Excretory Products N Their Elimination

Question 1

Kidneys are retro peritoneal in position.

T/F

Answer 1

True.

Retro peritoneal structures lie outside the peritoneum (parietal peritoneum) I.e covered by peritoneum on one side.

Question 2

Kidneys are located between ___________ vertebres.

Answer 2

12 thoracic and 3 lumbar I.e T12 - L3

Question 3

With respect to size, length of each kidney is about _____ and width ______ and depth ______.

Answer 3

10-12cm in length
5-7cm in width
2-3cm in depth (thickness)

Question 4

In humans _________ kidney is lower than ______ in position,because __________.

Answer 4

Right kidney is lower in position than the left.
Right kidney is pushed downwards by massive liver.
In rabbits, the case is reverse I.e right is higher than the left kidney.

Question 5

If the renal fascia is ruptured, the kidney loses its position and descends downwards, a condition is called

Answer 5

Nephrotosis or floating kidneys.

Question 6

Renal cortex protrudes into renal medulla at

Answer 6

Columns of bertini or renal columns.

It is the space between 2 consecutive renal pyramids.

Question 7

Functional units of kidney are

Answer 7

Nephrons or uriniferous tubules.

Question 8

Each kidney has about _______nephrons.

Answer 8

100,000 nephrons.

** 1 million nephrons (NCERT)

Question 9

Parietal membrane of bowmans capsule is made of

Answer 9

Simple squamous epithelium.

Question 10

visceral membrane of bowmans capsule is made of

Answer 10

Special cells called podocytes.

These are irregular cells that line the glomerular capillary wall.

Question 11

What is nephric filtrate?

Answer 11

It is filtered blood, having the composition as that of blood except formed elements and large proteins.
Blood is comparatively concentrated than nephric filtrate.

Question 12

Renal affarent/efferent arterioles has comparatively greater lumen while affarent/efferent arteriole has lesser lumen.

Answer 12

Renal affarent arterioles has comparatively greater lumen while efferent arteriole has lesser lumen.

Question 13

What is filtration membrane?

It’s thickness is _______.

Answer 13

It’s m/o wall of blood vessel wall and visceral layer of bowmans capsule.
Thickness = 0.24m

Question 14

What is GCHP ?

Answer 14

Glomerular blood capillary hydrostatic pressure: pressure exerted by blood on blood vessel wall.
It’s a positive pressure.
Equal to 60mmHg.
Sends blood plasma out of blood vessel into capsular space, through fenestra.

Question 15

What is CHP?

Answer 15

Capsular hydrostatic pressure : pressure exerted by nephric filtrate onto the blood vessel wall.
It’s a negative pressure.
Equal to 20mmHg.

Question 16

What is BCOP?

Answer 16

Blood colloidal osmotic pressure: pressure exerted by nephric filtrate over blood.
It’s a negative pressure.
Equal to 30mmHg.

Question 17

What is GFR?

Answer 17

Glomerular filtration rate: amount of nephric filtrate formed per min or per day.
Per min = 125ml
Per day = 180L

Question 18

What is urine outflow?

Answer 18

99% of nephric filtrate is reabsorbed and only 1% is excreted as urine = 1.5-2L /day. This is k/a urine outflow.

Question 19

Filtration fraction for a normal kidney is

Answer 19

15-20%.

Filtration fraction = GFR/RPF =125/650=20%

Question 20

What is RPF?

Answer 20

Amount of blood plasma that enters the kidneys per minute.[(55% of 1200) =650].

Question 21

Volume of blood that enters the kidney per min is

Answer 21

1100-1200ml which is 1/5th of cardiac output.

Question 22

_____is the major site for tubular reabsorption.

Answer 22

proximal convulated tubule .

Question 23

What is tubular reabsorption ?

Answer 23

tubular reabsorption means the absorption of electrolytes and water into nearby blood vessels.

Question 24

____________ is reabsorbed in proximal convulated tubule .

Answer 24

Na+ , K+ , H2O, small amount of urea, bicarbonate ion.

70-80% of electrolytes are reabsorbed which include 100% of glucose and amino acids.

Question 25

What is tubular secretion?

Answer 25

Secretion of substances like electrolytes from blood vessels into renal tubule.

Question 26

At proximal convulated tubule, electrolytes like __,__,__ are secreted from blood vessels into nephric filtrate in renal tubules.

Answer 26

H+ , K+ , NH4+

Question 27

What is tubular absorptive maxima(TAM)?

Answer 27

max. Amount of substance or electrolyte that can be absorbed per 100ml of the nephric filtrate.
For glucose, TAM = 180mg/dl

Question 28

Normal blood sugar level is equal to ____?

Answer 28

120mg/dl.

As it exceeds 120mg/dl, glucose will start appearing in urine.

Question 29

Thin segment of descending limb of loop of Henele is lined with _______ epithelium which is permeable for _____ and impermeable for ______.

Answer 29

Squamous epithelium

Permeable for water; impermeable for ions.

Question 30

Thin segment of ascending limb of loop of Henele is lined with _______ epithelium which is permeable for _____ and impermeable for ______.

Answer 30

Ciliate cuboidal epithelium

Permeable for ions ; impermeable for water.