Nervous Control [Cardiac and Ventilation]

Question 1

How is oxygen supply maintained in the body? 3

Answer 1

• Deeper breathing
• Faster breathing
• Increased cardiac output

Question 2

Is heart rate controlled unconsciously/consciously?

Answer 2

Unconsciously

Question 3

What is heart rate controlled by?

Answer 3

Cardiovascular control centre in medulla oblongata

Question 4

How does the medulla oblongata set heartbeat rhythm?

Answer 4

• Controls rate at which SAN fires
• Generates electrical impluses
• Causes atria to contract
• Sets rhythm of heartbeat

Question 5

What does heart rate alter in response to?

Answer 5

Internal stimuli

Question 6

What are the 2 types of impulses?

Answer 6

Baroreceptors and chemoreceptors

Question 7

What type of receptor are baroreceptors?

Answer 7

Pressure receptors

Question 8

What type of receptor are chemoreceptors?

Answer 8

Chemical receptors

Question 9

Where are baroreceptors found?

Answer 9

In the aortic and carotid bodies

Question 10

Where are chemoreceptors found?

Answer 10

In the aortic and carotid bodies and medulla oblongata

Question 11

What stimulates the baroreceptors?

Answer 11

High or low blood pressure

Question 12

What stimulates the chemoreceptors?

Answer 12

Oxygen blood levels

Question 13

What are 2 indicators of oxygen levels?

Answer 13

carbon Dioxide levels and pH levels

Question 14

What is the automatic nervous system?

Answer 14

Nervous system operating without conscious control

Question 15

What are the two types of nerves in the ANS?

Answer 15

• Sympathetic nerve

- Parasympatheic nerve - vagus nerve

Question 16

What type of nerve is the sympathetic nerve?

Answer 16

An accelerator

Question 17

What type of nerve is the parasympathetic nerve?

Answer 17

A deccelerator

Question 18

What does the sympathetic nerve do?

Answer 18

Gets body ready for action

Question 19

What does the parasympathetic nerve do?

Answer 19

Calms the body down

Question 20

What does the sympathetic nerve do in heart rate?

Answer 20

• Stimulates SAN

- Increases heart rate during exercise

Question 21

What does the parasympathetic nerve do in heart rate?

Answer 21

• Inhibits SAN

- Decreases heart rate after exercise

Question 22

How does the body and heart rate respond to high blood pressure? 6

Answer 22

• Baroreceptors detect high blood pressure
• Nervous impulses send impulses along parasympathetic nerves
• Sent to cardiovascular control centre
• Acetylcholine [neurotransmitter binds to receptor on SAN
• Fires impulses less frequently
• Slows heart rate and reduces blood pressure back to normal

Question 23

How does the body and heart rate respond to low blood pressure? 6

Answer 23

• Baroreceptors detect low blood pressure
• Nerve impulses sent along sympathetic nerve
• Sent to cardiovascular control centre
• Noraadrenaline binds to receptors on SAN
• SAN fires impulses more frequently
• Increases heart rate and blood pressure back to normal

Question 24

What indicators does the sympathetic nerve respond to?

Answer 24

• High blood CO2
• Low blood O2
• Low pH levels

Question 25

What indicators does the parasympathetic nerve respond to?

Answer 25

- High blood O2 - Low blood CO2 - High pH levels

Question 26

Describe the entire process of controlling heart rate during exercise - 14

Answer 26

- Stimulus of exercise - Skeletal muscles contract - Stimulates stretch receptors in the muscles and tendons - Impulses sent to cardiovascular control centre - Heart rate increases - Stroke volume increases - SAN activity increases - AVN time delay increases - Ventricles contract with greater force - Cardiac output increases - Blood pressure increases - Batoreceptors sent nerve impulses to CCC - Inhibitory nerve impulses to SAN - Prevents rise in heart rate

Question 27

What other hormone is involved in control of heart rate?

Answer 27

Adrenaline

Question 28

How is adrenaline involved in the heart rate? 3

Answer 28

- Affects SAN - Dilates arterioles going to skeletal muscles - Constricts those going to digestive system

Question 29

Where does control of ventilation occur?

Answer 29

Ventilation centre in medulla oblongata

Question 30

How is the breathing process controlled? 13

Answer 30

- Inspiratory centre in the medulla oblongata sends nerve impulses to intercoastal and diaphragm muscles to make contract - Also sends impulses to expiratory centre inhibiting its action - Increases volume of lungs - Decreases pressure of lungs - Air enters lungs due to pressure difference - As lungs inflate, stretch receptors in bronchioles are stimulated - Send nerve impulses back to medulla oblongata - Inhibit action of inspiratory centre - Expiratory centre sends impulses to diaphragm and intercoastal muscles - They relax - Causes lungs to deflate, expelling air - Stretch receptors become inactive - Inspiratory centre no longer inhibited and cycle starts again

Question 31

How is breathing rate controlled? 11

Answer 31

- CO2 levels increase - CO2 dissolves in blood plasma to make carbonic acid - Accumulates as hydrogen ions - lowers pH of blood - Chemoreceptors sensitive to pH in: 1] Medulla oblongata 2]Aortic bodies 3]Carotid bodies - Detect decrease in pH - Send nerve impulses to medulla oblongata - Sends more frequent nerve impulses to diaphragm and intercoastal muscles - Increases rate and depth of breathing - Gaseous exchange rate increases - CO2 is removed and extra O2 supplied to muscles - Decrease in breathing rate and depth

Question 32

In exercise, what else other than the chemoreceptors sends impulses to the medulla oblongata?

Answer 32

- Stretch receptors in muscles and tendons - Send nerve impulses to the motor cortex - Sends impulses to the medulla oblongata