Heart 6, External modification of cardiac output

Heart rate is generated internally by the sinoatrial node, but it is modified to meet homeostatic requirements, by activity of the autonomic nervous system and some hormonal physiology.

External modification of contractility MCQs, please leave answers in the comments section for marking.

1. The cardiac autonomic centre is located in the;

a. cerebral cortex

b. occipital lobe

c. pons

d. medulla oblongata

e. spinal cord

2. Sympathetic neurological stimulation of the heart, via cardiac accelerator nerves travels to the heat via the

a. cervical spinal nerves

b. thoracic spinal nerves

c. vagus nerves

d. left glossopharyngeal nerve

3. Sympathetic activity stimulates the sinoatrial node and atrioventricular node via the chemical transmitter:

a. serotonin (5HT)

b. noradrenaline

c. acetylcholine

d. glutamate (glutamic acid)

e. GABA

4. Choose one true statement;

a. parasympathetic stimulation dilates the coronary arteries

b. noradrenaline stimulates (agonises) beta 1 adrenergic receptors

c. acetylcholine stimulates (agonises) beta 1 adrenergic receptors

d. sympathetic stimulation will slow the rate of electrical transmission through the atrioventricular node

e. none of the above

5. Choose one true statement;

a. cardiac output can be always be maintained if venous return is reduced

b. a positive inotropic effect will reduce cardiac output

c. sympathetic stimulation will constrict coronary arteries

d. increased heart rate is a chronotropic effect

e. increased strength of ventricular contraction is a chronotropic effect