Nervous System

Question 1

types of CNS synapses

Answer 1

axo-dendritic (most common): nerve A axon to nerve B dendrite
axo-somatic: nerve A axon to nerve B soma (cell body)
axo-axonic: nerve A axon to nerve B axon
dendro-dendritic: nerve A dendrite to nerve B dendrite

Question 2

sensory neurons

Answer 2

-specialized cells or nerve endings located throughout the body
-detect and process sensory information
-afferent

Question 3

order of information movement in CNS

Answer 3

1. spinal cord
2. pons and mesencephalon
3. cerebellum
4. thalamus
5. cerebral cortex

Question 4

the motor system controls…

Answer 4

-skeletal and smooth muscle
-secretion of active chemicals by exocrine & endocrine glands

Question 5

integrative functioning

Answer 5

channelling and processing of information

Question 6

communication role of synapses

Answer 6

amplify or dampen signals
integrate inputs from multiple neurons
shape the overall output of the postsynaptic neuron

Question 7

functions of the spinal cord

Answer 7

-conduit for information
-spinal reflex arcs
-sensory integration
-proprioception
-basic locomotion

Question 8

functions of the subcortical brain

Answer 8

-regulate fundamental physiological processes
-emotional responses
-motor control
-maintain overall homeostasis & survival

Question 9

areas of the subcortical brain

Answer 9

medulla
pons
mesencephalon
hypothalamus
thalamus
cerebellum
basal ganglia

Question 10

functions of the cortical brain

Answer 10

-wide range of cognitive functions
-sensory processing
-motor control
-memory
-language
-higher order thinking
-complex mental abilities and conscious

Question 11

actions on nerve impulses

Answer 11

-blocked in transmission
-changed to repetitive impulses
-integrated with impulses from other neurons

Question 12

chemical synapse

Answer 12

-no direct physical connection between pre and post-synaptic neurons
-neurotransmitters act on the post-synaptic neuron
-transmitter vesicles and mitochondria are key
-one-way conduction from pre to post-synaptic

Question 13

excitatory NTs

Answer 13

glutamate
histamine

Question 14

inhibitory NTs

Answer 14

GABA
serotonin

Question 15

modulatory NTs

Answer 15

acetylcholine
dopamine
norepinephrine

Question 16

electrical synapse

Answer 16

direct physical contact (gap junction) between the pre and post-synaptic neurons

Question 17

action at synapse

Answer 17

-depolarization from action potential
-voltage-gated Ca++ channels open
-Ca++ enters the pre-synaptic neuron
-synaptic vesicles fuse
-NT is released

Question 18

cation

Answer 18

positively charged ion
-usually Na+, sometimes K+ or Ca++

Question 19

anion

Answer 19

negatively charged ion
-mainly Cl-

Question 20

ionotropic receptors

Answer 20

activated receptors that are ion channels

Question 21

metabotropic receptors

Answer 21

G-protein and/or second messenger involved

Question 22

second messenger

Answer 22

inside the postsynaptic neuronal cell causing a prolonged effect or excitation or inhibition

Question 23

excitation

Answer 23

increase Na+ conduction through channels
decrease K+ conduction through channels

Question 24

inhibition

Answer 24

increase Cl- ions into the neuron
increase K+ ions out of the neuron

Question 25

chemicals that function as synaptic transmitters

Answer 25

-small molecule, rapidly acting transmitters: Ach, NE, Epi, Dopa, GABA, ATP, NO, CO -neuropeptides (slow acting & more potent): luteinizing hormone, growth hormone, oxytocin, substance P, insulin, glucagon, vasopressin

Question 26

important small molecule transmitters

Answer 26

Ach: secreted by neurons in many areas, mostly excitatory, inhibits vagus nerve NE: secreted by neurons w/cell bodies in the brain stem and hypothalamus, increases wakefulness Dopa: secreted by neurons originated in substantial nigra, usually inhibitory Glycine: secreted mainly in spinal cord, inhibitory GABA: primary inhibitory NT in CNS Glutamate: likely always causes excitation Serotonin: inhibitor of pain pathways in the cord, controls mood

Question 27

presynaptic inhibition

Answer 27

inhibitory neuron provides synaptic input to the axon of another neuron ( less likely to fire an AP)

Question 28

synaptic transmission fatigue

Answer 28

a synapse becomes less effective at transmitting signals over time (mainly exhaustive stores of transmitters)

Question 29

alkalosis & synaptic transmission

Answer 29

-greatly increases neuronal excitability -can lead to cerebral epileptic seizures

Question 30

acidosis & synaptic transmission

Answer 30

-greatly depresses neuronal activity -causes a comatose state -ex: DKA or uremic acidosis

Question 31

hypoxia & synaptic transmission

Answer 31

-can cause complete in-excitability of some neurons -3-7 seconds patient becomes unconscious

Question 32

drugs & synaptic transmission

Answer 32

increase excitability: caffeine, theophylline, theobromine increase TP: many anesthetics

Question 33

synaptic delay

Answer 33

brief time lapse between the arrival of an AP and the initiations of postsynaptic response