Human Body
Systems
Endocrine System
Controls body functions by using chemicals that
are made by the endocrine glands.
Gland- a group of cells that make special
chemicals for your body.
Hormone- a chemical messenger made in one
cell or tissue that causes a change in another
cell or tissue in another part of the body
- Flow through bloodstream
Organs and/or Glands




Pituitary Gland- “master gland” – this gland
has many functions like helping the thyroid
function properly, skeletal growth, and
regulating the amount of water in the blood
Adrenal Glands- release the hormone called
epinephrine(adrenaline) to help the body
respond to danger
Pancreas- regulates blood glucose levels in
the blood
Thyroid gland- increases the rate at which
you use energy (metabolism)
Organs and/or Glands cont.
 Parathyroid-regulates
calcium levels in the
blood
 Thymus gland- regulates the immune
system, which helps your body fight
disease.
 Ovaries- in females, produce hormones
needed for reproduction
 Testes- in males, produce hormones
needed for reproduction.
Parts of the Integumentary
System
1.
2.
3.
Skin
Hair
Nails
** Largest organ system on the body.
Function of Integumentary
System
Covers your body and helps maintain
homeostasis.
Homeostasis- maintaining a constant
internal state in a changing environment
Layers of Skin
Epidermis- outermost layer of skin ( about 2
sheets of paper thick)
Dermis-The thicker layer of skin that lies
beneath the epidermis
Skeletal System Functions
1.
2.
3.
4.
Ribs protect heart and lungs. Vertebrae
protects your spinal cord. Skull protects
the brain.
Bones store minerals.
Skeletal muscles pull on bones to
produce movement.
Some bones are filled with marrow that
makes blood cells.
Organs of Skeletal System
Bones
Cartilage
Connective Tissue
Muscular System
Made up of muscles that let you move.
Smooth muscles- found in digestive tract
and walls of blood vessels
Cardiac muscle- found only in the heart
Skeletal muscles- attach to your bones for
movement
Voluntary – muscle action under your
control
Involuntary – muscle action not under your
control
Urinary System Function
The organs that remove waste products
from the blood.
Part of the Excretory system-releases waste
from body:
Urinary System- through urine
Integumentary System- through sweat
Respiratory System- releases carbon
dioxide
Parts of the Urinary System
Kidneys- pair of organs that constantly
clean the blood.
Nephrons- filters in the kidneys that
remove waste from the blood where
urine is formed, water and nutrients are
moved
back into the blood vessels to
recirculate in
the body.
Ureter- tube that carries urine to bladder.
Bladder- stores urine until it can be released
from the body.
Urethra- tube that expels urine out of body.
Nervous System Function
Gathers and interprets information, then it
responds to that information as needed.
Central Nervous System(CNS)- brain and
spinal cord
Peripheral Nervous System(PNS)- all parts of
nervous system except for brain and spinal
cord, it consists of the nerves.
The Central Nervous System
CNS
Cerebrum- the largest part of the brain, and
controls voluntary movements and allows
you to sense touch, light, sound, odors,
taste, pain, heat, and cold.
Cerebellum- 2nd largest part of brain and
processes sensory information from your
body, such as skeletal muscles and joints. EX.
Your body’s balance.
Medulla-part of brain that connects to spinal
cord and controls involuntary processes, such as
blood pressure, body temperature, heart rate,
and involuntary breathing.
Spinal Cord-about as big around as your thumb,
the nerves in the spinal cord allow the brain to
communicate with the peripheral nervous
system or nerves.
The Lymphatic System
Function
A group of organs and tissues the collect
excess fluid from the blood and return it to
your blood.
This system helps fight pathogens (a
microorganism that causes disease or a
virus).
Parts of this system
Lymph- the fluid and particles that are absorbed
into lymph capillaries.
Lymph node-small bean shaped masses of tissue
that remove pathogens and dead cells from the
lymph.
Thymus-produces T cells that are ready to fight
infection.
Spleen- largest organ in this system, stores and
produces lymphocytes(attack or mark
pathogens in the blood)
Tonsils-lymphatic tissue located in the nasal
cavity and at the back of the mouth on
either side of the tongue.
 Lymphocytes in the tonsils trap pathogens
that enter the throat.
The Cardiovascular System
(Circulatory System)
Maintains homeostasis (stable internal
environment) in the body.
Carries nutrients and Oxygen to cells and
removes waste such as excess water and
carbon dioxide from the cells.
Also, helps regulate chemical signals by
carrying hormones throughout the body.
Parts of this System



Heart- made of cardiac muscle, and has 4
chambers(right atrium and right ventricle, left
atrium and left ventricle)
The right atrium and right ventricle receive
oxygen-poor blood through veins from the
body and pump it to the lungs to release
carbon dioxide and pick up oxygen
The left atrium and left ventricle receive
oxygen rich blood from the lungs and pump it
out to the body through arteries
Blood Vessels



Arteries- have thicker vessel walls and carry
blood away from the heart to the body
Capillaries- tiny blood vessels(only one cell
thick) that allow the exchange of nutrients,
oxygen, and other substances between the
bodies cells and the blood
Veins- after leaving capillaries blood enters
the veins which carry blood back to the heart
Types of Circulation
Pulmonary Circulation- circulation of blood
between heart and lungs
Systemic Circulation- the circulation of
blood between the heart and the rest of
the body.
Blood
Connective tissue made up of plasma, red
blood cells, platelets, and white blood cells.
Plasma- fluid part of blood contains water,
minerals, nutrients, sugars, proteins, other
substances, red blood cells, white blood
cells, and platelets.
Red Blood Cells(RBC’s)- each rbc has
hemoglobin which is an oxygen – carrying
protein. RBC’s transport oxygen around the
body.
White Blood Cells(WBC’s)- attack
pathogens(bacteria, viruses, other
microscopic particles that make you sick)
and help clean wounds.
Platelets-pieces of larger cells found in bone
marrow, fragments pinch off into
bloodstream, when you get a cut or scrape
platelets clump together to plug the area
and reduce blood loss.
The Respiratory System
Function
A group of organs that take in oxygen(O2)
and get rid of carbon dioxide (CO2 ).
Respiraton- the process by which the body takes in
oxygen and gets rid of carbon dioxide.
VS.
Cellular Respiration- at the individual cell level
glucose + oxygen taken into the mitochondria of
each cell and converted to make energy.
Organs in Respiratory System
Pharynx- or throat, air passes from nose
through throat

the pharynx branches into two tubes the
esophagus(leads to stomach) and the
larynx(contains vocal cords) that leads to
lungs.
Trachea- or windpipe carries air passing
from the larynx to the lungs
 Bronchi-
trachea splits into two branches
called bronchi, one connects to each
lung and each bronchus inside the lung
branches into smaller tubes called
bronchioles.
 Alveoli- each bronchiole branches to
form tiny sacs called alveoli(this is where
oxygen and carbon dioxide exchange)