Urinary 1 Flashcards
What are the main function of the urinary system?
- cleansing the blood
- regulation of pH
- regulation of BP
- regulate [solutes] in the blood
- erythropoietin production ([RBC])
- final synthesis step in vitamin D activation (calcidol to calitrol)
T/F: Kidneys are poorly vascularized
False, they are highly vascularzed, receiving 20-25% of CO
Definition:
Outer region of the kidney
renal cortex
Definition
Medulla
Inner region of the kidney
What do the afferent artiroles supply blood to?
Glomerulus capillaries (Bowman’s capsule)
What do efferent arterioles form?
A capillary network around the distal portions off the nerphron tubule (peritubule capillaries and vasa recta)
What is found in the cortex?
All renal corpuscles and the distal and proximal convoluted tubules
Definition:
Cortical nephrons
Nephrons with short loop of henle that barely dips beyond the cortex
Definition:
Nephrons with long loops of henle that extend deep into the medulla
Juxtamedullary nephrons
What cannot filter through the fenstrations of the Bowman’s capsule?
Blood cells or large proteins
Do positively or negatively charged substances pass more readily through the fenestrations?
Positively as the proteins associated the fenestrations pores are negatively charged
What are the characteristics of filtrate?
- does not contain any cells or large proteins (like RBC’s and albumin)
- has a slight predominance of positively charged substances (Na+ and K+)
Describe the structure of the proximal convoluted tubule.
Simple cuboidal cells with priminent microvilli forming a brush border
What is the purpose of the brush border?
creates a large surface area to maximize the reabsorption and secretion of solutes
What type of cells make up the thick portions of the loop of henle? Thin?
Thick: simple cuboidal epithelium
Thin: Simple squamous epithelium
What does the loop of henle have different thickness?
Allows to different permeabilites for solutes and water
How does the DCT differ from the PCT?
Shorter, and is less active in absorption/secretion so there are lkess microvilli and the apical surface and no brush border
What does the juxtaglomerular apparatus contain?
Macula densa and juxtaglomerular cells
What does the juxtaglomerular apparatus do?
monitors composition (chemoreceptors) and rate of fluid flowing (mechano-baroreceptors) through the DCT
What happens when the osmolarity of the filtrate is too high (hyperosmotic)?
Juxtaglomerular cells will contract, dec the glomerular filtration rate so less plasma is filtered, leading to less urine formation and greater rentention of fluid
T/F: a second function of the macula densa cells is to regulate renin release from the juxtaglomerular cells of the afferent arteriole
True
What does angiotensin II stimulate? What does this cause?
release of aldosterone from the adrenal cortex
aldosterone stimulates Na reabsorption in the kidney resulting in water retention and inc BP
T/F: angiotensin II is a systemic vasocodilator that dec BP
False.
Vasconstrictor that inc BP
What do natriuretic hormones do?
Stimulate the kidneys the excrete Na by inhibiting aldosterone release
