Test 4 A&P

what are the 5 general functions of muscle tissue

movement, posture, breathing, temperature control, heart/organ function

what muscle tissue is voluntary

skeletal muscle

which muscle tissues are involuntary

smooth and cardiac muscle

which muscle tissues have striations

skeletal and cardiac muscle

which muscle tissue does NOT have striations

smooth muscle

voluntary muscles

muscle contractions that you consciously control

involuntary muscles

muscle contractions that happen automatically without conscious control

what are striations

alternating light and dark band (stripes) seen in muscle fibers under a microscope

why do skeletal and cardiac muscles have striations

they have an organized arrangement of actin and myosin that create stripes

what are fascicles

bundles of muscle fiber

what are muscle fibers made of

myofibrils

what are myofibrils made of

myofilaments

what are 2 major myofilaments

actin and myosin

which myofilament is thin

actin

which myofilament is thick

myosin

sarcomere

the functional unit of muscle that contracts

what proteins make up each sarcomere

actin and myosin

what neurotransmitter is released into the synaptic cleft

acetylcholine (ACh)

what does acetylcholine do

opens sodium Chanels in the muscle cell

what causes the muscle cell to depolarize

sodium entering the muscle cell

what happens after the muscle reaches threshold

calcium is released from the sarcoplasmic reticulum

what does calcium bind to

troponin

what happens when calcium binds troponin

troponin moves tropomyosin away from the actin binding sites

what happens after tropomyosin moves

myosin binds to actin

what causes the power stroke

ADP and phosphate leave myosin, causing it to pivot

what causes myosin to release from actin

ATP binds to myosin

what does ATP do to calcium

pumps calcium back into the sarcoplasmic reticulum

what happens when calcium leaves troponin

tropomyosin covers the actin binding sites again

what pump resets the muscle after contraction

the sodium potassium pump

what enzyme breaks down acetylcholine

acetylcholinesterase

what is the role of acetylcholinesterase

breaks down acetylcholine to stop muscle stimulation and prevent another contraction

what is neuromuscular junction

the place where a motor neuron communicates with a muscle fiber

can one neuron stimulate multiple muscle fibers

yes

what is a threshold

the level of depolarization needed for a cell to activate

what does depolarize mean

to become less negative (remove charge)

what is the all-or-none principle

if threshold is reached, the cell activates. if not, it resets

what are the 3 muscle types

slow oxidative (type l ), fast oxidative glycolytic (type lla), and fast glycolytic (type llx/llb)

where are slow oxidative fibers commonly found

postural muscles

where are fast glycolytic fibers commonly found

muscles used for quick, powerful movements

how much ATP does creatine phosphate produce

1 ATP

how long does the creatine phosphate system last

about 10 seconds

how much ATP does anaerobic respiration produce

2 ATP

does anaerobic respiration require oxygen

no

what builds up during anaerobic respiration

lactic acid

how much ATP does aerobic respiration produce

about 36 ATP

does aerobic respiration require oxygen

yes

what causes oxygen dept

lactic acid buildup from anaerobic respiration

why does the body need extra oxygen after exercise

to convert lactic acid back into glucose

what is a concentric contraction

the muscle shortens while producing force

what is an eccentric contraction

the muscle lengthens while producing force

what is an isometric contraction

the muscle produces force without changing length

what is hypertrophy

an increase in muscle size

what is atrophy

a decrease in muscle size

what is the origin of a muscle

the attachment to the bone that usually does not move

what is the insertion of a muscle

the attachment to the bone that moves during contraction

can a muscle have multiple origins

yes

what is an agonist

the prime mover responsible for a movement

what is a synergist

a helper muscle that assists the agonist

what is an antagonist

the muscle that relaxes or opposes the agonist

what do flexors do

bend a joint

what do extensors do

straighten a joint

what does longus mean

long muscle

what does brevis mean

short muscle

what does carpi refer to

wrist

what does digatorum mean

fingers or toes

what does hallux refer to

big toe

what does pollux refer to

thumb

what does indices refer to

index finger

what does minimi refer to

little finger

list the 14 steps of muscle contraction in order

1. ACh released

2. Na⁺ enters

3. Depolarization

4. Ca²⁺ released

5. Ca²⁺ binds troponin

6. Tropomyosin moves

7. Myosin binds actin

8. Power stroke (ADP + Pi leave)

9. ATP binds myosin

10. Myosin releases

11. Ca²⁺ pumped back into SR

12. Tropomyosin covers actin

13. Na⁺/K⁺ pump resets membrane

14. ACh broken down by acetylcholinesterase

sternocleiodmastiod function

flexes the neck and rotates the head

sternocleiodmastiod orgin and insertion

orgin: sternum and clavicle

insertion: temporal bone

trapezius function

elevates, retracts, depresses, and rotates the scapula; extends the neck

trapezius orgin and insertion

orgin: skull and vertebrae

insertion: clavicle and scapula

pectorales major function

flexes, adducts, and medially rotates the arm

pectorals major orgin and insertion

origin: clavicle, sternum, ribs

insertion: humerus

pectoralis minor function

pulls the scapula downward and forward

pectoralis minor orgin and insertion

orgin: ribs

insertion: scapula

deltoid function

abducts the arm

deltoid orgin and insertion

origin: clavicle and scapula

insertion: humerus

supraspinatus function

initiates arm abduction

supraspinatus origin and insertion

orgin: scapula

insertion: humerus

infraspinatus function

laterally rotates the arm

infraspinatus orgin and insertion

origin; scapula

insertion: humerus

subscapularis function

medially rotates the arm

subscapularis orgin and insertion

orgin: scapula

insertion: humerus

teres minor function

laterally rotates the arm

teres minor orgin and insertion

orgin: scapula

insertion: humerus

teres major function

extends, adducts, and medially rotates arm

teres major orgin and insertion

origin: scapula

insertion: humerus

latissimus dorsi function

extends, adducts, and medially rotates the arm

latissimus origin and function

origin: vertebrae, ribs, and illium

insertion: humerus

rectus abdominas function

flexes the trunk

rectus abdominas origin and function

origin: pubis

insertion: illium

internal oblique function

rotates and flexes trunk

internal oblique insertion and origin

origin: iilium

insertion: ribs

biceps brachii function

flexes the elbow and supinates the forearm

biceps brachii origin and insertion

origin: scapula

insertion: radius

brachialis function

primary flexor of the elbow

brachialis orgin and insertion

orgin: humerus

insertion: ulna