Animal physiology

Question 1

Three nutritional needs

Answer 1

Fuel for cellular work - conversion of nutrients to energy

Raw materials for biosynthesis - Carbon - Nitrogen

Essential nutrients - items that cannot be biosynthesised

Question 2

Essential nutrients

Answer 2

AAs - 20 required - all found in meat

Fatty Acids - animals can synthesise most

Vitamins - Required in small amounts

Minerals - inorganic nutrients

Question 3

Ingestion

Answer 3

4 main methods

Suspension feeders

Fluid feeders

Substrate feeders

Bulk feeders

Question 4

Digestion

Answer 4

Mechanical and chemical

intracellular digestion

extracellular digestion

Question 5

Caecum

Answer 5

Pouch that connects where small + large intestine meet

Enlarged in herbivores for cellulose digestion (holds microbiome)

Question 6

Mutualistic organisms in digestive system

Answer 6

Willow ptarmigan - 2 large caeca for cellulose fermentation

Hoatzin - enlarged muscular crop that houses microbes

Termites - eat wood - house bacteria and protists in hind gut - break down cellulose

Iguana - Has a microbial flora in hindgut

Question 7

Ruminants

Answer 7

specialised fermentation chamber - called a rumen that houses complex communities of microorganisms

Four chambered stomach

Question 8

Coprophagy

Answer 8

Ingest soft faeces that are products from the caecum - lagomorphs

Question 9

Countercurrent flow in fish

Answer 9

Blood flow in opposite direction to water passing over the gills

Bloods is always less saturated with O2 than water O2 always diffuses to blood

Question 10

negative pressure breathing

Answer 10

pulls air into lungs

exhalation is passive

Mammals

Question 11

Positive pressure breathing

Answer 11

forcing air in and out of lungs

amphibians

respire across skin

Question 12

Bellow system

Answer 12

Birds

numerous air sacs

Incoming air does not mix with stale air

every ex and inhalation completely renews the air

Question 13

Single circulatory system

Answer 13

Fish - blood leaving heart passes through two capillary beds

two chambered heart

blood pressure drops - muscle contractions accelerate circulation

Question 14

Double

Answer 14

Mammals and birds

Amphibians - 3 chambered heart - pulmocutaneous circuit - picks up O2 through lungs and skin

Question 15

Osmoconformers

Answer 15

isoosmotic - match osmolarity of environment - passive or aggresive

Most marine inverts

some marine verts - hagfish

crab-eating frog and sharkas/rays - urea retention regulation to remain isoosmotic

Question 16

Osmoregulation in marine vertebrates

Answer 16

Hypoosmotic to sea water - lose water to environment

Drink large amounts of sea water and excrete excess salt via kidneys and gills - pump out cl- and Na2+ follows passively along electrical gradient

Question 17

Osmoregulation in freshwater vertebrates

Answer 17

Opposite to marine

Constantly take in water by osmosis - large amounts of dilute urine - drink v little water

Salts lost by diff are replaced in foods and by uptake across gills

Pump in Cl- - Na2+ follws passively

Question 18

Marine mammals

Answer 18

ingest salt via sea water and food and excrete concentrated urine

highly effective kidneys

Question 19

Salt excreting nasal glands

Answer 19

marine birds - remove excess NaCl from the blood - fluid secreted is much saltier than sea

Secretory tubules each lined with single layer of transport epithelial cells

actively pump salt from blood into tubules - counter current exchange - enhances salt transfer - results in net gain of water

Question 20

Osmoregulation in terrestrial animals

Answer 20

drinking water - eating moist foods - metabolic water

Kangaroo rat can survive without drinking

Loses so little water - 90% is replaced by water generated metabolically - extra water comes from seeds

Ostriches have two chambered nasal pasasge that can remove water vapour as the exhale

Question 21

Nitrogenous wastes

Answer 21

Ammonia - highly toxic - quick excretion - access to water - aquatic animals

Urea - terrestrial animals - liver converts ammonia to urea - expensive - less toxic - stored in high concs in kidney

Uric acid - insects, snails, reptiles, birds - less toxic than ammonia and urea - insoluble in water - more expensive to produce than urea - good for animals with low access to water

Question 22

Protonephridia

Answer 22

flat worms

network of tubules connect to external openings on animal

smallest branches capped by cellular unit called flame bulb - beating cilia draw in water and solutes - fluid filtrate excreted out via tubules

Question 23

Malpighian tubules

Answer 23

Insects

Solutes and nitrogenous wastes are secreted into tubules and then passed into the alimentary cana - water follows by osmosis

solutes and most of water reabsorbed by rectum

Relatively dry waste

Question 24

Antennal glands

Answer 24

located in the head that open near antennae

Consist of a sac - excretory tubule - bladder

Urine formed by filtration and reabsorption

crustaceans

Question 25

Mammalian excretory system

Answer 25

Each kidney is supplied with blood by renal artery and drained by renal vein

25% of blood is directed through kidneys

Urine exits each kidney through duct called a ureter

Both ureters drain into a common urinary bladder - urine expelled through urethra

Question 26

Kidney structure

Answer 26

renal cortex

renal medulla

Nephron - the functional unit - ball of capillaries - glomerulus - filtration occurs

Question 27

Nephron

Answer 27

Cortical nephrons - are confined to the renal corex - small loops of Henle

Juxtamedullary nephrons - have loops of Henle that extend into the renal medulla

Loop of henle - pumps ions into the medulla and creates an area of high urea conc deep in medulla - water follows by osmosis - countercurrent multiplier

Question 28

Mammal kidney function

Answer 28

filter blood through glomerulus that has openings in its walls

Driven by circulatory pressure - water, solutes and N waste move from capillaries to the interstitial fluid

Selective reabsorption occurs and water and useful solutes are reabsorbed by moving into the medulla

Question 29

Antidiuretic hormone

Answer 29

ADH

Changes in permeability of epithelia along collecting ducts of kidneys - influencing the reabsorption of water

-ive feedback controls activity of osmoreceptor cells in the hypothalamus and ADH is released

Question 30

Loop of henle adaptations

Answer 30

Length correlates with demand for conserving water

Kangaroo rat has long loop - steep conc grads - v concentrated urine

Freshwater mammals have short loops - low risk of dehydration