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107 terms

Muscle and Neural Tissue

Chapters 10 and 12
STUDY
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produce skeletal movement, maintain posture and body position, support soft tissues, guard entrances and exits, maintain body temperature, and store nutrient reserves
list the functions of the skeletal muscles
epimysium
the dense layer of collagen fibers that surround an entire skeletal muscle
whole muscle, fasicle, muscle fiber/cell, myofibril, myofilaments
list in order the layers of a muscle tissue starting witht the whole muscle
long, develop through fusion of myoblasts, contain hundreds of nuclei
list the distinctive features of skeletal muscle fibers
endomysium
surround individual muscle cells, contain capillaries and nerve fibers contracting muscle cells, contains satellite cells that repair damage
perimysium
surrounds muscle fiber bundles (fasicles), contains blood vessel and nerve supply to fasicles
CNS
skeletal muscles are controlled by nerves of the _________
sarcolemma
considered the cell membrane of the a muscle cell, surrounds the sarcoplasm of muscle fiber, a change in transmembrane potential begins contractions
T tubules
transmit action potential through cell, allow entire muscle fiber to contract simultaneously
myofibrils
lengthwise subdivisions with muscle fibers, made up of bundles of protein filaments (myofilaments) which are responsible for muscle contraction
thin filaments
made up of protein actin
thick filaments
made up of protein myosin
sarcoplasmic reticulum
a membranous structure surrpounds each MYOFIBRIL, helps transmit action potential to myofibril, forms terminal cisternae which are attached to t tubules
a triad
formed by a t tubule and 2 terminal cisternae; release calcium ions into sarcomeres to begin muscle contraction
sarcomeres
contractile units of muscle, structural units of myofibrils
titin
strands of protein that reach from tips of thick filaments to the z line, also help in stablizing the filaments
muscle contraction
___________ is caused by the interactions of thick and thin filaments
nebulin
holds f actin strands together
tropomyosin
double stranded and prevents actin-myosin interaction
myosin
active sites on gactin strands bind to _______
troponin
globular protein that binds tropomyosin to g actin and controlled by calcium ions
calcium and troponin complex forms, tropomyosin moves away from sites of actin, site exposed, actomyosin bridge forms
troponin and tropomyosin initiates contraction how?
thick filaments
contain twistin myosin subunits and titin strands that recoil after stretching
mysoin tail
part of myosin molecule that binds to other myosin molecules
myosin head
part of myosin molecule that is made up of 2 globular protein subunits; interacts with the nearest thin filament
myosin heads interact with actin filaments during contraction
how are cross-bridges formed?
sarcolemma
cell membrane of skeletal muscle
sarcoplasm
cytoplasm of skeletal muscle fiber
myofilaments
consist of bundles of protein fibers
a bands
consist of thick and thin filaments, are in the center of sarcomeres, account for dark colorations in the banded appearence of myofibrils
tropomyosin molecules
at rest, active sites on the actin are blocked by___________molecules
troponin molecules
at rest, the tropomyosin molecule is held in place by __________molecules
sarcolemma
neural stimulation of _______ caused excitation-contraction coupling
cisternae of sarcoplasmic reticulum
__________ release _______ which triggers interactions of thick and thin filaments consuming ATP and producing tension
synaptic terminal
contains vesicles filled with acetylcholine
synaptic cleft
space between neuron and muscle
motor end plate
location for acetylecholine receptors
acetlecholine, sodium
the transmembrane potential of the motor end plate changes when the binding of ________ to receptors on the motor end plate increases the permeability of the cell membrane to ______.
rigor mortis
fixed muscular contraction after death caused by ion pumps ceasing to function causing calcium ions to build up in sarcoplasm
ATP into ADP and P
myosin reactivation after contraction occurs when the free myosin head splits ____ into ____ and ____. the energy released is used to recock the myosin head
twitch
single stimulus-contraction-relaxation sequence in a muscle fiber is described as?
treppe
increase in peak tenion after relaxation phase is described as?
wave summation
increas in tension or summation of twitches
incomplete tetanus
a muscle producing peak tension during rapid cycles of contraction and relaxation is said to be?
motor unit
all the fibers controlled by a single motor neuron is defined as?
recruitment
smooth, but steady increase in muscular tension produced by an increase in number of motor units is defined as?
isotonic
tension rises and skeletal muscles length changes to overcome resistance is what kind of contraction? ex: lifting an object, running, walking
aerobic metabolism
a resting muscle generates most of its ATP by?
creatine phosphate
what acts as an energy reserve in muscle tissue?
ATP, pyruvic acid, and lactic acid if pyruvic acid accumulates
during anaeorbic glycolysis what is produced?
lactic acid removal and recycling; oxygen debt; heat production and loss
what are the three steps involved in the recovery period? LOH
growth hormone, testosterone, thyroid hormone, epinephrine
list all the hormones that help in muscle contraction (GTTE)
type I fibers (slow fibers)
the type of muscle with low fatigue resistance
fast fibers
white muscles
slow fibers
red muscles
integumentary system
heat energy produced from muscle contraction is released through _______ system
smooth muscle
contains neurons that are under involuntary control, uninucleate, and contain thin filaments that are attached to dense bodies
placisity
the ability of smooth muscle to function over a wide range of lengths
anaerobic endurance
length of time muscular contraction can continue to be supported by glycolysis and by the existing energy reserves of ATP and C
voltage-gated sodium
The depolarization phase of an action potential results from the opening of _______ channels
axon hillock
Where in the neuron is an action potential initially generated?
the opening of voltage gated potassium channels
The repolarization phase of an action potential results from __________.
slow closing of potassium channels
Hyperpolarization results from __________.
ACh
Cholinergic synapses release the neurotransmitter
hyperpolarizations
IPSPs (inhibitory postsynaptic potentials) are local
spatial summation
Summation that results from the cumulative effect of multiple synapses at multiple places on the neuron is designated
CNS
cranial and spinal nerves comprise the _________
afferent divisions
brings sensory info from PNS to CNS
receptors
sensors that detect changes in the environment
efferent divisions
brings sensory info from CNS to PNS
somatic nervous system
controls skeletal muscle contractions
ANS
provides automatic regulation of smooth and cardiac muscles
sympathetic
accelerates heart rate
parasympathetic
slows heart rate
somatic nervous system
controls skeletal muscle contractions (voluntary)
passive
membrane channels that are always open are called __________
active and passive
at normal resting potential (-70mV) _____ and _____ processes are in balance
graded potential
change in resting potential that decreases with distance
active potential
an electrical impulse that is propagated along the surface of an axon and does not diminish as it moves away from its source
1,3,2,4,
steps involved in the generation of action potential: (place in order)
1) depolarization to threshold
2) potassium channel activation-t.m. potent. reached, Na channels close/inactivate, K channels open and K moves out causing repolarization
3) sodium channel activation-large influx of sodium ions causing depolarization, action potential rises
4) return to normal permeability-once membrane reaches threshold levels (-70mv) sodium channels are ready to be opened and potassium channels are ready to be closed, K ions swim out of cell quickly causing hyperpolarization, K channels finally close and action potential is over
hyperpolarization
inside of cell loses most of its positive ions
absolute refractory period
Na channels open or inactivate and no action potential is possible
relative refractory period
membrane potential almost normal and stimulus initiates action potential
diameter
axon _______ effects action potential speed
type a fibers
large in diameter, myelinated, high speed, carry rapid info from/to CNS
type b fibers
medium diameter, myelinated, intermediate speed (18m/sec), carry intermediate signals
type c fibers
small in diameter, unmyelinated, slower speed (1m/sec), carry slower info
saltatory conduction
the process that conducts along an axon at a high speed rate is called ____________conduction
electrical synapse
pre and post synaptic cells bound by interlocking membrane proteins (occur in some areas of the brain and eye)
chemical synapse
excitatory neurotransmitters that cause depolarization and promote action potential generation
gap junctions
at an electrical synapse, the presynaptic and postsynaptic membranes are locked together at __________
depolarize, hyperpolarize
excitatory neurotransmitters can _________ and promote the generation of action potential and neuroinhibitory neurotransmitters cause _________ and suppress the generation of action potentials
ACh
what type of neurotransmitter is found in cholinergic response?
centriole
neurons lack _________, therefore, do not divide once formed.
calcium
extracellular _________ is required for triggering ACh exocytosis
sodium
_________ions are required for the cause of depolarization
AChE
surplus acetylecholine is removed by an enzyme called _______.
GABA
produced presynaptic inhibition and appears to reduce anxiety
serotonin
effects emotial states
dopamine
inhibitory or excitatory effects (controls movements)
norepinephrine
has an excitatory/depolarizing effect on the post synaptic membrane
endophine
endogenous morphine is called ________.
IPSP
transient hyperpolarization of the postsynaptic membrane
neuromodulators
compounds that alter the rate of neurotransmitter release by the presynaptic neuron or change the postsynaptic cell's response to neurotransmitters.
temporal summation
addition of stimuli occurring in rapid succession at a single synapse that is actively repeated.
spatial summation
occurs when simultaneous stimuli applied at different location have a cumulative effect on the transmembrane potential (involves multiple synapses that are active simultaneously)
facilitated
a neuron whose transmembrane potential shifts closer to threshold is said to be _________.