18. The Heart

What is the primary function of the pacemaker cells in the SA node in the heart?

Which structure or structures are most directly responsible for allowing contraction of the ventricles to begin at the apex of the heart rather than in the septum closer to the AV node?

Which center in the medulla oblongata controls the sympathetic neurons that stimulate the heart?

Which statement best describes a difference between how the sympathetic and parasympathetic nervous system affects the heart?

The autonomic division of the nervous system directs

(a) Voluntary motor activity

(b) Conscious control of skeletal muscles

(c) Unconscious control of skeletal muscles

(d) Processes that maintain homeostasis

(e) Sensory input from the skin

Which four ganglia serve as origins for postganglionic fibers involved in control of visceral structures in the head?

Describe the pericardium and distinguish between the fibrous and the serous pericardia relative to histological structure and location.

Why is autonomic tone a significant part of ANS function?

How do pacemaker cardiac muscle cells differ from contractile cardiac muscle cells? What is autorhythmicity?