Topic 7B Breathing And Heart

Question 1

What is the SA node

Answer 1

1. Pacemaker that controls HB

2. Sends out regular waves of electrical activity

Question 2

Define cardiac output

Answer 2

Total volume of blood pumped by a ventricle in a minute

Question 3

How is heart rate controlled

Answer 3

1. Unconsciously by cardiovascular centre in Medulla oblongata
2. Controls the rate at which SNA generates electrical impulses (cause atria to contract)

Question 4

What does the height of the wave indicate

Answer 4

Size of electrical charge/ strength of contraction

Question 5

How does your body respond to exercise

Answer 5

1. Muscles contract more frequently so more aerobic respiration
2. Increase depth and rate of breathing for more o2 and less Co2
3. Increase heart rate to deliver more o2 and glucose + remove Co2

Question 6

What is tidal volume

Answer 6

Normally 0.4dm*3

Question 7

State the function of collagen tissue in the heart

Answer 7

1. Non-conducting

2. Prevents wave of electrical activity being passed directly from atria to ventricles

Question 8

Why do animals need to be able to alter heart rate?

Answer 8

To be able to respond to internal stimuli

Question 9

Where does the signal go after AV node

Answer 9

Delay to let atria fully empty

Question 10

What is the stroke volume

Answer 10

Volume of blood pumped by one ventricle each time it contracts

Question 11

What are ECGs used for?

Answer 11

Doctors compare to normal trace to diagnose abnormal heart rhythms

Question 12

What is breathing rate

Answer 12

Breaths taken a minute

Question 13

Define myogenic

Answer 13

Can contract and relax without reviving signals from neurones

Question 14

Function of Prukyne fibres

Answer 14

Carry signal to muscular walls of ventricles causing them to contact from the bottom up

Question 15

What is the QRS complex?

Answer 15

Contraction (DP) of ventricles

Question 16

What is the T wave

Answer 16

Relaxation (RP) of ventricles

Question 17

Where is the Sino-atrial node?

Answer 17

Wall of right atrium

Question 18

What’s the equation for cardiac output

Answer 18

Co (cm3/ min) = heart rate (bpm) X stroke volume

Question 19

Describe expiration

Answer 19

1. Stretch receptors detect inflated lungs
2. Send impulse to medulla
3. Nerve impulse sent to relax diaphragm and intercostal muscles

Question 20

Describe breathing in (inspiration)

Answer 20

1. Intercostal muscles, pulling ribs up
2. Diaphragm contracts (flattens)
3. This increase volume in lungs, bringing pressure to lower than environment

Question 21

How does the medulla oblongata respond to information from receptors

Answer 21

Processes then sends impulses along sympathetic or parasympathetic nerve to SAN

Question 22

What is the P wave

Answer 22

Depolarisation (contraction) of the atria

Question 23

What is the function of the bundle of His

Answer 23

1. Muscle fibres conduct electricity to finer fibres called Purkyne fibres

Question 24

How does exercise trigger an increase in breathing rate

Answer 24

1. More Co2 in blood, lowers pH
2. Chemoreceptors in medulla and aorta sensitive to pH change
3. Impulse sent to medulla, causing it to send more frequent impulses to intercostal and diaphragm
4. Co2 drops , pH returns to normal

Question 25

What is respiratory minute ventilation

Answer 25

Volume of gas breathed in OR out in a minute

Question 26

How does an electrocardiograph work?

Answer 26

Records de/repolarisation

Question 27

What is the role of receptors on heart rate

Answer 27

1. Pressure receptors on aorta
2. Chemoreceptors in aorta and Medulla measure Co2 and pH
3. These send impulses to MO along sensory neurones

Question 28

What’s the equation for respiratory minute ventilation

Answer 28

Tidal volume X breathing rate = RMV

Question 29

Where is the signal directed after SA node

Answer 29

Atrioventricular node

Question 30

Why does cardiac output increase with exercise

Answer 30

Heart rate and stroke volume increase

Question 31

What is oxygen consumption

Answer 31

Volume of oxygen used