AUTONOMIC NERVOUS SYSTEM PHYSIOLOGY

Fig. 9.1 P. 220

Divisions of the ANS mobilizes the body during extreme situations Sympathetic “fight or flight” Parasympathetic performs maintenance activities and conserves body energy “resting and digesting”

Role of the Sympathetic Division Involves E activities – exercise, excitement, emergency, and embarrassment Promotes adjustments during exercise – blood flow to organs is reduced, flow to muscles is increased Its activity is illustrated by a person who is threatened –Heart rate increases, and breathing is rapid and deep –The skin is cold and sweaty, and the pupils dilate

Role of the Parasympathetic Division Involves the D activities – digestion, defecation, and diuresis Its activity is illustrated in a person who relaxes after a meal –Blood pressure, heart rate, and respiratory rates are low –Gastrointestinal tract activity is high –The skin is warm and the pupils are constricted

Fig. 9.6 P. 226

Fig. 9.2 P. 222

Fig. 9.3 P. 223

Fig. 9.4 P. 224

Fig. 9.5 P. 225

Fig. 9.7 P. 228

Fig. 9.8 P. 229

Fig. 9.9 P. 229

Adrenergic Receptors There are two major classes of adrenergic receptors: alpha and beta. Both operate through second messengers. Two subclasses of alpha receptors: –  1 - On post-synaptic membrane; increases cytoplasmic Ca 2+ ; excitatory at smooth muscle –  2 - On pre-synaptic membrane; involved in feedback inhibition

Adrenergic Receptors Two subclasses of beta receptors: –  1 - Found in the heart and kidney; involved in heart rate acceleration, and renin secretion. –  2 - Found in smooth muscle of arterioles at skeletal muscle, heart and viscera, plus smooth muscle of bronchioles; involved in vasodilation and dilation of bronchioles.

Fig P. 223

Table. 9.7 P. 234