Urinary System

Question 1

How is water gained in the body?

Answer 1

• food
• drink
• metabolic water

Question 2

How is water lost?

Answer 2

• urination
• defacation
• evaporation (breath and sweat)

Question 3

Function: kidneys

Answer 3

Produce urine

Question 4

Function: ureters

Answer 4

Transport urine to bladder

Question 5

Function: bladder

Answer 5

Stores urine

Question 6

Function: urethra

Answer 6

Passes urine to the outside

Question 7

Function: renal cortex

Answer 7

Filters the blood

Question 8

Function: renal medulla

Answer 8

Concentrates the filtrate

Question 9

Where does urine enter the bladder from?

Answer 9

From below

Question 10

How does urine get transported from kidneys to bladder?

Answer 10

Urine from renal pelvis stretches ureters

Peristalsis wave

Question 11

Involuntary control of urination

Answer 11

• stretch receptors in bladder wall activated
• signals travel to sacral spinal cord
• motor nerves cause contraction of bladder and relaxation of internal sphincter

Question 12

What are the parts of the nephron?

Answer 12

Renal corpuscle (glomerulus and bowmans capsule)
Proximal convoluted tubule
Loop of Henle
Distal convoluted tubule
Collecting duct

Question 13

Flow of filtrate

Answer 13

Nephron - papillary duct - minor calyx - major calyx - renal pelvis

Question 14

What is glomerular filtration?

Answer 14

Creates a plasma like filtrate of the blood

Question 15

What is tubular reabsorption?

Answer 15

Removes useful solutes from the filtrate and returns them to the blood

Question 16

What is tubular secretion?

Answer 16

Removes additional wastes from the blood and adds them to the filtrate

Question 17

What is water conservation?

Answer 17

Removes water from the urine and returns it to the blood, concentrates filtrate

Question 18

Why does the afferent arteriose have a larger diameter than the efferent arteriole?

Answer 18

Generates a large hydrostatic pressure forcing solutes out of the blood and into the filtrate

Question 19

What three layers must something entering the filtrate pass through?

Answer 19

• endothelium of glomerular capillaries (filtration pores)
• basement membrane
• filtration slits between the podocyte cell extensions

Question 20

Bowmans capsule structure

Answer 20

• parietal layer: simple squamous epithelium
• visceral layer: podocytes which wrap around the capillaries
• capsular space: between two layers, filtrate collects here

Question 21

What does not pass through the filter?

Answer 21

• blood cells
• plasma proteins
• large anions

Question 22

What is proteinuria?

Answer 22

Protein in urine

Question 23

What is hematuria?

Answer 23

Blood in urine

Question 24

Proximal convoluted tubule structure and function

Answer 24

• simple cuboidal epithelium with microvilli

- absorption

Question 25

Thin loop of henle structure and function

Answer 25

- simple squamous epithelium | - very permeable to water so water moves out

Question 26

Thick loop of henle structure and function

Answer 26

- simple cuboidal epithelium with many mitochondria | - active transport of salts out of filtrate

Question 27

Distal convoluted tubule epithelium

Answer 27

Simple cuboidal with no microvilli

Question 28

Transport maximum

Answer 28

Renal threshold

Question 29

What does ADH do and where does it act?

Answer 29

Increases water permeability of DCT and CD

Question 30

What is the stimulus for ADH?

Answer 30

- increase of blood osmotic pressure | - decreases in blood volume

Question 31

What is diabetes insipidus?

Answer 31

Lack of ADH

Question 32

What is the function of the change in concentration (osmotic pressure) from cortex to medulla in humans?

Answer 32

- concentration gradient increases from 300mOsmol/L to 1200mOsmol/L across the medulla - when filtrate travels through the medulla, water in the CD can be pulled out of the filtrate by the higher osmotic pressure in the sureounding interstitial fluid providing that the collecting duct is permeable to water

Question 33

What does the anatomy of the human kidney (cortical length vs medullary length) tell you about the type of environment that humans evolved in?

Answer 33

- Human have a quite deep medulla - humans can concentrate their urine - humans can to some extent deal with fairly dry environments, but are not as well adapted as desert mammals - fossils have been found near lakes (access to water) but humans would have had to move away from water source to hunt and collect food

Question 34

How does ADH reduce the volume of urine?

Answer 34

- increases permeability of DCT and CD to water - water is able to move along its concentration gradient out of the nephron - this concentrates urine, and hence decreases volume

Question 35

How does alcohol increase the volume of urine?

Answer 35

- drop in ADH decreases permeability of CD and DCT to water - more water is retained in the filtrate - increases volume of urine