Exam 1

What are the components of the CNS?

\-Brain

\-Spinal Cord

What makes up the PNS?

\-Cranial and spinal nerves and their associated ganglia

\-Ventral horns of the spinal cord

\-Fiber bundles have names of nerve, nerve root, nerve trunk, nerve cord and ramus

What is the gray matter composed of?

\-Neurons (cell bodies)

→Also called ganglia or nuclei

What is the white matter composed of?

\-Composed of fiber tracts (axons/nerve fibers)

\- +/- wrapped in myelin sheath (fat)

\-Make up fiber bundles in CNS

What do the fiber bundles in the CNS contain?

\-Groups of axons with common origin and common destination

→Tract

\-Common names for tracts that are used interchangeably

→Fasciculus, Brachium (arm in Greek), Peduncle, Column or Lemniscus

What are the spinal cord and the rootlets of the alpha motor neurons wrapped in?

Pia mater

As these rootlets exit the spinal cord, what do they become wrapped in?

\-Arachnoid mater

\-Dura mater

What are the major divisions of the brain?

\-Hindbrain

\-Midbrain

\-Forebrain

What is the hindbrain?

\-Medulla

\-Pons

\-Cerebellum

What is the midbrain?

Connects the hindbrain to the forebrain

What is the forebrain?

\-Cerebrum

\-Diencephalon

What is the cerebral cortex?

Outer gray matter of cerebrum that contains nerve cell bodies

What is cerebral cortex composed of?

\-Gyri, sulci (fissures)

\-Two major grooves on the lateral surface of the brain

→Lateral Sulcus (Sylvian fissure)

→Central Sulcus (Rolandic or Sulcus of Rolando)

\-Cortical thickness varies among areas of the cerebrum

→Number of nerve cell layers

What are the 6 lobes of the brain?

\-Frontal

\-Occipital

\-Parietal

\-Temporal

\-Limbic

\-Insular

Does the central sulcus go all the way to the temporal lobe?

No

The corpus callosum is made up of what?

White matter

Directional Terms for the Brain

\-Superior/Dorsal

\-Anterior/Rostral

\-Posterior/Caudal

\-Inferior/Ventral

What are the types of neurons?

\-Unipolar

\-Bipolar

\-Multipolar

What is a unipolar neuron?

\-A cell body with a single neurite

\-Divides into peripheral and central processes

\-Found in dorsal root ganglion

What is a bipolar neuron?

\-One axon

\-One dendrite

What is a multipolar neuron?

\-Many neurites from cell body

→Most are dendrites

\-Found in brain and spinal cord

What are the two types of synapses?

\-Electrical

\-Chemical

What is an electrical synapse?

\-Bridges (tight junctions) connect one synapse to another

\-Ionic current

→Very fast, Little delay

\-20 nanometer synapse

What is a chemical synapse?

\-Consist of presynaptic and postsynaptic neurons that are completely separated by synaptic cleft

\-Synaptic vesicles in presynaptic terminal contain neurotransmitters

What are ligand-gated receptors?

\-Modulate neurotransmitters effect

→Increase or decrease depending on state of postsynaptic neuron

What is chemical conduction?

\-Occurs in one direction only

\-Transmission can be excitatory or inhibitory

\-Depolarization is a summation of activity at thousands of receptors

What are the main elements of a synapse?

\-Presynaptic terminal

\-Presynaptic receptors

\-Synaptic cleft

\-Postsynaptic receptors on postsynaptic terminal

What is capacitance?

The ability to store charges on opposite sides of 2 opposing surfaces

Is a NT intrinsically excitatory or inhibitory?

\-No

→Its effect at any given synapse is determined by the nature of the receptor to which it binds

What ion do voltage-dependent channels at the presynaptic axon terminal depend on?

Calcium

IF stimulation of one presynaptic neuron evokes an excitatory response in one postsynaptic neuron, what occurs?

Excitatory postsynaptic potential (EPSP)

IF stimulation of one presynaptic neuron evokes an inhibitory response in one postsynaptic neuron, what occurs?

Inhibitory postsynaptic potential (IPSP)

The impact of any individual synapse depends on what?

\-Amount of transmitter released

\-Number of postsynaptic receptors present

\-Distance from trigger zone

\-History of activity at that synapse

What are ionotropic receptors?

\-Ligand-gated channel

\-Leads to a change in the channel and an ion flux

\-Really fast

What is a metabotropic receptor?

\-G-protein-coupled receptors

\-A neurotransmitter needs his buddy

\-Travels a little slower

\-Neuromodulators

What is the most common neurotransmitter?

Acetylcholine

With a lumbar disc herniation, what can be lost/decreased?

\-Deep tendon reflexes

\-Bladder control

What is an epidural hemorrhage?

\-Blood between skull and dura mater

\-Mainly due to arterial bleed

\-Life threatening emergency

What is a subdural hemorrhage?

\-Bleeding between the dura and layers of meninges (below the dura and above the brain).

\-Mainly venous

\-Can be acute or chronic

Where is the subarachnoid space located?

\-Between arachnoid mater and pia mater

\-Aneurysms occur here

What is included in the paracentral lobule?

\-Precentral gyrus

\-Postcentral gyrus

What are the four parts of the corpus callosum?

\-Rostrum

\-Genu

\-Body

\-Splenium

What is the function of the corpus callosum?

\-Connects the two hemispheres of the brain and allows the hemispheres to communicate with each other

\-Made up of white matter

→Axons that allow crossing from one side to the other

What is the internal capsule?

\-It consists of ascending and descending tracts (motor and sensory) that connect the thalamus and the cerebral cortex

\-Allows information to go from the spinal cord to the cerebrum and vice versa

What are the parts of the internal capsule?

\-Anterior limb

\-Genu

\-Posterior limb

\-Retrolenticular division

\-Sublenticular division

What are corticofugal tracts?

\-Motor tracts

→We specifically need to know the corticospinal tract

What is the corticospinal tract?

\-A descending somatic motor tract

\-White matter

\-Efferent fibers converge and make a path through the internal capsule and brainstem to get to the spinal cord

\-Afferent fibers make a separate path upward to reach the cerebral cortex from the spinal cord

What is the corticobulbar tract?

\-Controls all voluntary movement for speech production. -Descends from motor cortex through internal capsule but terminates at cranial nerves.

If you have a tumor in the thalamus that grows laterally, what will be affected?

\-Loss of sensation on opposite side

→Superior thalamic radiation

\-If it travels even more lateral

→Motor deficits (paralysis, corticospinal tract)

If you have a tumor in the thalamus that grows superiolaterally, what will be affected?

\-Facial paralysis

→Affects corticobulbar tract

Lesions of the internal capsule are usually due to what?

Hemorrhaging/bleeding

What s/s are produced if you have a lesion that affects the genu and posterior limb?

\-Lower ½ of opposite face weakness (Genu)

\-Contralateral hemianesthesia (Somatosensory radiation)

\-Contralateral spastic hemiplegia (Corticospinal tract)

\-Optic radiations

\-Auditory radiations

What do neurons do?

\-Generate & transmit the nerve impulse

\-Cell body is necessary for metabolism

\-Receives sensory input from external sources

What is conduction?

\-Speed and strength of a signal being transmitted by nerve cells

\-Nodes of Ranvier speed this up

What is axoplasmic transport?

\-Neurotransmitters in nerve terminals

\-Reuptake mechanism

What types of cells are non-excitable and do not have axons?

Neuroglial cells

What is the purpose of the thalamus?

\-Act as relay center and directs impulses to cerebrum

\-Provides almost all the input to the cortex through thalamocortical projections

\-All sensory stuff has to go through here

Are all neurons in a column activated selectively by the same peripheral stimulus?

\-Yes

→EX: If your head itches, that stimulus will react with a motor response

Where are pyramidal cells found?

In the motor cortex

T/F Cell layers provide the depth of the cortex?

True

What areas surround the primary visual cortex and deal with the information specific to it?

\-Secondary visual cortex

\-Unimodal visual cortex

What are bidirectional connections with the limbic cortex?

\-Memory

\-Emotions

What connections allow for the performance of highest-order mental functions requiring integration of abstract sensory and motor info from appropriate parts of the nervous system, together with info from the limbic cortex?

Use of adjective “association” or heteromodal association cortex

What is the primary motor cortex?

Precentral gyrus

What is the primary visual cortex?

Occipital lobe

Axons from neurons in the precentral gyrus influence contralateral motor systems directly through what?

Corticospinal and Corticobulbar tracts

Axons from neurons in the precentral gyrus influence contralateral motor systems indirectly through what?

Their projections to the red nucleus and reticular formation

Axons project to and receive influences from what?

Recurrent loops through the cerebellum and the basal ganglia

Stimulation of specific parts of motor cortex results in what?

Isolated movements on the contralateral side of the body

M1 corresponds to the primary motor area and precentral gyrus, which stimulates what?

\-Stimulation of specific parts of this area

→Bilateral movements of:

\-→Extraocular muscles

\-→Muscles of the upper 1/2 of the face

\-→Muscles of the tongue

\-→Muscles of the mandible

\-→Muscles of the larynx

\-→Muscles of the pharynx

What is homunculus?

What does the premotor area do?

\-Receives inputs from sensory cortex, thalamus, and basal ganglia

\-Stores programs of motor activity as a result of past experiences

\-Programs activity for the primary motor area

\-Involved in controlling coarse postural movements through its connections with the basal ganglia

Which hemisphere is dominant for speech?

Left

Speech is the motor production of spoken words using what?

\-Larynx

\-Tongue

\-Face

Directional Terms for the Spinal Cord

\-Anterior/Ventral

\-Posterior/Dorsal

\-Superior/Rostral

\-Inferior/Caudal

In the brain where is the gray and white matter located?

\-Gray = outer

\-White = inner

What another term for bumps on the brain?

Gyri/ Gyrus

Whats another term for grooves of the brain?

Sulci

Where is the lateral fissure located?

Between the frontal and temporal lobes

What are other terms for the lateral fissure?

\-Lateral sucli

\-Sylvian fissure

Where is the central sulcus located?

Between the frontal and parietal lobe

What are other terms for the central sulcus?

\-Central fissure

\-Fissure of Rolando

\-Rolando fissure

The limbic lobe of the brain is associated with what?

\-Emotions

\-Homeostasis

The insular lobe of the brain is associated with what?

\-Emotions

→Pain

→Fear

→Sadness

→Happiness

The frontal lobe of the brain is known for what?

\-Memory

\-Problem solving

\-Motor function

The parietal lobe of the brain is known for what?

\-Sensory (but not vision)

→Temperature

→Touch

→Taste

\-Movement

The occipital lobe of the brain is known for what?

Vision

The temporal lobe of the brain is known for what?

\-Hearing

\-Language interpretation

What is the order of meninges from deep to superficial?

\-Pia mater

\-Arachnoid mater

\-Dura mater

T/F The spinal cord spans from caudal medulla oblangota to L1/2

TRUE

What structures anchor the spinal cord to the dura mater?

Denticulate ligaments

Know your myotomes

Do the dance!

In what location does the dorsal and ventral roots of the spinal cord join to form a spinal nerve?

Intervertebral foramina

In the spinal cord, what is the arrangement of gray and white matter?

\-White = outer

\-Gray = inner

How many pairs of Spinal Nerves are there?

31 pairs

The anterior horn of the spinal cord sends signals in which direction (To/Away) the CNS?

Away

The posteiror horn sends signals in which direction (To/Away) the CNS?

To

What matter is composed of neurons?

Gray

What matter is composed of fiber tracts?

White

What type of hemorrhage is commonly due to injury to menengial arteries and is considered a life threatening conditon?

Epidural space hemorrhage