Human Body Systems
Human Body Organization
The Human Body
is composed of
Organ Systems
are composed of
Organs
are composed of
Tissues
are composed of
Cells
Circulatory System
Major Structures
• heart, blood vessels, blood,
lymph nodes and vessels,
lymph , blood cells
Functions
• transports nutrients, wastes,
hormones, and gases
Interactions with other systems
• Nervous system :
– The brain regulates heart rate
and blood pressure.
• Excretory
– Cleans the blood
• Respiratory system
– Gas exchange in the lungs
• Carbon dioxide and Oxygen
Cells of the Circulatory System
• Red Blood Cells carry
oxygen and carbon dioxide.
• White Blood Cells attack
and destroy germs in the
body.
• Platelets are bits of a blood
cell that help stop bleeding.
• Plasma is the liquid part of
the blood. It includes salts,
waste, nutrients, water,
CO2 & O2
Digestive System
Major Structures
• mouth, throat, esophagus,
stomach, liver, pancreas, small
and large intestines
Functions
• extracts and absorbs nutrients
from food; removes wastes;
maintains water and chemical
balances
Interactions with other systems
• Integumentary system
– vitamin D activated in skin
helps the absorption of
calcium from digestive tract.
• Reproduction system,
– Adequate nutrients, including
fats, are essential for
conception and normal
development.
Sequence of food pathway through system
•Mouth, esophagus, stomach, small intestine and large intestine.
1. Food processing starts with ingestion (eating).
• Teeth- mechanical digestion by
masticating (chewing) food.
2. Upon entering esophagus, peristalsis
(wave-like contractions) of smooth
muscle carries the bolus (food ball)
toward the stomach.
3. From the esophagus, bolus passes
through a sphincter (muscular ring) into
the stomach.
4. In the stomach,
food undergoes
chemical and
mechanical
digestion.
5. Gallbladder contains Bile from
liver that emulsifies (breaks into
small particles) lipids (fats),
which helps mechanical
digestion of fats.
7. Parts of the colon absorb water and
minerals from undigested food and
compact the remaining material into feces.
6. Tiny villi (finger-like projections)
cover walls of small intestine.
This increased surface area
causes more efficient food
absorption
Digestive System
What Benefits Do Gut Bacteria Provide?
Bacteria produce enzymes that digest polysaccharides in plant cell walls.
Plants contribute to fiber in our diet for a healthy colon, but the enzymes
released by good bacteria let us get the most nutrition from vegetables
•
•
Some digestive system bacteria make vitamin K and B group vitamins –
(difficult to get from food) Humans can’t make these. Bacteria help maintain
an optimum pH and stimulate the immune system. Gut bacteria breakdown
drugs, hormones and cancer-causing environmental substances
•
Bacteria in the human gut are beneficial to their host, and enjoy a safe
environment . The relationship is an example of mutualism.
Endocrine System
Major Structures
• hypothalamus, pituitary, pineal,
pancreas, thyroid, parathyroid,
adrenal, testes, and ovaries
Functions
• regulates body temperature,
metabolism, development, and
reproduction; maintains
homeostasis; regulates other
organ systems
Interactions with other systems
• Nervous system and
circulatory system
Excretory System
Major Structures
• kidneys, urinary bladder,
ureters, urethra, skin,
lungs; Nephron- filtration
unit of kidney
Functions
• removes wastes from
blood; regulates
concentration of body
fluids
Interactions
• Circulatory system
• Endocrine system
Immune System
Major Structures
• white blood cells, lymph
nodes and vessels, skin,
spleen
Functions
• defends against pathogens
and diseases
Interactions
• Circulatory- delivers
WBC’s where needed
• Skeletal- makes WBC’s in
red bone marrow
Cells of the immune system
What happens:
1. B cells recognize pathogens by the proteins (antigens) on
their surface.
2. Helper T cells activate the B cells.
3. B cells divide to make plasma and memory B cells.
4. Plasma B cells produce antibodies that attach to the
pathogen marking it for destruction.
5. Macrophages see the antibodies and eat pathogen cells
6. Memory cells are stored in the lymph nodes. They give a
rapid immune response the next time the pathogen
attacks.
Integumentary System
Major Structures
• skin, nails, hair, fat, nerves and
blood vessels
Functions
• protects against injury, infection,
production of Vitamin D, and fluid
loss; helps regulate body
temperature
•
Interactions with other systems
– Immune system
• First line of defense
against infection
– Nervous system
• Complex network of
nerves in skin send and
receive impulses to and
from brain, creating
sense of touch.
• Sense heat, cold, pain,
pressure & touch
Cells of the Integumentary
• Melanocyte- makes
pigment (melanin)
• Langerhans' cellfrontline defense for
the immune system in
skin
• Adipose (fat) cellsprovide insulation from
heat and cold
Muscular System
Major Structures
• skeletal, smooth, and cardiac muscle
tissues
Functions
• moves limbs and trunk; moves
substances through body; provides
structure and support
Interactions with other systems
• Skeletal system - provide skeletal
movement
•
Digestive system- controls entrances and
exits of digestive tract
•
Endocrine system- shiver to produce heat
•
Nervous system – helps sense of
balance, pressure
•
Respiratory system- makes diaphragm
contract & relax
•
Cardiovascular system – heart pumps to
provide circulation
Types of Muscle Cells
Cardiac Muscle cells
- are branched and
striped
Skeletal Muscle cells
- are striped and have
many nuclei
Smooth muscles- are
pointed at both ends
Nervous System
Major Structures
• brain, spinal cord, nerves,
sense organs
Functions
• regulates behavior;
maintains homeostasis;
regulates other organ
systems; controls sensory
and motor functions
Nerve Cells
•Sensory (or afferent) neurons: send information from
sensory receptors (e.g., in skin, eyes, nose, tongue, ears)
TOWARD central nervous system.
•Motor (or efferent) neurons: send information AWAY from
central nervous system to muscles or glands.
•Interneurons: send information between sensory neurons
and motor neurons. Most interneurons are located in the
central nervous system.
Reproductive System
Major Structures
• ovaries, fallopian tubes,
uterus, and breasts (in
females); testes and
penis (in males)
Functions
•
The male and female gonads (testes
and ovaries) produce sex cells (ova
and sperm) and the hormones
necessary for the proper development,
maintenance, and production of
gametes and offspring
Egg
Sperm
Gametes of the Reproduction system
Respiratory System
Major Structures
• Nose, mouth, voice box
(larynx), trachea, bronchi,
lungs, alveoli (air sacs)
Functions
• moves air into and out of
lungs; controls gas
exchange between blood
and lungs
Interactions:
• Circulatory system
• Nervous system
Pathway: nose->pharynx->larynx-> trachea->bronchi-> Lungs-> bronchioles
->alveoli
Skeletal System
Major Structures
• Bones, joints and Bone marrow
Functions
• protects and supports body and
organs; interacts with skeletal
muscles; produces red blood
cells, white blood cells, and
platelets
Interactions with other systems
• Nervous System
– Bones provide calcium
needed for proper
functioning of nerve cells
•
Circulatory system
– Skeletal system protects
internal organs and produces
blood cells.
Cells of the Skeletal System
Cells in the Bone that
work with the Circulatory
System