cardiovascular response

Question 1

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Question 1

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Question 2

what does baroreceptor detect

Answer 2

Receptors detecting blood
pressure on beat to beat basis

Question 3

what is the medulla oblongata

Answer 3

Is the primary cardiovascular control centre

Question 4

baroreceptors and MAP

Answer 4

Baroreceptor firing frequency changes
with changes in blood pressure

Question 5

what does a fall in blood pressure cause

Answer 5

A fall in blood pressure causes the carotid and
aortic baroreceptors to detect a hypotensive
stimulus leading to decreases in afferent
baroreceptor nerve firing.

This reduction in neural input to the brainstem
causes a decrease in parasympathetic nerve
activity to the heart and an increase in
sympathetic outflow to the heart and vasculature.

The converse occurs with increases in blood
pressure

Question 6

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Question 7

how to work out MAP

Answer 7

MAP = CO X TOTAL PERIPHERAL RESISTANCE

Question 8

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Answer 8

4 factors and what they determine

Question 9

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Question 10

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Question 11

what is steady state exercise

Answer 11

the level of exercise at which the physiological responses remain
relatively stable for an extended period of time

Question 12

What determines if we can maintain steady-
state exercise?

Answer 12

The delivery of adequate oxygen to the exercising muscles,

The ability of the cells to utilise this oxygen in the aerobic process of
energy metabolism, and

The ability to eliminate heat.
During steady-state exercise the physiological responses of ventilation (VE), oxygen consumption ( VO2), and cardiac output (Q) are similar in the sense that they involve four phases

Question 13

how is their an increase in ventilation

Answer 13

that is, the motor cortex signals the respiratory control centre to increase ventilation)

Mechanoreceptors in the muscles and limbs detect limb movement and physical deformation, and further supplement central command

Question 14

what is the starling effect

Answer 14

When venous return of blood to the heart increases, the myofilaments (actin and myosin) in cardiac muscle are stretched to a more optimal overlap. As a result the strength of the contraction is greater, and therefore is increased.

The initial rapid rise in cardiac output is explained firstly bycentral command, and secondly by the Starling Effect.

Input from mechanoreceptors in muscles also contribute to the central command process by feedback control.

Chemoreceptors in muscle are mainly responsible for the secondary gradual rise to steady state

Question 15

what is metaboreflex

Answer 15

When exercise begins,
Muscle metabolism increases, metabolite
(e.g., lactic acid, potassium and
adenosine) accumulate in the working
muscle.

Receptors in the muscle detect this
accumulation and afferent fibres send
information to the brain (the medulla)
This increases sympathetic nerve activity

Question 16

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Question 17

describe the Redistribution of cardiac
output during exercise

Answer 17

Blood flow increases in skeletal muscle, the
skin and the heart

Skeletal Muscle:
Supply of oxygen and removal of
metabolic waste

Skin:
Dissipation of heat

Heart:
Oxygen supply (cardiac muscle extracts
almost all oxygen from blood even at rest

Blood flow decreases in the kidneys, digestive
tract and all other parts of the body not
directly involved in exercise.

Blood flow through the brain remains fairly
constant due to autoregulation. The fixed volume of the cranial cavity cannot accommodate large increases in blood flow.

Question 18

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