1.2 anatomy of the urinary system Flashcards
What are the main functions of the kidney?
Excretion
Regulation
Endocrine
Matebolism
What is the regulatory functions of the kidneys?
Body fluid volume and ionic compounds
Homeostasis
Acid-base balance (DCT)
What is the endocrine function of the kidney?
Synthesis of:
renin (blood pressure and sodium balance),
erythropoietin (erythrocyte production)
prostaglandins (involved in regulation of renal function)
What is the metabolic role of the kidneys?
Vitamin D is metabolized to its active form, impacting calcium absorption.
Major site for catabolism of low-molecular-weight proteins. Including:
• Insulin
• Parathyroid hormone
• Calcitonin
Where are the kidneys located?
Retroperitoneum on the posterior abdominal wall, either side of the vertebral column. Located between the t12 and L3 vertebrae, with the hilum roughly at L1
Why is the left kidney higher up than the right?
Because the liver pushes the right kidney downwards
How large is a normal kidney?
11cm long x 6cm wide
140g
What layers surround the kidney?
From proximal to distal: Renal capsule Perirenal fat Renal fascia Pararenal/paranephral fat
Describe the blood supply to the kidneys?
Renal veins drain directly into the IVC
Abdominal aorta branches off left and right renal arteries.
Left renal vein passes anterior to the aorta.
Right renal artery runs behind the IVC
Renal arteries usually divide to from an anterior and posterior branch
What are the 2 common types of nephrons? Which is more common?
Cortical nephron (85%) Juxtamedullary nephron (15%)
How do juxtamedullary nephrons vary from cortical nephrons?
Juxtamedullary nephrons have longer loops of henle that descend into the medulla of the kidney, allowing more water to be reabsorbed.
What are the 2 components of a renal corpuscle?
Glomerulus
Bowmans capsule
What are peritubular capillaries?
Capillaries that surround the cortical nephron and the top of the juxtamedullary nephrons
What are arcuate arteries?
Small Arteries in the kidney that give off smaller branches to supply nephrons
What surrounds the loop of henle?
The vasa recta, a capillary network
What surrounds the glomerulus within the bowmans capsule?
Podocytes
Extraglomerular mesangial cells
What is the function of extraglomerular mesangial cells?
Pass messages
Secrete substances
Support the capillary network
What is the juxtaglomerular apparatus?
Formed from the macula densa cells in the DCT and the granular cells lining the afferent and efferent arterioles.
Why is it important that the DCT lies in close proximity to the renal corpuscle?
So that the macula densa cells lie close to the granular cells and can send signals.
What is the function of the juxtaglomerular apparatus?
To regulate flow of blood through the kidney based on composition of the filtrate.