bio final lec exam

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functions of muscle

movement, stability, communication, control of body openings, heat production, glycemic control, myokine secretion

universal characteristics of muscle

excitability, conductivity, extendibility, contractility, elasticity

skeletal muscle

voluntary striated muscle with multiple nuclei that fuse

connective tissues of muscle tissue

epimysium covers entire muscle, perimysium covers fascicle(bundle of muscle fibers), endomysium covers individual muscle fibers

structure of muscle in order

myofilament → sarcomere → myofibrils → muscle fiber → fascicle → entire muscle

function of calcium in muscle fiber

calcium acts as key messenger that triggers contraction by allowing myosin and actin filaments to bind

actin microfilaments

two strands of F-actin made up of G-actin beads coil together to form THIN filaments

myosin

several hundred golf-head shaped strands that make up THICK filaments

troponin and tropomyosin

tropomyosin strands cover the active site of the G-actin beads and troponin are attached to tropomyosin strands which allow calcium to bind

elastic filaments

made up of titin and link Z-discs to thick filaments; prevents overstretching

Z-discs

protein structure that anchors thin (actin) filaments at the boundaries of each sarcomere

Dystrophin

found in sarcolemma and connects the myofilaments to the endomysium

H band

bare zone

I band

zone of only thin filamentsA

A band

thick and thin filaments overlapping

M line

structure that anchors myosin filaments, maintaining the muscle's structural integrity during contraction

sarcomere

basic contractile unit of striated muscle

nerve-muscle relationship

one nerve controls many muscle fibers; without nerves, we can’t move our muscles

motor unit

one nerve fiber and all the muscle fibers innervated by it; can be small and large depending on amount of muscle fibers it controls

neuromuscular junction

junction enclosed by basal lamina and releases Ach through exocytosis and passes through synaptic cleft to bind to receptors in sarcolemma of muscle

excitation of muscle fiber

1. nerve signal arrives at axon terminal

2. calcium stimulates synaptic vesicles to release Ach

3. Ach diffuses across synaptic cleft and binds to receptors

4. Two Ach molecules bind so Na+ flows quickly in while K+ flows out

5. triggers an action potential that cause the excitation of the muscle fiber.

length-tension relationship

overstretched - weak tension because no overlap b/w thin and thick filaments
overcontracted - weak tension because thick filaments butt against Z line

Myogram

shows the timing and strength of a muscle’s contraction

factors that determine strength of twitches

muscle fatigue, hydration, temperature, strength of stimulus, frequency of stimulus, how stretched the muscle was (length-tension relationship)

immediate energy

myoglobin carries oxygen and is quickly depleted → phosphagen system uses myokinase and creatine kinase to reuse ADP to make more ATP

short-term energy

phosphagen system exhausted → lactate fermentation anaerobic accumulates lactic acid

long-term energy

respiratory and cardiovascular systems “catch up” and deliver oxygen to muscles fast enough for aerobic respiration again.

fatigue and endurance

potassium accumulation, ADP/Pi accumulation, fuel depletion, electrolyte loss, central fatigue

Excess Post-exercise Oxygen Consumption (EPOC)

to meet a metabolic demand, you breathe heavily not only during strenuous exercise but also for several minutes afterward

slow twitch fiber (red)

slow oxidative, type I, slow to stimulation and used in endurance exercise

fast twitch fiber (white)

fast glycolytic, type II, fast to stimulation and used in high-intensity or strength exercise

cardiac muscle

must contract with regular rhythm in unison even when sleeping plus must be highly resistant to fatigue

smooth muscle

response of smooth muscle is slow, but it can remain contracted for a long time without fatigue; found in walls of larger organs

all classification of muscles

fusiform, parallel, triangular, unipennate, bipennate, multipennate, circular

prime mover (agonist)

muscle that produces most of the force (brachialis)

synergist

muscle that aids the prime mover (biceps brachii)

antagonist

muscle that oppose the prime mover (triceps brachii)

fixator

muscle that prevents a bone from moving (rhomboids)

muscles of chewing

temporalis, masseter, medial and lateral pterygoid muscle

under the neck muscles

suprahyoid: stylohyoid and digastric muscles
infrahyoid: thyrohyoid muscles

flexors of the neck

sternocleidomastoid and three scalenes

extensors of neck

trapezius, splenius capitis, splenius cervicis

core muscles

external oblique, internal oblique, transversal abdominal, rectus abdominis (6-pack)

muscles in back

trapezius, latissimus dorsi, serratus posterior superior, serratus posterior inferior, erectus spinae

anterior group of shoulder muscles

pectoralis minor and serratus anterior (really close to side of ribs) boxer muscle

posterior group of shoulder muscles

trapezius, levator scapulae, rhomboid minor, rhomboid major

rotator cuff muscles (SITS)

supraspinatus, infraspinatus, tere minor, subscapularis (hugging the scapula all around) — reinforces the joint capsule and hold the head of the humerus in the glenoid cavity

other scapular muscles

deltoid (shoulder), teres major (lats), coracobrachialis (bicep medial)

axial muscles on shoulder joint

pectoralis major and latissimus dorsi — bear the primary responsibility for attaching the arm to the trunk and are prime movers of the shoulder joint.

elbow joint muscles

brachialis, biceps brachii (2 heads), triceps brachii (3 heads)

Iliopsoas

Iliacus (fills most of iliac fossa) + Psoas major (stems from lumbar vertebrae) both meet at lesser trochanter near femur

Gluteus Maximus

largest and most prominent muscle that makes up the bulk of your butt (buttocks)

quadriceps femoris

rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius → all converge on a single quadricep (used when kicking a ball or taking a step) vastus intermedius deep to rectus

sartorius

runs from hip to inner knee (lateral to medial) for almost all lower-body movements, especially sitting cross-legged

posterior compartment of thigh

hamstring muscles, biceps femoris, semitendinosus, semimembranosus → flexes knee or bend knee, extends hip, rotate femur

Central Nervous System (CNS)

brain and spinal cord in cranium and vertebral column

Peripheral Nervous System (PNS)

sensory division → carries signals from various receptors to the CNS
motor division → carries signals from the CNS mainly to gland and muscle cells that carry out the body’s responses

Somatic Sensory Division

carries signals from receptors in the skin, muscles, bones and joints

Visceral Sensory Division

carries signals mainly from the viscera of the thoracic and abdominal cavities such as the heart, lungs, stomach and urinary bladder.

Somatic Motor Division

carries signals to the skeletal muscles like voluntary muscle contractions and automatic reflexes

Visceral Motor Division

automatic nervous system that operates involuntarily — consists of sympathetic and parasympathetic division

Sympathetic Division

fight or flight signals

Parasympathetic Division

rest and digestion signals

Sensory Neuron

Specialized to detect stimuli and transmit the information to the CNS

Interneurons

central processing units that receive signals from many other neurons and use that for decision making, thinking, memory, feeling

Motor Neuron

send signals predominantly to muscle and gland cells, the effectors

structure of a neuron

cell body or neurosoma, axon and axon terminals, and dendrites

glial cells

supportive cell that protect the neurons and help them function (faster signals + nutrients + waste removal)

Multiple Sclerosis (MS)

autoimmune disease of CNS where the immune system mistakenly attacks myelin, the protective sheath around nerve fibers, disrupting nerve signals

Myelin and Myelin Sheath

spiral layer of insulation around a nerve fiber consisting of 80% lipid 20% protein

Resting Membrane Potential (RMP)

usually -70 mV because a big leakage of K+,
and a little bit leakage of Na+ INSIDE IS RELATIVELY NEGATIVE COMPARED TO OUTSIDE RELATIVELY POSITIVE

Excitation of A Neuron

sodium channels open up to disrupt the membrane potential which depolarizes the cellL

Local Potentials

small, short electrical signals, happens in dendrite and cell body, can be weak or strong (should i send a message)

Action Potentials

big, fast electrical signals, happen in axon (message freaking sent)

Unmyelinated fibers and Continous Conduction

in unmyelinated fibers, action potentials travel through continuous conduction kind of like slow dominoes

Myelinated fibers and Saltatory Conduction

in myelinated fibers, nerve signal jumps from node to node which is much faster kind of like an express train