9.3 Control of Heart Rate

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  • Created by: Molly
  • Created on: 07-03-14 13:30
What are the two nervous systems?
The sympathetic nervous system and the parasympathetic nervous system.
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What is the sympathetic nervous system responsible for?
Stimulates effectors and so SPEEDS UP ACTIVITY.
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What is the parasympathetic nervous system responsible for?
Inhibits effectors and so SLOWS DOWN ACTIVITY.
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The actions of the 2 nervous systems are........?
Antagonistic.
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What does antagostic mean?
They oppose each other.
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Which part of the brain controls changes to the heart rate?
The Medulla Oblongata.
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What is the sinoatrial node?
specialised tissue in the heart which controls heart rate.
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There are two types of information which stimulate changes to heart rate. What are they?
Chemical changes in the blood and pressure changes in the blood.
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What are chemoreceptors and where are they found?
Chemoreceptors are a response to the pH of the blood and are found in the wall of the CARTOID arteries.
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Which part of the body does the CARTOID artery serve?
The brain.
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What happens to the blood when there are increased levels of Carbon Dioxide present?
The pH of the blood is lowered because carbon dioxide is acidic.
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How do chemoreceptors increase the heart rate?
When high conc. of CO2 is present pH is lowered. Chemoreceptors in wall of CARTOID artery detect this and increase frequency of nerve impulses to the MEDULLA OBLONGATA which increases heart rate.
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How do chemoreceptors decrease the heart rate?
Increased flow of blood leads to removal of CO2 from the blood which once again raises the pH. Chemoreceptors then reduce the frequency of nerve impulses to MEDULLA OBLONGATA, which reduces frequency of nerve impulses to the SAN, decreases heart rate
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Where do pressure receptors occur?
In the wall of the cartoid arteries.
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What happens when blood pressure is higher than normal?
The pressure receptors transmit a nervous impulse to the medulla oblongata that decreases heart rate (parasympathetic).
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What happens when blood pressure is lower than normal?
The pressure receptor sends nerve impulses to the medulla oblongata which increase heart rate (sympathetic).
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Other cards in this set

Card 2

Front

What is the sympathetic nervous system responsible for?

Back

Stimulates effectors and so SPEEDS UP ACTIVITY.

Card 3

Front

What is the parasympathetic nervous system responsible for?

Back

Preview of the front of card 3

Card 4

Front

The actions of the 2 nervous systems are........?

Back

Preview of the front of card 4

Card 5

Front

What does antagostic mean?

Back

Preview of the front of card 5
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