Organisms Response to Change - Heart Rate

Question 1

what does the central nervous system consist of?

Answer 1

brain and spinal cord

Question 2

what is the peripheral nervous system?

Answer 2

nerves found outside CNS

Question 3

what are the 3 types of neurone?

Answer 3

sensory

motor

relay

Question 4

what is the role of a sensory neurone?

Answer 4

carry nerve impulses from a receptor to a coordinator

Question 5

what is the role of a motor neurone?

Answer 5

carry nerve impulses from the coordinator to the effector

Question 6

what is the role of a relay neurone?

Answer 6

connect sensory and motor neurones

Question 7

what are reflex actions?

Answer 7

automatic, rapid responses that do not involve conscious areas of the brain

Question 8

what does the autonomic nervous system consist of?

Answer 8

sympathetic nervous system

parasympathetic nervous system

Question 9

what is the role of the sympathetic nervous system?

Answer 9

fight or flight response

Question 10

describe the fight or flight response

Answer 10

stimulate effectors and speeds up activities

controls response to stressful situations

heightened awareness

Question 11

what is the role of the parasympathetic nervous system?

Answer 11

rest and digest

Question 12

describe the rest and digest response

Answer 12

inhibits effectors and slows down activities

controls activities in normal, restful conditions

conserves energy and replenishes body’s reserves

Question 13

describe the process of the a heartbeat

Answer 13

wave of electrical excitation spreads out from sinoatrial node causing both atria to contract

wave reaches the atrioventricular node

short delay at AV node

signal passes down bundle of his to purkyne fibres

wave of excitation released from purkyne tissues causing ventricles to contract from base upwards

Question 14

label this diagram of the heart

Answer 14

a - right atrium

b - sinoatrial node

c - atrioventricular node

d - atrioventricular bundle

e - left atrium

f - purkyne fibres

Question 15

what part of the brain controls heart rate?

Answer 15

medulla oblongata

Question 16

what centre increases heart rate?

Answer 16

cardioacceleratory centre

Question 17

what centre decreases heart rate?

Answer 17

cardioinhibitory centre

Question 18

how is the cardioacceleratory centre linked to the sinoatrial node?

Answer 18

sympathetic nervous system

Question 19

how is the cardioinhibitory centre linked to the sinoatrial node?

Answer 19

parasympathetic nervous system

Question 20

what is the medulla oblongata?

Answer 20

region of the brain that controls heart rate

Question 21

what are chemoreceptors?

Answer 21

receptors in carotid arteries that detect change in pH of blood

Question 22

what are baroreceptors?

Answer 22

receptors in carotid arteries and aorta that detect change in blood pressure

Question 23

what are carotid arteries?

Answer 23

arteries in the brain

Question 24

how does increase in rate of respiration lead to a change in the pH of blood?

Answer 24

increased respiration = more CO₂ produced

more CO₂ to carbonic acid in blood

pH lowers

Question 25

describe how decrease in blood pH leads to increase in heart rate

Answer 25

decrease in blood pH detected by chemoreceptors

more impulses sent to cardioacceleratory centre from chemoreceptors

more impulses to sinoatrial node via sympathetic nervous system

sinoatrial node increases heart rate

Question 26

how does an increase in heart rate increase the pH of blood?

Answer 26

more CO₂ removed in lungs

pH increases

Question 27

describe how an increase in blood pH leads to a decrease in heart rate

Answer 27

pH increase detected by baroreceptors

more impulses sent to cardioinhibitory centre

more impulses sent to sinoatrial node via parasympathetic nervous system

sinoatrial node decreases heart rate