Muscle tissue Flashcards by katerin V Ascencio

T/F Contractility is the key feature of muscle

TRUE

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Sarcolemma

Muscle cell membrane

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Sarcoplasm

Is the cytoplasm of muscle

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Skeletal Muscle

-Elongated, large, multinucleated fibers. Strong quick and voluntary contractions

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Cardiac muscle

-Irregular branched cells bound together longitudinally by intercalated discs. Strong involuntary contractions

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Smooth muscle

Grouped, fusiform cells. Weak involuntary contractions

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Longitudinal section in skeletal muscle are separated by

-Very thin endomysium that includes fibroblast nucleus

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Muscle nuclei are found

against sarcolemma

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Each fiber has three of four

Myofibrils whose striations are slightly out of alignment

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Myofibrils

Cylindrical bundles of thick and thin myofilaments

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Cardiac muscles are bound together by

Intercalated discs. They have centrally located nuclei.

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A fiber consists of cells in a series joined at interdigitating regions called

Intercalated discs

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Transverse regions of the intercalated discs have

Abundant desmosomes and adherent junctions

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Longitudinal discs have

Gap junctions to allow exchange of ions

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Electric synapses

promoting rapid impulse conduction through many cardiac cells and contraction of many adjacent cells

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Impulses of heartbeat are initiated, regulated, and coordinated by

Nodes of myocardial fibers

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Contraction of individual myocardial fibers

All-or-none

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Nerve fibers that accelerate heartbeat

Sympathetic

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Nerve fibers that decrease heartbeat

Parasympathetic

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Ischemia

Damage to tissue due to lack of oxygen

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Adult mammal heart muscle has little potential to regenerate because

It lacks satellite cells

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Smooth muscle is specialized for

involuntary slow, steady contractions under the influence of autonomic nerves

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Smooth muscle forms a major component of what tracts?

Digestive, respiratory, urinary, and reproductive, blood vessels and their organs.

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What allows multicellular tissue to contract as a unit in smooth muscle?

Thin filaments attached to dense bodies located at the cell membare

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Which muscle tissue does not have all or noting contractions?

Smooth muscle

Fibers of skeletal muscle tissue

Single multinucleate cells in parallel

Cell shape of skeletal muscle tissue

Cylindrical cells, many cm lomg

Does skeletal muscle tissue have striations present?

Yes

What is the connective tissue of skeletal muscle?

endomysium, perimysium, epimysium

Locations of skeletal muscle tissue

skeletal muscles, tongue, eye, diaphragm

Key function of skeletal connective tissue

Voluntary

what is the only tissue with motor innervation?

Skeletal. Smooth and cardiac are autonomic

Contractions of skeletal muscle tissue

all or none, starting at the motor end plate

skeletal muscle response to increase overload

hypertrophy

Regeneration ability of skeletal muscle

Limited

Cardiac fibers

cells aligned in branching pattern

Cell shape of cardiac cells

cylindrical 50-100 micrometers long

Are striations present in cardiac muscle

yes

Special structures of cardiac muscle tissue

Intercalated discs

The connective tissue of cardiac

endomysium

Location of cardiac tissue

heart

key function of cardiac tissue

Involuntary (pumping of heart)

Contraction of cardiac muscles

all or none but, intrinsic

Response of cardiac tissue to increase overload

hypertrophy

regeneration ability of cardiac tissue

very poor

Fibers of smooth muscle tissue

single, small, closely pack fusiform cells

cell shape of smooth muscle

fusiform cells

does smooth muscle have striations

no they're absent

Special features of smooth muscle

dense bodies

Connective tissue of smooth muscle

endomysium

Locations of smooth muscle

digestive, urinary, respiratory tracts, blood vessels, uterus, bladder, and other organs.

Key function of smooth muscle

involuntary

contractions of smooth muscle

partial, slow, and wavelike

response of smooth muscle to increase load

hypertophy and hyperplasia

Regeneration ability of smooth muscle

Good

Endomysium

surrounds individual muscles, include fibroblast muscle

Paramysium

surrounds a group of muscle fibers called fascicle

Epismysium

surrounds entire muscle

where is muscle nuclei found

against sarcolemma

3 to 4 myofibrils in each muscle fiber are composed of

myofilaments that fill each muscle fiber

Cardiac muscle is connected together by

intercalated discs

where is nuclei in cardiac muscle

centrally located

transverse regions have

desosomes and adherent junctions

longitudinal regions have

gap junctions

Electrical synapses

efficient contraction mechanism that produce conduction between cells and contraction of adjacent cells

Fiber contractions are

intrinsic and spontaneous

what do nodes of myocardiac fibers do

initiate, coordinate, and control heartbeat

Individual myocardial fibers have what kind of contraction

all or none

Sympathetic

increases rate of heartbeat

parasympathetic

decreases rate of heartbeat

ischemia

damage to tissue due to lack of oxygen

Smooth muscle has attachment to

dense bodies so multiple tissue can work together more efficiently as a unit

Within fascicles individual muscle fibers are wrapped by

endomysium

myotendinouns junction

tendons develop together with skeletal muscle and they joint muscle at the periosteum of bones

development of skeletal muscle

myoblast fuse to make longer tubes myotubes make proteins to make myofilaments

satellite cells

myoblast cells that don't fuse or differentiate, instead they proliferate and act when there's injury

myofibrils are separated into sarcomeres by

z discs

thick filaments are a bundle of myosin connected by

titin

thick filaments span the entire

A band and bind to proteins to the M line and the Z discs

myofilaments are composed of

thick and thin filaments consisting of contractile protein regions

thick filaments contain

multiple myosin bundles

thin filaments contain

actin, troponin, and tropomyosin

what happens at contraction?

-nerve impulses release acetytoalcholine across the membrane which reacts with muscle impulses (depolarization) resulting in the release of Ca++ from sarcoplasmic reticulum -Ca++ binds to troponin changing tropomyosin and allowing myosin heads to bind to actin forming cross bridges between thick and thin filaments -myosin head pivots as ATP releases energy which pulls thin filaments along thick filaments

Myasthenia gravis

autoimmune disease that creates antibodies against acytoalcholine receptors leading to muscle weakness

Duchenne muscular dystrophy

Mutation of the dystrophin gene can lead to deffective linkages between the cytoskeletal and the ECM. Muscle contraction can break these linkages causin atrophy of muscle fibers

Dystrophin

actin-binding protein involved in function of mycrofibrils

Two types of receptors in muscle

muscle spindle and Golgi tendon organs

Muscle spindle contractions begins in response to

stress

i5 to 15 intrafulsal muscle fibers are associated with

sensory and motor nerve fibers

Golgi tendon organs

detect changes in contraction and they inhibit contraction if it becomes too much

Slow oxidative

stain the darkest and have highest ATP activity

Fast glyocolitc

stain the lightest and have the lowest ATP activity

Fast oxidative-glycolytic

Middle ground between slow oxidative and fast glycolitic

Muscle tissue Flashcards

(93 cards)