Muscular System

which solution from the protocol had NO muscle contraction?

KCl+MgCl2

formed by supporting proteins holding thick filaments together in the center of the H zone

M line

as a result of glycerination process_______is no longer needed for muscle contraction to occur, which is different from normal muscle contraction physiology within our bodies

Calcium

layers of connective tissues from the innermost to the outermost

Endomysium, perimysium, epimysium

Center of A band Only thick filaments

H zone

contains ONLY thin filaments

I band

entire length of the filament; contains area of overlap with thin filament

A band

within our bodies, muscular contraction can last for as long as there is enough:

ATP and calcium

a combination of _______ and _______ forms the cross bridge during a muscle contraction cycle

Actin and troponin

striated muscle

skeletal and cardiac

combined with connective tissue and neural tissue

skeletal muscle

multinucleated and superficial

skeletal muscle

skeletal muscle > muscle fascicle > muscle fiber > myofibril > sarcomere

skeletal muscle fiber in order from largest to smallest

type of muscle fiber needed to: run a marathon

slow oxidative fibers

muscle with involuntary contractions

smooth and cardiac muscles

Non-striated muscle

smooth muscle

found in the walls of blood vessels

smooth muscle

found in walls of digestive, respiratory, urinary, and reproductive organs

smooth muscle

connects a Z disc to the M line of a sarcomere. helping stabilize the position of the thick filament

titin

proteins that are considered structural proteins

titin, alpha-actinin, myomesin, nebulin, dystrophin

what is the function of post synaptic calcium in muscle contraction?

to bind troponin, change shape and move tropomyosin from the active site

formed by transverse tubules and two terminal cisternae

triad

this protein is a component of the thin filament that will cover the myosin-binding sites on the actin molecules

tropomyosin

proteins that are considered regulatory proteins

tropomyosin and troponin

this protein is a component of the thin filament and is where calcium ions will bind to during skeletal muscle contraction

troponin

(T/F) a fiber is categorized as slow or fast depending on how rapidly the ATPase in its myosin heads hydrolyze ATP

true

(T/F) depolarization of the motor end plate is what causes post-synaptic calcium ions to be released from the sarcoplasmic reticulum

true

(T/F) fast glycolytic fibers have low myoglobin content, few blood capillaries, few mitochondria, and appear white in color

true

(T/F) fast oxidative-glycolytic fibers have a high intracellular glycogen level, which allows them to generate ATP by aerobic respiration

true

(T/F) skeletal muscle fibers that have a high myoglobin content are termed RED muscle fibers

true

(T/F) slow oxidative fibers are smallest in diameter and are the least powerful type of muscle fibers

true

(T/F) slow oxidative fibers generate ATP mainly by aerobic respiration

true

cardiac, skeletal, muscle

types of muscles

narrow, plate shaped regions of dense protein

z disc

muscle with voluntary contractions

Skeletal muscle

structure present: muscle fascicle membrane surrounding: epimysium

Skeletal muscle

invaginations of the sarcolemma; filled with extracellular fluid

T-tubules

main component of the thin filament that has an active myosin-binding site

actin

present in the Z discs, it will attach to actin and titin molecules

alpha actinin

SO Fibers: high capacity by aerobic respiration FOG fibers: intermediate capacity by aerobic respiration and anaerobic glycolysis FG Fibers: low capacity by anaerobic respiration

capacity for generating ATP and method used

single nucleus and deep

cardiac and smooth muscle

located in the heart

cardiac muscle

muscle with intercalated discs

cardiac muscle

which process is used to create ATP to provide energy to muscles?

cellular respiration

SO Fibers: red FOG fibers: red FG Fibers: white

color

ability of muscle to contract forcefully when stimulated

contractibility

SO Fibers: slow FOG fibers: fast FG Fibers: fast

contraction velocity

this might help transmit the tension generated by sarcomeres to tendons

dystrophin

ability of muscle to return to original length and shape after contraction or extension

elasticity

ability to respond to certain stimuli by producing action potentials

electrical excitability

connective tissue surrounding each individual muscle fiber

endomysium

connective tissue wrapping around muscle

epimysium

What is the role of acetylcholine in skeletal contraction?

excitatory neurotransmitter that helps in skeletal contraction

ability of muscle to stretch without damage

extensibility

(T/F) A triad consists of the motor end plate and its flanking terminal cisternae

false

(T/F) fast oxidative-glycolytic fibers are fast-twitch fibers adapted for intense movements of short duration like weight lifting or throwing a ball

false; best adapted for walking and sprinting

(T/F) fast glycolytic fibers are intermediate in diameter and have a high resistance to fatigue

false; moderate resistance to fatigue

type of muscle fiber needed to: weight lifting for body building

fast glycolytic fibers

type of muscle fiber needed to: walk to the bus stop

fast oxidative glycolytic fiber

SO Fibers: high FOG fibers: intermediate FG Fibers: low

fatigue resistance

SO Fibers: smallest FOG fibers: intermediate FG Fibers: largest

fiber diameter

smaller structure within myofibrils

filaments

serves as storage form of glucose; can be broken down and used to synthesize ATP

glycogen

SO Fibers: postural muscle such as the neck FOG fibers: lower limb muscles FG Fibers: upper limb muscles

location where fibers are abundant

SO Fibers: have many FOG fibers: have many FG Fibers: have few

mitochondria and capillaries

SO Fibers: first FOG fibers: second FG Fibers: third

order of recruitment

connective tissue surrounding a bundle of muscle fibers

perimysium

SO Fibers: maintaining posture and aerobic endurance activities FOG fibers: walking/sprinting FG Fibers: rapid intense movements of short duration

primary functions of fibers

SO Fibers: slow FOG fibers: fast FG Fibers: fast

rate of ATP hydrolysis by myosin ATPase

What is the role of acetylcholinesterase in skeletal contraction?

reuptake of NT into pre-synaptic terminal breaks down any ACh that is present in the synaptic cleft

plasma membrane of a muscle fiber

sarcolemma

repeating units of myofibril

sarcomere

thick and thin filaments

sarcomere

surrounded by the sarcolemma; the cytoplasm of the muscle fiber

sarcoplasm

storage center of calcium in relaxed muscle

sarcoplasmic reticulum

makes up the thick filaments. consists of 2 heads and a tail

myosin

proteins that are considered contractile proteins

myosin and actin

wraps around the entire length of each thin filament. it also helps to anchor thin filaments to Z discs in addition to regulating the length of thin filaments during development

nebulin

1- action potential occurs in the somatic motor neuron 2- ACh (excitatory neurotransmitter for skeletal muscle) that is stored in the synaptic vesicle of the synaptic end bull is released and diffused across the synaptic cleft 3- ACh binds to nicotinic ACh receptors on the motor end plate 4- Depolarizing graded potential called end plate potential (EPP) is generated 5- Adjacent regions of the sarcolemma are then depolarized, resulting in the generation of a muscle action potential. This action potential propagates through the muscle fiber membrane in both directions away from the NMJ towards the end of the fiber 6- At the onset of muscle fiber contraction, the sarcoplasmic reticulum releases calcium ions into the sarcoplasm 7- The calcium ions then bind to troponin, which moves tropomyosin away from myosin binding sites on actin 8- Now that the binding sites are free, ATP is hydrolyzed into ADP and a phosphate. This energizes the myosin head which then assumes the "cocked" position 9- The energized myosin head then attaches to the myosin binding site on actin and a phosphate is released. This is referred to as the "crossbridge" 10- The myosin head pivots changing its position from 90 degrees to 45, pulling the thin filament past the thick filament towards the center of the sarcomere. This is referred to as the power stroke 11- Another molecule of ATP binds to the ATP binding site on myosin allowing for myosin to detach from actin

muscle contraction steps

structure present: muscle fibers membrane surrounding: perimysium

muscle fascicle

structure present: myofibrils membrane surrounding: endomysium

muscle fiber

contractile element of the skeletal muscle fiber; containing thick and thin filament

myofibril

structure present: sarcomeres membrane surrounding: sarcoplasmic reticulum

myofibril

red, oxygen binding protein that is only found in the muscle; stores oxygen until it is needed by the mitochondria for ATP

myoglobin

SO Fibers: large amount FOG fibers: large amount FG Fibers: small amount

myoglobin content

forms the M line of the sarcomere. it also binds to titin molecules and connects adjacent thick filaments to one another

myomesin