a&p 1 - muscle physiology

Type of muscle fiber builds ATP using the electron transport chain and contracts slowly

Slow oxidative

What step comes 1st in the cross bridge cycle

Cross-bridge formation

What step comes 2nd in the cross bridge cycle

Power stroke

What step comes 3rd in the cross bridge cycle

Cross-bridge detachment

What step comes 4th in the cross bridge cycle

Cocking the myosin head

The overload principle in muscle training is defined as:

Gradually increasing the resistance or intensity of exercise to stimulate muscle growth and strength

During muscle contraction, the entire muscle fiber shortens by:

shortening the myofibrils

What happens during the power stroke

actin is pulled toward the midline

What happens during the cross bridge formation

myosin attaches to actin

What happens during the cocking of the myosin head

myosin stands up

What happens during the cross bridge detachment

myosin lets go of actin

How do neurons at the neuromuscular junction stimulate contraction?

By generating an action potential in the muscle through the release of acetylcholine.

How does tropomyosin function to regulate muscle contraction?

By blocking the myosin-binding sites on actin.

Which type of muscle fiber builds ATP using glycogen and contracts quickly?

Fast glycolytic

Which chemical signal is responsible for repolarizing the membrane in an action potential?

Potassium

Skeletal muscle fibers are stronger in males than females.

False

The first chemical signal for muscle contraction at the neuromuscular junction is:

Acetylcholine

Which chemical signal is responsible for depolarizing the membrane in action potentials?

Sodium

Which type of muscle fiber would be used for holding poses in yoga?

Slow oxidative

What happens during the period of contraction?

Cross bridge is actively form and creating tension

What happens during the latent period?

Excitation-contraction coupling first begins

What happens during the period of relaxation

Calcium is pumped back into sarcoplasmic reticulum

Where would you find cardiac muscle tissue?

In the heart

Where would you find smooth muscle tissue?

Hollow organs and blood vessels

Where would you find skeletal muscle tissue?

Attached to bones

Each muscle fiber requires its own neuron for contraction.

False

Which type of muscle contractions generate force as the muscle shortens?

Concentric

An action potential is defined as:

A temporary reversal of membrane potential that propagates along the membrane of a neuron.

Which of the following is not an effect of resistance (weight training) exercise on muscles?

Increased amount of myoglobin

Which part of a skeletal muscle fiber functions to store calcium?

sarcoplasmic reticulum (SR)

1st step of muscle contraction

action potential initiation

2nd step of muscle contraction

A neuron releases acetylcholine (ACh)

3rd step of muscle contraction

Chemically-gated sodium (Na⁺) channels open

4th step of muscle contraction

The membrane of a muscle fiber depolarize

5th step of muscle contraction

The calcium (Ca²⁺) channels/doors are pushed open

6th step of muscle contraction

Calcium binds to troponin

7th step of muscle contraction

Tropomyosin unblocks the myosin-binding sites on actin

8th step of muscle contraction

Myosin attaches to actin

Smooth muscle functions

Move food, regulate blood pressure, regulate organ function, and more.

Skeletal muscle function

move skeleton

Cardiac muscle functions

pump blood

How does troponin function to regulate muscle contraction?

By retaining/holding calcium.

Sarcoplasm

muscle fiber cytoplasm

Sarcoplasmic reticulum (SR)

muscle fiber smooth endoplasmic reticulum

Sarcolemma

muscle fiber plasma membrane

T tubule

muscle fiber junction with sarcolemma

endomysium

Individual muscle cells are wrapped in a layer of connective tissue

fascicles

groups of muscle fibers/cells

epimysium

skeletal muscles (made up of many fascicles) are wrapped in

A motor unit is defined as:

A motor neuron and all the muscle fibers it innervates.

Which part of a skeletal muscle fiber functions to bring action potentials to the sarcoplasm?

T tubules

Order the parts of a muscle from smallest to largest.

fibers → fascicles → muscles

The age-related loss of muscle mass, strength, and function is known as:

sarcopenia

What is the role of calcium in regulating muscle contraction?

It causes a shift in the troponin-tropomyosin complex, exposing the myosin-binding sites.

Which if the following is NOT involved in muscle relaxation?

Myosin attaches to actin.

The adductor muscles of the thigh are named based on their action.

True

Which of the following best describes convergent fascicle arrangement?

come to a single common attachment point

When the epimysium of skeletal muscles attaches to the bone this is considered a direct attachment.

True

Which of the following muscles is circular in shape?

orbicularis oris

The transverse abdominis is named after the                             of its muscle fibers.

direction

Which of the following best describes parallel fascicle arrangement?

arranged in the same direction as the long axis of the muscle

Groups of skeletal muscle cells that contract together are called                                 .

fascicles

-mastoid

mastoid process of temporal bone

sterno-

breastbone

cleido-

collar bone

Which of the following is true of indirect attachments of skeletal muscles?

the epimysium forms a tendon or aponeurosis that attaches to the bone

The frontalis muscle is named based on its                        .

location

Which of the following best describes the gluteus maximus muscle in terms of naming?

large

How many origins does the biceps brachii have?

2

Agonists and antagonists are reversed for opposing actions.

True

Which of the following best describes circular fascicle arrangement?

arranged as concentric bundles

Which of the following types of muscles contribute most to an action?

agonists

what is convergent arrangement?

come to a single common attachment point

example of convergent arrangement

pectoralis major

what is parallel arrangement?

arranged in the same direction as the long axis of the muscle

example of parallel arrangement

biceps brachii

what is circular arrangement?

arranged as concentric bundles; sphincters

example of circular arrangement

orbicular oris

what is unipennate arrangement?

located on one side of the tendon

example of unipennate arrangement

extensor digitorum

what is bipennate arrangement?

located on both sides of the tendon

exampe of bipennate arrangement

rectus femoris

what is multipenate arrangement?

central tendon with branches of angled fascicles

example of multipennate arrangement

deltoid

how many skeletal muscle in the human body

650

examples of muscles named based of location

frontalis; intercostal muscles

examples of muscles named based of shape

deltoid; orbicularis oculi & orbicularis oris

examples of muscles named based of size

adductor longus (long) v adductor bevis (short); gluteus maximus v gluteus minimus

examples of muscles named based of direction

rectus (upright) abdominis; transverse (across a horizontal plane); external oblique (neither parallel nor perpendicular)

examples of muscles named based of action

adductor muscles of thigh; forearm flexors and extensors

examples of muscles named based of locations of their attachments

sternocleidomastoid

examples of muscles named based of numbers of origins

biceps and triceps brachii

what is an origin?

immovable attachment sites (usually proximal)

what is an insertion?

moveable attachment sites (usually distal)

agonists (prime movers)

muscles that contribute most to a muscle action

synergist

support agonists by providing extra force or by stabilizing the origin of an agonists

antagonists

muscles that oppose/ do the opposite of the agonist

flexion of forearm

agonist = biceps

antagonist = triceps

extension of forearms

agonist = triceps

antagonist = biceps

perimysium

fascicles are wrapped in