Autonomic Nervous System (ANS) Functions and Structure

Flashcards covering key concepts and facts related to the Autonomic Nervous System (ANS) from the lecture notes.

What does the sympathetic division prepare the body for?

Fight or flight responses.

What are the main functions of the parasympathetic division?

Controls routine maintenance functions, also known as rest and digest.

How does sympathetic activation affect heart rate?

It increases heart rate.

Which neurotransmitter is released by postganglionic axons in the sympathetic division?

Norepinephrine.

Which neurotransmitter is released by postganglionic axons in the parasympathetic division?

Acetylcholine (ACh).

What is the cranial outflow of the parasympathetic division?

Originates from the brain and innervates organs of the head, neck, thorax, and abdomen.

Which cranial nerve innervates smooth muscles in the eyes?

Oculomotor Nerve (III).

What function does the vagus nerve serve in the parasympathetic division?

Innervates visceral organs of the thorax and abdomen, stimulates digestion, and decreases heart rate.

What is the difference between sympathetic and parasympathetic fibers in terms of branching?

Sympathetic fibers are highly branched, while parasympathetic fibers have few branches.

What do the gray rami contain?

Postganglionic fibers traveling to peripheral structures.

Where are the cell bodies of the cranial nerves located for parasympathetic outflow?

In ganglia associated with respective nerves.

What is referred pain?

Pain felt in areas different from the actual source, due to shared pathways in the spinal cord.

What role does the adrenal medulla play in sympathetic activation?

Acts as a modified sympathetic ganglion, secreting norepinephrine and epinephrine for a widespread response.

What is the primary integration center of the ANS?

The hypothalamus.

What are the two divisions of the autonomic nervous system?

Sympathetic and Parasympathetic divisions.

What type of control do the functions of the ANS exhibit?

Involuntary control.

What type of muscle do autonomic nerves primarily control?

Smooth and cardiac muscle.

What is the embryonic origin of the ANS?

It develops from the neural tube and neural crest.

What is the function of visceral sensory neurons?

They monitor sensations within the visceral organs such as stretch, temperature, and chemical changes.

What do the visceral reflexes involve compared to spinal reflexes?

Visceral reflexes are integrated in the brainstem and involve cranial nerves, whereas spinal reflexes involve spinal interneurons.

What is the basic organization of the sympathetic division?

Thoracolumbar division, issuing from lumbar regions.

What is the function of the pelvic splanchnic nerves in the parasympathetic division?

Innervate pelvic and lower abdominal organs.

What phenomenon does the enteric nervous system trigger?

Movement in the gastrointestinal tract when food is ingested.

How do sympathetic pathways differ from parasympathetic pathways?

Sympathetic pathways involve more branching and longer postganglionic fibers.

How does pregnancy affect the enteric nervous system functionality?

Pregnancy can lead to constipation due to reduced GI tract mobility.

What type of muscle does the somatic nervous system control?

Skeletal muscle.

What major functions are controlled by the hypothalamus in relation to the ANS?

Heart rate, blood pressure, digestion, and temperature regulation.

What type of neurons assist in the communication within the enteric nervous system?

Three-neuron arcs contained within the digestive tract.

What is the role of the cranial nerves in the parasympathetic division?

Stimulate secretion of glands and innervate various organs.

What is the relationship between sympathetic and parasympathetic divisions regarding neurotransmitters?

Both use ACh at the preganglionic synapse, but different neurotransmitters at the postganglionic level.

What happens to blood vessels under sympathetic activation?

They dilate to supply blood to skeletal muscles.

What does the hypogastric plexus innervate?

Pelvic organs and provides sympathetic innervation to the abdomen.

Describe the postganglionic fiber length in the sympathetic division.

They are long postganglionic fibers.

Describe the organization difference between sympathetic trunk ganglia and collateral ganglia.

Sympathetic trunk ganglia are paired and segmentally arranged; collateral ganglia are unpaired and located in the abdomen and pelvis.

How do sensory neurons in the ANS link to pain sensation?

They can share pathways with somatic sensory neurons, leading to referred pain.

What are some visceral reflex activities integrated in the brainstem?

Blood pressure regulation and responses to emotional stimuli.

How does the sympathetic division influence blood glucose levels?

It increases the release of glucose.

What is the first ganglion in the chain for sympathetic fibers?

Chain ganglia.

Which ganglion is involved in the secretion of tears and saliva?

Pterygopalatine ganglion.

What is one important effect of the vagus nerve on heart rate?

It decreases heart rate.

What happens to the pupils during sympathetic activation?

The pupils dilate.

What bodily functions does the sympathetic division inhibit?

Digestion and elimination processes.

Name the fibers that connect the sympathetic trunk to peripheral structures.

Rami communicantes.

What is the function of the glossopharyngeal nerve in the parasympathetic division?

Stimulates secretion of the parotid gland.

Which sympathetic pathway involves increasing heart rate and dilating bronchi?

Thoracic pathways.

What is the spinal origin for the parasympathetic division?

Craniosacral outflow.

What is one result of parasympathetic activation on bodily functions?

It promotes housekeeping activities like digestion.