3.1: The Hierarchy of Structure in Animals
pg. 73
Hierarchy – an organizational structure, with more complex or
important things at the top and simpler or less important things
below it.
Tissue – a collection of similar cells that perform a particular, but
limited, function.
Organ – a structure composed of different tissues working together
to perform a complex body function.
Organ System – a system of one or more organs and structures that
work together to perform a major vital body function such as
digestion or reproduction.
Complex multicellular organisms are made up of many different
types of specialized cells, performing a specific function, working
together to support the organism.
Single celled organisms, bacteria and blue-green algae, must
function on their own, with the cellular organelles maintaining
cellular homeostasis. The cells that are apart of the a multicellular
organism can not live on their own.
Levels of Organization
There are 7 kingdoms of organisms, where the Animal Kingdom is
only one. The Animals which make up this kingdom range from
single celled organism (bacteria) to simple mulitcellular (jellyfish),
to more complex (earthworm), to highly complex multicellular
animals (humans).
The animal itself is based on cells organized in a way that allows
them to perform all of life’s functions. This hierarchy has the most
complex on top and the least complex at the bottom.
Cells working together form tissues (Muscle cells). When different
tissues work together they create organs (Heart). When organs
work together for a common purpose create organ systems
(Circulatory System). The functioning of the whole organism
depends on the hierarchy of organization within the animal.
Organ Systems
The task of organ systems is to perform basic functions, obtain
oxygen and nutrients and eliminate wastes. Also sense and respond
to their environment, grow and repair damage, and reproduce.
Organs
Each system is made up of specialized organs, working together to
perform the overall function. The digestive system is made up of
many organs; stomach, small and large intestine, liver and
pancreas.
Tissues
There are four major types of tissues; epithelial, connective,
muscle, and nerve tissues. Each of these types of tissues are found
in most organ system.
Epithelial Tissue – (epithelium) is a thin sheet of tightly packed
cells that covers body surfaces and lines internal organs and body
cavities.
Connective Tissue – a specialized tissue that provides support and
protection for various parts of the body.
Muscle Tissue – is a group of specialized tissues containing
proteins that can contract and enable the body to move.
Nerve Tissue – are specialized tissue that conducts chemical
electrical signals from one part of the body to another.
Check Your Learning: questions 1 – 6, pg. 76
3.2: Stem Cells and Cellular Differentiation
pg. 77
Cellular Differentiation – is the process by which a cell becomes
specialized to perform a specific function.
Cellular differentiation is instructed by the genetic information
(DNA) found in the nucleus of the cell. This information is passed
on from the parent to its offspring. (Asexual or Sexual)
Stem Cells
Stem Cells – an undifferentiated cell that can divide to form
specialized cells.
Figure 1: In this example, each daughter cell differentiates into two different types of
specialized cells: a nerve cell and a skin cell.
Stem cells can divide into 2 daughter cells through the process of
mitosis and cytokinesis. The 2 new daughter cells can differentiate
into different types of cells, depending on which part of the DNA
instructs the cell.
There are 2 types of stem cells, embryonic and tissue stem cells.
Embryonic stem cells can differentiate into any type of cells, while
tissue stem cells can specialize within specialized tissues, bone
morrow produces, red blood cells, white blood cells, and platelets.
Cord Blood Cell Banking
Blood found in the umbilical cord immediately following birth is a
rich source of stem cells. These cells are collected and stored in
case it is needed later in the child’s life. (Cancer – leukemia)
Tissue Stem Cell Transplantation
Cord blood and Tissue stem cells are easily isolated. Bothe can be
used to treat diseases. Chemotherapy is used to kill all white blood
cells and bone marrow. Health stems are used to replace the bone
morrow cells and regenerate health blood cells
Regeneration and Tissue Engineering
Regeneration refers to the ability or tissue to repair itself. Skin,
muscle and bone can re-grow and heal injured tissues. But not all
cells are capable of regeneration, nerve cells.
Check Your Learning, questions 1 – 7, pg. 79
3.3: The Digestive System
pg. 80
Digestive System – the organ system that is made up of the mouth,
esophagus, stomach, intestines, liver, pancreas, and gall bladder,
the system that takes in, breaks up, and digests food and then
excretes wastes.
The four components of the digestive system are:
Ingestion, Digestion, Absorption, and Elimination.
There are two types of digestion:
Mechanical Digestion and Chemical (enzyme) Digestion
The digestive system is made up of the digestive tract and the
accessory organs.
The Digestive Tract
The digestive tract is a long tube, with two openings at either end,
with a series of organs, in which the food must pass through. Some
organism digestive tract may be simple, earthworm, or more
complex, human.
The Human digestive tract is made up of many organs lined with
epithelial tissue. There are also Goblet cells that secrete mucus,
which protects the tract from digestive enzymes and allows the
food to slide through the tract. Nerve and Muscle tissue also
support the digestive tract.
Vomiting and diarrhea are special occurrences that the system uses
to rid itself of bacteria producing toxins, very rapidly.
Figure 1: In a human, the breakdown of food starts in the mouth and continues until
nutrient absorption occurs in the small intestine.
The Mouth (Ingestion & Digestion)
The mouth is the entry point for food, and is where digestion,
mechanical – chewing and chemical – amylase enzyme, starts.
Saliva is secreted in the mouth which contains the enzymes and
lubricates the food.
The Esophagus
This is a muscular tube, responsible for transporting the food from
the mouth to the stomach. This is done through rhythmic
contractions called peristalsis. This is controlled through the nerve
tissue.
The Stomach (Digestion)
The main function of the stomach is to hold food, churn
(mechanical) it and release an enzyme use for protein digestion.
Hydrochloric acid is released, with a goal to kill and microbes
found in the food. Muscle and nerve tissues are important here.
The Intestine (Small and Large) (Digestion & Absorption)
The lining of the intestine secrete mucus and has a high
concentration of blood vessels.
The Small intestines are roughly 6 to 7 m long and 2.3 cm in
diameter. Most of the digestion occurs here, and absorption of
nutrients into the circulatory system.
The Large intestines are roughly 1.5 m long and 7.5 cm in diameter.
Here waste materials are stored and water and vitamins are
absorbed. The waste products are released into the environment.
(Elimination)
Accessory Organs
The Liver, Gall Bladder and Pancreas are organs involved in the
digestive system, but food does not pass through them, they secrete
enzymes into the digestive tract.
The Liver produces bile which is stored in the Gall Bladder. The
bile is used to emulsify fats.
The Pancreas secretes many different enzymes to breakdown food
molecules, but most importantly it secretes Insulin, which controls
blood sugar levels and controls Diabetes.
3.4: The Circulatory System
pg. 83
Circulatory System – the organ system that is made up of the heart,
the blood, and the blood vessels; the system that transports oxygen
and nutrients throughout the body and carries away wastes.
The five components of the Circulatory System;
Pump, Vessels, Transport Medium, Exchange Area, and Valves.
The function of the Circulatory System is to transport substances
around the body, such as; oxygen from the lungs and nutrients
from the small intestines, and carry wastes to lungs and kidneys.
The Circulatory System is also responsible for maintaining
homeostasis, such as; body temperature, and fight diseases.
Figure 1: The circulatory system connects all parts of the body. In this diagram, the
oxygenated blood is shown in red. The deoxygenate blood is shown in blue.
Parts of the Circulatory System
Blood (Transport Medium)
Blood is connective tissue that circulates throughout. There are
four components that make up blood;
a) Red Blood Cells – the greatest percentage, 45% of the
blood’s volume. Contains a protein called hemoglobin, which
increase the oxygen carrying capacity by 70%. Hemoglobin
mixed with oxygen causes your blood to turn red.
b) White Blood Cells – are infection fighting cells (Immune
response), which recognize and destroy bacteria and viruses.
These cells make up less than1% of your blood volume.
c) Platelets – are tiny cells responsible for blood clotting. These
cells make up less than 1% of your blood volume
d) Plasma – is a protein rich liquid that carries the blood cells.
This fluid makes up 55% of your blood volume.
The Heart (Pump)
There three types of tissue which make up the heart; cardiac
muscle tissue, nerve tissue, and connective tissue. Cardiac muscle
tissue is found only in the heart and is capable of synchronized
contractions and can conduct nerve impulses.
The heart’s rate of contraction at rest is usually 60 beats per minute
and increases depending on your physical activity, stress,
temperature, time of day, and when you have eaten.
Blood volume is 5 L, which passes through your heart every
minute.
The heart has four chambers, Left/Right Atrium, and Left/Right
Ventricle. Blood is pumped into two different pathways: the
Systemic system and the Pulmonary System. The heart has valves
to maintain one way directional blood flow.
Blood Vessels (Vessels, Valves, and Exchange Area)
There are three types of blood vessels:
Arteries – carry blood away from the heart. Aorta carries blood to
the Systemic System and your body tissues. The Pulmonary
Arteries carries blood to the Lungs.
Veins – carry blood to your heart. Vena Cava delivers blood to the
Right Atrium from the Systemic System, while the Pulmonary
Veins deliver blood to the Left Atrium.
Veins also contain valves to maintain one way directional flow of
blood.
Capillaries (Exchange Area) – Capillaries link the arteries and
veins together. This is also the area for nutrient and waste
exchange between the cell tissues and blood vessels. Every part of
your body is supplied with blood through a network of capillaries.
Diseases and Disorders of the Circulatory System
Coronary Artery Disease -
Heart Attack Check Your Learning: questions 1 – 9, pg. 87
pg. 85
3.5: The Respiratory System
pg. 91
You take a breath fifteen times within a minute. Your breathing
rate is controlled automatically, when you begin to exercise, your
breathing rate increases.
The respiratory system is responsible for gas exchange. Oxygen is
taken in, while carbon dioxide is released as a waste gas from
cellular respiration.
Glucose + Oxygen → Water + Carbon dioxide + ATP
The circulatory system works with the respiratory system and
carries the gases to and from the body tissues.
Structural Features
There are three components of a gas exchange system;
A moist and thin membrane
A sufficient size gas exchange area
A transport system
The structures responsible for gas exchange are the lungs and other
organs that connect them to the outer environment.
The path in which oxygen will follow to enter your body is, mouth
or nose, pharynx, trachea, bronchi, bronchioles, and alveoli.
The trachea is lined with epithelial cells, which are responsible for
trapping foreign particles from entering your lungs. These cells
will secrete mucus which traps the particles and have cilia (hair
like projections) which sweep the particles up and out of the
windpipe.
The trachea is supported by cartilage rings, which keeps the
trachea open at all times.
Figure 2: (a) the human respiratory system, (b) Epithelial cells with cilia.
Gas Exchange
Alveolus (Alveoli – plural) is a tiny sac of air in the lungs that is
surrounded by a network of capillaries; where gas exchange takes
place between air and blood.
The main purpose of the respiratory system is gas exchange.
Oxygen reaches the Alveoli sacs, which are surrounded by
capillaries. Here oxygen diffuses from the alveoli into the
capillaries. At the same time carbon dioxide diffuses from the
capillaries into the alveoli, to be transported out of the body.
Figure 3: (a) Each alveolus is surrounded by a capillary network to ensure a good blood
supply. (b) the alveoli provide a huge surface area in the lungs across which oxygen and
carbon dioxide can diffuse.
Concentration gradients are responsible for this continuous
movement of gases. The Alveoli always has a high concentration
of oxygen, while the blood has a low concentration. It is vice versa,
for carbon dioxide, produced in the cells traveling back to the
lungs.
Breathing
Breathing is made up of inhalation and exhalation.
Inhalation – the taking air into the lungs
Exhalation – releasing air out of the lungs
These processes are controlled by the diaphragm and intercostals
muscles of the ribs. When you inhale, the diaphragm contracts and
the ribs move up and outward, which increases the chest cavity
volume and drops air pressure. Air enters the lungs.
When you exhale, the diaphragm relaxes, along with your ribs, the
cheat cavity volume decreases, pressure increase and air moves out
of your lungs.
Breathing is involuntary, we do not think about breathing, it just
occurs. You can hold your breath but not indefinitely. Your brain
will override our will, and cause you to breathe. Your brain detects
the carbon dioxide concentration in your blood. If it is high, the
brain will cause you to breathe faster.
The Respiratory System in Other Animals
The role of all respiratory systems is to gas exchange, deliver
oxygen to the circulatory system and to all the body cells, and
remove carbon dioxide. All respiratory systems do this through the
process of diffusion.
The Fish
Fish have gills which is their gas exchange system. Water passes
over the gills and oxygen is diffused out of the water into the
capillaries found in the gills. Carbon dioxide diffuses from the gills
into the water. Water passes over the gills when fish uses their
mouths to create water flow over the gills.
Figure 5: Fish ensure a constant flow of water over their gills by opening and closing
their mouths or by swimming.
Diseases of the Respiratory System (Symptoms??)
Tuberculosis – is an infectious disease, which means that it is
easily passed between people. Bacteria can enter your lungs and
begins to grow. This disease can be fatal if untreated. It is easily
diagnosed by having a chest x-ray.
Cancers – Cause by first and second hand smoking. The smoke
contains carcinogens, causing lung, mouth, esophagus, pancreas,
and bladder cancer.
SARS – Severe Acute Respiratory Syndrome, caused by a virus.
Check Your Learning, questions 1 – 6, pg. 95
3.7: Organ Transplantation
pg. 96
Tissue transplants have been performed since the early 1800’s. The
first organ transplant occurred in 1954, a kidney was transplanted
between identical twins.
Science and technology has advanced very quickly, now
successful organ transplants include the heart, live, lung, pancreas,
and intestines, and tissue transplants include cornea, skin, bone,
bone marrow, tendons, and blood vessels. Organs and tissues can
come from living donors, and some other body parts are taken
from deceased donors.
Benefits and Risks
Both the recipient and donor may benefit from the transplant. First
the recipient has their life extended, with the ability to live
normally and healthy. For the donor it is the satisfaction of saving
someone. The medical researchers benefit also, they gain
knowledge which eventually helps society.
With every type of transplant surgery, there are risks; rejection of
the organ, and infection. Usually the recipient’s immune system is
suppressed to increase the acceptance of the organ.
The donor may also become ill after the operation.
Figure 1: Many Tissues and Organs can be transplanted.
Living Donor Organs
Living donor organs come from living individuals who choose to
donate a kidney, a lobe of their lung, part of a liver.
Lung donations require two donors, portion of a right and left lung.
Only one person is required to donate a kidney, the door has two
and can live with one kidney.
The Liver transplant is special. A lobe of a liver from the donor is
transplanted, and can regenerate and grow, by forming new tissue,
in both the donor and recipient.
Most donors are usually living relatives of the recipient. This
increases the chance of success, decreasing rejection probability,
and decreases waiting time.
Deceased Donor Organs
The majority of organs for transplantation come from deceased
individuals. This decision to donate organs is usually done while
the individual is alive, driver’s license or organ donor cards.
Your family can also donate your organs after death if they so
choose.
Xeno-transplantation
Is the transplanting of body parts from one specie to another
species.
eg. Heart valves from pigs, chemically treated, but
rejection is still a big issue.