Muscles Pt 1

What do muscles make up in the body?

Nearly half of the body’s weight

Muscles functions include:

1.) Movement

2.) Stability

3.) Control of openings

4.) Heat production

5.) Glycemic control

The function of movement for muscle includes:

1.) Moving from place to place

2.) Moving body parts

3.) Moving body contents during breathing

4.) Circulation

4.) Digestion

5.) Speech

6.) Writing

7.) Facial expressions

8.) Non-verbal communications

The function of stability for muscle includes:

1.) Maintaining posture by preventing unwanted movements

2.) Anti-gravity muscles that help us from falling over

3.) Stabilizes joints by maintaining tension

The function “control of openings and passageways” for muscle includes:

1.) Sphincters: internal muscular rings that control the movement of food, blood, and other materials within the body.

The function “heat production” for muscle includes:

Skeletal Muscles that are 85% of our body heat

The function “Glycemic Control” for muscle includes:

The concept that muscles absorb and store glucose which helps regulate blood sugar concentration within the normal range.

How many human skeletal muscles are there?

600

What are the three kinds of muscle tissue?

1.) Skeletal

2.) Cardiac

3.) smooth

What is a muscle’s specialized major purpose?

Convert chemical energy in ATP into the mechanical energy of motion (ATP —> Motion)

What is myology?

The study of the muscular system

What is muscle fiber?

The basic cellular unit of muscle

What are the characteristics of a muscle fiber?

1.) Long, multinucleate cell (contains multiple nuclei)

2.) The cytoplasm(material inside cell) is called sarcoplasm

3.) The sarcoplasm(material inside muscle fiber) contains nuclei, mitochondria, filaments, and specialized membranous structures

What are the four functional characteristics of muscle?

1.) Excitability (Irritability)

2.) Contractility

3.) Extensibility

4.) Elasticity

Excitability (irritability) is the ability to do what?

Ability to receive and respond to stimulus with membrane depolarization

Contractility is the ability to do what?

Ability to shorten forcibly when properly stimulated

Extensibility is the ability to do what?

Ability to be stretched or extended

Elasticity is the ability to do what?

Ability of muscles fibers to resume its resting length after being stretched

What do skeletal muscles attach to and cover?

the skeleton

Is skeletal muscle involuntary or voluntary?

Voluntary somatic nervous system

Two characteristics of skeletal muscle

1.) Striated

2.) multinucleate

Cardiac Muscles are the walls of the _______.

Heart

Are cardiac muscles involuntary or voluntary?

Involuntary autonomic nervous system that has continuous contractility

Two characteristics of Cardiac muscle

1.) striated

2.)uninucleate

Smooth muscles are walls of _____________.

Hallow, visceral organs.

Are smooth muscles involuntary or voluntary?

Involuntary autonomic nervous system

Two characteristics of smooth muscle.

1.) Non-striated

2.) uni-nucleated

Epimysium

connective tissue sheath that muscles are covered by

Bundles of muscle fibers are called…

Fascicles

What are fascicles covered by?

Fibrous sheath called perimysium

What is endomysium

fine sheath of connective tissue reticular fibers thats covers each single muscle fiber

what is the plasma membrane of a fiber called

sarcolemma

Around individual fibers =

endomysium

around fascicles =

perimysium

around the entire muscle =

epimysium

What is the hierarchy of organization of muscle tissues:

Muscle - gross level

Fascicle - Tissue

Myofiber - Cell

Myofibrils - Fibrous organelles

Sarcomeres - Part of a myofibril

Myofilament - part of a sarcomere

Myosin and Actin - molecules that make up myofilaments

What is the structure of myofibril

made of a basic repeating unit that is called a sarcomere.

Also contain Contractile proteins ( actin and myosin ), elastic protein (titin), and regulatory proteins (tropomyosin,troponin)

Sarcomeres have _______.

Striations

What is a single muscle cell ( myofiber) composed of?

Many sarcomeres in series

A sarcomere is from what to what

Z disk - Z disk

This represents what

Myofiber

This represents what

a myofibril

This represents what

A myofilaments

Myosin are ( ______) filaments

thick

How are myosin thick filaments formed

from myosin tail (body of filament) and head (links to actin)

What are thin filaments made of

the proteins: Actin, tropomyosin and troponin

How do muscles contract?

1.) Each sarcomere in a myofibril shortens

2.) The entire myofibril shortens

3.) Ca²+ release from the sarcoplasmic reticulum controls shortening

What does shortening of an individual sarcomeres lead to…

shortening of a single muscle cell (myofiber)

What does each sarcomere in a myofilament shorten for?

to produce an overall shortening of a muscle fiber

What are the elements that control shortening?

Mitochondria ( for ATP production )

T - Tubules ( internal extensions of the sarcolemma )

Sarcoplasmic reticulum ( Ca²+ storage )

How is Ca²+ apart of muscle fiber contraction

it controls it.

Nerves control Ca²+ and do what?

releases Ca²+ from the SR to trigger contraction

What system is in a Sarcomere?

The T-Tubule (Transverse Tubule)

What do narrow t-tubules permit?

the conduction of electrical impulses from the sarcolemma deep into the muscle near the sarcoplasmic reticulum

Sarcoplasmic reticulum

regulates intracellular levels of calcium by releasing it in a way controlled by electrical impulses from the T-tubule

What is terminal cisternae

when enlarged SR connects to the T-Tubule

What makes a triad?

Two terminal cisternae and one t-tubule, making it a “threesome” of membranes

What makes cross bridges?

myofilaments

myosin is a

thick filament

The head of a myosin..

forms cross bridges with actin

the tail of myosin..

forms the thick filament

Actin is a

Thin filament

F-Actin forms..

the backbone of the thin filament

what is it called when a myosin head binds to an active actin filament

crossbridge formation

Tropomyosin

controls actin-myosin cross-bridge formation by blocking myosin from making a cross bridge

Cross bridges generate what?

Isokinetic Force

What is troponin

it controls tropomyosin

Ca²+ controls what

troponin

What happens when Ca²+ is released from SR

Undoes cross bridge

What do electrical impulses do

control the release of calcium from the SR

What does calcium regulate

muscle contraction

Where is Atp from

mitochondria

What does the ATP from mitochondria provide?

Chemical energy to myosin so that its head can bend

When atp from mitochondria provides chemical energy to myosin what does that generate?

Kinetic moving force