UNLV KIN 223 CHAPTER 10: MUSCLE TISSUE

Which of the following is NOT one of the five general functions of muscle tissue?

- producing movement

- maintaining body position and posture

- storing and releasing hormones

- generating heat

Storing and Releasing Hormones

What are the 5 main functions of Muscular Tissue? (M, MP, P+S, R, PH)

Moves the Body

maintains posture

protect and support

regulate elimination of materials

produces heat

How does skeletal muscle move the body?

A) By contracting and pulling on bones via tendons

B) By pushing bones away from each other

C) By expanding to create movement

D) By generating electrical impulses that move joints

A) By contracting and pulling on bones via tendons

How does skeletal muscle help maintain posture?

A) By continuously making small contractions keep body up and balanced

B) By remaining completely relaxed until movement is needed

C) By storing calcium for bone strength

D) By pumping blood throughout the body

A) By continuously making small contractions keep body up and balanced

How does skeletal muscle contribute to protection and support in the body?

A) By forming a rigid shield around vital organs

B) By contracting to cushion and stabilize internal structures and protects +covers important organs

C) By producing white blood cells to fight infections

D) By directly strengthening bone density

B) By contracting to cushion and stabilize internal structures and protects +covers important organs

How does skeletal muscle regulate the elimination of materials in the body?

- By absorbing excess fluids and waste products

- By producing enzymes that break down waste materials

- By filtering toxins directly from the bloodstream

- By contracting and relaxing sphincters to control the passage of substances

- By contracting and relaxing sphincters to control the passage of substances

How does skeletal muscle contribute to heat production in the body?

- By storing heat within the muscle fibers

- Through involuntary contractions such as shivering

- By absorbing heat from surrounding tissues

- Through the production of sweat during movement

- Through involuntary contractions such as shivering

Which of the following is NOT one of the five main characteristics of skeletal muscle?

A) Excitability (responsiveness)

B) Contractility (ability to shorten)

C) Elasticity (ability to return to original shape)

D) Mineral storage for bone growth

E) Extensibility (ability to stretch)

D) Mineral storage for bone growth

Why is extensibility an important characteristic of skeletal muscle?

A) It allows muscles to generate heat through contraction.

B) It enables muscles to be stretched without being damaged.

C) It helps muscles contract with greater force.

D) It allows muscles to store energy for later use.

B) It enables muscles to be stretched without being damaged.

Why is excitability an important characteristic of skeletal muscle?

A) It allows muscles to stretch beyond their normal length.

B) It enables muscles to respond to nerve signals and generate contractions.

C) It helps muscles return to their original shape after contraction.

D) It allows muscles to store and release calcium for bone health.

B) It enables muscles to respond to a stimulus and generate contractions.

Why is conductivity an important characteristic of skeletal muscle?

A) It allows muscles to generate new muscle fibers when damaged.

B) It helps muscles store and release calcium for bone health.

C) It enables the transmission of electrical impulses across the muscle, leading to contraction.

D) It allows muscles to resist fatigue during prolonged activity.

C) It enables the transmission of electrical impulses across the muscle, leading to contraction.

Why is contractility considered a characteristic of skeletal muscle?

A) It allows skeletal muscles to stretch and return to their original length.

B) It helps skeletal muscles resist damage from excessive use.

C) It allows skeletal muscles to store energy for future use.

D) It enables skeletal muscles to contract and make movement

D) It enables skeletal muscles to contract and make movement

Why is elasticity considered a characteristic of skeletal muscle?

It allows skeletal muscles to contract more forcefully.

It helps skeletal muscles store energy during contractions.

It enables skeletal muscles to return to their original shape after being stretched or contracted.

It allows skeletal muscles to maintain a constant temperature during activity.

It allows skeletal muscles to return to their original shape after being stretched or contracted.

Skeletal Muscle is an _____; which is a collection of different tissues that work together

Organ

Fibers of the skeletal muscle are bundles within a _______

Fascicle

What is the role of fascicles within a skeletal muscle?

- They contain blood vessels and nerves that supply the muscle tissue.

- They generate electrical impulses that stimulate muscle contraction.

- They divide the muscle into smaller, functional units that allow for more precise movements.

- They store calcium ions for muscle contraction.

They divide the muscle into smaller, functional units that allow for more precise movements.

Are skeletal muscle fibers voluntary muscles or involuntary muscles?

Voluntary Muscles

What are the 3 CT components of Skeletal Muscle? From most superficial to least

Epimysium, Perimysium, and Endomysium

The ________ is a layer of Dense Irregular (fibrous) Tissue that wraps around the whole muscle to provide structural support

Epimysium

The________ is made up of Areolar CT that surrounds each individual muscle fiber.

- delicate layer for electrical insulation, capillary support, and binding of neighboring cells

- electrically involves muscle fibers

Endomysium

The _______ is made of Dense Irregular CT that wraps around each fascicle

- functions to protect and support each fascicle

- houses many blood vessels and nerves

Perimysium

The attachment of a muscle or bone can either be a ______ or ________

Tendon; Aponeuroses

A _____ is a thick, cordlike structure that is made of Dense Regular CT that connects muscle to bone and the fibers go in the same dirrection

Tendon

A _________ is a thin, flattened sheet that is made up of Dense Irregular CT and the fibers blend in together

Aponeurosis

The ______ ______ is:

- made of dense irregular CT

- superficial to epimysium

- separates individual muscles

- binds muscles with similar functions

Deep Fascia

What is the primary function of deep fascia in skeletal muscle tissue?

- To connect muscle to bone and allow for movement

- To provide the energy required for muscle contraction

- To produce red blood cells for the muscle tissue

- To separate individual muscles and group them into functional units

- To separate individual muscles and group them into functional units

_______ ______ is made of Areolar + Adipose CT and is superficial to Deep Fascia. It separates the muscles from the skin and is closer to the skin

Superficial Fascia

What is the primary function of the superficial fascia in the body?

A) To connect muscles to bones

B) To store and release energy during muscle contraction

C) To provide a protective layer of connective tissue beneath the skin, storing fat and facilitating movement

D) To transmit electrical impulses between muscles

C) To provide a protective layer of connective tissue beneath the skin, storing fat and facilitating movement

________ ______ are highly vascularized in Skeletal Muscle fibers and travels through all three of the of the muscle layers.

Blood Vessels

What is the role of blood vessels in skeletal muscle fibers?

- To store oxygen and nutrients for the muscle?

- To increase muscle contraction strength

- To deliver oxygen and nutrients, and remove waste products

- To produce energy for muscle movement

- To deliver oxygen and nutrients, and remove waste products

_______ are innervated by motor neurons of the somatic nervous system and extend from the brain and spinal cord to Skeletal Muscle Fibers

Nerves

What is the role of nerves in skeletal muscle fibers?

A) To supply oxygen to muscle fibers

B) To carry electrical signals that trigger muscle contraction

C) To store calcium ions for muscle function

D) To protect muscles from injury during exercise

B) To carry electrical signals that trigger muscle contraction

What is the role of somatic motor neurons in relation to skeletal muscle fibers?

- They deliver oxygen and nutrients to the muscle fibers

- they store calcium ions for muscle contraction

- they transmit electrical impulses that initiate muscle contraction

- They provide structural support to muscle fibers during movement

- they transmit electrical impulses that initiate muscle contraction

What is the role of Axons in the nerve fibers of skeletal muscle?

A) To transmit electrical impulses from the brain to the muscle fibers, initiating contraction

B) To provide structural support to the muscle fibers

C) To store neurotransmitters for muscle relaxation

D) To maintain the integrity of muscle fiber membranes

A) To transmit electrical impulses from the brain to the muscle fibers, triggers a contraction

A multinucleated cell has _______ nuclei

Multiple

Why are skeletal muscle fibers multinucleated?

A) To allow for greater flexibility in muscle movement

B) To enable faster electrical impulses along the muscle fibers

C) To support the large size of the muscle fibers and facilitate efficient protein synthesis

D) To prevent muscle fibers from contracting too much

C) To support the large size of the muscle fibers and facilitate efficient protein synthesis

Muscle fibers are _____ and _____ and runs the full length of the muscle

Long; Wide

What is the role of myoblasts in the formation of skeletal muscle fibers?

A) They produce the collagen that forms the muscle's connective tissue.

B) They fuse together to form multinucleated skeletal muscle fibers during development.

C) They generate the electrical impulses that stimulate muscle contraction.

D) They secrete the enzymes required for muscle relaxation after contraction.

B) They fuse together to form multinucleated skeletal muscle fibers during development.

If myoblasts dont fuse together, they stay as ______ ______ _____ (sattelite cells)

Adult Stem Cells

What is the primary function of adult stem cells in skeletal muscle fibers?

A) To produce energy for muscle contractions

B) To repair and regenerate damaged muscle tissue

C) To store calcium ions for muscle contraction

D) To provide structural support for muscle fibers

B) To repair and regenerate damaged muscle tissue

What is the role of the sarcolemma in skeletal muscle fibers?

- conducts electrical impulses to stimulate muscle contraction

- it stores calcium ions for muscle contraction

- it provides energy for muscle fibers during contraction

- it connects muscle fibers to the bone

- conducts electrical impulses to stimulate muscle contraction

The Sarcolemma serves as a muscle cells ______ _______ as compared to in cells.

Plasma Membrane

__- _____ are Tiny channels within the sarcolemma that spreads signals fast

- lets calcium in to do work

- Extends deep into the cell and connects to the endoplasmic reticulum

- contains voltage sensitive calcium channels

T-Tubules or Transverse Tubules

What is the primary function of the sarcoplasm in skeletal muscle fibers?

A) To store calcium ions needed for muscle contraction

B) To provide structural support to the muscle fibers

C) To contain glycogen and myoglobin, providing energy and oxygen for muscle contraction

D) To transmit electrical impulses that trigger muscle contraction

C) To contain glycogen and myoglobin, providing energy and oxygen for muscle contraction

The _______ has a voltage-gated ion channel that allows for conduction of electrical signals

Sarcolemma

In the Sarcolemma, the voltage gated Na+ channel lets Na+ _____ and the voltage gated K+ channel lets K+ _____

In; Out

What is the primary function of myofibrils in skeletal muscle fibers?

A) To store calcium ions for muscle contraction

B) To generate electrical impulses for muscle contraction

C) To facilitate the contraction of muscle fibers through the interaction of actin and myosin filaments

D) To provide structural support to the muscle fibers

C) To facilitate the contraction of muscle fibers through the interaction of actin and myosin filaments

Myofibrils are surrounded by the _______ ________

Sarcoplasmic Reticulum

Each myofibril is composed of bundles of ______ and is enclosed in portions of the sarcoplasmic reticulum

Myofilaments

What is the primary function of the sarcoplasmic reticulum in skeletal muscle fibers?

A) To generate electrical impulses for muscle contraction

B) To store and release calcium ions necessary for muscle contraction

C) To provide energy for muscle contraction

D) To synthesize proteins for muscle growth

B) To store and release calcium ions necessary for muscle contraction

How does the sarcoplasmic reticulum contribute to the process of muscle contraction?

A) It produces ATP for muscle fibers

B) It stores oxygen to fuel muscle contractions

C) It connects muscle fibers to bones

D) It releases calcium ions, which trigger the interaction between actin and myosin

D) It releases calcium ions, which trigger the interaction between actin and myosin

_______ _______ are the blind sacs of the sarcoplasmic reticulum

Terminal Cisternae

What is the primary function of the terminal cisternae in skeletal muscle fibers?

A) Serves as a reservoir for calcium ions

B) To generate electrical impulses for muscle contraction

C) To produce ATP for muscle energy

D) To connect muscle fibers to tendons

A) Serves as a reservoir for calcium ions

What three structures make up the triad in a skeletal muscle fiber?

A) One sarcolemma and two mitochondria

B) One T-tubule and two terminal cisternae of the sarcoplasmic reticulum

C) One myofibril and two Z-discs

D) One motor neuron and two neuromuscular junctions

B) One T-tubule and two terminal cisternae of the sarcoplasmic reticulum

What is the function of the triad in skeletal muscle fibers?

- It stores ATP for muscle contractions.

- It provides structural support to the sarcomere.

- It connects muscle fibers to tendons for force transmission.

- It facilitates the rapid transmission of action potentials and the release of calcium for contraction.

It facilitates the rapid transmission of action potentials and the release of calcium for contraction.

What is the primary function of Ca²⁺ pumps in skeletal muscle fibers?

A) To release calcium into the sarcoplasm to trigger muscle contraction

B) To transport calcium back into the sarcoplasmic reticulum for muscle relaxation

C) To generate ATP for muscle contractions

D) To break down neurotransmitters at the neuromuscular junction

B) To transport calcium back into the sarcoplasmic reticulum for muscle relaxation

Where are the Ca²⁺ pumps primarily located in skeletal muscle fibers?

A) In the myosin filaments

B) In the T-tubules

C) In the sarcoplasmic reticulum membrane

D) In the neuromuscular junction

C) In the sarcoplasmic reticulum membrane

_______ binds to calmodulin and calsequestrin

Calcium

What is the primary function of calcium release channels in skeletal muscle fibers?

A) To transport oxygen to muscle cells

B) To generate ATP for muscle movement

C) To release calcium from the sarcoplasmic reticulum, triggering muscle contraction

D) To remove excess calcium from the muscle cell after contraction

C) To release calcium from the sarcoplasmic reticulum, triggering muscle contraction

Where are the calcium release channels primarily located in skeletal muscle fibers?

A) In the sarcolemma

B) In the mitochondria

C) In the sarcoplasmic reticulum

D) In the neuromuscular junction

C) In the sarcoplasmic reticulum

What triggers the release of calcium from the sarcoplasmic reticulum in skeletal muscle fibers?

A) The binding of ATP to myosin heads

B) The passive diffusion of calcium through the plasma membrane

C) The breakdown of acetylcholine in the synaptic cleft

D) The arrival of an action potential at the muscle fiber's T-tubules

D) The arrival of an action potential at the muscle fiber's T-tubules

What is the primary function of myofilaments in skeletal muscle fibers?

A) To store calcium for muscle contraction

B) To generate force by sliding past each other during contraction

C) To provide energy for muscle movement

D) To carry oxygen to muscle cells

B) To generate force by sliding past each other during contraction

Which two types of myofilaments are responsible for muscle contraction?

A) Actin and myosin

B) Troponin and tropomyosin

C) Collagen and elastin

D) Myoglobin and hemoglobin

A) Actin and myosin

"My oh my, you are so thick" is a mnemonic device to remember that _____ if for ______ filaments

Myosin; Thick

" Why are you actin so thin?" is a mnemonic device to remember that _____ if for ______ filaments

Actin; Thin

How do thick and thin myofilaments interact to produce muscle contraction?

A) Thick filaments stretch thin filaments to generate movement.

B) Thin filaments push thick filaments apart to create force.

C) Thick filaments (myosin) pull thin filaments (actin) toward the center of the sarcomere, shortening the muscle.

D) Thin filaments (actin) release energy to activate thick filaments (myosin).

C) Thick filaments (myosin) pull thin filaments (actin) toward the center of the sarcomere, shortening the muscle.

Which of the following structures is directly responsible for the movement of thick filaments during muscle contraction?

A) Sarcoplasmic reticulum

B) Myosin heads

C) T-tubules

D) Z-discs

B) Myosin heads

How do thick filaments contribute to muscle contraction?

A) They bind to calcium ions to initiate contraction.

B) They interact with thin filaments to generate force by forming cross-bridges.

C) They store ATP for energy release during contraction.

D) They transmit electrical signals to muscle fibers.

B) They interact with thin filaments to generate force by forming cross-bridges.

What are the primary proteins that make up the thin filaments in skeletal muscle fibers?

A) Myosin, Troponin, and Tropomyosin

B) Actin, Troponin, and Tropomyosin

C) Actin, Myosin, and Titin

D) Tropomyosin, Myosin, and Dystrophin

B) Actin, Troponin, and Tropomyosin

What is the role of tropomyosin in the thin filaments of skeletal muscle fibers?

A) It binds ATP to provide energy for muscle contraction.

B) It blocks the active sites on actin, preventing myosin from binding when the muscle is at rest.

C) It stores calcium ions for muscle contraction.

D) It generates force by pulling on thick filaments.

B) It blocks the active sites on actin, preventing myosin from binding when the muscle is at rest.

How do thin filaments contribute to muscle contraction?

A) They release calcium ions to trigger contraction

.B) They slide past thick filaments, shortening the sarcomere.

C) They generate force by pulling on the thick filaments.

D) They provide structural support to the muscle fiber.

.B) They slide past thick filaments, shortening the sarcomere.

Which of the following are the primary regulatory proteins in skeletal muscle fibers?

A) Actin and myosin

B) Troponin and tropomyosin

C) Titin and dystrophin

D) Myoglobin and creatine kinase

B) Troponin and tropomyosin

How does troponin contribute to muscle contraction?

A) It changes shape when calcium binds to it, moving tropomyosin and exposing myosin-binding sites on actin.

B) It binds to ATP and provides energy for contraction.

C) It forms cross-bridges with myosin to generate force.

D) It stabilizes the sarcomere during muscle relaxation.

A) It changes shape when calcium binds to it, moving tropomyosin and exposing myosin-binding sites on actin.

What is the role of tropomyosin in skeletal muscle contraction?

A) It binds calcium ions to initiate contraction.

B) It blocks the myosin-binding sites on actin when the muscle is relaxed.

C) It breaks down ATP to provide energy for contraction.

D) It transmits nerve signals to the muscle fibers.

B) It blocks the myosin-binding sites on actin when the muscle is relaxed.

What is the basic structural unit of a skeletal muscle fiber responsible for contraction?

- Myosin filament

- Fascicle

- Sarcomere

- Myofibril

- Sarcomere

What occurs during muscle contraction at the level of the sarcomere?

A) The Z-discs move farther apart, lengthening the sarcomere.

B) The actin and myosin filaments slide past each other, shortening the sarcomere.

C) The myosin filaments contract while the actin filaments remain stationary.

D) The sarcomere lengthens, causing muscle extension.

B) The actin and myosin filaments slide past each other, shortening the sarcomere.

Each sarcomere is composed of overlapping .....

Thick and Thin Filaments

What is the role of the Z disc in skeletal muscle fibers?

A) It anchors the thin (actin) filaments and defines the separates sarcomeres.

B) It stores calcium ions for muscle contraction.

C) It generates electrical impulses to trigger muscle contraction.

D) It connects muscle fibers to tendons.

A) It anchors the thin (actin) filaments and defines the separates sarcomeres.

Which of the following is true about the I bands in skeletal muscle fibers?

A) They shorten during muscle contraction.

B) They contain both actin and myosin filaments in equal proportions.

C) They are located in the center of the sarcomere.

D) They consist only of actin (thin) filaments and appear lighter under a microscope.

D) They consist only of actin (thin) filaments and appear lighter under a microscope.

What is the primary characteristic of the A bands in skeletal muscle fibers?

A) They contain only thin filaments.

B) They are the regions where actin (thin) and myosin (thick) filaments overlap.

C) They are the lightest bands in the muscle fiber.

D) They are the regions where only myosin filaments are present.

B) They are the regions where actin (thin) and myosin (thick) filaments overlap.

The A band contains zones ____ and _____ line

H Zone and M Line

The A band appears _____ when viewed under a microscope

Darkn

During muscle contraction, what happens to the A bands in skeletal muscle fibers?

A) They shorten in length.

B) They become more distinct and visible.

C) They remain the same length.

D) They disappear completely.

C) They remain the same length.

What is the H zone in a skeletal muscle fiber?

A) The area where actin filaments overlap

B) The region where myosin filaments are not overlapping with actin

C) The zone that contains the Z discs

D) The region where the sarcoplasmic reticulum is located

B) The region where myosin filaments are not overlapping with actin

What happens to the H zone during muscle contraction?

A) It becomes wider as actin filaments move closer together

B) It remains the same size regardless of contraction

C) It disappears completely during contraction

D) It becomes narrower as actin filaments slide over myosin filaments; zone dissappears during maximal muscle shortening

D) It becomes narrower as actin filaments slide over myosin filaments; zone dissappears during maximal muscle shortening

The ____ line is located in the middle of the H zone and serves as an attachment site for thick filaments

M Line

What is the function of the M line in skeletal muscle fibers?

A) It anchors the actin filaments during muscle contraction.

B) It connects the sarcomere to the muscle fiber membrane.

C) It helps maintain the alignment of thick filaments (myosin) in the center of the sarcomere.

D) It serves as the site for calcium ion storage during contraction.

C) It helps maintain the alignment of thick filaments (myosin) in the center of the sarcomere.

________ have a striped appearance and are visible when viewing the longitudinal section of the skeletal muscle tissue

Striations

________ is a :

- spiral-like structure

- extends from Z discs to the M line through the core of each thick filament

- Function: stabilizes the portion of the thick filament and maintains the alignment in a sacromere

Connectin

What is the role of dystrophin in skeletal muscle fibers?

A) It helps generate electrical impulses for muscle contraction.

B) It anchors actin filaments to the muscle cell membrane, maintaining structural integrity.

C) It facilitates the storage of calcium ions during muscle contraction.

D) It regulates the release of energy stored in the muscle fibers.

B) It anchors actin filaments to the muscle cell membrane, maintaining structural integrity.

If you have abnormal dystrophin, it may cause _____ ______

Muscle Dystrophy

What is the primary role of mitochondria in skeletal muscle fibers?

A) To store calcium ions for muscle contraction

B) To produce ATP through cellular respiration, providing energy for muscle contraction

C) To protect muscle fibers from oxidative damage

D) To transmit electrical signals for muscle coordination

B) To produce ATP through cellular respiration, providing energy for muscle contraction

Why do skeletal muscle fibers contain a high number of mitochondria?

A) To increase muscle fiber size for strength

B) To allow for rapid oxygen consumption during intense physical activity

C) To facilitate the breakdown of muscle proteins

D) To store excess calcium needed for contraction

B) To allow for rapid oxygen consumption during intense physical activity

_______ binds oxygen inside a muscle and ______ binds oxygen inside the blood

Myoglobin; Hemoglobin

How does myoglobin differ from hemoglobin in its role within muscle tissue?

A) Myoglobin carries oxygen, while hemoglobin stores glucose in muscle cells.

B) Myoglobin is found in muscle fibers, while hemoglobin is found in red blood cells.

C) Myoglobin transports carbon dioxide, while hemoglobin transports oxygen.

D) Myoglobin stores fat for energy, while hemoglobin is responsible for muscle contraction.

B) Myoglobin is found in muscle fibers, while hemoglobin is found in red blood cells.

How does creatine phosphate provide energy to skeletal muscle during short bursts of intense exercise?

A) It is converted into glucose for ATP production.

B) It donates a phosphate group to ADP, quickly regenerating ATP.

C) It directly stimulates the muscle fibers to contract.

D) It stores calcium ions, which are used for muscle contraction.

B) It donates a phosphate group to ADP, quickly regenerating ATP.

What is the role of creatine phosphate in skeletal muscle fibers?

A) It acts as an energy source to help muscles contract during high-intensity activity.

B) It helps in the transportation of oxygen to muscle cells.

C) It acts as a long-term energy storage molecule in muscle fibers.

D) It contributes to the generation of heat during muscle contraction.

A) It acts as an energy source to help muscles contract during high-intensity activity.

Creatine phosphate donates _____ to ____ to make _____

Phosphate; ADP; ATP

The _____ ____ _____ are nerve cells that transmit nerve signals from the brain and spinal cord to control skeletal muscle activity

Somatic Motor Neurons

What is the connection between a somatic motor neuron and a skeletal muscle fiber called?

Neuromuscular Junction