Aquatic Physiology

RespirationgilldiffusionhemoglobinpH

Regulationgas bladderosmosis ion balanceexcretion

Chapter 3: Figures 3.1, 3.2, 3.3, Table 3.1

Chapter 4: Figures 4.4, 4.5, 4.6 (Eq.)

Chapter 5: Figures 5.1, 5.2, 5.3 (5th ed.)

Chapter 6: Figures 6.1, 6.2, 6.4, 6.6

Week 7:

Aquatic Regulationbuoyancy

elasmobranchs and coelacanthslipid/oil-filled liver

1/3 of body wt90% oil

~ food reserve ~ buoyancy at any depth, P

also cartilagerigid fins for lift

South American lungfish

Australian lungfish

African bichir

Asianclimbing perch

North American gar

physoclistous physostomous

osteichthyans:air/gas bladder

Figure 5.1, 5th ed. only.

gas bladder

~ air/gas reserve~ buoyancy declines w/depth, P

PV = nRT (ideal gas law)

pressure x volume = # gas molecules x constant x temperature

aquatic environment: 10 m decrease in depth ~ 1 atm increase in pressure

gas bladder:

neutralbuoyancy

½ @ 10 m

1/3 @ 20 m

pressure volume 1/4 @ 30 m

P ~ 1/V

sink...

pike perch

physostomous (open to gut/ mouth) physoclistous (closed to gut/mouth)

Gas Bladder: 2 types

surface to 100 m > 100 m depths

rete (mirabile)gas gland

physostomous (open to gut/ mouth) physoclistous (closed to gut/mouth)

25x rete length ~ 10x max. depth

gas bladder gas gland and rete system

deepsea snaggletoothAstronesthesto 200 m

rete mirabile =“wonderful net”

rete (mirabile)gas gland

Figure 5.2 [5.1] Figure 5.3 [5.2 4th and 3rd Eds.]

high pressure gas diffusion

very high pressure

2. salting out (HCO3-)

decrease in blood volume (V)and increases pressure (P)

1. Root effect (H+)increases O2 (n)and increases pressure (P)

PV = nRT

rete (mirabile)

bicarbonate equillibrium

glucose:a. lactate (salting out)b. hydrogen (Root effect)c. carbon dioxide (inflation)

surfactant increases surface wall tension to prevent pressure collapses (see in lungs)

Gas bladder

otherwise impermeableexpandable

gas gland

pressure: very high less high lower

Aquatic Physiology

RespirationgilldiffusionhemoglobinpH

Regulationgas bladderosmosis ion balanceexcretion

Chapter 3: Figures 3.1, 3.2, 3.3, Table 3.1

Chapter 4: Figures 4.4, 4.5, 4.6 (Eq.)

Chapter 5: Figures 5.1, 5.2, 5.3 (5th ed.)

Chapter 6: Figures 6.1, 6.2, 6.4, 6.6

Week 7:

Aquatic Regulationosmoregulation

osmosisdiffusion across a semi-permeable membrane

pressure builds

regulation...

high to low (dilution)

impermeable to solutes = ions/salts: Na+ Cl-

H+ HCO3-

NH4+ NH3

permeable to water

freshwater (+)

(+ + +)

gain water

hyper-osmotic [more]

fw fish

fish 3x > freshwater environment

seawater (+ + +)

(+)

lose water

fish : swfish 3x < saltwater environment

hypo-osmotic [less]

osmoregulatory structures

1. gill

2. kidney

Figure 6.1

osmoregulation

1. gill

2. kidney

more simplified...

freshwater (+)

(+ + +)1. gains water

osmosis

2. loses water (dilute urine)

kidney production

3. loses salts

4. salts in

gill active transport/exchange

hyper-osmotic

saltwater (+ + +)

(+)

osmosis

2. drinks water3. gains salts

4. salts out

gill ATP active transport

1. lose water

some divalent salts Ca2+, Mg2+ out in urineno well-developed kidney

hypo-osmotic

urea, salts

elasmobranchs and coelacanths

retain urea [saltwater]

(+ + +)

saltwater (+ + +)

iso-osmotic = equal

Osteichthyes Chondrichthyes Birds

Nitrogen waste:

produced stored

nitrogen pathways

size smaller largersolubility higher lowerorgan for excretion gill kidneyexpense lower hightoxicity higher lowerwater required yes nototal N/molecule 1 2use in regulation ion exchange iso-osmosis

elasmobranchs and coelacanths

(+ + +)

saltwater (+ + +)

iso-osmotic = equal

1. gains salts in food

2. salts out via rectal gland

Figure 6.1

osmoregulation

1. gill

2. kidney

base of lamellae

main osmoregulatory structure

chloride cells

Figure 6.2

SW chloride cell (alpha)~ “rectal gland”

move salts outagainst a concentration gradient

Figure 6.4

FW chloride cell (beta) move salts inagainst a concentration gradient

diadromy

~3 days

chloride cellssalt transport

kidneyurine function

behavior

Week 7:

Aquatic Regulationexcretion

osmoregulatory structures

1. gill

2. kidney

excretion:carbon dioxidenitrogenhydrogen

Figure 6.6

5th Ed. = NH3

gill

gill excretion:carbon dioxide

gill excretion:nitrogen

NH3 + H+ = NH4+

ammonia ammonium ion

nitrogen pathways

size smaller largersolubility higher lowerorgan for excretion gill ~ NH4

+ kidneyexpense lower hightoxicity higher lowerwater required yes nototal N/molecule 1 2use in regulation ion exchange iso-osmosis

gill excretion:nitrogen Na+ for NH4

+

sodium for ammonium same electrochemical (+) charge

gill excretion:hydrogen

1.

sodium for hydrogen same (+) charge

3 pathways: 2. 3.

freshwater (+)

(+ + +)1. gains water

osmosis

2. loses water (dilute urine)

kidney production

3. loses salts

4. salts in via NH4+ and H+ exchange for Na+

gill active transport/exchange

hyper-osmotic

chloride for bicarbonate ion same (-) charge

electrochemical gradients (+ and -)

osmoregulatory structures

1. gill

2. kidney

excretion:watersalts

conservation:watersalts

tetrapods

fishes

kidney nephron

capsule = filter (salts)

loop = reabsorb water: constriction salts: wave

organ nephron unit (100s to 1000s)

nephron

capsule:

loop:

ammoniaurea

ureawater

salts

enzymes

tetrapods

fishes

kidney nephron

capsule = filter (salts)

loop = reabsorb water: constriction salts: wave

no constriction to concentrate urine