Life processes - Excretion notes
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Excretion-
The biological process of removal of harmful metabolic wastes in living
organisms.
- Excretion in human beings-
(Refer to figure
6.13 page no. 110 of N.C.E.R.T Text
book)
§
Organs of
excretory system- (i) Kidneys
(iii) Urinary bladder
(ii) Ureters (iv) Urethra
§
Kidneys-
(i)
Two in number
(ii)
Bean shaped
(iii)
Present in abdomen on either side of the
backbone
(iv)
Basic unit is nephron.
a. Glomerulus-
Group of capillaries (cluster) present in Bowman’s capsule to receive
blood from renal artery and filters it.
b. Bowman’s
capsule- Cup shaped structure, which contains glomerulus.
c. Convoluted tubule- is long and reabsorbs vital
nutrients like glucose, amino acids, salts, urea and water.
Functions of Kidneys- (a) Filtration & removal
of Nitrogenous wastes
(b)
Reabsorption of vital nutrients
§
Ureters- Transport the urine formed in the
kidneys to the urinary bladder.
§
Urinary bladder- Muscular bag like structure to
store urine.
§
Urethra- Helps in removal of urine when the
Urinary bladder is full.
§
Artificial kidney- Principle: Dialysis
- Excretion in plants-
- Gaseous wastes- CO2 in respiration & O2 in photosynthesis are removed by the process of diffusion.
- Excess water- is removed by transpiration.
- Other wastes- (i) Stored in cellular vacuoles or in leaves, which fall off or as
gums, resins,
etc. in old xylem.
(ii) Excreted in soil.
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Important
diagrams-
1.
Open & close stomata
2.
Steps of nutrition in Amoeba
3.
Alimentary canal of human beings/ Digestive
system of human beings
4.
Respiratory system of human beings
5.
Structure of heart.
6.
Excretory system of human beings
7.
Structure of nephron
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