Chapter 9: Muscles

True

True or False: Nearly half of the body's mass is muscle

Skeletal, cardiac, and smoot

What are the three types of muscle

Skeletal muscle

Packaged into skeletal muscles: organs that are attached to bones and skin​

Skeletal muscle fibers

What are the longest fibers of all muscle and have striations

Cardiac muscle

Found only in the heart​

Smooth muscle

Found in the walls of hollow organs​

Excitability (responsiveness)

Ability to receive and respond to stimuli​

Contractility

Ability to shorten forcibly when stimulated​

Extensibility

Ability to be stretched ​

Elasticity

The ability to recoil to resting length​

White fibers

Fast glycolytic muscle fibers, make ATP through fermentation and burn ATP fast (fast twitch, type II)

Red fibers

Slow oxidative fibers that need oxygen (aerobic), small diameter, low in power (slow twitch, type I)

Motor endplate

Where do you find ligand gated Na+ channels on the muscle

Contract and generate forces

What is the purpose of muscles

True

True or False: Every Muscle is an oragan

Because they are a collection of many different tissues and many body systems working together for a specific bodily function

Why are muscles considered organs

Epimysium

What transfers movement from muscle to tendon, then to bone

Epimysium

What covers every muscle

Perimysium

What covers every fascicle

Endomysium

What covers every muscle fiber

True

True or False: Every single muscle fiber had the ability to put force on the tendon

Under the synaptic endbulb

Where do we find the motor endplate in a muscle

False

True or False: Motor units do not come in different sizes

Yes

Will a single motor unit be one fiber type

Insertion

Muscle attached to movable bone

Orgin

Muscle attached to immovable or less movable bone​

Direct (fleshy)

Muscle attachment where the epimysium is fused to the periosteum of bone or the perichondrium of cartilage​

Indirect

Muscle attachment where the connective tissue wrappings extend beyond the muscle as a rope-like tendon or sheet-like aponeurosis​

Sarcolemma

Muscle fiber plasma membrane

Sarcoplasm

Muscle fiber cytoplasm​

Glycosomes

What helps with glycogen storage in the muscle

Myoglobin

What is muscle helps with O2 storage

Motor unit recruitments

Maintaining joints and posture by recruiting other motor units so we don't fatigue, they also fine tune the force that muscles produce

Myofibrils

Densely packed, rodlike elements, a single muscle fiber can contain 1000s​, and it accounts for 80% of muscle cell volume

Striations

Stripes formed from a repeating series of dark and light bands along length of each myofibril​

A bands

Dark regions​ of the sarcomere that have all the myosin

H zone

Lighter region in the middle of a dark A band ​that houses exclusively thick filaments

M line

Line of proteins (myomesin) that bisects the H zone vertically, and support thick filaments ​

I bands

Lighter regions​ of sarcomere that have thin filaments with no overlap of thick filaments

Z disc (line)

Coin-shaped sheet of proteins on the midline of the light I band​, (act as scaffolding and aid in support)

Sarcomere

Smallest contractile unit (functional unit) of muscle fiber​

False

True or False: Fascicles can contain two types of muscle fibers

Sarcoplasmic reticulum

Stores calcium in muscle

Calsequestrin

What holds the stored calcium in the sarcoplasmic reticulum

Myofilaments

Orderly arrangement of actin and myosin within sarcomere​

Actin myofilaments

Thin filaments of the sarcomere

Myosin myofilaments

Thick filaments​ of the sarcomere

Myosin tail

Heavy chains of myosin intertwine to form what

Globular myosin head

Light chains of myosin form what

T tubules

Invaginations of the sarcolemma that aid in conduction of nerve impulses

Voltage gated Na+ and K+ channels

What kind of channels are found on the sarcolemma

Myofibrils

Thousands of sarcomeres linked together

Nebulin

Support the thin filaments

Titin

A large protein that is springy, elastic, extensible, and keeps thick filaments aligned laterally

Dystrophin

Transfers forces of muscle contraction to endomysium

Troponin

Calcium binding protein

Tropomyosin

Separates actin and myosin from one another

Positively

Are the heads of myosin positively or negatively charged

G actins

One chain of actins

F actins

Two chains of G actins

Thin filament

Multiple F actins

Calcium

What causes tropomyosin to not block actin from myosin

ATPase

What is found on the heads of myosin

Phase 1: ADP and P are on myosin, which carries a negative charge, which means it can't bind to the myosin binding site since it is negative; phosphate must go

Phase 2: Once the phosphate is gone, the myosin head connects to the myosin binding site of the actin, after that, it forms it shape, then gets rid of the ADP, which then results in a power stroke

Phase 3: Power stroke phase, multiple myosins are doing this to create a contraction

Phase 4: ATP comes and is sliced into ADP and P on the myosin head, which causes the muscle to recaulk, the process starts over

What are the phases of the sliding filament theory

Rigor mortis

Post mortem muscle contraction

Through an electrical impulse from the motor endplate (causes a ripple effect)

How do we get calcium into the sarcoplasmic reticulum to stimulate troponin

Excitation contraction coupling

All events in the motor endplate that result in a muscle contraction

2.0 micrometers

At what sarcomere length (in micrometers) can muscle fibers generate force according to the length-tension curve

You can't generate force because the muscle is already contracted

Why can't sarcomeres generate force at 1.8 micrometers according to the length-tension curve

You can't generate force because the muscle is too stretched out

Why can't sarcomeres generate force at 2.4 micrometers according to the length-tension curve