Controlling Heart Rate Flashcards
What are the important reasons for the circulatory system?
Transport of oxygen and nutrients, such as glucose, fatty acids and amino acids to the tissues.
Removal of waste products, such as CO2 from the tissues to prevent accumulation that may become toxic
Transport of urea from the liver to the kidneys.
Distribute heat around the body or deliver it to the skin surface to be radiated away.
How can the heart action be modified?
Raising or lowering of HR
Altering the force of contraction of ventricle walls
Altering the stroke volume
What is the stroke volume?
The volume of blood pumped per beat.
What does myogenic mean?
That the muscle can initiate its own beat at regular intervals.
What is the SAN?
A region of tissue that can initiate an action potential.
At rest what is the HR controlled by?
The SAN
What is the frequency of the waves of excitation altered by?
The cardiovascular centre in the medulla oblongata.
How is HR increased by the sympathetic system?
Action potentials sent down the accelerans nerve causes the release of neurotransmitter noradrenaline at the SAN.
What nerve reduces HR?
The vagus nerve.
What are the sensory inputs of the CCC?
Stretch receptors
Chemoreceptors.
What do stretch receptors do?
They detect the movement of the limbs. These send impulses to the CVC, informing it that extra O2 may soon be needed. This leads to an increased HR.
What do the chemoreceptors in the carotid artery do?
Monitor the pH of the blood.
What can be fitted as a method for artificially controlling the heart?
A pacemaker.
