W8- Lecture 42- Urinary system

Question 1

what are the kidneys?

Answer 1

Organs that excrete urine
Paired, bean-shaped organs located in the posterior abdomen
Lateral surface is convex; medial surface is concave - Hilum
Right kidney is lower than left (due to liver)
Capped by the adrenal glands - on top (endocrine system)

Question 2

where in the kidney would the find the renal pelvis, renal vein, renal artery and ureter?

Answer 2

the hilum

Question 3

which organs form the urinary tract ?

Answer 3

• Ureters (paired tubes)
• Urinary bladder (muscular sac)
• Urethra (exit tube)

Question 4

what are the three key functional roles of the urinary system?

Answer 4

Excretion

- Removal of waste from body fluids
- Occurs in kidneys – the nephron is the 	functional unit for this process

Elimination

- Storage of urine (bladder)
- Discharge of waste products 	(urination/micturition)

Homeostatic Regulation

- Blood plasma volume & pH
- Plasma ion concentrations
- Conservation of nutrients
- Elimination of toxins

Question 5

In the kidney what is the renal capsule?

Answer 5

Fibrous capsule that encases kidney and prevents infection

Question 6

In the kidney what is the renal fascia?

Answer 6

Outer layer of dense fibrous connective tissue that anchors the kidney

Question 7

In the kidney what is the perirenal fat ?

Answer 7

External to renal fascia + provides

Protection to kidneys

Question 8

what is the renal hilum ?

Answer 8

The renal hilum is the indented part of the kidney, on the medial surface

Point of entry

- Renal artery
- Renal nerves

Point of exit

- Renal vein
- Ureter

Question 9

In the kidney what is the cortex?

Answer 9

Granular superficial region.

Extends into medulla as renal columns

Question 10

In the kidney what is the medulla ?

Answer 10

Subcortex, composed of six to eighteen triangular renal pyramids, separated by renal columns

Question 11

make sure you can label a kidney

Answer 11

did you get all 10 ?
1- renal capsule
2- renal cortex
3- renal medulla
4- renal pyramids
5- renal columns
6- renal papilla
7- minor calyx
8- major calyx
9- renal pelvis
10- ureter

Question 12

where would you find renal papillae?

what are they ?

Answer 12

At the base of renal pyramids

Openings into the minor calyx that channel urine towards the renal pelvis

Question 13

what are the two types of renal nephrons ?

Answer 13

Cortical – Only just penetrating the medulla

Juxtamedullary – Reaching deep into the medulla

Question 14

what structures are included in the renal corpuscle within the nephron?

Answer 14

Glomerular (Bowman’s) capsulecup-shaped chamber

2. Glomerulus
   a network of capillaries

Question 15

what is the renal tubule ?
where does the renal tubule begin ?

length ?

Answer 15

long tubular passage in the nephron
begins at the renal corpuscle

about 50 mm long

Question 16

what is the Proximal convoluted tubule (PCT)?

made from ?

Answer 16

First segment of renal tubule

Simple cuboidal cells with microvilli on the luminal surface

Question 17

what is the nephron loop also known as ?

descending- location and structure
Ascending - location and structure

Answer 17

Loop of Henle

Descending limb (squamous) passes into medulla
Ascending limb (cuboidal) re-enters cortex and transitions into distal convoluted tubule (DCT)

Question 18

what is the Distal convoluted tube (DCT) ?
function
location

Answer 18

Empties urine into common collecting duct, leading to the papillary duct and renal papillae at the tip of the renal pyramid

Question 19

what epithelial linings does each of these compartments of the renal tubule?
PCT
nephron loop- descending + thin ascending
nephron loop- thick ascending
DCT
last part of DCT and the collecting duct

Answer 19

PCT=simple cuboidal epithelial cells with prominent brush borders of microvilli

nephron loop- descending + thin ascending= simple squamous epithelial cells

nephron loop- thick ascending =simple cuboidal to low columnar epithelial cells

DCT=simple cuboidal epithelial cells

last part of DCT and the collecting duct= simple cuboidal epithelium consisting of principle cells and intercalated cells.

Question 20

in the kidney what does the renal corpuscle include ?

what are the outer and inner layers formed of ?

Answer 20

glomerulus and Bowman’s capsule

Outer: Simple squamous epithelium
Inner: Specialised podocytes

Question 21

what are podocytes ?

Answer 21

Cells with processes adhering to basal lamina over fenestrated capillary endothelium

Question 22

Approximately% of systemic cardiac output flows through kidneys ?
does arterial flow differ to venous flow

Answer 22

25%

both follow similar paths

Question 23

what is the incidence of horseshoe kidney?

how is it discovered ?

Answer 23

Incidence 1 in 600 births.

Asymptomatic and discovered on imaging.

Question 24

what is the Ureter

Answer 24

Urine flows from renal pelvis through the ureter (1 per kidney) to the urinary bladder

Entrance into bladder is oblique

Ureters actively propel urine to bladder via peristalsis, in response to smooth muscle stretch

Question 25

describe the urether wall

Answer 25

Ureters have a tri-layered wall: -

Internal mucosa with a transitional epithelium called “urothelium”

Medial muscularis layer

Fibrous external connective tissue adventitia

Question 26

Urothelium(transitional epithelium)
permeability
layers

Answer 26

impermeable to salts and water

layers
superficial, intermediate and basal

Question 27

what is the bladder ?
location
storage capacity

Answer 27

Smooth muscle ‘sac’ that stores urine

Rests on pelvic floor (retro-peritoneal)

Stores approx 0.5 litres urine

As urine accumulates, the bladder expands without significant rise in internal pressure

Question 28

what three layers are within the bladder ?

Answer 28

The bladder has three layers:

Transitional epithelial layer (urothelium)

Muscle layer
-detrusor muscle

Adventitia

Question 29

what is the trigone within the bladder ?

clinical importance

Answer 29

Triangular area outlined by openings for the ureters and the urethra
Clinically important as infections tend to persist in this region

Question 30

length of urethra male v female

Answer 30

Length:

• Females: approx. 4 cm
• Males: approx. 20 cm

Question 31

describe the internal urethral sphincter?
control
location

Answer 31

Involuntary control

Located at bladder-urethra junction

Question 32

describe the External urethral sphincter
control
location
controlled by

Answer 32

• Voluntary control
• Passes through urogenital diaphragm
• Controlled by levator ani muscle, situated on the side of the pelvis

Question 33

Urinary tract infections
gender incidences/ why
usual pathogen
lead to

Answer 33

UTI are more common in females, due to the shorter urethra.

E. Coli is the usual pathogen involved.

UTI may lead to urethritis, cystitis (bladder inflammation) and infection of kidneys (pyelonephritis).