Functions of the kidneys. General organization of the kidneys and urinary tract. Renal blood supply. Urine formation. Glomerular filtration

Question 1

Functions of the kidneys - 1

Answer 1

RAAS system

when blood pressure is low, the kidneys secrete renin

renin converts angiotensinogen into angiotensin I ACE converts into angiotensin II

• angiotensin II is a potent vasoconstriction - high BP
• aldosterone causes water/ sodium retained

Question 2

Functions of the kidneys - 2

Answer 2

VITAMIN D

kidneys convert inactive vitamin D calcidiol into active form called calcitriol
needed for bone/ teeth health

Question 3

Functions of the kidneys - 3

Answer 3

BLOOD FILTRATION

nephrons are basic functional units of kidney
Involved in filtration of toxins, electrolytes, drugs, salts from BLOOD

Question 4

Functions of the kidneys - 4

Answer 4

EXCRETION

Toxins, urea, creatinine, uric acid TUCU
from BLOOD

Question 5

Functions of the kidneys - 5

Answer 5

PH balance

too acidic = excrete H+/ keep HCO3-

too alkaline = keep H+/ excrete HCO3-

Question 6

Functions of the kidneys - 6

Answer 6

ELECTROLYTES

kidneys control amounts of Na+/K+/Ca2+
using reabsorption + excretion

Question 7

Functions of the kidneys - 7

Answer 7

GLUCONEOGENESIS

kidneys can produce glucose from non-carbohydrate sources

useful during fasting state

Question 8

Functions of the kidneys - 8

Answer 8

DETOXIFICATION

kidneys detoxify drugs/ meds into urine

Question 9

General organisation of the kidneys - 1

Answer 9

LOCATION

located retro-peritoneally
bilateral to spine
below ribs

Question 10

General organisation of the kidneys - EXTERNAL 1

Answer 10

• renal capsule = fibrous layer

Question 11

General organisation of the kidneys - EXTERNAL 2

Answer 11

• renal cortex = granular layer, contains glomeruli, PCT-DCT

Question 12

General organisation of the kidneys - EXTERNAL 3

Answer 12

• renal medulla = contains pyramids separated by columns, contains loops of henle

Question 13

General organisation of the kidneys - EXTERNAL 4

Answer 13

• renal hilum = site of exit for vessels + ureter

Question 14

General organisation of the kidneys - INTERNAL 1

Answer 14

nephron
- functional unit of kidney
- filter blood
- form urine

Question 15

General organisation of the kidneys - INTERNAL 2

Answer 15

• glomerulus = group of capillaries for blood filtration

Question 16

General organisation of the kidneys - INTERNAL 3

Answer 16

• bowmans capsule = coating around glomerulus

Question 17

General organisation of the kidneys - renal tubule 1

Answer 17

PCT
- reabsorbs a lot of water/ ions/ nutrients

Question 18

General organisation of the kidneys - renal tubule 2

Answer 18

loop of henle

forms a conc gradient in renal medulla
for urine concentration/ water reabsorption

Question 19

General organisation of the kidneys - renal tubule 3

Answer 19

DCT

regulation of na+/k+/ca2+ balance

Question 20

General organisation of the kidneys - renal tubule 4

Answer 20

collecting duct

collects urine from nephrons sent to renal pelvis

Question 21

General organisation of the urinary tract - URETER

Answer 21

URETER

muscular tube

transport urine kidney -> urinary bladder

via peristalsis

Question 22

General organisation of the urinary tract - URINARY BLADDER

Answer 22

URINARY BLADDER

hollow organ

containing trigone + detrusor smooth muscles

storage of urine

Question 23

General organisation of the urinary tract - URETHRA

Answer 23

URETHRA

opening of urinary bladder

• internal urethral sphincter = involuntary + external urethral sphincter = voluntary

removal of urine

Question 24

Renal blood supply - 1

Answer 24

abdominal aorta -> a. renalis -> afferent arteriole -> glomerulus -> efferent arteriole -> peritubular capillaries -> v. renalis -> inferior vena cava

Question 25

Urine formation - 1

Answer 25

FILTRATION

blood enters from a. afferent into glomerulus + pressure from ions = hydrostatic pressure developed

glomerulus has x3 filtration layers
- basement membrane
- endothelium
- podocytes

producing filtrate without proteins but with waste, electrolytes, glucose

Question 26

Urine formation - 2

Answer 26

REABSORPTION

filtrate moves through renal tubules (PCT, loop of henle, DCT)

most contents get reabsorbed back into bloodstream via peritubular capillaries
- glucose
- amino acids
- na/k

Question 27

Urine formation - 3

Answer 27

secretion

kidneys secrete waste like drugs

blood -> renal tubules -> urine

for pH/ electrolyte balance

Question 28

glomerular filtration - definition

Answer 28

process when blood plasma is filtered through glomerulus, forming glomerular filtrate

Question 29

glomerular filtration - feature 1

Answer 29

GFR
= volume of filtrate produced
= 125ml/min

Question 30

glomerular filtration - feature 2

Answer 30

hydrostatic pressure from glomerularus promotes filtration

Question 31

glomerular filtration - feature 3

Answer 31

colloid osmotic pressure
- from plasma proteins
- prevents filtration

Question 32

glomerular filtration - feature 4

Answer 32

capsular pressure
- from bowman capsule
- prevents filtration

Question 33

glomerular filtration - structure 1

Answer 33

basement membrane
prevents large negatively charged proteins from entering

Question 34

glomerular filtration - structure 2

Answer 34

endothelium of glomerular capillaries
= fenestrated allowing passage of water but not blood

Question 35

glomerular filtration - structure 3

Answer 35

podocytes
prevents passage of large molecules