Human Body
Systems
Key Ideas of Homeostasis
• How do the skeletal and muscular systems
help the body maintain homeostasis?
• How does the integumentary system help
the body to maintain homeostasis?
• How do the nervous and endocrine systems
help the body to maintain homeostasis?
• How do the digestive and excretory systems
help the body maintain homeostasis?
• How do the circulatory and respiratory
systems help the body to maintain
homeostasis?
Skeletal/Muscular Systems
• These systems enable
movement and provide support
and protection for tissues and
organs.
• Skeletal system has 5 main
functions:
– Support (give body shape
and structure)
– Protection (protect internal
organs)
– Movement (joints allow for
motion)
– Mineral storage (calcium,
phosphorus)
– Blood cell production
(marrow)
How do Muscles Cause Bones to
Move?
• Muscles are
attached to bones
by tendons.
• Tendons are strips
of very strong,
flexible connective
tissue.
• Pairs of muscles
cause bones to
move- one pair
pulls and one pair
pulls the other way
(when one
contracts the other
relaxes).
Three Main Kinds of Muscle
Tissue
• Skeletal- are voluntary, you can control them. They help
move the body.
• Smooth- involuntary, you cannot control them, found in
blood vessels, digestive system, bladder.
• Cardiac- involuntary, found in heart, you cannot control.
Integumentary
System
• Functions of the skin:
– Protection
– Disease prevention
– Temperature control
– Waterproofing
Nervous System
• Consists of two
main parts:
– Central
nervous
system- Brain
and spinal cord.
– Peripheral
Nervous
system- axillary
nerves (arms,
legs).
The Neuron
Nerve cells are the largest in the body.
Types of Neurons
• Motor- transmit messages
from the CNS to muscles
and other organs.
• Sensory- transmit messages
from the sensory organs to
the CNS.
Endocrine System
Has five main
functions:
– Regulate
metabolism.
– Maintain salt,
water, and
nutrient balance
in the blood.
– Control
responses to
stress.
– Regulate
growth,
development,
reproduction.
– Produce
hormones.
Digestive System
• The process
of breaking
down foods
into
molecules
that the body
can use.
• Uses both
chemical and
mechanical
means.
Excretory System
• The removal of
metabolic wastes.
• Metabolic wastes
include: water,
salts, CO2,
nitrogenous
wastes.
• Main organs are:
Kidneys, Ureters,
and Bladder, and
Lungs.
Respiratory System
• The Respiratory
System brings
Oxygen into the
body and and
carries Carbon
Dioxide out of the
body.
• The Lungs are the
main organs of the
Respiratory
System.
Cardiovascular System
What Is the
Cardiovascular
System?The heart,
blood vessels, and
blood make up the
cardiovascular
system.The
cardiovascular
system carries
nutrients, oxygen,
hormones, and
wastes through the
body and distributes
heat to maintain
homeostasis.
Parts of the Circulatory System
• Arteries- carry blood away from the heart.
• Veins- carry blood to the heart.
• Capillaries- exchanges gases and nutrients from
vessels to cells.
The Immune System
• Disease is caused by a disruption in a human
body system that leads to a corresponding
disruption in homeostasis.
• Disease falls into two categories:
– Infectious, can be transmitted from one organism to
another. Infectious diseases are caused by
pathogens.
– Non-infectious, cannot be transmitted from one
organism to another.
• Pathogens can spread disease by air, contact
with contaminated objects, ingesting
contaminated food, by contact with a vector.
• A vector is an intermediate organism that
transfers a pathogen from one organism to
another.
We can avoid disease by practicing:
– Good hygiene
– Living a healthy lifestyle
– Eating completely cooked meat
– Getting enough sleep
– Exercising
– Eating a balanced diet
– Drinking plenty of water
How does the Immune
System Work?
Key Concept: The Immune System
consists of Organs, Cells, and
Molecules that fight infection.
• Your body has organs, cells, and
tissues that protect you from pathogens.
• The body system that fights off infection
is the Immune System.
Immunity
Bodily Defenses:
• Skin- is the bodies 1st line of defense.
• Skin prevents pathogens from entering the
body.
• Oil/sweat make it difficult for pathogens to
survive on the skin’s surface.
• Pathogens enter the body through openings
in the skin (cuts, scrapes), eyes, nose ,
mouth, and ears.
• Tears, mucous, and tiny hairs help to trap
and remove pathogens.