Flashcards
BMS10-1027 (Control of Vasculature and Blood Pressure)
Cards in this deck (33)
- 1What is the difference between SNS and PNS effects on Vascular tone?1. PNS causes selective vasodilation (salivary glands, pancreas, sex organs, intestine) and doesn't impact TPR
2. SNS redistributes blood and can affect TPR - 2What is the difference between adrenaline and noradrenaline?Noradrenaline maintains myogenic tone and is released constantly
Adrenaline is released by the adrenal medulla mainly, and is only during fight/flight. It uniquely binds to B2 - 3What occurs when noradernaline binds to B1/A1 receptors?B1: Increase HR/cardiac contractility
A1: Vasoconstriction of most vascular beds - 4What occurs when adrenaline binds to B1/A1/B2 receptors?B1: Increase HR/cardiac contractility
A1: Vasoconstriction of most vascular beds
B2: VASODILATION of heart/liver/skeletal muscle arterioles - 5What do the following hormones cause? 1. Angiotensin II 2. Vasopressin (ADH) 3. Atrial Natriuretic1. Vasoconstriction
2. Vasoconstriction, an increase in blood volume
3. Vasodilation - 6What signal does the PNS send and what does it do?ACh, binds muscarinic receptors on pacemaker to lower HR
- 7What signal does the SNS send and what does it do?Noradernaline, binds to:
1. B1 receptors on pacemaker (increase HR)
2. B1 receptors on myocardium (increase contractile force) - 8What does vascular tone determine?1. BP, TPR, CO
2. Distribution of blood - 9How does myogenic autoregulation contribute to vascular tone?Arterioles respond to increase in pressure by increasing contraction
Protects glomerulus from too high pressure - 10How do Prostanoids (prostaglandins and thromboxanes) affect vascular tone?Vasoconstrictors: TXA2, PGF2
Vasodilators: PGE, PGI - 11How does Bradykinin affect vascular tone?1. Vasodilation through production of nitric oxide
2. Increase vascular permeability - 12How does histamine affect vascular tone?Mast cells release to:
1. Vasodilation (nitric oxide)
2. Increase vascular permeability - 13How does nitric acid affect vascular tone?1. Endothelial nitric oxide synthase in endothelial cells make NO, diffuse to smooth muscle
2. Leads to calcium storage in sarcoplasmic reticulum/no cGMP = no contraction
3. So vasodilation - 14What is endothelial nitric oxide synthase in endothelial cells stimulated by?Laminar flow, Ca2+
- 15What are the 5 determinants of BP?1. Stroke Volume
2. Heart Rate
3. Total peripheral resistance
4. Central venous pressure
5. Blood volume - 16Where are the mechanoreceptors for the baroreceptor reflex located?Aortic arch and carotid sinus
- 17What does increased BP lead to?Increased firing of baroreceptors
- 18What are the effects of increased baroreceptor firing?Increases PNS activity (release ACh to pacemaker cells)
Decreases SNS activity on cardiac myocates (fall in HR, CO, Contractile force, TPR etc, vasodilation of vessels)
Lowered BP - 19What nerves do signals from the mechanoreceptors travel to the brain with?1. Vagus nerve
2. Glossopharyngeal nerve - 20How does blood volume regulate blood pressure in the Short vs. long term?Short: raise in BV=raise in BP
Long: raise in BV=excretion of excess fluid/salt=fall in BV/BP - 21What determines blood volume?Plasma osmolarity
- 22How does increased osmolarity impact blood volume?Raise in thirst/ADH/water reabsorption
Increase in BV - 23What does metabolic hyperaemia occur in response to? What happens? What is the main factor contributing to this?Excercise
Vasodilation
Increase in metabolism+vasodilation allows muscles to get more nutrients etc.
Local factors are the main factor causing increased blood flow - 24What does reactive hyperaemia occur in response to? What happens?Blood flow cut off
Metabolites accumulate and trigger vasodilation until washed out - 25How is thermoregulation achieved by the arteriovenous anatomoses?Cold: Vasoconstriction
Hot: Decrease in sympathetic, vasodilation, more blood to surface (dermal venus plexus), more heat loss - 26What does the skeletal muscle pump do?Aids venous return in legs
- 27Since diastolic pressure is the lowest pressure point in the cardiac cycle, how is BP maintained?Energy stored in the elastic walls during systole released to mantain
- 28What does renin do?Converts angiotensin to angiotensin II
- 29What does angiotensin II do?1. Vasoconstrictor
2. Stimulates ADH release, which increases H20 reabsorption
3. Stimulates release of aldosterone from adrenal gland to increase Na+ reabsorption
Increased BV as result - 30What does a raise in BV lead to?1. Increased BV-->increased central venous pressure detected by mechanoreceptors
2. Vasodilation of afferent arterioles in glomerulus caused by Atrial Natrutiec Peptid-->increased GFR/water excretion
3. Lowered renin/Angiontensin II/ADH
4. As result, diuretics (more urine) and natriuresis (Na+ excretion)-->Lowered BV - 31What does pressure natriuresis occur in response to? What happens?1. Increased BV
2. local metabolite release in renal artery leads to vasodilation, increased natriuresis
3. Leads to fall in BV/BP - 32What is syncope? What is it caused by?1. Fainting due to blood/needles
2. Due to increase in PNS (lowered HR/Vasodilation) and lowered SNS (lowered CO/TPR=fall in BP+lowered blood flow to brain) - 33What are 3 functional adaptations of the pulmonary circulation?1) Low pressure
2) Unaffected by ANS, no metabolic regulation
3) Hypoxic pulmonary vascoconstriction
- High CO2 will usually cause vasodilation but here it causes vasoconstriction to reduce blood to unoxygenated areas
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- Description
- Describe extrinsic (e.g. ANS, hormones) and intrinsic influences (myogenic, autoregulation, metabolites) on vascular tone Outline how vascular control differs in different circulations Outline factors that influence systolic, diastolic and mean blood pressure Describe the acute control of blood pressure and the baroreceptor reflex Describe the long term control of blood pressure and the influence of blood volume Describe the mechanisms leading to syncope (vasovagal attack)
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- Evian Chai
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