1.7 Exchange of nutrients and wastes

types of nitrogenous waste (recognise)

Urea

Uric acid

Ammonia

Requires very little energy

Requires more energy than ammonia

Requires a lot of energy

Requires a lot of water

Requires some water

Requires no/little water

Fish and amphibians(frogs)

Mammals

Reptiles and birds

Parts of the nephron (explain)

Bowman's capsule

Tubule (site of reabsorption)

Glomerulus

Loop of Henle

Distal convoluted tubule

proximal convoluted tubule

Network of capillaries which filter various substances from the blood

Surrounds the glomerulus, collects nitrogenous waste and other small soluble molecules forced by the high pressure in the glomerulus

Site of selective reabsorption

mineral ions (active transport)

glucose and amino acids

Establishing a salt gradient (water & salt reabsorption by active transport)

some water

Site of reabsorption

sodium (mineral ion/active transport)

water (osmosis)

Glomerular filtration: As a high pressure of blood from artery flows into the capillaries, it allows small molecules (glucose, amino acids, etc..) to pass from the glomerulus into the Bowman's capsule.

Selective reabsorption

occurs along the kidney tubules

purpose: to recover vital substances and ions.

Collecting Duct

Concentrates urine by reabsorping water (osmosis)

Secretion

??

Role of digestive enzymes (descirbe)

characteristics of absorptive surfaces (identify)

Protease

Lipase

Amylase

Large surface area

Thin and single layer

Increases contact area with enzymes/absorption

Increases diffusion rate

Microvilli(extensions on villi) on villi increases the surface area for absorption

image

Breaks down lipids into glycerol and fatty acids

Breaks down proteins to amino acids

breaks down amylose into disaccharide