Unit 13: Excretion in Humans

Define excretion

removal of waste products of metabolism & substances in excess of requirements

Lungs excrete __ via __

co2, respiration

Kidneys excrete excess __, m__ s__, u__

h2o, mineral salts, urea

Where is urea made?

liver

What is urea made from?

excess amino acids

Liver
A__ of a__ a__ → p__ e.g. f__

assimilation, amino acids, protein, fibrinogen

Liver
D__: removal of __ containing part of a__ a__ to form __

deamination, n2, amino acids, urea

Deamination cycle:
A__ a__ → N__ → __

amino acid, nh3, urea

name (going in)

renal artery

name (going out)

renal vein

name

ureter

name

renal pelvis

name

medulla

name

cortex

Function of the ureter

carries urine to the bladder

Function of the medulla

receives blood from renal artery

The n__ are found in the m__

nephrons, medulla

Function of the cortex

filters blood

Whole process:
Blood → k__ → u__ → b__ → u__

kidneys, ureter, bladder, urethra

name

glomerulus

name

bowman’s capsule

name

tubule

name

loop of henule

Filtration - G__
> H__, g__, u__, salts, via d__
> p__ too large to pass

glomerulus, h2o, glucose, urea, diffusion, proteins

Reabsorption (back into the blood) – T__
> ALL __, via a__ t__
> MOST H__, via o__
> SOME s__, via d__

tubule, glucose, active transport, h2o, osmosis, salts, diffusion

Secretion of U__
> u__ + excess H__ + e__ mineral i__
> u__ → bladder → u__

urine, urea, h2o, excess, ions, ureter, urethra

Factors of Vol. & Conc of Urine
H__ intake: ↑ = ↑vol, __(more/less)conc

h2o, less

Factors of Vol. & Conc of Urine
T__: ↑ = ↑s__ = __(more/less)vol

temp, sweat, less

Factors of Vol. & Conc of Urine
E__: ↑ = ↑s__ = __(more/less)vol

exercise, sweat, less

Why do we excrete urea & CO₂?

toxic in high conc