Int Physio Essays

int-physio-essays

Exit

Question 1 of 1

Time Left

152576

360

block

Describe the peripheral and central neural pathways that are involved in the response to an increase in blood pressure.

Match the text (click and drag)

(0/0)

Explanation

Blood pressure is controlled through the baroreceptor reflex, a homeostatic mechanism which provides a rapid negative feedback loop. These stretch receptors are present in the aorta and carotid sinus and when blood pressure in these decreases this causes

Match the Text
1
2
3
4
5

Click and drag
Increased symp act in AutoNS, inc heart rate, force contract heart & constr arter&veins
Baroreceptors = stretch rec in aorta & carotid sinus
Bp is controlled by baroreceptor reflex, a homeostatic mech, rapid neg feedback
when BP dec, baroreceptors inhibited, decrease in AP from afferent vagus & glossopharyngeal to Solt tract nucleus (NTS)
NTS doesnt send exitation to depressor/RVLM, therefore pressor/CVLM isnt inhibited

152583

360

none

Explain the sliding filament and ratchet mechanism in skeletal muscle contraction, accounting for the role of calcium in contraction and relaxation.

Match the text (click and drag)

(0/0)

Explanation

An action potential arrives at the neuromuscular junction which causes a release of acetylcholine at the motor end plate which causes depolarisation and triggers an AP (action potential). The muscle AP travels along t tubules and opens Ca^2+ channels in t

Match the Text
1
2
3
4
5
6
7
8
9

Click and drag
act pulled past myos = shortens sarc = gen muscle force
Myos-Act bind = cross-bridge, myosin split ATP
Drags actin w/ it towards center of sarc = powerstroke
Muscle Ap travels t-tubules, opens Ca chan at SR, floods SR w/ Ca
Ca chann close& Ca pump restore low Sr in SR
SR Ca binds w/ trop-c on thin fil, shape change, expose myosin bind site
AP at NMJ, release ACh at mot end plate, causes depol, triggers AP
causes muscle relax
CausesTrop-tropomyos complex slide back on act

152592

120

none

Describe the mechanisms which cause the membrane potential changes during an action potential in the axon of a neuron (include reference to the equilibrium potential of ions across the membrane and the Goldman equation).

Match the text (click and drag)

(0/0)

Explanation

A resting potential (-65 mV) is a result of the different concentrations of Na+ and K+ ions inside and outside the cell. A Vm (membrane potential) above the threshold potential causes an influx of Na+ into the cytoplasm of the cell through a voltage depe

Match the Text
1
2
3
4
5
6

Click and drag
Memb pot (Vm) abv threshold = influx Na via ion chan = depol
Peak AP = +30 = K ion chann open, efflux to ECF = hyperpol - memb-ve than -65 = rel refrac per
Goldmans eq = equil pot accross cell memb in pres of more than 1 ion - into acc selec perm of memb
Rest pot = -65, due to conc Na and K ins/out cell
Memb +ve than -65 = abs refrac per - Na chann deact state
equil pot = Vm ions dont flow out across memb

152594

120

none

Briefly explain the concept of receptor specificity in a sensory receptor. With reference to the relative refractory period of the action potential, explain how stimulus strength is encoded in afferent axons.

Match the text (click and drag)

(0/0)

Explanation

Receptor specificity allows specialised receptors to detect specific stimuli at lower intensities. A specialised sensory receptor responds to an internal or external stimulus and initiates a graded action potential. Based on the stimulus intensity the re

Match the Text
1
2
3
4

Click and drag
spec recep responds int/ext stimuli - init graded poten
stimulus inten gener memb pot if higher than thres = AP
Recep spec = spec recep detec specific stimuli at lower intens
AP travels down affer and Ap freq DIR PROP recep pot depol

152601

360

none

An organ is able organ to maintain a constant blood flow despite reductions in perfusion pressure. This is due to flow autoregulation. Discuss the regulatory mechanisms involved in flow autoregulation. Provide a pathophysiological example of when this may occur.

Match the text (click and drag)

(0/0)

Explanation

When an organ suffers a change in blood supply resulting from a change in blood pressure, it is able to intrinsically regulate their own blood supply to a varying degree in order to meet their metabolic needs. There are various mechanisms for local regula

Match the Text
1
2
3
4
5
6
7
8
9
10

Click and drag
Tissue reoxy &vasodils washed out by blood, BF back to ctrl.
Organ change BS due to change in BP
BF falls below at dist artery as it narrows, arter resis fall - small arterie + arterio dil due to low BP - prim vess for blood flow reg
Intrin reg own BS to degree to meet metab needs
Mechan in cereb BF
react hyper = trans incr in organ BF due to breif ischaemia / arterial occul
Partial occ = signif reduc in O2 therefore mechan maintain BF even though red BP
build up vasodil metab, due to no BF = extreme autoreg - arteriole dil, leads to inc vasc resis
Mech = autoreg, react hyperaemia & endothelial
perfusion press restored=BF elavated = hyperaemia

152610

360

none

With reference to specific examples describe the roles of key cell-derived mediators in acute inflammation

Match the text (click and drag)

(0/0)

Explanation

Key cell-derived mediators are released in response to acute inflammation and are produced locally by cells at the site of inflammation. These are either intracellular granules which are rapidly secreted upon cellular activation or synthesised de novo in

Match the Text
1
2
3
4
5
6
7
8
9

Click and drag
Hist = Response tissue inj - binds recep capill/venule = vasodil & inc perm
Thromboxane A2 = vasocons, plate agg, bronchocons
PAF(plate-act fact) synth memb phospho differ path frm arach. Aggr plates also potent mediat allegric react. 100 - 1,000 more poten, induce vasodil, vasc perm
Prostaglandin D2&F2alph = bronchconst, peri vasodil, coronar vasocons, platelet agg inhib. D2 also pulmon vasocons & enh hist rel frm basoph
PhA2 acts on memb phospho - release arachidonic acid
acute infam mediat produced by local cells at site of inflamm
Metabs of Arach = Leukotriene B4 (neutro chemo & act), incr vasc perm. L C4&D4 = potent bronchoconst, vasc/art constr. LE4 = enh bronch respons, inc vasc perm
intra gran OR rapid secrete/synth de novo in response to stim
Arach = substr for cyclooxygenaseCOX & LOX

152614

360

none

Describe the mechanism of action of the Loop of Henle and the Collecting Duct to cause water reabsorption by the kidney

Match the text (click and drag)

(0/0)

Explanation

Approximately 50% of water is absorbed at the collecting duct and loop of Henlé by osmosis, this processes occurs as the loop of Henlé and collecting duct act as a single unit. There are three areas in the loop of Henlé which have different permeabilities

Match the Text
1
2
3
4
5
6
7
8
9
10

Click and drag
tubular fluid flows around LH - becomes more conc as process rep & as travels to CD
Desc lim = High H2O perm, low sol perm, H2O moves out to ECF of ren med, osmosis dwn conc grad
thin desc lim trvls toward inner med - solute conc inc, cause H2O osmosis via thin asc to ECF
Causes H2O in desc lim osmosis in ECF to equate fluid conc
Thin asc lim = Low H2O & sol perm
ATPase pump Na against conc grad into ECF - reabs Na occurs at thick asc
Countercurrent Multiplier = active trans = estab conc grad LH and ECF
LH & CD act single unit, abs 50% H2O
Thick asc limb = same as abv ALSO active Na+ reabs, Na+/K+ATPase, pump against conc grad in ECF
3 areas LH = diff perm H2O

152619

360

none

Explain how oxygen and carbon dioxide are carried by the blood.

Match the text (click and drag)

(0/0)

Explanation

Oxygen is transported in the blood through 2 main mechanisms. The minor of these two is the concentration of dissolved oxygen in the blood which is directly proportional to the partial pressure of oxygen in the gas which is in contact with the blood (0.3

Match the Text
1
2
3
4
5
6
7
8
9
10
11

Click and drag
O2 trans in blood 2 mechan
Has high aff for O2, 4 O2 per Hb
1) Henrys law = conc of O2 diss in blood DIR PROP part press O2 gas in contact w/ blood - 0.3 ml O2 / 100 ml blood
Hb= major comp blood, 2 alph, 2 beta globulin bound to iron porphrin ring
Carb acid dissoc = H+ + HCO3-
Allosteric inhib, when 1 lig binds dec affin for subst at other bind sites
60% CO2 carried by blood as HCO3-
Bicarb diss in plasma from rbc
30% CO2 transp in blood CarboaminoHb - CO2 combines w/ term amine Hb
formedin rbc as diss CO2 catyl by Carb Anhyd with H2O produce H2CO3
CO2 more sol than O2 = 10% diss in blood

Int Physio Essays

Question 1 of 1

Time Left

Describe the peripheral and central neural pathways that are involved in the response to an increase in blood pressure.

Match the text (click and drag)

(0/0)

Explanation

1

2

3

4

5

Increased symp act in AutoNS, inc heart rate, force contract heart & constr arter&veins

Baroreceptors = stretch rec in aorta & carotid sinus

Bp is controlled by baroreceptor reflex, a homeostatic mech, rapid neg feedback

when BP dec, baroreceptors inhibited, decrease in AP from afferent vagus & glossopharyngeal to Solt tract nucleus (NTS)

NTS doesnt send exitation to depressor/RVLM, therefore pressor/CVLM isnt inhibited

Explain the sliding filament and ratchet mechanism in skeletal muscle contraction, accounting for the role of calcium in contraction and relaxation.

Match the text (click and drag)

(0/0)

Explanation

1

2

3

4

5

6

7

8

9

act pulled past myos = shortens sarc = gen muscle force

Myos-Act bind = cross-bridge, myosin split ATP

Drags actin w/ it towards center of sarc = powerstroke

Muscle Ap travels t-tubules, opens Ca chan at SR, floods SR w/ Ca

Ca chann close& Ca pump restore low Sr in SR

SR Ca binds w/ trop-c on thin fil, shape change, expose myosin bind site

AP at NMJ, release ACh at mot end plate, causes depol, triggers AP

causes muscle relax

CausesTrop-tropomyos complex slide back on act

Describe the mechanisms which cause the membrane potential changes during an action potential in the axon of a neuron (include reference to the equilibrium potential of ions across the membrane and the Goldman equation).

Match the text (click and drag)

(0/0)

Explanation

1

2

3

4

5

6

Memb pot (Vm) abv threshold = influx Na via ion chan = depol

Peak AP = +30 = K ion chann open, efflux to ECF = hyperpol - memb-ve than -65 = rel refrac per

Goldmans eq = equil pot accross cell memb in pres of more than 1 ion - into acc selec perm of memb

Rest pot = -65, due to conc Na and K ins/out cell

Memb +ve than -65 = abs refrac per - Na chann deact state

equil pot = Vm ions dont flow out across memb

Briefly explain the concept of receptor specificity in a sensory receptor. With reference to the relative refractory period of the action potential, explain how stimulus strength is encoded in afferent axons.

Match the text (click and drag)

(0/0)

Explanation

1

2

3

4

spec recep responds int/ext stimuli - init graded poten

stimulus inten gener memb pot if higher than thres = AP

Recep spec = spec recep detec specific stimuli at lower intens

AP travels down affer and Ap freq DIR PROP recep pot depol

An organ is able organ to maintain a constant blood flow despite reductions in perfusion pressure. This is due to flow autoregulation. Discuss the regulatory mechanisms involved in flow autoregulation. Provide a pathophysiological example of when this may occur.

Match the text (click and drag)

(0/0)

Explanation

1

2

3

4

5

6

7

8

9