1. Intro to Body Systems and the Nervous System
12 major systems

2. Multicellular humans The human body contains 50 to 75 trillion cells
Cells are organized and given a specific task to make the whole organism work

3. How are humans organized?
Cells (~300 types)
Tissues (4 tissue types)
Organs
Organ System (12 organ systems)
Organism

5. Cell Differentiation All of your cells have the exact same
DNA with the exact same information
yet there are 300 types of cells
How do they become different-
heart, lung,skin, etc……?
*Certain genes get turned on while
others get turned off in each of the
different types of cell

7. Homeostasis
Homeostasis- The process by which organisms keep constant/near constant internal conditions despite changes in the external environment
The nervous and endocrine systems are in charge of maintaining homeostasis.

8. Nervous System Function
Body system made up of cells that control and coordinate the other body systems to maintain homeostasis and respond to internal and external condidtions Simplified—It’s the body’s major communication system

9. Neurons
The cells that make up the nervous system are called neurons These cells carry information in the form of electric and chemical signals called nerve impulses Information is electric through the neuron and chemical between Resting potential- no electric signal Action potential- carrying an electric signal

11. 3 types of neurons sensory neurons = senses
nerve cells that gather information and send it to the brain
2) Internerons = interpret information
nerve cells that make up your brain
3) motor neurons = movement
nerve cells that carry messages from the brain to the body for movement

13. Activating the nervous system
Stimuilus- anything that activates a sensory neuron Name the stimulus sensory neurons in eyes- sensory neurons in ears- sensory neurons in body- sensory neurons in nose- sensory neurons in mouth-