Lecture 1 T1 CNS Flashcards by Amelia Mellor

What is a nucleus?

aggregation of dendrites and nerve cell bodies in the CNS

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What is a ganglion?

aggregation of dendrites and nerve cell bodies in the PNS

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What is a nerve?

bundle of fibers (axons) in the PNS

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What is a tract?

Bundle of fibers (axons) in the CNS

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What is a commissure?

Tract in the CNS that crosses from one side to the other

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What is white matter?

Areas of myelinated axons

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What is gray matter?

Areas of unmyelinated axons, cell bodies, and dendrites

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What part of the tripartite brain in the telencephalon?

proencephalon

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What are the lumina of the telencephalon?

Lateral ventricles

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What are the parts of the floor of the telencephalon?

Basal nuclei, olfactory lobes and nerves (subconscious motor control and muscle tone).

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What makes up the roof of the telencephalon?

cerebral cortex

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What is the lumen of the diencephalon?

third ventricle

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What makes up the roof of the diencephalon?

epithalamus

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What makes up the walls of the diencephalon?

thalamus (the relay station)

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What makes up the floor of the diencephalon?

Hypothalamus and infundibulum

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What is the function of the epithalamus?

involved in emotional and visceral responses to odors. pineal body.

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What is the function of the thalamus?

Major relay center for afferent and efferent info to and from cerebrum and other areas of the brain.

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What is the function of the hypothalamus?

Mammillary bodies (nuclei) involved in olfactory reflexes and emotion responses to odors. supraoptic and paraventricular nuclei.

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Name the functions of the diencephalon?

controls and integrates ANS
Associated with many kinds of visceral activity
intermediary btwn nervous and endocrine systems
controls normal body temp
maintains extracellular fluid volume
biorhythm oscillator

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What make sup the lumen of the mesencephalon?

cerebral aqueduct of sylvius

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What makes up the roof of the mesencephalon?

tectum.

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What is the tectum made up of?

superior colliculi (visual reflexes) and inferior colliculi (auditory and olfactory reflexes).

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What makes up the floor of the mesencephalon?

Tegmentum

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What cranial nerve nuclei are located in the mesencephalon?

CN III - IV

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What makes up the floor of the mesencephalon?

Tegmentum

What cranial nerve nuclei are located in the mesencephalon?

CN III - IV

What makes up the lumen of the metencephalon?

part of the fourth ventricle

What makes up the roof of the metencephalon?

cerebellum

What makes up the floor of the metencephalon?

Pons, which is the relay station between the cerebrum and cerebellum and controls sleep and respiratory centers.

What structure has a cortex and is connected to other parts of the brain via large pairs of fiber tracts called peduncles?

cerebellum

What are the functions of the cerebellum?

- coordinates skeletal muscle movements - maintain equilibrium and posture - synergic control of muscle activity

What makes up the lumen of the myelencephalon?

part of the fourth ventricle

Tell me about the posterior choroid plexus.

Highly vascularized, CSF

What makes up the roof of the myelencephalon?

posterior choroid plexus

Tell me about the posterior choroid plexus.

Highly vascularized, CSF

What are the vital reflex centers of the myelencephalon?

Cardiac center, vasomotor center, centers related to respiration.

What is the cell body?

Part of the neuron that encloses the nucleus and other organelle necessary to maintain and repair the neuron.

What are dendrites?

Branches off the cell body that carry information to the cell body.

What are characteristics of dendrites?

- usually several to many dendrites per neuron - relatively short, especially compared to the axon - often branched - HAVE RECEPTORS FOR NEUROTRANSMITTERS - CONDUCT LOCAL POTENTIALS

In humans, can neurons replicate and divide?

No, but they can repair themselves.

What is the axon?

The part of the neuron that carries information to another neuron or muscle cell.

What are characteristics of a neuron?

- usually relatively long - single axon per neuron - CONDUCTS ACTION POTENTIAL/NERVE IMPULSE - RELEASES NEUROTRANSMITTER - axon ends in short branched processes called telodendria. - may also have collateral branches

What are characteristics of telodendria?

They give off endings called terminal boutons, and the terminal boutons contain synaptic vesicles filled with neurotransmitters.

What is the name of the cell membrane of the axon?

axolemma

What is the name of the cytoplasm is the axon?

axoplasm

T/F: the axon contains mitochondria, neurofilaments, and neurotubules.

true

The axon is covered by a neurolemma which is made up of what? is it unmyelinated or myelinated?

Schwann cells, often myelinated

What is the only part of the neuron that is myelinated?

axon

Are all axons myelinated?

In the CNS, what is the name for the myelinating cells?

oligodendrocytes

The white ramus communicans carries what?

myelinated preganglionic fibers

The gray ramus communicans caries what?

unmyelinated postganglionic fibers back to spinal nerve

Where is the site of the cell bodies of postganglionic sympathetic nerves?

paravertebral ganglia

Where is the site of synapses between preganglionic myelinated sympathetic neurons and postganglionic non-myelinated sympathetic neurons

paravertebral ganglia

What is the name of the nerve that supplies the viscera?

Splanchnic nerve

Where is the site of synapses between preganglionic myelinated sympathetic neurons and postganglionic non-myelinated neurons

prevertebral ganglion

What is a reflex arc?

A pathway that leaves from and returns to the CNS. It consists minimally of a sensory pathway and a motor pathway.

What is the function of the afferent pathway in the reflex arc?

carry sensation from non-visceral structures such as the skin and skeletal muscle.

What is the function of the efferent pathway in the reflex arc?

carry motor signals to skeletal muscles.

What is the function of association neurons/interneurons?

Modulate the interaction between the afferent and the efferent neurons

What component of the synapse includes vesicles filled with neurotransmitters?

presynaptic membrane

What component of the synapse include receptors or neurotransmitters?

postsynaptic membrane

What is a monosynaptic pathway?

These are pathways consisting only of afferent neurons and efferent neurons. Each pathway has only a single synapse.

What is a polysynaptic pathway?

This is a pathway consisting of interneurons as well as afferent and efferent neurons; each pathway has multiple synapses.

What state is a cell body in when it is at -65 mV?

Resting

What state is a cell body in when it is at -45 mV, typically due to an influx of sodium?

Excited

What state is a cell body in when it is at -70 mV, typically due to an influx of chloride ion or efflux of potassium ion.

Inhibited

What is a somatosensory axis?

refers to the sequence of structures involved in the transmission of a sensory signal from the peripheral receptors to higher brain centers

What are the components of the somatosensory axis?

peripheral receptors - afferent neurons - spinal cord or brainstem - reticular substance - cerebellum - thalamus - somesthetic areas of cerebral cortex

Afferent somatosensory neurons are arranged in a series of three, what are their names?

Primary, Secondary, and Tertiary

What is the function of the primary afferent neurons in the somatosensory axis?

synapse in the posterior horns of the spinal cord or sensory nuclei in the brain.

What is the function of the secondary afferent neurons in the somatosensory axis?

synapse in the thalamus

What is the function of the tertiary afferent neurons in the somatosensory axis?

synapse in the somesthetic areas of the cerebral cortex

What is the skeletal motor nerve axis?

the sequence of structures involved in the transmission of an action potential from the higher brain centers to skeletal muscles.

What does the skeletal motor nerve axis consist of?

Motor cortex of cerebrum, efferent pathways (upper motor neurons extending from cortical areas to the anterior horns of the spinal cord and alpha motor neurons extending to the skeletal muscles), and effectors.