Chapter 11 - Muscle Tissue Flashcards by Ashlyn Laidman

What is the primary role of muscle?

Contraction

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What are the two types of contractile cell apperances?

Striated
Smooth

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Muscle cells are characterized by aggregates of elongated cells arranged in parallel array

True

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What are the two types of myofilaments in muscle cells?

Actin
Myosin

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Skeletal muscle characteristics

Light and dark staining cells

Muscle fibers

Multinucleated myocytes

Voluntary, strong, discontinuous movements

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Cardiac Muscle Characteristics

Light and dark staining

individual myocytes

Interculated discs

Nucli centrally located

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Smooth Muscle Characteristics

Tappered Ends

Central Nucli

Oblique angles connect filaments to the membrane

weak, slow, involuntary movements

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Where is smooth muscle located (2)?

Visceral Organs

Blood Vessels

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What are the 3 layers of CT in skeletal muscle?

Epimysium
Perimysium
Endomysium

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What does the epimysium surround?

Surronds collection of fascicles of skeletal muscle

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What does the perimysium surrond?

Surronds group of fibers to form a bundle (fascicle) in skeletal fibers

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What does the endomysium surround?

Surronds muslce fibers in skeletal and other muscle types

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What do the layers of CT help the skeletal muscle do?

The CT helps transmitt force as 1 section

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What type of fibers are prevalent in the CT in skeletal muscle?

Reticular fibers

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What is a muscle fiber?

A skeletal muscle cell

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What are the three types of skeletal muslce?

Type I

Type IIa

Type IIb

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What are the characteristics of type I skeletal muscle fibers?

Red, Slow

Oxidative phosphorylation

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Why does oxidative phosphorylation help the muscle with long standing contractions?

Decreases waste production (in comparison to glycolysis) so the muscle doesn’t tire out

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What are the characteristics of type IIa skeletal muscle fibers?

Oxydative phosphoylation and glycolysis

Get some byproducts

Decrease endurance, increase in speed

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What are the characteristics of type IIb muscle fibers?

Fast movements

Glycolysis

Increase waste products

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What type of animals/where doe you find type I skeletal muscle?

Limbs of mammals

Migratory birds

Back Muscles

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Where do you find/what type of person type IIa skeletal muscle fiber?

Middle-distance swimmers

Hockey players

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What type of athletes do you find type IIb skeletal muscle fibers?

Sprinters

Weightlifters

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What is the subunit of muscle fibers?

Myofibrils

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What are myofibrils composed of?

myofilaments

The organization of ______ in muscle fibers give a cross-striated apperance

Myofibrils

A-band

Thick and thin overlap

I band

Thin band only

Z line

Bisects the I band

Sarcomere

Z line to Z line

What are alpha actininins responsbile for?

Help attach actin to the Z line

H band

Just myosin filaments

M line

In the H band Most high density

What is titin? What is its function?

Protien Attaches myosin to the Z line so they stay in register

What is tropomyosin? What is its function?

Protien Helical Mask myosin binding site on actin

When muscles contract and relax what band(s) shrink/grow? What band(s) never change?

I band and H band increase during stretch A band never changes

What are the three parts of the troponin complex?

TnC TnT TnI

What is the function of TnC?

Binds calcium Initiates contraction

What is the function of TnT?

Binds direclty to tropomyosin

What is the function of TnI?

Inhibits the interaction

What happens when Ca binds to TnC?

There is a shift in TnT and thereby a shift in TnI

What happens in a neuromuscular junction?

Motor nueron terminate on skeletal muscle

What is the path the action potential takes from a neuromuscular junction till muscle contraction?

AP \> depolarization of sarcolema \> t-tubules depolarize \> adjacent to terminal cisterma of sarcoplasmic reticulum \> release Ca from cisterna

What is the sarcolema?

Membrane on muscle

What kind of arrangements do myosin filaments have in skeletal muscle?

Bipolar arrangment All heads face one direction

Where do you find bipolar arrangment of mysoin?

Skeletal fibers Cardiac fibers

What two types of binding sites are on myosin heads?

1. Actin binding site 2. ATP binding site

What is the process from when calcium is released to the myosin heads actually causing contraction?

Calcium released \> myosin binding site is exposed \> myosin binds to actin = rigor conformation \> ATP binds myosin head \> release myosin head \> Hydrolysis of ATP \> release of inorganic phosphate = stroke power \> myosin head moves \> release of ATP \> back to the beginning

What is the neurotransmitter that is released in neurotransmitter junction?

AcH

What is botulism toxin? What does it do?

It prevents the release of AcH to the neuromuscular junction Flacid Paralysis

What is tetnus toxin? What does it do?

No inhibitory neurons \> sustained release of AcH Lock Jaw, cortusion of muscle contractions

What are intercalated discs? What muscle types are they found in?

Found in cardiac muscle Gap junctions that link cardiac muscle cells

\_\_\_\_\_\_\_\_\_ muscle fibers consist of numerous cells arranged end to end

Cardiac muscle

How many nucli do cardiac cells have?

One - mononucleated

Where is cardiac muscle located?

Myocardium

What are the three layers of heart?

Epicardium Myocardium Endocardium

What are the two components of intercalated discs of cardiac muscle?

Transverse Component Lateral Component

What are the two components of the transverse component of the intercalated discs?

1. Fascia adherens 2. Maculae adherens

Does the transverse component of the intercalated disc run parallel or perpendicular to the myofibrils?

Perpendicular to myofibrils

What are the two components of the lateral component of the intercalated disc?

Gap junctions maculae adherens

Do lateral component of the intercalated disc run parallel or perpendicular to myofibrils?

Parallel to myofibirls

What are t-tubules?

Extension of sarcolema and interact with terminal cisterma

How does the parasympathetic and sympathetic systems effect the heart?

They control the bpm - heart rate Sympathetic: increase bpm Parasympathetic: decrease bpm

Cardiac conducting cells - function

Spontaneously contract

How does the electriv current travel through the heart?

SA node \> AV node \> radiate through bundle of his \> purkinje fibers

What kind of cells are in the subendocardium?

Cardiac contractile cells

What is a myocardial infraction?

Heart attack Occlusion/blockage of artery = myocardial ischemia

What are the stages of myocardial infarction?

Blockage of artery \> intercalated discs disappear \> nucli condense = hypnotic \> 3 days later = necrosis

What occurs during necrosis?

Occurs 3 days after a heart attack Immune cells break down necrotic tissue Develop scar tissue \> heart no longer contracting normally

How do smooth muscles contract? (what style)

Twist, like a corkscrew Not accordian (like cardiac and skeletal muscle) Twisted nucli

What are dense bodies? What muscle type are they located in? What is thier function?

Anchor thin filamemts and intermediate filaments to the sarcolemma Transmit contractile forces generated inside cell to cell surface Located in smooth muscle

What are dense bodies made of?

Alpha actininin

What are dense bodies analogous to in skeletal and cardiac muscle?

Z line

What is the myosin arrangment in smooth muscle?

Side-polar Contributes to the twisting motion of smooth muscle cells

What triggers smooth muscle contractions?

Not controlled by nervous system Triggered by mechanical, chemical, and electrical stimuli

What is the process of contraction in smooth cells?

Calcium is released \> calcium binds to calmodulin \> calcium-calmodulin complex activated MLCK \> phosphorylate mysoin \> binding of actin

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Skeletal Muscle

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Smooth Muscle

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Cardiac Muscle

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Skeletal Muscle

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Cardiac Muscle

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Smooth Muscle

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Myofibril Muscle fasicle Muscle fiber Epimysium Endomysium Perimysium

Identify the 2 skeletal muscle types

Dark Stain - type I Light Stain - type II

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I band A band Z line Sarcomere

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I band A Band H band Z line

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Tropomyosin Actin Ca binding site Troponin Complex Binding site blocked - no contraction Myosin Binding Site Binding site exposed - contraction

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Sarcolemma Z line H band Z line T tubule Terminal cisterna of sarcoplasmic reticulum

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Motor Neuron Axon Action Potential Neuromuscular Junction Mitochondrion T tubule Sarcoplasmic Reticulum Myofibril Plasma Membrane of Muscle Fiber Sarcomere Ca released

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