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Exercise Physiology
Exam 2
198
Physiology
Undergraduate 2
11/04/2013

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Term
Nervous System Functions
Definition
Control of the internal environment

Voluntary control of movement

programming spinal cord reflexes

records and stores experiences (memory)
Term
Organization of Nervous system
Definition
(CNS)-Brain/spinal cord

(PNS)-sensory/motor divisions
Term
PNS (sensory division)
Definition
Afferent fibers
-receptors to CNS
Term
PNS (motor division)
Definition
Efferent fibers
-CNS to effector organs
Term
Cell body
Definition
contains the nucleus
Term
Dendrites
Definition
send impulses to cell body
Term
Axon
Definition
sends impulses away from cell body
Term
synapse
Definition
contact points between axon of one neuron and dendrites of another
Term
Multiple Sclerosis
Definition
disease that makes myelin shealths breakdown

causes motor impairment
Term
Irritability
Definition
ability to respond to a stimulus and convert it to a neural impulse
Term
Conductivity
Definition
transmission of the impulse along the axon
Term
Resting Membrane Potential
Definition
the negative charge a cell has at rest

~-75 mV
Term
Factors of RMP
Definition
permeabillity of plasma membrane to ions

difference in ion conc. across membrane
(Na,K, Cl, Ca)
Term
sodium-potassium pump
Definition
maintains RMP

K tends to leak out of cell

2K in/3 Na out

powered by ATP
Term
Action potential
Definition
occurs when a strong enough stimulus depolarizes the cell

Na channels open, Na leaks into cell (causes inside of cell to become positive)
Term
Repolarization
Definition
Cell returning to RMP

K SHOOTS out of cell
Na channels shut
Term
All or none law
Definition
Once nerve shoots, its sends signal the length of the axon
Term
Vesicles
Definition
Transport neurotransmitters in packets
Term
Synapse
Definition
Small gap between presynaptic cleft and postsynaptic cleft
Term
Neurotransmitter
Definition
Chemical messenger released from presynaptic cleft

binds to receptor and causes depolarization of postsyaptic membrane
Term
EPSP
Definition
Excitatory post synaptic potentials

Causes depolarization

-Temporal and Spatial summation
Term
Temporal summation
Definition
summing several EPSP's from one presynaptic neuron
Term
Spatial summation
Definition
Summing from several different presynaptic neurons
Term
IPSP
Definition
Inhibitory PostSynaptic Potential

causes hyperpolarization (more negative, harder to fire)
Term
Proprioceptors
Definition
Receptors that provide CNS with information about body position

Located in joints and muscles
Term
Kinesthesia
Definition
Knowing where and how fast we are moving limbs
Term
3 types of joint proprioceptors
Definition
Free nerve endings

Golgi-type receptors

Pacinian corpuscles
Term
Free nerve endings
Definition
sensitive to touch and pressure

initially strongly stimulated, then adapt
Term
Golgi-type receptors
Definition
found in ligaments and around joints

similar to free nerve endings
Term
Pacinian corpuscles
Definition
in tissues around joints

detect rate of joint rotation
Term
Muscle Proprioreceptor's function
Definition
provide sensory feedback to nervous system
Term
types of muscle receptors
Definition
Muscle spindle
Golgi tendon organ
Term
Muscle spindle
Definition
Responds to muscle length changes
Term
Intrafusal fibers
Definition
Part of muscle spindle that runs parallel to muscle fibers
Term
Gamma motor neurons
Definition
part of muscle spindle that stimulates intrafusal fibers (alpha motor neuron)
Term
Stretch reflex
Definition
a stretch on a muscle causes a reflex contraction

Ex. Knee Jerk reflex
Term
Golgi Tendon Organ (GTO)
Definition
Monitors force/tension development, prevents damage during excessive force generation

Stimulation results in muscle reflex relaxation (IPSP's to muscles)

Ability to voluntarily oppose GTO inhibition may be related to strength gains (allows muscle to push limit further)
Term
Muscle Chemoreceptors
Definition
Sensitive to changes in the chemical environment (H, K ions, CO2)

Provides CNS with info about Metabolic rate of muscle activity (needed in cardiovascular regulation)
Term
Withdrawal reflex
Definition
does not require brain receptors

reflex of muscle in response to sensory input
Term
Crossed-extensor reflex
Definition
Opposite limb supports body during withdrawal of injured limb
Term
Somatic motor division (PNS)
Definition
carries neural messages from spinal cord to skeletal muscles
Term
Motor unit
Definition
A motor neuron and all the muscle fibers it innervates
Term
Innervation ratio
Definition
Number of muscle fibers per motor neuron

Low ratio= more control

High ratio= more strength
Term
Motor unit recruitment
Definition
Recruitment of more muscle fibers through motor unit activation
Term
Size principle
Definition
Smallest motor units recruited first
Term
3 types of motor units
Definition
Type S- Slow
Type FR- Fast Fatigue resistant
Type FF- Fast, Fatigable
Term
Type S fibers
Definition
Slow type, long duration
Term
Type FR fibers
Definition
Fast, fatigue resistant type
Term
Type FF fibers
Definition
Fast, fatigable type
Term
Vestibular Apparatus
Definition
Located in ear

Maintains general equillibrium and balance (head position

Sensitive to changes in linear and angular acceleration (stimulated by head movement)

eye movement during exercise
Term
Brain Stem
Definition
many metabolic functions

cardiorespiratory control

Complex reflexes
Term
Brain Stem Structures
Definition
Medulla
Pons
Midbrain
Term
Cerebrum
Definition
Cerebral cortex and motor cortex

storage center
Term
Cerebral cortex
Definition
Organ. of complex movement

Storage of learned experiences

Reception of sensory movement
Term
Motor cortex
Definition
Motor control and voluntary movement
Term
Cerebellum
Definition
Coordination of quick movements and posture

Feedback from proprioceptors
Term
What does the Cerebellum connect to?
Definition
Motor cortex

Brainstem

Spinal cord
Term
Central fatigue
Definition
depletion of excitatory neurotransmitters in motor cortex

reduced motor output to muscle
Term
Central governor theory
Definition
brain controls fatigue levels to prevent disruption to homeostasis
Term
Spinal Cord functions
Definition
Withdrawal reflex

spinal tuning
Term
Spinal tuning
Definition
voluntary movement translated into correct muscle action
Term
What controls motor function (3)
Definition
Subcortical and cortical motivation areas

Cerebellum and basal ganglia

Motor cortex through thalamus
Term
Subcortical and cortical motivation areas
Definition
send a rough draft into movement plan
Term
Cerebellum and basal ganglia
Definition
covert rough draft into movement plan

cerebellum: fast movements

Basal ganglia: Slow, deliberate movements
Term
Motor cortex through thalmus
Definition
sends message down spinal neurons for spinal tuning to muscles

fine tuning from muscle receptors and proprioceptors
Term
ANS (Autonomic Nervous System)
Definition
Responsible for maintaining body's internal environment

2 divisions (sympathetic, parasympathetic)
Term
Sympathetic nervous system
Definition
Norepinephrine

Excites an organ
Term
Parasympathetic nervous system
Definition
Acetylcholine

Inhibits an organ
Term
How many muscles does the human body contain?
Definition
over 400

40-50% of body weight
Term
Function of skeletal muscle (3)
Definition
Force production for locomotion and breathing

Force production for postural support

Heat production during cold stress
Term
Flexors
Definition
decrease joint angle
Term
Extensors
Definition
increase joint angle
Term
Epimysuim
Definition
Surrounds entire muscle
Term
Perimysuim
Definition
Surrounds fascicles (bundles of muscle fibers)
Term
Endomysium
Definition
surrounds individual muscle fibers
Term
Basement membrane
Definition
just below endomysium (bottom layer of connective tissue covering muscle
Term
Sarcolemma
Definition
Muscle cell membrane
Term
Satellite Cells
Definition
Play role in muscle growth and repair

More nuclei allow for greater protein synthesis

Important for adaptations to strength training
Term
Myonuclear domain
Definition
cytoplasm surrounding each nucleus
Term
Myofibrils
Definition
contain contractile proteins (actin and myosin)
Term
Actin
Definition
thin filament
Term
Myosin
Definition
thick filament
Term
Parts of sarcomere (5)
Definition
z line

m line

h zone

a band

I band
Term
Sarcoplasmic reticulum
Definition
storage sites for calcium

terminal cisternae
Term
Transverse tubules
Definition
extend from sarcolemma to sarcoplasmic reticulum
Term
Neuromuscular junction
Definition
Junction between motor neuron and muscle fiber
Term
Motor end plate
Definition
pocket formed around motor neuron by sarcolemma
Term
Neuromuscular cleft
Definition
gap between neuron and muscle fiber
Term
What is released from the motor neuron to the motor end plate and why?
Definition
Ach (acetylcoline)

causes an end-plate potential (EPP)
Term
EPP
Definition
end-plate potential

causes depolarization of muscle fiber
Term
Sliding filament theory
Definition
actin moves over myosin and crossbridges deliver power stroke to shorten muscle
Term
What happens to ATP during a contraction of muscle
Definition
Myosin ATPase breakes down ATP as fiber contracts
Term
Excitation-Contraction Coupling
Definition
Depolarization of motor end plate is coupled to muscular contraction
Term
Muscle Fatigue
Definition
Decline in muscle power output (lower force generation and velocity of muscle shortening)

2 types: high intensity, low intensity
Term
High-intensity exercise muscle fatigue
Definition
about 60 secs

build-up of lactate, H+, ADP, P, and free radicals lowers amount of cross bridges that can bind to actin
Term
Long-duration exercise muscle fatigue
Definition
2-4 hours in length

Build-up of free radicals, electrolyte imbalance, and glycogen depletion
Term
Muscle cramps
Definition
Spasmodic, involuntary muscle contrations

2 theories: Electrolyte depletion and dehydration theory

Altered neuromusular control theory
Term
Electrolyte depletion and dehydration theory
Definition
water and sodium loss from sweating causes spontaneous contractions
Term
Altered neuromusular control theory
Definition
abnormal activity in muscle spindle and golgi tendon organ fires motor neurons
Term
Biochemical properties of muscle fiber types
Definition
oxidative capacity

Type of myosin ATPase
Term
Oxidative Capacity
Definition
how much oxygen the muscle can receive

effected by:

number of cailllaries, mitochondria, and amount of myoglobin
Term
Contractile properties of muscle fiber types
Definition
Maximal force production

Speed of contraction

Muscle fiber efficiency
Term
Maximal force production
Definition
force per unit of cross-sectional area
Term
Speed of contraction
Definition
(Vmax)

Myosin ATPase activity
Term
How can you type muscle fibers?
Definition
Stain them with stain that detects ATPase

Lightest uses least O2, Darkest used most O2
Term
Type I fibers
Definition
slow twitch fibers

slow-oxidative fibers
Term
Type IIa fibers
Definition
Intermediate fibers

fast-oxidative glycolytic fibers
Term
Type IIx fibers
Definition
Fast twitch fibers

fast-glycolytic fibers
Term
Non-atheltes fiber types
Definition
50-50 fast and slow twitch fibers
Term
Power athlete fiber types
Definition
Higher percentage of fast fibers
Term
Endurance athletes fiber types
Definition
Higher percentage of slow twitch fibers
Term
Isometric muscle contration
Definition
Muscle exerts force without changing length

pulling against immovable object

Postural muscles
Term
Isotonic (dynamic) muscle contraction
Definition
2 types:

Concentric

Eccentric
Term
Concentric muscle contraction
Definition
muscle shortens during force production

going against gravity
Term
Eccentric muscle contraction
Definition
Muscle produces force but length increase

going with gravity

associated with mucle fiber injury and soreness
Term
Muscle twitch
Definition
Contraction as the result of a single stimulus
Term
Latent period in muscle twitch
Definition
lasts ~5ms
Term
Contraction period in muscle twitch
Definition
Tension is developed

40 ms
Term
Relaxation period in muscle twitch
Definition
Lasts 50 ms

Release of muscle tension
Term
Why is their more speed of shortening in fast fibers?
Definition
SR releases Ca at a faster rate

Higher ATPase activity
Term
Motor unit recruitment
Definition
More motor units or faster motor units = more force
Term
Initial muscle length
Definition
ideal length for force generation

increased cross-bridge formation
Term
Sarcopenia
Definition
muscle loss from aging

10% muscle mass lost between 25-50yrs

40% lost between 50-80years
Term
What happens to muscle fiber types during aging
Definition
less fast twitch more slow twitch
Term
What can delay age-related muscle loss?
Definition
Resistance Training
Term
Cachexia
Definition
rapid loss of muscle mass

50% of cancer patients
20% of cancer deaths
Term
Muscular dystrophy
Definition
Hereditary defects in muscle protein

loss of muscle fibers and weakness
Term
Duchene muscular dystrophy
Definition
most common in childhood

progression varies based on specific disease type
Term
Force-velocity relationship
Definition
at any absolute force, speed of movement is greater in muscle with higher percent of fast-twitch fibers

Maximum velocity of shortening is greatest at the lowest force (true for fast and slow twitch)
Term
Summation
Definition
addition of muscle twitches
Term
Tetanus
Definition
individual contractions are fused in a sustained contraction
Term
Factors of force generation during muscular contraction
Definition
types and number of motor units recruited

initial muscle length

nature of motor units' neural stimulation
Term
Force-power relationship
Definition
as speed of movement increases, peak force generated decreases.

amount of power generated by a muscle group increases as a function of movement velocity
Term
Purposes of the cardiorespiratory system
Definition
transport o2 and nutrients to tissues

Removal of co2 wastes from tissues

Regulation of body temperature
Term
2 major adjustments of blood flow during exercise
Definition
Increased cardiac output

redistribution of blood flow
Term
Heart
Definition
Creates pressure to pump blood
Term
Arteries and arterioles
Definition
carry blood AWAY from heart
Term
Cappilaries
Definition
exchange of o2 co2 and nutrients with tissues
Term
Veins and venules
Definition
carry blood TO the heart
Term
Pulmonary circuit
Definition
right side of the heart

pumps deoxygenated blood to lungs and returns oxygenated blood back
Term
Systemic circuit
Definition
Left side of heart

pumps oxygenated blood throughout body

brings deoxygenated blood back to heart
Term
Layers of the heart wall
Definition
Epicardium

Myocardium

Endocardium
Term
Myocardial Infarction
Definition
Blockage in coronary blood flow results in heart muscle damage

exercise training protects against muscle and cell damage during it
Term
Exercise training and heart
Definition
Exercise is cardioprotective

less heart attacks

better survival rate during heart attacks

More capillaries means more blood can get around heart
Term
Systole
Definition
contraction phase

ejection of blood
Term
Diastole
Definition
relaxation phase

filling of blood
Term
Exercise's effects on systole and diastole
Definition
decreases the amount of time spent in phases
Term
Pressure changes in Diasole Cardiac cycle
Definition
low pressure in ventricles

allows blood to come in
Term
Pressure changes in Systole cardiac cycle
Definition
High pressure in ventricles

pushes blood out
Term
Lub (heart sounds)
Definition
Closing of AV valves
Term
Dub (heart sounds)
Definition
closing of aortic and pulmonary valves
Term
Normal blood pressure
Definition
120/80 mmHg
Term
Systolic pressure
Definition
pressure during ventricle contration
Term
Diastolic pressure
Definition
pressure during cardiac relaxation
Term
Pulse pressure
Definition
Systolic pressure - Diastolic pressure
Term
MAP (Mean Arterial Pressure)
Definition
Average pressure in the arteries

Diastolic BP + .33(Pulse Pressure)

Average is ~83 mmHg
Term
Hypertension
Definition
Blood pressure above 140/90mmHg

Risk factor for:
Left ventricular growth
atherosclerosis and heart attack
Kidney damage
stroke
Term
Factors that influence Arterial Pressure
Definition
Cardiac Output
Total Vascular resistance
Term
Cardiac Output
Definition
Output of blood per minute

Heart rate X Stroke volume
Term
Vascular Resistance (VR)
Definition
How big arteries are

effects how much blood goes through them
Term
Short term regulation of Blood Pressure
Definition
sympathetic system

Baroreceptors in aorta and carotid arteries
Term
Sympathetic nervous system effects on Blood pressure
Definition
Vasoconstriction

Increase in BP= decreased Sympathetic

Decrease in BP= increased sympathetic
Term
Long term regulation of Bloop pressure
Definition
controlled by kidneys (controls volume of blood in body)
Term
What does contraction of heart depend on
Definition
Electrical stimulation of the myocardium
Term
Conduction system in heart
Definition
SA node (sinoatrial)
AV node (atrioventricular)
Bundle Branches
Purkinje Fibers
Term
SA node
Definition
pacemaker, initiates depolarization in heart
Term
AV node
Definition
passes depolarization to ventricles

brief delay (AV delay) to allow ventricles to fill with blood
Term
Bundle branches
Definition
splits the branches of heart nerves to the left and right ventricle
Term
Purkinje fibers
Definition
superhighway of heart nerves that go throughout ventricles
Term
ECG (electrocardiogram)
Definition
Records the electrical activity of heart

indicates abnormalies to find heart disease of malfunction
Term
P wave
Definition
atrial depolarization
Term
QRS complex
Definition
Ventricle depolarization and atrial repolarization
Term
T wave
Definition
Ventricular repolarization
Term
How long is the normal heart electrical cycle?
Definition
8 seconds
Term
Myocardial Ischemia
Definition
Lack of Oxygen to heart muscle
Term
What does a ST segment depression mean?
Definition
suggests myocardial ischmemia
Term
What pressure increases during exercise?
Definition
Systolic pressure increases
Term
How can blood pressure be increased?
Definition
increase in blood volume

increase in heart rate

increase in blood viscosity

increase in stroke volume

increase in Vascular resistance
Term
Heart rate
Definition
Number of Heart beats per minute
Term
Stroke volume
Definition
amount of blood ejected per beat

regulated by:
EDV
Blood Pressure
Strength of ventricle contraction
Term
Parasympathetic nervous system
Definition
Via vagus nerve

Slows HR by inhibiting SA and AV node
Term
Sympathetic nervous system
Definition
via cardiac accelerator nerves

increases HR by stimulating SA and AV nodes
Term
Parasympathetic withdrawl
Definition
first step when heart starts to increase

raises heartbeat to ~100 beats/min

need sympathetic stimulation to get more BPM
Term
Beta-Blockers
Definition
reduce heart rate and workload on heart

decrease HR during exercise
Term
EDV (end diastolic volume)
Definition
Volume of blood in the ventricles at the end of diastole

Dependent on venous return

"pre-load"
Term
Frank-Starling mechanism
Definition
Greater EDV results in more forceful contraction

due to stretch of ventricles

"Rubber Band"
Term
What is Venous return increased by?
Definition
Vasocontriction (Sympathetic stimulation)

Respiratory pump
Term
Respiratory pump
Definition
changes in pressure in chest cavity due to volume of lungs

Increased volume of lungs= decrease in pressure
Term
What happens when venous return is increase?
Definition
Increase in stroke volume

More EDV

increase in blood volume that can push out of heart
Term
how long can stroke volume be increase?
Definition
only until heart rate is 40% of max

blood doesn't have enough time to rush in

HR must increase after
Term
What does a increase in MAP mean?
Definition
A decrease in stroke volume

An increase in "Afterload"
Term
Plasma
Definition
liquid portion of blood

contains ions, proteins, and hormones
Term
Red blood cells
Definition
contain hemoglobin to carry oxygen
Term
White Blood cells
Definition
important in preventing and fighting infection
Term
Platelets
Definition
important particles in blood for clotting
Term
Hematocrit
Definition
% of blood composed of cells
Term
Blood flow
Definition
right atrial pressure / resistance
Term
Pressure
Definition
proportional to the difference between MAP and right atrial pressure
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