Lecture 28: Structure of kidney

Question 1

What percentage of males vs females bodies is water?

Answer 1

Males = 60% (due to more muscle tissue)

Females = 55% (due to more adipose tissue)

Question 2

What percentage of our body’s water is in cells (intracellular) and what percentage is out of cells (extracellular)?

Answer 2

2/3 of our body’s water is inside the cells (intracellular)

1/3 of our body’s water is outside the cells (extracellular)

Question 3

How does the urinary system maintain balance?

Answer 3

By filtering the blood and expelling:
– Excess water
– Excess salts
– Wastes of metabolism
– Many toxins and drugs

Question 4

Is urine pH tightly regulated?

Answer 4

Urine pH is not tightly regulated (pH ~4.6 - 8) and is influenced by what is excreted

This helps maintain a stable pH of blood which is much more important

Question 5

What would be abnormal to find in urine?

Answer 5

*Large proteins (too big to be filtered)
*RBC (too big to be filtered)
*Glucose (filtered, but completely reabsorbed)

Question 6

What does the urinary system need to be effective? Basically describe the whole process

Answer 6

• Delivery system for blood
• Selective filtration system
• Filtrate recovery mechanism
• System to return recovered, filtered fluid to body
• System to remove filtrate from body
• Protection
• Ability to communicate with relevant parts of the body
• Adaptable to meet the body’s changing needs

Question 7

What are the main components of the urinary system?

Answer 7

• 2 kidneys
• 2 ureters
• Urinary bladder
• Urethra

Question 8

What does the structure of the kidneys allow for?

Answer 8

• Blood to be brought into close proximity with the nephron, for filtering
• Blood that has been filtered to leave the kidney
• A pathway for urine to be removed from the kidney, stored and then excreted
• Protection

Question 9

Where are the kidneys?

Answer 9

• T12-L3
• 11th and 12th ribs
  Retroperitoneal: Located on posterior abdominal wall, covered on anterior side by peritoneum

Question 10

What does the hilum of the kidney contain?

Answer 10

• renal blood vessels, lymphatics, nerves and the ureter

Question 11

What are the three main regions of the kidneys?

Answer 11

cortex
medulla
pelvis

Also has a Fibrous capsule

Question 12

What is the inner medulla?

Answer 12

• divided into pyramids
• each medullary pyramid ends in a papilla

Question 13

What is the outer cortex?

Answer 13

• continuous layer
• also forms renal columns (between pyramids)

Question 14

How many lobes are in a normal kidney?

Answer 14

5-11 functional lobes per kidney

Question 15

What is a kidney lobe largely made up of?

Answer 15

Made up largely of nephrons - tiny tubes that filter from blood and create urine

Question 16

How does urine drain from the kidney?

Answer 16

Urine travels into: papilla → minor calyx →major calyx → renal pelvis → ureter

Question 17

Name three structures that provide external protection for the kidneys:

Answer 17

11th and 12th ribs
Renal fat pad
Fibrous capsule

Question 18

Where does filtration of the blood take place?

Answer 18

Filtration occurs in the glomerulus (cortex of the kidney).

Question 19

How is blood supplied to the kidneys to be filtered?

Answer 19

Abdominal aorta
→ renal artery
→ Series of arteries
→ afferent arteriole
→ glomerular capillary

Question 20

How is blood supply moved away from the kidneys after being filtered?

Answer 20

Glomerular capillary
→ efferent arteriole
→ peritubular capillaries
→ series of veins
→ renal vein
→ inferior vena cava

Question 21

What nerves control the kidneys and what is their role?

Answer 21

• Innervation is from a network of autonomic nerves and ganglia called the renal plexus
• Sympathetic nerves act to adjust diameter of renal arterioles and thus regulate blood flow.

Question 22

What are the three main roles of nephrons?

Answer 22

• Filters blood
• Selectively reabsorbs or secretes
• Produces urine

Question 23

Which of the following structures does
NOT pass through the hilum of the
kidney?
A. Renal vein
B. Urethra
C. Lymphatics
D. Renal nerves
E. Renal artery

Answer 23

B

Question 24

Which kidney is most inferior, and why?

Answer 24

The right kidney is lower than the left kidney due to the presence of the liver above