Ch. 2 - Neuroanatomy

Planes

sagittal: divides right and left

horizontal: cuts across at right angles

coronal: divides anterior and posterior

White Matter conveys info and is composed of

• axons

  • convey info from cells

• myelin

  • insulating covering

  • fatty white substance

A bundle of axons may also be referred to as

• tract

• leminiscus

• column

• peduncle

• capsule

Gray matter integrates info and is composed of mostly

• neuron cell bodies

  • basically the control room

Ganglia

groups of cell bodies in PNS

Nuclei

groups of cell bodies in CNS

The cortex is ___ matter

gray

The spinal cord goes from the ____, to _____, ending in ____

foramen magnum, L1, conus medullaris

The spinal cord has __ segments

31

Each spinal cord segments have a pair of ___ ___

spinal nerves

A spinal nerve is formed by the junction of ___ and ____

• dorsal root

  • enlarges to a dorsal root ganglion at the end and contains cell bodies

• ventral root

  • has its cell bodies in the spinal cord

• *these roots allow the spinal nerve to connect to the spinal cord

Dorsal, lateral, and ventral horns are made up of ___ matter

gray

These horns contain

cell bodies of motor neurons, interneurons, and ending of sensory neurons

Dorsal, lateral, and ventral columns are made up of ___ matter

white

Functions of the brain stem

• conveys info between cerebrum and spinal cord

• integrates info

• controls equilibrium

• regulates vital functions

Medulla

• is continuous with spinal cord

• ant. surface includes

  • olive, pyramids (axons), pyramidal decussation (where axons cross)

What CN attach at the medulla?

IX - Glossopharyngeal

X - Vagus

XI - Accessory

XII - Hypoglossal

Function of the medulla

contains vital centers and most sensory and motor paths cross here

Pons

• sits above the medulla

• contains fiber tracts

What CN attach at the pons?

V - Trigeminal

VI - Abducens

VII - Facial

VIII - Vestibulocohlear

Midbrain Function

contains centers for arousal and wakefulness

What CN come from midbrain?

III - Oculomotor

IV - Trochlear

Anteriorly, the midbrain has

2 cerebral peduncles that are fibers coming from the cerebral cortex

Dorsally, the midbrain has the

tectum which has

• 2 superior colliculi

• 2 inferior colliculi

*essential for auditory and visual orientation

What 3 CN are purely sensory?

I - Olfactory

II - Optic

VIII - Vestibulocochlear

Cerebellum is connected to the posterior brain stem by

fiber tracts (superior, middle, and inferior peduncles)

Cerebellum has _ large cerebellar hemispheres that are composed of the

2

cerebellar cortex, white matter, and deep nuclei

The cerebellar hemispheres are separated by

vernis

Function of Cerebellum

• control balance and equilibrium

• coordinate movement

• some motor learning

Cerebrum

• largest part of the CNS

• consists of the cerebral hemispheres and the diencephalon

Diencephalon contains

hypothalamus, thalamus, and epithalamus

Thalamus location

• nuclei in center that relays info to cortex

Thalamus function

• integrate sensations

• process some emotions and memory

• regulate consciousness, arousal, and attention

Hypothalamus function

• maintains body temp, metabolic rate, chem of tissues and fluids

• regulates eating, reproduction, defensive behaviors, and expression of emotions

Epithalamus is also known as the

pineal gland

Subthalamus

influence on movement

Cerebral hemispheres are divided by

longitudinal fissure

Gyri (gyrus)

elevations of cerebral hemispheres

Sulci (sulcus)

grooves of cerebral hemispheres

Functions of Cerebral Hemispheres

• processes sensory, motor and memory info, reasoning, language, nonverbal communication, intelligence, and personality

Internal Capsule

• contains axons projecting back and forth between cerebral cortex and subcortical structures

Central Sulcus

separates frontal and parietal lobe

Parieto-occipital Sulcus

separates parietal and occipital lobe

Lateral Sulcus

superior to temporal lobe

Cingulate sulcus

binds limbic lobe

Frontal lobe

• initiates movement

• judgement

• foresight

• mood

• affect

Parietal lobe

• sensory input

• spatial relationships

• object detail

• abstract intelligence

Temporal lobe

• auditory functions

• learning and memory

• connections with limbic system

Occipital lobe

• visual functions

Limbic System

• emotion

• motivation

• instinct

• visceral processes (digestion)

• x and social relationships

• attention

• memory

Insular

• produces nausea

• bp and hr changes when stimulated

Basal Ganglia Nuclei

• areas of gray matter that are embedded in the white matter of the cerebral hemispheres

The limbic system is located in

diencephalon and cerebral hemispheres

The structures associated with the limbic system are

• thalamus

• hypothalamus

• cerebral cortex

• several deep nuclei

• hippocampus

Lesions

are an area of damage or dysfunction

Focal Lesion

• limited to a single location

  • ex. tumor in SC

Multifocal Lesion

• several, non symmetrical locations

  • ex. metastasized tumor

Diffuse affect bilaterally symmetrical structures w/o crossing midline as a single tumor

ex. Alzheimers

Acute

• minutes or hours to maximal symptoms

• indicative of a vascular problem

Subacute

• takes a few days to reach maximal symptoms

• indicative of an inflammatory process

Chronic

• gradual worsening of signs for weeks or years

• indicative of a tumor or degenerative disease