Week 2 Flashcards
What is the epidemiology of HTN?
- HTN is the leading risk factor for CVD mortality (13% of global deaths)
- Only about half % of people with HTN are compliant with medications
- Leading cause of CVD worldwide
- “Silent killer” often asymptomatic even at extremes
What kind of disabilities increases the chances of a patient getting HTN?
- Mobility limitation
- Cognitive limitation
- Vision limitation
- Hearing limitation
What are the fast mechanisms for the regulation of fast BP?
Baroreceptor located primarily in the Aortic Arch and Carotid Sinuses
What are the slow mechanisms for the regulation of fast B
• Renin-Angiotensin System (Kidneys)
• Natriuretic peptides (ANP in the atria and BNP in the ventricles) (Heart)
- Act as a counter to RAAS system. released from heart
How does the regulation of arterial blood flow work?
• Sympathetic neural activity: norepinephrine (norEph)
- Goal is to redistribute blood to areas of need, more global
- Arterioles are innervated by sympathetic, which release norEph
- norEph binds to alpha-1 receptors causing vasoconstriction
• Circulating epinephrine
• Circulating hormones: angiotensin II
• Local metabolites: prostaglandins
• Mechanical Factors: muscle contraction, vessel stretch (CA2+ influx)
What does circulating epinephrine bind to?
Beta 2 receptors located in arterial cells. Beta 2 receptors dilate blood vessels, bu they aren’t that many of them
What do local metabolites cause in working muscle?
They cause vasodilation to the working tissue which will allow us to deliver more blood flow, and oxygen and to get rid of waste
What is functional sympatholysis?
How our body regulates BP during exercise
What is functional sympatholysis tightly related to?
The endothelial function, if there is impaired endothelial tissues in the blood some of the function of the functional sympatholysis can be impaired
What is hemodynamics?
Blood flow parallels Cardiac Output
CO = HR X SV
How do you find CO?
Driving pressure divided by resistance to flow.
Or
(MAP-CVP) divided by total peripheral resistance (TPR)
What are the things that affects BP within blood vessels?
- Radius
- Viscosity (hematocrit)
- Length of vessel
- Resistance
Though our larger vessels can undergo larger changes in diameter, the bulk of the resistance in our bodies is in the _____
Though our larger vessels can undergo larger changes in diameter, the bulk of the resistance in our bodies is in the *micorvasculature (smaller vessels), which is why its so important to maintain normal endothelial function in that tissue
What is the role that the PT plays to reduce the risk of hypertension?
- Exercise
- Education
- Interdisciplinary communication
What is the mean arterial pressure for the regulation of BP using baroreflex/baroreceptors?
85 to 100mmHg in adults
What do baroreceptors respond to?
Stretching of the arterial wall
What are the characteristics of baroreceptors responding to stretching of arterial walls?
- Negative feedback loop with the Vagus and Glossopharyngeal nerves
- Arterial pressure suddenly rises, the walls of these vessels passively expand, increases the firing frequency of receptor action potentials.
- If arterial blood pressure suddenly falls, decreased stretch of the arterial walls leads to a decrease in receptor firing.
In the regulation of BP using baroreceptors, what pressures do carotid sinus receptors respond to?
Pressures ranging from 60-180 mmHg
What is the difference between aortic arch receptors and carotid sinus receptors in the regulation of BP with the use of baroreceptors?
Aortic arch receptors have a higher threshold pressure and are less sensitive than the carotid sinus receptors
What is renin?
An enzyme that is released into the circulation by the kidneys due to the detection of low blood flow through the arteries
What is the release of renin stimulated by?
• Sympathetic nerve activation (acting
through β1 -adrenoceptors)
• Renal artery hypotension (caused by systemic hypotension or renal artery
stenosis)
• Decreased sodium delivery to the distal tubules of the kidney
What is an essential hypertension?
Interaction between environmental factors and genetics. Accounts for 95-99% of cases
What is a secondary hypertension?
Result of some biochemical or mechanical pathology, potentially reversible
What are the contributors to HTN?
- Diet…Salt Sensitivity
- Inactivity
- Obesity
- Abnormalities of the adrenal cortex
- Sleep Apnea
- Sympathetic Nervous System Activity
- Kidney Disease
- Congenital Vascular Disorders
- Recreational Drugs and Alcohol