4.4_1 Renal I Flashcards
Regulation of ion concentrations in body fluids
Maintains blood osmolarity by retaining water (ADH)
Regulation of volume of body fluids and thus blood pressure
Managed by retention of essential ions (Na+, Cl-, K+, ca2+)
RAAS
Regulation of blood pH (Assisting the lungs)
Kidney cells express carbonic anhydrase [H+] via CO2 and HCO3-
Elimination of waste products
Metabolic waste: mainly urea
Xenobiotic waste: a foreign molecule
Renal artery directs ____% of CO to the kidneys
22
How many times a day is your 5L of blood filtered?
About 36
Two layers to the kidney
Renal cortex
Renal medulla
Renal cortex (relation to blood)
Isotonic to blood
Renal medulla (relation to blood)
Very salty, hypertonic to blood
All nephrons begin in the…
Cortex
Two types of nephrons in the kidney
Cortical
Juxtamedullary
Cortical nephrons
85%
Have very short loops of Henle, do not leave cortex
Juxtamedullary nephrons
Start in the cortex, have long loops of Henle that penetrate deep into the medulla
From the _____ to the _______, the kidneys are trying to capture something back from the tubular fluid
Proximal convoluted tubule
Collecting duct
Fluid is called filtrate in the..
Capsular space
Fluid is called tubular fluid in the..
PCT-Collecting duct
Fluid is called urine in the..
Papillary duct-urethra
3 Processes resulting in urine formation
1) Glomerular Ultrafiltration
2) Tubular Reabsorption
3) Tubular Secretion
Glomerular ultrafiltration
Blood plasma enters tubules as filtrate
Tubular reabsorption
Filtrate moved back into blood in tubules
Tubular secretion
Substances transported from blood to tubules
Fenestrated Capillaries
Leaky endothelial cells (have holes)
Glomerular Podocytes
Provide a selective barrier for ultrafiltration
Juxtaglomerular Apparatus
Monitors and regulates whole blood volume and blood pressure throughout the entire body
Renal corpuscle
Filtration membrane comprised of fenestrated capillaries and glomerular podocytes
Filtration slits
In glomerular podocyte cells –> enable ultrafiltration
Why do diabetic’s kidneys start to fail?
Because it makes the muscles more rigid, which leads to higher BP and kidneys are very sensitive to chronic high BP
What does the filtrate include?
Water, glucose, amino acids, ions, urea, many hormones, vitamins B and C, ketones and very small amounts of protein
What is the main force drives ultrafiltration in glomerulus?
Hydrostatic pressure
What does the endothelium in the glomerulus block?
Formed elements
What does the basement membrane in the glomerulus block?
Large proteins
What do the filtration slits of the visceral layer in the glomerulus block?
Small proteins
What is not filterable by the glomerulus?
Proteins in plasma
Blood cells
Any large, bulky molecule
How do you calculate renal blood flow?
20 % of cardiac output
What flow really mattes when calculating glomerular filtration rate?
Only plasma flow
55% plasma
GFR
Volume of plasma filtrate that enters the capsular space per minute
What percentage of plasma gets forced out of blood?
19%
What percentage of what gets filtered is reabsorbed?
99%
Vasa recta
Blood vessels around loop of Henle
Peritubular capillaries
Blood vessels associated with peritubular capillaries
Afferent arteriole
Incoming, larger diameter
Efferent arteriole
Outflow from corpuscle, smaller diameter
Increased vascular resistance creates…
1) High hydrostatic pressure upstream in fenestrated glomerular capillaries
2) Low hydrostatic pressure downstream in peritubular and vasa recta capillaries
_______ have lowest hydrostatic pressure in entire body
Peritubular capillaries
Net filtration pressure favors….
Filtrate entry into tubules (some things go in and some go out)
