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Neurophysiology/muscle system
N/A
61
Anatomy
Undergraduate 4
10/25/2010

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Cards

Term
what is the charge on the inside of a cell vs. outside?
Definition
the charge on the inside is Positive (+) and the outside is Negative(-)
Term
what are the cations in high concentration inside of the cell?
Definition
Potassium K+
Term
what are the cations in high concentration on the outside of the cell?
Definition
Calcium (Ca++)
Term
what are the anions in high concentration inside the cells?
Definition
Proteins(-)
Term

what are the anions in high concentration outside the cells?

 

Definition
Chloride (Cl-) & Sodium (Na-)
Term
what is a sodium Potassium pump? what does it do?
Definition
active transport pump in Plasma membrane. it transports sodium ions out and Potassium ions in.
Term

what is the permeability of the membrane to Na+?

 

Definition
Realitively impermeable
Term
what is the permeability of the membrane to K+?
Definition
Membrane is readily permeable
Term
what are the 2 types of ion channels in the cell membrane?
Definition

ungated-open all the time

gated-open or close in response to stimulus.

Term
what are the types of gates and what is their position?
Definition
 Both gated and unclosed.
Term
what are the types of Na+ gates and what is their position during RMP?
Definition
Gated and Closed
Term

what is depolarization?

 

Definition

MP becomes more positive

 

*Na+ ions into cells

Term

what is hyperpolarization?

 

Definition

MP becomes more negative

 

*increase K+ or Cl- permeability

Term
what is repolarization?
Definition
Restores RMP
Term

what is an Action Potential?

 

Definition
sequence of rapid Depolarization & repolarization due to opening of voltage gated ion channels
Term
what happens during the Depolarization phase of AP?
Definition
Na+ Voltage gated ion channels open quickly & Na+ diffuses in --> Depolarization
Term

what happens during the repolarization Phase?

 

Definition

K+ voltage gated ion channels open more slowly.

-more permeable to K+ than at rest

-->K+ Diffuses out --> Repolarization

Term

what is an after potiental? and why does it occur?

 

Definition
K+ gates close slow so the increase in k+ permeability lasts longer than the time needed to return to rmp. --> Hyperpolarization.
Term

what role does a Na+/K+ pump play in Ap?

 

Definition
it actively transports (3) Na+ out and (2) K+ in
Term

what is the all or none response?

 

 

Definition
if it responds at all, it will respond completely.
Term

what are the 2 phases of the refractory period?

 

Definition

1. Absolute- absolutely insensitive to stimulus.

2. Relative-only a stronger than normal stimulus can depolarize.

Term
why does propagation of an ap occur?
Definition
because the neuron is stimulated at the dendrites, and AP is generated at axon hillock.
Term
how is the speed of propagation affected by the type of fiber?
Definition

Larger in Diameter- smaller

nerve-muscles

mylein- unmyleinated neurons

Term

what is a snyapse?

 

Definition
functional junction between 2 neurons
Term
2 types of synapses
Definition

1. Electrical- gap junctions conduct ions directly from cell to cell (uncommon)

2. Chemical- Most synapses

Term

Describe the structure of a chemical synapse.

 

Definition

Synaptic Cleft-tiny gap between pre and post cells.

Synaptic Knob/terminal-rounded end on the presynaptic axon.

Synaptic Vesicles-small sacs in synaptic knob which store neurotransmitters

Term
what are the events of synaptic transmission?
Definition

*AP arrives at axon.

*depolarization of terminal increases permeability of Ca+ in membrane

*Synaptic vesicles fuse to membrane

*release of neurotransmitters

*Neurotransmitters diffuse

*Neurotransmitters binds to specific receptor proteins

*Binding causes graded potentials by opening chemically gated channels.

*NTM is removed from cleft and allows  membrane to return to RMP.

Term
what 2 ways can summation of graded potentials occur
Definition

Spatial- many presynaptic fibers coverage on 1 pastsynaptic

 

Temporal- rapid successive stimuli

Term
what are the types of muscle?
Definition

Skeletal

Cardiac

Smooth

Term

which types of muscles are straiated?

 

Definition
Skeletal
Term
which muscles are involuntary?
Definition
Cardiac
Term

what are the functions of skeletal muscles?

 

Definition

Motion

Heat Production

Posture/Body Support

 

Term
what are the characterictics of a muscle
Definition

irritability/exciteability

contractability

extensibility

elasticity

Term
how are muscle fibers bound together to make a whole skeletal muscle.
Definition

each muscle fiber is bound by CT with others to form bundles.

Endomysium

Perimysium

Epimysium

Term
describe the layers of the CT
Definition

*Endomysium- CT covers/binds individual fibers.

*Perimysium-binds groups into fasciculi.

*Epimysium-covers entire muscle.

*Fascia-CT between seperate muscles

*Tendons-binds muscles to bone.

Term

Describe blood and nerve supply to skeletal muscle.

 

Definition

Blood- high metabolic activity requires extensive vascularity.

Nerves-skeletal muscle fibers can NOT contract unless stimulated by a nerve.

Term

what is a sarcomere?

 

Definition
the basic contractile/subunit of skeletal muscle
Term
describe the structure of a sarcomere.
Definition

IBands-only thin filaments(light Bands) include Z lines.

ABands-thicnk filaments-myosin(dark bands)

HZone-myosin only, where actin doesnt overlap in A band.

Zlines- dark lines in I band, forms edges of sarcomere.

MLines- within H bands Thickening of myosin filament.

 

Term
describe the structure of thick and thin filaments
Definition

Myosin(thick)

 *structure is like golf club.

 *globular head contain bonding  sites for ATP/ATOase & actin.

Actin(thin)

*Kidney bean shaped molecules to form helical strand.

*contain active sites for myosin binding.

Tropomyosin(thin)

*rod-shaped protein fills groove between strands.

*covers active site & prevents attatchment at rest.

Troponin(thin)

*attached at tropomyosin

*can attach to Ca++

 

 

Term
what is the sliding filament theroy?
Definition

when muscle contracts, decreases length.

fibers shorten by shortening myofibrils.

myofibrils shorten as a result from shortening sarcomere.

Term
what events take place when a sarcomere shortens?
Definition

*distance from Z-line shortens.

*H-band shortens(may disappear)

*I-Band shortens

*A-band does not shorten, appear close together.

Term
what types of ion channels are involved in producing local/graded potentials?
Definition
Chemical
Term

what is the role of Ca++ in muscle contraction?

 

Definition
It exposes active site by binding to troponin
Term
what 3 steps of muscle contraction require ATP?
Definition
Powerstroke, detatchment from actin, and active transport of Ca++
Term
what factors effect muscle contraction?
Definition

Thickness of each muscle fiber.

muscle architecture.

initial length of muscle at rest, to short or to long.

number of muscle fibers.

Term
what is isotonic contraction?
Definition
tension is constant while muscle changes length
Term
what is isometric contraction?
Definition
length of muscle is constant tension increases
Term
how does the all or none principal apply to the contraction of skeletal muscle fiber?
Definition
muscle fiber contracts completely or not at all.
Term
describe a muscle twitch
Definition
fiber contracts adn relaxes quiclky to a single stimulus.
Term
what is latent period?
Definition
time between stimulus and contraction.
Term
what is Tetanus?
Definition
smooth sustained contraction (no relaxation)
Term
What is Treppe?
Definition
increase in contraction strength after 1st twitch in a rested muscle.
Term
what is muscle tone?
Definition
even when a muscle appears relaxed continuous stimuli from the NS keeps muscle in sustained partial contraction.
Term
what is the series elastic component of a muscle?
Definition
CT that must be pulled tight before muscle will shorten.
Term
what energy sources does Skeletal Muscle rely upon at rest? 
Definition

Fatty Acids, Glycogen& glucose, Creatine Phosphate,

& Myoglobin.

Term
What is Muscle Fatigue?
Definition
the inability of a muscle to maintain its strength of contraction or tension.
Term
what is oxygen Debt?
Definition
the amount of oxygen required to metabolize lactic acid from anaerobic respiration.
Term
define the different types of skeletal muscle fibers.
Definition

1. Slow Twitch-(red) Long slow twitch, resist fatigue.

2.Fast Twitch(white) Short fast twitch, easily fatigued.

Term

how does smooth muscle differ structurally form skeletal?

 

Definition

smooth is smaller spindle shaped fibers. arranged in sheets. no straitions.

lacks well developed, sarcomeres, SR and t tubules.

Term
how does contraction of smooth differ from skeletal
Definition
smooth is slower and longer in duration than skeletal.
Term
what factors cause smooth muscle contraction?
Definition
Ca++ binds to Calmodulin, Ca++ ATP pumps are slower, requires less ATP.
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