excretion

Question 1

Definition of excretion

Answer 1

The process by which metabolic waste products and toxic substances are removed from the body of an organism

Question 2

what is metabolism ‘

Answer 2

The sum total of all chemcial reactions occuring in the cells of an organism

Question 3

what is anabolism

Answer 3

Metabolic reaction where simple molecules are built up into complex ones with a net intake of energy

eg : photosynthesis , conversion of excess glucose to glycogen for storage

Question 4

what is catabolism

Answer 4

Metabolic reaction where complex molecules are broken down to simpler ones with a net release of energy

Question 5

4 diff between excretion and egestion

Answer 5

1) egestion is the discharge of leftover undigested matter from the alimentary canal or digestive tract while excretion is discharge of metabolic waste from the body
2) Egestion takes place at the anus (smtimes at the mouth ) but excretion takes place at the uthera (urine ) , skin (sweat ) or mouth ( saliva)
3) matter egested is faecas but matted excretion are components of sweat , saliva , urine etc.
4) unvolve orgarns in the digestive system but excretion involves organs like skin liver lungs , large intestine (colon and kidney )

Question 6

what is egestion

Answer 6

the removal of waste substance , mainly undigested matter , from the alimentary canal . There undigested materials (e.g celluslose ) have never been absorbed into cells and hence they are not produced as a result of metabolic reactions within cells

Question 7

what is excretion

Answer 7

the removal or waste substance that are produced by metabolic reactions that occur within cells

Question 8

Draw the mammalian urinary system

Answer 8

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Question 9

reconise the sturcture of a kidney

Question 10

what is the hilum

Answer 10

a depression where renal artery , renal vein and nerves are connected to the kidney

Question 11

what is the urinary bladder

Answer 11

elastic muscular bag in front of the rectum that stores urine

Question 12

what is the sphincter muscle

Answer 12

its found at the bottom of the bladder , control urine flow into the uretha and out of the body

Question 13

uretha

Answer 13

Duct through which urine passes from the urinary bladder to outside the body

Question 14

what is renal arteries

Answer 14

brings oxygenate blood containing urea , excess water + heat from the heart to the kidneys

Question 15

renal veins

Answer 15

bring deoxygenated blood ( from which urea , excess water + heat have been removed away from the kidneys to the heart )

Question 16

what are nephron

Answer 16

1) basic functional unit of the kidneys , 2) that are tiny tubules where urine is formed .
3) each kidneys has about 1 mill nephrons 4) each nephron has 4 main parts (bowmans capsule , proximal convuleted tubule , loop of henle , distal convoluted tubule . 5) severa nephrons open into a tube known as the collecting duct .

Question 17

pathway of nephron

Answer 17

1) enters kidneys via the renal artery
2) the branch of renal artery splits into many arterioles
3) an arteriole further divides into a network of capillaries (glomerulus)
4) blood leaves the glomerulus and enters a network of capillaries surrounding the the rest of the nephron (PCT , DCT, loop of henle )
5) blood flows into venules from capillaries

Question 18

Function of ultrafiltration

Answer 18

(occurs in the glomerulus ) removes small molecules from the blood . most of the blood plasma is forced out of the glomerular blood capillaries into the bowmans capsule to form the glomerular filtrate