Muscular System

Define origin

the point of muscle attachment that normally does NOT move

Define insertion

the point of muscle attachment that normally DOES move

Agonist

considered to be main muscle that performs particular action (primary mover)

Synergist

assist the agonist (primary mover)

Fixator

a muscle that stabilizes a joint. Allows movement to actually take place.

Antagonist

muscle that does opposite action of the agonist

If you want the movement to occur, the antagonist needs to be _____?

relaxed

Muscles can only perform this one action

Contract/contraction

Sarcolemma and function

plasma membrane of a muscle.

function: it separates the intracellular and extracellular spaces of the muscle fiber.

Which organelle is the first to receive an electrical impulse?

sarcolemma

What are the gaps filling the sarcolemma called?

transverse tubules

Transverse tubules and function?

found as spaces along sarcolemma and they function to send an electrical signal into deeper portions of the muscle fiber.

What sends the electrical impulse to our muscle fiber?

motor neuron

Motor neuron and function

the electrical impulse comes from these and they function to send electrical impulses from nervous system over towards what we call effectors (like muscles). The electrical impulse will spread along the sarcolemma, utilizing the t-tubules to have them go deeper into muscle fiber.

Nucleus of muscle fiber quality

it is multi nuclear

What releases and stores calcium to our muscle fiber?

sarcoplasmic reticulum

Sarcoplasmic reticulum and function

this will be the muscle fiber’s version of the smooth endoplasmic reticulum. It stores and releases calcium, and surrounds the t-tubules.

What filaments are responsible for muscle contractions?

actin and myosin

What protein stabilizes actin filament?

dystrophin

When we start from one dystrophin and end at another, what do we call that unit?

sarcomere

Muscle movements need ___

calcium

Motor nueron

send signals from nervous system to the muscle fiber

_____ is going to be needed in order for ____ protein to attach to ____.

Calcium , myosin , actin

Why do we need calcium?

we use it to move the protein blocker so that myosin can bind with actin protein.

Electrical impulse using _____ activates the sarcoplasmic reticulum to release _____.

transverse tubules, calcium

Epimysium is made up of _____.

dense regular connective tissue

_____ forms the tendons and is continuous with tendons.

epimysium

Muscle fascia is made up of ______.

dense connective tissue

_____ surrounds the epimysium and holds the muscle in place.

muscle fascia

Perimysium is made up of _______ tissue.

dense fibrous connective

Perimysium and what are it’s core functions?

• is a sheath of connective tissue that groups individual muscle fibers into bundles called fascicles.

• functions:

  • structural support

  • force transmission

  • pathways for nutrients

  • elasticity

Perimysium is primarily composed of ___ and ___ fibers.

collagen and elastin

The _____ is the outermost layer of dense, fibrous connective tissue that wraps around an entire skeletal muscle.

epimysium

Endomysium

the inner most layer of delicate connective tissue that wraps around each individual muscle fiber.

Endomysium is made up of _____ CT.

areolar

Types of fascicle arrangements

• parallel

• pennate

• convergent

• circular

What is a motor unit defined by?

one motor neuron and all of the muscle fibers it communicates with. Works by recruiting one motor neuron with more motor neurons.

Hypertrophy

• needs exercise to occur

• Muscle fiber becomes thicker

• damage to muscle fibers when you exercise. The tear signals surrounding tissues and cells in for repair. Also signals more myofibrils.

• if you do a particular exercise repeatedly the muscle will take on a particular shape

Atrophy

• tends to be a rapid process

• the wasting away, thinning, or decrease in size of a body tissue or organ.

• the loss of muscle mass

• Muscle fiber becomes thinner

• the lack of nutrition, decrease in physical activity or a disruption in the nerve signals keeping tissue active

What repairs muscle tears?

satellite cells

Which is the weakest fascicle arrangement?

non-fusiform parallel arrangement

Which is the strongest fascicle arrangemement?

multipennate fascicle

tendon in the middle with one fascicle makes a?

unipennate

tendon with two fascicles makes a?

bipennate

two types of parallel arrangements?

non-fusiform and fusiform

Tendon is made up of this type of tissue

dense regular connective tissue

Both the epimysium and the tendon are made up of this type of tissue

dense regular connective tissue

List the qualities of smooth muscle

• found around almost all internal organs

• Actin and myosin are present but not organized

• Doesn’t make forceful contractions but doesn’t fatigue

• Involuntary contraction

  • Nerves, hormones, change in environment

List the qualities of skeletal muscle

• striated appearance

• Forceful contractions, fatigues easily

• Voluntary contraction

  • Neuromuscular junction

List the qualities of cardiac muscle

• actin and myosin organized (striated appearance)

• Intercalated disks between cells

• Contraction strength and endurance intermediate

• Involuntary contraction

  • Controlled by intrinsic conduction system