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Control of heart rate

53 flashcardsby Logan
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1
What generates electrical impulses in the heart?
Sinoatrial node (SAN)
2
What does SAN stand for?
Sinoatrial node
3
What is the function of the SAN?
Generates electrical impulses
4
How is heart rate controlled?
Unconsciously by the brain
5
What part of the brain controls heart rate?
Medulla
6
What type of receptors detect blood pressure?
Pressure receptors
7
What type of receptors detect oxygen levels?
Chemical receptors
8
Where are pressure receptors located?
Aorta and carotid arteries
9
What happens when blood pressure is high?
Impulses sent to medulla
10
What does the medulla do during high blood pressure?
Decreases heart rate
11
What happens when blood pressure is low?
Impulses sent to medulla
12
What does the medulla do during low blood pressure?
Increases heart rate
13
Where are chemical receptors located?
Aorta, carotid arteries, medulla
14
What do chemical receptors detect?
Oxygen, carbon dioxide, pH levels
15
What happens during low oxygen or low pH?
Heart rate increases
16
What happens during high oxygen or high pH?
Heart rate decreases
17
What carries impulses to the SAN?
Autonomic nervous system
18
What ensures the heart rate adjusts to demand?
Pressure and chemical receptors
19
What is cardiac muscle described as?
Myogenic
20
What does myogenic mean?
Contracts without nerve signals
21
What controls atrial contraction?
SAN impulses
22
What controls ventricular contraction?
AVN (atrioventricular node)
23
What does AVN stand for?
Atrioventricular node
24
What does the bundle of His do?
Conducts electrical signals
25
Where does the bundle of His transmit signals?
To Purkyne tissue
26
What does Purkyne tissue do?
Conducts impulses to ventricle walls
27
Where does ventricular contraction start?
From the bottom upwards

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28
What causes heart rate to change?
Signals detected by receptors
29
What do pressure receptors detect?
High or low blood pressure
30
Where are pressure receptors found?
Aorta and carotid arteries
31
What do chemical receptors detect?
Oxygen, carbon dioxide, and pH
32
Where are chemical receptors located?
Aorta, carotid arteries, and medulla
33
What happens during high blood pressure?
Receptors send signals to medulla
34
How does the medulla respond to high blood pressure?
Sends impulses to decrease heart rate
35
What happens during low blood pressure?
Receptors send signals to medulla
36
How does the medulla respond to low blood pressure?
Sends impulses to increase heart rate
37
What happens during high blood oxygen or pH?
Receptors signal medulla to decrease heart rate
38
What happens during low blood oxygen or pH?
Receptors signal medulla to increase heart rate
39
Which system carries signals to the SAN?
Autonomic nervous system
40
What does the sympathetic nervous system do?
Increases heart rate
41
What does the parasympathetic nervous system do?
Decreases heart rate

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42
What coordinates changes in heart rate?
Medulla oblongata
43
What are the two types of autonomic nervous system pathways?
Sympathetic and parasympathetic
44
What neurotransmitter does the sympathetic system release?
Noradrenaline
45
What neurotransmitter does the parasympathetic system release?
Acetylcholine
46
What effect does noradrenaline have?
Increases SAN activity
47
What effect does acetylcholine have?
Decreases SAN activity

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48
What is the function of the bundle of His?
Conducts impulses to ventricles
49
What is the Purkyne tissue’s role?
Causes ventricles to contract

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50
What are the effects of high CO2 in the blood?
Heart rate increases
51
What detects high CO2 levels?
Chemical receptors
52
Why does high CO2 increase heart rate?
To remove CO2 faster from blood
53
What happens to CO2 during low heart rate?
It builds up in the blood
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