Chapter 10 Flashcards
Treactive to stimuli from nervous system or environment, generate electrical mechanical response
excitability
cells actively shorten (contract) upon stimulation, generates tension
contractility
cells can length (extend) when pulled
extensibility
tendency to rebound (recoil) to some resting length after contraction or extension
elasticity
multinucleate voluntary movement no center nucleus striated pattern long, cylindrical
skeletal muscle
intercalated discs uninucleate cells, central branching pattern involuntary walls of heart striations
cardiac muscle
spindle=shaped no striations central nucleus form layers/sheets of cells involuntary blood vessels, hollow organs
smooth
surrounded by epimysium.
bundle of fascicles, each surrounded by perimysium
whole muscle
bundle of cells, each surrounded by endmysium
fascicle
contains cylindrical bundles of proteins
cell
bundle of proteins
myofibril
surrounds the whole skeletal muscle
epimysium
surrounds the muscle fascicle (group of cells)
perimysium
surrounds the cells within the muscle fascicle
endomysium
functions of skeletal muscle
body movement posture temperature regulation storage and movement of materials support
multiple fascicles housing many muscle fibers, connective tissue coverings, blood vessels, nerve fibers
muscle
covered by epimysium
a bundle of muscle fibers separated from other bundles of fibers by a dense irregular connective tissue covering
fascicle
covered by perimysium
elongated, multinucleate, cylindrical fiber, contains myofibrils, separated from other fibers
muscle fiber
covered by endomysium
long, cylindrical contractile element within muscle fiber; composed of myofilaments; exhibits striations
myofibril
short contractile proteins of two types: thick (myosin) and thin (actin, tropomyosin, and troponin)
myofilaments
attaches muscle to bone
tendon
tendon forms a thin, flattened sheet
aponeurosis
less mobile attachment
origin
more mobile attachment
insertion
plasma membrane of a muscle fiber
sarcolemma
cytoplasm of a muscle fiber
sarcoplasm
smooth endoplasmic reticulum in a muscle fiber
stores Ca2+ for muscle contraction
sarcoplasmic reticulum
expanded ends of the sarcoplasmic reticulum that are in contact with the transverse tubules
terminal cisternae
narrow, tubular extensions of the sarcolemma into the sarcoplasm, contacting the terminal cisternae; wrapped around myofibrils
transverse tubules
protein myofilament composed of myosin
thick filament
protein myofilament composed of actin, troponin, and tropomyosin
thin filament
alternating arrangement of thick and thin filaments give what appearance?
striations
where are the myosin held together at?
M line on thick myofilaments
where are the actin held together?
Z line on thin filaments
sacromeres are arranged in series from what line to what line?
Z to Z line
The skeletal muscle is surrounded by what layer?
epimysium
The muscle fascicle is surrounded by what layer?
perimysium
The muscle fiber is surrounded by what layer?
endomysium
the myofibril is surrounded by what layer
sarcoplasmic reticulum
-consists of sarcomeres (Z to Z)
neurons that are connected to skeletal muscle cells are
motor neurons
place where neuron connects to muscle cell
neuromuscular junction
motor unit
the neuron + muscle cells it controls
what causes the release of calcium
stimulation of a muscle cell by a motor neuron from the SR into the cytoplasm
calcium triggers?
a cycle of activity (called the cross bridge cycle) that will bring Z lines of sarcomeres closer together
cross bridge cycling
involves interaction of muscle proteins (actin, myosin, troponin, tropomyosin) and requires ATP for energy
type 1 fibers
slow, oxidative
-small, slower contracting, dark (red), good at aerobic metabolism (fatigue resistant), low force generation
type 2B fibers
fast, glycolytic
-big fast contracting, pale (white), good at anaerobic metabolism (easily fatigued), high force generation
type 2A fibers
fast, oxidative
-somewhere in between “intermediate”, fast contracting but somewhat fatigue resistant, medium force generation
circular pattern
orbicularis
around an opening, sphincter
parallel pattern
run parallel to long axis of muscle
biceps brachii muscle
convergent muscle
fibers converge on single tendon and muscle often triangular
pectoralis muscles
pennate
fibers attached to tendon at oblique angle; like a feather
unipennate: extensor digitorum muscle
bipennate: rectus femoris muscle
multi: deltoid muscle
characteristics of cardiac muscle
- electrically interconnected with one another
- intercalated discs contain ion channels
- electrical activity can easily spread from cell to cell
characteristics of smooth muscles
- cells arranged in sheets (not bundles)
- spindle shaped
- one nucleus
- actin is attached to dense bodies
- myosin scattered throughout cell
- adjacent cells bound together physically and are electrically coupled
contraction of smooth muscle
- causes shortening and twisting
- contraction slow, smooth, sustained and resistant to fatigue
- involuntarily controlled