Lecture 32: Overview of the urinary system

Question 1

What it the role of the kidneys?

How do they achieve this?

Answer 1

Is to maintain water and chemical balance in the body
This is achieved by expelling:
- excess water & salts
- wastes of metabolism and many toxins and drugs
= A high blood flow 1200mL/min through the kidneys is necessary for them to perform their tasks effectively.

Question 2

What are the major components of the urinary system?

Answer 2

2 kidneys = bean shaped organs
2 ureters = the ureters are tubes through which urine flows from the kidneys to the bladder
Urinary bladder= is the organ for the storage of urine
Urethra= is the tube which urine flows from the bladder to the outside world
Regulatory nerves and muscle work to regulate function

Question 3

Where are the kidneys located?

Answer 3

They are located btw T12-L3

• the left kidney is higher then the right, right is inferior bcs of liver
• the medial surface has a notch called the HILUM which is an entry/exist point for arteries, veins, lymphatics, nerves and ureters.
• located on posterior abdominal wall

Question 4

What is the outer layer of the kidney called?

What is its structure?

Answer 4

Outer layer = cortex

• continous layer
• makes up renal columns which lie between the medullary pyramids

Question 5

What is the inner layer of the kidney called?

What is its structure ?

Answer 5

Inner layer = medullar

• divided into 7 medullary pyramids
• each medullary pyramid empties urine into a papilla
• each medullary pyramids ends in a papilla

Question 6

What do the inner and outer layers of kidney form?

Answer 6

FORMS LOBES

• each medullary pyramid corresponds with an outer region of the cortex to form a lobe
• there are 5-11 lobes

Question 7

What does urine empty into?

• Describe the passage of urine

Answer 7

Urine drains from each papilla and collects in a calyx

• calyces (2 calyx) join to form renal pelvis
• pelvis narrows as it exits the hilum to become the ureter

Urine travels into:
papilla –> minor calyx –.> major calyx —> renal calyx —> ureter —> bladder

Question 8

How is blood supplied to the kidneys?

Answer 8

Blood supply to the kidneys is form the renal arteries which are branches of the abdominal aorta.
- once the renal arteries enter the kidneys (pass through hilum), they divide into five segmental arteries.

Question 9

Describe the blood supply pathway to the kidneys

Answer 9

• Renal arteries divide into five segmental arteries upon entering the hilum
• Each segmental artery then braces to form lobar arteries
• Between the lobes are interlobar arteries when form arcuate arteries
• arcuate arteries arch over the medullary pyramids and branch to interlobular arteries which penetrate the kidney cortex

Question 10

Describe the blood supply INTO the cortex

Describe blood supply AWAY from the cortex

Answer 10

INTO
interlobular artery —> afferent arteriole —-> glomerular capillary

AWAY
glomerular capillary —> efferent arteriole —-> peritubular capillaries

Question 11

How are the kidneys innervated?

- describe nerve supply to the kidney

Answer 11

Innervation is from a network of autonomic nerves and ganglia called the renal plexus
renal plexus = supplied by sympathetic nerve fibres
- renal plexus controls the level of vasoconstriction of the renal arterioles - adjusts diameter and thus regulates flow