Muscular System

Skeletal muscles can stretch up to three times their contracted length, this is called __________.

Extensibility

Stretching a muscle and increasing sarcomere length belongs to what universal muscle characteristic?

Extensibility

T/F: In response to an action potential entering the neuron, calcium ions diffuse from the sarcolemma into the sarcoplasm.

False

T/F: The binding of ATP immediately initiates the sliding of muscle filaments past one another.

False

True or False: A muscle described as having a direct attachment is attached to the bone via a tendon or aponeurosis.

False

True or false: Muscles acting as antagonists produce most of the force during a particular joint action

False

T/F: An action potential introduced at the neuromuscular junction is propagated along the sarcoplasmic reticulum.

False.

On its outer surface, the epimysium is continuous with which of the following Perimysium Sarcolemma Endomysium Fascia

Fascia

Which term refers to a sheet of connective tissue that separates neighboring muscles or muscle groups? Perimysium Fascia Epimysium Endomysium

Fascia

Which term refers to bundles of muscle fibers, wrapped in connective tissue, within a muscle? Compartments Striations Fascicles Tendons

Fascicles

Since muscle contraction requires energy to do work, muscles help maintain our body _______.

heat

Sodium ion channels close, but __________ channels remain open, and loss of that ion ______ the membrane.

Potassium ion; repolarizes

Somatic efferents release neurotransmitters into the synaptic cleft, which elicits a _______ from the muscle tissue.

response

A ________ filament consists of 200-500 myosin molecules bundled together, with the heads projecting outward in a helical array.

thick

Also known as responsiveness, __________ is a characteristic of all cells, but more highly developed in muscle and nerve cells.

excitability

Nearing 60 degrees of elbow flexion, the antagonistic triceps brachii continues to demonstrated the characteristic of _________.

extensibility

A muscle that holds a bone steady during an action is called a ______.

fixator

A region of overlap between the thin and thick myofilaments exists, and between each is a _______ zone.

bare

A muscle with its fasciculi arranged like barbs of a feather is called a _______ muscle.

bipennate

Muscle contractions are initiated by the binding of _______ to ______.

calcium ions; troponin

Using ______, or valves, muscles control the passage of contents from one body cavity or lumen to another.

sphincters

Muscles also function in ________ by preventing unwanted movement, as in maintaining posture.

stability

A muscle cell is ____________ by a neurotransmitter from a motor neuron.

stimulated

An action potential enters the depths of a muscle fiber by way of ________.

the T tubules

What is a retinaculum?

A band of connective tissue that covers and stabilizes a group of tendons

Which describes the endomysium? A connective tissue sheath surrounding an entire muscle. The plasma membrane of an individual muscle cell. A loose connective tissue layer around each individual muscle cell. A connective tissue sheath bundling many muscle fibers into fascicle

A loose connective tissue layer around each individual muscle cell.

The bond between the active site on actin and the myosin head is broken when an ______.

ATP molecule binds to the myosin head.

The bond between the active site on actin and the myosin head is broken when an _______.

ATP molecule binds to the myosin head.

Which term is another word for prime mover?

Agonist

Functions of Connective tissue

Aids in elastic recoil of muscle, prevents muscle from overstretching, helps muscle function more efficiently, surrounds muscle fascicle, binding them together.

Which term refers to a muscle that opposes the prime mover?

Antagonist

How would you classify the muscle shown here?

Circular

Action potentials in the center of the fiber radiating to the ends and depolarization of a single muscle fiber causing depolarization of adjacent muscle fibers belongs to what universal muscle characteristic?

Conductivity

Creation of force, pulling two bones together, and actively resisting the separation of two bones belongs to what universal muscle characteristic?

Contractability

Muscles can pull bones closer to one another and increase the motility of some organs. This is due to the property of ___________.

Contractility

Placing muscle in a solution containing Calcium and ATP belongs to what universal muscle characteristic?

Excitability

A stretched muscle returning to its original length and passively resisting the separation of two bones belong to what universal muscle characteristic?

Elasticity

Increasing the flexion angle of the elbow, the elbow extensors exhibit _________ while the flexors eccentrically contract.

Elasticity

Muscles can stretch, and when released, return to their original, shorter length. This property is referred to as ________.

Elasticity

when an ion channel opens in a sarcolemma, ions flow across the membrane altering the potential. These cells are said to be ____________.

Electrically excitable

Which provides extracellular environment for muscle fiber and associated nerve ending? Perimysium Epimysium Fascia Endomysium

Endomysium

What term refers to a muscle that prevents a bone from moving during an action?

Fixator

What are muscle compartments?

Functional groups of muscles surrounded by fascia

A muscle that is thick in the middle and tapered at each end is classified as a ______ muscle.

Fusiform

By absorbing a large share of one's ______, muscles play an important role in blood sugar control.

Glucose

Which are functions of skeletal muscles? Heat production Movement Blood sugar regulation Formation of new blood cells

Heat Production; Movement; Blood sugar regulation

Muscles that are entirely contained within a particular region are called ______ muscles.

Intrinsic

Pausing at the top while a drink is taken, ______ contractions are seen in the elbow flexors.

Isometric

Which of the following best describes the role of CA2+ in muscle contraction? It binds to tropomyosin, moving troponin, so that myosin heads can bind to actin It binds to tropomyosin, moving troponin, so that actin heads can bind to myosin It binds to troponin, moving tropomyosin, so that myosin heads can bind to actin

It binds to troponin, moving tropomyosin, so that myosin heads can bind to actin.

The difference in charge created by ECF ions and the ICF ions is called the ______________.

Membrane potential

Membrane potential is measured in _________.

Millivolts

The endomysium is a connective tissue sheath that wraps around which of the following: Group of muscles Entire Muscle Muscle Fiber muscle fascicle

Muscle fiber

A single __________ molecule consists of two intertwined polypeptides, forming a twisted, filamentous tail and a double globular head.

Myosin

Which of the following is the site of ATP binding and hydrolysis?

Myosin

During muscle contractions, cross-bridges form between the _______ and the ________.

Myosin heads; actin filaments

Which of the following happens as actin and myosin filaments slide past each other during muscle contraction? Actin filaments shorten, while myosin filaments do not. Myosin filaments shorten, while actin filaments do not. Either actin or myosin filaments shorten, but not both at the same time. Neither actin nor myosin filaments shorten

Neither actin nor myosin filaments shorten

Are the following functions of connective tissue? Carries electrical impulse for a muscle cell Striations allow for muscle contraction Contracts the muscle, making it shorter Stores glucose to provide energy to muscle cell

No

A muscle of uniform width with fascicles aligned along its longitudinal axis would be classified as a ________ muscle.

Parallel

Stretch receptors called muscle spindles are located within which connective tissue layer? Epimysium Endomysium Perimysium

Perimysium

Which term refers to loose connective tissue layer that surrounds muscle fascicles? Endomysium Perimysium Fascia Epimysium

Perimysium

A cell membrane is __________ when there is a higher concentration of cations on one side, and a higher concentration of __________ on the other.

Polarized; anions

During a particular action, an antagonist may do which of the following? Select all that apply Holds the bone (to which it is attached) steady during the action. Generates most of the force needed to produce the action. Relaxes to allow other muscles to have control over the action. Limits the speed or range of the action by opposing the other muscles involved

Relaxes to allow other muscles to have control over the action; limits the speed or range of the action by opposing the other muscles involved.

The specific name for a muscle fiber's plasma membrane is the __________.

Sarcolemma

Terminal cisternae are a structural feature of the organelle called the _________________.

Sarcoplamic reticulum.

Which term refers to a muscle that does not produce most of the force but instead works together with other muscles to help cause a movement?

Synergist

In a muscle fiber the _______ is adjacent to the terminal cisternae so the action potential can stimulate calcium ion channels.

T Tubule

The structures indicated by the arrows are examples of which of the following? Tendons Retinacula Fasciae Ligaments

Tendons

Which is an example of an aponeurosis? The feather-like structure of the rectus femoris. The broad, sheet-like tendon located beneath the scalp. The thick sheet of connective tissue that separates the lateral and posterior compartments of the arm. The fibrous joint formed by a tooth in its socket.

The broad, sheet-like tendon located beneath the scalp

Which structure do the calcium ions bind to when muscle contraction is initiated?

The troponin molecule

Which of the following statements about the "heads" of the myosin molecules is true? They form permanent links with actin filaments They can attach to different sites on the actin filament. They straighten the myosin filaments.

They can attach to different sites on the actin filament.

What are intermuscular septa?

Thick fasciae that separate muscles into compartments

The __________ is described as two strands of actin molecules wrapped together.

Thin filament

How would you classify this muscle based on its fascicle orientation?

Triangular

Which of the following is not a filamentous protein? Actin Mysoin Troponin Tropomyosin

Troponin

During contraction of a muscle, calcium ions bind to the ______.

Troponin molecule

T/F: After cross-bridges form, phosphate is released, followed by ADP.

True

T/F: An action potential causes depolarization of the T tubule membrane.

True

T/F: Each myosin protein has a globular head that extends outward from the myosin filament.

True

T/F: T tubules are invaginations of the sarcolemma of a muscle cell

True

T/F: T tubules are invaginations of the sarcolemma of a muscle cell.

True

T/F: The sequence of cross-bridge formation and myofilament movement will be repeated as long as calcium ions and ATP are present.

True

T/F: Unflexing of the myosin head requires ATP.

True

T/F: When cross-bridges form, and the muscle fibers contract, the actin myofilament slides past the myosin myofilament.

True

Match description with correct type of pennate muscle shape: Unipennate, Bipennate, Multipennate Fascicles insert on the tendon from both sides; Many bipennate muscle units merging onto one tendon; all fascicles approach tendon from one side of muscle

Unipennate-all fascicles approach tendon from one side of the muscle Bipennate-fascicles insert on the tendon from both sides Multipennate-many bipennate muscle units merging onto one tendon

Cross-bridges form between the __________ and the ________.

actin filaments; myosin heads

The process just described is called a(n) ____________.

action potential

The pump mechanism that maintains the resting membrane potential is an example of _________.

active transport

The bicep brachii and brachialis begin to flex the elbow with greater force than the elbow extensors resulting in a(n) _________ contraction.

concentric

The ability to carry an electrical charge along the cell is called ___________.

conductivity

The membrane ______, or becomes less negative.

depolarizes

The connective tissue that surrounds each muscle fiber is called the ____________.

endomysium

Connective tissue layer that covers the entire muscle is called the _________.

epimysium

Muscles function in __________ of the head, neck, and limbs, as well as propulsion of the contents through the digestive tract.

movement

The perimysium is a connective tissue sheath that surrounds which of the following: Individual muscle fibers muscle fascicles the entire muscle groups of muscles

muscle fascicles

Each myofibril is made of up to several __________.

myofilaments

The connective tissue layer that wraps fascicles is called the _______.

perimysium

An action potential causes calcium ions to diffuse from the ________ into the ____________.

sarcoplasmic reticulum; sarcoplasm

Ion channels open in the plasma membrane and _____ diffuse into the ________.

sodium ions; ICF

A thin filament consists of two intertwined chains of G actin molecules, smaller filamentous ________ molecules, and troponin.

tropomyosin