Exam 5 Flashcards
(120 cards)
1
Q
functions of muscle tissue
A
movement
heat production
posture maintenance
2
Q
skeletal muscle characteristics
A
attached to bones and skin
movement and support of the skeleton
voluntary
tubular, striated, multinuclear
3
Q
cardiac muscle characteristics
A
walls of the heart
pump blood
involuntary
striated, single nuclear, branched, intercalated discs
4
Q
smooth muscle characteristics
A
forms muscle portion of hollow organs
move materials through organs, act as a sphincter
involuntary
fusiform, single nuclei
5
Q
principle properties of all muscles
A
excitability
contractility
extensibility
elasticity
6
Q
excitability
A
ability to receive and respond to stimuli
7
Q
contractility
A
ability to forcefully shorten
8
Q
extensibility
A
ability to stretch or extend
9
Q
elasticity
A
ability to recoil to resting length
10
Q
muscle as an organ
A
muscle tissue, blood vessels, blood-nerve
served by 1 nerve, artery, and 1+ veins
branches
11
Q
the connective sheath of a muscle
A
continuous with another and tendons joining muscles to bones
help transmit pulling force when contracts
provide entry/exit for blood vessel and nerves
12
Q
fascicle
A
bundle of muscle cells
13
Q
muscle fiber
A
muscle cells
14
Q
myofibril
A
muscles cell organelles composed of sarcomeres
15
Q
epimysium
A
a layer of CT under the deep fascia covers the muscle
16
Q
perimysium
A
a layer of CT around each fascicle
17
Q
endomysium
A
wraps muscle fiber individually
18
Q
myofibers
A
long and cylindrical
cells lie parallel
19
Q
sarcolemma
A
muscle cell membrane and polysaccharide
20
Q
nuclei of muscle
A
multinucleate
cells actually syncytium
need extra because cells are very metabolically active
21
Q
sarcoplasm
A
muscle cell cytoplasm
made up of myofibrils
parallel rods running length of the cell
responsible for contractility
22
Q
mitochondria in muscle
A
lots for ATP synthesis
23
Q
glycosomes
A
granules for stored glycogen
24
Q
myoglobin
A
red pigment for oxygen storage
25
sarcoplasmic reticulum
an elaborate form of ER
| series of interconnected tubules around myofibrils
26
transverse tubule (t-tubulues)
hollow elongated tube continuous with sarcolemma projects into the muscle cell
runs perpendicular to myofibrils
contain ECF
help spread action potential deep inside the cell
27
label structure of the sarcomere
see image
28
actin
thin filament
29
g-actin
individual amino acid
30
f-actin
strands of g-actin
31
troponin
regulatory protein
| three polypeptides bind to actin, tropomyosin, or Ca+2
32
tropomyosin
regulatory protein
chain of amino acid that spiral around actin
help stiffen actin backbone
inhibit binding of actin to myosin at rest
33
myosin
thick filament
protein with tail and 2 globular head
cross-bridge when myosin heads bind to actin
has ATP binding site
34
z lines
protein sheaths that attach to actin
| defines sarcomeres boundaries
35
i-band
thin, less dense, lighter band
| actin only
36
a-band
dense, dark bond
| actin and myosin
37
h-zone
center of a-band
| myosin only
38
m-line
dark like in the center of h-zone
| protein strands that attach adjacent myosin myofilaments
39
titin
elastic filament that extends from z-line to myosin
| holds myosin in place
40
sliding filament model
thick and thin filaments slide past one another
cross-bridge form when myosin heads attach to active sites on actin, cross-bridge attach and detach multiple times
pull actin toward the center of sarcomere past thick filament
shortening of sarcomere and generation of tension
resting: higher Ca+2 outside the cell
myosin heads in the cocked (high energy) position
tropomyosin blocks myosin-binding sites on actin, no cross-bridges form
muscle relaxed
41
neuromuscular junction
see image
skeletal muscles innervated by somatic motor neurons (GSE)
lower motor neuron exits spinal cord via ventral root and sends action potential to axon terminal where Ach stimulates muscle fiber at the junction
each muscle fiber only has 1 junction
AP travels toward the axon terminal
voltage-gated Ca+2 channels open
Ca+2 enters the cell and cause synaptic vessels to move and fuse with the membrane
Ach released into the synapse
Ach binds to ion channels on sarcolemma that allow Na and K movement
-Na influx and K efflux
-more Na moves than K causing local depolarization
-excites voltage-gated Na channels
Na enters the cell along a gradient, fires off AP
repolarization via Na channels close and K channels open
enzyme acetylcholinesterase in sarcolemma destroys Ach to stop signal
42
excitation-contraction coupling
the process by which AP leads to sliding of myofilaments
AP propagates along sarcolemma to t-tubule
tubule protein change shape and cause SR to release Ca+2 from terminal cisternae into the sarcoplasm
Ca+2 binds to troponin and changes shape, removing
tropomyosin block
myosin heads attach to actin-binding sites, cross-bridge cycle begins
43
cross-bridge cycle
myosin heads attach to actin, forms cross-bridge
ADP and Pi attached to myosin
Powerstroke: ADP and Pi release initiating Powerstroke
-myosin head swivels, pulling actin toward the center
cross-bridge detachment: binding site for ATP exposed
-ATP binds to myosin heads and breaks cross-bridge
cocking of myosin head:
-ATP is hydrolyzed
-energy stored in the myosin head
-myosin heads re-cocks to high energy position
the cycle continues as long as Ca+2 and ATP are present
44
motor unit
single motor neurons and all of the muscle fibers that innervate
45
single muscle twitch
single rapid contraction of a muscle in response to a threshold or above stimulus
see diagram
46
latent phase
no measure response (2msec) but all excitation-contraction coupling
AP generation
47
contraction phase
onset to the peak of shortening (10-100msec)
48
relaxation phase
contractile force no longer generated (10-100msec)
49
summation of contraction
accumulation of effects, one contraction build on the previous one
due to leftover Ca+2 in the sarcoplasm
if the frequency of contraction increases until fiber remains contracted without relaxation
50
tetanus
smooth sustain muscle contraction
AP refractory period still there, but does not rest
contraction until it runs out of Ca+2 or ATP
see diagram
51
recruitment
muscle made up of several motor units
the threshold for AP may vary
as signals get stronger, add more motor units
movements smooth because motor units contract out of phase
52
muscle tone
resting tension in skeletal muscle
no movement but muscles firm
relaxed muscles almost always slightly contracted
keep muscles firm, healthy, and ready to respond
53
length-tension relationship
the initial length of the sarcomere has a big effect on the amount of tension produced
sarcomere can generate most tension at resting length
optimal range 80-120% of normal resting length
see diagram
54
active internal tension
the force generated by thick and thin filaments (cross-bridge and Powerstroke)
55
passive external tension
elastic filaments, perimysium, endomysium, tendons
| depends on the degree of stretch
56
isotonic
same tension
tension increase to overcome resistance then length decrease but the tension does not change
used in all lifting exercises
57
concentric
muscle shortens to move a load
58
eccentric
muscle generates force as it lengthens
| leads to DOMs
59
isometric
```
same measure (length)
tension increase but never exceeds the resistance of the load, muscle length does not change
```
60
the force of muscle contraction depends on
what muscle is attached to (load)
recruitment (strength of stimulus)
frequency of stimuli-summation, tetany
degree of stretch
61
the main characteristic of ANS
maintaining homeostasis
input stimulus sensory receptor
integrate CNS
62
effector tissue of ANS
smooth muscle, cardiac muscle, glands
63
location of neurons in ANS
two neurons from CNS to cardiac/smooth muscle or gland
one cell body in the lateral horn of spinal cord other cell body in ganglia
Ach and norepinephrine
excitatory and inhibitory
the preganglionic neuron is myelinated and the postganglionic is not
64
location of neurons in somatic
lower motor neuron to CNS to skeletal muscles
cell body in the anterior horn of the spinal cord
only Ach
excitatory
myelinated axons
65
parasympathetic characteristics
rest and digest
responses localize to one organ
the response is brief, acetylcholinesterase breaks down Ach
responses essential to like by maintaining homeostasis
66
sympathetic characteristics
fight or flight
widespread, many organs affected
long-lasting
help cope with stress
67
locations of parasympathetic vs sympathetic
see image
68
affect on the head
S: dilate pupil, decrease secretions
P: constrict pupils, increase secretions
69
affects on lungs
S: dilate bronchioles
P: constrict bronchioles
70
affect on the heart
S: increase HR and force; vasodilate vessels
P: decrease and slows HR
71
affect on liver
S: increase glycogenolysis
P: increase glucose uptake from blood
72
affect on GI tract
S: relax smooth muscles, contract sphincters, decrease secretions
P: increase motility, dilate sphincters, increase secretions
73
affect on kidneys
S: vasoconstriction, decrease blood flow, decrease urine
P: increase urine
74
affect on bladder
S: relax smooth muscle, contract sphincter, inhibits peeing
P: contract bladder, relax the sphincter, promotes peeing
75
affects on sex organs
S: ejaculation of seminal fluid, contract pregnant uterus, and vagina
P: erection and increase vaginal lubrication, dilate
76
affect on blood vessels
S: vasodilation in skeletal muscle, liver, heart, adipose; vasoconstriction elsewhere
P: vasoconstriction?
77
affect on sweat glands
S: increase sweating
P: decrease sweating
78
affect on arrector pili muscles
S: contraction
P: dilation
79
affect on adipose tissue
S: increase lipolysis
P: decrease or no effect
80
what cranial nerves are involved in parasympathetic control
CN III, VII, IX, X
81
location of CNS exit
P: brainstem, CN III, VII, IX, X; sacral spinal cord via lateral horn and ventral root
S: thoracic and lumbar spinal cord via lateral horn and ventral root
82
location of ganglia
P: visceral effector organs
S: sympathetic chain near the spinal cord
83
length of neurons
P: pre-long and post-short
S: pre-short and post-long
84
neurotransmitters secreted
P: pre-and post- Ach
S: pre-Ach and post-Ach or norepinephrine
85
adrenal medulla route
sympathetic pathway
sympathetic fiber passes thru chain ganglia and peripheral ganglia to synapse directly on the adrenal medulla
release epinephrine and norepinephrine
results in an adrenaline rush
86
cholinergic receptors
receptors for Ach
| Ach released by preganglionic neurons so on all postganglionic neurons and effector tissue
87
nicotinic receptors
stimulated by nicotine
excitatory
found on postganglionic neuron (EPSP), hormone-producing cells - secrete NE/E, skeletal muscles- cause contraction
88
muscarinic receptors
stimulated by muscarine
excitatory and inhibitory depending on effector tissue
found on parasympathetic effector cells responding to Ach
89
adrenergic receptors
receptors for norepinephrine and epinephrine
activates 2nd messenger system
released by sympathetic postganglionic neurons
effects depend on the type of receptor-activated
effects last longer than Ach because no enzyme to degrade
90
alpha 1 receptor
most common
all sympathetic target organs except the heart
constrict blood vessel in the skin, abdominal viscera, kidneys, and salivary glands
constricts visceral organ sphincters, vas deferens, arrector pili muscles
91
alpha 2 receptors
inhibitory effects (decrease cAMP levels)
inhibits insulin secretion by the pancreas, increase glucagon secretion
promotes blood clotting
92
beta 1 receptors
increase HR and force
| stimulate kidneys to release renin to increase BP
93
beta 2 receptors
mostly inhibitory
relax the smooth muscle of lungs, digestive, urinary organs, and non-pregnant uterus
dilates blood vessels serving the heart, liver, and skeletal muscle
94
beta 2 receptors
stimulate lipolysis by adipose cells
95
beta-blockers
mostly beta 1, slows HR and BP
96
beta 2 agonists
asthma relief, relax smooth muscles
97
cocaine and amphetamines effects
increase release and block reuptake of norepinephrine
98
formation of ATP using creatine phosphate
```
regenerating ATP in muscles only
creatine + ATP = CP + ADP (at rest)
CP + ADP = creatine + ATP (when ATP is needed)
requires creatine kinase to catalyze rxn
10-15 seconds of exercise
increase CK levels means muscle damage
```
99
ATP formation using anaerobic respiration/glycolysis
breakdown of glucose to 2 molecules of pyruvic acid
some energy released and used to give 2 net ATP
no oxygen required
pyruvic acid goes into mitochondria with oxygen = ATP, if no oxygen pyruvic turns into lactic acid
lasts about 30-40 second of exercise
100
ATP formation using aerobic cellular respiration/oxidative phosphorylation
glucose + O2 = CO2 + H2O + 36 ATP
via Krebs cycle and ETC
requires oxygen and glucose
makes more and faster, O2 demand exceeds supply
101
muscle fatigue
occurs when muscle cannot contract regardless of stimulation
| cells run out of ATP, pH changes, and ion imbalance
102
oxygen debt
amount of extra oxygen that the body must take in to restore oxygen
103
slow oxidative
postural
endurance
neck, back, and legs
104
fast oxidative glycolytic
short term, intense, powerful movement
legs
reserves, replace CP, gets rid of lactic acid
105
fast glycolytic
sprinting, running, short-term fast
| legs and arms
106
color of skeletal muscle fibers
SO: red
FOG: red-pink
FG: white
107
fiber diameter of skeletal muscle fibers
SO: small
FOG: intermediate
FG; large
108
number of mitochondria in skeletal muscle fibers
SO: many
FOG: many
FG: few
109
number of capillaries in skeletal muscle fibers
SO: many
FOG: many
FG: few
110
twitch rate of skeletal muscle fibers
SO: slow
FOG: fast
FG: fast
111
myosin ATPase activity of skeletal muscle fibers
SO: slow
FOG: fast
FG: fast
112
ATP synthesis of skeletal muscle fibers
SO: aerobic
FOG: aerobic/glycolytic
FG: anaerobic
113
myoglobin content of skeletal muscle fibers
SO: high
FOG: high
FG: low
114
glycogen stores of skeletal muscle fibers
SO: low
FOG: intermediate
FG: high
115
rate of fatigue of skeletal muscle fibers
SO: slow
FOG: intermediate
FG: fast
116
aerobic exercise effects
increase metabolism, endurance, and resistance to fatigue
increase vascularity, # of mitochondria, myoglobin
enlarge slow-twitch convert FG to FOG
does not promote hypertrophy
swimming, jogging, fast-walking
117
anaerobic/resistance exercise
```
greater effect on fast-twitch fibers
increase strength and mass
increase # of myofibril, glycogen stores
convert FOG to FG
sprinting and weight lifting
```
118
synergists
group of muscles working together
119
antagonists
group of muscles working against each other
120
prime mover
muscle doing the majority of the work
