Lecture 23

Question 1

Urine flows

Answer 1

Urine flows –> kidney –> down its ureter –> bladder –> the outside via the urethra

Question 2

Urinary system =

Answer 2

kidneys, ureters, urinary bladder, and urethra

Question 3

Filter:

Answer 3

the blood and return most of water and solutes to the bloodstream

Question 4

Overview of Kidney Functions:

Answer 4

1. Regulation of blood ionic composition, blood pH, osmolarity, and glucose, blood volume, blood pressure
2. Release of erythropoietin and calcitriol
3. Excretion of wastes & foreign substances

Question 5

Regulation of blood ionic composition:

Answer 5

Na+, K+, Ca+2, Cl- and phosphate ions

Question 6

Regulation of blood volume:

Answer 6

conserving or eliminating water

Question 7

Regulation of blood pressure

Answer 7

• secreting the enzyme renin

- adjusting renal resistance

Question 8

Drainage system fills

Answer 8

renal sinus cavity

Question 9

Drainage system minor and major calyces…

Answer 9

empty into the renal pelvis which empties into the ureter

Question 10

Blood & Nerve Supply of Kidney: Abundantly supplied with

Answer 10

• blood vessels

- receive 25% of resting cardiac output via renal arteries

Question 11

Functions of different capillary beds:

Answer 11

1. glomerular capillaries
2. peritubular capillaries
3. vasa recta

Question 12

glomerular capillaries:

Answer 12

• where filtration of blood occurs

- vasoconstriction & vasodilation of afferent & efferent arterioles produce large changes in renal filtration

Question 13

peritubular capillaries:

Answer 13

carry away reabsorbed substances from filtrate

Question 14

vasa recta:

Answer 14

supplies nutrients to medulla without disrupting its osmolarity form

Question 15

Blood & Nerve Supply of Kidney: regulate blood flow & renal resistance by altering arterioles

Answer 15

Sympathetic vasomotor nerves

Question 16

Blood Vessels around the Nephron:

Answer 16

Glomerular capillaries

Efferent arterioles

Question 17

Glomerular capillaries are formed between

Answer 17

the afferent & efferent arterioles

Question 18

Efferent arterioles give rise to

Answer 18

the peritubular capillaries and vasa recta

Question 19

The Nephron:

Answer 19

1. Renal corpuscle
2. Renal tubule
3. Collecting ducts and papillary ducts

Question 20

Renal corpuscle =

Answer 20

site of plasma filtration

Question 21

Renal corpuscle: 2 components

Answer 21

1. glomerulus is capillaries where filtration occurs

2. glomerular (Bowman’s) capsule is double-walled epithelial cup that collects filtrate

Question 22

Renal tubule=

Answer 22

• proximal convoluted tubule
• loop of Henle dips down into medulla
• distal convoluted tubule

Question 23

Collecting ducts and papillary ducts:

Answer 23

drain urine to the renal pelvis and ureter

Question 24

Cortical Nephron:

Answer 24

• 80-85% of nephrons are cortical nephrons

- Renal corpuscles are in outer cortex and loops of Henle lie mainly in cortex

Question 25

Flow of Fluid through a Cortical Nephron:

Answer 25

Glomenular capsule --> Proximal convoluted tubule --> Descending limb of the loop of Henle --> Ascending limb of the loop of Henle --> Distal convoluted tubule

Question 26

Juxtamedullary Nephron:

Answer 26

- 15-20% of nephrons are juxtamedullary nephrons - Renal corpuscles close to medulla and long loops of Henle extend into deepest medulla: excretion of dilute or concentrated urine

Question 27

Flow of Fluid through a Juxtamedullary Nephron:

Answer 27

Glomenular capsule --> Proximal convoluted tubule --> Descending limb of the loop of Henle --> Thin Ascending limb of the loop of Henle --> Thick ascending limb of the loop of Henle --> Distal convoluted tubule

Question 28

Histology of the Nephron & Collecting Duct:

Answer 28

- Single layer of epithelial cells forms walls of entire tube - Distinctive features due to function of each region

Question 29

Distinctive features due to function of each region:

Answer 29

microvilli cuboidal versus simple hormone receptors

Question 30

Structure of Renal Corpuscle:

Answer 30

Bowman’s capsule | Glomerular capillaries

Question 31

Structure of Renal Corpuscle:Bowman’s capsule

Answer 31

- surrounds capsular space 1. podocytes 2. simple squamous

Question 32

podocytes cover

Answer 32

capillaries to form visceral layer

Question 33

simple squamous cells form

Answer 33

parietal layer of capsule

Question 34

Glomerular capillaries arise from what and form what?

Answer 34

afferent arteriole & form a ball before emptying into efferent arteriole

Question 35

capsule space is where

Answer 35

filtrate accumulates

Question 36

Number of Nephrons:

Answer 36

1. Remains constant from birth | 2. If injured, no replacement occurs

Question 37

any increase in size of kidney is

Answer 37

size increase of individual nephrons

Question 38

Dysfunction is not evident until function:

Answer 38

declines by 25% of normal

Question 39

Removal of one kidney causes

Answer 39

enlargement of the remaining until it can filter at 80% of normal rate of 2 kidneys