Question

1. list the major structures innervated by the sympathetic division and the effects on each structure
2. compare and contrast visceral and somatic reflex arcs;
3. compare and contrast the effects of the parasympathetic and sympathetic divisions on the iris, heart, airways, GI tract and urinary system;
4. apply knowledge of the autonomic nervous system to practical, problem-solving situations;
5. predict the effect of anatomical and physiological changes in the autonomic nervous system on the body; and
6. relate the effects of selected drugs to changes in parasympathetic or sympathetic activity.

Answer 1

1).

The sympathetic nervous system is also called as the thoraco-lumbar division, as it contains the preganglionic neurons of the thoraco-lumbar outflow. The sympathetic nervous system is concerned with preparing the organism for emergency (fight or flight).

1Q).

Epinephrine and norepinephrine are the endocrinal secretions of adrenal medulla of the adrenal gland. Norepinephrine is the neurotransmitter that is released at the effector organ (postganglionic end) innervated by the sympathetic nervous system. The different types of adrenergic receptors are,

• Alpha 1 receptors
• Alpha 2 receptors
• Beta 1 receptors
• Beta 2 receptors

The effect of sympatho-adrenal stimulation on different organs:

Organ	Action	receptor
Eye	Contraction of pupil	Alpha 1
Heart	Increased rate and force of contraction	Beta 1
Vascular smooth muscle of skin and splanchnic vessels	Contraction	Alpha and beta
Skeletal muscle vessels	relaxation	Beta 2
Bronchial smooth muscle	relaxation	Beta 2
Gastrointestinal tract	Relaxation of walls, inhibition of secretions, sphincters constriction	Alpha and beta
Male copulatory structure	Ejaculation	Alpha 1
Genitourinary smooth muscle	Contraction of urethral sphincter	Alpha 1
	Relaxation of uterine muscle in pregnant women	Beta 2
	Relaxation of bladder wall	Beta 2
Sweat glands	Increase sweat production	Alpha 1