Three connective tissue mebranes that lie external to the CNS

Dura Matter 

Arachnoid Matter

Pia Matter

Cover and Protect CNS

Protect Blood Vessels and Enclose venous sinuses

Contain Cerebrospinal Fluid

Form partitions within the skull

Dura Matter

"The Tough Mother"

Leathery Strong Menis composed of two fibrous connective tissue

Periosteal Layer-Outer layer lining the bones (only in brain)

Meningeal Layer-Inner Layer covering the brain and extending into the vertebral column

Meningeal layer 

Dural Sinuses

Falx cerebri 

Falx cerebelli

Tentorium cerebelli

runs along the bermis of the cerebellum

The middle meninx which forms a loose brain covering

Seperated from the dura mater by the subdrual space

Arachnoid villi protruce superiorly and permit CSF to be absorbed into venous blood 

Pia Mater

"Gentle Mother"

Deep menix composed of delicate connective tissue that clings tightly to the brain

Floowos every convolution of the brain

Contains many tiny blood vessels

Cerebrospinal fluid

Liquid Cushion 

Water solution similar to blood plasma

provides bouancy to CNS organs

Location of CSF

Cerebralspinal fluid

Inside the CNS- Brain Ventricles and central canal of the spinal cord

Outside the CNS- in subarachnoid space

150 ml in volume

Approx 1/2 Cup

Replaces itself every 8 hours

Clear Colorless Liquid 

Reduces weight of CNS organs by 97%

Formed from blood plasma

Not buffered like most body fluids

carefully controls water soluble solutes

CSF- Functions

Prevents the brain from crushing under its own weight 

Protects the CNS from blows and other trauma 

Nourishes the brain and carries chemical signals throughout it

Assists in waste removal 

Clusters of capillaries that form tissue fluid filters--in which hange from the roof of each ventricle 

Each have ion pump which allows them to alter ion concentrations of the CSF

Help cleanse the CSF by removing wastes

Cnetral Cavity surrounded by gray matter core

External to which is white matter composed of myelinated fiber tracts

Similar to spinal cord but with additional areas of gray matter

Cerebellum has gray matter in nuclei

Cerebrum has nuclei and additional gray matter in the cortex

Are fluid filled spaces within the brain 

Filled with CSF and lined with ependmal cells 

Lateral Ventricle

Third Ventricle 

Fourth Ventricle

Lateral Ventrical 

Characteristics

and Function 

Paired 

C or Wishbone deep in the cerebral hemisphere

Septum pellucidum

Interventricular Foramen- A channel between the lateral and Third Ventrical through which the CSF empties

Third Ventrical

Characteristics and Function 

A space shaped like a silver dollar located on the brain called the diencephalon 

Cerebral Aqueduct-  A thin canal that connects the third and fourth ventricals

Fourth Ventrical

Characteristic and Function 

It is continuous with the central canal of the spinal cord

Contains apertres that connect the ventricals with the subarachnoid space

Lateral Apertures-Openings of the side walls

Median aperture-Opening on the roof

2 Cerebral Hemispheres

Forms the superior part of the brain and makes up 83% of its mass

Contains Ridges (gyri), Shallow grooves (sulci)

and Deep Grooves (fissures)

Three Regions: Cortex, White Matter and Basal Nuclei

Cortex-- A surface layer of gray matter (cerebral cortex)

Basal Nuclei--A deep gray island of tissue in the CNS

White Matter

Long Medial fissure that divides the let and right cerebral hemispheres

Falx Cerebri: Infolding of the drua matter called dura septa which dips into the longitudinal fissure limiting excessive brain movement

Major Lobes, Gyri and Sulci of the Cerebral Hemisphere

Deep Sulci divide the hemispheres into 5 lobes

Frontal, Parietal, temporal, occipital, and insula

Cental Sulcus- Posterior Border

Parieto-Occipital Sulcus-- Seperates the parietal and occipital lobes

Transverse fissure-- separates the occipital lobe from the cerebellum

Tenorium Cerebelli-- A dural septa that extends into the transverse cerebral fissure

Lateral Sulcus-- Separates the temporal from the parietal and frontal lobes

the internal 5th lobe

It is covered by portion of the temporal parietal and frontal lobes

Superfical Gray Matter, accounts for 405 of the mass of the brain

Enables sensation, communication memory, understanding and voluntary movements

Each Hemisphere controls opposite side of the body

No functional area acts alone, conscious behavior involves the entire cortex

All neurons of the cortex are interneurons

-Neurons before and after

Functional Areas of the Cerebral Cortex

Three Types of functional areas

Motor Areas- Control Voluntary Movement

Sensory Areas-Conscious Awareness of Sensation

Association Areas- Integrate diverse information 

Conscious Awareness of Sensation 

Occur in the parieta, insular, temporal and occipital lobes

Primary Somatosensory Cortex

Primary Visual Area

Primary Auditory Cortex

Olfactory Area

Gustatory Area

Primary Somatosensory Cortex

Located in the postcentral Gyrus

Receives information from the skin and skeletal muscles

Exhibits spatial discrimination-- the ability of the neurons to indenify the body region being stimulated

Located on the extreme posterior tip of the occipital lobe

largest of all sensory area

Receives visual information that origionates on the retina 

Not on the surgace but is a small area of the frontal lobe above the orbits

Taste

Not on the surface but is a small area within the insula just inderneath the temporal lobe

Multimodal--Recieving imputs from multiple senses and sending output to multiple areas

Allows us to give meaning to the inormation we recieve, store it in memory, and tie it to previous experiences and knowledge

Anterior Association Area

Posterior Area

Limbic Association Area

AKA Prefrontal Cortex

Located in the anterior portion of the forntal lobe

Involved with intellect, cognition, recall, and personality

Necessary for judgement, reasoning persistence, and conscience

Important in recognising patterns and faces

Binding different sensory inpouts into coherent whole

Includes Wernicke's Area- Involved in understanding written and spoken language

Primary Motor Cortex 

Pre Motor Cortex

Brocas Area

Located in the precenral Gyrus 

Pyramidal Cells whise axons project to the spinal cord without synapses

Allows conscious control of precise, skilled voluntary movements (ex typing, playing a musical instrunment)

Located anterior to the precentral gyrus 

Controls learned, reetitous or patterened Motor Skills

Coordinates simultaneous or sequential actions

Involved in the planning of movements

Present in one hemisphere (usually the Left)

A motor speech area that directs muscles of the tongue

Is active as one prepares to speak

Mylinated Fibers

It is responsible for communication between the cerebral cortex and lower CNS center

Commissures

Corpus Callosum

Association Fibers

Projection Fibers

Connect corresponding gray areas of the two hemispheres (transfer information from right the left)

Masses of gray matter found deep with in the crticalw white matter

Motor Dampener

Inhibit antagonistic and uncessary movement

Consists of three parired structures

thalamus

Hypothalamus 

Epithalamus

Bean looking 

Mediates sensation, motor activites, cortical arousal, learning andmemory

Acts as the relay station for almost all sensory information 

Decides where information will be send sensory, motor or association area

Located below the thalamus; it caps the brainstem

mammillary bodies:

Relay station for the olfatory pathways

Infudnibulum- stalk of the hypothalamus;connects to the pituitary gland

main visceral control center of the body 

Autonomic Control Center--regulates blood pressure, rate and force of heartbeat, digestive tract mobility, rate and depth of breathing 

Center for emotional response; preception of pleasure, fear, rage

Maintains normal body temperature (sweating vs shivering)

Regulates feelings of hunger and satiety

Regulates sleep and sleep cycle 

Regulates water balance and thirst

Pineal gland- Extends from the posterior border and secretes melatonin

Melatonin- A homrone involved with sleep regulation, sleep wake cycles and mood

Along with the hypothalamus, helps to regulate the sleep wake cycle

Consists of three regions

Midbrain, pons, and medulla oblongata

Simular to the spinal cord but contains embedded nuclei

Controls automatic behaviors necessary for survival 

Provides the pathway for tracts between higher and lower brain centers

Located between the diencephalon and the pons

Midbrain structures include 

Cerebral peduncles

Cerebral Aqueduct 

Various Nuclei

Bulging brainstem rgion between the midbrain and bedulla oblongata 

Fibers of the pons: connect higher brain centers and the spinal cord

Relay impulses between the motor cortex and the cerebellum

Most inferior part of the brain stem

Pyramids- Two longitudinal Ridges formed by coticospinal tracts descending from the motor cortex

Olives- Lateral to the pyramids, sensory infomation on the state of the stretch  of muscles and joints

Autonomic Reflex Center 

Cardiovascular control Center- Adjust force and rate of heart contraction

Respiratory Centers- Control rate and depth of breathing 

Additional Centers- Regulate vomiting, hiccuping, swallowing, coughing, and sneezing

Hypothalamus relays its instructions to the medulla which carries them out

makes up 11% of the brains mass

provides precise timing and appropriate patterns of skeletal muscle contraction for smooth coordinated movement

Cerebellar activity occurs subsonsciously 

Two Bilaterally symmetrical hemispheres connected medially by the vermis

Folia- transversly oriented gyri

Neural Arrangment- Gray matter cortex, internal white matter, scattered nuclei

Arbor vita- Distinctive Treelike pattern of the erebellar white matter

Cerebellum receives impulses of the intent to initate volunatry muscle contraction 

Proprioceptors and visual signals "inform" the cerebellum of the body's condition

Cerebellar Cortex calculates the best way to perform a movement

A blueprint of coordinated movement is sent to the cerebral motor cortex

Plays a role in language and problem solving 

Recognizes and predicts sequesnces of events