Human Phys Exam 3 Flashcards
1
Q
what is the central nervous system composed of?
A
brain, spinal cord
2
Q
what are the pathways within the peripheral nervous system
A
afferent and efferent pathways
3
Q
difference betweeen afferent and efferent pathways?
A
afferent: go toward CNS
efferent: send info from CNS
4
Q
what are the two systems within the efferent pathways?
A
autonomic and somatic nervous system
5
Q
difference between autonomic and somatic nervous systems?
A
autonomic: symathetic (excitatory) division, paraympathetic (inhibiotry) division
somatic: stimulates skeletal muscle contraction
6
Q
what are afferent neurons
A
originiate in the periphery of the body via a sesory or visceral receptor and travel toward CNS
7
Q
what are efferent neurons
A
originate in CNS and travel to periphery to produce an effect in the body (efferent neurons towards effector organ)
8
Q
what are interneurons
A
found in CNS, allow communication btw afferent and efferent neurons
9
Q
what are excitable cells
A
cell that can produce electrical signals
10
Q
what are action potentials
A
electrical signals produced by excictable cells
11
Q
what are neurons
A
excitable cells in the nervous system
12
Q
what are glial cells
A
structural cells found in the nervous system, pack and keep cells together (90% of cells)
13
Q
what is the basic structure of a neruon?
A
cell body, dendrites, axon, axon terminal
14
Q
what is myelination? effect?
A
- due to Schwann cells wrapping around axon, creates myelin sheath that acts as insulation
- myelination increases conduction velocity of nerve impulse
15
Q
what is the membrane potential?
A
electrical potential difference are created in excitable cells by separating oppositely charged ions
16
Q
what is the resting membrane potiental
A
-70mv
17
Q
how does depolarization occur?
A
when an excitable cells membrane permeability is altered, the membrane potiental changes
-spread of depolarization is called an action potential
18
Q
what is the resting membrane potential crated from?
A
K+ leaking out of the cell faster than Na+ leak into the cell (3 Na pumped out, 2K pumped in)
19
Q
depolarization refers to?
A
a change in the membrane potiental from its resting negative value to a more positive value
20
Q
where are gated ion channels found?
A
dendrites, cell body, axon hilock region of a neuron
21
Q
what activates gated ion channels?
A
volatage changes, ligand/recetpor interactions, mechanical stimulation
22
Q
what are voltage gated cahnnels?
A
open with change in voltage in axon hilock, getting shocked, action potentials
23
Q
what are ligand gated channels?
A
open due to binding of ligand to membrane recetpor in dendrites, neurotransmitter from another neuron binds to a receptor
24
Q
what are mechanically gated channels?
A
open due to mechanical stimuli on dendrite or cell body
-pressure, force
25
what is hyperpolarization?
if the membrane potiental becomes more negatiave
26
what is repolarization?
a return to the rsting membrane potiental
27
what are graded potientals?
small changes in the membrane potential due to ion channels opening or closing following stimulation by another source
28
when do graded potientails create action potentials?
if they change membrane potential above threshold
29
if depolarization occurs these are called ______, if hyperpolarzation occurs ______
excitatory graded potentials, inhibitory graded potentials
30
the graded potential sends a stiumulus to the axon hillock but it has to be strong enough so the axon hillock can reach a threshold at ___
-55mv
31
what are the phases of an action potential?
depolarization, repolarization, after hyperpolarization
32
what is the all or none principle
if membrane potential goes above threshold an action potential is produced that is always the same magnitude
33
can a stimulues generate a second action potnetial during the absolute refractory period
no
34
what is the refractory period
when the membrane is less excitable than at rest
35
explain action potentials in unmyelinated axons
- action potential propagates down an axon
- pos charges move from the area that has been depolarized to the adhacent area on the membrane
- current flows to adhacent areas based on electronic conduction
36
do larger or smaller diameter axons have faster conduction velocities?
larger diameter axons
| -have less resistance to current flow down axon
37
how do ions propagate down the axon?
the sites enter a refractory state after it is depolarized
38
explain action potentials in myelinated axons
- saltatory conduction is used to propagate action potentials
- action potentials cannot be produced ina reas where myelin is present so the current flows from node to node very quickly
- fastest conduction velocities are found in large diameter myelinated axons
39
what happens at the synaptic transmission?
the action potential reaches the axon terminal which stimulates vesicular movement to terminal membrane by opening Ca channels
-neurotransmitter diffuses to postsynaptic memebrane and binds to receptors
40
what are excitatory synapses?
bring postsynaptic neurons closer to thershold for AP to occur
-depolarization is called an excitatory postsynaptic potential
41
what is the difference between a fast and slow excitatory respose?
fast excitatory response is when a neurotransmitter opens ion channels allowing for a rapid depolarization
-slow is when a neurotransmitter activates a Gprotein/2nd messenger cascade that is slower to create a depolarizaiton
42
what do inhibitory synapses cause?
causes postsynaptic neuron membrane potentials to be hyperpolarized or stabilized
-IPSP
43
what is convergence summation?
when a number of presynaptic neurons synapse on one postsynaptic neuron
44
what is temporal summation?
when 2+ postsynaptic potentials are produced in rapid succession at the same synapse and are additive to create a greater depolarization
45
what is spacial summation
2+ postsynaptic potentials from different synapses overlap are are additive
46
what are modulatory synapses
regulate communication across another synapse
47
what are axoxaxonic synapses
form btw axon terminals of 2 diff neurons, modulatory synapses
-neurotransmittor induces a change in the amount of Ca that enters the axon terminal in response to an action potential
48
what is presynaptic facilitation?
increaes releases of neurotransmitter from the postsynaptic neuron
49
what is presynaptic inhibition?
decreases release of neurotransmitter form postsynaptic neuron
50
what are the different classes of neurotransmitters?
choline derivative, biogenic amines, amino acids, neuropeptides, others
51
what is the choline derivative neurotransmitter?
acetylcholine
- released from neruons in CNS,PNS
- produced from acetyl coA and choline
- binds to cholinergic recpetors
52
what enzyme coverges acetly coa and choline?
choline acetyl transferase
53
what are the 2 types of cholinergic receptors
nicotinic and msucarinic
54
what are nicotinic cholinergic receptors?
Ach binding to nicotinic receptors causes opening of Na and K channels causing EPSP
- found in PNS
- muscle cells, autonomic neurons
55
what are muscarinic cholinergic receptors?
- metabotropic
- works via 2nd messenger system in postsynaptic cell
- main receptor in CNS and found on effector organs in body to cause an inhibiting effect
56
what are the neurotransmitter that are biogenic amines?
catecholamines, serotonin, histamine
| -all have an amine group and dervied from amino acids
57
what are catecholamines?
epinephrine, norepinephrine, dopamine
58
what are the receptors for EPI, NE and dopamine?
epi and ne: adrenergic
| dopamine: dopaminergic
59
what are the 2 main classes of adrenergic receptors
alpha and beta
- epi: high affinity beta2
- ne: alpha and beta1
60
what 2 enzymes degrade catecholamines?
monoamine oxidase and catechol O methyltransferase
| -occurs at synapses
61
what degradation of catecholamines can be inhibited?
monoamine oxidase can be inhibited, reuptake molecule cannot
62
where in the CNS is serotonin found?
brainstem
| -regulating sleep and emotions
63
where in the CNS is is histamine found
hypothalmus
64
what does the monoamise oxidase enzyme do?
breaksdown neurotransmitter after it has been released so it doesnt stay in the stimulus too long and over stimulate the postsynaptic neuron
65
what is the effect of the monoamine oxidase inhibitor?
use the drug to inhibit the monoamise oxidase enzyme to create a greater effect
66
whats an example of a reuptake moleucle inhibitor?
SSRI, more serotonin in the synapse so theres a greater response, helps with production of serotonin
67
what are the amino acid neurotransmitters?
glutamate, aspartate, GABA, glycine
68
which amino acids are excitatory? inhibitory?
excitatory: glutamate, asparate (more likely to have an action potential in postsynaptic neuron
inhibitory: GABA, glycine
69
what is an example of when an excitatory aa being used
when you get hot glutamate and aspartate would be realsed to stimulate the hypothalms to tell the sweat glands to sweat
70
what are neuropeptides?
short chains or AAs that are found in neurons and likely function as neurotransmitters and hormones
71
what are other chemical substances that function as neurotransmitters?
nitric oxide and ATP
72
what fluid makes up the central nervous system?
cerebrospinal fluid, similar composition to plasma (IF)
73
what percent of blood pumped by the heart is recieved to the CNS?
15%, due to high metabolism
74
what percent of O2 and glucose does the brain consumed?
o2: 20
glucose: 50
75
what is not produced in the CNS?
glycogen not stored, fatty acids, cant produce energy anaerobically
76
what is the bloodbrain barrier?
- protects CNS from harmful substances
- o2, glucose and other materials exchange through the capillaries
- formed by tight junctions btw endothelial cells of cerebral capillaires
77
why is gluclose and proteins less in CSF compared to plasma?
CSF uses gluclose immediately and lower proteins bc they are restricted from entering the blood within the brain
78
what are the 3 parts of the brain
forebrain, cerebellum, brain stem
79
what is the forebrain consist of?
right/left hemispheres
| -cerebrum and cerebral cortex
80
what is the cerebrum
contains the cerebral cortex (surface) and subcortical nuclei (deeper)
81
what happens in the cerebral cortex?
carries out highest level of neural processing: perceptions, ideas, memory, motor control
-integrating center that recieves and processes sensory info to formulate thoughts and actions
82
what does the diencephalon contain?
thalamus and hypothalamus
83
what does the thalamus do?
filters and refines sensory info before it reaches the cerebral cortex, involved in motor movement control
84
what does the hypothalamus do?
releases tropic hormones to anterior pituitary and controls posterior pituitary hormone release
- produces hunger and thirst and inolved in emotions
- regulates body temp
85
what does the cerebellum do?
- inferior to the forebrain and posterior to brainstem
| - motor coordination balance and procide feedback to produce smooth motor movements
86
what does the brainstem do and include?
- connects cerebrum and cerebellum to spinal cord
| - 3 regions: midbrain, pons, medulla oblongata
87
what autonomic functions does the brainstem regulate
cardiovascular and respiratory control
88
what does the brainstem control?
- sleep wake cycles, consciousness, arousal of the cerebral cortex via retiuclar formation
- process cranial nerve info
89
what are the functional areas of the cerebral cortex?
- primary motor cortex
- premotor cortex
- central sulcus
- primary somatosensory and cortex
- sensory association areas
- visual association areas
- primary visual cortex
- wernickes area
- auditory association areas
- primary aduitory cortex
- limbic association cortex
- olfactory cortex
- brocas area
- prefrontal association areas
90
what does the limbic system do? different areas?
- collection of areats that function in learning and emotions, controls basic drives
- areas: amygdala, hippocampus, fornix, cingulate gyrus, hypothalamus, thalamus
91
what processes make up voluntary motor control?
1. idea or intention to move
2. development of a program of motor commands
3. execution of the program of motor commands
4. continual feedback to assess and refine the movement
92
how does the cerebellum help voluntary movements?
functions to correct movements as they occurs, maintain muscle tone, and store info to allow for enhanced coordination of a movement with practice
93
how are emotions produced?
sensory input and memories
94
stimuli from both the internal and external environments are detected by
sensory receptots
95
what are external stimuli detected by?
somatosensory system (skin), proprioceptors(limb position/motion), special sensory ( vision, smell, taste, hearing, balance, equlibrium) system
96
what are internal stimuli detected by?
visceral receptors that transmit signals to the CNS via visceral afferents
97
what do receptors in the somatosensory system respond to?
pressure, pain, temp, body position
98
what do mechanoreceptors respond to?
pressure, force, vibration
99
what do thermoreceptors respond to?
temperature
100
waht do nociceptors respond to?
injurious stimuli (pain)
101
what are modalitiy for mochanoreceptors?
light touch, pressure, vibration, bending of hair, pressure
102
what are modalities for thermorecptors?
increase in skin temp, decrease in skin temp
103
what are modalities for nociceptors?
intesne mechanical stimulus, intense hot or cold stimulus, intense mechanical or thermal stimulus, specific chems
104
what is the difference between fast and slow pain?
fast pain: sharp, pricking, well localized
| slow: dull, aching, poorly localized, general
105
what is visceral pain
detected by nociceptors that are stimulated by tissue damage in internal strucutures
-heart, lungs, live, GI
106
what is referred pain
result of visceral pain
| -occurs due to second order neurons reciving signals from somatic afferents along the visceral afferent
107
what is the gate control theory of pain
inhibitory interneurons in the spinal cord stimulated by skin mechanorecptors can inhibit the 2nd orderneurons in the spinal cord that transmit pain info (rubbing skin)
108
what is the endogenous analgesia system
neurotransmitter enkephalin is released from inhibitoy interneurons to inhibit synaptic transmission from the nociceptive afferent to the 2nd order neuron
