CVPR Week 7: Hemodynamics Flashcards
Objectives

Question 1

D. Angiotensin
Question 2

A. β adrenergic receptors
Question 3

I think it is B but not 100%
Identify


Identify


Identify


Determinants of renal blood flow

Renal blood flow % of CO
20%
Pressure in renal arteries

Renal capillaries properties
- Highly fenestrated capillaries have a high degree of permeability
- Two distinctly different capillary beds arranged in series
Distinct capillary beds of the renal system
- Glomerular capillaries
- Peritubular capillaries
Glomerular capillaries function
Filtration
PEritubular capillaries function
Reabsorption
Juxtoglomerular cells location
- Afferent arteriole
- abut closely to the distal tubule
Identify


Juxtaglomerular cells structure
Modified smooth muscle cells
Juxtaglomerular cells function
Produce and secrete renin
Identify


Identify


Vasa Recta Capillaries function
- Supply medullary blood flow
- maintain concentration gradient in the renal medulla
- Delivers nutrients
Vasa Recta Capillaries location
Form long loops paralleling loops of Henle
Identify

Vasa Recta Capillaries

Vasa Recta Capillaries % of renal blood flow
10% of renal blood flow
Control mechanisms of renal blood flow
2 listed
- Intrarenal (Autoregulation)
- Extrarenal (extrinsic regulation)
Intrarenal regulation AKA
Autoregulation
Autoregulation of renal blood flow AKA
Intrarenal
Autoregulation of renal blood flow mechanisms and effects
- Myogenic tone
- Tubuloglomerular feedback
Maintain constant RBF & GFR almost constant when arterial pressure changes
Extrinsic regulation of renal blood flow AKA
Extrarenal
Extrarenal regulation of renal blood flow AKA
Extrinsic regulation
Extrinsic regulation of renal blood flow mediators & effects
- Sympathetic nerves
- Renin-angiotensin system
- Other hormone regulators
Regulate renal function to maintain whole body fluid homeostasis
Renal autoregulation

Myogenic tone

Myogenic tone is affected by?
- Myogenic tone is independent of extrarenal forces
- Stretch stimulates VSMC contraction
Identify


Identify


Identify


Role of the sympathetic nerves in renal extrinsic regulation

Vascular smooth muscle cells sympathetic receptors for renal vasculature
α adrenergic receptors
Identify


Juxtaglomerular cells sympathetic receptors
Juxtaglomerularcells contain β1 adrenergic receptors
sympathetic effects on juxtaglomerular cells
Stimulate renin release
Leads to formation of angiotensin II
Identify


Identify


Hypoxia activation of SNSA does what?
Affects renal function

Organ systems affected by SNSA
- Kidneys
- Vascular smooth muscle
- Endocrine
Kidney effects of SNSA
- Constricts afferent and efferent arterioles t decrease renal blood flow
- Potently increases Na+ reabsorption in the proximal tubule
- Large activation decreases GFR
Vascular smooth muscle effects on SNSA
- Constricts arteries to decrease renal blood flow
Endocrine effects of SNSA
Stimulates renin secretion (β1 receptors) to increase levels of angiotensin II and vasopressin
Describe the Renin-Angiotensin System

Effects of activating the Renin-Angiotensin system
5 listed
- Thrist
- Vasoconstriction
- Water reabsorption
- Sodium reabsorption
results in increased extracellular fluid volume
Summary of the Renin-Angiotensin system

Describe the juxtaglomerular apparatus

Mediators of the RAS
- SNSA
- Aldosterone
- ADH
SNSA AKA
Sympathetic nervous system activation
RAS AKA
Renin-Angiotensin System
Aldosterone effects on RAS
Aldosterone increases distal tubulue Na+ reabsorption
- Increases Na/K-ATPase activity in distal tubule basolateral membrane
- Increases lumiinal membrane Na+ and K+ permeability
ADH effects on the RAS
ADH causes water reabsorption
- Stimulates water reabsorption in the collecting duct
- Increases urea reabsorption in the collecting duct
Effects of Angiotensin on vascular smooth muscle
Causes constriction of arteries increasing peripheral resistance resulting in increased arterial blood pressure
Effects of Angiotensin on the central and peripheral nervous systems
Facilitate sympathetic transmission resulting in:
- constriction of arteries leading to increased peripheral resistance leading to increased arterial blood pressure
- increased cardiac output resulting in increased arterial blood pressure
Effects of Angiotensin on Adrenal cortex
increased aldosterone secretion leading to increased sodium reabsorption leading to increased sodium & water reabsorption leading to increased cardiac output resulting in increased arterial blood pressure
Effects of Angiotensin on direct effects on the kidneys on the tubules and arterioles
- increased sodium reabsorption and decreased GFR leading to sodium and water retention leading to increased cardiac output resulting in increased arterial blood pressure
Effects of Angiotensin on the brain
Causes increased thirst leading to increased water reabsorption and Increased ADH leading to increased water reabsorption causing sodium and water retention causing increased cardiac output resulting in increased arterial blood pressure
Angiotensin II effects on vascular smooth muscle

Angiotensin II effects on central and peripheral nervous systems

Angiotensin II effects on adrenal cortex

Angiotensin II effects on renal tubules and arterioles
Angiotensin II effects on the brain

Prostaglandins effect on renal blood flow
- Typically do not regulate renal blood flow or GFR under normal conditions (i.e. cyclo-oxygenase inhibition does not alter renal blood flow)
- Vasodilator PG’s limit constriction of afferent arteriole
- PG-induced vasodilation maintains glomerular blood flow during volume or sodium depletion
- Cyclo-oxygenase inhibitors can cause acute renal failure during dehydration or following a stress such as surgery
Cyclo-oxygenase inhibitors and renal function
Acute renal failure during dehydration or following a stress such as surgery
Atrial natriuretic peptide is secreted from?
atria in response to stretch
Atrial natriuretic peptide effects on GFR
Dilates afferent arteriole and also constricts efferent arteriole to increase GFR
Atrial natriuretic peptide effects on urine production
Decreases Na reabsorption in medullary collecting to cause diuresis and natriuresis
Diuresis description
increased urine production
Natriuresis description
excretion of sodium in the urine
Brain natriuretic peptide secreted from
ventricles
Atrial natriuretic peptide and Brain natriuretic peptide levels in renal failure
increased levels in renal failure
ANP and BNP effects in renal failure
Increased levels in renal failure resulting in
- reduced renal clearance
- increased synthesis