Final_add ons

Question 1

Normal cell function requires stable volume-

Answer 1

composition of ICF

Question 2

Regulating ECF is the best way to prevent changes to

Answer 2

ICF

-requires integration of many organ system

-Na+ and Cl- most important

Question 3

In order for cells to function normally, first key is ensuring

Answer 3

ICF is constant and stable, volume and composition isn’t changing

Question 4

ECF composed of-

Answer 4

interstitial fluid, and plasma

Question 5

If volume of ICF starts to change, very bad why

Answer 5

causes stress on cell membrane, can affect selective permeability, can cause explosion of cell

-If volume of ICF too low shrink cell, very bad also

-Important for action potentials in skeletal muscle, neurons, and cardiac muscle

-concentration changes can fuck with all of these

Question 6

Vital for cells to have ECF staying constant why

Answer 6

-ICF will be changed by ECF

Question 7

Cells have selectively permeable membranes, changes in ECF cells can alter protein transport and stuff

Answer 7

-not very effective bc that ability is limited, only so many adjustments to make to permeability

-Better approach is to deal with ECF changes before changes ICF

Question 8

ECF dependent on many factors- what’re the smaller factors?

Answer 8

-metabolic production of certain things and consumption of certain substances, metabolism changes composition

-storage mechanisms (bones with Ca2+) as things are added or removed can affect ECF

Question 9

ECF dependent on many factors- what’re the main/big factors?

Answer 9

-Biggest things that impact involve exchange with what’s inside the body vs outside the body

-digestive tract, respiratory surfaces, and excretory surfaces

-we’re talk mostly about excretory but some others play a role in this as well

Question 10

Excretion in fish-
Teleosts (bony fish)

Answer 10

Are ammonotelic-

-Ammonia excreted via the gills

Question 11

Elasmobranchs (cartilaginous fish)

Answer 11

are ureotelic
-urea retained mostly

Question 12

Excretion in fish- nephrons

Answer 12

Nephrons mainly used for water/salt balance-

-no loops of Henle

-Can’t produce hyperosmotic urine
Loop of Henle is countercurrent multiplayer, maintains osmotic gradient throughout medulla, so impacts how concentrated urine can become, allows mammals to produce very concentrated urine

Question 13

Terms to describe relative overall concentration of fluid compared to some other fluid:

Answer 13

Isosmotic- same concentration as fluid of comparison

Hypoosmotic- below or less than concentration

Hyperosmotic- more than, above concentration

We’ll be talking about body fluid relative to surrounding water

We’ll also talk about concentration of the urine relative to the body fluids

Question 14

Fish can’t make urine more concentrated than their

Answer 14

body fluid like birds and mammals

Question 15

Teleost fish- water challenges

Answer 15

Water- (thought to have evolved in freshwater)

Teleosts are hyperosmotic to freshwater

-gain water via osmosis

Question 16

Teleost fish- water challenges

Answer 16

-Body fluids relative to freshwater are hyperosmotic

-main route of entry is the gills (downside of gas exchange surfaces in environment, site of exchange for respiratory gases and other things

-main site of osmosis gills, skin can also

Question 17

Teleost fish- salt challenges

Answer 17

-Freshwater doesn’t have many ions

-lose salts via diffusion from gills and a little bit the skin

Question 18

Teleost adaptations for water balance- (freshwater fish)

Answer 18

-blood is less concentrated than saltwater fish, this decreases the osmotic pressure so a little less water will be absorbed

-no need to drink water, will still inject water through digestive tract but not gonna start chuggin’

-produce high volume of hypoosmotic urine- good bc getting rid of lotta water being absorbed, and does so without getting rid of a lot of salt

Question 19

Adaptations for salt balance- (freshwater fish)

Answer 19

Gills have low permeability to ions

-reduces salt loss by diffusion

Epithelial cells in gills have low permeability to salt, aren’t a lot of sodium or chloride channels that favor diffusion, low permeability for salts

-instead see system of transporter that actively absorb salts across the gills

-high capacity to bring salts in

Question 20

Teleost fish (freshwater) – adaptations for salt balance

Answer 20

Gills have low permeability to ions
-Reduces salt loss by diffusion

Na and Cl are absorbed across the gills-
Na+ in exchange for H+/NH4+

Cl- in exchange for HCO3-
Na+ and Cl- in water, need to get into the blood.

Question 21

There are 4 transporters that facilitate all this movement:

Answer 21

-first is antiporter for Na+ and H+ ions or NH4+ ions

-sodium will come into epithelial cells in exchange for H+ ions or NH4+ ions

-kicking out ammonia and bringing it sodium

Question 22

the other 2:

Answer 22

-Cl- comes in through different transporter that brings Cl- in in exchange for HCO3- (coming from the blood, it’s a buffer for CO2 transport) how fish get rid of CO2

-Cl- have chloride channels, comes into cell then diffuse out

-Na+ just have sodium-potassium pump which pushes it out of epithelial cells in gills to body, K+ goes in as Na+ is pumped out

Question 23

Life in Saltwater-
Teleost’s-

Answer 23

Water-
-teleost’s are hypoosmotic to seawater
-lose water by osmosis

Salts-
-gain salts by diffusion and diet

Question 24

Adaptations for water balance-
(saltwater)

Answer 24

-blood is more concentrated than freshwater fish

-low volume of isosmotic urine (more about salt and water balance than excretion of metabolic waste products) cant be hyperosmotic, probably bc evolved in freshwater

-water is gained by drinking (but co are Na+ and Cl-) these fish will drink

Question 25

Teleost fish – adaptations for salt balance (saltwater fishes)

Answer 25

Can only produce isosmotic urine, so can’t eliminate enough Na+ & Cl- that way Na+ & Cl- are eliminated across gills NKCC cotransporters

Question 26

Adaptations for salt balance- (saltwater fishes)

Answer 26

-Can only produce isosmotic urine so cant eliminate enough Na+ and Cl- that way -Na+ and Cl- are eliminated across gills NKCC cotransporters Sodium, potassium, and 2 Chloride ions -In the middle we’re gonna have our NKCC in epithelial gill cells, 4 ions moving through all in same direction -Cl- on other side of membrane we have chloride channels -Have sodium getting kicked out of cell through sodium potassium pump, so K+ then pumps in -Potassium channels to get them out -Na+ goes in between cells?? -getting Cl- out moving negative charge into water, so Na+ will be pulled from blood through gaps of epithelial gill cells into surrounding water

Question 27

What ions do NKCC cotransporters move?

Answer 27

Sodium, potassium, and 2 Chloride ions

Question 28

Freshwater fishes-

Answer 28

-tight junctions between body bc body fluids saltier than the water, gills less permeable to that diffusion -tight junctions seal gaps between epithelial cells of the gills to try and prevent Na and Cl- from leaking out

Question 29

Saltwater fishes-

Answer 29

hypoosmotic, losing water to environment -drink salt water, produce very little urine -need to be pumping salt out of the blood -NKCC cotransporters on side of membrane facing the blood, transport Na+ K+ and 2 Cl- into the cell -NaK+ pump pumping sodium back out of cell, and potassium channels that allow K+ to come into the cell and go back out -Cl- channels on other side so Cl- that’s coming in can go back -not way to get rid of Na+ ions, they’ll leave through gaps in epithelial cells -active pumping of Cl- out creates a but of an electrical potential which will favor the movement of these Na+ ions out

Question 30

Elasmobranchs- Challenges (primarily in salt water) Water-

Answer 30

Are isosmotic or slightly hyperosmotic to the seawater, body fluids much more concentrated than saltwater teleost’s, no huge osmotic gradient, water retention/loss not an issue -retain urea and TMAO (why their body fluids are so concentrated) -TMAO is trimethylaminooxide, byproduct derived from trimethylamine, gas that produces that fishy odor, derived from ammonia

Question 31

Elasmobranchs- Challenges (primarily in salt water) Water-

Answer 31

Urea- Denatures proteins -solving osmotic difference but causes a different problem Salts- Primarily gained through diet, not much drinking

Question 32

Adaptations- (elasmobranchs)

Answer 32

-water balance maintained by urine production -Urea-resistant protein isoforms & stabilization by TMAO -Shark proteins without TMAO will be messed up with urea

Question 33

How are salts excreted in elasmobranchs?

Answer 33

Salts excreted by rectal gland- mechanism similar to marine teleost gills (loaded with NKCC cotransporters, which results in concentrated salty fluid they can then release to surrounding water)

Question 34

Birds & Reptiles- similar challenges to marine teleosts

Answer 34

-hypoosmotic to seawater, so lose water through osmosis -mainly gain salts through diet -drinking of seawater highly variable, birds wont some reptiles way depending on their capacity to get rid of excess salts

Question 35

Adaptations- (birds and reptiles)

Answer 35

-Integument is relatively impermeable to water and salts -reptiles drink seawater to maintain fluid balance -excrete salts via salt glands Salt glands- usually in head area -produce concentrated salt solution via mechanisms similar to marine teleost gills and elasmobranch rectal glands (NKCC cotransporters) -release via ducts near eyes or nostrils

Question 36

Marine mammals- (in saltwater)

Answer 36

Hypoosmotic to seawater -little transport across integument -mainly gain salts and water through diet (if they cant drink freshwahter, water intake through food as well) -hyperosmotic urine (reptiles can’t do this hence need salt glands) -bc of loops of henle and nephrons -some will migrate back forth between fresh and salt water

Question 37

Teleosts Changing Salinities Anadromous:

Answer 37

Anadromous: from saltwater to freshwater (example salmon) -high volume of hypoosmotic urine (increase urine production and dilute depending on environment) -little drinking (switch drinking style) -gill transporters switch to freshwater state (in saltwater NKCC transporters, when move to freshwater switch and permeability of gills change (junctions between epithelial cells)

Question 38

Teleosts Changing Salinities Catadromous:

Answer 38

Catadromous: from freshwater to saltwater -low volume of isosmotic urine -increased drinking -gill transporters switch to marine state (switch to NKCC)

Question 39

Elasmobranchs-

Answer 39

-Mainly marine, some migrate to freshwater (stingrays and bull sharks) Changes when migrating to freshwater -less urea produced and retained -more urine produced -decreased salt excretion by rectal glands -increased salt uptake by gills

Question 40

Life on land- (salt balance less of a concern, water balance a huge concern)

Answer 40

Hydric- have the most water, humid like marshes/swamps etc Mesic- forested areas, not super dry or wet Xeric- very dry, desert, alpine, areas without much water vapor in the air (challenges of water loss highest here)

Question 41

Life on land- main causes of water loss

Answer 41

-evaporation -urine -feces Evaporation and urine will have most variation/adaptations

Question 42

Inspired air gets warmed and humidified as it passes through turbinates and respiratory tree (warming facilities gas exchange)

Answer 42

-any water not recovered during expiration represents evaporative loss -as air flows through nasal cavity picks up lot of water vapor in turbinates, and warms up to match the body temperature to maximize gas exchange, most of the warming happens in the turbinates -water not recovered is lost -during expiration trying to keep as much water as possible, and water cools as it leaves -water content higher in expired air than inhaled, but lower than in lungs

Question 43

Primary routes of evaporative water loss-

Answer 43

-respiratory system -integument Rate increases as body size decreases- -surface area: volume ratio, as animals get smaller higher rate of evaporative loss and higher metabolic rate -metabolic rate

Question 44

Recovering water-

Answer 44

-warming inspired air cools the turbinates -water condenses as expired air passes through the now cooler turbinates so water re-condenses and leaving air cools

Question 45

Maximizing water recovery-

Answer 45

The more extensive coiled and extensive turbinates are, the more they’ll cooled off so the more water condensation they’ll cause -coiling of turbines increase air cooling and condensation -ours are pretty meh, seals and camels have great ones

Question 46

Challenges-

Answer 46

-rate of water loss increases with metabolic rate (endotherms consistent so not a huge deal) -but ectotherms: metabolic rate increases w/temperature -many reduce metabolic rate during hottest months Chuckwallas masters of this

Question 47

Hot environments- Temps go up, water becomes harder and harder to find Cutaneous evaporation- Reptiles, birds and mammals-

Answer 47

-epidermis has layers of dead cells and lipids that limits evaporation Can probably adjust thickness and composition as humidity levels change -reptiles susceptible to dehydration during molting In these groups it isn’t too big of a concern, huge concern to amphibians

Question 48

Amphibians-

Answer 48

-mucus glands keep skin moist, but represent a major source of water loss -most live in ponds so not a problem

Question 49

Tree frogs- (not more exposed bc not in water source)

Answer 49

-waxy secretions in additional to mucus they rub all over themselves, and assume a tucked down body position reducing the surface area being exposed to the air

Question 50

Desert frogs-

Answer 50

-come out and reproduce when water, but otherwise metabolic rate drops and they stay covered in a burrow -aestivate in burrows -form a cocoon of skin and lipids -absorb water from urine in bladder

Question 51

Water loss through feces is largely fixed, Water loss through urine is

Answer 51

variable

Question 52

Amphibians and Reptiles-

Answer 52

-nephrons lack loops of Henle so urine is isosmotic (most animals have non-mammalian kidneys like this) -Lower GFR to reduce urine volume when dehydrated (they have a much greater capacity for GFR variation) -Reptiles excrete uric acid -lowers filtrate osmolarity -more water reabsorbed at nephrons

Question 53

Birds- kinda intermediate

Answer 53

-mix of nephrons with and without loops of Henle -can produce moderately hyperosmotic urine -mix in their kidney -Excrete uric acid, doesn’t require much water, semi solid waste product -Reabsorb water from urine stored in coprodeum (part of cloaca where kidneys and digestive tract draining into, and reproductive structures) -where urine is going into, can extract additional water from coprodeum same as toads

Question 54

Mammals-

Answer 54

-All nephrons have loops of Henle -cortical vs juxtamedullary -Can produce highly hyperosmotic urine -concentration varies with hydration levels

Question 55

What species produce most concentrated species

Answer 55

Xeric

Question 56

Variability across mammals in how concentrated they make the urine based on

Answer 56

How long the loops of Henle are, and relative medullary area (RMA) -RMA gross anatomical difference, how much is cortex vs medulla, more medulla more vertical osmotic gradient

Question 57

Life with Low Oxygen-

Answer 57

-Low oxygen environments/situations- -water -high elevation/altitude -subterranean environments -diving by air breathers -Others (high metabolic rate, disorders, etc)

Question 58

Fundamental considerations-

Answer 58

Hypoxia vs anoxia Hypoxia often coupled with hypercapnia (increased CO2), especially in subterranean environments and pH changes with low oxygen, might have more CO2 disrupting acid base balance -Adaptations involve respiratory and/or cardiovascular systems -Many animals will also decrease body temp

Question 59

Main adaptations-

Answer 59

-increased ventilation rate -lower metabolic rate -increased gill surface area -hemoglobin: increased concentration and affinity for O2

Question 60

Oxyregulators vs oxyconformers

Answer 60

-further from surface of water less oxygen and less plant life so oxygen drops again -decomposition done by bacs monch the O2 as well -lotta possible variation in water -fish gonna be exposed to different oxygen levels more often -can be changes to affinity of hemoglobin for oxygen -fishes are oxyregulators or oxyconformers

Question 61

Most vertebrates not sensitive to changes in

Answer 61

O2, CO2 will be more noticeable, in fish O2 levels very noticed and sensitive

Question 62

Oxyregulators vs oxyconformers

Answer 62

-further from surface of water less oxygen and less plant life so oxygen drops again -decomposition done by bacs monch the O2 as well -lotta possible variation in water -most vertebrates not sensitive to changes in O2, CO2 will be more noticeable, in fish O2 levels very noticed and sensitive -fish gonna be exposed to different oxygen levels more often -can be changes to affinity of hemoglobin for oxygen -fishes are oxyregulators or oxyconformers

Question 63

Oxyregulator vs oxyconformer

Answer 63

Oxyregulator- they can maintain a more consistent level of PO2 within the blood Oxyconformer- cannot maintain consistent blood PO2, so PO2 will change much more as oxygen in water changes

Question 64

What determines if a fish will be an oxyregulator or oxyconformer?

Answer 64

based on how stable oxygen levels are wherever they evolved

Question 65

-Crucian carp-

Answer 65

-gills have feathery filaments, sticking off each is protrusions of lamellae -in these carp they have a change in gill structure in low oxygen -after a week in hypoxic conditions lamellae show up, cells shrink in between lamellae to expose them

Question 66

Main adaptations

Answer 66

-Hyperventilation (Doesn’t lead to decreased respiratory drive and reduced cerebral blood flow as it does in mammals) -Larger tidal volume, increased pulmonary surface area, reduced diffusion distance

Question 67

High altitude flight- Main adaptations:

Answer 67

cold temps, decreased air temps, lotta challenges Hyperventilation- doesn’t lead to decreased respiratory drive and reduced cerebral blood flow as it does in mammals -If CO2 levels drop respiration rate tends to slow in mammals, but don’t see that in high altitude birds -common for cerebral blood flow to decrease in mammals as CO2 levels drop which causes vasoconstriction of vessels within the brain (not great)

Question 68

High altitude flight- Main adaptations:

Answer 68

-Larger tidal volume, increased pulmonary surface area (of the lungs,) reduced diffusion distance (which means that if you’re lookin at an airway and a capillary the diffusion distance is the distance that oxygen has to travel to get from the air into the blood) Various things can determine this -birds don’t have that cerebral blood flow decrease with low CO2 response Larger hearts, higher stroke volume, greater cardiac capillarization (more capillaries to heart) -no pulmonary hypertension/edema (pretty common in animals at high elevations)

Question 69

Edema-

Answer 69

build up of interstitial fluid, within the lungs very bad bc fluid building up between capillaries and gas exchange surfaces can lead to lungs filling with fluid (maladaptive response) the thought is that in normal healthy lungs damaged alveoli may have pulmonary vessels not having gas exchange, those vessels will then constrict so blood goes where needed. At high elevation entire lungs are hit with hypoxia, widespread vaso-constriction which then increases amount of interstitial fluid up and out of capillaries -fluid gonna increase diffusion difference so less oxy makin it to blood

Question 70

Bar-headed geese-

Answer 70

fly over the Himalayas!! Highest flying geese -Higher ventilation volume and PO2 of arterial blood -Hemoglobin has increased affinity for O2 -Increased capillarization of flight muscles -Higher temps of flight muscles

Question 71

Subterranean living-

Answer 71

-Main adaptations- -Reduced sensitivity to high CO2 levels -hemoglobin has a higher affinity for O2 in mammals, but not birds -Lower basal metabolic rates

Question 72

Cave fish- lots of unique adaptations

Answer 72

-enhanced lateral line system to detect water motion, as swimming water flow across body in certain pattern so they can detect what’s around them For low O2- -Higher hemoglobin concentrations in the blood -higher hematocrit levels (% of blood that is made up of red blood cells) -humans 45%, fishes around 30% but blind had higher than surface fish -similar red blood cell counts between blind cave fish and surface fish

Question 73

Naked mole rats-

Answer 73

-mole rats are eusocial, strangely long-lived for decades -highly resistant to cancer, monch toxic tubers, can knock back pain detection -seal burrows to prevent snake, CO2 gets elevated, low O2 levels -can survive without O2 for 18 minutes -Reduced heart rate, metabolic rate, and brain activity -normal heartrate around 200BPM

Question 74

Naked mole rats-

Answer 74

-Can survive 18 minutes without O2! -Reduced heart rate, metabolic rate, and brain activity -Brain slices recover function after anoxia -Elevated hypoxia inducible factor (HIF) -Can metabolize fructose when glucose metabolism shuts down -No pulmonary edema

Question 75

Naked mole rats brain survive??

Answer 75

-Brain slices recover function after anoxia -brain tissue remains viable for a long time in solution, with mice after a few minutes lose activity -for naked mole rats, activity decreased, but when oxygen was restored brain activity resumed. -calcium levels in mice went really high, were elevated in naked mole rats -calcium levels need to be maintained very carefully -elevated calcium can result in cell death which is what happens to mice neurons

Question 76

Describe the calcium channel situation for naked mole rats

Answer 76

-many types of calcium channels, study NMDA receptors, basically calcium channels really important for learning and memory. -centers are complex proteins made of 4 different subunits -form a port -different subunits that can form an NMTA receptor, 2 always conserved, other 2 variable -generally in babies these variable subunits are hypoxia resistant, as mouse matures it switches those out to non-hypoxia resistant -in naked mole rates this channel stays closed to cells don’t die

Question 77

-Elevated hypoxia inducible factor (HIF)- (naked mole rats)

Answer 77

basically a transcription factor that regulates production of other genes -many hypoxia genes activated when O2 levels low, -when O2 levels low, more of these genes that help are being activated

Question 78

Naked mole rat no edema and fructose situation-

Answer 78

Can metabolize fructose when glucose metabolism shuts down (cellular respiration maybe halted in low O2, one of the first steps turned off.) so ATP production goes waayy down -they use fructose lower in glycolytic pathway to break down and get ATP -No pulmonary edema/hypertension like most creatures in low oxygen high CO2

Question 79

Diving mammals and birds- 3 sources of O2 during a dive-

Answer 79

-air in lungs -bound to hemoglobin in blood -bound to myoglobin in muscle (one subunit, only holds one Oxygen I think?)

Question 80

Penguins and otters will be underwater for a decent amount of time, dolphins whales and seals will be for a long time

Answer 80

-penguins have lower amount of oxygen from respiratory system, more being pulled from the muscle -many diving mammals wont take breath at surface, blow all air out instead

Question 81

Main adaptations - cardiovascular

Answer 81

-Blood shunted from all other organs to brain and heart -Bradycardia -Strong blood buffering capacity -Large blood volume and O2 carrying capacity Release of red blood cells from spleen

Question 82

Main adaptations- -blood shunted, bradycardia, large blood volume

Answer 82

-blood shunted from all other organs to brain and heart, end up with less blood in the heart due to bradycardia which reduces the metabolic demand on the heart -bradycardia -Large blood volume and O2 carrying capacity- Release of red blood cells from spleen (during dive to add more to circulation during dive) at surface stored back in the spleen.

Question 83

Strong blood buffering capacity (diving mammals & birds)

Answer 83

-Change in lactic acid levels in the body, all areas with less blood flow undergo anaerobic respiration (brain and heart can’t) to maintain their metabolic need but causes build-up of lactic acid -lactic acid levels peak at the surface, don’t go down immediately. These tissues have so little blood flow that lactic acid is trapped within the tissues. Massive increase in acidity so buffering very important.

Question 84

Other main adaptations- (diving mammals and birds)

Answer 84

-high myoglobin concentrations -Reduced respiratory drive in response to high CO2 and H+ (way less sensitive than other mammals) -Neurons remain functional at low O2 -Reduced metabolic rate and energetic demands

Question 85

Why would a larger tidal volume be beneficial?

Answer 85

1) More oxygen molecules will be coming into the lungs, bigger breath may be more energetically beneficial to take one big breath than 2 breaths. We would have a reduction of total amount of stale air moving across gas exchange surfaces.

Question 86

Why would it be helpful for geese to maintain their flight muscles at a higher temperature?

Answer 86

2) More blood flow, more oxygen being delivered. The oxygen will be less tightly bound to the hemoglobin once it hits the heat, so it’ll go into the tissues better. (as temp increases graph shifts right)

Question 87

What could explain the higher hemoglobin and hematocrit in cave fish if RBC counts are the same?

Answer 87

3) The blind cave fish have bigger red blood cells than other fish species. (Fish and birds have nucleated RBCs)

Question 88

Why might diving mammals not rely much on air in their lungs during a dive?

Answer 88

1) The air may also provide an issue for buoyancy, which would require more oxygen usage, this way they sink and use less energy. The air is also going to compress, which would cause the alveoli to collapse (bc they have no cartilage to hold them open.) Nitrogen gas is prevented from building up so no air bubbles form in the cardiovascular system

Question 89

What is the advantage of releasing red blood cells during a dive rather than always having elevated red blood cell counts?

Answer 89

2) Increased red blood cell counts will make the blood volume go up, and cause it to be more viscous. This causes the blood pressure to be raised which probably isn’t ideal all the time, putting too much strain on the cardiovascular system.

Question 90

You are done

Answer 90

yay🎉