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Excretory System: Chapter 13 Mind Map Part- 1, Deamination: Removal of…
Excretory System: Chapter 13
Mind Map
Part- 1
Excretion
Excretion is the
elimination of unwanted things
.
Excretion is the
removal of waste products of metabolism and substances in excess of requirements.
Eliminated things may include
carbon dioxide, water, simple compounds and ions, excess medicines and urea.
Removal of:
Waste products by reactions, excess water and salts, spent hormones and drugs
.
Need of excretion:
Carbon dioxide dissolves
in fluids to form
carbonic acid.
This
increases the acidity of blood and may affect the action of enzymes.
Thus the lungs, expel out carbon dioxide during exhalation.
When excess amino acids are broken down
(by the process of deamination)
ammonia is formed.
It is alkaline and toxic. It is then converted to urea which is much less poisonous. Urea is given away by urine.
Salts and water are removed if in excess, by the kidneys.
Spent hormones
are modified in the
liver
, and the unwanted part is
excreted in the urine
.
Urine
is a watery solution which contains excess salts + spent hormones + nitrogenous waste products.
Excretion
helps in the
maintenance of concentrations of salts and water in the blood.
Excretory organs:
Skin
: Water and salts come out as
sweat
(H2O, NaCl, Urea)
Lungs
: Get rid of
CO2
and loose a great deal of
water vapour
.
Liver
: Produces
Urea
,
modifies drugs, spent hormones and urea
and excretion of
bilirubin
(product of breakdown of haemoglobin, responsible for the colour of faeces).
Kidneys and urinary system:
Removes urea and other nitrogenous waste, expels excess water, salts, hormones and drugs.
Renal artery
: Carries oxygenated blood to the kidneys. Renal artery branches into 2 arteries to carry
oxygenated and unfiltered blood
to the kidneys.
Renal vein:
Carries
purified (filtered), deoxygenated blood
which connects to the vena cava.
Kidneys
regulate water and filter blood by
ultrafiltration
.
Most movement of particles
occurs here. Kidney cells have more mitochondria to perform active transport.
Ureters
are thin muscular tubes coming out from each kidney that
opens into the urinary bladder and drains the urine out of the kidneys.
Urinary bladder
is pear shaped. It
stores urine
before its discharge. It has
splinter muscles.
Urethra
is a muscular tube, from the neck of the bladder. It
discharges urine out
through the opening.
Deamination: Removal of nitrogen containing part of amino acids to form urea.
Amino acids ---> Glycogen (stored) + Urea (excreted)