the heart beat and cardiac cycle

Question 1

what is found on the wall of the right atrium

Answer 1

group of cells called the sino atrial nodes

Question 2

what does the san produce

Answer 2

critical stimulus for contraction occurs here

Question 3

what does the san have

Answer 3

a basic rhythm of stimulation which determines a heart eat

Question 4

how does the atria contract

Answer 4

the wave of electrical activity spreads out from the san across the atria which causes the atria to contract

Question 5

what is present between the atria and ventricle

Answer 5

a layer of non conductive tissue

Question 6

what does this prevent

Answer 6

the waves to be passed on to the ventricles

Question 7

where does the wave pass through next

Answer 7

the next group of cels called the atrioventricular knode between the atrias

Question 8

why is there a short delay in the avn

Answer 8

a short delay so that the ventricles can fill up with blood before it contracts

Question 9

what does the avn convey

Answer 9

electrical waves between the ventricle through muscle fibres called bundle of his

Question 10

what do bundle of his do to the wave

Answer 10

conduct it through the septum to the base of the ventricle

Question 11

what happens at the base of the ventricle

Answer 11

the bundle of his divide into the pakinje fibres

Question 12

what happens at these fibres

Answer 12

waves are reeased which causes the ventricle to contract forcing blood out of the ventricles base upwards

Question 13

what is a baroreceptor

Answer 13

detect a change in blood pressure in the aorta and the coronary artery

Question 14

what is the chemorecptor

Answer 14

detect a change in ph of the blood through the aorta and the corotoid artery

Question 15

what does is the medula oblangata

Answer 15

a reigion in the brain which controls the changes in heart beat

Question 16

in the centre which increase heart rate what is it linked to

Answer 16

the san and the sympathetic nervous system

Question 17

in the centre which decreases the heart rate what is it linked to

Answer 17

the san and the parasymphathetic pathway `

Question 18

what is the carotoid artery

Answer 18

the artery which carries blood to the brain

Question 19

when it detects a decrease in ph what does it cause

Answer 19

due to an increase in c02 (acidic) an increase of firing of nerve impulses to the medula oblangata

Question 20

what does the medula oblangata do

Answer 20

increases the number of impulses to the san via the sympathetic nervous system

Question 21

what doe sthis do at the san

Answer 21

increase the electrical waves which increase the heart rate

Question 22

what happens when the pressure is higher than norma;

Answer 22

nerve impulses are sent to the medula oblangata and then sends signals down the parasympathetic nerves to san slow down heart beat

Question 23

what happesn when the pressure decreases

Answer 23

nerve impulses are increased to medula oblnangata which then increase the nerve impulses to the san via the sympathetic nervous system to increase heart rate