Biology 2672a: Comparative Animal

Physiology

Final review lecture

The Final Exam9 am December 8th

Talbot Hall Gym2 hours If you are sick (etc)

Take documentation to the Dean’s counsellors – they will contact me.

If in doubt, sit the exam then see the Dr.

The Final Exam73 QuestionsCovers everything from Lecture 2

(Krogh Principle etc) to Lecture 24 (Diving mammals) Including animal ethics, freezing

frogs, hibernation, migration and bird song

Includes labs (c. 3-5 questions) No overt weighting on any part of the

course

The final exam~40 simple definition-type

questions~10 harder single-part questions5 fun graph questions (multiple

parts)

The Make-up7 pm (in the evening!)Monday 12 JanuaryWill include written answers, as

per the course outline Format will be sent in advance to

those writing the make-up If you can’t do the make-up, the

next exam will be in December 2009

How your mark is calculatedAdded up (by the computer) and

rounded to the nearest integerNearest integer to (e.g.) 69.45 is

69 (sorry) I DO give 89, 79, 69 I DON’T give marks for arbitrary

reasons (so please don’t ask)

Important things to rememberREAD THE QUESTION!READ THE ANSWER!LOOK AT THE GRAPH! Just because something sounds

the most scientific doesn’t mean it is true I’m very good at generating

meaningless jargon!

TodayFive topics

Control of vasomotor tone Freshwater/saltwater fish Malpighian tubules Concentrating urine Freezing frogs

Regulation of circulation

Change Energy input

Q = ΔPπr4

8Lη

Change tube diameter

Local controlMyogenic stretch responseParacrine control

e.g. release of NO Responses to local conditions and

traumaEvents in muscle cell

viagra example

Central controlEndocrine (Hormonal)

e.g. Adrenaline (Epinephrine) Response depends on receptor densities, so same

hormone has different effects through body

Also vasopressin and angiotensinNeural

Sympathetic nervous system Usually chemically mediated.

From Fall 2007 Final ExamThe release of Epinephrine by

the adrenal glands is an example of paracrine control of vasomotor tonea) Trueb) False

The situation for a marine teleost

Chloride cellsWater

Blood

Apical(Mucosa)

Baso-lateral(serosa)

Pavement cell

Lots of mitochondria

Fig. 26.6

Export of Chloride is driven by a Na+ gradient

Box 26.2

Na+ actively pumped out of cell by Na+,K+-ATPasePotassium remains at equilibrium because of K+ channels back into blood

Active removal of Cl- leads to an electrochemical imbalance that drives Na+ out of blood via paracellular channels

Box 26.2

Chloride cell summaryTranscellular transport of Cl-

Driven by Na+,K+-ATPase (requires energy)

Paracellular transport of Na+

Ionoregulation accounts for ~3-5% of resting MR in marine teleosts

Salt Water Fresh Water

Drinking Lots

Urine Little, concentrated

Ion flux Passive into fish; active out of fish

Na+,K+-ATPase Na+ into bloodstream

Tight junctions No

Cl- Transcellular transport driven by Na+ gradient

Na+ Paracellular driven by electochemical gradient

The situation for a freshwater teleost

Fig. 26.7a

Na+ uptake

Box 3.1 Fig.A(2)Note tight junction

Cl- uptake

NaCl uptake summaryExchange for CO2

Na+ via electrochemical gradient Cl- via HCO3

- antiport

Very dilute urine gets rid of excess water without losing too much salt

Salt Water Fresh Water

Drinking Lots Little

Urine Little, concentrated Copious, dilute

Ion flux Passive into fish; active out of fish

Passive out of fish, active into fish

Na+,K+-ATPase Na+ into bloodstream

Na+ into bloodstream

Tight junctions No Yes

Cl- Transcellular transport driven by Na+ gradient

Transcellular via HCO3- antiporter (driven by H+ pump)

Na+ Paracellular driven by electochemical gradient

Transcellular driven by electrochemical gradient (set up by H+ pump and Na+,K+-ATPase)

From Final Exam, Fall 2007 In gills of a freshwater-acclimated

fish, where is the Na+,K+-ATPase pumping Na+ ions?

a) From the chloride cell into the bloodstream.

b) From the chloride cell into the surrounding water.

c) From the bloodstream into the chloride cell.d) From the surrounding water into the

chloride cell.e) From the surrounding water into the

bloodstream.

From final exam, Fall 2007 As well as an increase in Na+,K+-ATPase

activity, what else would you expect to happen as a fish moves from fresh to salt water?

a) The closure of gap junctions between pavement cells.

b) Increased activity of the Cl-/HCO3- antiporter in chloride cells.

c) Expression of chloride channels on the apical (mucosal) surface of the chloride cells.

d) Removal of K+ channels from the basal (serosal) surface of the chloride cells.

e) Increase in gill surface area.

Fig 27.21

Haemolymph

Lumen

Cells

Malpighian tubules

Haemolymph

Lumen

Stellate cellPrincipal cell

Mitochondria packed intoevaginations

Haemolymph

K+ Channel

Proton pump generates electrochemical gradient Requires ATP

K+ follows via electrogenic transporter

Lumen

V-ATPase (H+ pump)

Haemolymph

Cl- Channel

Lumen

V-ATPase (H+ pump)

Cl- follows K+ gradient

Water follows osmotic gradient into tubule lumen

Aquaporin

Malpighian tubules summary Active transport sets up ion gradients

Proton pump; K+, Cl- Water follows Passive transport of nitrogenous

wastes, amino acids etc. down electrochemical gradients

Active transport of large molecules Alkaloids, proteins etc.

Water and solute reabsorptionUrine from tubules is dilute and

contains lots of things the insect doesn’t want to lose

Reabsorption of water and solutes in hindgut/rectum Determines final concentration of

the urine

Final exam, Fall 2007Chloride ions pass from the

haemolymph to the lumen of the Malpighian tubule largely via the Principal cells.a) True.b) False.

New Question Chloride concentrations are high in the

lumen of the Malpighian tubule because...a) Active transport of chloride ions from the

haemocoel by the stellate cells.b) The chloride ions follow an electrochemical

gradient set up by sodium pumping in the principal cells.

c) The chloride ions follow an electrochemical gradient set up by proton pumping in the Principal cells.

d) All of the above.e) None of the above.

Concentrating Urine

Bowman’s capsuleUltrafiltration,Production of primary urine

Loop of Henle

Thick segment of descending loop of Henle

Re-absorption of sugars, amino acids, water

Thin segment of descending loop of Henle

Thick ascending loop of Henle

Thin ascending loop of Henle

Collecting DuctUrine out, concentration of definitive Urine

Salt Re-absorption

Fig. 27.6

Concentration gradient in kidney

Fig. 27.13

Concentration of urine Occurs in collecting

ducts Driven by osmotic

gradient across kidney

Both urea and salts Can be

manipulated by altering permeability of collecting duct to water

Fig. 27.14a

Changing concentration of definitive urine

Fig. 27.14

Medullary thickness is positively correlated to maximum urine concentration

Fig. 27.8

Concentrating UrineBigger concentration gradient =

higher maximum concentration of urine

Longer loop of Henle (i.e.: relatively thicker medulla) = longer concentration gradient = higher maximum concentration of urine

Modulating urine concentrationModulate permeability of

collecting duct to water Permeable

Concentrated urine Antidiuresis

Impermeable Dilute urine Diuresis

Final exam Fall 2007A longer loop of henle allows for

a shorter concentration gradient, increasing kidney tubule efficiency.a) True.b) False.

Final Exam, Winter 2007 Which change is primarily responsible

for the shift in production from concentrated to dilute urine?a) Increased absorption of amino acids by

the descending loop of Henle.b) Decreased absorption of amino acids in

the descending loop of Henle.c) Increased permeability of the collecting

duct.d) Decreased permeability of the collecting

duct.

To freeze a frog…Freezing initiated

Massive conversion of glycogen to glucose (liver) and circulation around body (Glycogen phosphorylase)

Dehydration of major organs (water relocated to the coelom and lymph system)

• Protein Synthesis slows to 1% • Pumps & channels closed • Energy Production slows to 5% • Energy Utilization slows to 2%• Few ‘SAP’ kinases activated • Gene ‘inactivation’ (mRNA)• Few Genes activated

• NRF-2 (= more antioxidants, especially GST)

New QuestionFreezing in frogs results in

decreased production of NRF-2 and subsequent gene activation.a) True.b) False.