Body is organized into four levels:
Cells
Tissues
Organs
Organ systems
CELLS
Your body contains around100 trillion cells. You
have more than 100 different kinds of cells.
Human egg
cell
Blood cells
Muscle cells
Nerve cells
Stem Cells
Any embryonic
stem cell is capable
of becoming any
type of tissue found
in the adult body.
– There are adult
stem cells but they
do not divide
forever and they
are also already
specialized.
Tissues
Tissues are a group of specialized cells.
1. epithelial tissue - lines most body surfaces
(skin, nails)
2. Nervous tissue - nerve cells
3. Connective Tissue - fat, cartilage, bones,
tendons, blood
4. Muscle tissue - skeletal (voluntary), cardiac
(involuntary)
Organs
Tissues are organized into organs which have
specialized functions.
ORGAN SYSTEMS
Organs are grouped into organ systems, in which several organs
interact to perform a specific function, such as digestion.
Circulatory
Digestive
Nervous
Endocrine
Reproductive
Integumentary
7. Skeletal
8. Respiratory
9. Muscular
10. Excretory
11. Immune
1.
2.
3.
4.
5.
6.
Many organs
are a part of
multiple organ
systems.
Skeletal System
Skeleton Function
Supports the body, provides protection for
internal organs, and enables movement
The 206 bones of the skeleton are divided
into the axial skeleton and the
appendicular skeleton
Axial Skeleton
the skull, spine,
ribs, and sternum
Appendicular
Skeleton
the appendages or
limbs:
the shoulders, arms,
hips, and legs
BONE STRUCTURE
made of hard compact bone surrounding porous
spongy bone
– Compact bone provides support
– Some cavities of spongy bone contain soft tissue
called bone marrow.
Bone Growth
Early in development, skeleton is mostly cartilage
Bones harden as calcium and other minerals build
up
Thicken and elongate as development continues
Severe bone loss can lead to a condition called
osteoporosis
JOINTS
Where two bone meet
Bones of a joint are held together by strong
bands of connective tissue called ligaments
Types of Joints:
immovable joints- cranial
bones in skull
slightly movable jointsvertebrae, bones in rib cage
freely movable joints- elbow,
knees, fingers, etc.
Muscular System
The muscular system:
•Moves the limbs and
trunk
• Moves substances
through the body
• Provides structure and
support for the body.
Three types of muscle tissue
Muscles and Movement
Muscles are attached to bones by tendons
Muscle pairs move parts of the body by pulling on
bones
– Flexor muscle- causes a joint to bend
– Extensor muscle- causes a joint to straighten
Muscle tissue contains large amounts of
contractile protein filaments called actin and
myosin
Muscle Contraction
Energy is required for muscles to contract
2. The ATP used is usually supplied by aerobic
respiration
3. During exercise oxygen is consumed at a
sustainable, steady rate, and aerobic respiration
yields most of the ATP
4. Aerobic exercise makes the heart pump more
efficiently and thus increases the energy available
to muscles
1.
Integumentary
System
1. Epidermis
Outer layer of skin composed of a protein called
Keratin that makes skin tough and waterproof
Inner layer contains Melanin- a pigment that
affects skin color
These cells are damaged by the environment
2. Dermis
below epidermal layer, consists of nerve cells ,
blood vessels, hair follicles and sweat glands
3. Subcutaneous tissue
Anchors skin to underlying organs.
Below dermis fat and connective tissue.
Skin Disorders
Most skin disorders are caused by damage to the epidermis
Acne
Skin cancer caused by overexposure to UV radiation
Circulatory System
Heart
Blood
(hemoglobin)
Blood Vessels
The
circulatory
system:
• Consists of
the
cardiovascular
and lymphatic
systems.
• It transports
nutrients,
hormones and
gasses and rids
your body of
wastes.
Lymphatic system
• Consists of lymph nodes
and vessels. (Tonsils, Spleen,
Thymus, Bone marrow)
• Lymphatic system collects
and recycles fluids that are
leaked from the
cardiovascular system.
• It also helps fight
infections
Cardiovascular
system
Consists of blood vessels, blood and the heart.
Transports materials, removes wastes, and
distributes heat.
Blood vessels
Veins bring blood to the heart and
arteries carries blood from the heart.
Capillaries are tiny
blood vessels that
allow the exchange of
gas, nutrients, and
hormones.
Endothermy
Enables the body to maintain homeostasis at all times
Temperature is regulated by flow of blood through blood vessels
just under the skin.
Your brain uses chemical and electrical
signals to communicate with the rest of
your body.
Three major parts: cerebrum, cerebellum
and the brain stem.
Cerebrum
Brain stem
The spinal cord - links the brain
to the peripheral nervous
system (which branches
throughout the body).
Central Nervous System
– consist of brain and spinal
cord
Nerve Cells
The nervous system contains a
complex network of nerve cells
(neurons).
Neurons structure allows it to
conduct electrical signals
(nerve impulses).
Neurons transmit info through
the body. They enable functions
such as movement, thought,
emotion and learning.
Sensory Systems
Respiratory System
The respiratory system:
• Consists of the lungs, nose, mouth and trachea
• The reparatory system moves air into and out of the
lungs
• Controls gas exchange between blood and the
lungs.
• We inhale Oxygen (O2) and exhale Carbon
Dioxide (CO2)
The lungs
The diaphragm – muscle that
aids in respiration
Your bronchioles are
some of the smallest
airways in your lungs.
They lead to tiny ducts
that lead into elastic air
sacs (alveoli), which
diffuse oxygen to your
bloodstream and receive
carbon dioxide waste,
which is then exhaled.
After breathing, gases must be transported by
the cardiovascular system and exchanged at the
cells.
Digestive System
Liver
Intestine
Stomach
Mouth
Gallbladder
The digestive system:
• Extracts nutrients from food and then absorbs
them. It removes wastes and maintains water
and chemical balances.
Usable compounds from food are absorbed into
capillaries in villi (in intestine). Compounds not
absorbed are excreted.
Nutrients
•Organic nutrients include carbohydrates, fats, proteins
or amino acids, and vitamins. Inorganic chemical
compounds such as minerals; water and oxygen may
also be considered nutrients.
•A nutrient is essential to an organism if it cannot be
synthesized by the organism in sufficient quantities and
must be obtained from an external source
• Carbon, nitrogen, hydrogen, oxygen and
phosphorus are elements that we consume in the
largest quantities.
• Nutrients that are not
needed in large quantities are
called micronutrients such as
vitamins and minerals.
• Nutrients are needed for
growth, maintenance, and
repair of the body.
The digestive system:
• Consists of the mouth, throat, esophagus, stomach,
liver, pancreas, small and large intestine.
Digestive System
Stomach: Stores and
mechanically breaks down
food.
Small intestine: Where most
chemical digestion occurs
Large intestine: No digestion
takes place here, wastes are
stored. Many bacteria live in
the large intestine.
Nutrients are absorbed in
both intestines.
Liver: releases bile, detoxifies
poisons, and helps to
maintain blood sugar levels.
Gall Bladder: Stores
bile that helps digest
food.
Pancreas: Secretes enzymes
that aid in digestion
Excretory
System
Kidneys
Bladder
The excretory system:
• Consists of the bladder, kidneys, ureters,
urethra, skin and lungs.
• It removes wastes
from blood and
regulates the
concentration of
bodily fluids.
Bladder - collects urine excreted by
the kidneys prior to disposal by
urination. Urine enters the bladder
via the ureters and exits via the
urethra.
Kidneys – help maintain
homeostasis by maintaining
bodily fluids and filtering the
blood.
Reproductive System
Reproduction produces gametes and offspring
Gametes are sex cells: eggs and sperm
Fertilization
Sperm and egg cells both have a haploid number
of chromosomes.
Embryonic stem cells
differentiate into many
different types of body
cells.
Endocrine
System
The endocrine system :
• Composed of the hypothalamus gland,
pituitary gland, pancreas and many other
endocrine glands.
• Regulates body temperature, metabolism,
development, and reproduction.
• It also maintains homeostasis and regulates
organ systems.
• Synthesizes and secretes hormones.
Pituitary gland – secretes
hormones and regulates functions
such as growth, blood pressure,
and water and osmolarity
regulation
Hypothalamus gland – synthesizes
and secretes neurohormones. It
regulates body temperature, blood
sugar, water balance, sleep and
emotions.
Adrenal Gland – synthesizes
adrenaline. Maintains stress response.
Immune
System
Adenoids
Tonsils
Spleen
Bone Marrow
Appendix
Large intestine
Immune system:
• Defends against pathogens.
• Consists of cells and tissues throughout your body.
- White bloods cells
- Lymph nodes
- Vessels
- Skin
• The immune system can recognize invading bacteria,
viruses, and toxins.
• Each system can quickly mobilize the best defenders to
search out and destroy these invaders.
• Each system has a memory and learns from every
attack.
A white
blood cell
stalking a
bacterial cell
Antibodies – proteins used by the immune
system to identify and neutralize foreign
invaders.
Antigen – a
molecule that will
stimulate an
immune
response. They
are usually
proteins and parts
of viruses.
The body contains four large fluid-filled
spaces.
They house and protect the major internal
organs.
1. Cranial cavity
2. Thoracic cavity
3. Abdominal cavity
4. Pelvic cavity