Intro Biology Animal Physiology Midterm Study Questions

8/9/2019 Intro Biology Animal Physiology Midterm Study Questions

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Respiratory System:

1) What are the necessary characteristics of a respiratory surface?

High surface area, moist, thin membrane (easily permeable to gas), highly vascularized

2) Not all animals have lungs. What are other ways in which animals exchange

gasses with the environment?

Frogs can exchange gases through its skin when it isn’t using its lungs !nsects have anopen circulatory system where vessels directly come into contact with holes in the skin

called spiracles

) !e a"le to #raw a schematic of the respiratory tree an# la"el trachea$ "ronchi$

"ronchioles$ an# alveoli. %now the function of each part.

"rachea# has cartilage rings that keep tube open and allows air to flow through into the

bronchi in the lungs

$ronchi# branch into bronchioles and is a conducting pathway through which air can travelto the alveoli

%lveoli# where gas exchange occurs between air and capillaries which surround alveoli in a

web&like arrangement

&) 't sea level$ atmospheric pressure is (* mm+g. ,f oxygen were only 1*- ofthe air$ what woul# "e its partial pressure? ,f the same air were in contact with a

"eaer of "loo#$ what woul# "e the pressure of oxygen in the "loo# sample?

'artial pressure would be mmHg "he pressure of oxygen in the blood sample would bewould also be mmHg

/) Why is the 02 of alveolar air #ifferent from room air? rom exhale# air?

!n alveolar air, there is a lower '*+ because most of it has been transported into the blood

surrounding the alveoli down its concentration gradient, making it different from room airxhaled air has a higher '*+ than alveolar air does because this mixes with the air

contained in the dead space, in which there is a higher '*+ because in the dead space, no

gas exchange occurs) 3raw a #iagram showing an alveolus an# a cell of the "o#y an# the circulation

going "y each. Show the normal 02 an# 042 for each area. ,n#icate the#irection in which 2 an# 42 move at the alveolus an# at the tissue.

() What is the 2 #issociation curve for hemoglo"in 5#escri"e it in wor#s$ an# "e

a"le to #raw it)?

"he y axis label is *+ saturation in the hemoglobin, and the x&axis label is the '*+ of theblood in the tissues "his curve is a sigmoidal curve, which means that the higher the '*+ of

the blood in the tissues, the higher and steeper the saturation of hemoglobin will be -../saturation corresponds to when all 0 heme groups have an oxygen molecule bound to it

+1/ saturation 23 - oxygen molecule, 1./ saturation 23 + oxygen molecules, and 1/23 4 oxygen molecules "he affinity of hemoglobin for oxygen increases at a higher rate as



the number of oxygen molecules attached to the hemoglobin increases "his is calledcooperative binding

6) What is the "asis for the shape of the oxygen #issociation curve of

hemoglo"in?

5ee 6 "his maximizes the uptake of oxygen at alveolar levels of '*+ and the release ofoxygen at tissue levels of '*+ %t tissue levels, where '*+ would be lower, the saturation ofhemoglobin with oxygen is decreased and more oxygen will be released into the tissues !n

the alveolus, there is a high '*+, which is when the hemoglobin will take up more oxygen

molecules

7) What can shift the curve to the right or the left? Why woul# such shifts "ea#vantageous to the animal?

"he curve can be shifted by changes in pH, temperature, 7*+ levels, 8'9 levels, and

exercise % shift to the right (called a $ohr shift) is caused by increases in all theaforementioned factors "his causes the affinity of hemoglobin for oxygen to decrease,

which means that more oxygen will be released into the tissues when they need it For

example, when animals are exercising, they have a higher need for oxygen, and their bodytemperature increases and there is 7*+ build up in the tissues "hese increases intemperature and 7*+ causes hemoglobin to release more oxygen into the tissues when the

animal needs it % shift to the left is caused by a decrease in all the aforementioned factors

1*) 8xplain the three mechanisms "y which gas can "e transporte# in the "loo# ofa mammal. 9o what extent are 2 an# 42 transporte# "y each of these

mechanisms?

9as can be transported in dissolved form, in a chemically modified form, or attached to acarrier *xygen is mainly transported via a carrier, called hemoglobin, because of its poor

solubility in blood plasma and it not being able to be chemically modified 7arbon dioxide

however can be chemically modified into carbonic acid, and eventually bicarbonate ionwhich is carried in the blood plasma %lso, deoxygenated hemoglobin can carry carbon

dioxide, and the solubility of carbon dioxide in plasma is slightly better than that of oxygen5o, carbon dioxide can be transported in all three ways, whereas oxygen can really only be

transported via hemoglobin

11) 4ompare an# contrast continuous an# ti#al ventilation. What are the

a#vantages an# #isa#vantages of each? What maes avian ventilation moreefficient than ti#al ventilation?

!n continuous ventilation, there is constant uptake of oxygen from air into the blood

However, in tidal ventilation, oxygen is only exchanged during inhalation "hus, continuousventilation is more efficient in gas exchange than tidal ventilation %lso, because of the

nature of continuous ventilation, this may occur in countercurrent flow, which maximizeseven more the uptake of oxygen into the blood fficiency of gas exchange is also decreased

in tidal ventilation due to the presence of dead space, whereas in continuous ventilationthere is no dead space

12) +ow #oes a fish "enefit "y having countercurrent flow of water an# "loo#

through the gills? Woul# countercurrent flow "e possi"le in the lungs of achimpanee? ' "ir#?



7ountercurrent flow allows for an extremely efficient way to uptake oxygen from thesurrounding water "his is extremely beneficial for the fish because there is a much lower

'*+ in water than in air 7ountercurrent flow allows for there to always be a gradientbetween the blood and the water surrounding the vessels in the gills, which means that

oxygen will always be taken into the blood 7ountercurrent flow would not be possible in thelungs of a chimpanzee because the chimpanzee uses tidal ventilation, in which air is not

moving while gas exchange occurs "he anatomy of a chimpanzee does not allow forcountercurrent flow to occur 7ountercurrent flow would be possible in a bird because airmoves in one direction through the parabronchioles in the lungs of a bird However, this

does not actually occur because birds use a cross&current flow where blood vessels run

perpendicular to the parabronchioles, which is less efficient than countercurrent flow

1) !e a"le to #iagram the chemical transformations that are involve# in 42transport in the "loo#. What #o these transformations #o to the partial pressure

of 42 in the "loo#?

7*+ gets turned into carbonic acid when combined with water and in the presence ofcarbonic anhydrase 7arbonic acid then dissociates into bicarbonate ion and a proton, and

the bicarbonate ion is transported out into the blood plasma while a chloride ion is

transported into the blood cell, while the proton binds to a hemoglobin to allow for releaseof oxygen into the tissues "his lowers the partial pressure of 7*+ in the blood However,when the blood returns to the lungs, the reverse occurs, and carbonic acid is once again

formed from bicarbonate ion and a proton, which causes the uptake of oxygen byhemoglobin, and carbonic anhydrase reverts carbonic acid back to 7*+ and water "his

increases the '7*+ in the blood cell, which causes the 7*+ to move down its pressuregradient outside of the capillary

1&) What are three mechanisms "y which exercising muscle facilitates the release

of 2 from hemoglo"in?

Exercising causes an increase in the temperature of the body, which causes

a right shift, there is also increased CO2 production, which also causes aright shift. This CO2 also turns into carbonic acid when mixed with water,which decreases the pH through an increase in hydrogen ions in the blood,which also causes a right shift.

Excretory System

1. What are three functions that the i#ney performs?

xcretion of nitrogenous wastes, water balance:regulation, and regulation of blood

pressure

2. What are the osmotic pro"lems face# "y an organism living in a river$ an ocean$temperate lan#$ an# a #esert? What strategies for urine pro#uction an# salt

han#ling are use# "y organisms in these environments?

;iver# there is too much water in the environment, which could cause an imbalance in theelectrolytes of the organism "hus, the organism must excrete lots of water and accrue lots

of sodium chloride !n an ocean, there is a high sodium chloride concentration in the ocean,



and thus the organism must decrease the intake of sodium chloride while also excrete lotsof water !n temperate land, the organism needs to find sufficient amounts of water

. What is the a#vantage an# #isa#vantage to a mammal of pro#ucing 16* liters

of glomerular filtrate per #ay?

%n advantage would be that there is a very high chance that most of the toxins:wastes thatwere in the blood has been filtered out into the filtrate % disadvantage is that a large

amount of energy must be used to reabsorb all but a small amount of the things that arestill needed in the body

&. %now the parts of a nephron an# how they are arrange# in the i#ney.

9lomerulus, proximal convoluted tubule, loop of henle, distal convoluted tubule, collectingduct

/. Why woul# your i#ney nee# to mae your urine scant an# concentrate#? Whywoul# it nee# to mae your urine copious an# #ilute?

"he kidney makes the urine scant and concentrated when the body is dehydrated, whichmeans that the kidney reabsorbed back into the body most of the water that was filtered

out into the pre&urine during filtration in the glomerulus !t would make urine copious anddilute if the body was sufficiently hydrated, or overhydrated, which means it is trying to

release excess water so that the body will not suffer from water intoxication

. What is the #riving force for filtration in the glomerulus? What su"stances areinclu#e# an# exclu#e# from the filtrate?

"he driving force is hydrostatic pressure, which is increased when sphincters in the efferentcapillary tighten and constrict, in addition to the higher than normal blood volume being

directed toward the kidneys "his makes the hydrostatic pressure much higher in theglomerulus than in normal capillary beds, and osmotic pressure almost never exceeds

hydrostatic pressure, so that no substances go back into the blood from the filtrate "hesubstances that are included in the filtrate are water, amino acids, ions, protons, glucose,

nitrogenous wastes, and other toxins 5ubstances that are too large to pass through the

podocytes in the glomerulus membrane are excluded from the filtrate, and these includelarge proteins such as albumin, and possibly toxins that are too large, which then get

filtered out through the liver %dditionally, blood cells are excluded from the filtrate, and also

small molecules attached to large carriers such as hemoglobin carrying oxygen

(. What is the main function of the proximal convolute# tu"ule? +ow #oes it

accomplish this tas 5specifically$ which pumps an# transporters are involve#)?

"he proximal convoluted tubule reabsorbs <</ of the substances that the body needs to be

reabsorbed !t also controls the concentration of hydrogen ions in the filtrate and in theblood 5ubstances that need to be reabsorbed include glucose, water, and amino acids "o

reabsorb glucose and amino acids, =a> :?> %"'&ases are used to set up a concentration



gradient for sodium ions "his allows symporters in the apical membrane of the cells in theproximal convoluted tubule to transport sodium ions down its gradient into the cell %long

with the sodium ion, either a glucose or an amino acid can follow it through, andglucose:amino acid channels in the basal membrane of the cell allow for these molecules to

pass out of the proximal convoluted tubule and back into the blood stream "his higherconcentration of solutes outside of the tubule allows water to flow down its concentration

gradient through a@uaporins in the membrane of the tubule Hydrogen ions are transportedfrom the outside of the tubule against its gradient to the inside of the tubule through anantiporter that works through the concentration gradient of sodium ions created by the

sodium:potassium %"'&ase

6. What is the main function of the loop of +enle? +ow #oes its structure$selective permea"ility to water$ an# #istri"ution of so#ium pumps an#

transporters accomplish this tas?

"he loop of Henle functions to reabsorb water and sodium and chloride ions !t also sets up

a concentration gradient down the medulla such that sodium chloride concentration is higherdeeper into the medulla "he permeability of the descending limb to water and its

impermeability to sodium chloride ions allow for only water to be reabsorbed back into theblood "he permeability of the ascending limb to only sodium and chloride ions through

sodium:potassium %"'&ases creating a gradient for sodium ions to travel into membranecells through a triporter along with +7l2 and ?>, and potassium ions exit the cell through

leaky potassium channels and chloride ions exit the cell into the interstitial space through apassive chloride channel (facilitated diffusion), and its impermeability to water allows for a

sodium chloride concentration gradient to be created down the medulla, which is what thedescending limb utilizes for reabsorption of water

7. +ow is the final osmolarity of the urine regulate#? What is the ma;or hormone

involve#$ where #oes it act$ an# what is its mechanism of action?

!hen plasma osmolarity is high, this means that there is low "uid in the blood, which meansthat there is a low blood pressure. This causes secretion of #$H secreted when bloodpressure is too low, and also causes an increase in thirst. !hen #$H binds to receptors inthe membrane of the collecting duct, this causes cyclic #%& to attach a'uaporins to(esicles, which then fuse into the membranes of the cells through endocytosis. The additionof a'uaporins allows for more reabsorption of water bac) into the blood*interstitial space,and an increase in thirst means an increase in the consumption of water. These two factorsthen decrease plasma osmolarity, which corresponds to higher "uid in the blood and ano(erall increase in blood pressure. +f this osmolarity is too low, that means that bloodpressure is too high, and this causes a decrease in a'uaporin concentration in the collectingduct membrane, and a decrease in thirst, which then decreases water reabsorption through

the collecting duct, and lower consumption of water.

Circulatory System1) %now the #ifferences "etween the hearts of a fish$ frog$ an# rat.

"he heart of a fish has + chambers, a frog’s heart has 4 chambers, and a rat’s heart has 0

chambers "he fish’s + chambered heart is beneficial only for the fish because in water,

there is less gravity in water, which means the heart does not need to pump as hard toincrease pressure so that organs that are a vertical distance away from the heart can



receive blood "he organs are placed in series, which increases the resistance of the circuitAnder the pressure that the hearts of mammals may produce, the gills of the fish will most

definitely be damaged However, the buoyant environment the fish inhabits allows for alower pressure to exist in the circulatory system of the fish "he frog’s heart partially

separates the pulmonary and systemic circuits, which allows for the perfusion pressure to belower when blood is being pumped to the lungs than when the blood is being pumped to the

rest of the body !n rats, the 0&chambered heart completely separates the pulmonic andsystemic circuits, such that pressure in the pulmonic circuit is low enough so that the lungswill not be damaged, whereas pressure in the systemic circuit is high enough to pump blood

to the whole body "his is what is optimal and preferred

2) %now the flow pattern of "loo# through the human heart.

$lood goes back into the heart through the superior:inferior vena cava into the right atrium

) What is the function of the heart valves? What woul# happen if the aortic

valve #i# not close properly?

Heart valves prevent blood back flow into the atria from ventricles and into the ventricles

from the aorta:pulmonary artery !f the aortic valve did not close properly, then overallblood pressure would be decreased, because not as much blood volume is being pushed out

into the aorta through the rest of the body "his lower volume of blood in the same amountof space causes low blood pressure "his lower cardiac output is during the diastole, where

there is still blood in the ventricle

&) 4ompare an# contrast arteries an# veins. What is the main function ofcapillaries$ an# how #oes their structure reflect this function?

/) 8xplain how it is possi"le that "loo# flows more slowly through capillarieswhen these are smaller #iameter vessels.

there is a higher overall volume for the same amount of blood to travel through "hus, the

speed of blood flow through capillaries is lower "his is also advantageous as it gives moretime for exchange of gases between the blood and tissues

) Which vessels are volume reservoirs? Which are pressure reservoirs?

the volume reservoirs are the veins and the pressure reservoirs are the arteries

() 8xplain how "loo# flow can "e re#irecte# to the intestines after a meal. 9o theleg muscles #uring running. Why is it a "a# i#ea to eat a meal an# then go

running?

%fter a meal, dilation of the arterioles supplying the intestines directs blood flow to the

intestines 8uring running, dilation of arterioles supplying the leg muscles directs blood flowto the muscles %fter eating a meal, all the blood will be directed to the intestines fordigestion, and if a person begins to run, not enough blood will reach the muscles since there

will not be enough cardiac output for blood to reach both the muscles and the intestines,

which could result in cramping

6) Why woul# you #evelop e#ema 5an increase in interstital flui#) if the "loo#al"umin concentration falls? ,f you #evelop heart failure?



+f albumin concentrations in the blood are lower, then there will not be ashigh of an osmotic pressure between the interstitial space and the capillary. This means that not as much "uid will be ta)en bac) into the capillary in the(enous end of the capillary, which increases the production of lymph. +f heartfailure occurs, there will be lower cardiac output and an increase in the blood

(olume in the (eins, which increases hydrostatic pressure. This increase inhydrostatic pressure causes more "uid to be pushed out of the capillariesand into the interstitial space, which increases interstitial "uid and thus theproduction of lymph.

!hen the heart muscles contract, the signal reaches the outer membrane ofthe muscle cells, which cause the (oltage gated a- channels to open allalong the outer membrane and through the Ttubule, such that thedepolari/ation reaches the sarcoplasmic reticulum. This causes (oltage gatedCa2- channels to open and the calcium ions in the S0 will "ood the musclecell so that myosin and actin can bind together for contraction of the muscle.Howe(er, there are also 1type calcium ion channels in the membrane of themuscle cell, which also causes calcium ions in the interstitial space to "oodinto the muscle cell. This allows for the most complete contraction of themuscle, which is important in the heart. !hen the muscles relax, andrepolari/ation is occurring, all the (oltagegated channels are closed. The

calcium ions are pumped bac) into the S0, and a Ca2-*a- exchangerpumps calcium bac) out while bringing a- in. This rapidly clears thecalcium ions in the muscle cell for complete relaxation.

The drug diagoxin leads to a stronger cardiac output by lowering the actionof sodium*potassium #T&ase and Ca2-*a- exchanger. The lowering of theaction of the #T&ase reduces the steepness of the concentration gradient ofsodium ions, which slows the action of the calcium*sodium exchangerbecause sodium ions do not diuse into the cell as 'uic)ly. Thus, less calciumions are released into the en(ironment, which causes more calcium ions thannormal to be pumped into the S0. This superloads the S0 and when

depolari/ation occurs, an e(en higher amount of calcium ions "oods themuscle cell because 345 of the calcium ion concentration comes from theS0, whereas only 645 comes from the en(ironment. This gi(es a strongercontraction of the heart muscle, which leads to stronger cardiac output.

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Intro Biology Animal Physiology Midterm Study Questions