CNS exam 1

Coordination, association, and integration

What are the three dominant roles of the nervous system?

Twelve Cranial nerve pairs (24 total)

How man cranial nerves are there?

31 spinal nerve pairs (62 total)

How man spinal nerves are there?

Brain and Spinal Cord

The central nervous system consists of what?

Cranial nerves III, VII, IX, and X and Sacral nerves 2, 3, and 4

What nerves are involved in the parasympathetic division, known as the "craniosacral" subdivision?

Short

Are post-ganglionic axons in the parasympathetic division long or short?

Spinal nerves from T1-L2 level

What nerves are involved in the sympathetic nervous system, known as the "thoracolumbar" subdivision?

Norepinephrine

The sympathetic nervous system is said to be "adrenergic", which means it releases what neurotransmitter?

Sweat glands and arrector pili muscles

What are the exceptions to the adrenergic rule of the sympathetic nervous system?

1:17

What is the ratio of preganglionic to postganglionic neurons in the sympathetic nervous system?

1:2

What is the ratio of preganglionic neurons to post ganglionic neurons in the parasympathetic nervous system?

Ectoderm

What germ layer does the central nervous system come from?

Prosencephalon, Mesencephalon, Rhombencephalon

What are the three primary brain vesicles?

Telencephalon and Diencephalon (Te-Di is a Pro)

What are the two divisions of the prosencephalon?

Metencephalon and Myelencephalon (Rhom Met Mye)

What are the divisions of the Rhombencephalon?

First vestige of the nervous system

What is significant about the neural plate?

Spinal Cord

What does the neural tube form into?

Peripheral Nervous System (PNS)

What does the neural crest form into?

Cerebral cortex, basal ganglia, lateral ventricles

What are the mature structures of the telencephalon?

Thalamus, hypothalamus, pineal gland, 3rd ventricle

What are the mature structures of the diencephalon?

Corpora quadrigemina, cerebral peduncles, cerebral aqueduct

What are the mature structures of the mesencephalon?

Cerebellum, Pons, 4th ventricle

What are the mature structures of the Metencephalon?

Medulla oblangata, 4th ventricle

What are the mature structures of the myelencephalon?

10% of body weight, uses 60% of the oxygen of the body

What percentages of total body weight and consumption of oxygen is the brain at birth?

2-2.5% of body weight, uses 20% of the oxygen of the body

What percentages of total body weight and consumption of oxygen is the adult brain?

Neuroblasts, ependymal cells, and glioblasts

What three cells do neuroepithelial cells give rise to?

Astrocytes and oligodendrocytes

What does the glioblast divide into?

Yes

Can glioblasts undergo mitosis?

5-10x as many

How many glioblasts (and their derivatives) are there compared to neurons?

Astrocytes

What are the most numerous cell in the adult central nervous system?

Protoplasmic astrocytes

What type of astrocyte is found in gray matter?

Fibrous astrocyte

What type of astrocyte is found in white matter?

Astrocytes

What are necessary for the function of the blood brain barrier? (BBB)

Astrocytes

What cell forms scar like tissue in CNS injuries?

Glutamate, dopamine, and serotonin

What neurotransmitters may be directly affected by astrocytes?

Perineuronal oligodendrocytes

What type of oligodendrocyte is found in the gray matter?

Interfasicular Oligodendrocytes

What type of oligodendrocyte is found in the white matter?

Interfasicular Oligodendrocyte

What forms the myelin covering in CNS neurons

Ependymal Cells

What cells line the central canal and the ventricles of the CNS?

Ependymal cells

What cells secrete CSF and form coroid plexus?

Tanycytes

Ependymal cells have specialized cells in the 3rd ventricle that transport CSF from the 3rd ventricle to the hypophyseal portal system. What are these cells called?

Astrocytoma

What is the most common type of tumor regarding glial cells?

Gliobastoma

What is the most lethal tumor regarding glial tumors?

Ependymoma

What type of glial tumor is said to be "restrictive"?

Mesoderm

Where does the microglia derive from?

Microglia

What cell has a phagocytic function, which involves clearing dead tissue?

Microglia

What cell mediate immune responses in the CNS?

Radiation and alcohol

Exposure to what may cause over/undershooting of designated targets during critical embryonic stages?

Unipolar

What type of neuron is found in sensory neurons or ganglia?

Bipolar

What type of neuron is found in special sensory pathways (taste, smell, sight, hearing)

Multipolar

What is the most abundant type of neuron?

Long

Do golgi type I neurons have long or short axons?

Short

Do golgi type II neurons have long or short axons?

Golgi Type II

What is the most common type of multipolar neuron?

Internuncial

If a neuron is entirely within the CNS it is said to be what type of neuron?

Commissural

What type of internuncial neuron connects equivalent structures of the CNS?

Ipsilateral projection

What type of internuncial neuron starts at one structure and ends at another structure, but on the same side of the midline?

Contralateral Projection

What type of internuncial neuron starts at one structure and ends at another structure on opposite sides of the midline?

Intrasegmental

What type of internuncial neuron starts at one cord level and ends at the same cord level?

Intersegmental

What type of internuncial neuron starts at one cord level and ends at a different cord level?

Neuropodia

What part of the neuron is the neurotransmitter released?

Telodendria

What part of the neuron is the term for axon terminals?

Axon Hillock

Where is the action potential initiated in a neuron?

Axodendritic

What type of synapse is most common in the CNS?

Nissl Bodies

What are clumps of rough E.R. in the CNS?

Tigroid bodies

What is another name for nissl bodies?

Axon or axon hillock

Where do nissl bodies not appear?

Retrispersion of the golgi apparatus

What is chromatolysis of the nissl bodies often confused with?

20-30 nm in diameter

How big are microtubules?

3-5 nm in diameter

How big are microfilaments?

9-10nm in diameter

How big are neurofilaments?

Slow transport

What type of transport doesn't require energy, but moves large molecules like protein?

Anterograde

What direction(s) can slow transport move?

Fast transport

What type of transport requires energy and moves small items like lysosomes and enzymes?

Anterograde or retrograde

What direction(s) can fast transport move?

Unmyelinated

Will a fiber less than one micron in diameter be myelinated or unmyelinated?

Sometimes myelinated

What happens if a fiber is 1-2 microns in diameter?

Always myelinated

Will a fiber greater than 2 microns be myelinated?

Fiber diameter and myelination

What two things determine conduction velocity?

Yes

Will every fiber in the PNS have a schwann cell covering?

No

Will every fiber in the PNS be myelinated? (Remember the diameter rule)

Node of Ranvier

What is the small space between schwann cells?

Endoneurium

What layer of connective tissue on a nerve is highly vascular, but covers the smallest portions of the nerve?

Perineurium

What layer of connective tissue on a nerve is fairly elastic and is continuous with the pia mater?

Epineurium

What is the outer layer of CT that covers a nerve, is very inelastic, and is continuous with the dura mater?

Interfasicular Oligodendrocytes

What cell myelinates fibers of the CNS?

Schwann Cells

What cell myelinates fibers of the PNS?

Up to 40

How many fibers can an oligodendrocyte cover?

Usually one

How many fibers can a schwann cell cover?

Interfasicular oligodendrocytes

What structure does multiple sclerosis attack?

Schwann Cells

What structure does Guillan Barre syndrome attack?

Acetylcholine (ACh)

What was the first neurotransmitter identified?

GABA

What is the most widespread INHIBITORY neurochemical?

Glutamate

What is the most abundant neurochemical? It is usually excitatory.

Endosteal (highly vascular) and meningeal (fibrous layer)

What are the layers of the dura mater?

Endosteal layer

What layer of the dura mater is lost in the vertebral canal?

Yes, areolar and adipose tissue, along with the internal vertebral venous plexus

Is there an epidural space in the vertebral column? If so, what is it filled with?

Meningovertebral ligaments

What is is called where the dura slips and attaches to ligaments of the periosteum of the vertebrae?

Dural Falces

What are double layers of meningeal dura that extend into fissures of the brain?

Falx Cerebri

What falx is located in the longitudinal cerebral fissure?