Skeletal Muscle Histology

What is the function of skeletal muscle?

What is the function of skeletal muscle?

generates contractions leading to movement

the interactions of ________ and __________ allow skeletal muscles to contract

actin and myosin

What structural components are important to the function of skeletal muscle?

contractile proteins, multi-nucleated cells, mitochondria, CT and blood supply

dense irregular CT that surrounds the entire muscle

epimysium

loose Ct that surrounds each fascicle

perimysium

loose Ct that surrounds each individual muscle fiber

endomysium

Function of mysium layers

pull on surrounding CT where it connects to the tendons

1 muscle cell is made up of many __________

myofibrils

found inside myofibrils

myofilaments (actin and myosin)

what makes up a triad?

1 piece of t-tubule and 2 pieces sarcoplasmic reticulum

inside part of external layer of myofiber that faces the myofibrils

sarcolemma

outside part of external layer of myofiber

external lamina

exposed to the extracellular space and carry ECF, surround each myofibril

t-tubules

what does the sarcoplasmic reticulum contain?

ICF (calcium)

receptors of t-tubules that sense an action potential

DHP receptors

receptors on t-tubules that messages are relayed to

ryanodine (RyR) receptors

part of the sarcomere only consisting of actin filaments

I band

part of the sarcomere only consisting of myosin tails

H band

Center line, anchor for myosin

M line

how long is a sarcomere?

from one z-line to the next

contractile units of muscle

sarcomeres

area of overlapping actin and myosin

A band

During contraction, which parts of the sarcomere get smaller?

I band and H band

run in parallel with muscles and sense stretch

Muscle spindles

found at the muscle tendon junction, sense load on muscles

golgi tendon organs

cell division, used to grow muscles when we are very young

hyperplasia

muscle growth by increasing the size of already existing fibers which creates more contractile proteins

hypertrophy

what makes up the majority of a satellite cell?

DNA

X linked genetic disorder that causes muscle weakness, wasting, and cell death

Duchenne’s Muscular Dystrophy

which part of myosin does actin bind with?

the head