The Spinal Cord, Reflexes, Autonomic System

Chapter 16 + 18

What is the dorsal longitudinal depression of the spinal cord?

posterior median sulcus

What is the ventral longitudinal depression of the spinal cord?

anterior median fissure

What is the tapering inferior end (official end) of the spinal cord?

conus medullaris

What projects out of the conus medullaris and is forms by a group of axons in the spinal cord?

cauda equina

What is the strand that is NOT nervous tissue, but dense irregular connective tissue, and is a thin strand of pia mater that travels in the cauda equina to the coccyx to help anchor the conus medullaris to the coccyx?

filum terminale

What is the difference between the brain and the spinal cord when it comes to meningeal space?

more true spaces in the spinal cord than in the brain

What space is between the dura mater and the periosteum of the inner walls of the vertebrae?

epidural space

What kind of tissue fills the epidural space?

areolar connective tissue, adipose connective tissue

What meninge fuses with the connective layers that surround the spinal nerves?

dura mater

What is potential space in the spinal cord?

subdural space

What is deep to the subdural space (dura mater)?

arachnoid mater

What true space is filled with cerebrospinal fluid?

subarachnoid space

What adheres directly to the spinal cord?

pia mater

What are the paired, lateral, triangular extensions that suspend and anchor the spinal cord to the dura mater?

denticulate ligaments

What horn houses somas of somatic motor neurons?

anterior horn

What horn contains somas of autonomic motor neurons (sympathetic), but only from T1-L2 in the spinal cord?

lateral horn

What horn contains axons of sensory neurons and interneurons?

posterior horn

What contains unmyelinated axons and connects the left and right sides of the spinal cord?

gray commissure

What is found in the gray commissure, is a continuation of the 4th ventricle in the brain, and contains cerebrospinal fluid?

central canal

What is found as interneurons of somatic and visceral sensory nuclei in the posterior horn?

sensory nuclei

What nuclei are found in the anterior horn?

somatic motor nuclei

What nuclei are found in the lateral horns (from T1-L2 only)?

autonomic motor nuceli

What are the rapid, automatic, involuntary reactions of muscles or glands?

reflexes

What is required to initiate the response of a reflex?

stimuli

What type of reflex occurs when the sensory axon synapses directly with the motor neuron? (Ex. stretch reflex)

monosynaptic reflex

What type of reflex occurs when the sensory axon synapses with one or more interneurons, which then synapses with the motor neuron? (Ex. withdrawal reflex)

polysynaptic reflex

What is the first component of a reflex?

receptor in the peripheral nervous system

What is the second component of a reflex?

receptor communicates with the central nervous system

What is the third component of a reflex?

an action occurs in a peripheral effector

Which motor nervous system uses one axon to travel from the spinal cord to a skeletal muscle fiber?

somatic nervous system

Which motor nervous system uses two axons to travel from the spinal cord to a smooth muscle, a cardiac muscle, or a gland?

autonomic nervous system

Where is the soma of the preganglionic neuron of the ANS found?

brain or spinal cord

From the soma of the preganglionic neuron of the ANS, what travels to the autonomic ganglia found in the peripheral nervous system?

preganglionic axon

What does the preganglionic axon of the ANS synapse with in the ganglia?

ganglionic neuron

What extends from the soma of the ganglionic neuron of the ANS to innervate a smooth muscle, cardiac muscle, or gland?

postganglionic axon

What division of the ANS is devoted to conservation of energy and replensihment of nutrient stores? (rest and digest)

parasympathetic

What division of the ANS is devoted to preparing the body for emergencies? (fight or flight)

sympathetic

What is the parasympathetic division of the ANS mostly concerned with?

homeostasis

What ganglia is close to the target?

terminal ganglia

What ganglia is found in the walls of the target?

intramural ganglia

What is the parasympathetic division also known as?

craniosacral division

What is the sympathetic division also known as?

thoracolumbar division

What is it called when all smooth muscle, cardiac muscle, and glands are stimulated by both the parasympathetic and sympathetic nervous systems?

dual innervation

What do both parasympathetic and sympathetic preganglionic axons release as the neurotransmitter that has an excitatory effect on the ganglionic neuron?

acetylcholine

What is the receptor for all ganglionic neurons?

nicotinic receptor

What exactly releases acetylcholine as the neurotransmitter?

preganglionic axons

What receptors do parasympathetic target cells have?

muscarinic receptors

What do sympathetic ganglionic axons that stimulate sweat glands and blood vessels in skeletal muscle release? And to what?

acetylcholine to muscarinic receptors

What do all other sympathetic ganglionic axons release? And to what?

norepinephrine to adrenergic receptors

What does the preganglionic axon of the SNS synapse in?

sympathetic trunk ganglia

What rami is a preganglionic axon of the SNS as it leaves the spinal nerve to enter to the ganglia?

white rami

What rami is a postganglionic axon of the SNS as it leaves to ganglia to return to the spinal nerve?

gray rami