Nervous Control [Cardiac and Ventilation] Flashcards
How is oxygen supply maintained in the body? 3
- Deeper breathing
- Faster breathing
- Increased cardiac output
Is heart rate controlled unconsciously/consciously?
Unconsciously
What is heart rate controlled by?
Cardiovascular control centre in medulla oblongata
How does the medulla oblongata set heartbeat rhythm?
- Controls rate at which SAN fires
- Generates electrical impluses
- Causes atria to contract
- Sets rhythm of heartbeat
What does heart rate alter in response to?
Internal stimuli
What are the 2 types of impulses?
Baroreceptors and chemoreceptors
What type of receptor are baroreceptors?
Pressure receptors
What type of receptor are chemoreceptors?
Chemical receptors
Where are baroreceptors found?
In the aortic and carotid bodies
Where are chemoreceptors found?
In the aortic and carotid bodies and medulla oblongata
What stimulates the baroreceptors?
High or low blood pressure
What stimulates the chemoreceptors?
Oxygen blood levels
What are 2 indicators of oxygen levels?
carbon Dioxide levels and pH levels
What is the automatic nervous system?
Nervous system operating without conscious control
What are the two types of nerves in the ANS?
- Sympathetic nerve
- Parasympatheic nerve - vagus nerve
What type of nerve is the sympathetic nerve?
An accelerator
What type of nerve is the parasympathetic nerve?
A deccelerator
What does the sympathetic nerve do?
Gets body ready for action
What does the parasympathetic nerve do?
Calms the body down
What does the sympathetic nerve do in heart rate?
- Stimulates SAN
- Increases heart rate during exercise
What does the parasympathetic nerve do in heart rate?
- Inhibits SAN
- Decreases heart rate after exercise
How does the body and heart rate respond to high blood pressure? 6
- 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
How does the body and heart rate respond to low blood pressure? 6
- 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
What indicators does the sympathetic nerve respond to?
- High blood CO2
- Low blood O2
- Low pH levels
What indicators does the parasympathetic nerve respond to?
- High blood O2
- Low blood CO2
- High pH levels
Describe the entire process of controlling heart rate during exercise - 14
- 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
What other hormone is involved in control of heart rate?
Adrenaline
How is adrenaline involved in the heart rate? 3
- Affects SAN
- Dilates arterioles going to skeletal muscles
- Constricts those going to digestive system
Where does control of ventilation occur?
Ventilation centre in medulla oblongata
How is the breathing process controlled? 13
- 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
How is breathing rate controlled? 11
- 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
In exercise, what else other than the chemoreceptors sends impulses to the medulla oblongata?
- Stretch receptors in muscles and tendons
- Send nerve impulses to the motor cortex
- Sends impulses to the medulla oblongata
