The cardio lab Flashcards
Contractile state of resistance arterioles (Neural)
- sympathetic & parasympathetic NS
Contractile state of resistance arterioles (Hormonal)
- Renin-angiotensin-aldosterone system (RAS)
Contractile state of resistance arterioles (Local Transmitters)
- Nitric Oxide (NO)
Antihypertensive Drug Strategies to Reduce cardiac output
- (beta-adrenergic blockers: not 1st line)
- Ca2+ channel blockers
Antihypertensive Drug Strategies to Dilate resistance vessels
- Ca2+ channel blockers
- Renin-angiotensin system blockers
- alpha-1 adrenoceptor blockers
- Nitrates
Antihypertensive Drug Strategies to Reduce vascular volume
- Diuretics. RAS blockers
ACE Inhibitors
- Perindopril
- Ramipril
- anything else ending in -pril
Angiotensin receptor blocker (ARB)
- Candesartan
- Irbesartan
- anything else ending in -sartan
Autonomic Nervous System regulates blood pressure by?
effects on both pump output and resistance in the circulation.
* Parasympathic involves beta-1 adrenoceptors and control heart rate and contractility
* Sympathetic involves alpha-1 adenoceptors and control peripheral vascular resistance.
Parasympathic involves what receptor and affects what involving blood pressure
beta-1 adrenoceptors and control heart rate and contractility at the heart.
Sympathetic involves what receptor and affects what involving blood pressure
alpha-1 adrenoceptors and control peripheral vascular resistance at the arteriole.
Beta-1 adrenoceptor antagonists
Metoprolol, atenolol, other –olol’s
Decrease blood pressure: Not 1st line: don’t lower stroke risk & mortality as well as other antihypertensive like propanol.
alpha-1 Adrenoceptor Blockers
Prazosin: Relaxes peripheral resistance vessels
Cardiac Muscle: Ca2+ storage in where?
sarcoplasmic reticulum
PVR meaning
Peripheral vascular resistence
Blood pressure is physiologically controlled by what
- cardiac output,
- peripheral vascular resistance, and
- blood volume.
The 4 major classes of antihypertensive drugs
- diuretics,
*β-blockers,
*calcium channel blockers, and
*renin-angiotensin system inhibitors
What is hypertension
High blood pressure
Cardiac output definition
The volume of blood flow from the heart through the ventricles and is usually measured in litres per minute (L/min).
Cardiac output equation
Stroke Volume x heart rate
Any factor that causes cardiac output to increase, by elevating heart rate and/or stroke volume, will elevate blood pressure and promote blood flow. Name some factors?
- sympathetic stimulation,
- adrenaline and noradrenaline, and
- increased calcium ion levels
The sympathetic nervous system innervates what increased cardiac output
- The sinoatrial node,
*the atrioventricular node, and
*both atrial and ventricular muscles via cervical, cervicothoracic, and thoracic nerves.
Factors that decreases cardiac output, by decreasing heart rate and/or stroke volume, will decrease arterial pressure and blood flow. This includes parasympathetic stimulation and decreased calcium levels. Para innervates:
- the sinoatrial node,
- the atrioventricular node, and
- the atrial muscles via the vagus nerve.
Peripheral vascular resistance definition
e refers to compliance, which is the ability of any compartment to expand to accommodate increased content.
The greater the compliance of an artery means?
The more effectively it can expand to accommodate surges in blood flow without increased resistance or blood pressure.
Compliance in the context of arteries
the ability of the arterial walls to stretch or expand in response to changes in blood pressure.
Decreased cardiac output involves what system
Parasympathetic
Increase cardiac output involves what system
Sympathetic
Which is more compliant veins or arteries?
Veins -> can expand and hold more blood
What happens to compliance when vascular disease causes stiffening of the arteries (e.g., atherosclerosis),
- compliance reduced
- resistance to blood flow in increased.
- results in more turbulence, higher pressure within the vessel, and reduced blood flow.
- This increases heart work
Blood volume definition
is the amount of blood moving through the body
What is the baroreceptor reflex?
a rapid and effective mechanism that responds to sudden changes in blood pressure regulation.
Baroreceptors are located where
In the carotid sinus in carotid arteries and aortic arch
Baroreceptors are sensitive to a change in what
Changes in the stretch or distension of arterial walls
What happen to arteries when blood pressure increases
Walls of artery stretch and activates baroreceptors to generate action potentials
Simple explain artery wall stretch and baroreceptors
Increase BP → Arterial wall stretch → Activate baroreceptors → Action potential → signal to vasomotor centre in brain
Simple pathway if BP is too high
The parasympathic NS activated → Acetylcholine released → ACh decreases heart rate → lower BP
Simple pathway is BP is too low
Stimulates Sympathetic NS → noradrenaline released → increase heart rate and contractile heart force → more vasoconstriction →increase in BP
How is BP regulated
Through the sympathetic and parasympathetic NS
Activation of the renin-angiotensin-aldosterone system (RAAS) is triggered by?
Low blood pressure, low blood volume, or low sodium levels in the bloodstream.
Simple pathway of renin to increase BP
↓ blood flow to the kidneys and/or ↑ sympathetic stimulation of kidneys
↓
Renin released from kidney
↓
Renin converts angiotensin precursor (angiotensinogen in liver) to inactive angiotensin I in circulation (lungs)
↓
angiotensin I is cleaved to active angiotensin II by angiotensin converting enzyme (ACE).
↓
Angiotensin II activates angiotensin II type 1 (AT1) receptors on blood vessels
↓
vasoconstriction and increased blood pressure
What does angiotensin II activate?
Angiotensin II activates AT1 receptors in the adrenal cortex →
releases aldosterone →
that stimulates mineralocorticoid receptors to increase reabsorption of sodium and water from kidneys →
this increases blood volume which also leads to elevated blood pressure.
Noradrenaline MoA
Alpha and beta adrenoceptor agonist
Adrenaline
Alpha and beta adrenoceptor agonist
Isoprenaline
Beta adrenoceptor agonist
Phenylephrine
Alpha 1 adrenoceptor agonist
Acetylcholine
Muscarinic and nicotinic receptor agonist
Propranolol
Beta - adrenoceptor antagonist
Prazosin
Alpha 1 adrenoceptor antagonist
Atropine
competitive muscarinic receptor antagonist
Verapamil
calcium channel blocker
