Histology

Question 1

What are the functions of the kidneys and urinary tract

Answer 1

Maintain water and electrolyte homeostasis, body fluid osmolarity and acid-base balance
Excrete toxic metabolic waste products - urea, creatinine etc
Act as an endocrine gland - renin and erythropoietin

Question 2

What hormones does the kidney release

Answer 2

Renin - enzyme involved in BP control

Erythropoietin - related to maintenance and production of RBC

Question 3

What covers the kidney

Answer 3

Strong capsule of dense collagen fibres

Question 4

How is the medulla divided

Answer 4

Into 8-18 medullary pyramids

Apices point toward the hilum - end in papillae which drain into the minor calyx

Question 5

What is a nephron

Answer 5

Basic functional unit of the kidney

Composed of renal corpuscle and the tubules

Question 6

What is the function of the renal corpuscle

Answer 6

Production and collection of the glomerular filtrate

Question 7

What forms the renal corpuscle

Answer 7

Collection of capillaries called the glomerulus
Part of the nephron lined by squamous epithelium - forms a cup called Bowman’s capsule
The capillaries invaginate into the capsule

Question 8

What are podocytes

Answer 8

Specialised epithelial cells that lie on top of the glomerular capillaries
They have interdigitating, ‘feet-like’ processes that form slits for the filtrate to get through

Question 9

Describe the endothelium of the glomerular capillaries

Answer 9

It is fenestrated (has pores) to allow for easy fluid movement

Question 10

List the layers that filtrate from the glomerular capillaries must pass through to reach the nephron

Answer 10

Endothelium of the capillary
Thicker basal lamina
Podocyte processes

Question 11

What is the mesangium

Answer 11

Connective tissue core to the corpuscle formed by scattered mesangial cells
Involved in support and the removal of debris

Question 12

Glomerular filtrate is similar in volume to the amount of urine left at the end of the process

Answer 12

FALSE

Much greater as lots is reabsorbed in the rest of the system

Question 13

What is the function of the proximal convoluted tubule

Answer 13

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

Question 14

The proximal convoluted tubule has lots of microvilli - true or false

Answer 14

True

They increase the surface area for reabsorption

Question 15

How doe a proximal convoluted tubule appear on histology

Answer 15

Cross section has a fizzy inner border due to all the microvilli

Question 16

What type of cell lines the proximal convoluted tubule

Answer 16

Cuboidal epithelial cells

Question 17

Describe the structure and lining of the loop of Henle

Answer 17

Starts off wide and lined by cuboidal but becomes a very thin tube lined by squamous – becomes thick again when you reach the top of ascending limb

It starts in the cortex, dives down into the medulla and then up again

Question 18

What is the function of the loop of Henle

Answer 18

Creation of hyperosmotic environment in medulla

Very salty

Question 19

What are the vasa recta

Answer 19

Specialised blood vessels that follow the same path as the loop of Henle - dive down into medulla they head back up
They are designed not to disrupt the osmotic gradient in the loop

Question 20

What is the function of the distal convoluted tubule

Answer 20

acid-base and water balance (absorption of water, Na and bicarbonate, excretion of K and H ions).

Question 21

What controls reabsorption in the distal convoluted tubule

Answer 21

Aldosterone which is released by the adrenal cortex

Question 22

Where is the collecting duct found

Answer 22

It connects to the distal tubule of the nephron and then dives back down to through the medulla to the tip of the pyramid
Here, urine drips off into the minor calyx

Question 23

What hormone acts in the collecting ducts

Answer 23

ADH

It increases permeability of the duct to cause more reabsorption of water

Question 24

What type of epithelium lines the urinary tract

Answer 24

Transitional epithelium
AKA urothelium
highly specialised to form an impenetrable barrier – stops any components of urine getting back into the body
Have the capacity to move over each other and thicken the lining

Question 25

Who has the longer urethra - men or women

Answer 25

Men
Male urethrea is 20cm
Female is 3-5cm

Question 26

What lines the female urethra

Answer 26

Transitional epithelium that becomes stratified squamous near the termination

Question 27

What lines the male urethra

Answer 27

In prostatic it is transitional
In membranous it changes to stratified columnar
In penile it is stratified columnar and becomes stratified squamous near the tip