Urinary System

Question 1

Functions of the kidney and urinary tract

Answer 1

1. Maintain water and electrolyte homeostasis, body fluid osmolarity and acid-base balance
2. Excrete toxic metabolic waste products (mainly urea and creatinine)
3. Act as an endocrine gland, producing renin and erythropoietin

Question 2

What functions do the urinary tract accomplish and how does it do this ?

Answer 2

1. Maintain water and electrolyte homeostasis, body fluid osmolarity and acid-base balance
2. Excrete toxic metabolic waste products (mainly urea and creatinine)

Does this by the production, storage and voiding of urine

Question 3

Kidney gross structure - shape and location

Answer 3

Kidney bean shaped in upper retroperitoneal area

Question 4

Kidney gross structure- hilum

Answer 4

Entry of renal artery and exit of renal vein and ureter

Question 5

Name structures going towards kidney from ureter

Answer 5

Renal pelvis, major calyces and minor calyces

Question 6

What are main two areas of kidney called

Answer 6

Cortex and medulla

Question 7

Medulla is divided into what

Answer 7

Medullary pyramids

Question 8

Each medullary pyramid and it’s associated cortical tissue is considered what?

Answer 8

A lobe of the kidney

Question 9

What is the kidney covered by?

Answer 9

Fibrous capsule

Question 10

What are medullary rays?

Answer 10

Collection of collecting ducts and straight segments of the proximal and distal convoluted tubules

Question 11

Where in the kidney are the medullary rays found?

Answer 11

The cortex

Question 12

What is the nephron?

Answer 12

The basic functional unit of the kidney

Question 13

What is the nephron composed off?

Answer 13

The renal corpuscle and renal tubules

Question 14

What is the principal role of the renal corpuscle?

Answer 14

Production and collection of glomerular filtrate

Question 15

What is the renal corpuscle composed off?

Answer 15

Glomerulus and Bowman’s capsule

Question 16

What is the glomerulus

Answer 16

Tuft of capillaries

Question 17

What is the Bowman’s capsule

Answer 17

Cup of simple squamous epithelium at the blind end of the nephron which the capillaries invaginate into

Question 18

What supplies the tuft of capillaries?

Answer 18

Afferent arterioles

Question 19

What drains the tuft of capillaries?

Answer 19

The efferent arterioles

Question 20

How many cell layers separate the blood from the glomerular filtrate and what are their names

Answer 20

Two

Capillary endothelium and specialised epithelium (lies ontop of glomerular capillaries)

• these epithelia cells are called podocytes

Question 21

What is a special feature of the endothelium?

Answer 21

It is fenestrated with pores

Question 22

What is a special feature of the podocytes?

Answer 22

Have interdigitating cell processes forming filtration slits

Question 23

What cells are scattered in the renal corpuscle that produce a connective tissue core and what is this core called?

Answer 23

Mesangial cells

Mesangium

Question 24

What are the functions of mesangial cells?

Answer 24

Support and removal of debris

Question 25

There are two poles in the renal corpuscle what are these two poles called?

Answer 25

Vascular pole and urinary pole

Question 26

Podocytes are said to have what appearance ?

Answer 26

Lightly coloured and their cell processes produce a saw tooth appearance

Question 27

The glomerular filter has 3 components

Answer 27

Fenestrated endothelium of capillary wall Thick basement membrane Filtration slits between pedicels

Question 28

What is the role of the proximal convoluted tubule?

Answer 28

Reabsorption of water, proteins, amino acids, carbohydrates and glucose

Question 29

What percentage of sodium and water is reabsorbed by the PCT

Answer 29

70%

Question 30

What else is reabsorbed by the PCT?

Answer 30

Almost all glucose and amino acids

Question 31

Principle Role of Loop of Henle

Answer 31

Creation of hypertonic environment in medulla

Question 32

What is the Vasa recta?

Answer 32

Loops of thin walled blood vessels that dip down into the medulla from above and then climb back up the cortex

Question 33

Structures in the outer medulla

Answer 33

Collecting ducts Blood vessels of vasa recta Thin loop of Henle Proximal and Distal staight tubules

Question 34

Principle Role of the DCT

Answer 34

Acid-base and water balance | Absorption of water, Na and bicarbonate, excretion of K and H ions

Question 35

Which is smaller DCT or PCT

Answer 35

DCT

Question 36

Which has a clearer lumen PCT or DCT

Answer 36

DCT - only have sparse microvilli unlike PCT

Question 37

What does the hormone aldosterone do?

Answer 37

Controls the reabsorption of Na+ in the DCT

Question 38

What secretes aldosterone?

Answer 38

Adrenal cortex

Question 39

What controls the secretion of Aldosterone ?

Answer 39

Renin-angiotensin system

Question 40

A greater Na+ and water retention causes....

Answer 40

Increase in blood pressure

Question 41

Role of collecting ducts

Answer 41

Controlled reabsorption of water under the control of ADH

Question 42

What hormone increase the permeability of collecting ducts to water and where is it secreted from?

Answer 42

Anti-diuretic hormone ( vasopressin) from posterior pituitary

Question 43

What type of urine results in the presence of ADH

Answer 43

Concentrated ADH = high permeability in medulla, because of the high salt content in the surrounding tissue, water passes out of the lumen

Question 44

What is the Juxtaglomerular apparatus?

Answer 44

Specialized region formed at the site where the distal convoluted tubule passes adjacent to the vascular pole of the same renal corpuscle that forms part of its own nephron

Question 45

The Juxtaglomerular apparatus is made up of three compartments ...they are ?

Answer 45

The macula densa The Juxtaglomerular cells The extraglomerular mesangial cells (lacis cells)

Question 46

Info on macula densa

Answer 46

On side of DCT nearest the afferent arteriole the cells of the DCT are taller, crowded together and the nuclei are intensely stained. Believe to have a function in sensing sodium content of fluid in the DCT

Question 47

Info on Juxtaglomerular cells

Answer 47

Modified smooth muscle cells in the wall of afferent arterioles. These cells contain/excrete renin, initiating the renin-angiotensin system.

Question 48

Info on extraglomerular cells (lacis cells )

Answer 48

Modified mesangial cells extending outside the renal corpuscle. They contact macula densa and are continuous with mesangial cells inside renal corpuscle.

Question 49

Direction of urine flow from renal papila (where it is produced)

Answer 49

Collected in minor caylx, flows into major caylx, ureter and then into bladder . During voiding it flows into the urethra and exits the body

Question 50

What are the conducting parts of the urinary tract lined with?

Answer 50

Transitional epithelium or urothelium - stratified

Question 51

Cells at lumen of urinary tract are called ?

Answer 51

Umbrella cells -domed

Question 52

Two reasons for specialised epithelium of urine tract

Answer 52

1. Variability in thickness of cells represents different states of distension 2. Special surface structures are to provide a highly impermeable barrier

Question 53

Lumen of the ureter has how many layers of smooth muscle

Answer 53

2 - an inner longitudinal layer and an outer circular layer

Question 54

Near bladder how many layers of smooth muscle?

Answer 54

3 - another outer layer of longitudinal muscle is present

Question 55

What do the smooth muscle layers in the bladder form?

Answer 55

The detrusor muscle

Question 56

What is the detrusor muscle responsible for?

Answer 56

Micturition

Question 57

In females what does the epithelium. Of the urethra change from ?

Answer 57

Transitional epithelium to stratified squamous near the surface of body