Physio exam

7/29/2019 Physio exam

http://slidepdf.com/reader/full/physio-exam 1/26

What are the 2 control systemsof the body?

nervous and endocrinesystems

2 stages of transport ofECF?

1. movement of blood incirculatory system

2. movement of fluid betweencapillaries and cells

Percentage of ICF and ECF inbody weight and total body

water?

ICF: 40% bw, 60% tbwECF:

plasma- 5% bw, 8% tbwinterstitial fluid- 15% bw, 30%

tbw

Biggest components of plasma(ions, pr)?

Sodium, chloride,some pr

Biggest componentsinterstitial? Sodium, chloride

Blue Flashcard Printing of Veterinary Physiology Questions http://www.studyblue.com/servlet/printFlashcardDeck?deckId=

6 2/1/2013



Biggest componentsintracellular?

Potassium, pr

Reason for chemical differencebetween ICF and ECF?

ICF separated by selectivelypermeable membrane, favors

diff ions

Permeability of lipidbilayer?

FA chains major barrier towater-soluble substances butallow fat- soluble substances

5 functions ofmembrane proteins?

Receptors, enzymes, ionchannels, membrane carriers,

antigens

5 ways substancescross membranes?

Endo/exocytosis, l ipid bilayer diffusion, protein

channel diffusion, facilitated diffusion, activetransport


6 2/1/2013



How does diffusionwork?

moving molec approaches station molec,transfer energy, new elastic collisions, evening

out of concentrations

5 factors affectdiffusion rate?

[ ] gradient solute, x-sectionalarea, temp (p)solute size,

viscosity of medium (i)

Movement throughprotein channels?

some molecs move thru membrane faster thansimple diffusion would explain, use protein

channels to cross

4 factors that affect rate throughpr channels?

size, charge, electrochemgradient, pressure gradient

Factors that affectosmosis?

membrane permeabilty, [ ]

gradient of solute, pressuregradient thru membrane


6 2/1/2013



Body fluid shift during waterload? Water loss?

load: decrease osmolality, increase in volumeprop to both compartmentsloss: increase

osmolality, decrease volume

Body fluid shift during soluteload? Solute loss?

load: increase osmolality, ICF expanded, ECFcontractedloss: decrease osmolality, ICF

expanded, ECF contracted

Affects chem and electricgradient on membrane

transport?

move to areas of lower [], move to areas of oppcharge, if in opp directions movement depends

on balance (electrochemical gradient)

Polarized transportepithelial cells?

Epithelial cells lining lumen and those liningbasolateral membrane have different transport

mechanisms, are energy efficient, allowunidirectional transport

What cells have rmp?All cells have rmp, only nerves

and muscles are excitable


6 2/1/2013



Equal Na & K; membranepermeable to only K, how does

membrane potential arise?

K moves down gradient, adds + to Na section,further addition prevented, electrical potential

across membrane K part more -

Equal Na & K; membranepermeable only Na, how does

mp arise?

Na moves down gradient, adds + to K section,further addition prevented, electrical potential

across membrane Na part more -

Forces acting on ions?Chemical and

electrical gradients

Eq potentials and rmp K, Na, Clin nerve?

K -94mv, Na +35mv, Cl-65mvRmp -70mv

2 functions Na/Kpump?

Maintain concentration gradient

for K and Na, stops cells fromswelling by osmosis of water


6 2/1/2013



What is the ratio of Na:K ions inthe pump? How many ions

move during 1 AP?

3 Na removed for every 2 Kpumped in.Very few (1 millionth

of available ions)

Duration of AP in nerves,skeletal m, cardiac m?

Nerve 1ms, cardiac 300ms,skeletal 1.5-2ms

Why AP does notreach Na eq potential?

Increased Na permeability lastsonly a short time & there is no

time when only Na is permeable

Add NaCl to ECF; effect onmagnitude of AP?

Increase [] gradient for Na, magnitude of AP notaffected because mp approaches Na eq in a

normal AP anyway

Mechanism thatreturns AP to rmp?

Continued increased

conductance of K when Napermeability back to normal


6 2/1/2013



How do local anesthetics block AP? Would ametabolic inhibitor affect the generation of

further APs?

Act on activation gates of Na channels bymaking it difficult to open, decreases

excitabilityAPs generated before ions breakdown enough to prevent generation

Describe voltagedependent Na

channels.

activation & inactivation gate, inactivation openat rmp, mp decreases Na rushes in, inactivation

closes slowly, open once cell at rmp

2 physiochemical disturbancesproduced by stimulationexcitable membranes?

Propagated APs and local,non-propagated potentials

(subthreshold)

Membrane disturbances causedby subthreshold stimuli?

Local, decays, not refractory(can sum), depolarizing EPSP or

hyperpolarizing IPSP

Direction current flows and whatcarries it?

Positive tonegativeIons carry it


6 2/1/2013



Describe how APpropagates?

Inside cell + at peak of AP, outside - and +current flow inside results in depolarization ofadjacent area, Na gates open, AP generated,

continues to propagate

Describe saltatory conductionand its advantages.

Myelination except at nodes focuses outwardcurrent to nodes, membrane permeability

changes only at nodes, leaps from node tonodeFaster, conserves energy, less space

2 factors affect velocityof AP?

Axon diameter (larger faster),myelination (myelinated faster)

Determines directionconduction AP?

Orthodromic movement, mpbehind AP still refractory so

moves only forward

First 3 steps of AP atNMJ?

1. AP in presynaptic MN2. Depolarization of MNterminal knobs

3. Opening of voltage-gated Ca channels inknobs


6 2/1/2013



Steps 4-6 of AP atNMJ?

4. Influx Ca down [] gradient into cell5. Achvesicles fuse to MN terminus, release Ach

6. Diffusion of Ach into cell at endplate


7. Ach attaches to receptors at end plate8.Small cation channels open at end plate

9. Influx Na into muscle at end plate


10. Depolarization of membrane at end plate(EPP)11. Generation AP across membrane to

adjacent end plate12. APs propagated along membrane, spread in

all directions from end plate

Ionic mechanisms of end platepotential (EPP)?

Ach binding to ep receptor causesconformational change allowing ions to enter.Only Na enters bc mp is close to eq p of K so

stationary to keep gradient & Ca has lessmobility

Structural componentsskeletal muscle?

Bundles of multinucleated cells, bundles ofmyofilaments (myofibrils) along long axis,

sarcomeres make up myofibrils, 2 typesmyofilament: thick and thin


6 2/1/2013





4 functions ATP inmuscle contraction?

Position myosin head & increase binding affinityfor actin, powers crossbridge movement,

release myosin head from actin, brings Ca backto SR

Grading of muscle activityaccomplished?

Varying stimulation frequency,recruitment

Briefly describe the slidingfilament theory of muscle

contraction

1) Ach released, goes through the sarcolemma& into the muscle fiber

2) Sarcoplasmic reticulum releases Ca2+,coating all of the microfibrils

3) Ca2+ bind to actin filament, causing myosinfilament to stick to actin filament

4) Myosin heads pull actin filaments together (Hzone and i band disappear)

5) Sarcomere shorten, causing muscle fiber toshorten, causing muscle to shorten

3 types tissueinnervated by ANS?

Smooth, cardiac,glands

Distinctive features ofANS?

Controls internal environ, less voluntary, doesnot initiate function just supports & regulates,

dual innervation (e, i), organs in ANS do notatrophy


26 2/1/2013



2 anatomical divisionsof ANS?

Sympathetic nervous system(SNS), parasympathetic nervous

system (PNS)

Fibers of the 2divisions of the ANS?

PNS: craniosacral, shortpost-ganglionic

SNS: thoracolumbar, shortpre-ganglionic

How are nerve impulsestransmitted pre to post in ANS?

Ach secreted by pre,synapse post

How are nerve impulsestransmitted from post to

effector?

Post releases neurotransmitter (Ach in PNS, NEin SNS) synapses with cells of effector organs

Note: SNS sometimes secrete Ach, sweatglands vasculature of skeletal muscle

Neurotransmitters for eachsynapse in ANS?

SNS: pre Ach, post NEPNS: preAch, post Ach


26 2/1/2013



Describe the synthesis andbreak down of ACh.

Synthesis happens in the nerve terminal.Choline + AcetylCoA -----> (choline

acetyltransferase) Acetylcholine + CoA

Metabolism - Acetylcholine ----> (acetylcholineesterase) Choline + acetic acid

Describe the synthesis andsecretion of acetylcholine

1. choline is transported (cotransport with Na)into cell

2. choline + acetyl-CoA converted to AChthrough choline acetyltransferase (ChAT)

3. ACh enters vesicles4. With increase in Ca, the vesicles fuse and

ACh gets secreted into the synapse5. membrane bound AChE (both presynapticnad postsynaptic) rapidly degrades ACh into

choline and acetate

What is the duration ofaction of Ach?

Few seconds

Pathway forepinephrinesynthesis?

Tyrosine ---> (Tyrosine Hydroxylase) --DOPA--->(DOPA decarboxylase)---Dopamine

---->(Dopamine Beta-Hydroxylase)---NE--->(phenylethanolamine-N-methyl-

transferase(PNMT))---Epinephrine

Describe secretion of Epi & NEby adrenal medulla.

PNMT only in adrenal medulla so secretes both

Epi and NE, stored in secretory vesicles,secreted via exocytosis


26 2/1/2013



Termination of NE action can beaffected via three mechanism:

Re-uptake of NE by active transport(up to 70%), then breakdown bypresynaptic MAO.

1.

Diffusion of NE from the synaptic cleftinto capillaries (the cleft is larger thanat endplate of skeletal muscle).

2.

Extra-neuronal uptake of NE by

COMT with subsequent intracellularbreakdown by enzymes

3.

Receptors for Achaction mediation?

nicotinic, muscarinic

Receptors for NE and Epi actionmediation?

alpha 1 (viscera), beta 1 (cardiac) --> excitatoryalpha 2 (sympathetic postganglion),beta 2

(skeletal muscle) ---> inhibitory

Effects ofparasympathetic

stimulation?

narrows pupil, decrease heart activity, dilatesarteries, increases stomach activity, stimulates

secretion of various glands

Effects of sympatheticinnervation?

increases heart activity, widens pupil, constrictsblood vessels, inhibits secretion of various

glands


26 2/1/2013



What is the significance of 300mmoles/Kg H2O?

Isotonic solution, where blood isnormally at

What are the mechanisms thatoccur during water load? Loss?

loss: increase osmolality, decrease in volume ofboth compartments

load: decrease body fluid osmolality, increase involume of both compartments

What are the mechanisms thatoccur during solute load? Loss?

load: increase osmolaloty, expansion ECF,contraction ICF

loss: decrease osmolality, ICF expanded, ECFcontracted

Net fluid movementequation?

NFM= Kf [(Pc-Pt)-(πc-πt)]

Describe voltagedependent K channels.

Activation gate on inside, mpdecreases gate opens slowly,permeability at max when Na

inactivated


26 2/1/2013



Role of circulatory system astransport system?

Transport O2 and nutrients to tissues, CO2 andwaste from tissues, reg body temp, distribute

hormones

Components of cvtransport system?

Central pump (heart), closed sysbv, fluid medium (blood)

Where does the pulmonary veincarry blood to?

Oxygenated blood intoLA, flows into LV

What happens withcontraction of LV?

Blood expelled into aorta, goesto arteries, arterioles, then

capillaries

What are capillariesresponsible for?

Exchange vessels, O2 and

nutrients pass into tissues, CO2and waste taken by blood


26 2/1/2013



Where does venous blood goafter the capillaries?

Venues to veins to RA,flows into RV

What happens withcontraction of RV?

Ejects venous blood into pulmonary artery,oxygenated blood passes thru lungs, goes to

pulmonary capillaries

What happens in the pulmonarycapillaries?

CO2 diffuses into alveoli, O2 intoblood

Describe the series circuitarrangement of the heart.

Blood flow to individual beds canbe controlled separately byartery supplying the bed.

Describe the parallel circuitarrangement of the heart.

Found in lower body, contributes

to low resistance, low pressure,organs connected in parallel


26 2/1/2013



Normal total bloodvolume in dogs?

3 to 4 L

Where is the largest part of theblood volume found?

Venous system(capacitance vessels)

What are the resistance vesselsand how much blood do they

contain?

Aterial system, 10%total blood volume

What are the exchange vesselsand what percent of bloodvolume do they contain?

Capillaries, 5% totalblood volume

What is stroke volume and howmuch is it?

Volume of blood ejected from LVby 1 beat of the heart, 70mL


26 2/1/2013



How is arterialpressure calculated?

flow (HR & SV) x resistance(caliber of small aterial vessels)

What is homeostasisfor the heart?

Stroke volume

Order the vessels in the arterialsystem from largest to smallest

lumen diameter.

aorta, arteries, arterioles,capillaries

Order the vessels in the venoussystem from largest to smallest

lumen diameter.

vena cava, veins,venules, capillaries

How does velocity change with cross-sectional

area? Which vessels have the greatest cross-sectional area?

As cross-sectional area increases, velocity

decreases. Capillaries have the greatest cross-sectional area


26 2/1/2013



Average pressure in aorta?Range & what do those

numbers mean?

100 mmHg. 80-120 mmHg, 80mmHg is diastolic pressure and120 mmHg is systolic pressure

Pressure in the arterioles?Capillaries at the start and end?

55 mmHg, 30 mmHgand 10 mmHg

Relationship between systemiccirculation pressure and vascular

resistance?

High pressure = low resistance,as resistance increases

pressure falls

Most resistance vessels & what% of resistance of system?

Arterioles, 50% of resistance ofentire system

How does elasticity change withthe different vessels?

Aorta most elastic, elasticity decreases to

capillaries, starts to increase again up to venacava (most elastic on venous side)


26 2/1/2013



Formula for resistancein circulation?

R= ΔP/Q

R= resistance, P= pressuregradient, Q= blood flow

Compare systemic circulationwith pulmonary circulation.

Systemic resistance is about 17 mmHg/min/L.Pulmonary resistance is about 1.7 mmHg/min/L

(low pressure-low resistance)

Pressures in heart chambers ofresting adult?

RA: 9/4RV: 24/4-10LV: 110/5-12

LA: 12/5

Pressures in majorvessels?

Pulmonary artery:23/16Aorta: 110/75

What is pulsepressure?

Systolic pressure -diastolic pressure


26 2/1/2013



What is mean arterialpressure?

MAP= diastolic- 1/3 pulsepressure,(Average pressure

throughout cardiac cycle)

2 major factors that affect pulsepressure?

Stroke volume output,compliance of arterial system

Increased SV affects PP how?Increased arterial compliance?

Increased SV= increasedPPIncreased compliance=

decreased PP

What body areas have thehighest blood flow distribution?

Liver, kidneys, muscle,brain

Besides muscle, why do other

areas of high blood flow requiredistribution?

Liver has to support high metabolic activity,

brain needs nutrition & prevent CO2 from bloodkidneys need for excretion


26 2/1/2013



What happens if blood flow tohigh need areas stops?

Organ failure for liver,brain, kidneys

How does blood flow differbetween inactive and active

skeletal muscle?

Inactive uses about 15% while active individualmuscle flow can increase 20-fold, total

metabolic rate 50-fold

Valves in left side ofheart?

Mitral valve (bicuspid) betweenLA and LV, aortic valve between

aorta and LV

Function of valves in left side ofheart?

Mitral valve closes during systole preventingback flow to LA. Aortic valve closes during

diastole preventing back flow to LV

Valves of right side ofheart?

Tricuspid valve between RA and

RV, pulmonic valve betweenpulmonary artery and RV


26 2/1/2013



Functions of valves on right sideof heart?

Tricuspid valve closes during systole preventingback flow to RA. Pulmonic valve closes during

diastole preventing backflow to RV

What are the atrioventricularvalves? Semilunar valves?

AV valves= mitral andtricuspidSemilunar= aortic and

pulmonic

How long doesdiastole last? Systole?

0.53 s, 0.27 s

How is a cardiac cycleinitiated?

Spontaneous generation ofaction potential SA node

What path does the AP in thecardiac cycle take?

SA node thru RA, conducted in

AV node (0.11s delay), passesto ventricles


26 2/1/2013



What does the P wave on anECG represent?

Depolarization of atria followedby atrial contractions

What does the QRS complex ofan ECG signify?

Depolarization ofventricles

What does the T wave of anECG represent?

Repolarization of theventricles

What are the major pressureelevations of the atrial pressure

curve?

a wave - caused by atrial contractionc wave -ventricles begin to contract

v wave- end of ventricular contraction

What causes the cwave?

Bulging of AV valves, pulling ofatrial muscles


26 2/1/2013



What causes the vwave?

Slow build up of blood in atriawhen AV valves are closed

How does atrial contractioncontribute to ventricular filling?

Most of the blood coming to atria can draindirectly from ventricles during diastole, about

30% comes from atrial contraction


Documents

Physio exam