1. 1. What is this. 2. How many do you think you have. 3
1.What is this? 2. How many do you think you have? 3. What are the main parts?

2. The Nervous System

3. I. The Nervous System The Nervous System 1. Functions
a. Controls and coordinates functions
throughout the body and responds to
internal and external stimuli
B. Neurons
1. Cells that transmit electrical signals in the
Nervous System, functional unit of nervous system

4. Neuron Factoids
Your brain has as many cells as there are stars in the milky way
Electrical messages in neurons travel about 220 miles/hour
It is not true that you use only 10% of your brain
100 billion neurons

5. Neuron

6. C. Types of neurons:
1. sensory- carry impulses from the sense
organs to the spinal cord and brain.
2. motor- carry impulses from the brain and
spinal cord to muscles and glands.
3. interneurons- connect sensory and motor neurons and carry impulses between them.

7. Structure of Neuron

8. D. Structures of neurons:
1. DENDRITES- carries impulses toward the cell
body.
2. CELL BODY
a. nucleus- control center
c. mitochondria- energy (ATP synthesis)
d. Nissl Bodies- contain rough ER , transport substances, contain ribosomes which make protein
e. neurofibrils- protein filament structures that make-up cytoskeleton

9. 3. AXON- carries impulses away from the cell
body.
a. Schwann cells- accessory cells that make myelin sheath
b. myelin sheath- lipids that cover part of some axons, conducts signal faster
c. nodes of Ranvier- breaks in myelin sheath, leave cell exposed to access ions needed for impulse

10. 4. Terminal End Bulb– at the end of the axon, transmits signals OUT of axon
SYNAPSE- the location at which a neuron can transfer an impulse to another cell. (The gap between neurons)

11. Divisions of the Nervous System-
A. The central nervous system (CNS)- is made up of the brain and the spinal cord.
1. Functions:
a. sends messages
b. processes information
c. analyzes information

12. B. The peripheral nervous system (PNS)- transmits impulses from sense organs to the central nervous system and back to muscles or glands.
1. Afferent/sensory division- sends impulses from the sensory neurons to the
CNS.
2. Efferent/motor division- sends impulses from the CNS to muscles and glands.
a. somatic- control voluntary
actions.
b. autonomic- regulates activities
that are automatic.

14. The Spinal Cord Cross Section of the Spinal Cord Section 35-3
Spinal nerve
Central canal
Gray matter
White matter
Meninges

15. The Senses
A. Sensory receptors- are neurons that react to stimuli in the environment. These receptors send impulses to the central nervous system.
1. 5 types of sensory receptors:
a. pain receptors- respond to pain.
b. thermoreceptors- respond to temperature.
c. mechanoreceptors- respond to pressure.
d. chemoreceptors- respond to chemicals.
e. photoreceptors- respond to light.

16. Figure 35-15 The Ear Section 35-4 Auditory canal Tympanum Round window
Eustachian tube
Bone
Cochlea
Cochlear nerve
Semicircular canals
Oval window
Stirrup
Anvil
Hammer

17. The Senses of Smell and Taste
Section 35-4
Cerebral cortex
Nasal cavity
Taste bud
Smell
sensory area
Taste
Thalamus
Olfactory
(smell) bulb
nerve
Smell receptor
Taste pore
Taste receptor
Sensory
nerve fibers

18. A. The sensory organ responsible for vision is the eye.
1. Pupil- is a small opening at the front of
the eye.
2. retina- contains photoreceptors a. rods- sensitive to light, but don’t distinguish different colors
b. cones- less sensitive to light, but do respond to light of
different colors.

19. Figure 35-14 The Eye Section 35-4 Choroid Retina Blood vessels
Optic nerve
Fovea
Vitreous humor
Sclera
Ligaments
Iris
Pupil
Cornea
Aqueous humor
Lens
Muscle

20. V. Drugs and the Nervous System
A. Drug- any substance, other than food, that changes the structure or function of the body. Several types of drugs affect the nervous system.
1. Stimulants- increase heart rate, blood pressure and breathing rate.
2. Depressants- decrease heart and breathing
rates, lower blood pressure, relax muscles and relieve tension.
3. Opiates- act like natural brain chemicals
(endorphins).

21. Commonly Abused Drugs Section 35-5 Drug Type Stimulants Depressants
Opiates
Used to increase alertness, relieve fatigue
Used to relieve anxiety, irritability, tension
Used to relieve pain
Medical Use
Amphetamines
Barbiturates
Tranquilizers
Morphine
Codeine
Examples
Effects on the body
Increase heart and respiratory rates; elevate blood pressure; dilate pupils; decrease appetite
Slow down the actions of the central nervous system; small amounts cause calmness and relaxation; larger amounts cause slurred speech and impaired judgement
Act as a depressant; cause drowsiness, restlessness, nausea

22. 4. Marijuana- can cause memory and concentration problems.
5. Alcohol- is a depressant that slows down the rate at which the central
nervous system functions.
VI. Drug abuse- is the intentional misuse of
any drug for non-medical
purposes.
A. Addiction- is an uncontrollable dependence on a drug.