The document outlines the 11 major organ systems in the human body, detailing their major structures and functions. These systems include the circulatory, digestive, endocrine, excretory, lymphatic, integumentary, muscular, skeletal, respiratory, reproductive, and nervous systems. Each system works collaboratively to support vital processes such as nutrient transport, waste removal, and homeostasis.

1. HOW ANIMALS SURVIVE?

2. An organ system is a group of organs that
work together to perform a certain function in
an organism’s body. Most animals and plants
have organs, which are self-contained groups
of tissues such as the heart that work
together to perform one function.

3. 11 MAJOR ORGAN
SYSTEMS IN THE
HUMAN BODY

4. 1. ) Circulatory System
Major Structures:
Heart, Blood vessels,
Blood,
Functions:
Transports nutrients,
wastes, hormones, and
gases

10. Major Structures:
Mouth, Throat, Esophagus,
Stomach, Liver, Pancreas,
Small intestine, Large intestine
Functions:
Extracts and absorbs nutrients
from food; removes wastes;
maintains water and chemical
balances
2. ) Digestive System

16. Major Structures:
Hypothalamus, pituitary gland,
pancreas
Functions:
Regulates body temperature,
metabolism, development, and
reproduction; maintains
homeostasis; regulates other
organ systems
3. ) Endocrine System

21. Major Structures:
Kidneys, urinary bladder,
ureters, urethra, skin, lungs
Functions:
Removes wastes from blood;
regulates concentration of
body fluids
4. ) Excretory System

26. Major Structures:
White blood cells, lymph
nodes and vessels, skin
Functions:
Defends against
pathogens and disease
5. ) Lymphatic System

29. Major Structures:
Skin, nails, hair
Functions:
Protects against injury,
infection, and fluid loss;
helps regulate body
temperature
6. ) Integumentary System

34. Major Structures:
Skeletal, smooth, and
cardiac muscle tissues
Functions:
Moves limb and trunk;
moves substances through
body; provides structure
and support
7. ) Muscular System

38. Major Structures:
Bones and joints
Functions:
Protects and supports the body
and organs; interactions with
skeletal muscles; produces red
blood cells, white blood cells,
and platelets
8. ) Skeletal System

44. Major Structures:
Lungs, nose, mouth,
trachea
Functions:
Moves air into and out of
the lungs; controls gas
exchange between
blood and lungs
9. ) Respiratory System

47. The respiratory system consists
of air-filled tubes or tracheae,
which open at the surface of the
thorax and abdomen through
paired spiracles. The muscular
valves of the spiracles, closed
most of the time, open only to
allow the uptake of oxygen and
the escape of carbon dioxide.

48. Most amphibians breathe
through lungs and their
skin. Their skin has to stay
wet in order for them to
absorb oxygen so they
secrete mucous to keep
their skin moist (If they get
too dry, they cannot breathe
and will die).

49. Major Structures:
Testes, penis (males),
ovaries, uterus, breasts
(females)
Functions:
Produces gametes and
offspring
10.) Reproductive System

51. Major Structures:
Brain, spinal cord, nerves,
sense organs
Functions:
Regulates behavior, maintains
homeostasis; regulates other
organ systems; controls
sensory and motor functions
11. ) Nervous System