Neuroanatomy and Gross Structure of the Human Nervous System

Function & organizational principles of the brain

1. interconnectivity in the brain

2. centrality of the central nervous system

2a. hierarchy of neuroaxial organization

3. Laterality of brain organization

4. structural and functional specilization

5. topographical organization in cortical pathways

6. brain plasticity

7. nonmythical brain

Brain interconnectivity

Constant interactivity for information integration through association fibers, commissural fibers, and projection fibers.

association fibers

connect different parts of the same hemisphere

commissural fibers

connect one hemisphere to the other

projection fibers

connect the hemispheres with lower brain or spinal cord

centrality of CNS

CNS as the Decision Maker for:

Integration of incoming/outgoing information

Analyzes and synthesizes a variety of information

Generation of appropriate response

CNS

central nervous system

CNS contains

brain and spinal cord

PNS

peripheral nervous system

PNS contains

cranial and spinal nerves

incoming

sensory

outgoing

motor

Hierarchic organization

each level reflecting organizational complexity (complexity increases with ascending levels)

lowest level: simpliest level

highest level: more complex

lowest level

spinal cord reflexes

highest level

Cerebral cortex- sensory motor integration and higher mental functions

laterality organization

-bilateral anatomic symmetry

-unilateral functional differences

-contralateral sensorimotor control

Bilateral Anatomic Symmetry

The two sides of the brain look alike. Same basic structure.

unilateral functional differences

- Left hemispheric dominance for language

- Right hemispheric dominance for emotions, visual spatial skills, musical skills, paralinguistic functions, and attention

Contralateral Sensorimotor control

The right cerebral cortex controls and feels the left body. The left cerebral cortex controls and feels the right body

Functional Networking

Networking

Distinct parallel pathways conducting different types of information

Sensory fibers

Touch

Discriminative touch

Motor efferents

Pathways to various limbs

topographical organization

-Selectivity of Organization

*Spatial organization of neurons, tracts, and terminals serving the same function

*Discrete representation of body surfaces and muscles in the brain

*Discrete pathway passage

*Somatosensory homunculus: each part of your body is represent in the brain

Plasticity in the brain

- Reorganizational Capacity

- Implications for learning and recovery

Plasticity

the ability to change or org as a result of experience and ability to reorganize or modify tissue function when injured

Reorganizational Capacity

- Brain's ability to reorganize & modify tissue functions when faced with pathology

- Adaptation to internal/external changes

Implications for learning and recovery

- Greater plasticity at a young age: learn and adapt, brain is spongy

- Importance of critical period for experience

- Tissue-function reorganization with CVA

CVA

cerebrovascular accident (stroke)

The mature brain is ____

age 25

Nonmythical Brain

-Brain potential-independent of gender, color, or cultural variations

-Notable variations in brain size, shape, or weight

-Functionally unimportant normal variations

brain orientation: cerebrum

Rostral, caudal, dorsal and ventral

rostral

near front of the head

caudal

back of brain or head

dorsal

top of brain

Ventral

bottom of brain

plans of brain section

sagittal, midsagittal, coronal, horizontal

Sagitall

divides body into left and right

Midsagittal

the plane dividing the body into equal right and left halves

coronal

divides the body into slices from front to back

horizontal

divides into top and bottom

lateral

more to outside

medial

more middle, inside

Proximal

close

distal

far

gyrus (gyri)

convolution or the hill

sulcus (sucli)

fissure or the valley

Commissure

band of fiber together

gray matter

nerve cells that are not myelinated, not extra coating

white matter

nerve cells that are myelinated, they are wrapped

neuron

basic building block of the brain; transmits info

glial cell

cells that provide support, don't process info; it goes to damage areas to fill in ex: cheerleader

PNS (peripheral nervous system)

Ganglion and nerve; AMS: anamonic nervous system

ganglion

collection of neurons ex: ganglion cyst

ganglion of the dorsal root

The ______ _____ __________ is located in the intervertebral foramen.

nerve

bundle of axons ex: facial nerve

facial nerve is what number

VII

CNS (central nervous system)

Nucleus, tract and fascicules

nucleus

mass of neurons

caudate nucleus

mass of neurons in basal ganglia

tract

bundle of axons in the CNS

corticospinal tract

connections between brain and spine, motor traveling down

fascisulus

several parallel running tracts, bundle of axons traveling to same place

The CNS consists of the

brain and spinal cord

Brain consists of

cerebrum, cerebellum, brain stem

Brainstem consists of

midbrain, pons, medulla oblongata

spinal cord

reflexing controlling center; connects brain to peripheral structures

Primary Brain Divisions

prosencephalon, mesencephalon, rhombencephalon

Prosencephalon (forebrain)

telencephalon and diencephalon

telencephalon

cerebral hemispheres, basal ganglion and limic lobe

Diencephalon

thalamus and hypothalamus

Rhombencephalon (hindbrain)

metencephalon and myelencephalon

Metencephalon

pons and cerebellum

Myelencephalon

medulla oblongata

Cerebrum

two hemispheres: cerebral cortex and basal ganglia

cerebral cortex

gray matter: nerve cells are arranges in six layers

serves all symbolic functions-language, orientation, memory and attention

basal ganglia

masses of gray matter in depth of each hemisphere

important for regulating motor functions and muscle tone

Diencephalon: central core of the brain

thalamus and hypothalamus

thalamus

collection of subcortical nuclei, sensory relay station: coming in from the body to brain and then to thalamus

Hypothalamus

central structure for control of various metabolic activities

body temperature, water balance and sugar

Midbrain

links brain with brainstem, tiny and critical

- CN nuclei

Pons

regulates facial movement and sensation

-respiration

- CN nuclei

medulla oblongata

Part of the brainstem that controls vital life-sustaining functions such as heartbeat, breathing, blood pressure, and digestion.

- CN Nuclei

cerebellum

dorsal-caudal to the brain

regulates skilled movement

contributes to maintenance of equilibrium and coordination of motor activity

attached to but not part of the brainstem