Sympathetic Functions Overview

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Questions and Answers

What response occurs when the photoreceptors in the retina are stimulated by light?

Miosis results from the activation of the Edinger Westphal nucleus. (correct)

Pupil dilation occurs.

Mydriasis occurs due to activation of the Edinger westphal nucleus.

Sympathetic functions are suppressed.

How does the hypothalamus influence autonomic functions?

It acts independently of the reticular formation and cerebral cortex.

It regulates vasomotor activity through emotional responses. (correct)

It only affects parasympathetic functions.

Autonomic nervous system is influenced by it reflexibly.

Which part of the brain stem controls cardiovascular functions like vasomotor activity?

The reticular formation. (correct)

The cerebellum.

The anterior hypothalamic nuclei.

The frontal cortex.

What effect does prolonged mental work have on the vasomotor center?

It stimulates the center potentially causing chronic hypertension. Signup and view all the answers

What happens when the arterial blood pressure is lowered significantly?

The sympathetic nervous system is stimulated to increase blood pressure up to normal level. Signup and view all the answers

What is the primary role of the sympathetic nervous system?

Preparation for stress responses Signup and view all the answers

Which of the following functions is temporarily inhibited by the sympathetic nervous system during an emergency?

Gastrointestinal motility Signup and view all the answers

What happens to the heart under parasympathetic control?

Decreased heart rate and force Signup and view all the answers

Which of the following statements is true about sympathetic functions?

They enhance respiratory passages for better oxygenation. Signup and view all the answers

What is the primary function of the parasympathetic nervous system?

To store and preserve energy Signup and view all the answers

During which state does the parasympathetic nervous system primarily function?

Sleep and rest Signup and view all the answers

Which system is responsible for mass discharge leading to widespread bodily responses?

Sympathetic nervous system Signup and view all the answers

What is the effect of sympathetic tone on organs during rest?

It allows for mild continuous activity. Signup and view all the answers

What maintains a resting heart rate of approximately 70-80 beats/minute?

Parasympathetic tone Signup and view all the answers

What occurs when there is a loss of sympathetic tone?

Rapid drop in arterial blood pressure Signup and view all the answers

Which of these is an example of spinal autonomic reflexes?

Micturition and defecation reflexes Signup and view all the answers

How can reflex salivary, gastric, and pancreatic secretion be initiated?

By introducing food in the mouth. Signup and view all the answers

What is the intrinsic heart rate of the heart when parasympathetic vagus nerves are cut?

100 beats/minute Signup and view all the answers

What type of control influences the autonomic nervous system from higher centers in the nervous system?

Descending impulses Signup and view all the answers

Which statement correctly describes parasympathetic tone?

It maintains smooth muscle tone in the intestines Signup and view all the answers

Which process involves stimulation of cranial parasympathetic centers?

Reflex salivary secretion Signup and view all the answers

Study Notes

Integration of Sympathetic Functions

Sympathetic nervous system prepares the body for stress, such as fear, fight, flight, exercise, or cold exposure.
Sympathetic functions are often integrated, with mass discharge leading to widespread responses throughout the body.

Integration Mechanisms

Eyes: Pupil dilation and exophthalmos (bulging eyes).
Cardiovascular system: Increased heart rate and force, increasing arterial pressure and blood flow to tissues.
Respiratory system: Bronchial dilation for better ventilation and oxygenation.
Blood vessels: Vasodilation (widening) in skeletal and cardiac muscles, vasoconstriction (narrowing) in other areas, shifting blood flow.
Skin: Increased sweating to regulate body temperature.
Spleen: Splenic capsule contraction increases blood circulation.
Liver: Glycogenolysis (breakdown of glycogen to glucose) and lipolysis (breakdown of fats) to supply energy and increase blood glucose and free fatty acids.
Other functions, like gastrointestinal motility, may be temporarily inhibited.

Parasympathetic Functions

Parasympathetic nervous system is involved in conserving energy.
Functions include slowing heart rate, increasing digestive system activity, and resting functions.

Sympathetic and Parasympathetic Tones

Both systems are active even during rest, with one typically being dominant in any given organ.
The tone allows the body to regulate activity in targeted organs.

Reflex Control of Autonomic Functions

Spinal autonomic reflexes: Occur through the spinal cord and control reflexes such as urination and defecation.
Brain stem autonomic reflexes: Control reflexes like salivation, gastric secretion, and pancreatic secretion.

Higher Control of Autonomic Functions

Reticular formation: Controls autonomic functions like heart rate and blood pressure.
Hypothalamus: The anterior part controls parasympathetic functions, and the posterior part controls sympathetic functions. The hypothalamus modifies the activity of autonomic centers in the brain stem.
Cerebral cortex: The cortex controls the hypothalamus and the reticular formation, affecting autonomic responses, like prolonged mental work leading to chronic hypertension. Thinking or anticipation of food can lead to responses (e.g. salivation) via the reflex pathway.

Reflex Pupilloconstriction

Light exposure triggers the pupillary light reflex, causing pupil constriction to protect the retina.

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Description

Explore the critical roles of the sympathetic nervous system in preparing the body for stress through integrated responses. This quiz covers mechanisms such as pupil dilation, increased heart rate, and more, highlighting how these functions support vital processes during stress.