Chapter 11 - Myofibers

What is this?

skeletal muscle model

A

sarcolemma

B

endomysium

C

nucleus of muscle cell

D

thick and thin filaments

E

myelinated axon

F

synaptic knob of axon terminal

G

mitochondria

What is this?

filament and dense region

H

myosin (thick) filaments

I

actin (thin) filaments

J

z-disk

K

sarcomere

What is this?

myofiber model

A

synapse

B

axon

A

synapse

B

axon

What is this?

myofiber model

What are skeletal muscle cells?

myofibers

Sarcolemma

plasma membrane of a myofiber

Endomysium

connective tissue that surrounds individual myofiber

Nucleus

houses DNA that codes for protein filaments

Thick filament

myosin

Thin filament

actin

Z-disk

dense region that separates one sarcomere from another

Sarcomere

functional unit within a myofiber, filaments between z-disk

Synapse

union between axon terminal and myofiber

Axon

long thin projection from a neuron that delivers a neurotransmitter

Myelinated Axon

transmission of action potential travels

Synaptic Knob of Axon Terminal

release the neurotransmitter, acetylcholine, which depolarizes the muscle cell and produce a contraction

Mitochondria

powerhouse of the cell, producing ATP

Myosin (thick) Filaments

use the energy of ATP to change shape, producing the power stroke of contraction

Actin (thin) Filaments

have binding sites for myosin

Origins

where a muscle group attaches to the bone that is not involved in the major movement during contraction

Insertion

the attachment of the muscle to the bone that is moved during contraction

Action

describes what type of movement is generated by the contracting muscle

Flexion

bending the elbow

Extension

straightening the elbow

Abduction

raising arms laterally

Adduction

dropping arms to side

Medial Rotation

toes toward midline (rotation of the hip)

Later Rotation

toes away from midline (rotation of the hip)

Elevation

shoulder shrugs up

Depression

dropping shoulder down

Pronation

palms down

Supination

palms up

Dorsiflexion

lifting of toes/dropping of heel

Plantarflexion

pointing of toes

Eversion

sole of foot away from the midline

Inversion

sole of foot towards the midline