1. Human Body Systems

2. I. Organization of the Body
A. Every cell in the human body is both an independent unit & an interdependent part of an organism.
B. The levels of organization in a multicellular organism include: cells  tissues  organs  organ systems.

3. I. Organization of the Body
1. Cells – are the basic unit of structure & function in living things and can perform uniquely suited jobs.
2. Tissues – groups of cells that perform a single function
4 basic types of tissue include:
1. epithelial tissue – includes glands, covers interior & exterior surfaces
2. connective tissue – provides support for the body & connects parts
3. nervous tissue – transmits nerve impulses throughout body
4. muscle tissue – enables body to move

5. I. Organization of the Body
3. Organs – a group of different tissues that work together to perform a single function.
Example: eye
4. Organ systems – a group of organs that perform closely related functions.

6. II. Maintaining Homeostasis
A. Homeostasis is the process by which organisms keep internal conditions relatively constant despite changes in external environments.
1. Feedback inhibition (negative feedback)
Example; body temperature
Hypothalamus!!

7. III. Eleven Organ Systems
A. The human body systems that work together to maintain homeostasis include:
1. Nervous System
2. Integumentary System
3. Respiratory System
4. Digestive System
5. Excretory System
6. Skeletal System
7. Muscular System
8. Circulatory System
9. Endocrine System
10. Reproductive System
11. Immune System

8. III. Main Structure/Function of Each System
1. Nervous system: includes the brain, spinal cord, nerves. These organs work together to recognize & coordinate the body’s response to changes in its internal & external environments

9. III. Main Structure/Function of Each System
2. Integumentary system: includes skin, hair, nails, sweat & oil glands. They work together to serve as a barrier against infection & injury as well as help regulate body temperature.

10. III. Main Structure/Function of Each System
3. Respiratory system: includes nose, pharynx. Larynx, trachea, bronchi, bronchioles, lungs. These organs works together to provide oxygen for cellular respiration & remove excess carbon dioxide

11. III. Main Structure/Function of Each System
4. Digestive system: includes mouth, pharynx, esophagus, stomach, intestines, rectum. These work together to convert food into smaller molecules to be absorbed.

12. III. Main Structure/Function of Each System
5. Excretory system: skin, lungs, kidneys, bladder, urethra. These organs works together to eliminate waste.

13. III. Main Structure/Function of Each System
6. Skeletal system: bones, cartilage, ligaments & tendons. Work together to support & protect the body as well as store minerals & provide red blood cell formation.

15. III. Main Structure/Function of Each System
7. Muscular system: all muscles found in the body. Works together with skeletal system to produce voluntary & involuntary movement.

16. III. Main Structure/Function of Each System
8. Circulatory system: heart, blood vessels, blood. Work together to bring oxygen, nutrients, & hormones to cells. Helps fight infection & remove cell waste

17. III. Main Structure/Function of Each System
9. Endocrine system: hypothalamus, pituitary, thyroid, parathyroid, adrenals, pancreas (ovaries/testes). Work together to control growth, development, & metabolism.

18. III. Main Structure/Function of Each System
10. Reproductive system: males- testes, epididymis, vas deferens, urethra & penis; females- ovaries, fallopian tubes, uterus, vagina. Are responsible for reproducing sex cells.

19. III. Main Structure/Function of Each System
11. Immune system: white blood cells, thymus, spleen, lymph nodes, lymph vessels. These organs help protect the body from disease.