Module 3 - neural systems

Question 1

Neuron

Answer 1

• type of cell int he nervous system that communicates with other cells
• most neurons are in the brain (over 80 billion)

Question 2

Soma/cell body

Answer 2

• cells life center
• big circle

Question 3

dendrites

Answer 3

• branches coming out of the soma
• receive messages from other cells

Question 4

axon

Answer 4

• tail that comes out of the body
• carries axon
• has terminal branches and terminal bulbs

Question 5

Neural impulse/action potential

Answer 5

• electrical signal traveling down the axon

Question 6

Myelin sheath

Answer 6

• convers axon of some neurons
  -helps speed up neural impulses

Question 7

terminal branches

Answer 7

• branches at the end of the axon
• have little bulbs at the end called terminal bulbs
• contain vesicles of neurotransmitters

Question 8

How do cells communicate?

Answer 8

• neurotransmitters attach to dendrites at the receptor site and send a positive charge down the axon

Question 9

synapse

Answer 9

• connection point between neurons
• get close but there’s a small gap
• don’t quite touch

Question 10

neuron firing intensities

Answer 10

• neurons have an all or nothing response
• not variation in intensity but firing rates can differ

Question 11

what does it mean for a neuron to fire?

Answer 11

• charge goes above -55 mV and goes up to 40mV
• binary system of communication

Question 12

refractory period

Answer 12

brief dip below resting potential that keeps neuron from firing again right away

Question 13

parts of neural impulse

Answer 13

• resting potential
• threshold (-55ish mV)
• action potential (peak 40mV)
• refractory period

Question 14

excitatory vs inhibitory neural signals

Answer 14

• excitatory drives up the voltage
• inhibitory drives down the voltage

Question 15

examples of neurotransmitters and their function

Answer 15

1. dopamine
   - influences movement, learning, attention, and emotion
   - too much linked to schizophrenia
   - too little linked to tremors and decreased mobility in Parkinson’s
2. serotonin
   - affects mood, hunger, sleep, and arousal
   - undersupply linked to depression
3. endorphins
   - influence perception of pain or pleasure
   - oversupply with opiate drugs can suppress the body’s natural endorphin supply

Question 16

two types of drugs that affect brain chemistry

Answer 16

1. agonist
   - molecule that mimics or increases the activity of a neurotransmitter
2. antagonist
   - molecule that blocks a neurotransmitter’s activity

Question 17

types of neurons

Answer 17

1. sensory/afferent
   - send signals into the CNS
2. motor.efferent neurons
   - send signals out from CNS
3. interneurons
   - send signals within CNS
   - ie. one part of the brain to another

Question 18

reflexes

Answer 18

• don’t really need info from the brain
• ex. touching something hot and pulling away
• hand pulls away before info gets to the brain and causes pain

Question 19

parts of nervous system (flow chart)

Answer 19