H13 - Urinary System Flashcards
What is the functions of the Kidney and Urinary Tract ?
- Maintain water and electrolyte homeostasis, body fluid osmolarity and acid-base balance.
- Excrete toxic metabolic waste products (mainly urea and creatinine).
- Act as an endocrine gland, producing renin and erythropoietin.
What is the kidney surrounded in?
thin but strong capsule of dense collagen fibres.
What is the site of entry of renal artery and exit of renal vein and ureter?
hilum
What is the basic functional unit of the kidney?
nephron
what is the outer capsule of the kidney continuous with?
tissue that lines the renal sinus
what are medullary rays?
collections of collecting ducts and the straight segments of the proximal and distal convoluted
what is the nephron composed of?
renal corpuscle and renal tubules.
what is the role of the renal corpuscle?
production and collection of glomerular filtrate.
what is the role of the proximal convoluted tubule?
reabsorption of water, proteins, amino acids, carbohydrates and glucose.
what is the role of the loop of henle?
creation of hypertonic environment in medulla.
what is the role of the distal tubule?
acid-base and water balance (absorption of water, Na and bicarbonate, excretion of K and H ions).
What cells seperate the blood from the glomerular filtrate?
podocytes
What is formed by the glomerulus and the Bowman’s Capsule?
Renal Corpuscle
What cells are found between endothelial cells and the basal lamina, and control filtration rate and remove debris?
Mesangial
what are the three parts of the glomerular filter?
- The fenestrated endothelium of the capillary wall.
- The thick basement membrane (shared by endothelium and podocyte).
- The filtration slits between pedicels
What type of cells is the proximal convoluted tubule lined with?
Simple Cuboidal Epithelium with Microvilli
what are the loops of thin walled blood vessels that dip down into the medulla from above and then climb back up to the cortex
vasa recta
What type of cells is the distal convoluted tubule lined with?
Simple Cuboidal Epithelium (no microvilli)
what controls reabsorption of Na+ in the distal tubule?
aldosterone which is secreted by the adrenal cortex
What senses Na+ content of the fluid in the distal convoluted tubule?
macula densa
What are modified smooth muscle cells in the wall of the afferent arteriole that contain and excrete renin?
Juxtaglomerular Cells
What specialised epithelium lines the urinary tract and is stratified (3-6 cell layers)
Urothelium (Transitional Epithelium)
what are the 3 components of the juxtaglomerular apparatus?
Macula densa
Juxtaglomerular cells
Extraglomerular mesagnial cells
How is the aldosterone secretion controlled to result in greater sodium and water retention therefore increasing blood pressure?
Renin-angiotensin system
