ANAT 3001 - Pathway & Autonomics

What are the two main divisions of the Autonomic Nervous System?

Parasympathetics and Sympathetics

What is the primary function of the posterior funiculus-medial lemniscal sensory pathway?

To carry information on fine touch, pressure, and conscious proprioception.

How many neurons are typically involved in sensory pathways?

2-3 neurons in a series.

What is the role of the upper motor neuron (UMN) in motor pathways?

It originates in the cerebral cortex and synapses with the lower motor neuron (LMN) or interneurons.

Where does the corticospinal tract originate?

In the pre-central gyrus (primary motor cortex).

What is the function of the corticospinal tract?

To control precise, skilled voluntary movements of skeletal muscle.

What happens to the axon of the primary neuron in the posterior funiculus-medial lemniscal pathway?

It ascends in the posterior funiculus to the medulla oblongata.

What is the function of the sympathetic division of the autonomic nervous system?

To prepare the body for 'fight or flight' responses.

What is the function of the parasympathetic division of the autonomic nervous system?

To promote 'rest and digest' activities.

What type of sensory information is carried by the spinothalamic tract?

Pain, temperature, and crude touch.

What distinguishes somatic sensory neurons from visceral sensory neurons?

Somatic sensory neurons provide localized sensations, while visceral sensory neurons provide unlocalized sensations.

What is the pathway for motor output in the nervous system?

Motor output travels through descending pathways from the brain to targets in the body.

What is the role of the lower motor neuron (LMN)?

It carries motor information from the spinal cord to the target muscles or glands.

What are the two types of pathways in white matter of the spinal cord?

Ascending tracts and descending tracts.

What is the function of visceral motor innervation?

To regulate involuntary functions such as heart rate, digestion, and glandular activity.

What is the difference between presynaptic and postsynaptic neurons in the autonomic nervous system?

Presynaptic neurons (preganglionic) originate in the CNS, while postsynaptic neurons (postganglionic) are located in autonomic ganglia.

What type of muscle does the sympathetic division primarily target?

Smooth muscle, cardiac muscle, and glands.

What is the significance of the decussation of axons in the corticospinal tract?

It allows motor control from one side of the brain to affect the opposite side of the body.

What are funiculi in the context of the spinal cord?

Functionally distinct regions of white matter that contain multiple tracts.

What is the primary sensory cortex's location?

In the postcentral gyrus of the brain.

What type of information do ascending pathways carry?

Sensory information from the body to the brain.

What is the role of the thalamus in sensory pathways?

It acts as a relay station for sensory information before it reaches the cortex.

How does the autonomic nervous system regulate body functions?

It operates below the conscious level, controlling functions like heart rate and digestion.

What type of pathway do somatic motor neurons follow?

A single neuron pathway from the CNS to skeletal muscles.

What is the role of the dorsal root ganglia in sensory pathways?

They contain the cell bodies of sensory neurons that transmit information to the spinal cord.

What are the two main divisions of the Autonomic Nervous System (ANS)?

Sympathetic and Parasympathetic divisions.

What is the primary function of the Sympathetic division?

To prepare the body for 'Fight-or-Flight' responses during stressful situations.

What is the primary function of the Parasympathetic division?

To maintain routine functions and promote 'Rest and Digest' activities.

What type of neurons are involved in the autonomic nervous system?

Presynaptic and postsynaptic neurons.

Where do the presynaptic neurons of the Parasympathetic division originate?

From the brain stem or sacral spinal cord segments (Craniosacral division).

Where do the presynaptic neurons of the Sympathetic division originate?

From thoracic and lumbar spinal cord segments (Thoracolumbar division).

What is the typical length of presynaptic neurons in the Parasympathetic division?

Long presynaptic neurons and short postsynaptic neurons.

What is the typical length of presynaptic neurons in the Sympathetic division?

Short presynaptic neurons and long postsynaptic neurons.

Which cranial nerve is responsible for pupil constriction in the Parasympathetic division?

Oculomotor nerve (CN III).

What is the effect of the Parasympathetic division on the heart?

It decreases heart rate.

What is the effect of the Sympathetic division on the heart?

It increases heart rate.

Which cranial nerve stimulates the lacrimal gland for tear production?

Facial nerve (CN VII).

What is the role of the Vagus nerve (CN X) in the Parasympathetic division?

It innervates the lungs, heart, and GI tract, promoting decreased heart rate and increased digestive activity.

What is the sympathetic trunk?

A nerve chain with ganglia where presynaptic sympathetic neurons synapse with postsynaptic neurons.

How do sympathetic neurons reach the body wall?

Presynaptic neurons enter the sympathetic trunk, synapse in a chain ganglion, and then rejoin the spinal nerve.

What is the pathway for sympathetic innervation to visceral organs?

Presynaptic neurons enter the sympathetic trunk, join the splanchnic nerve, synapse at collateral ganglia, and travel to targets.

What is the fight or flight response?

A physiological reaction initiated by the sympathetic division in response to perceived threats.

What neurotransmitters are released by the adrenal medulla during the fight or flight response?

Epinephrine (adrenaline) and norepinephrine.

What is the effect of sympathetic stimulation on the pupils?

It dilates the pupils.

What is the effect of sympathetic stimulation on the lungs?

It dilates bronchioles to increase airflow.

Which cranial nerve is responsible for salivation in the submandibular and sublingual glands?

Facial nerve (CN VII).

What is the role of the Glossopharyngeal nerve (CN IX) in the autonomic nervous system?

It stimulates the parotid salivary gland to produce saliva.

What is the role of the sympathetic chain in the autonomic nervous system?

It allows sympathetic neurons to travel up and down beyond the thoracolumbar region.

What is the difference between somatic and autonomic motor pathways?

Somatic pathways innervate skeletal muscle, while autonomic pathways innervate cardiac muscle, smooth muscle, and glands.

What are the targets of the sympathetic division?

Heart, lungs, blood vessels, sweat glands, and visceral organs.