Heart

Question 1

Myogenic

Answer 1

Cardiac muscle can contract on its own no stimulus

Question 2

Rate of contraction

Answer 2

Controlled by nervous system - waves of electrical activity

Question 3

How do chemoreceptors control heat rate

Answer 3

If increased muscular/metabolic activity the more co2 produced by tissues from increased respiration so blood PH is lowered. Chemical receptors in carotid arteries increase frequency of impulses to the medulla oblongata so the centre of it speeds HR, increases frequency of impulses to SAN node via sympathetic nervous system, the SAN node then increases HR so increased blood flow removes co2 faster so the conc of co2 returns to normal

Question 4

Pacemakers other name

Answer 4

Sinoatrial node SAN

Question 5

Layers of non conductive tissue that prevent the wave for controlling HR from crossing into ventricles

Answer 5

Atrioventricular septum

Question 6

Group of cells that lies between atria in control of HR

Answer 6

Atrioventricular node AVN

Question 7

Muscle fibres involved in control of HR

Answer 7

Purkyne tissue which make up the bundle of His

Question 8

Changes to the HR are controlled by this region of the brain

Answer 8

Medulla oblongata