Central Nervous System....

Central Nervous System:

Brain 

I). Ventricles

1). Several large ‘spaces’ filled with cerebrospinal fluid.
2). Cerebrospinal Fluid forms a liquid cushion in and around the brain and spinal cord that is constantly drained and replaced.

II). Cerebral Hemispheres

A). 2 Lobes
B). The cerebrum divides into:

i). frontal
ii). parietal
iii). temporal
iv). occipital
v). insula: forms part of the floor

C). The sections form regions

1). Basal nuclei

	regulating attention
	starting, stopping and monitoring movements.
	inhibits movements

2). Cerebral White Matter:

	communication between:
	Cerebral cortex and the lower CNS
	hemispheres

3). Cerebral Cortex
    a).  Superficial layer
    b).  mind

	awareness of self
	communication
	memory
	understanding

   c).  Convolutions

	gyri
	sulci
	fissures

    d).  Cerebral Dominance

1). Left side has greater control but not exclusive control over language, math, and logic.
2). Right side has greater control visual-spatial skills, intuition, emotion, and artistic skills.

    e).  Motor & Sensory control

	motor areas
	sensory areas
	association areas

concerned with sensory input of the opposite side of the body
2 hemispheres are not equal in function
No functional area acts alone.

i). Functional Area:  Motor areas:

Found: posterior part of the Frontal Lobe

	Include voluntary movements, repetitious movements, motor speech and voluntary eye movements.
	Operates left to right: .

ii). Sensory Areas:

Found in the parietal, temporal, & occipital lobes.

Conscious awareness of sensation.

Sensory areas: 1). Spatial discrimination: Parietal lobe—

skeletal muscles and skin and identifies region being stimulated.

2). Somatosensory association: Parietal lobe--

object being felt to produce an understanding.

3). Visuals Areas: Occipital Lobe—

Information from the eyes. Information from the right eye is mapped in the left visual cortex and vice versa.

Also interprets visual stimuli using past visual experience

4). Auditory Areas: Temporal Lobe---

Information on pitch, rhythm, and loudness in interpreted and perceived as sound.

Memories of sound are stored for reference.

5). Olfactory Cortex: Frontal Lobe & Temporal--

olfactory signals and perceives smells.

6). Gustatory Cortex: Parietal Lobe

Taste

7). Vestibular Cortex: Insula & Temporal Lobe

" Equilibrium" Position of the head in space.

iii). Association Areas

Communicates between the primary sensory areas and the motor areas and other areas to:

	analyze
	recognize
	act

on input in reference to past experience.
1.) All of the sensory areas are connected to specific association areas
2.). Prefrontal Cortex: Anterior Frontal Lobes

	Intellect, complex learning, recall and personality,
	abstract ideas, reasoning, concern for others

3). Language Areas: Temporal Lobe

Language dominant side:

Non-language dominant side:

4). General Interpretation Area: Found in one hemisphere only

integrates all signals into a single thought or understanding.

5). Visceral Association Area: Insula

Conscious perception of sensations from the internal organs. (ie. full bladder)

 
III). Diencephalon

A). Thalamus

	Gateway to the cerebral cortex
	Impulses from all of the senses converge at a specific receptor and are edited or synchronized before traveling to the cortex.
	functions in motor activities, cortical arousal, learning & memory.

B). Hypothalamus

	Located below thalamus.
	Main visceral control center. Functions in:

1). Autonomic control center  
2). Center for emotional response:
3). Body thermostat  
4). Regulation of food intake  
5). Regulation of water balance  
6). Regulation of circadian rhythm  
7). Controls endocrine system  

C). Epithalamus

1). Pineal gland
2). Choroid plexus

IV). Brain Stem

Rigid, preprogrammed, automatic behaviors for survival. (primitive behaviors)

A). Midbrain

Under the diencephalon forming the cerebral peduncles.
Functions in:
1). Visual reflexes 
2). Auditory relay  
3). Startle reflex 
4). Releases dopamine.
5). Limb flexion.

B). Pons

Transmits nerves from the medulla oblongata and the cerebrum, and from the cerebrum to the cerebellum, and the peripheral nerves to higher functions.

C). Medulla Oblongata (m.o.)

Functions to:
1). Sends ascending impulses through the brain stem and to higher functions 
2). Controls heart rate.
3). Vasomotor control that contract blood vessels.
4). Respiratory center regulates rate and depth of breathing.

V). Reticular Formation (r.f.)

Network that is scattered through the brain stem connecting the brainstem, cerebellum and cerebrum with ascending and descending tracts.
 When sensory information reaches the r.f., it activates or arouses the cerebral cortex.
Decrease r.f. results in sleep.

	It filters sensory information.
	Inhibits some reflexes.
	Coordinates muscle activity

VI).  Cerebellum

A).  Anatomy

	Located posterior and inferior to the cerebrum under the occipital lobe.
	overlapping sensory maps of the body.
	All the fibers in and out control the same side of the body. (ipsilateral)
	no direct connection to the cerebral cortex

B).  Functions:
C).  Needs to:

	plan
	coordinate
	execute movement
	maintain balance

D).  Processes

1). Cerebral cortex sends message of intent to initiate voluntary muscle movement.
2). Receives information on body position and muscle tension and visual input.
3). Calculates best way to coordinate muscles
4). Cerebellum sends "blueprint" of movement to cerebral motor cortex.
5). Also sends stimulus to the midbrain and thus the spinal cord

VII). Limbic System

 Structures located throughout the cerebral hemisphere & diencephalon.
Function:

	Emotional feeling brain
	recognizes angry, fearful expressions and assesses danger &elicits fear response.
	Expresses emotions and resolves mental conflict.
	Connects with prefrontal lobe so there is a strong relationship between feelings and cognitive thought.
	Output relayed through the hypothalamus.

VIII). Protection of the Brain

A). Skull
B). Cerebral Spinal Fluid: Forms a cushion
C). Meninges

1). Consists of 3 connective tissue membranes external to the central nervous system.

2).  Layers of the Meninges

i) Dura Mater

	Tough meninx (meninges layer)
	2 layered fibrous connective tissue.

ii). Arachnoid Mater

Forms the subdural space under the dura mater.

iii). Pia Mater

Delicate connective tissue that clings to the brain.

IX). Blood-Brain Barrier

Capillaries in the brain are the least permeable in the entire body

(However in some areas it is very porous ie. hypothalamus)

Glucose, amino, acids, and electrolytes move freely however toxins, metabolic wastes etc. do not.
Fats and fat-soluble molecules move freely.

This includes various drugs & alcohol