lect 16 pt 3

What is an example of a heightened parasympathetic state?

After a large meal, a person may feel very relaxed while digestion is active and the pupils are somewhat constricted.

How does the parasympathetic division affect peristalsis?

It stimulates peristalsis, the waves of smooth muscle contraction that move material through the digestive tract.

How does the parasympathetic division affect gland secretion?

It stimulates glands to secrete digestive enzymes and hormones that help with digestion.

How does the parasympathetic division affect defecation and urination?

It promotes defecation and urination, supporting the elimination of waste.

How does the parasympathetic division affect sexual function?

It stimulates sexual arousal and erection in both males and females, but not sexual climax.

How does the parasympathetic division affect the lacrimal and salivary glands?

It stimulates the lacrimal glands to produce tears and the salivary glands to produce saliva.

How does the parasympathetic division affect the pupils?

It constricts the pupils.

How does the parasympathetic division affect the bronchial tubes?

It causes bronchoconstriction by contracting smooth muscle in the bronchial tubes, making the airways narrower.

Why is bronchoconstriction compatible with a relaxed parasympathetic state?

During a relaxed state, the body generally does not need the increased oxygen intake required during intense activity.

How does the parasympathetic division affect heart rate?

It slows the heart rate, particularly when the heart is beating rapidly, helping return it toward a calmer state.

What functions do parasympathetic motor actions do?

• They support digestion,

• glandular secretion,

• elimination,

• sexual arousal,

• pupil constriction,

• and a calmer heart rate and respiratory state.

Why are increased digestive activity and a relaxed state associated with parasympathetic activity?

Functions such as peristalsis, digestive secretion, urination, and defecation are supported when the body is not prioritizing an emergency response.

What is the main functional state associated with the sympathetic division?

An emergency-response state commonly called “fight or flight,” sometimes expanded to “fight, flight, or fright.”

Where are sympathetic preganglionic neuron cell bodies located?

They are located in the thoracic and lumbar spinal cord.

Where do sympathetic preganglionic neurons synapse?

They synapse in vertebral chain (sympathetic trunk) ganglia or prevertebral collateral ganglia.

Which organs can receive sympathetic input through the vertebral chain ganglia?

The chain ganglia distribute sympathetic signals to effectors in the head, thorax, and pelvic regions, among other areas.

Which organs are primarily associated with the prevertebral collateral ganglia?

They distribute sympathetic signals to abdominal organs.

What is the general length arrangement of sympathetic neurons?

Short preganglionic neurons and long postganglionic neurons.

What does “fight or flight” describe?

It describes the body's response to danger or an emergency, preparing it to confront a threat or escape.

What does the phrase “fight, flight, or fright” add?

It also includes a fear response in which a person may freeze or become temporarily stuck rather than immediately fighting or fleeing.

How does the sympathetic division affect blood vessels?

It can cause vasoconstriction or vasodilation, depending on the blood vessels and the body's needs.

How does the sympathetic division affect heart rate and force?

It increases heart rate and the force of cardiac contractions, making the heart beat harder and faster.

How does the sympathetic division affect respiratory rate?

It increases respiratory rate so the body can take in more oxygen during heightened activity.

How does the sympathetic division affect peristalsis?

It inhibits peristalsis, reducing digestive activity while the body prioritizes an emergency response.

Why might sympathetic activity reduce digestion during an emergency?

The body redirects its priorities toward responding to danger rather than moving food through the digestive tract.

Why can hair stand on end during sympathetic activation?

Sympathetic signals activate the arrector pili muscles attached to hair follicles, causing the hairs to stand up.

What are arrector pili muscles?

They are small muscles associated with hair follicles that contract during sympathetic responses, making hairs stand on end.

How does the sympathetic division affect sweat glands?

It stimulates sweat glands to increase sweating.

How does the sympathetic division affect the bronchial tubes?

It causes bronchodilation, widening the airways to allow more air to enter with each breath.

Why is bronchodilation useful during sympathetic activation?

Wider airways allow more air and oxygen to enter the body, supporting increased physical activity.