1. Structures and Functions
Introduction to the Body Systems
Structures and Functions

2. Human Body Systems
The levels of organization in a multicellular organism include cells, tissues, organs and organ systems.

3. Levels of Organization - Cells
Cells – basic unit of structure and function in living things
Individual cells tend to be specialized
Specialized cells perform a particular function

4. Levels of Organization - Tissue
A group of cells that perform a single function
4 basic types of tissue
Epithelial tissue – glands and tissues that cover the interior and exterior body surfaces
Connective tissue – provides support for the body and connects its parts
Nervous tissue – transmits nerve impulse throughout the body
Muscle tissue- along with bones enables the body to move

5. 11 Human Organ Systems

6. The Nervous System Structures: Brain Spinal cord Peripheral nerves
Function:
Gathers and interprets information
Coordinates responses to changes in internal and external environment
Regulates body activities

7. Integumentary System Structures: Function: Skin Hair Nails Covers body
Protection against infection and injury
Helps regulate body temperature
Removes wastes
Protects against UV radiation
Produces vitamin D

8. Respiratory System Structure: Function: Nose Bronchi
Pharynx Bronchioles
Trachea Lungs
Alveoli
Function:
Takes in oxygen needed for cellular respiration
Removes carbon dioxide from the body

9. Digestive System Structures: Function: Mouth Intestines Pharynx Liver
Esophagus Pancreas
Stomach Rectum
Salivary glands Gall bladder
Function:
Take in and break down food
Absorb nutrients
Remove indigestible material

10. Excretory System Structure: Function: Kidneys Ureters Lungs Urethra
Urinary Bladder
Skin
Function:
Filters blood and removes waste products from cellular metabolism (urea, water, carbon dioxide)
Helps the body maintain homeostasis

11. Skeletal System Structure: Function: Bones Ligaments Cartilage Tendons
Provides shape and support for the body
Protects the internal organs
Allows for movement
Stores minerals
Produces blood cells

12. Muscular System Structure Function Skeletal muscle Smooth muscle
Cardiac muscle
Function
Moves the body
Moves blood through blood vessels
Moves food through the digestive tract

13. Circulatory System Structure: Heart Arteries Veins Capillaries Blood
Function:
Brings oxygen, nutrients, and hormones to cells
Fights infection
Removes cell wastes
Helps to regulate body temperature

14. Endocrine System Structure: Glands Hypothalamus Pituitary Thyroid
Thymus Adrenal Pancreas
Ovaries Testes
Hormones
Insulin, Glucagon, Thyroxin, Adrenalin, Estrogen, Testosterone, Human Growth Hormone, etc.
Function:
Controls growth, development and metabolism
Helps maintain homeostasis

15. Reproductive System Structure: Function: Males Females
Testes Ovaries
Epididymis Fallopian tubes
Vas deferens Uterus
Penis Vagina
Function:
Produces reproductive cells
In females – nurtures and protects the developing embryo

16. Immune System Structure: Function: White blood cells Thymus Skin
T cells
B cells
Phagocytes
Thymus
Skin
Function:
Fight off foreign invaders in the body

17. Lymphatic System Structure: Function: Lymph nodes Lymph vessels Spleen
Collects fluid lost from blood vessels
Returns fluid to the circulatory system
Kills foreign organisms

18. Maintaining Homeostasis
Homeostasis – means “keeping things in balance”
Homeostasis is the process by which organisms keep internal conditions relatively constant despite changes in external environments.
Non- living example – Heating system of a house
Feedback inhibition (negative feedback) – process in which a stimulus produces a response that opposes the original stimulus

19. Regulation and Hormones
Some of the properties kept in check by homeostasis are:
Body temperature
Blood glucose
Water potential
Oxygen and carbon dioxide concentrations