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Physiology > Exam Three: Learning Objectives > Flashcards

Exam Three: Learning Objectives Flashcards

1
Q

What are the two broad types of synapes?

A

Chemical and electrical

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2
Q

Chemical synapses are __ and electrical synapses are __

A

complex, simple

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3
Q

Describe the current flow at a chemical synapse.

A

flows our of presynaptic cell and spac e in between presynaptic and postsynaptic cell

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4
Q

Describe the current flow at an electrical synapse.

A

Current flows out of the presynaptic cells and through the gap junction to continue out of the post synaptic cell

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5
Q

Electrical synapses: relatively __ action, almost always __. Present where __ and __ are paramount. Present in circuits that control __ __ or _

A

simple; excitatory
speed; synchronization
rapid behaviors; responses

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6
Q

Describe step one: arrival of action potential at terminal

A

arrival of the AP at terminal stimulates the opening of voltage-gated Ca channels, which results in the influx of Ca into the cytosol from outside of the cell, takes place in the presynaptic cell

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7
Q

Describe step two: Ca triggers vesicle fusion and neurotransmitter release

A

increased cytosolic Ca activates vesicle fusion and exocytosis of synaptic vesicles

prior to ca activation, the synaptic vesicles are already docked at the active zones filled with neurotransmitter

The neurotransmitter molecules begin to diffuse across the synaptic cleft towards the post-synaptic membrane

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8
Q

Describe step three: neurotransmitter binds to post-synaptic receptor

A

neurotransmitters diffuse across the cleft and bind to specific receptors on the post-synaptic membrane of the effector cell

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9
Q

What are the two steps that can result from the neurotransmitter binding to a post-synaptic receptor?

A

fast chemical synaptic transmission
slow chemical synaptic transmission

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10
Q

Describe the fast chemical synaptic transmission

A

binding to ionotropic receptors which directly increases membrane permeability of ions

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11
Q

Ionotropic receptors are…

A

ligand-gated ion channels

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12
Q

Describe the slow chemical synaptic transmission

A

binding to metabotropic receptors which results in activation of a signaling cascade and usually results in the opening of an ion channel

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13
Q

Metabotropic receptors are…

A

G-protein coupled receptors

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14
Q

In a chemical synapse, an action potential first triggers __ in the presynaptic neuron membrane.

A

Ca influx

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15
Q

Synaptic potentials can be __ or __

A

excitatory; inhibitory

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16
Q

What is a synaptic potential?

A

graded change in the postsynaptic cell in response to neurotransmitter binding, lasting 10-20 ms

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17
Q

What is an EPSP?

A

A synaptic potential that depolarizes the membrane (excitatory) increasing the probability of an action potential

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18
Q

What is an IPSP?

A

a synaptic potential that hyperpolarizes the membrane (inhibitory), decreasing the likelihood of an action potential

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19
Q

If the post-synaptic channels that are opened allow cations to enter the cell or anions to exit, the post-synaptic membrane will become __

A

depolarized

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20
Q

What are the two most common neurotransmitters that elicit EPSPs (excitatory neurotransmitters)

A

Acetylcholine (Ach) and glutamate

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21
Q

T/F: The local change in the membrane is termed an EPSP, and this IS an action potential

A

FALSE: this is not an action potential, it just increases the likelihood one will happen

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22
Q

What conditions would cause the post-synaptic membrane to become hyperpolarized?

A

if the post-synaptic channels that are opened allow anions to enter the cell or cations to leave

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23
Q

The local change in the membrane potential when a hyperpolarization occurs is termed a?

A

IPSP - inhibitory post-synaptic potential

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24
Q

What are the two common inhibitory neurotransmitters (ones that elict an IPSP)

A

gamma-aminobutryic acid (GABA) and glycine

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25
Q

Multiple EPSPs can trigger an __ __

A

action potential

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26
Q

T/F: A single EPSP is sufficient enough to bring the axon hillock to threshold

A

false, more than one EPSP is required to initiate a post-synaptic action potential

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27
Q

Define spatial summation:

A

if a number of EPSPs occur simultaneously, at different locations of the dendritic arbor of a neuron, their summed EPSPs (net change in potential at the hillock) may bring the axon hillock membrane to threshold

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28
Q

Define temporal summation

A

stimulation may also occur if multiple EPSPs occur within a short duration (before the previous EPSP has dissipated, roughly 50 ms)

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29
Q

The excitatory/ inhibitory neurons __ to the axon hillock are the most powerful

A

closest

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30
Q

Multiple receptors, with __ functions, may bind a __ type of neurotransmitter

A

different; single

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31
Q

ACh is excitatory in __ muscle ( __ receptors) and inhibitory in __ muscle (__ receptors)

A

skeletal - nicotinic
cardiac- muscarinic

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32
Q

Which neurotransmitter binds to both nicotinic and muscarinic receptors?

A

acetylcholine

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33
Q

Ach slows the heart rate by ___

A

hyperpolarizing

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34
Q

For most skeletal muscles, each fiber is only innervated by __ neuron

A

one

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35
Q

Acetylcholine is the __ neurotransmitter at the __ junction

A

excitatory; neuromuscular

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36
Q

The nicotinic Ach receptor is a single __ gated channel for both __ and __

A

ligand
Na and K

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37
Q

Discuss how Ach directly generates a muscle contraction

A

opens ligand-gated channels for Na and K which depolarizes the muscle Vm, generating an AP and causing muscle contraction

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38
Q

What are the two types of neurotransmitters?

A

1 small molecule neurotransmitters and amino acids
2 neuroactive peptides

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39
Q

Small molecules neurotransmitters and amino acids are synthesized and released at the __ __

A

axon terminal

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40
Q

Neuroactive peptides are synthesized at the __ __ and transported to the __ __

A

cell body; axon terminal

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41
Q

T/F: A neuron may release more than one neurotransmitter

A

true - but it releases a characterisitic one

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42
Q

A neuron can respond to __ __ of neurotransmitters, not just __

A

many types; one

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43
Q

Define synaptic plasticity

A

ability to change synaptic strength overtime, believed to be an important mechanism in learning

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44
Q

What are two basic examples of synaptic plasticity in a sea slug?

A

Habituation and sensitization

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45
Q

Define habituation

A

decrease in intensity of a reflex response to a repeated stimulus (mechanism of synaptic plasticity)

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46
Q

Define sensitization

A

the prolonged enhancement of a reflex response to a stimulus, which results from a second stimulus that is novel of noxious (mechanism of synaptic plasticity)

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47
Q

Describe habituation and sensitization in Aplysia (sea slug)

A

h: Aplysia will initially withdraw its gills when something comes in contact with the siphon or mantle shelf, but after contact proceeds repeatedly, a. will decrease this withdrawal behavior

s: then, if it receives a shock to the head, the slug will once again retract its gils in response to stimulation by the siphon

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48
Q

Synaptic responses mirror the __ __ of the slug

A

behavior responses

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49
Q

The synapse between __ neuron and __ neuron is a key site

A

sensory and motor

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50
Q

Repeated stimulation of __ neuron leads to decrease in ___ ___, the mechanism of __

A

sensory
Ca influx
habituation

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51
Q

Shock to the tail or head causes ___; __ release, causing a prolonged __ and activated increase of __ __ and increased release of __

A

sensitization
serotonin
AP
Ca influx
neurotransmitter

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52
Q

EPSP magnitude increases over __ when neurons are __ stimulated via tetanus, this increase is ___

A

baseline; repeatedly
LTP (long term potentiation)

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53
Q

NMDA receptor only opens when both __ and __ synaptic neurons are firing after __ stimulation

A

pre + post
tetanic

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54
Q

All sensory stimuli are ultimately __ to action potentials, and sent to the CNS by __ __

A

transduced
labelled lines

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55
Q

How do labeled lines send sensory stimuli to the correct place?

A

the wires are kept straight by ordering specific sensory axons to different specific regions of the brain

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56
Q

Define sensory receptor cells

A

specialized cells which react to certain stimuli and in turn stimulate an afferent neuron

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57
Q

Receptor potential amplitude varies with _ __

A

stimulus strength

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58
Q

AP frequency varies with __ __ __

A

receptor potential amplitude

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59
Q

Describe the function of an afferent neuron

A

integrates the amplitude of the stimulus from receptor cells and either fails to generate and AP, generates and AP, or generates multiple APs

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60
Q

Movement of the steriocillia (hairs) to the right __ the membrane while movement to the left __ the membrane

A

depolarizes
hyperpolarizes

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61
Q

Where are sensory cells located for hearing?

A

semicircular canals of the inner ear

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62
Q

_ __ in the canals moves hair cells and causes depolarization/hyperpolarization dependent on the __ and gives CNS information on __

A

Fluid movement
direction
acceleration

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63
Q

What do hair cells transduce?

A

vibration/ acceleration

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64
Q

Describe the path of sound wave travel

A

waves travel through the auditory canal, across the tympanic membrane, and to the bonds of the middle ear to resonate the oval window. The resulting waves in the cochlear media fluid displace hairs at specific locations n the basilar membrane dependent on frequency

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65
Q

__ frequencies are found closest to the oval window and __ frequencies are found at the center of the cochlea

A

higher; lower

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66
Q

In vertebrate taster buds, the receptor cells are not __ but __ __

A

neurons
epithelial cells

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67
Q

Tastes are encoded by different __

A

receptors

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68
Q

Describe the way salt is tasted

A

increase in sodium ions in the mouth can depolarize salt receptors

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69
Q

Sour taste is likely mediated by _- __ deactivation of __ __ __ channels. With __ permeability vastly decreased, __ begins to dominate the resting membrane potential, resulting in a __

A

H+ ion
ionotropic K+ leak
K+
Na+
depolarization

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70
Q

Sweet, umami, and bitter tastes are all __; they have different __ but similar __ __ __

A

metabotropic
receptors
downstream second messengers

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71
Q

Olfactory GPCRs can depolarize the membrane though activation of __ dependent __ channels

A

Ca2+, Cl-

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72
Q

T/F: Rods are more numerous than cones

A

true

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73
Q

In humans, the fovea covers 0.01% of the visual field but has high density of __ cells

A

photoreceptor

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74
Q

Describe how light moves through the cells of the eye

A

rods and cones send information to bipolar cell to ganglion cell to the optic nerve. Sometimes an amacrine cell acts as an intermediate between a bipolar and ganglion cell

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75
Q

What are vertebrae photoreceptors?

A

rods and cones

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76
Q

Define rods

A

photoreceptors that are more sensitive and used for vision in dim light

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77
Q

Define cones

A

photoreceptors that are used in bright light to produce color vision

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78
Q

Discuss the composition of rods and cones

A

Rods: Rhodopsin = opsin protein + retinal
Cones: Photopsin = opsin protein + retinal

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79
Q

Retinal is derived from vitamin _ and is replenished in the __ __

A

A
pigment epithelium

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80
Q

In the cones, the opsin responds to different _-

A

wavelengths

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81
Q

In a dark current, more __ is released

A

glutamate

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82
Q

Under dark conditions: __-__ __ channels are always open, Thus, the permeability of __ in the dark rods is very high and the cell is in a constant state of __

A

cGMP-gated Na
Na
depolarization

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83
Q

Dark current is costly as ____ is needed to maintain a constant __

A

Na+/K+ ATPases
potential

84
Q

__ activation hyperpolarizes the membrane

A

rhodopsin

85
Q

1) light changes the __ of the __ receptor, located on the intracellular disk membranes 2) activating its __ __ 3) __, the __ messenger is then degraded 4) deactivating plasma membrane __ channels, __ the rod cell

A

conformation; rhodopsin
G protein
cGMP; secondary
Na; hyperpolarizing

86
Q

Dark current leads to a ?

A

graded response

87
Q

Under light conditions: __ is enzymatically degraded by a phophodiesterase, closing __ __ channels, minimizing the __ current and leads to __ , graded by the __ of the light stiumuls

A

cGMP
cGMP-gated Na+ channels
dark
hyperpolarization
intensity

88
Q

Glutamate is normally __ on postsynaptic _- cells (__-__)

A

inhibitory
bipolar
non-spiking

89
Q

With more light, there is less __ released on __ cells, which increases the __ __ release by the __ cells and leads to an __ in the __ cell (__)

A

glutamate; bipolar
excitatory neurotransmitter
bipolar
EPSP; ganglion; spiking

90
Q

Compare neural transmission with endocrine

A

neural: fast, addressed signals, neurotransmitters
endocrine: slow, broadcast signaling, hormones

91
Q

What are the three types of hormones?

A

steroid
peptide and protein
amine

92
Q

Steroid hormones are __ bound and include __ and __

A

carrier
LDL, HDL

93
Q

Describe steroid hormones

A

synthesized on demand, NOT stored
secreted by diffusion
receptors are mainly intracellular, but can be extracellular

94
Q

What are six steroid hormones?

A

aldosterone, cortisol, testosterone, estradiol, pregnenolone, and cholesterol

95
Q

What are two examples of peptide and protein hormones?

A

Gonadotropin-releasing hormone (GnRH)
insulin

96
Q

Describe peptide and protein hormones.

A

stored in vesicles and secreted on demand
receptors are extracellular, typically GPCRs

97
Q

Insulin is stored in?

A

vesicles

98
Q

Describe amine hormones

A

stored in vesicles and secreted on demand

99
Q

What are the two main classes of amine hormones?

A

hydrophilic catecholamines and lipophilic iodothyronines

100
Q

Describe hydrophilic catecholamines

A

use extracellular receptors

101
Q

Describe lipophilic iodothyronines

A

use intracellular receptors

102
Q

What are three examples of catecholamines

A

dopamine, norepinephrine, and epinephrine

103
Q

What are two examples of thyroid hormones?

A

Thyroxine (T3) and Triiodothyronine (T3)

104
Q

What are three examples of endocrine systems?

A

vertebrate pituitary gland, mammalian nutrient metabolism, and vertebrate salt and water balance

105
Q

What are hormones responsible for?

A

any and all metabolic changes in target cells, including up-regulation and down-regulation of enzymes, and transcription of DNA

106
Q

What kinds of receptors can hormones bind to?

A

G protein-coupled
intracellular, or enzyme-linked membrane receptors

107
Q

Steroid hormones act as __ __ once bound to an intracellular receptor molecule

A

transcription factors

108
Q

T/F: hormones cannot activate second-messenger systems via G proteins

A

False

109
Q

Hormones may have a __ __ effect, due to many cells having __ receptors

A

whole-organism
many
e.g. insulin

110
Q

Vasopressin (ADH) and oxytocin are produced in __ and released into the blood flow __

A

hypothalamus
anterior pituitary

111
Q

What two hormones does the posterior pituitary release?

A

antidiuretic hormone (ADH) aka vasopressin
Oxytocin

112
Q

Both __ and __ are peptide hormones that are synthesized in the hypothalamus and stored in the __ pituitary

A

ADH, oxytocin
posterior

113
Q

What is ADH responsible for?

A

water retention in the kidneys, vasoconstriction

114
Q

What is oxytocin responsible for?

A

contraction of the uterus during birth, lactation, love

115
Q

The anterior pituitary gland exhibits neurosecretory control of __ cells as it responds to neurohormones released by the __

A

endocrine; hypothalamus

116
Q

What is the hypothalamo-hypophysial portal system?

A

dedicated vascular pathway that connects the hypothalamus and anterior pituitary

117
Q

What two major groups of hormones act on are produced in the anterior pituitary gland?

A

non-endocrine and endocrine

118
Q

What do non-endocrine tissues influence?

A

growth and metabolism of bone and muscle

119
Q

Most hormones of the anterior pituitary are classified as __ hormones

A

tropic

120
Q

Define tropic hormones

A

those that stimulate release of other hormones

121
Q

What is an example of a hormone that impacts a non-endocrine tissue?

A

growth hormone

122
Q

What is an example of a hormone that impacts other endocrine glands?

A

ACTH

123
Q

What is the function of ACTH?

A

stimulates the production of cortisol (a stress hormone) from the adrenal cortex

124
Q

What are the two major types of neurohormones released in the hypothalamus?

A

releasing hormones, release inhibiting hormones

125
Q

Releasing hormones and releasing inhibiting hormones stimulate release of __ pituitary hormones

A

ANTERIOR

126
Q

RHs and RIHs enter the __ vessels, where they control secretory cells of the __

A

portal; adenohypophysis

127
Q

What are the seven hormones produced in the hypothalamus and released in the anterior pituitary glands?

A

TSH, ACTH, MSH, GH, LH, FSH, and prolactin

128
Q

T/F: the hormones released in the anterior pituitary gland are separated by a subpopulation of cells

A

true - each area of cells secrete a specific hormone

129
Q

The adrenal cortex is controlled by the __/__

A

hypothalamus/ pituitary

130
Q

What is the most common mechanism of hormonal modulation?

A

negative feedback

131
Q

Define negative feedback

A

a hormone inhibits its own secretion by acting on the axis it is part of

132
Q

Define synergism

A

one hormone amplifying the effects of another

133
Q

What is an example of synergism?

A

vasopressin increases the effects of CRH on the secretion of ACTH

134
Q

Define permissiveness

A

mechanism in which one hormone is required for the other to work

135
Q

What is an example of permissiveness?

A

cortisol permits epinephrine to cause vasoconstriction

136
Q

Define antagonism

A

one hormone opposing the action of another

137
Q

What are four examples of how hormonal modulation is accomplished?

A

negative feedback, synergism, permissiveness, and antagonism

138
Q

Insulin acts to __ blood glucose

A

decrease

139
Q

Glucagon and epinephrine are insulin __

A

antagonists

140
Q

Glucagon and __ are synergistic to each other

A

epinephrine

141
Q

What are the two main hormones in mammalian nutrient metabolism

A

insulin and glucagon

142
Q

Insulin is secreted by the beta cells of the __, and it __ blood glucose, causing cells to take __ glucose, fatty acids, and proteins. Opposes __, storage of __

A

pancreas
lowers
in
glucagon
nutrients

143
Q

Insulin is stimulated by high __ __ levels, high __ meal, GI hormones and __ activity (rest and digest)

A

blood glucose
protein
parasympathetic

144
Q

Insulin promotes the formation of __, __, and __

A

glycogen, triglycerides, proteins

145
Q

Glucagon is secreted by the __ cells of the pancreas, and __ blood glucose levels, opposing action of __. Mobilization of ___

A

alpha, raises, insulin
nutrients

146
Q

High carbohydrate meal triggers insulin __ and glucagon __

A

increase; decrease

147
Q

Vasopressin causes __ to be incorporated into the __ membrane of duct epithelial cells for __ retention

A

aquaporins; apical; water

148
Q

What are the three fluid compartments of the body?

A

intracellular body fluid
interstitial fluid
blood plasma

149
Q

What system is involved in vertebrate salt and water balance?

A

Renin-angiotensin-aldosterione system

150
Q

Renin-angiotensin-aldosterone system conserves water along with __

A

ADH

151
Q

Low blood pressure stimulates __ secretion by the kidney; which catalyzes the production of __, which triggers __ secretion by the adrenal cortex

A

renin
angiotensin
aldosterone

152
Q

__ increases absorption of Na+ in the kidney, water follows by __

A

Aldosterone
osmosis

153
Q

Angiotensinogen secretes __ and produces __. Angiotensin I produces __, which has four functions

A

renin; angiotensin I
angiotensin II

154
Q

What is the function of angiotensin II?

A

aldosterone secretion, stimulates vasopressin secretion, promotes thirst, and stimulates constriction of systemic arterioles

155
Q

Angiotensiogen stimulates hormones which adjusts __ __ pressure

A

arterial blood

156
Q

__ __ __ acts to excrete water from the body

A

atrial natriuretic peptide (ANP)

157
Q

Stretch receptors in specialized muscle cells in the atrium of heart sense __ blood pressure and secrete __

A

high
ANP

158
Q

ANP inhibits _- reabsorption by kidneys, acting as a diuretic

A

Na

159
Q

What is a diuretic

A

someting that promotes the production of dilute urine

160
Q

AND opposes the actions of the __ and __ systems

A

ADH, RAA

161
Q

Muscle is a tissue built of specialized __ cells also called?

A

contractile
muscle cells; muscle fibers; myocytes; myofibers

162
Q

What are the two main categories of muscle?

A

striated muscle tissue and smooth muscle tissue

163
Q

Describe striated muscle tissue

A

appearance of alternating light and dark bands, which are collections of contractile proteins (sarcomeres). Makes up the skeletal muscle (most) and cardiac muscle

164
Q

Describe smooth muscle tissue

A

uses contractile proteins that are not organized into sarcomeres, so there’s no striated appearance. Smooth muscle lines the blood vessels, gut, respiratory tract

165
Q

Skeletal muscle hierarchy: __ muscle consists of multiple bundles of muscle __. __ are long, multinucleate, cylindrical cells, organized in parallel. Each myofiber consists of many parallel __. Each myofibril is composed of repeated __.

A

skeletal
fibers; myofibers
myofibrils
sarcomeres

166
Q

What is the fundamental unit of contraction?

A

sarcomere

167
Q

What is the composition of sarcomere?

A

actin and myosin filaments

168
Q

Skeletal muscle fibers are subdivded into repeated long __ sarcomeres with a _ __ at each end

A

sarcomeres
z-disk

169
Q

Actin is the __ filament, while myosin is __

A

thin; thick

170
Q

Where is actin found?

A

attached at the midpoint to z-disks and project to either side

171
Q

Where is myosin found?

A

at the center of each sarcomere and attach to actin at each end

172
Q

Titin filaments make up __ of total muscle mass. and they function as __ __, allowing the muscle to __

A

10%
elastic bands
relax

173
Q

Each actin filament is composed of: 1) two twisted, bended polymer chains of globular __ molecules with a _ binding domain 2) two strands of __ molecules that lie from end to end in the grooves formed by the actin chains. 3) __ molecules attached at intervals to tropomyosin strands

A

actin; myosin
tropomyosin
troponin

174
Q

__ and __ act to control whether myosin __ can interact with __ filaments

A

tropomyosin; troponin
cross-bridges
actin (thin)

175
Q

Each myosin molecule has a globular head with an __ binding domain, a __ pocket, and a flexible __ with two light chains of __

A

actin
nucleotide
neck
myosin

176
Q

What is the sliding filament theory?

A

muscle inches and releases then inches and releases until fully contracted
uses ATP

177
Q

In the absence of __, tropomyosin __ the myosin binding sites on the __ filaments

A

Ca2+, blocks, actin

178
Q

Fast chemical transmission at the NMJ
AP __ terminal
1) __ channels open
2) __ is released into the __
3) __ binds to __ receptors
4) _- receptors __ the muscle cell
5) The muscular __ propagates to all parts of the muscle, stimulating __

A

depolarizes
1 Ca
2 ACH; synapse
3 ACh; nicotinic
4 nicotinic; depolarize
5 AP; contraction

179
Q

The __ ( the myocyte cell membrane) forms deep transvers invaginations into the myocyte called __ __

A

sarcolemma
transverse (T) tubules

180
Q

T/F: The T-tubule system is discontinous with the ECF

A

false

181
Q

What is the sarcoplasmic reticulum?

A

network of longitudinal membrane-bound tubules contained entirely within the myocyte, between two T-tubules

182
Q

What joins the T-tubules and the SR?

A

protein receptor channels

183
Q

At the T-tubule-SR junction, the SR contains a __ channel/receptor called a __ __. The t-tubule contains another receptor (not a channel) called __ __

A

ryanodine receptor (RyR)
dihydropyridine receptor (DHPR)

184
Q

In skeletal muscle, __ and __ form a complex at the T-tubule-SR-junction. __ is activated by T-tubule depolarization, which stimulates __ to release __ from the __ into the __

A

RyR; DHPR
DHPR
RyR; Ca
SR; cytoplasm

185
Q

Excitation-Contration coupling: sarcolemma depolarization
1 _ release at the __
2 Opening of __ gated __ channels
3 __ propagates down the ____

A

1 ACh; NMJ
2 ACh; ion
3 AP; T-tubules

186
Q

Excitation-Contration coupling: Ca efflux from the SR
4 __ reaches the __ receptors, opening the associated __ receptors, and releasing __ from the __
5 __ ions diffuse into the __ and bind to __, enabling __ __
6 Cross bridges go through several cycles of __ while __ is present

A

4 depolarization; DHPR: RyR;Ca; SR
5 Ca; cytosol; troponin; filament sliding
6 movement; Ca

187
Q

Excitation-Contration coupling: AP termination
7 Meanwhile at the __, __ hydrolizes __ to terminate the __
8 __ ceases at the __ and __ channels close
9 __ actively transport __ back into the __

A

NMJ; AChE; ACh; AP
Depolarization; T-tubules; RyR
Ca ATPases; Ca; SR

188
Q

What are the three main steps of Excitation-Contration coupling?

A

Sarcolemma depolarization
Ca efflux from the SR
AP termination

189
Q

Smooth muscle lacks __ and __ but has 5x the amount of __ filaments than striated muscle

A

sarcomeres; troponin; actin

190
Q

Discuss the organization of actin and myosin filaments in smooth muscle

A

organized into diagonal bundles around the periphery of the cell; when smooth muscle contracts, the peripheral filaments slide along each other, and the myocytes turn from spindle shaped to globular

191
Q

T/F: The ATPase activity of smooth muscle is faster than that of SO fibers

A

FALSE: Slower

192
Q

Smooth muscle sometimes has __ __ that function as a single unit of __ muscle

A

gap junction
smooth

193
Q

How does contraction of smooth muscle occur?

A

slight depolarization - opens plasma membrane voltage gated Ca channels

194
Q

Ca activates smooth muscle predominately by regulating __ state of __ proteins. Relaxation is accomplished by pumping the __ back out of the cell

A

phosphorylation; myosin
Ca

195
Q

Smooth muscle cells are innervated by the __, which occurs by diffuse __ release (__ or __)

A

ANS
neurotransmitter
ACh, catecholamines

196
Q

T/F: Ca enters SMC in a variety of ways

A

True

197
Q

Smooth muscle: __ binds with __, complex activates the __ __ __ __ (MLCK), which activates __ __ and allows __

A

Ca; calmodulin
myosin light chain kinase
myosin ATPase
contraction

198
Q

Describe cardiac muscle

A

uninucleate branched cells that form intercalated discs, which contain gap junctions (electrical synapses) and desmosomes. Specialized pacemaker cells generate endogenous action potentials

199
Q

Action potentials of cardiac muscle are __ lasting, due to __ ion flux across the cell membrane that __ __. this ensures a __ contraction of the muscle cell and coordinated pumping by the heart

A

long; Ca
prolongs depolarization
prolonged

200
Q

Cardiac cells have limited __ capacity and function mainly __

A

glycolytic; oxidatively

201
Q

Describe how muscles work in pairs

A

function in antagonistic pairs, because muscles can only forcibly shorten, they cannot forcibly lengthen

202
Q

Muscle force is directly proportional to __ __ area of __ in a muscle, or __ acting in __

A

cross-section
sarcomeres
sarcomeres; parallel

203
Q

What are the four different types of muscle contractions?

A

isometric
isotonic (eccentric or concentric)

204
Q

What is an isometric contraction?

A

cross-bridges are active, but there is not enough force to generate movement

205
Q

What is an isotonic contraction

A

cross-bridges are active, there is enough force to generate movement

206
Q

What’s the difference between a concentric and eccentric isotonic contraction?

A

concentric - picks up
eccentric - puts down

Physiology (4 decks)

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