1. The Nervous System

2. Nervous System
Nervous System: Collects information, processes, and responds to internal and external environment

3. Overview of Nervous System
Stimulus: Something in environment causes a response
Neuron: Cell that receive, conduct, and transmit impulses
Response: Reaction to environmental conditions
synapse
RESPONSE!

4. The Neuron
Neurons build into nerves!

5. Parts of the Neuron Dendrites Receive messages from previous neurons
Send message to cell body
Cell Body
Contains nucleus and cytoplasm

6. Parts of the Neuron: Cont’d
Axon
Long fiber that carries messages away from the cell body
Myelin Sheath
Insulating membrane helps send the signal down the axon
Nodes of Ranvier
Gaps between Schwann Cells
Impulse jumps from one node to next
Schwann Cells
Supporting cells that wrap around the myelin sheath

7. Parts of the Neuron: Cont’d
Axon Terminals
Branches at the end of an axon
Contain synapses where neurotransmitters are released

8. Synapses Synapse Space between neurons
Carry messages or impulses from one nerve to the next
Neurotransmitters
Chemical messages sent between neurons
Diffuse to next neuron

9. How does a neuron work? Summary
Neurotransmitter received from another neuron in dendrites & through cell body
Impulse travels down the axon
Neurotransmitter released into synapse
Neurotransmitter received by protein receptors in dendrites of next neuron

10. A closer look at how an impulse travels down the axon
Polarization- differences in charge ( + or -)
Electrical charges are different inside a neuron compared to outside
Caused by K+ and Na+
K+ and Na+ can move through channels within the axon membrane

11. A closer look at how an impulse travels down the axon
Impulse is carried down the axon
Resting
Negative inside (-70 mV)
Active- Impulse in progress
Positive inside (+40 mV)

12. How does a neuron work?

13. Receptor & Sensory Neurons
Types of Neurons
Motor Neuron
(Spinal Cord and Brain  Muscles and Glands)
Receptor & Sensory Neurons
(Sensory Organs Spinal Cord and Brain)
Interneurons
Sends Messages between Nerves (Sensory, Receptor, Motor, and other Interneurons)

14. Reflex Arc No brain involved! Receptor Afferent Neurons Sensory Neuron
Spinal Cord
Interneuron
Efferent
Neurons
Motor Neuron
Effector
(Muscle)

15. Central Nervous System (CNS)
Consists of the brain and spinal column

16. Spinal Cord Gray Matter White Matter Consists of cell bodies
Consists of axons

17. Parts of the Brain
Meninges- protective covering of the brain/spinal cord
Corpus
Collasum
Occipital

18. Brain Area Function Meninges Protection of spinal cord and brain
Cerebrum
Memory center
Cerebellum
Coordination and balance
Medulla
Involuntary processes
Spinal Cord
Nerves from brain
Thalamus
Relay center between brain and spinal cord
Occipital
Vision & Hearing
Hypothalamus
Homeostasis- hunger, thirst, hormones
Links endocrine to nervous system
Corpus Collasum
Connects left and right brain

19. Peripheral Nervous System
Peripheral Nervous System- connects the central nervous system to the rest of the body
Somatic- voluntary
Autonomic- involuntary
Parasympathetic- at rest
Sympathetic- fight or flight

20. Malfunctions Meningitis- swelling of meninges
Cerebral Palsy- birth defect, affects muscle coordination
Stroke- blood clot to the brain
Polio- viral illness
Multiple sclerosis (MS)- break down of myelin sheath- impairs movement

21. Malfunctions Drug Addictions Stimulants Depressants
Increase the number of neurotransmitters
Depressants
Decrease the number of neurotransmitters