CPRS 29 30: Blood Flow and Blood Pressure Flashcards
What is the formula for calculation of Mean Arterial Pressure
By stroke volume, heart rate, total peripheral resistance
Stroke volume x Heart Rate x Total Peripheral Resistance
Laplace equation: How to calculate tension?
Transmural pressure x (Vessel radius/vessel wall thickness)
Which section in the blood vessels have the highest resistance?
Arterioles
NOT capillaries
Name 3 assumptions in resistance calculation
- Vessel is ______ and _____ and has constant _____
- Blood flow is ________ and _______
- Blood has constant _________
Name 3 assumptions in resistance calculation
- Vessel is straight, cylindrical and have constant radius
- Blood flow is laminar and steady
- Blood has constant viscosity
Why does veins have higher compliance (lower elasticity) than arteries?
Because arteries have thicker ___________ making it more difficult to change shape
After aging of arteries, the arterial wall gets even thicker. The artery will be _______ elastic (less or more)
Why does veins have higher compliance (lower elasticity) than arteries?
Because arteries have thicker collagen fibres/ elastic fibres making it more difficult to change shape
After aging of arteries, the arterial wall gets even thicker. The artery will be more elastic (less or more)
Normal Arteries
- Systole: After blood ejection from the left ventricle, small portion of blood leaves the aorta immediately. Some remains in the aorta and stretch the aorta, which increases the aortic pressure.
-Diastole: After elastic recoil, there is minor backflow of blood that closes the _______ and most blood are pushed towards downstream
Rigid Arteries
- Systole: Volume of blood equal to the entire ________ will leave the aorta which increases the aortic pressure by a lot
- Diastole: Blood flow will _____________
Normal Arteries
- Systole: After blood ejection from the left ventricle, small portion of blood leaves the aorta immediately. Some remains in the aorta and stretch the aorta, which increases the aortic pressure.
-Diastole: After elastic recoil, there is minor backflow of blood that closes the aortic valve and most blood are pushed towards downstream
Rigid Arteries
- Systole: Volume of blood equal to the entire stroke volume will leave the aorta which increases the aortic pressure by a lot
- Diastole: Blood flow will cease
Name the systolic and diastolic pressure range for the following
Normal:
Prehypertension:
Hypertension Stage 1:
Hypertension Stage 2:
Name the systolic and diastolic pressure range for the following
Normal: <120; <80
Prehypertension: 120-139; 80-89
Hypertension Stage 1: 140-159; 90-99
Hypertension Stage 2: >160; >100
Name the vascular shunt when all the precapillary sphincters are closed/ fully contracted
Metarteriole
For the smooth muscles, what are the dense body made of?
Vimentin and Desmin
What are the details of process during the smooth muscle contraction process?
- Increase Ca2+ due to increase _________ and increased influx of Ca2+
- More Ca2+ binds to __________
- __________ binds and activates more ________
- More MLCK _______________
- Increase myosin heads binding to actin facilitating contraction
What are the details of process during the smooth muscle contraction process?
- Increase Ca2+ due to increase CICR and increased influx of Ca2+
- More Ca2+ binds to Calmodulin (CaM)
- Ca2+-CaM binds and activates more MLCK
- More MLCK phosphorylates more myosin
- Increase myosin heads binding to actin facilitating contraction
What are the details for the smooth muscle relaxation process?
- Decrease in Ca2+ due to __________ and _____________
- Decrease Ca binding to ________
- Decreased formation of __________ complex
- Decrease MLCK which___________
or
Phosphorylates _________ so it becomes less sensitive to be activated by _______________
What are the details for the smooth muscle relaxation process?
- Decrease in Ca2+ due to Ca2+ pumped in SR by SERCA and Ca2+ pumped out by Ca2+ ATPase
- Decrease Ca binding to Calmodulin (CaM)
- Decreased formation of Ca2+-CaM complex
- Decrease MLCK which phosphorylates less myosin
or
Phosphorylates MLCK so it becomes less sensitive to be activated by Ca2+-CaM
By T = Transmural pressure x (Radius/thickness of vessel)
When blood pressure increases, what will happen
When vessel radius reduces, what will happen
By T = Transmural pressure x (Radius/thickness of vessel)
When blood pressure increases, what will happen
The transmural pressure increases, tension increases
When vessel radius reduces, what will happen
Tension reduces
Consider Nitric Oxide - Endothelium derived vasoconstrictor/ vasodilator? - Agonists? - Mechanism of action: Activates \_\_\_\_\_\_\_\_ More \_\_\_\_\_\_ becomes \_\_\_\_\_\_ Increase activity of \_\_\_\_\_\_\_\_\_\_ Increase phosphorylation of \_\_\_\_\_\_\_\_\_ Increase \_\_\_\_\_\_ Ca2+ sequestration by SR Smooth muscle relaxation
Consider Nitric Oxide - Endothelium derived vasodilator - Agonists: Acetylcholine, Histamine - Mechanism of action: Activates guanylyl cyclase More cGTP becomes cGMP Increase activity of Protein Kinase G Increase phosphorylation of MLCK Increase SERCA Ca2+ sequestration by SR Smooth muscle relaxation
Consider Prostaglandin I2 - Endothelium derived vasoconstrictor/ vasodilator? - Mechanism of action: Activates \_\_\_\_\_\_\_\_ More \_\_\_\_\_\_ becomes \_\_\_\_\_\_ Increase activity of \_\_\_\_\_\_\_\_\_\_ Increase phosphorylation of \_\_\_\_\_\_\_\_\_ Increase \_\_\_\_\_\_ Ca2+ sequestration by SR Smooth muscle relaxation
Consider Prostaglandin I2 - Endothelium derived vasodilator? - Mechanism of action: Activates adenylyl cyclase More cATP becomes cAMP Increase activity of Protein Kinase A Increase phosphorylation of MLCK Increase SERCA Ca2+ sequestration by SR Smooth muscle relaxation
Consider Endothelin-1 - Endothelium derived vasoconstrictor/ vasodilator? - Mechanism of action: Activates \_\_\_\_\_\_\_\_ Increase \_\_\_\_\_\_ level in cytoplasm Increase \_\_\_\_\_\_ bind on \_\_\_\_\_\_ receptors in SR Increase Calcium release by SR Increase \_\_\_\_\_\_ activity Increase smooth muscle contraction
Consider Endothelin-1 - Endothelium derived vasoconstrictor? - Mechanism of action: Activates Phospholipase C (PLC) Increase IP3 level in cytoplasm Increase IP3 bind on IP3 receptors in SR Increase Calcium release by SR Increase MLCK activity Increase smooth muscle contraction
Classify the following as Vasodilator or Vasoconstrictor Angiotensin II Acetylcholine Epinephrine Norepinephrine
Classify the following as Vasodilator or Vasoconstrictor Angiotensin II- Vasoconstrictor Acetylcholine- Vasodilator Epinephrine- Vasodilator Norepinephrine- Vasoconstrictor
Compare unitary smooth muscle VS multiunit smooth muscle
- influence by neurons
- apply to which blood vessels?
- Gap junctions?
Compare unitary smooth muscle VS multiunit smooth muscle
- bunch of smooth muscle cells influenced by single neuron VS smooth muscle cells influenced individually by different neurons
- In most blood vessels VS In aorta or large elastic arteries
- Smooth muscle cells connected by gap junctions VS not connected by gap junctions
In splanchnic circulation (activated when a person thinks about food), the CNS will initiate a response to increase the splanchnic blood flow
In this circulation, what substance is required for vasoconstriction, what substance is required for vasodilation?
Constriction: NE
Dilatation: Adenosine
Coronary blood flow is higher during
systole or diastole?
diastole
During exercise, the circulation would be as follows:
- _____ binds to alpha receptors on VSMC to cause vasoconstriction of ______ muscles
- _______ is responsible for vasodilatation of arterioles in ______ muscles
- Will reduce ______ circulation so the blood flow is diverted more to skeletal muscles
During exercise, the circulation would be as follows:
- NE binds to alpha receptors on VSMC to cause vasoconstriction of inactive muscles
- Adenosine is responsible for vasodilatation of arterioles in active muscles
- Will reduce splanchnic circulation so the blood flow is diverted more to skeletal muscles
When there is increased arterial pressure, what is the response after detected by baroreceptors?
When there is increased arterial pressure, what is the response after detected by baroreceptors?
Decrease cardiac output
Decrease peripheral resistance
Finally: Decrease in mean arterial pressure
(P=COxTPR)
When there is decreased arterial pressure, it will stimulate chemoreceptors. What are the responses
Increase cardiac output
increase peripheral resistance
Finally: Increase in mean arterial pressure
(P=COxTPR)
When the initial heart rate is low, what type of reflex will be triggered?
When the initial heart rate is high, what type of reflex will be triggered?
When the initial heart rate is low, what type of reflex will be triggered? Bainbridge reflex, causing acceleration of heart rate
When the initial heart rate is high, what type of reflex will be triggered? Baroreceptor reflex, cause decrease in heart rate
When Tension is too high, the first step to reduce tension is called Inward Eutrophic Remodelling.
By Tension = Transmural pressure x (radius/thickness), deduce what will happen
But what will happen if it’s prolonged?
When Tension is too high, the first step to reduce tension is called Inward Eutrophic Remodelling.
By Tension = Transmural pressure x (radius/thickness), deduce what will happen next
Decrease radius (Vasoconstriction) Prolonged: Lead to increased resistance due to prolonged vasoconstriction
When Tension is too high, the first step to reduce tension is called Inward Eutrophic Remodelling.
The radius of vessel will reduce, in order to reduce the tension. What if it is still not enough to reduce the tension,
It will undergo hypertrophic remodelling. What is the principle behind it?
When Tension is too high, the first step to reduce tension is called Inward Eutrophic Remodelling.
The radius of vessel will reduce, in order to reduce the tension. What if it is still not enough to reduce the tension,
It will undergo hypertrophic remodelling. What is the principle behind it?
To increase the deposition of extracellular matrix proteins, like collagen or fibronectin, so that the vessel wall will thicken, which reduces the tension
By Tension = Transmural pressure x (radius/thickness), deduce what will happen