Topic 5 Blood Pressure 2024 PDF

Topic 5 Blood Pressure 2024  Topic 5 Objectives Explain the underlying rationale which allows for the indirect measurement of blood pressure using a BP Cuff. Relate systolic pressure, diastolic pressure, mean arterial pressure and pulse pressure in an equation. Differentiate between...

Topic 5 Blood Pressure 2024  Topic 5 Objectives Explain the underlying rationale which allows for the indirect measurement of blood pressure using a BP Cuff. Relate systolic pressure, diastolic pressure, mean arterial pressure and pulse pressure in an equation. Differentiate between carotid sinus and aortic baroreceptors in terms of anatomical location and afferent nervous connections. Describe the sequence of events to restore blood pressure which coincide with an acute rise or fall in arterial pressure. TBA  Topic 5 Mini Case Sun Wen is a 20 year old Human Kinetics student and an aspiring UBC varsity track Athlete As she wakes up she measures her HR, it’s 45 bts/min She arrives at the Bird Coop at 6am for her usual pre-class work out She starts her routine of light stretching and can feel her heart rate slowly begin to rise (~80 bts/min). She gets on the stair master and begins a moderate intensity workout Her HR rises and stabilizes at 145 bts/min. [Her blood pressure stays roughly the same]  Blood Pressure What is it? – Pressure inside blood vessels or heart chambers relative to atmospheric. (Units: mmHg)  How does your brain know what your blood pressure is and what does it do about it??? Medulla Brain Efferent Afferent Nerves nerves Blood Pressure Blood Pressure (controller) (sensor) Baroreceptors Sympathetic NS Parasympathetic NS What are Baroreceptors? stretch-sensitive nerve endings Where are they? Carotid Sinus: In common carotid a. Afferent nerve: Glossopharyngeal n. Aortic Arch: In arch of the aorta Afferent nerve: Vagus n.  Brain  SVR - + SNS SV Baroreceptors PSNS If BP rises acutely:  HR ↑ stretch of baroreceptors ↑ firing of afferent nerves ↓ Heart Rate ↑ stimulation of PSNS ↓ Stroke Volume ↑ inhibition of SNS ↓ SVR & since BP = HR X SV X SVR therefore… Restores Blood Pressure to normal  Brain - ↑ SVR + SNS Baroreceptors PSNS ↑SV ↑ HR If BP falls acutely: ↓ stretch of baroreceptors ↓ firing of afferent nerves ↑ Heart Rate ↓ stimulation of PSNS ↑ Stroke Volume ↓ inhibition of SNS ↑ SVR & since BP = HR X SV X SVR therefore… Restores Blood Pressure to normal What about hormones ? Brain - - AVP SNS + Baroreceptors + SVR KIDNEY Renin – AII Na+ reabsorption Aldosterone BV Water reabsorption  If blood pressure goes up Brain - - AVP SNS + Baroreceptors + SVR BV leads to CO SVR leads to BP KIDNEY Renin – AII Na+ reabsorption Aldosterone BV Water reabsorption  If blood pressure goes down Brain - - AVP SNS + Baroreceptors + SVR BV leads to CO SVR leads to BP KIDNEY Renin – AII Na+ reabsorption Aldosterone BV Water reabsorption Nice to know… Hypertension – high blood pressure Blood Pressure Systolic Diastolic Category mm Hg (upper #) mm Hg (lower #) Normal less than 120 less than 80 and Prehypertension 120 – 139 80 – 89 or High Blood Pressure 140 – 159 90 – 99 (Hypertension) Stage 1 or High Blood Pressure 160 or higher or 100 or higher (Hypertension) Stage 2 Hypertensive Crisis Higher than 180 or (Emergency care needed) Higher than 110 Nice to know… Hypertension – high blood pressure Medications Beta blockers – reduce heart rate, CO and BP Thiazide diuretics – reduce blood volume in vessels and BP Angiotensin Converting Enzyme (ACE) inhibitors – prevent the formation of Angiotensin II Nice to know… Hypertension – high blood pressure Eat well, reduce salt Maintain a healthy weight Manage stress Avoid tobacco Comply with medical prescriptions Limit alchohol Understand hot tub safety Enjoy regular physical activity  Topic 5 Mini Case Sun Wen is a 20 year old Human Kinetics student and an aspiring UBC varsity track athlete. Her alarm goes off at 5:30am As she wakes up she measures her HR, it’s ~ 49 bts/min She arrives at the Bird Coop at 6am for her usual pre-class work out She starts her routine of light stretching and can feel her heart rate slowly begin to rise (~80 bts/min). She gets on the stair master and begins a moderate intensity workout. Her HR rises and stabilizes at 145 bts/min. Why is Sun Wen’s HR so low when she wakes up? Phenomenon called “training-induced” OR “athletic” bradycardia. Mechanisms: – Increased vagal tone, reduced SA node pacemaker activity** – Passive, due to increased SV with no change in CO – Beta receptor desensitization or other “intrinsic” mechanisms (controversial) Max HR for females is 226-Age (for males: 220- Age) Summary: Cardiovascular adaptations to exercise ↑ Left ventricle size and wall thickness (hypertrophy) ↑ Stroke Volume (volume effect) ↓Resting and submaximal HR ↑ Blood Volume Blood Pressure does not change or slightly ↓ Cardiac Output better distributed to active muscles  Comparison of CV Responses to Incremental Exercise Before and After Training Trained Untrained 180 220 HR (beatsmin-1) SV (mL·beat-1) 180 120 140 100 60 60 40 0 0 0 2 4 6 8 10 12 0 2 4 6 8 10 12 Time (min) Time (min) Adapted from: Plowman SA, Smith DL. Exercise Physiology for Health, Fitness and Performance. 2nd ed: Benjamin Cummings; 2003.  Last Case Objective With respect to Sun Wen, the UBC varsity athlete, describe her cardiovascular status at rest and how it changes during her adaptation to exercise. Office hours - Zoom Wednesday December 11th 10 am