hypertension Flashcards
what are the 2 types of hypertension?
pulmonary hypertension
systemic hypertension
pulmonary hypertension?
- increased blood pressure in the arteries of the lungs
- right side of the heart has to work harder
- rare
- more common in patients with another heart or lung condition
- usually only diagnosed if severe and symptomatic
causes of pulmonary hypertension?
- can be due to hypoxia
- endothelial dysfunction
- genetics
- blockage/damage to blood vessels
- side effects of drugs
- left sided HF
systemic arterial hypertension?
- systemic arterial hypertension is the condition of persistent non-physiological elevation of system blood pressure
value definition for systemic arterial hypertension?
systolic >140 mmHg (and/or)
diastolic > 90 mmHg
how is systemic arterial hypertension identified as one of the major casual risk factors for cardiovascular disease?
because it is a silent killer that can cause:
- heart attack
- kidney failure
- vision loss
- stroke/dimmentia
hypertension risk factors?
- genetic
- environmental
- age
- weight
- sex:
< 60 years more prevalent in males
>60 years more prevalent in females - race:
african Americans are more effected due to RAAS - education status
- diet
what 2 monitor tests should be done to confirm HT?
- ambulatory blood pressure monitoring (ABPM)
- home blood pressure monitoring (HBPM)
ambulatory blood pressure monitoring?
- measured twice per hour during waking hours
- at least 14 measurements to calculate an average
home blood pressure monitoring?
- monitored twice daily (day/night, sitting)
- 2 recordings, 1 min apart for 7 days (at least 4)
- all recordings after 1st to calculate an average
who should have their BP measured for HT?
how many readings should be done?
- all adults >40 years
- < 40 years with a family history of atherosclerosis
- minimum of 3-4 pairs of readings gathered over 3-4 months
3 classes of hypertension?
- stage 1 hypertension
- stage 2 hypertension
- severe hypertension
stage 1 hypertension
- clinical BP is 140/90 mmHg or higher
- ambulatory or home blood pressure monitoring daytime average is 135/85 mmHg (take 5 off both respectively)
stage 2 hypertension
- clinical BP is 160/100 mmHg or higher
- ABPM or HBPM daytime average is 150/95 mmHg or higher (take 10 off respectively)
severe hypertension
- clinical systolic BP is 180 mmHg or higher
- clinical diastolic BP is 110 mmHg or higher
primary hypertension (systemic arterial hypertension)
- “essential” or “idiopathic” hypertension
- accounts for around 95% of human hypertension
cause of primary hypertension?
- no apparent underling cause
- weight
- lifestyle
- diet:
sodium intake, lack of excersise, alcohol, smoking - genetics
- organ systems (heart, brain, kidney, vasculature= most effected)
short term control of BP?
BP= CO x TPR
CO= stroke volume x HR
- complex interactions of neurohormonal and local control systems that regulate BP and local tissue flow.
- but it also involves additional system that regulate circulatory volume in relation to vascular capacitance (long term control)
long term control of BP?
effective circulating volume (ECV)
(kidneys)
what are the 3 possible contributions to systemic hypertension?
1- increased sympathetic activity/sensitivity
2- renin angiotensin aldosterone system (RAAS)
3- Circulating factors
what interactions does SNS have to control BP?
- blood vessel tone
- heart rate and force of contraction
- adrenal gland secretion of adrenaline
how do SNS and PSNS work to control visceral activity?
synergistically (often opposite)
describe the sympathetic pathway for norepinephrine release?
preganglionic fibre (from CNS) synapses on a ganglion in the periphery
- releasing Ach onto an N2 receptor
- releasing norepinephrine
- binding to alpha and beta adrenoreceptors
describe the sympathetic pathway for epinephrine release?
preganglionic fibre (from CNS) synapses on a ganglion in the periphery
- releasing Ach onto an N2 receptor
- releasing adrenaline
- binding to alpha and beta adrenoreceptors
where is adrenaline released from?
chromaffin cells not a post ganglionic neurone
describe the parasympathetic pathway of neurotransmission?
pregandlionc fibres release Ach
- binds to N2 receptor
- postganglionic fibres release Ach
- this acts on M muscarinic receptors
what effect will binding of noradrenaline have on a1 receptors?
vasoconstriction in vascular smooth muscle
what are the alpha and beta receptors bound too?
g coupled receptors
- signalling cascade will happen inside
what is the intracellular action of a specific catecholamine determined by?
the complement of receptors expressed on the cell surface
what is isoprenaline?
synthetic B agonist
(pulmonary hypertension)
What does it cause the heart to do?
When it is more common?
When is it usually diagnosed?
- Pulmonary hypertension causes the right side of the heart to work harder
- PH is More common in patients with another heart or lung condition
- It is usually only diagnosed when severe and symptomatic
What is the diagnosis and treatment for clinic BP and ABMP and HPBM:
* Stage 1 hypertension
* Stage 2 hypertension
* Severe hypertension
What is the diagnosis and treatment for clinic BP and ABMP and HPBM:
* Stage 1 hypertension
* Stage 2 hypertension
* Severe hypertension
What is the formula for blood pressure?
What is the formula for cardiac output?
What regulates BP and local tissue flow?
- Blood pressure = Cardiac output x Total peripheral resistance (MABP = CO x TPR)
- Cardiac output (CO) = Stroke volume (SV) x Heart rate (CO – SV x HR)
- BP and local tissue flow is regulated by complex interactions of neurohormonal and local control systems
- Additional systems that regulate blood volume in relation also regulate blood pressure
What are the Sympathetic and Parasympathetic nervous systems?
What 3 factors can the SNS control that affect blood pressure?
- The Sympathetic and Parasympathetic nervous system are two major efferent pathways controlling targets other than skeletal muscle
- 3 factors the SNS controls that affect blood pressure:
1) Blood vessel tone (responsible for vasoconstriction – increased blood pressure)
2) Heart rate and contractility (increases both – positive chronotropic and inotropic effects – increased blood pressure)
3) Adrenal gland secretion of adrenaline (increases stroke volume and heart rate, hence increasing cardiac output (CO = SV x HR)
What are catecholamines?
What are 3 examples of catecholamines?
What do catecholamines do?
Describe 2 ways the sympathetic nervous system connects to effectors (4 steps each)
- Catecholamines are neurotransmitters in the central and peripheral nervous systems as well as hormones in the endocrine system
- Catecholamine examples:
1) Noradrenaline (Norepinephrine)
2) Adrenaline (epinephrine)
3) Isoprenaline (synthetic β-agonist) - Catecholamines bind adrenoceptors (adrenergic receptors) to elicit their actions
- How the sympathetic nervous system connects to effectors:
- Method 1:
1) Short pre-ganglionic fibre releases acetylcholine (Ach) in sympathetic ganglion
2) This Ach binds to nicotinic Ach receptors on the post-ganglionic neuron
3) This long post-ganglionic neuron goes out towards effectors and releases the catecholamine Norepinephrine
4) Norepinephrine binds to α and β adrenergic receptors on effectors, which can be smooth muscle, cardiac muscle, or glands - Method 2:
1) Short pre-ganglionic fibre releases acetylcholine (Ach) towards a chromaffin cell in the adrenal gland
2) The Ach binds to nicotinic acetylcholine receptors in the chromaffin cell (adrenal glands acts as a ganglion for syanpse)
3) This stimulates the release of adrenaline (epinephrine) into the vessels
4) The adrenaline can travel to effectors, where it binds to α and β adrenergic receptors on effectors
What are catecholamines?
What are 3 examples of catecholamines?
What do catecholamines do?
What are the 4 different types of adrenoreceptor?
How do catecholamine interaction with adrenergic receptors (adrenoreceptors) differ?
How is the intracellular action of a specific catecholamine determined?
- Catecholamines are neurotransmitters in the central and peripheral nervous systems as well as hormones in the endocrine system
- Catecholamine examples:
1) Noradrenaline (Norepinephrine)
2) Adrenaline (epinephrine)
3) Isoprenaline (synthetic β-agonist) - Catecholamines bind adrenoceptors to elicit their actions
- The 4 different types of adrenoreceptor are:
1) α1
2) α2
3) β1
4) β2 - Each catecholamine demonstrates different affinities to each receptor
- Intracellular action of a specific catecholamine is determined by the complement of receptors expressed on the cell surface (GPCR)
Describe the effects of Adrenaline, Noradrenaline, and Isoprenaline on α1 and α2 receptor tissues.
What are these 2 receptor tissues?
Which catecholamine has the highest affinity for each receptor?
What effect does affinity have on the effect of the catecholamine on the effectors?
- Effects of Adrenaline, Noradrenaline, and Isoprenaline on α1 and α2 receptor tissues
- Which catecholamine has the highest affinity for each receptor
- The greater the affinity of a catecholamine for a receptor on an effector, the lesser the concentration of catecholamine required to achieve maximal effect on the effector
Describe the effects of Adrenaline, Noradrenaline, and Isoprenaline on β1 and β2 receptor tissues.
What are these 3 receptor tissues?
Which catecholamine has a higher affinity for each receptor?
- The effects of Adrenaline, Noradrenaline, and Isoprenaline on β1 and β2 receptor tissues.
- Which catecholamine has the highest affinity for each receptor
Describe the 4 pathways of sympathetic contribution to hypertension
- 4 pathways of sympathetic contribution to hypertension:
1) Increased signalling to vascular smooth muscle cells of blood vessels
* Norepinephrine acts on α1 receptors
* Increases vasoconstriction, which increases TPR, which increase BP
2) Increased signalling to pacemaker and contractile cells in heart
* Norepinephrine acts on β1 receptors
* Increases HR and contractility, which increases CO, which increases BP
3) Adrenal gland secretion of adrenaline
* Feeds into the first 2 pathways and has the same effects
4) Renin release
* Renin is released from juxtaglomerular cells of the kidneys in response to the circulating catecholamines that activate β1 adrenoreceptor on the kidneys
* This triggers RAAS pathway, which generates Angiotensin 2
* Angiotensin 2 acts as an AT1 and AT2 receptor agonist
- Roles of angiotensin 2:
1) Vasoconstriction
* Angiotensin causes vasoconstriction of renal arteries, which increases total peripheral resistance and constricts blood flow via the kidneys
2) Release of aldosterone
* Angiotensin 2 causes the release of aldosterone from the zona glomerulosa (outermost region) of the adrenal glands, which changes the volume of water excreted from the kidney by increasing Na+ and water reabsorption
3) Stimulation of release of ADH (anti-diuretic hormone / vasopressin) from the pituitary
* ADH increases blood volume by increasing water permeability in the renal collecting ducts, which decreases urine production
- All of these roles of angiotensin 2 lead to an increase in blood pressure
What is the nephron?
What is the function of the nephron?
What is Na+ in the blood?
What is the role of Na+ in the kidney?
What must the kidneys balance in relation to water and Na+?
Why is this done?
What is this system a target for?
- The nephron is the functional unit of the kidney
- The nephron filters blood (180L/day) and produces urine
- Na+ is the predominant cation in the ECF (Blood compromises 36% of ECF volume – ECF is sum of plasma volume and interstitial fluid volume)
- Movements of Na+ established osmotic gradients for H2O movement - In the kidneys, wherever the sodium moves, the water will follow
- Na+ is freely filtered across the glomeruli of the nephron, with 99% being reabsorbed through the long tubule of the nephron back into the blood
- The kidneys must balance Na+ and water intake with Na+ and water excretion
- This is done to maintain blood volume that makes up ECF volume, and therefore long-term BP
- This system is a critical target for anti-hypertensives
The RAAS system.
Describe the pathway in which decreased arterial pressure produces angiotensin 2
What vessels and receptors does angiotensin 2 act on?
What are 3 roles of angiotensin 2?
What do all of these roles lead to?
What is the purpose of the RAAS system?
- This full system is the RAAS system
- The pathway in which decreased arterial pressure produces angiotensin 2
1) Decreased arterial blood pressure
2) Leads to renin (enzyme) release from the juxtaglomerular cells of the kidneys
3) Renin substrate angiotensinogen is released from the liver
4) Venous blood from the liver and kidneys are mixes together
5) Renin breaks down angiotensinogen into angiotensin 1
6) This venous blood then circulates to the heart and then the lungs
7) Converting enzyme in the lungs converts angiotensin 1 to angiotensin 2 (active for short period of time)
8) Angiotensin rich blood then comes around the circulation - Angiotensin acts on resistance vessels
- Angiotensin 2 acts as an AT1 and AT2 receptor agonist
- Role of angiotensin 2:
1) Vasoconstriction
* Angiotensin causes vasoconstriction of renal arteries, which increases total peripheral resistance and constricts blood flow via the kidneys
2) Release of aldosterone
* Angiotensin 2 causes the release of aldosterone from the zona glomerulosa (outermost region) of the adrenal glands, which changes the volume of water excreted from the kidney by increasing Na+ and water reabsorption
3) Stimulation of release of ADH (vasopressin) form the pituitary
* ADH increases blood volume by increasing water permeability in the renal collecting ducts, which decreases urine production
- All of these roles of angiotensin 2 lead to an increase in blood pressure
- The role of the RAAS system is to increase MABP
Consequences of mild, moderate, and severe hypertension on the heart and blood vessels
Consequences of mild, moderate, and severe hypertension on the heart and blood vessels
