6: Heart Rate

Question 1

What is the peripheral nervous system?

Answer 1

The neurones that connect the CNS to the rest of the body

Question 2

What is the peripheral nervous system split into?

Answer 2

The somatic and autonomic systems

Question 3

What is the somatic nervous system?

Answer 3

Controls conscious activities

Question 4

What is the autonomic nervous system?

Answer 4

Controls unconscious activities

Question 5

What is the autonomic system split into?

Answer 5

The sympathetic and parasympathetic nervous system

Question 6

What is the sympathetic nervous system?

Answer 6

‘fight or flight’
gets the body ready for action

Question 7

What is the parasympathetic nervous system?

Answer 7

‘rest and digest’
calms the body down

Question 8

Myogenic definition?

Answer 8

can contract and relax without receiving signals from nerves

Question 9

Where does the heart beat start?

Answer 9

The sinoatrial node (SAN)

Question 10

What is the sinoatrial node?

Answer 10

a small mass of tissue in the wall of the right atrium

Question 11

What does the sinoatrial node do?

Answer 11

Sets the rhythm of the heart rate by sending out regular waves of electrical activity to the atrial walls, causing the right and left atria to contract at the same time

Question 12

What prevents the electrical signal sent out from the SAN from being passed directly to the ventricles?

Answer 12

A band of non-conduction connective tissue

Question 13

Where are the waves of electricity from the SAN transferred?

Answer 13

The atrioventricular node (AVN)

Question 14

What does the AVN do?

Answer 14

Slight delay before the AVN reacts, passes electrical activity on to the bundle of His

Question 15

What is the bundle of His?

Answer 15

a group of muscle fibres responsible for conducting the waves of electrical activity between the ventricles to the apex

Question 16

What is the Purkyne tissue?

Answer 16

Finer muscle fibres in the right and left ventricle walls that splits off from the bundle of His

Question 17

What does the Purkyne tissue do?

Answer 17

Causes the ventricles to contract simultaneously from the bottom up

Question 18

How to remember the route of the waves of electrical activity?

Answer 18

Silly Ants Have Pants

Question 19

What part of the brain controls the rate at which the SAN fires?

Answer 19

The medulla oblongata

Question 20

What are the pressure receptors called?

Answer 20

Baroreceptors

Question 21

Where are baroreceptors found?

Answer 21

Aorta, carotid arteries

Question 22

What are the chemical receptors called?

Answer 22

Chemoreceptors

Question 23

Where are the chemoreceptors found?

Answer 23

Aorta, carotid arteries, medulla oblongata

Question 24

What do the chemoreceptors detect?

Answer 24

Oxygen level in the blood, pH, CO2

Question 25

What happens when high blood pressure is detected by baroreceptors?

Answer 25

Impulse sent along sensory neurone to medulla, medulla sends impulse along parasympathetic neurones, secrete acetylcholine, which binds to receptors on the SAN, heart rate slows

Question 26

What happens when low blood pressure is detected by baroreceptors?

Answer 26

Impulse sent along sensory neurone to medulla, medulla sends impulse along sympathetic neurones, secrete noradrenaline, binds to receptors on the SAN, heart rate speeds up

Question 27

What do chemoreceptors detect to lower the heart rate?

Answer 27

High blood oxygen, low CO2, high pH

Question 28

What do chemoreceptors detect to increase the heart rate?

Answer 28

Low oxygen, high CO2, low pH