 140/90 is is high blood pressure
100/70-80 is low systolic (result from poor nutrition or glandular disorders)
Hemophilia is an inherited disease in which individuals lack the ability to clot and consequently bleed excessively.
Anemia occurs in individuals having low levels of hemoglobin or low numbers of red blood cells.
Leukemia is cancer of the bone marrow cells that produce leukocytes.
The Respiratory System
Respiration (breathing in and out) is different from Cell Respiration.
Cell Respiration: is the means by which a cell makes energy (ATP)that involves the exchange of O2 and
CO2. Animals need to obtain oxygen and glucose to get rid of carbon dioxide waste. How does the body exchange
the gases?
Components of the Respiratory system: includes the lungs and the
passageways that carry air to the lungs; nasal cavity, pharynx (throat),
larynx (voicebox), trachea (windpipe) and bronchi.
Identify each of these structure in the adjacent figure.
Main Site of Nutrient Absorption is the Alveoli
Functions: gas exchange, O2 in CO2 out.
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Gas exchange involves breathing, the transport of gases and
supplying gases to tissues.
The transport of gases involves diffusion into red blood cells.
Gases are transported within the circulatory system to all
tissues in the body attached to the protein hemoglobin.
Hemoglobin has a large affinity for O2.
Gas exchange requires a moist body surface. All respiratory
surfaces are moist and thin. Gases must be dissolved in water
before they can diffuse in or out.
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Visceral pleura is membrane covering the lung; parietal pleura is
external to the visceral pleura and lines the thoracic cavity.
Environmental adaptations
A. Earthworms are skin breathers, found in moist env. Gas is exchanged from environment into the cells.
B. Gills evolved in most aquatic animals. The increase the respiratory surface by folding and by projecting away
from the body surface. They are aided by a circulatory system.
C. Trachea evolved in insects, they are specialized breathing tubes. The tubes bring external gases directly to the
inner cells, without the aid of a circulatory system.
D. Lungs evolved in most terrestrial vertebrates, they are composed of branched tubes ending in tiny internal sacs,
lined with moist epithelium.
Inhalation is breathing in O2 while exhalation is breathing out CO2. The thoracic cavity (rib cage) enlarges due
to contraction of rib muscles and diaphragm muscles, causing air to move inside the respiratory passageways. All of
the surfaces are lined with moist epithelium. The lungs increase in size, this causes low pressure inside the lungs, so
air moves in to balance the gradient in pressure. Air passes through the nasal cavity, pharynx, trachea, bronchi,
bronchioles and finally reaching the alveolus in the lungs at the tip of the bronchioles. The capillary beds are
interspersed with the alveoli. Here O2 and CO2 diffuse based on their concentration gradients.
Respiratory Adaptations:
Life at high altitude, is colder and has less O2. People born in and adapted to high altitudes have relatively large
hearts, more red blood cells and greater hemoglobin levels.
After a short time, individuals living in lower altitudes acclimate to higher altitudes. Faster heart rate and larger
capillary diameter are replaced over time with deeper and more rapid rates of breathing, more capillaries, and higher
numbers of red blood cells and higher levels of hemoglobin.
Animals like birds are capable of exchanging gases from environments that are inhospitable for humans. Mt Everest
is 28000 feet in altitude, man can not survive because of the cold and low O 2 content. Birds have more efficient
lungs, their hemoglobin has a higher affinity for oxygen, they have larger numbers of capillaries and proteins in their
muscles hold oxygen.
Smoking
The epithelial lining of the lungs traps and removes particles (pollutants, asbestos, tobacco smoke) Tobacco smoke
irritate epithelial cells and destroy the function of cilia and macrophages. This allows more toxins to reach the lung
alveoli. Coughing is the systems attempt to clean the lungs. Smokers often get emphysema, the alveoli become
brittle and eventually rupture. The leading cause of death among smokers is cardiovascular disease. Smoking
negatively affect prenatal development and development of infants and children.
Emphysema and chronic bronchitis together comprise chronic obstructive pulmonary disease
Emphysema is a condition in which there is over-inflation of structures in the lungs known as alveoli or air sacs.
Damage to the air sacs is irreversible and results in permanent "holes" in the tissues
The lungs also lose their elasticity, which is important to keep airways open. The patient experiences great difficulty
exhaling.
Emphysema doesn't develop suddenly, it comes on very gradually. Years of exposure to the irritation of cigarette
smoke usually precede the development of emphysema.
Chronic bronchitis: when airways of the lungs become inflamed and clogged with mucus, often in response to
environmental irritants.
The Digestive System
Function of the digestive system is to get food into a usable form for the body and rid the body of
waste. Food is digested by mastication, churning and enzymatic action then absorbed by the body through
capillaries. Macromolecules are broken into monomers using ENZYMES. Monomers are absorbed into
blood by the small intestine.
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Digestive System includes the digestive tract, a long tube that begins in
the mouth and ends at the anus. Along the way there is a stomach, glands (salivary,
liver, pancrease) and large and small intestine.
Enzymes you should know.
Mouth Amylase Hydrolyzes Starch to Maltose
Stomach Pepsin
Hydrolyzes Protein to Polypeptides
Small Intestines
Hydrolyzes all large molecules to monomers
Sucrase Hydrolyzes sucrose
Maltase Hydrolyzes maltose
Lipase Hydrolyzes lipids following emulsification by Bile
Nucleases Hydrolyze nucleic acids to nucleotides.
The major site of nutrient absorption occurs in the small intestine. The design
of the small intestine provides a large surface area. The tubing alone is 6 meters
long, with several layers of folding. The wall is folded into circular pleats. The
pleats contain projections (villi) of cells and the cells have further projections
(microvilli). The villi contain capillaries and lymph ducts. Nutrients diffuse from
intestine chamber to blood. Nutrient enriched blood passes first to the liver. The
liver processes or stores the nutrients (glycogen).
Components of the Digestive System:
An alimentary canal (tube) and accessory glands.
The alimentary canal includes the mouth, oral cavity, tongue, pharynx,
esophagus, stomach, small intestine, large intestine, rectum and anus.
Food is moved through the alimentary canal by wavelike contractions of
smooth muscles.
The glands include the salivary glands, pancreas and liver. They
secrete digestive enzymes into the cavities.
liver makes and releases bile which aids in the breakdown of fats
gallbladder stores the bile until it is needed
pancrease makes enzymes and bicarbonate ions to neutralize the
acid chyme and raise its pH.
The major organ of chemical digestion and nutrient absorption is the
small intestine. The liver and gallbladder makes secretions into the small
intestine.
The large intestine reclaims water. It is 1.5 m long. Prokaryotes living in
the large intestine include E. coli and produce vitamins that humans
cannot make.
Undigested material (fiber) is compacted by peristalsis and stored in
the rectum until defecated.
The appendix is a gland at the top of the large intestine that has an
immune function. Appendix can become infected because of
irritation or because its opening is blocked by undigested foods
Identify each organ and its function
The total digestive process takes about 5-6 hrs.
The steps in digestion are:
Ingestion: Mechanical processing begins in the mouth with chewing and lubrication that involves mucous
and salivary secretions. Aided by teeth food is crushed, shredded, ground into smaller parts. Salivary juices contain
lubricants, buffers, antibacterial agents, and digestive enzyme (amylase). Amylase hydrolyzes starch. The pharynx
when we are not eating is open to the larynx and the trachea used for breathing, when we swallow, the trachea is
closed off and the food is directed to the esophagus. The esophagus is merely a muscular tube that transports food
from the mouth to the stomach.
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Digestion: Food is stored in the stomach and broken down with acid and enzymes. The inner surface of the
stomach is highly folded and has pits that terminate into gastric glands. Chemical digestion in the stomach is aided
by contractions of smooth muscle in the stomach wall. Protein digestion into smaller polypeptides occurs by the
action of the enzyme pepsin. Gastric Juices include a) mucus protects the stomach lining and lubricates b)
hydrochloric acid which provides the proper pH for the action of pepsin, it also activates pepsin and it helps to
hydrolyze proteins. Hydrochloric acid has a pH of 1.
Gastric activity is initiated by a nervous signal from the brain (after seeing, smelling or tasting food) which
stimulates the secretion of gastrin (a gastric gland hormone).
Absorption. Once molecules have been broken down into small molecules they can enter the cells of the body.
Elimination is the release of undigested material
Health Watch
Heartburn is caused by an overflow of the stomach contents into the esophagus.
Ulcers are open sores on the stomach lining. Leads to pain in the abdomen associated with eating. The major cause
of ulcers is the bacterium Helicobacter pylori.
Ulcers are also caused by nonsteroidal anti-inflammatory drugs, such as aspirin and ibuprofen.
The four macromolecules: Carbohydrates, Proteins, Lipids and Nucleic Acids. Once carbohydrates and proteins
are broken down enough they move out of the small intestine through the associated capillary bed. The veins from
these capillaries go to the liver. The nutrients are further refined in the liver then through veins they go on to the
heart. The heart now takes them to all tissues in the body.
Diet and Digestive Adaptations
1. Herbivores and omnivores have longer alimentary canals than do carnivores (to allow more time and surface area
for digesting plant material.
2) Most herbivores rely on the cellulose-digesting enzymes of prokaryotes and protests. Populations of these
organisms are housed in parts of the animals digestive track.
Nutrition
A Healthy Diet should
a. Fuel the body
b. Provide raw material for synthesis of needed molecules
c. Provide essential nutrient an animal cannot make. Of the 20 amino acids needed our bodies
make 11 but 9 must be obtained in the diet. 13 vitamins must be obtained in the diet. Fats are essential to
diet for the manufacture and uptake of fat soluable vitamins. Chemicals other than carbon, hydrogen,
oxygen and nitrogen are considered minerals, they too must be obtained in diet. Fiber is essential for
proper elimination of waste.
Control of the Internal Environment in Mammals
Ectotherms warm themselves by absorbing heat from the surroundings
Includes: Amphibians, fish, reptiles
Endotherms derive most of their body heat from their own metabolism.
Includes: Birds and mammals
Thermoregulation is the control of temperature. External temperature fluctuates how does the body
adjust?
a.
Mammals change their metabolic rates to generate heat. Muscle movement (moving around or shivering)
generates additional heat
b.
Increase the thickness of the skin or of hair. Hair and fur have insulating power.
c.
Changes in blood flow to or from the changes the temperature of the skin and subsequent heat loss by
convection.
d.
Cooling occurs by evaporation during sweating or panting
e.
Relocating to a different physical location
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f.
Bathing
Osmoregulation is the control of the concentration of water and dissolved solutes.
Diffusion the movement of solutes from a high concentration to a low concentration Osmosis the
movement of water from a high concentration to a low concentration
Animal cells would lyse if there was a net gain in water and would die from a net loss (dehydration).
Animals lose water in urine, feces, perspiration, evaporation and breath.
Animals gain water in food and drink
Excretion is the disposal of nitrogen – containing waste
Nitrogen containing wastes come mostly from the breakdown of proteins and nucleic acids
The forms of Nitrogenous wastes:
Aquatic animals secrete ammonia (the most toxic form)
Terresterial animals convert ammonia to less toxic forms:
 Humans secrete urea,
 Birds, Insects, reptile and snails secrete uric acid (its more concentrated therefore conserves water
Urinary system is the excretory system plays a role in osmoregulation and excretion of nitrogen wastes.
This system functions in the elimination of waste products from the blood through the formation of urine. The key
functions is excretion which involves filtration, reabsorption, secretion and excretion.
IDENTIFY ALL ORGANS AND KNOW THE
Four Organs in the Urinary System:
1. Kidneys: this is the processing center for the excretory system. FUNCTIONS
Blood enters and leaves the kidney through the renal artery
and renal vein. The nephron is the fundamental unit of the
kidney and excretory system. Kidneys have several important
functions, including the production of urine.
 maintain water balance by removing excess fluid from
your body.
 remove waste products. Metabolism results in waste
products that become toxic (poisonous) if they are left to
accumulate in your body. The kidney filters the blood to
remove waste products such as urea and creatinine.
 Kidneys maintain normal blood chemistry. Kidneys
make sure you keep the right amounts of potassium,
sodium, phosphorus, calcium, bicarbonate, magnesium
and chloride and get rid of those you don't need.
2. Ureter: this is the conduit that transports urine from the kidney
to the bladder
3. Urinary bladder: this is the site for storage of urine
4. Urethra this is the conduit that transports urine from the
bladder during excretion
Kidneys also make three important hormones - renin, erythropoietin and calcitriol:
 Renin helps regulate your blood pressure.
 Erythropoietin (er-ree-throw-po-e-ten) helps maintain the right amount of blood in your body
(blood volume) by simulating your bone marrow to make more red blood cells.
 Calcitriol helps your body absorb calcium from the food you eat.
The kidney has thousands of blood filtering units called nephrons.
The nephrons are composed of tubules and associated blood vessels. The nephron extracts and refines the filtrate
then releases the urine. The blood filtering region is the Bowman’s capsule and the filtrate refinery includes the
proximal tubule, loop of Henle and distal tubule.
Four Steps to processing Blood and Production of Urine:
Occurs in the Nephrons of Kidney
Filtration Process occurs in Glomerus/Bowmans Capsule
The blood vessels of the nephron include a ball of capillaries called
glomerus. In the glomerus blood pressure forces water and small
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Identify all structure and know their
functions
solutes (salt, Urea, some sugar)out of the blood and into the
nephron tubule. Blood capillaries surround the Nephron . They
helps refine the filtrate.
Reabsorption of solutes occurs mainly in the Proximal tubules
and water in the Loop of Henle: In this process water and solutes
still valuable to the body are reclaimed from the filtrate. NaCl and
H2O are reabsorbed by the filtrate in the proximal and distal
tubules.
 Organisms living in dry environments must reabsorb
water more efficiently. In this case the Loop of Henle is
extra long.
 The reabsorption of water is under hormonal control
(antidiuretic hormone is produced by the hypothalamus
and released from the pituitary). However ADH exerts its
effects on the Collecting Ducts.
Secretion: excess ions, drugs and toxins are secreted from the
blood into the nephron tubule. Reverse of reabsorption.
Excretion: urine passes from the kidney to the outside by way
of the urinary bladder and urethra.
Kidney failure: Failing kidneys cannot get rid of excess fluid. Urine output goes down causing a rise in blood
pressure, shortness of breath and swelling in many areas of the body. Waste products accumulate. The buildup of
waster products in the body results in uremia.
Uremia is "urine in the blood." Uremia affects all the systems in the body When drugs and diet are no longer
effective, patients need treatment to do the work of their failed kidneys. If you lose close to 90% of kidney function,
they need to start dialysis or have a kidney transplant to stay alive.
Dialysis means "to clean the blood." Dialysis removes the waste products and excess water from the body, and
stabilizes blood chemistry.
Reproductive System
Reproductive System functions in the perpetuation of the species (making of offspring). Two separate
systems for making separate but compatible gametes, male and female. Gametes are made in an unfinished form
called:
oocytes in women and stored in the ovaries nurtured in a complex of cells and fluids call follicles. Once a month an
oocyte matures into an egg and travels down the uterine (fallopian tube) in a process called ovulation. At birth an
ovary has all the follicles (the storage unit for the Oocyte, includes Oocyte and nurturing cellular environment) a
women will ever have approximately 40,000-400,000. Only several hundred will release eggs, once every 28 days.
Oogenesis is the process by which the egg is made from the germ cell. The diploid germ cell (oocyte) undergoes 2
meiotic divisions to produce 4 haploid cells. Only one becomes the egg the other three are the polar bodies. FSH
(follicle stimulating hormone) from the pituitary gland stimulates one dormant follicle to develop. LH (leutenizing
hormone) from the pituitary gland, signals the egg to leave the ovary. LH causes the secretion of estrogen and
progesterone to prepare the lining for implanting a fertilized egg.
The gonadotropin hormones (FSH, LH) are regulated by the hypothalamus.
Spermatocytes in men and stored in testes then transferred to the epididymis where they mature. The male releases
some 250 million sperm per ejaculation which travels from the epididymis through the vas deferens and finally the
urethra where it is ejaculated into the vagina. Sperm are made by spermatogenesis the diploid germ cell
(spermatocytes) undergo two meiotic divisions to produce 4 sperm cells, equal in size and potency.
The Female Menstral Cycle
Day 1-7: Bleeding (low estrogen and progesterone) due to a breakdown of the endometrium. Preovulatory
phase of the cycle.
Between 7-14. Following bleeding: Regrowth of the endometrium. Estrogen (EST) levels peak.
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Day 14:Ovulation (this is the point pregnancy can occur): FSH and LH levels are high. They are required
for ovulation. The follicle develops in the corpus luteum. Preparing for fertilization and implantation the lining
secretes EST and PRO. These high levels of EST and PRO inhibit the initiation of new menstral cycles.
If fertilization and implantation does not occur, the corpus luteum disintegrates. Levels of estrogen and
progesterone decrease. FSH and LH levels increase and new ovarian and menstral cycles are initiatied.
Should sperm meet egg there is fertilization. Estrogen and progesterone remain high. The corpus luteum is
maintained because of the secretions of the hormone gonadotropin (HCG) by the developing embryo. Gradually a
placenta replaces the corpus luteum. A zygote forms.
The Male Cycle
During Sexual Arousal: Erectile tissue in the penis swells with blood, essential for insertion into the vagina.
The penis and the clitoris in female vaginal anatomy are homologous structures. Both have glands that are richly
supplied with nerve ending and foreskin that covers the glands.
Ejaculation. 1) A peak in sexual arousal, causes muscles in the epididymis, seminal vesicles, prostate gland
and vas deferens to contract. Forcing sperm and secretions into the vas deferens. 2) The sphincter muscle opens and
the strong muscular contractions force the semen along the urethra and out of the penis.
Sperm and androgen production are also under the control FSH and LH hormones from the pituitary, FSH
increases production of sperm by testes. LH promotes secretion of androgens, mainly testosterone.
Spermatogenesis: Hundreds of millions of sperm is produced daily from puberty onward. 4 sperm cells are
derived from each Oocyte
Semen consists of sperm cells and secretions from glands. 200-500 million sperm in one teaspoon of semen
discharged during a typical ejaculation. The prostate gland secretes a milky alkaline fluid that neutralizes the acidity
of male and female reproductive tracts.
The Pathway Sperm Travels
Testes  Epididymis (storage until develop motility and fertilizing ability)  vas deferens  seminal vesicle 
ejaculatory ducts  urethra
Principles of Embryonic Development
Embryonic development involves cell division, differentiation, and morphogenesis.
 Cell division results in an increase in the number of cells. All the cells result from mitotic divisions
beginning with the zygote.
Fertilization is the fusion of two haploid cells. It results in a zygote. The zygote triggers embryonic
development.
 Differentiation is the development of specialized cells that are organized into tissues and organs. This
differentiation is controlled by the cell's expression of different genes brought on by its contact with the
environment.
 Morphogenesis includes the physical processes that give shape to the animal's body and organs.
Question: How do we go from a single diploid cell at fertilization to an organism that has a variety of cell,
tissue and organ types?
The organism's development is mostly determined by the zygote's genome and the organization of the egg's
cytoplasm. As the zygote undergoes cleavage, the cytoplasm is compartmentalized causing the nuclei of the
different cells to be exposed to different cytoplasmic environments. These different cytoplasmic environments result
in the expression of different genes in different cells. Inherited traits then emerge, in an orderly fashion, in space and
time by mechanisms controlling gene expression.
The steps in the fertilization process are as follows:

The Acrosomal Reaction: This reaction is caused by a discharge of hydrolytic enzymes from the
arcosome of the sperm cell. When the head of the sperm contacts the egg the enzymes are released from a
vesicle. This allows the arcosomal process to elongate and penetrate the jelly coat of the egg. The protein
coating the tip will attach to the exact receptors on the egg's vitelline layer to ensure it is the correct species
of sperm. The enzymes continue to digest the membrane allowing the tip to reach the plasma membrane of
the egg. The two membranes fuse, allowing the sperm's nucleus to enter the egg. A quick depolarization
then occurs locking out all other sperm from the egg.

The Cortical Reaction: The fusion of the sperm and egg membranes stimulates a series of changes in the
egg's cortex. The egg-sperm fusion causes a signal transduction pathway involving a G- protein to stimulate
the release of Ca2+from the egg's endoplasmic reticulum. The Calcium acts as a second messenger and
results in a increase in calcium in target areas. Eventually the zygote membrane area will swell and
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become hard forming a fertilization membrane. This membrane will prevent additional sperm from entering
the egg.

Activation of the Egg: The sharp rise in cytoplasmic calcium also incites metabolic changes that activates
the egg. Cellular respiration and protein synthesis increase; cytoplasmic pH becomes more basic due to a
loss of H+ ; the sperm nucleus swells and merges with the egg nucleus to form the zygote and DNA
replication begins with the first division occurring in about 90 minutes.
Post-Fertilization Events
Cleavage: is a succession of rapid mitotic cell divisions following
fertilization and produces a multi cellular embryo, the blastula. The first
two cleavage divisions are vertical and divide the embryo into 4 cells.
The third cleavage plane is horizontal and produces an 8 cell embryo
with two levels. Continual cleavage produces a solid ball of cells called
the morula. A fluid filled cavity, called the blastocoel develops within
the morula forming a hollow ball of cells called the blastula.
During cleavage the S and M stages of the cell cycle occur, while the G 1 and G2 phase are skipped. Very little gene
transcription occurs causing very little growth in the embryo.
The gradient in the concentration of cellular components like mRNA, proteins, and yolk IS KNOWN AS
“POLARITY”. The vegetal pole of the egg has the highest concentration of yolk. The animal pole has the lowest
concentration .The animal pole marks where the most anterior part (head) of the animal will form. Cleavage in the
animal hemisphere is more rapid than in the vegetal hemisphere.
Gastrulation: rearranges the blastula to form a three-layered embryo with a primitive gut. The three layers produced
by gastrulation are embryonic tissues called embryonic germ layers:
1. Ectoderm is the outer layer of the gastrula. It produces the nervous system, epidermis, epidermal glands,
inner ear, and eye lens.
2. Endoderm produces the lining of the digestive tract lining, liver, pancreas, and lungs.
3. Mesoderm partially fills the space between the ecto and endoderm. The kidneys, coelomic lining, muscles,
skeleton, gonads, heart, muscles, inner layer of the skin and most other organs develop from the mesoderm.
These three germ layers will eventually develop into all parts of the adult animal.
Organogenesis: forms the organs of the animal body from the three embryonic layers. The neural tube and
notochord are the first organs to develop in frogs and other chordates. The ectoderm above the beginning notochord
thickens to form the neural plate that sinks below the embryo's surface and rolls itself into a neural tube that will
become the brain and spinal cord. The notochord stretches the embryo lengthwise and forms the core around witch
the mesoderm cells will develop the muscles of the axial skeleton. As organogenesis continues, other organs and
tissues develop from the embryonic germ layers.
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Know the functions of each organ. And hormones produced.
FEMALE REPRO ORGANS
MALE REPRO ORGANS
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