Exam 2 Flashcards
1
Q
stressor
A
anything that disrupts homeostasis
2
Q
stress response
what is it
A
physiological and behavioral responses that attempt to reestablish homeostasis
evolved to help with stressor and bring back to homeostasis
3
Q
general adaptation syndrome
A
1 alarm reaction stage
2 resistance stage
3 exhaustion stage
4
Q
what does stress response rely on
A
adrenal gland
5
Q
what is the inside of the adrenal gland called
A
adrenal medulla
6
Q
adrenal medulla
A
made up of modified neurons
inner
secretion of catecholamines
7
Q
what is the outer part of adrenal gland called
A
adrenal cortex
8
Q
adrenal cortex
A
outer
made up of endocrine tissue
secretion of glucocorticoid (steroid hormone)
9
Q
neuroendocrinology of stress response
A
integration of 2 systems
1 sympathetic branch of autonomic nervous system
2 HPA axis- endocrine
10
Q
1 alarm reaction stage
A
activated within seconds of stressor appearing
catecholamine secretion
fast acting
“fight or flight” response
11
Q
what catecholamines are secreted with alarm reaction stage
A
1 norepinephrine
2 epinephrine
12
Q
1 norepinephrine
from where
A
from adrenergic neurons throughout body
13
Q
2 epinephrine
from where
A
from adrenal medulla derived from tyrosine
14
Q
what does the sympathetic branch release
A
catecholamine
15
Q
what does the HPA axis release
A
glucocorticoid
cortisol
corticosterone
16
Q
what are additional hormones secreted when stress response is activated
A
1 beta- endorphins
2 vasopressin
3 prolactin
17
Q
1 beta endorphins
function
A
pain suppresion
18
Q
2 vasopressin
function
A
increases blood pressure
19
Q
3 prolactin
function
A
unclear function
20
Q
catecholamine functions
7
A
have a variety of effectors
1 increase blood glucose levels
2 increase alertness and memory retention
3 increase oxygen intake
4 increase free fatty acids
5 increase blood flow to muscles used in movement
6 increase HR and BP
7 inhibition of digestion and pain perception
21
Q
2 resistance stage
A
activated within minutes to hours; if stressor continues
activation of hypothalamic pituitary adrenal axis
22
Q
HPA axis
hypothalamic pituitary adrenal axis
A
stressor hypothalamus secretes corticotropin releasing hormone (CRH) travels to anterior pituitary secretes adrenocorticotropic hormone (ACTH) travels to adrenal gland adrenal cortex secretes glucocorticoids which includes cortisol, corticosterone
23
Q
what are the target tissues for glucocorticoids that are secreted
A
liver, skeletal muscle
24
Q
what happens when glucocorticoids reach appropriate level
A
negative feedback at hypothalamus and anterior pituitary
25
glucocorticoids
what are they
how is it moved through blood
what kind of receptors
corticosterone and cortisol (steroids)
moved through blood via carrier
intracellular receptors
26
what moves corticosterone and cortisol through blood
corticosterone binding globulin (CBG)
27
what happens when hormone binds to receptor
| glucocorticoids
hormone binds to receptor
receptor hormone complex activates or suppresses gene transcription
alteration of protein leads to response
has variety of effects in the body
28
glucocorticoid effects
| 3
1 increase blood glucose
2 breakdown of protein and fats
3 suppress immune response and inflammation, reproduction, digestion
all these effects evolved to promote escape from stressor
29
what does increased blood glucose do in the stress response
induction of gluconeogenesis
| reduction of cellular glucose uptake
30
3 exhaustion stage
if stressor continues for days, weeks, months, or years
long term or repeated
continued secretion of epinephrine, norepinephrine, and cortisol
( we did not evolve for this kind of thing, creates "wear and tear" on the body)
31
what kind of stress is alarm reaction and resistance stages
acute stress
32
what kind of stress is exhaustion stage
chronic stress
33
what are effects of acute stress 6
```
increased energy
increased cardiac output
inhibited digestion
inhibited reproduction
immunosuppression
enhanced cognition
```
34
what are effects of chronic stress
| 6
```
fatigue, myopathy
hypertension
ulcers
infertility
loss of disease resistance
neural degeneration
```
35
physical vs psychosocial stress response
we initiate stress response for psychosocial situations
same hormones secreted
same effects on body
but the stress response evolved for physical stress not psychosocial
36
parts of neuron
```
1 cell body
2 axon hillock
3 axon
4 axon terminal
5 dendrites
```
37
1 cell body
location of nucleus and organelles
38
2 axon hillock
where action potential or signal generated
| high number of Na+ channels
39
3 axon
carries action potential
40
4 axon terminal
release of neurotransmitters
| communication with other neurons/effectors
41
5 dendrites
where neurotransmitters bind from other neurons receive signals from other neurons
42
resting membrane potential
voltage (charge) difference across cell membrane when cell is at rest
slightly negative
43
what is resting membrane potential due to
gradient of Na+ and K+ between intracellular and extracellular environment
cell membrane is more permeable to K+ than Na+ leads to K+ leaking out
44
action potential
temporary reversal of voltage (charge) inside of the cell
voltage within cell becomes temporarily positive
"signal firing"
45
steps to an AP graph
```
1 RMP- all channels closed, Na+ and K+
2 depolarization
3 repolarization
4 hyperpolarization
5 return to RMP
```
46
2 depolarization
Na+ channels open, Na+ rushes into cell, K+ channels closed
47
3 repolarization
Na+ channels closed, K+ channels open
| K+ rushes out of cell
48
4 hyperpolarization
"overshoot" K+ rushes out
49
all or none principle
threshold must be reached to generate AP
if stimulus is able to depolarize the membrane to reach threshold, all the steps that lead to AP will happen without stopping
50
graded potentials
changes in membrane potential that vary with stimulus strength
can be summed to increase overall strength
51
what happens if graded membrane potential is strong enough
threshold may be passed and changed to AP
52
where do graded potentials occur
conducted only locally and then dies out (rather than propagating all along axon like AP
53
action potential propagation
a single AP involves only a small portion of plasma membrane but it propagates because each AP stimulates an AP in an adjacent area
54
where does propagation occur
from axon hillock to axon terminal
| only goes in one direction
55
refractory period
unidirectional AP propagation due to refractory period
| period of time where a cell is unable to generate another AP
56
what causes a refractory period
temporary inactivation of Na+ channels
57
1 absolute refractory period
interval of time where an AP cannot be generated no matter how large the stimulus
58
2 relative refractory period
interval of time where another AP "could" be initiated, but would require a greater stimulus
59
strength of signal
stronger signal result in a greater frequency of APs (not larger APs)
60
neural tissue
neuron
| neuroglia
61
neuron
| function
generate, send and receive neural signals
62
neuroglia
| function
support and protection of neuron
| myelin sheaths that surround axons of some neurons
63
transmission of neural signal
AP always propagates towards axon terminals
64
myelin sheath
surround axon
65
nodes of Ranvier
gaps between myelin sheath
66
neuroglia
| types
```
oligodendrocyte (CNS)
Schwann cell (PNS)
```
67
myelin is
lipid-rich and insulates axon, whitish
68
what does myelination of an axon do
speeds up AP conduction
69
saltatory conduction
from one node of Ranvier to the next one "jumps"
| AP only occur at NoR
70
what is concentrated at NoR
voltage gated Na+ and K+ channels
71
do myelinated regions have Na+ and K+ channels
have almost none
72
where do unmyelinated axons have Na+ and K+ channels
along its length, no saltatory conduction, slower progagation
73
myelination and AP conduction speed
faster conduction in myelinated axons
| thick myelin sheath means faster conduciton
74
axon diameter and AP conduction speed
greater axon diameter means faster conduction
| greater surface area for Na+ channels
76
synapse
junction between 2 cells
77
types of synapse
neuron and neuron
| neuron and effector (muscle or gland)
78
what does the presynaptic neuron do
send signal
79
what does the post synaptic neuron do
receives signal
80
1 electrical communication
gap junctions
| allows ions to flow directly from one cell to another
81
what forms gap junction
connexons channels
82
2 chemical communcation
very common
| conduct signal via neurotransmittors
83
neurotransmitters
| 6 types
```
1 acetylcholine
2 monoamines
3 amino acids- GABA
4 purines
5 neuropeptides
6 gases
```
84
types of chatecholamines
epinephrine
norepinephrine
dopamine
85
steps of NT release
1 AP arrives at the axon terminal
2 this causes voltage gated Ca++ channels to open, causing Ca++ to rush in
3 influx of Ca++ causes vesicles with Ach to release Ach into the synaptic cleft
4 Ach diffuses across the cleft
5 Ach binds to ligand gated Na+ channels on PSN
6 Na+ rushes into PSN which causes depolarization of PSN
86
responses to NTs: Excitatory vs Inhibitory post synaptic potential
what does it depend on
responses to PSN to a NT depends on NT secreted and receptors on PSN
87
excitatory PSP (EPSP)
results in depolarization of PSN due to influx of Na+
| stimulatory/excitatory effect on PSN
88
inhibitory PSP (IPSP)
results in hyperpolarization of PSN due to influx of Cl- or efflux of K+
inhibitory effect on PSN
89
regulation of NT levels
rapid NT removal from cleft
NT must be inactivated or removed from the cleft for PSN to receive additional signals
reuptake proteins on PrSN axon terminal bring NTs back for breakdown and recycling
90
what does acetylcholinesterase breakdown
acetycholamine
91
what does monoamine oxidase breakdown
monoamines
92
blockage of NT uptake (drugs)
SSRIs
widely used as antidepressants and anxiety
blocks reuptake of serotonin which causes serotonin to spend more time in the cleft which means its able to produce longer lasting effects
93
other influences on neurons
neuromodulator
| axoaxonic synapse
94
neuromodulator
do not cause EPSP or IPSP
| instead depress or enhance effects of NTs
95
axoaxonic synapse
axon of neuron synapses with presynaptic neuron of another neuron
increase or decrease release of NT
96
summation of signals
graded potential summate at the trigger zone (axon hillock)
| must reach threshold to propagate (AP) along axon
97
1 spatial summation
multiple stimuli at different spots
98
2 temporal summation
multiple stimuli at different times
99
grand postsynaptic potential (GPSP)
add all signals together to get a response
100
neural circuits
| what is it
neurons linked through complex pathways
101
1 convergent neural circuit
a single neuron that has many other neurons synapsing on it
102
2 divergent neural circuit
axon has many branches of its terminals so it influences many other neurons
103
reflex
involuntary response to stimulation, homeostatic,
104
what is the goal of autonomic reflex
maintain BP
105
what is the goal of somatic reflex
moving away from a painful stimulus
106
reflex arc
basic functional unit of nervous system
107
pathway of reflex arc
reception of signal
| production of response
108
receptor
detects stimulus
109
sensory/afferent neuron
conducts AP to CNS
110
interneuron
relays signal to motor neuron
111
motor/efferent neuron
conducts AP to effector
112
effector
carries out response
113
reflex arc varies in complexity
monosynaptic reflex arc
| polysynaptic reflex arc
114
monosynaptic reflex arc
sensory neuron synapses directly with motor neuron
115
example of monosynaptic reflex arc
patellar reflex
116
polysynaptic reflex arc
involves interneuron within spinal cord
117
stretch reflex
contraction of muscle in response to stretch
118
patellar reflex
1 receptor- muscle stretch detected by muscle spindle, responds to stretch of quads
2 sensory neuron- carries signal to spinal cord
3 alpha motor neuron- sensory neuron synapses directly with alpha motor neuron, rapid contraction of opposing original stretch initiated
4 effector- quads
119
muscle spindle
bundle of skeletal muscle fibers
120
responses of reflex arc
excitatory
| inhibitory
121
excitatory reflex arc response
muscle contraction
122
inhibitory reflex arc response
muscle relaxes
123
signal integration
ascending tracts within spinal cord carries signal to brain
descending tracts modify reaction
gamma motor neuron
124
gamma motor neuron
transmission from spinal cord
| regulates sensitivity of muscle spindle
125
withdrawl reflex
removal of limb from painful stimulus
reciprocal innervation- excitatory interneurons, contraction of flexor muscles, inhibitory interneurons- relaxation of extensor muscles
