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.)
![]() |
that is scattered through the brain stem connecting the brainstem, cerebellum and cerebrum with ascending and descending tracts.Network
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