Nervous System IV

Question 1

Nerve Impulse Direction

Answer 1

Impulse travels forward along the axon because the previous segment is still in it’s refractory period

Question 2

Acetylcholine

Answer 2

Neurotransmitter at the neuro muscular junction. Little chemical that moves across the synapse to bind to the acceptor.

Example of a NT (chemical messenger that bridges the synapse)

Question 3

Acetylcholinesterase

Answer 3

An enzyme that breaks down acetylcholine in the synaptic cleft so depolarization is not a continuous event.

Question 4

Excitatory Post Synaptic Potential (EPSP)

Answer 4

Graded depolarization of post synaptic membrane by the arrival of a NT.

Question 5

Inhibitory Post Synaptic Potential

Answer 5

makes a postsynaptic neuron less likely to generate an action potential

Ex: GABA

Question 6

GABA

Answer 6

Binds to Potassium Gate

Question 7

Catecholamines

Answer 7

Also a neurotransmitter. Work with a secondary messenger to depolarize membrane.

Ex: Epinephrine, norepinephrine, dopamine

Question 8

Depolarization with a Secondary Messenger

Answer 8

1. Action potential depolarizes synaptic knob
2. Calcium enters axoplasm triggering norepinephrine release into synaptic cleft (1st messenger)
3. norepinephrine binds to receptor site causing AC (Adenyl Cyclase) with in cytoplasm to catalyze formation of cyclic AMP from ATP
4. cyclic AMP (2nd messenger) opens ion channels allowing sodium to depolarize membrane

Question 9

Summation

Answer 9

Integration of EPSP’s and IPSP’s to reach depolarization threshold.

Question 10

How much mV will EPSP produce local depolarization?

Answer 10

.5 mV when action potential may require -15 to -20 mV charge to reach depolarization threshold.

Question 11

Two ways for EPSP to Reach Depolarization Threshold?

Answer 11

Temporal Summation and Spatial Summation

Question 12

Temporal Summation

Answer 12

Same location, different time - a stimuli occurring in rapid succession at the same synaptic knob. Close enough together to eventually reach summation.

Question 13

Spatial Summation

Answer 13

Same time, different location - stimuli arriving at the same time at different locations in loose proximity. Enough local depolarization.

Question 14

Adaptation

Answer 14

Reduction of sensitivity in the constant presence of a stimulus. In general our body gets use to it.

Question 15

Neural Interaction

Answer 15

Patterns of neuronal interaction

Question 16

Convergence

Answer 16

Several neurons synapsing on same post synaptic neuron…multiple neurons firing on one nerve

Question 17

Divergence

Answer 17

Spread of one neurons info to several neurons

Question 18

Serial Processing

Answer 18

Neurons lined up in a sequential manner

Question 19

Receptor

Answer 19

A specialized cell that monitors conditions or receives info from the body or external environment.

Question 20

What does receptor do?

Answer 20

Receives sensory information, sends it to the CNS, Monitors pain, touch, body position, proprioreception.

Question 21

Effector

Answer 21

Peripheral gland or muscle innervated by a motor nerve. (Efferent Neuron). Causes some type of activity. Something to happen.

Question 22

Spinal Cord

Answer 22

Extension of the CNS that travels down the spinal canal. But only goes to the L1 Vertebral level. Doesn’t go down to Sacrum.

Question 23

At what age does Spinal cord stop growing?

Answer 23

At age 4

Question 24

Spinal Nerves exit what?

Answer 24

Intervertebral Foramen

Question 25

Spinal Cord stops at what Level?

Answer 25

L1

Question 26

Cauda Equina

Answer 26

Horses Tail, spinal nerves at the end of L1

Question 27

Cone Shape at the End of the Spinal Cord

Answer 27

Conas Medullaris

Question 28

Cord coming off of the Conas Medullaris

Answer 28

Filum Terminale

Question 29

Filum Terminale

Answer 29

Made up of Pia Mater. Tethers the end of the cord to the sacrum.

Question 30

Pia Mater

Answer 30

Meningeal Coverings. Delicate that is highly vascular and follows the convolutions that clings close to the surface of the brain.