Handout packet 3 ( Exam 1)

Peripheral Cardiovascular adjustment- muscle blood flow ​

1. Muscle blood flow increases prior to exercise ​

2. Low intensity exercise leads to increased blood flow to oxidative muscle ​

3. High intensity exercise leads to increased blood flow to glycolytic muscle ​

4. Muscle blood flow can increase 100 fold ​

muscle blood flow _________ prior to exercise

Increases

Low intensity exercise leads to increased blood flow to

Oxidative muscles

high intensity exercise leads to increased blood flow to

Glycolytic muscles

Muscle blood flow can increase ___ fold

100

Functional sympatholysis

The body's natural process of reducing blood vessel constriction in active muscles during exercise to increase blood flow

A. Dilators act on SN to inhibit NE release​

B. Dilators make alpha receptors less responsive to NE​

C. Dilators act on vasculat smooth muscle to cause relaxation​

​

Vasodilators produced by endothelial cells

Nitric oxide, prostaglandins, Endothelium-derived hyperpolarizing factor​ (EDHF)

Vasodilators produced by skeletal muscle cells

K+, H+, CO2, Adenosine

Oxygen extraction (a-v O2 difference)​

O2 is used in ATP synthesis (note decreased venous o2​

Cardiovascular control during exercise

1. Signal originates in brain (central command)​

2. Signal originates in muscle (exercise pressor reflex

Central command _______________ activates muscle and cardiovascular system

Intent to exercise

Cardiovascular center decreases __________ nerve activity and increases ___________ nerve activity during exercise

parasympathetic, sympathetic

_____________ mechanism (from brain to cv system) to start to increase O2 delivery

Feed forward

1. Exercise pressor reflex originates in muscle ​

2. Group III nerves sense contractions​

3. Group IV nerves sense metabolites ​

4. EPR is the “Feedback” mechanism to match O2 delivery to demand (signal from muscle)

Exercise pressor reflex

1. Baroreceptor located in aorta and carotid arteries ​

2. Baroreceptor send continuous feedback to cardiovascular control center ​

3. Goal: Adjust PNA and SNA to keep BP “constant” at level it needs to be during activity (BP always changing 120/80)​

Baroreflex

Blood Pressure Response to Exercise​

1. Systolic Blood pressure is pressure during left ventricular contraction (Determined by cardiac output= HR x SV (sv main determinant) ) ​

2. Diastolic BP is pressure using Left ventricular relaxation (determined primarily by systemic vascular resistance, secondary Determinant is heart rate ) stays constant due to cancelation partially goes down since arteries are dilating but heart rate goes up) ​

Blood Pressure Response to Exercise​

blood pressure response to exercise chart

how can BP increase if you have baroreceptors

The Operating point is reset to a higher pressure during exercise (in hypertensive patient OP will drop lower at rest after exercise than their original resting for about 12 hours )​