muscular system notes

skeletal, smooth, cardiac

3 types of muscle tissue

excitable, contractile, extensible, elastic

4 characteristics of muscles

hypertrophy

muscle fiber diameter expands (lifting) or gets stretchier (stretching)

atrophy

muscle fiber diameter shrinks, moves faster than hypertrophy

origin

attachment of a muscle that remains relatively fixed during muscular contraction

insertion

The attachment of a muscle tendon to a moveable bone or the end opposite the origin

opposite

muscles usually end on the __ side of the joint

fascia/epimysium

outside muscle covering, where tendon attaches

tendon/aponeurosis

anchors the muscle to the connective tissue covering of a skeletal element or to the fascia of other muscles

fascicles

Bundles of muscle fibers wrapped in perimysium

perimysium

Connective tissue surrounding a fascicle

endomysium

Connective tissue surrounding a muscle fiber

muscle fiber

muscle cell

sarcolemma

muscle cell membrane

sarcoplasmic reticulum

specialized endoplasmic reticulum of muscle cells, stores calcium

sarcoplasm

cytoplasm of a muscle cell

myosin

The contractile protein that makes up the thick filaments of muscle fibers, has heads

actin

Thin filament of protein found in muscles, has binding site

tropomyosin

covers myosin binding sites on the actin molecules

troponin

regulatory protein that binds to actin, tropomyosin, and calcium

i band

light band, end of myosin to end of myosin, contains actin and Z line (2)

a band

dark area; extends length of the thick filaments (7)

h zone

The region at the center of an A band of a sarcomere that is made up of myosin only. It gets shorter (and may disappear) during muscle contraction.

m line

center of sarcomere

z line

A dark thin protein band to which actin filaments are attached in a striated muscle fiber, marking the boundaries between adjacent sarcomeres.

sarcomere

Contractile unit of muscle

crossbridge

this forms when the myosin heads attach to actin during muscle contraction

powerstroke

the myosin pulls on the actin and the actin slides toward the middle of the sarcomere

cocking

muscle goes back to normal

ATP

__ binds to myosin and causes relaxation

rigor mortis

muscle stays contracted without ATP during death

isotonic

contraction that moves a load (bicep curl)

concentric

muscle shortens

eccentric

muscle lengthens

isometric

contraction without movement (wall sit, plank)

tone

state of partial contraction that allows for easier contraction/reaction

creatine phosphate

An energy storage molecule used by muscle tissue. Can phosphorylate ATP to generate energy quickly (lasts about 10s)

anaerobic respiration

Respiration in the absence of oxygen. This produces lactic acid. (lasts about 40s)

aerobic respiration

Respiration that requires oxygen (lasts hours)

mental fatigue

brain tells body that it's tired, protective mechanism

ion imbalance

calcium, sodium, potassium imbalance, follows mental fatigue

longitudinal, circular

2 layers of smooth muscle

overload principle

increasing the intensity (resistance), frequency, or duration of the training above the levels normally expected

peristalsis

Involuntary waves of muscle contraction that keep food moving along in one direction through the digestive system.

stress-relaxation response

Responds to stretch only briefly, then adapts to new length; Retains ability to contract on demand;
Enables organs such as the stomach and bladder to temporarily store contents

all

smooth muscle can contract at __ lengths

hyperplasia

the enlargement of an organ or tissue because of an abnormal increase in the number of cells in the tissues, possible in smooth muscle

18

age of peak muscle control

same

males have more muscle mass, but __ number of fibers

fibers

skeletal and cardiac can't make more __ past adolescence, but smooth muscle can

30

muscle mass rapidly declines after age __ without exercise

prime mover

muscle with the major responsibility for a certain movement

antagonist

muscle that opposes the prime mover

synergist

muscle that aids a prime mover in a movement and helps prevent rotation

fixator

stabilizes the origin of a prime mover

location, shape, relative size, direction of fibers, number of origins, location of attachments, action

7 ways to name a muscle