Lecture 6 Flashcards
What is renovascular hypotension?
restriction of renal bloodflow
What percentage of the cardiac output goes to the kidneys?
20% (kidneys are only 0.5% of body weight)
Important thing to know about kidneys
Kidneys are an important component of TPR.
What is the relationship between Cardiac output that an organ receives and TPR?
Whatever demand an organ has on cardiac output it contributes to the TPR when blocked.
What kind of disease is Autosomal dominant polycystic disease? What is the incidence of this condition?
One of the most common genetic diseases affecting 1 in 700 people. It is an autosomally dominant condition and 10% of affected individuals have no family history of the condition (false paternity or de novo mutation).
What happens during autosomal dominant polycystic kidney disease?
Cysts develop in various organs. In kidneys the chance of it developing is 100%. This causes an increase in blood pressure due to the occlusion of arteries.
People with this condition present with early hypertension and often cause renal failure.
cysts appear in about 1% of nephrons. Many nephrons exist meaning a lot of cysts form.
How does the cyst grow in ADPKD?
Thin wall of nephron grows out and fill with fluid and then loses continuity with the nephron.
Obstruction of nephron flow doesn’t prevent growth of cyst. Cells proliferate considerable.
What loci get the mutation during ADPKD?
PKD1 (chromosome 16) in 85% of cases with more than 64 mutations. Normally encodes polycystin - 1.
PKD2 (chromosome 4) encodes polycystin - 2 responsible for 15% of cases caused by more than 50 different mutations.
What is the result of a polycystin mutations?
Polycystin mutation causes disruption of basement membrane of nephrons and as a result ion channels are influenced.
How does the kidney regulate GFR?
By constriction afferent arteriole of the kidney.
What is the function of the juxtaglomerular apparatus?
Senses blood pressure going into the apparatus to regulate blood flow to kidney.
What are the components of the juxtaglomerular apparatus?
Macula densa cells (baroreceptors)
Juxtaglomerular cells which produce renin
Extraglomerular mesangial cells
What is the hormone released by the juxtaglomerular apparatus?
Renin
How does ADPKD affect blood pressure?
Blood pressure in preglomerular arteriole of polycystic condition is higher due to increase in renin production by the juxtaglomerular apparatus.
Renin levels are doubled in patients with ADPKD
Despite this the renal plasma flow is a lot lower.
What is the effect of ADPKD on hormone levels?
ADPKD increases plasma renin, aldosterone, and Atrial Natriuretic Peptides. This causes an increase in sodium retention and plasma volume causing increase in BP.
