Anatomy And Physiology Of The Kidney Flashcards
What are the functions of the kidneys?
- Water, electrolyte, and acid-base balance
- Hormone secretion
- Red cell production
- Control of BP
Are the kidneys retroperitoneal or intraperitoneal?
Retroperitoneal
Where are the kidneys located?
In the paravertebral space
How does the position of the right kidney compare to the left?
The right is slightly lower than the left
What is the average length of the kidney at birth?
4.5-5.5cm
How big are adult kidneys?
10-11.5cm in length, 5-7cm in width
What is the anterior surface of the kidney in contact with?
The duodenum on the right side, and the pancreas on the left
What is in contact with the inferior pole of the kidney?
Variable portions of the colon
What is the relationship between the spleen and the kidney?
On the left side, the spleen wraps the anterolateral aspects of the upper half of the kidney
What is the relationship between the ribs and the kidney?
The 12th rib and a portion of the 11th rib cover the upper third of the posterior surface of the left kidney
The 12th rib may touch the upper pole of the right kidney
What is the outer surface of the kidney covered by?
A thin but firm capsule
What does the anatomical position of the kidney explain clinically?
The retroperitoneal approach for renal biopsy, and the choice of lower pole of the right kidney
What are nephrons?
The ultrastructural units of the kidney
How many nephrons are in each kidney?
Around a million
What does the nephron comprise of?
A glomerulus connected to a tubule, which drains into a collecting duct.
What happens to the collecting ducts of the nephrons?
They join and drain into the calyces at the renal pyramids
What structure in the nephron generates ultrafiltrate?
Glomerulus
How does the glomerulus generate ultrafiltrate?
Through ultrafiltration of the blood brought in by the afferent arterioles
What happens to the ultrafiltrate generated by the glomerulus?
It accumulates in the Bowman’s space, and then traverses the tubules
What happens to the ultrafiltrate in the tubules?
It is further modified into the final urine
What happens during passage of tubular fluid down the renal tubule?
Solutes are reabsorbed by the highly selective transport mechanisms
What % of CO does renal blood flow comprise?
25%
What % of the renal blood flow goes into the peritubular circulation?
80%
What happens to blood in the peritubular circulation?
It receives solutes from the PCT
What solutes are reabsorbed from the PCT into the peritubular circulation?
- Glucose
- Amino acids
- Sodium
- Chloride
- Potassium
- HCO3
What happens to the remaining 20% of the renal blood flow?
It enters the juxtaglomerular apparatus
What happens to blood in the juxtaglomerular apparatus?
It undergoes ultrafiltration in the glomerulus
What is filtered out of the blood at the glomerulus?
- Glucose
- Amino acids
- Anions
- Cations
- Proteins <20 kilodaltons
- Urea
What is the first part of the glomerulus?
Proximal convuluted tubule
What is the importance of the PCT?
It is the major site for reabsorption
What % of glucose is reabsorbed in the PCT?
99%
What does bicarbonate reabsorption at the PCT affect?
Renal acid-base homeostasis
What comes after the PCT?
The loop of Henle
What is the loop of Henle the major site of?
Urine concentration
What are the parts of the loop of Henle?
- Thin descending limb
- Thick ascending limb
What comes after the loop of Henle?
Distal convoluted tubule
What happens in the DCT?
Further sodium chloride and water reabsorption
What comes after the DCT?
Collecting tubule
What happens in the DCT and CT?
Further sodium chloride and water reabsorption
What controls the reabsorption of NaCl and water in the DCT and CT?
Vasopressin and aldosterone
