Renal System Flashcards
Net Filtration Pressure (NFP)
pressure that determines how much water and small dissolved solutes leaves the blood
NFP =
NFP = GBHP - CHP - BCOP
Glomerular Blood Hydrostatic Pressure (GBHP)
mechanical pressure between the afferent and efferent arterioles (pressure inside BV pushes the blood)
- within the glomerulus, drives the plasma filtrate from the capillaries of the glomerulus into the capsular space
Capsular Hydrostatic Pressure (CHP)
the pressure exerted on the plasma filtrate by the elastic recoil of the glomerular capsule
Blood Colloid Osmotic Pressure (BCOP)
The osmotic force of the proteins left in the plasma
(the proteins exert an increasing osmotic “pull” on the water in the plasma filtrate
What two forces filter fluid out?
Glomerular Capillary Hydrostatic Pressure
Bowmans Space Oncotic Pressure
What two forces oppose ultrafiltration?
Glomerular Capillary Oncotic Pressure
Bowmans Space Hydrostatic Pressure
What does the interaction between the podocytes and underlying capillaries do?
Enables filtration to take place that allows blood to be filtered (forms a filtration barrier)
What do the cells on the Distal Convoluted Tubule do?
Responsible for sensing how well a nephron is performing can tell afferent arteriole to constrict or dilate - slows down blood flow in glomerular capillaries
Podocytes
modifiied epithelium
visceral layer (inner)
What are the 3 layers of filtration on the capillaries in the Glomerulus?
Fenestrated endothelium (no rbc, but all sizes of proteins)
Basal Lamina (Medium + small proteins)
Slit membrane between Pedicels (small proteins)
Osmolality
measure of the osmotic pressure exerted by a solution across a perfect semi-permeable membrane compared to pure water
- a count of the number of dissolved particles in a set volume
Tonicity
the capability of a solution to modify the volume of cells by altering their water content
NaCL
low permeability
Urea
high permeability
exerts not much osmotic force
Proportions of Fluid in the body
1/3 Extracellular
2/3 Intracellular
Which ions have a higher concentration in the extracellular fluid?
Na+, Ca2+ , Cl-
Which ion have a higher concentration in the intracellular fluid?
K+
Two types of hormanal regulation of Glomerular Filtration Rate
Angiotensin II
Atrial Natriuretic Peptide (ANP)
Angiotensin II
(GFR)
Constricts the afferent and efferent arterioles
DECREASE IN GFR
What stimulates secretion of ANP?
Stretching of atria of heart
What stimulates Angiotension ll production?
Decreased BV or BP
Atrial Natriuretic Peptide (ANP
(GFR)
Relaxation of mesangial cells in glomerulus increases capillary SA available for filtration
INCREASE GFR
Neural Regulation
(GFR)
Constriction of afferent arterioles through activation of receptors and increased release of renin
DECREASE GFR
What causes the release of Norepinephrine?
Increase in activity level of renal sympathetic nerves releases norephinephrine
What are the two types of Renal Autoregulation?
(GFR)
Myogenic Mechanism
Tubuloglomerular feedback
What triggers Tubuloglomerular Feedback?
(GFR)
Rapid delivery of Na+ and Cl- to the macula densa due to high systemic blood pressure
What triggers the Myogenic Mechanism?
(GFR)
Increases stretching of smooth muscle fibres in afferent arteriole walls due to increased BP
Myogenic Mechanism (GFR)
Stretched smooth muscle fibres contract, therby narrowing lumen of afferent arterioles
DECREASE GFR
Tubuloglomerular Feedback (GFR)
Decreased release of nitric oxide (NO) by juxtaglomerular apparatus causes constriction of afferent arterioles
DECREASE GFR
Why is urine output directly proportional to renal pressure?
Higher the pressure, higher the urine output
(doesn’t affect the filtration rate)
