bio 112 - chapter 8 - muscle info

what are muscles?

organs that generate force for movement

what are the 3 types of muscle tissue?

skeletal, smooth, cardiac

what is skeletal muscle tissue?

voluntary; striated

what is smooth muscle tissue?

involuntary, non-striated

what is cardiac muscle?

involuntary, striated, in heart-only

what does fascia surround?

surrounds and seperates muscle

what does epimysium surround?

surrounds whole muscle

what is the perimysium surround?

surrounds fascicles

what does the endomysium surround?

surrounds individual muscle fibers

what is the sarcolemma?

cell membrane

what is the sarcoplasm?

cytoplasm with many mitochondria & nuclei

what has thick filaments?

myosin

what has thin filaments?

actin, troponin, tropomyosin

striations = ?

organized sarcomeres

sarcomere

unit of contraction from Z line to Z line

sarcomere: I band

region containing actin only

sarcomere: A band

region with overlapping actin and myosin

sarcomere: H zone

region containing myosin only

sarcomere: M line

structure that holds myosin in place

function of the sarcoplasmic

stores and releases calcium

roles of the T-tubules

transmit impulses deep into the muscle fiber

what happens when the role of SR and T-tubules are combined?

trigger muscle contraction

definition of neuromuscular junction

communication site between motor neuron and muscle fiber

definition of synapse in muscle physiology

functional connection via acetylcholine

what is the motor end plate?

sarcolemma region with ACh receptors

synaptic cleft

gap between neuron and muscle fiber

sliding filament theory

myosin pulls actin inward to shorten the sacromere

role of ATPase on myosin

breaks ATP to power cross-bridge cycling

first step of muscle contraction

ACh released and binds the motor end plate

what is the effect of calcium binding troponin

exposes actin binding sites

what’s the cause of muscle relaxation

ACh breakdown, CA²+ reuptake, cross-bridge release

Immediate energy source for contraction

ATP

aerobic respiration ATP yield

28 ATP

anaerobic respiration products

2 ATP and lactic acid

definition of oxygen debt

extra O2 needed to convert lactic acid and replenish ATP stores

what causes muscle fatigue?

Low ATP, electrolyte imbalance, lactic acid buildup

fast twitch fiber characteristics

anaerobic, powerful, fatigue quickly

slow-twitch fiber characteristics

aerobic, fatigue-resistant, many mitochondria

definition of muscle twitch

single contraction and relaxation

summation

frequent stimuli produce stronger contraction

tetany

sustained contraction

recruitment

activation of more motor units for stronger force

isotonic contraction

muscle shortens to produce movement

isometric contraction

tension without shortening

smooth muscle characteristics

involuntary, non-striated, slow, fatigue-resistant

cardiac muscle characteristics

striated, branched, involuntary, rhythmic

what is the origin of a muscle?

fixed attachment point

what is the insertion of a muscle called?

movable attachment point

what is agonist muscle?

prime mover of an action; main muscle

what is synergist muscle?

helper

what is antagonist muscle?

opposes action

what are levers?

bones and joints act as levers

naming criteria: size

muscles can be named by relative size (major, minor, longus, brevis.)

naming criteria: shape

muscles can be named by their geometric form (deltoid = triangle)

naming criteria: location

muscles can be named by the region or bone they are near

naming criteria: action

muscles can be named by the movement they produce (flexor, extensor)

naming criteria: fiber direction

muscles can be named by orientation of fibers (rectus, oblique, transverse.)

naming criteria: attachments

muscles can be named by their origin and insertion points

biceps brachii name meaning

two heads located in the arm

deltoid name meaning

triangular-shaped muscle of the shoulder

sternocleidomastoid name meaning

attaches to the sternum, clavicle, and mastoid process

what are the muscles of facial expression

orbicularis oculi, orbicularis oris, zygomaticus

muscles of mastication

masseter, temporalis

muscles that move the head

sternocleidomastoid, splenius capitis

muscles of the pectoral girdle

trapezius, serratus anterior

major arm muscles

deltoid, pectoralic major

major forearm muscles

biceps brachii, triceps brachii

muscles of the hand

flexors and extensors of wrist and digits

muscles of the abdominal wall

obliques, transversus abdominal, and rectus abdominis

muscles of the pelvic floor

levator ani, coccygeus

muscles of thigh

gluteal, adductors, quadriceps, hamstrings

muscles of the leg and foot

gastrocnemius, tibialis anterior, soleus, peroneal