Aquatic Physiology Respiration gill diffusion hemoglobin pH Regulation gas bladder osmosis ion balance excretion 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 Regulation buoyancy

elasmobranchs and coelacanths lipid/oil-filled liver 1/3 of body wt 90% oil ~ food reserve ~ buoyancy at any depth, P also cartilage rigid fins for lift

South American lungfish Australian lungfish African bichir Asian climbing perch North American gar physoclistous physostomous osteichthyans: air/gas bladder Figure 5.1, 5 th 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: neutral buoyancy 10 m 20 m pressurevolume 30 m P ~ 1/V sink...

pikeperch 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 snaggletooth Astronesthes to 200 m rete mirabile =“wonderful net”

rete (mirabile) gas gland Figure 5.2 [5.1]Figure 5.3 [5.2 4 th and 3 rd Eds.] high pressuregas diffusion

very high pressure 2. salting out (HCO 3 - ) decrease in blood volume (V) and increases pressure (P) 1. Root effect (H + ) increases O 2 (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 impermeable expandable gas gland pressure:very highless highlower

Aquatic Physiology Respiration gill diffusion hemoglobin pH Regulation gas bladder osmosis ion balance excretion 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 Regulation osmoregulation

osmosis diffusion across a semi-permeable membrane pressure builds regulation... high to low (dilution) impermeable to solutes = ions/salts: Na + Cl - H + HCO 3 - NH 4 + NH 3 permeable to water

freshwater (+) (+ + +) gain water hyper-osmotic [more] fw fish fish 3x > freshwater environment

seawater (+ + +) (+) lose water fish : sw fish 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 water 3. gains salts 4. salts out gill ATP active transport 1. lose water some divalent salts Ca 2+, Mg 2+ out in urine no well-developed kidney hypo-osmotic

urea, salts elasmobranchs and coelacanths retain urea [saltwater] (+ + +) saltwater (+ + +) iso-osmotic = equal

OsteichthyesChondrichthyesBirds Nitrogen waste: produced stored

nitrogen pathways sizesmallerlarger solubilityhigherlower organ for excretiongillkidney expenselowerhigh toxicityhigherlower water requiredyesno total N/molecule 12 use in regulation ion exchangeiso-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 out against a concentration gradient

Figure 6.4 FW chloride cell (beta) move salts in against a concentration gradient

diadromy ~3 days chloride cells salt transport kidney urine function behavior

Week 7: Aquatic Regulation excretion

osmoregulatory structures 1. gill 2. kidney excretion: carbon dioxide nitrogen hydrogen

Figure th Ed. = NH 3 gill

gill excretion: carbon dioxide

gill excretion: nitrogen NH 3 + H + = NH 4 + ammonia ammonium ion

nitrogen pathways sizesmallerlarger solubilityhigherlower organ for excretiongill ~ NH 4 + kidney expenselowerhigh toxicityhigherlower water requiredyesno total N/molecule 12 use in regulation ion exchangeiso-osmosis

gill excretion: nitrogen Na + for NH 4 + 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 NH 4 + 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: water salts conservation: water salts

tetrapods fishes kidney nephron capsule = filter (salts) loop = reabsorb water: constriction salts: wave

organ nephron unit (100s to 1000s)

nephron capsule: loop: ammonia urea water salts enzymes

tetrapods fishes kidney nephron capsule = filter (salts) loop = reabsorb water: constriction salts: wave no constriction to concentrate urine