midterm Flashcards

Question

possible effects of caffiene

Answer 1

enhances motoneuronal excitability increases calcium release from SR improves aerobic endurance peformance, muscular endurance, not so much anaerobic performance

Answer 2

locomotion body posture thermal regulation venous

Answer 3

type 1(slow) subdivisions type 1, type 1c type II (fast) subdivisions: type iic, type IIac, type IIa, type IIax, type IIx, type IIb

Answer 4

primary means of differentiation/classification based on: 1)myosin heavy chains (myosin ATPase activity) 3 isoforms 2)type of motor neuron innervation - "twitch" properties 3)biochemical pathways used to produce energy "metabolic pathways"

Answer 5

type 1 low myosin ATPase activity type IIa high myosin ATPase activity type IIX higher myosin ATPase activity type IIb highest myosin ATPase activity type IIb is denoted as type IIx more accurate for humans however newer type IIb subtype

Answer 6

type i: "slow" or "slow twitch" type IIa: "fast-fatigue resistant" or fast twitch a (FTa) type IIX: "fast fatiguable" or Fast twitch x (FTx)

Answer 7

type i: slow oxidative/ aerobic metabolism type iia: fast oxidativce glyolytic/ anaerobic metabolism type IIx: fast glycolytic/ anaerobic metabolism

Answer 8

low myosin ATPase activity less extensive SR slower Ca release and uptake by SR slowest contracting, least fatiguable aerobic metabolism (higherst number oxidative enzymes) large and numerous number of mitochondria highest in myoglobin

Answer 9

high myosin ATPAse extensive SR network rapid Ca release and uptake by SR high rate of crossbridge turnover fast contractions capable of force generation fatigue quick rely on anaerobic metabolism (glycolytic enzymes) low in myoglobin

Answer 10

is a protein in your muscle responsible for transporting oxygen from the muscle membrane-capillary interface to the mitochondria myoglobin gives the muscle a red pigmentation

Answer 11

because of the amount of myoglobin is higher in type 1

Answer 12

muscle biopsy: muscle cross section (on a cover slip place in histo jar) based on the sensitivity of the muscle fibers myosin ATPase to different Ph environments FT fibers- when exposed to an acid environment myosin ATPase becomes inactive ST fibers- when exposed to an alkaline environment myosin ATPase becomes inactive

Answer 13

type IIa +13% type I no change type IIx -13% cannot convert fast fibers to slow fibers can have shift b/w type IIx to type IIa fibers

Answer 14

average person 45-55% ST fibres FT distribution approx equal across IIa and IIb elite athletes tend to demonstrate the greatest differences between distribution and performance. power athletes such as sprinters: high percent of fast twitch/ type II fibers endurance athletes such as distance runners: high percent of slow twitch/type I fibers

Answer 15

muscle fiber alignment fibre length to muscle length ratio energy production capacity twitch characteristics

Answer 16

long axis of muscle determines fiber arrangement fusiform: long fibers, high FL: ML ratio hamstrings spindle like greater ROM pennate: short fibers, low FL: ML ratio fan like fasicles quad fan like higher force

Answer 17

muscle force varies with the length of the muscle this variation in force is due to variation in actin-myosin overlap optimal force is going to be somewhere in the middles cross bridges dont over lap or are not too far optimal length for most amount of force

Answer 18

at any absolute force the speed of movement is greater in muscle with higher percent of fast twitch fibers the maximum velocity of shortening is greatest at the lowest force (true for both slow and fast twitch fibers) velocity increases, the force decreases

Answer 19

typical moves entire force velocity curve upward adn to the right fast velocity you have more increase in force slow velocity you have less increase in force

Answer 20

muscle action isometric= o velocity concentric= as velocity increases, max force decreases eccentric= as velocity increases, mac force increases

Answer 21

central nervous system (CNS) analyze and organize information motor system planning and commands, primary sensory spine and brain peripheral system outputs CNS commands and sends sensory info to the CNS primarily motor (movement and motor control)

Answer 22

afferent: relay sensory information from peripheral to the CNS along posterior column efferent: relay info from CNS to the peripheral or away from the brain along pyrimidal tract somatic nerves, autonomic nerves 20:1 ratio of afferent (sensory) to efferent motor)

Answer 23

somatic neurons (aka motor neurons) make up the somatic nervous system innervate skeletal muscle voluntary autonomic neurons (aka involuntary neurons) make up the autonomic nervous system activate smooth muscle, cardiac muscle, sweat and salivary glands sympathetic (flight or fight) and parasympathetic (rest and digest)

Answer 24

voluntary movements reflexes rhythmic movements

Answer 25

require integration at the cerebral cortex learned movements may become "reflexive." muscle memory ex) shooting a basketball

Answer 26

sensory input (vision, vestibular, muscle) can be modulated by higher brain centers involed in posture doesnt need to send a signal to do example) catching your balance from tripping

Answer 27

voluntary and reflexive initiated by cerebral cortex can be sustained without input of brain example running

Answer 28

central pattern generator (CPG) the CPG is a neural network in the lower part of the spinal cord that is thought to control locomotion it does not require input from higher brain centers or reflexes, but the CPG output can be modified by input from the brain or reflexes

Answer 29

basic mechanism to process "autonomic" muscle action- involuntary peripheral stimulus causes afferent neuron impulses to enter spinal cord afferent neurons interconnect (synapses) with interneurons in the spinal cord to relay info to the CNS efferent signals return via motor neurons to the muscles muscle responds

Answer 30

touching hot pan pain receptors in fingers transmit sensory info to the spinal cord (afferent) efferent neurons activate the apropriate muscle response "reflex" action and muscular response occurs before the pain Stimulus can reach the brain and tell the body to feel the pain

Answer 31

motor unit represents an alpha motor neuron and the fibers it innervates motor neuron pool represents a collection of alpha motor neurons that innervate one muscle.

Answer 32

small motor unit: only have a few fibers/ motor neuron (those involved in fine movements like finger actions, eye action) complex, precise movement larger motor unit: may have hundreds or thousands of muscle fibers/ motor neuron ( those involved in gorss movements like walking) simple movement

Answer 33

all muscle fibers within a given motor unit are the same fiber type (type i or type ii) if motor unit is activated (by an higher brain centers) all the muscle in that unit contract

Answer 34

motor neurons may recieve input from other neurons orginating higher up in the central nervous system or the brain itself they also may input from reflexes originating in the limbs (peripheral)

Answer 35

dendrites: recieve impulses and direct toward cell body cell body: control center axon: delivers impulse to muscle schwann cell: covers bare axon myelin sheath: electrical insulator of the axon neurilemma: membrae covering the myelin sheath nodes of ranvier: permit depolarization of axon

Answer 36

action potential is propagated along the axon of the motor neuron axon is covered in myelin at certain points along the axon, there is a space in the myelin (nodes of ranvier) nerve fiber conduction speed increases in direct proportion to fibers diameter and myelin thickness so the more myelin or thicker the axon, the faster conduction velocity of the axon larger motor neurons have thicker axons

Answer 37

axon diameter myelin thickness

Answer 38

interface/junction between the end of a motor neuron and muscle fiber transmits nerve impulses to initiate muscle action anatomical features of NMJ -presynaptic terminals -synaptic cleft -postsynaptic membrane

Answer 39

sodium is low on inside as compared to outside of the cell potassium is high on inside compared to outside the cell controlled by membrane permeability

Answer 40

when charges are different across membrane the fiber cell is more negatively charged on the inside because there are more Na ions outside compared to K ions inside

Answer 41

depolarization: membrane potential becomes more positive ( >-70mV, closer to 0 or above) repolarization: membrane potential becomes more negative (back towards RMP) hyperpolarization: membrane potential becomes more negative than resting membrane potential than resting membrane potential (<-70mV)

Answer 42

endpoint potential: depolarization or hyperpolarization of MP does not result in muscle contraction action potential: substantial depolarization of MP results in muscle contraction depends on EPSP and IPSP

Answer 43

excitatory post synaptic potential: depoalrizes of postsynatpic membrane, facilitates to AP inhibitory: hyperpolrizations of post synaptic membrane inhibit AP hyper polarizations are endpoint potentials EPPS

Answer 44

temporal summation: one or few neurons can deliver repetitive suthreshold stimulus over a short period of time spatial summation: a bunch of excitatory post synaptic potentials can be delivered from different presynaptic terminals AP can occur when summing of each individual effect results in threshold for excitation

Answer 45

membrane permeability

Answer 46

impulse travels down axon terminal calcium channels open and ca diffuses into axon causes fusion of "synaptic vesicles" containing acetylcholine (ACH) with membrane of axon vesicles release ACH into the synaptic cleft ACH binds on receptors on muscle membrane and excites the membrane, changing its permeability of membrane (influx/efflux of Na and K) channels open to allow sodium in and potassium out depolarization generates an EPP, if at threshold an AP generated

Answer 47

ACH is broken down by cholinesterase to repolarize postsynaptic membrane axon resynthesises acetic and choline to form ACH so that the entire process is ready to go again

Answer 48

slow twitch recruited first than fast twitch type II are innervated by larger neurons and take more to recruit, than slow twitch fibers, hence type I is recruited first

Answer 49

measure electrical signals created by muscle surface electrodes needle electrodes importance: allows you to assess which muscles are activated during exercises allow you to assess amount muscles are activated allows you to assess which muscles are under strain during work situations (important for injury prevention0

Answer 50

used to determine the frequency of firing often used to access fatigue would be highe in type II because it relaxes faster meaning there is more firing

Answer 51

before a muscle relaxes from a contraction, if another electrical stimulus is applied force increases to a higher level this is due to increase release of Ca from the SR this Ca will bind more troponin, lifting tropomyosin, allowing more myosin-actin cross bridges

Answer 52

slow twitch because fast twitch can relax faster

Answer 53

force will summate up to maximal level with repetitive summation this maximal level is reached once all the sites for Ca on troponin have been occupied

Answer 54

1)CNS 2) peripheral nervous system 3) neuromuscular junction 4) muscle fiber

Answer 55

occurs from disruption in the chain of events between CNS and the muscle fiber

Answer 56

central fatigue: failure of the neurual drive or the initiation of action potential in the CNS bigger factor in endurance exercise hypoglemia impairs CNS function peripheral fatigue: fatigue occuring in the muscle cell occur due to sacrolemma T-tubules SR nutrition/metabolism

Answer 57

occurs at NMJ AP fails to cross from motor neuron to muscle fiber decline in neurontrasnmitter release

Answer 58

is our body awareness vestibular: where the body is in space proprioceptive: where the body is relative to other parts of the body

Answer 59

integrates with visual system to enhance a sense of equilbrium and balance

Answer 60

basically monitor movement and allow for modification specialized sensory receptors sensitive to stretch tension, adn pressure muscle spindle, Golgi tendon organs

Answer 61

receptor (interfusal fibers) in the muscle that is aligned parallel to muscle fiber (extrafusal fibers) detetcts stretch in the muscle (muscle fiber length and tension ) responsive to rate and amount of stretch stretch reflex: MS responds to stretch and sends excitatory input to the motor neuron in the spinal cord initiate an equal or stronger action to reduce this stretch casues muscle contraction inhibitory input is sent to the opposite antagonistic muslce typically counteracts movement)

Answer 62

activation of the muscle spindles relays afferet impulses through to the SC SC sends efferent impulse to cause reflex activation of the motor neurons of the stretched muscle causes muscle to shorten, reducing the stretch from the spindles

Answer 63

receptors found at the junction between tendons and muscle fibers lie parallel to muscle fiber detects difference in tension generated by active muscle responds to tension generated by: muscle contraction, passive stretch protect the muscle from excessive load if activated, GT sends impulses to elict reflex inhibition inhibits muscle contraction causing muscle relaxation good for stretching (PNF) opposite muscle is excited

Answer 64

a type of stretching where the GTO is first activated by a forceful contraction this causes aactivation of the GTO this casues activation of muscle contraction increases ability to stretch

Answer 65

at the beginning of training program, strength increases without asn increase in muscle mass increased excitability of motor neurons (easier to recruit) enhanced nerve conduction alterations in motor unit recruitment

Answer 66

the sum of unilateral strengths is greater than bilateral strength disappears with bilaterla training increases with unilateral training

Answer 67

sensory input from one limb causing inhibition on the motor neuron innervating muscle of the opposite limb possible inhibition of type ii fibers/decreased recruitment i nterference between hemisphers during bilateral contractions perceived exertion with bilaterla effort viomechanical factors (stabilization)

Answer 68

detects changes in oxygenated hemoglobin i.e indicates where there are increases or decreases in oxygen consumption in the brain gives an indication of what areas of the brain are activated and de-activated

Answer 69

a neural phenomenon the increase in strength of the untrained controlateral limb after unilateral training caused by altered nervous system activation a neuromuscular transfer effect from unilateral training to the untrained contralteral limb 52% of the strength observed in the trained limb greater efffects shown with more novel tasks have s stronger effect when dominant limb is trained and transfered to non-dominant limb because the dominant limb is more proficient at learning and mastering a task leading to better quality adaptations more room for improvement for the non dominant limb

midterm Flashcards

(95 cards)