Muscular system

BIO 1

In general, oxygen debt develops as a result of ______

strenuous exercise

define muscle tone

state of partial contraction of muscles while at rest

in what types of muscle are the myofilaments arranged into sarcomeres?

cardiac muscle and skeletal muscle

Label

frontalis

Label

temporalis

Label

Orbicularis Oris

Label

Sternocleidomastoid

Label

biceps brachii

Label

Brachialis

Label

deltoid

Label

Brachioradialis

label

Occipitalis

label

deltoid

label

triceps brachii

label

Biceps femoris

label

semitendinous

Label

Gastrocnemius

soleus

label

Gluteus Maximus

Label

Guteus medius

label

infraspinatus

Label

Latissimus dorsi

label

Rhomboid

label

trapezius

Label

zygomaticus

label

masseter

label

sternocleidomastoid

label

orbicularis oris

label

buccinator

label

platysma

Muscle contractions that generate less force than the resistance and result in lengthening of the muscle are called ___ contractions

eccentric contractions

which muscle is the prime mover of the shoulder abduction (abduction of the arm)?

deltoid

what word segment means “muscle”?

myo-

name the organelles that store neurotransmitter molecules within the distal end of a motor neuron axon

synaptic vesicles

what generates the force that shortens the sacromeres to bring about muscle contraction

Myosin cross-bridges pulling on the actin filaments

at neuromuscular junctions, acetylcholine binds to__

receptors in the muscle fiber membrane

when a muscle fiber stimulated at a high enough frequency that it doesn’t have time to relax, the forces of the individual twitches combine to cause stronger contractions. what is this process called?

summation

what is the name between a motor neuron and a muscle fiber at the neuromuscular junction?

synaptic cleft

muscles with attachment points on the pelvis girdle and on the femur will cause what type of movement?

movement of the thigh

when describing the roles of muscles involved in a movement, what is the role of the antagonist?

to oppose the action

Thin filaments

Actin

Troponin

Tropomyosin

Thick filaments

Myosin

What type of chemical is released by neurons? These chemicals then bind to effector cells.

Neurotransmitters

the _____ are repeating units within muscle fibers that act as the functional units of muscle contraction

sarcomeres

Within myofibrils, the area between two successive Z lines is called a(n)

sarcomere

A neuromuscular junction is a synapse between Blank______ and Blank______.

a motor neuron; a muscle fiber

What are the three types of muscles found in the human body?

• Skeletal

• Cardiac

• Smooth

What is the name of the space between a motor neuron and a muscle fiber at the neuromuscular junction?

Synaptic cleft

Due to their shape, muscle cells are also called muscle ____

fibers

When is lactic acid produced?

During anaerobic metabolism

In order to communicate with a target cell at a synapse, a neuron releases chemicals called

neurotransmitters

Prolonged or intense exercise can lead to a condition called muscle ___

, defined as the loss of a muscle's ability to contract.

muscle fatigue

How many myofibrils and sarcomeres are found in a muscle fiber?

Each muscle fiber contains many myofibrils, each made of many sarcomeres joined end to end.

Muscle contractions generate ______, which is important for the overall functioning of the body.

heat

A skeletal muscle will typically only contract when stimulated by its motor neuron at the

neuromuscular junction

For a typical muscle fiber in its optimal state, how many action potentials generated by a motor neuron must arrive at the neuromuscular junction to reach the threshold stimulus?

Typically, a single action potential is enough to bring the muscle fiber to the threshold.

The synaptic ____ is the gap between a motor neuron and the muscle fiber at a neuromuscular junction.

cleft

When the frequency of stimulation of a muscle fiber increases, eventually the individual twitches combine by the process of ___ which results in a sustained contraction.

summation

During high-intensity exercise, anaerobic metabolism results in the production of pyruvic acid, which is then converted to ____ acid.

lactic acid

Muscle fatigue is a condition described by ____ and is usually caused by prolonged use of a muscle.

the loss of a muscle's ability to contract

A motor neuron and the muscle fibers that it controls constitute a motor ___

unit

true or false - Muscles generate heat when they contract.

true

What type of contraction involves the development of tension but no change in length?

Isometric

If a muscle fiber is subjected to stronger and stronger electrical impulses, it will initially be unresponsive until a strong enough impulse is applied which causes it to contract. The level of electrical stimulation needed to stimulate contraction is called the

threshold stimulus

The cells of ____muscle are tapered, lack striations, and have a sarcoplasmic reticulum that is not very extensive.

smooth

Why does summation result in an increased force of contraction?

Individual twitches combine due to the high frequency of stimulation.

The product of glycolysis, pyruvic acid, is converted to ______ when oxygen is not available.

lactic acid

What is the name of the structures that connect cardiac muscle cells end-to-end, allowing muscle impulses to pass freely from one cell to another?

Intercalated disc

What is a motor unit composed of?

A single motor neuron

Several muscle fibers

What structures within cardiac muscle tissue allow the entire cardiac muscle network to contract in unison?

Intercalated discs

A muscle that is generating increased tension without changing its length is undergoing a(n) ____ conttraction

isometric

The end of a muscle that is fixed (relatively immovable) is called its

origin

characteristics of smooth muscle cells.

They are not striated.

Their sarcoplasmic reticula are not well developed.

They have a single nucleus.

When describing the roles of muscles in an action, what is the role of the agonist?

To cause an action

When the frequency of stimulation of a muscle fiber increases, eventually the individual twitches combine by the process of _____which results in a sustained contraction.

summation

Cardiac muscle cells are connected by cross-bands that include components of desmosomes and gap junctions. These cross-bands are called

intercalated discs.

Muscles can act in different ways during a particular movement. What is the role of the antagonist?

To oppose the action

Structures called _____ allow action potentials to pass rapidly between cardiac cells, causing the entire cardiac muscle to contract in unison.

intercalated discs

What is the term for muscles that assist a prime mover to cause movement?

Synergists

The point of attachment for a muscle that remains relatively stationary is its

origin

Label letter A

Epicranial aponeurosis

Label B

frontalis

Label C

Occipitalis

Label D

Temporalis

A muscle that functions to cause action is referred to as the

agonist

What is the action of the masseter?

It elevates mandible.

When a muscle fiber is stimulated at a high enough frequency that it doesn't have time to relax, the forces of the individual twitches combine. What is this process called?

Summation

The latissimus dorsi muscle is indicated by the letter

C

A muscle that opposes the action at a joint is classified as a(n)

antagonist

Which muscle of the anterior surface of the arm is indicated by the arrow?

Deltoid

Any muscle that assists the agonist during a movement is called a(n)

synergist

Muscles found on the______ surface of the humerus cause flexion of the forearm at the elbow.

anterior

what is A

Masseter

what is B

Orbicularis oculi

what is C

Orbicularis oris

what is D

Platysma

what is E

Sternocleidomastoid

The gluteus maximus is indicated by the letter ___

. The gluteus medius is indicated by the letter

___

B & A

Which muscle elevates the mandible?

Masseter

Muscles of the ______ muscle group flex the knee and those of the ______ muscle group extend the knee.

hamstrings; quadriceps femoris