5.2 Heart Rate Flashcards Preview

A Level Biology > 5.2 Heart Rate > Flashcards

Flashcards in 5.2 Heart Rate Deck (27):
1

what is normal heart rate

70 beats per minute

2

is heart rate voluntary or involuntary?

involuntary

3

what nervous system controls heart rate?

autonomic

4

which area of the brain is responsible for controlling heart rate?

medulla oblongata

5

what are the 2 centres of the medulla oblongata?

cardiac excitatory
cardiac inhibitory

6

what does the cardiac excitatory centre do?

increases heart rate by sending impulses through sympathetic nerve to SAN

7

what does the cardiac inhibitory centre do?

decreases heart rate by sending impulses through parasympathetic nerve to SAN

8

which centre is stimulated is depends upon what?

information from receptors

9

what are baroreceptors? what do they detect?

pressure receptors detecting changes in blood pressure

10

where are baroreceptors found?

aorta
vena cava
cartoid arteries

11

what are chemoreceptors? what do they detect?

chemical receptors
detect changes in levels of chemicals within the blood

12

where are chemoreceptors found?

cartoid artery (supplies brain with blood)

13

what are chemoreceptors sensitive to changes in?

blood pH

14

if CO2 levels in the blood increase what happens to blood pH?

it decreases

15

why does blood pH decrease if CO2 levels increase?

CO2 interacts with H2O in the blood forming carbonic acid

16

when blood pH decreases chemoreceptors send an impulse to where?

medulla oblongata

17

(decrease in pH) response is coordinated in which centre? resulting in an impulse being sent where?

cardiac excitatory centre
along sympathetic nerve

18

(decrease in pH) from sympathetic nerve the impulse reaches the SAN causing what?

increase in heart rate

19

(decrease in pH) increase heart rate moves CO2 where?

away to the lungs in order to get rid of it

20

(decrease in pH) as the CO2 is exhaled from the lungs what happens to pH?

returns to normal

21

(decrease in pH) as pH returns to normal what happens?

change detected by chemoreceptors sends an impulse to medulla oblongata then to cardiac inhibitory centre sends an impulse down parasympathetic as no more increase needed.

22

increase in blood pressure is detected by what?

baroreceptors

23

(increase in bp) baroreceptors send messages to the.....

medulla oblongata

24

(increase in bp) the medulla oblongata sends an impulse to where?

cardiac inhibitory centre

25

(increase in bp) the cardiac inhibitory centre coordinates a response along where? resulting in what?

parasympathetic nerve leading to SAN
decrease in heart rate until bp returns to normal

26

(increase in bp) when bp returns to normal what happens?

baroreceptor sends message to medulla oblongata then to cardiac excitatory centre as decrease is no longer needed

27

when might more CO2 be produced?

exercising

Decks in A Level Biology Class (102):