Lecture 28: Structure of kidney Flashcards
What percentage of males vs females bodies is water?
Males = 60% (due to more muscle tissue)
Females = 55% (due to more adipose tissue)
What percentage of our body’s water is in cells (intracellular) and what percentage is out of cells (extracellular)?
2/3 of our body’s water is inside the cells (intracellular)
1/3 of our body’s water is outside the cells (extracellular)
How does the urinary system maintain balance?
By filtering the blood and expelling:
– Excess water
– Excess salts
– Wastes of metabolism
– Many toxins and drugs
Is urine pH tightly regulated?
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
What would be abnormal to find in urine?
*Large proteins (too big to be filtered)
*RBC (too big to be filtered)
*Glucose (filtered, but completely reabsorbed)
What does the urinary system need to be effective? Basically describe the whole process
- 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
What are the main components of the urinary system?
- 2 kidneys
- 2 ureters
- Urinary bladder
- Urethra
What does the structure of the kidneys allow for?
- 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
Where are the kidneys?
- T12-L3
- 11th and 12th ribs
Retroperitoneal: Located on posterior abdominal wall, covered on anterior side by peritoneum
What does the hilum of the kidney contain?
- renal blood vessels, lymphatics, nerves and the ureter
What are the three main regions of the kidneys?
cortex
medulla
pelvis
Also has a Fibrous capsule
What is the inner medulla?
- divided into pyramids
- each medullary pyramid ends in a papilla
What is the outer cortex?
- continuous layer
- also forms renal columns (between pyramids)
How many lobes are in a normal kidney?
5-11 functional lobes per kidney
What is a kidney lobe largely made up of?
Made up largely of nephrons - tiny tubes that filter from blood and create urine
How does urine drain from the kidney?
Urine travels into: papilla → minor calyx →major calyx → renal pelvis → ureter
Name three structures that provide external protection for the kidneys:
11th and 12th ribs
Renal fat pad
Fibrous capsule
Where does filtration of the blood take place?
Filtration occurs in the glomerulus (cortex of the kidney).
How is blood supplied to the kidneys to be filtered?
Abdominal aorta
→ renal artery
→ Series of arteries
→ afferent arteriole
→ glomerular capillary
How is blood supply moved away from the kidneys after being filtered?
Glomerular capillary
→ efferent arteriole
→ peritubular capillaries
→ series of veins
→ renal vein
→ inferior vena cava
What nerves control the kidneys and what is their role?
- 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.
What are the three main roles of nephrons?
- Filters blood
- Selectively reabsorbs or secretes
- Produces urine
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
B
Which kidney is most inferior, and why?
The right kidney is lower than the left kidney due to the presence of the liver above
