anatomy and psysiology of the kidneys

Question 1

how big is the kidneys?

Answer 1

about 12cm long, 6cm wide and 3cm thick

Question 2

what is the renal capsule?

Answer 2

fibrous capsule around the kidney

Question 3

what is the renal cortex?

Answer 3

outer region of kidney

Question 4

what is the renal medulla?

Answer 4

inner region; composed of renal pyramids

Question 5

what are renal columns?

Answer 5

extensions of cortex that dip into medulla

Question 6

what is the renal pelvis?

Answer 6

funnel shaped sack; superior end of ureter

Question 7

what is the major calyces?

Answer 7

large tubes that merge to form the renal pelvis

Question 8

what is the minor calyces?

Answer 8

small tubes that merge to form major calyces

Question 9

what is the renal artery?

Answer 9

branches off abdominal aorta, enters kidneys through hilum

Question 10

what is segmental arteries ?

Answer 10

branch off renal artery

Question 11

what is interlobar arteries?

Answer 11

branch off segmental arteries, flow between renal pyramids

Question 12

what is arcuate arteries?

Answer 12

branch off interlobar arteries, arch around renal pyramids

Question 13

what is cortical radiate arteries?

Answer 13

branch off arcuate arteries

Question 14

what does the renal corpuscle contain?

Answer 14

glomerulus
bowman’s capsule

Question 15

what is the renal tubule?

Answer 15

• extends from bowman’s capsule to collect duct
• distal tubules of several nephrons empty into a collecting duct
• collecting duct continues through the medulla and drains through the renal papilla into a minor calyx

Question 16

what are two types of nephrons in the kidneys?

Answer 16

cortical nephron
juxtamedullary nephron

Question 17

what are cortical nephrons?

Answer 17

-lie almost completely in renal cortex
-have short nephron loops
-renal corpuscles located near surface of kidney

Question 18

what are juxtamedullary nephrons?

Answer 18

• smaller percentage
• have long nephron loops, that extend deep into medulla
• renal corpuscles lie deep in renal cortex
• important in regulating water balance and urine concentration

Question 19

what is the afferent arteriole?

Answer 19

branch off cortical radiate arteries; each enters a different nephron

Question 20

what is the glomerulus?

Answer 20

capillary cluster that branched from afferent arteriole (filters blood in each nephron)

Question 21

what is the efferent arteriole?

Answer 21

arises from merging of glomerulus capillaries (transports blood that was not filtered by glomerulus)

Question 22

what are peritubular capillaries?

Answer 22

branches off the efferent arteriole; surrounds renal tubules

portal system (blood circulating through two capillary beds)

Question 23

what is the vasa recta?

Answer 23

• branches off efferent arteriole
• run parallel to the tubules descending into the medulla
• form capillary networks and then return to cortex
• 10-15% of renal blood flow reached the medulla

Question 24

what does the juxtaglomerular apparatus regulate?

Answer 24

regulates the secretion of the enzyme renin
- monitors and adjusts blood pressure and NaCl content of filtrate

Question 25

what is the macula dense?

Answer 25

tall, closely packed cells of the ascending limb, monitors NaCl content of filtrate

Question 26

what are juxtagomerular cells?

Answer 26

vascular smooth muscle cells of afferent ateriole Monitors bp

Question 27

what are the three processes of urine formation?

Answer 27

Glomerular filtration Tubular reabsorption Tubular secretion

Question 28

what is glomerular filtration

Answer 28

- performed by specialised glomerular capillaries - water and small molecules are filtered - filter fluid enters renal tubules and becomes tubular fluid

Question 29

what happens during tubular reabsorption?

Answer 29

transfer of filtered substances from renal tubules to peritubular capillaries only reclaims useful substances, while wastes continue to become urine

Question 30

what happens during tubular secretion?

Answer 30

transfer of certain substances from peritubular capillaries to renal tubules adds waste products and excess substances to forming urine

Question 31

what is the composition of glomerular filtrate?

Answer 31

mainly water glucose, amino acids urea, uric acid, creatine, creatinine Ions

Question 32

what are substances that doesn’t appear in filtrate?

Answer 32

blood cells, plasma proteins, large anions, protein bound minerals and hormones

Question 33

what is hydrostatic pressure?

Answer 33

blood pressure in the vessel - pushes water/small molecules from the blood out into the bowman’s space - as the fluid pressure increases in the bowman’s space it starts to move back into the blood, the capsular hydrostatic pressure - net filtration must be positive for filtration to occur

Question 34

what are forces opposing filtration?

Answer 34

- glomerular capillary colloid osmosis pressure (due to plasma proteins in glomerulus) - capsular hydrostatic pressure

Question 35

what is the average GFR in an adult?

Answer 35

180L/day