- contractile units in myofibrils - defined as z-line to z-line

- assoc. w/ Ca2+ release - longitundinal or light SR - Ca2+ reuptake = Ca2+ binds to calsequestrin

Musch/ Wangemann Test Flashcards by Amanda Lydic

Sacromere??

contractile units in myofibrils

- defined as z-line to z-line

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Myofibrils??

contained within each muscle cell

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What surrounds each muscle fiber?

endomysium

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What is a fasiculi??

bundle of muscle fibers

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What surrounds a fasiculus??

perimysium

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What surrounds the whole muscle and coalesces with the CT, becoming part of the tendon?

epimysium

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Between efferent nerve fibers and afferent nerve fibers, what percentage goes with each?

60% efferent

40% afferent

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What things are efferent nerve fibers?

alpha motor neurons

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What things are afferent nerve fibers?

mechanoreceptors and chemoreceptors

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What is a triad??

cisternae and t-tubule and cisternae

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Cisternae

assoc. w/ Ca2+ release
longitundinal or light SR
Ca2+ reuptake = Ca2+ binds to calsequestrin

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Calsequestrin??

binding protein, reduces gradient

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Optimal length of z-line to z-line??

2.0-2.2 micrometers

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How many actin filaments will one myosin filament interact with??

6 actin filaments

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Titin??

acts like anchor and spring

keeps myosin filament in place

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Rebulin??

molecular ruler in assembly of actin

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Dystrophin??

anchors contractile proteins to the cellular membrane

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Alpha-actinin??

located in the z-line and connects actin filaments together

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Motor unit??

innervates one or more muscle fibers

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All muscle fibers connected to motor unit have:

same contractile properties

same metabolic properties

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What does DHP do??

Blocks voltage sensitive Ca2+ channel

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What does Ryanodine do??

blocks Ca2+ release channel

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T/F: Z-line gets bigger during contraction

False.

It gets smaller

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T/F: H zone and I zone get smaller during contraction

True

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T/F: The A band does not change length during contraction??

TRUE

What is the A band made of?

thin filaments(actin) and thick filaments(myosin)

What does the hinge region do??

active in coupling chemical to mechanical energy

Isoenzymes for Myosin Thick Filaments

1. fast-fast twitch = locomotion | 2. slow-slow twitch = postural

Length of an actin thin filament??

one micrometer

what does the z-line equal??

alpha-actin

Tropin I (TN-I)??

inhibits active binding site

Tropin C (TN-C)??

contains binding site for Ca2+

Tropin T (TN-T)??

binds to tropomyosin

Fine motor control = ________ amount of innervation

greater

A lesser amount of innervation is assoc. with?

gross motor control

T/F: Muscle spindles run parallel w/ extrafusal fibers??

True

Primary annulospinal ending??

quick responders to changes in muscle length (dynamic)

Secondary flower-spray endings??

tonic input to muscle length (static)

What does acetylcholinesterase do??

cleaves off Ach

Ach binding to the motor end plate leads to what??

Na+ influxes via gated cation channels depolarization (end plate potential) EEP comes out of cleft and starts AP across cell membrane

T/F: Golgi tendon organ set in series w/ muscle fibers??

True

What determines the speed of contractions?

Myosin ATP found on thick filament

What determines the speed of relaxation? Is energy involved?

Ca2+ pumped back into SR at a rate of Ca2+/ATP It is energy dependent!

Series Elastic Elements

tendon | hinge region

Contractile Elements

sarcomeres

Parallel Elastic Elements

sarcolemmas blood vessels and nerves CT

Types of Muscle Contraction

isometric | isotonic

Force of weight > force being produced by muscle??

Weight doesn't move (Isometric)

Force being produced by muscle > force of weight??

Muscle shortens and weight moves (Isotonic)

What is the total force production dependent on??

the cross-sectional area of the muscle INDEPENDENT OF MUSCLE FIBER TYPE!!

What does maximal velocity of contraction depend on??

cross bridge cycling

Temporal summation?

frequency of firing of an alpha-motor neuron

Spatial summation?

recruitment of different alpha-motor neurons

What are the additive colors? What do they add up to?

RGB Add up to white

What are the subtractive colors? What do they subtract to?

CMYK (Cyan Magenta Yellow Black) Subtract to black

Is the focal distance for convex lens positive or negative?

positive

Is the focal distance for concave lens positive or negative?

negative

What is emmetropia?

normal vision for far objects NO ACCOMMODATION!!!!

4 things about emmetropia

- far objects (>7m) - ciliary muscles relaxed - zonular fibers under tension - lens flattened

4 things about accommodation

- near objects - ciliary muscle contracted - zonular fibers relaxed - lens rounded

Presbyopia

- d/t: aging - stiff lens - reduced accommodation - correction: reading glasses or bifocals Far: Clear Near: Blurry Convex lens needed

Hyperopia

- d/t: farsighted - bulbus too short - correction: reading glasses or bifocals Far: Clear Near: Blurry -Convex lens needed

Myopia

- d/t: nearsighted - bulbus too long - correction: driving glasses or bifocals Far: Blurry Near: Clear -Concave lens needed

Cornea epithelium

- barrier between tear fluid and stroma - multi-layer epithelium - cells regenerate (turnover: 7 days) - active ion transport necessary to maintain transparency of stroma

Cornea endothelium

- barrier between stroma and aqueous humor - single layer epithelium - cells DO NOT regenerate (can stretch to maintain barrier) - active ion transport necessary to maintain stroma transparency - active transport prevents swelling of stroma. swelling leads to loss of transparency and clouding of cornea

CN involved with Gustation

CN VII = facial nerve; taste buds on tip of tongue CN IX = glossopharyngeal nerve; taste buds on back of tongue CN X = vagus nerve; taste buds on epiglottis

What are the 6 tastes?

sweet, salty, bitter, sour, umami, fatty

What does flavor add to taste?

smell, temperature, pungency, freshness, and texture

Type I taste receptor cells

Glia cells - ensheathe Type II cells - express exto-ATPase to limit extracellular ATP

Type II taste receptor cells

Receptor cells - subset for sweet, umami, bitter, and possibly fatty - release ATP via channels in response to ligand

Type III taste receptor cells

Presynaptic cells - subtypes for salty and acid taste - release serotonin and norepinephrine in response to activation - DO FORM SYNAPSES w/ gustatory afferents!

Type IV taste receptor cells

Basal cells | -stem cells for taste bud regeneration taste cell turnover: 2 weeks