The Brain

Six regions in the adult brain

• Cerebrum
• Diencephalon
• Mesencephalon
• Pons
• Cerebellum
• Medulla oblongata

cerebrospinal fluid (CSF)

clear, colourless liquid that carries oxygen, glucose, and other needed chemicals from the blood to the neurons

What ventricles does the brain consist of? what do they carry?

2 lateral ventricles
third ventricle
fourth ventricle

They carry CSF throughout the brain

What is the site of CSF production?

Choroid plexuses, which are specialized networks of capillaries

Cranial meninges

• Continuous with the three layers of the spinal
cord
• Folds of dura mater help stabilize the position of
the brain
• Falx cerebri
• Tentorium cerebelli
• Falx cerebelli

What does CSF do?

• CSF cushions delicate neural structures
• Supports the brain
• Transports nutrients, chemical messengers, and
waste products

Pathway of CSF

• Produced at the Choroid plexus,
• Travels through the lateral and medial
apertures to the subarachnoid space,
• Diffuses across the arachnoid granulations into
the superior sagittal sinus

Blood Brain Barrier

• Blood brain barrier isolates neural tissue from
general circulation
• Incomplete barrier in areas:
• Parts of the hypothalamus
• Pituitary gland
• Pineal gland
• Choroid plexus

Medulla Oblongata

• Connects the brain with the spinal cord
• Contains relay stations and reflex centers
• Olivary nuclei
• Cardiovascular (regulates heartbeat and diameter of blood vessels) and respiratory rhythmicity (regulates basic rhythm of breathing)
centers
• Reticular formation begins in the medulla
oblongata and extends into more superior
portions of the brainstem

Pons

• Sensory and motor nuclei for four cranial nerves
• Nuclei that help control respiration
• Nuclei and tracts linking the cerebellum with the
brain stem, cerebrum and spinal cord
• Ascending, descending and transverse tracts

Cerebellum

• Adjusts postural muscles and tunes on-going
movements
• Cerebellar hemispheres
• Anterior and posterior lobes
• Vermis
• Flocculonodular lobe
• Superior, middle and inferior cerebellar
peduncles link cerebellum with brain stem,
diencephalon, cerebrum, and spinal cord
• Interconnects the two cerebellar hemispheres
The

Mesencephalon

• The tectum (roof) contains the corpora
quadrigemina
• Superior and inferior colliculi
• The mesencephalon contains many nuclei
• Red nucleus
• Substantia nigra
• Cerebral peduncles
• RAS headquarters

Superior Colliculi

Round bumps in mesencephalon

Reflex arcs pass through the govern movement of the eye

Inferior Colliculi

Round bumps in mesencephalon

Reflex arcs pass through that govern the auditory pathway

Diencephalon is composed of what?

• Epithalamus
• Hypothalamus
• Thalamus

Thalamus

• Final relay point for ascending sensory
information
• Coordinates the activities of the cerebral cortex
and basal nuclei

Hypothalamus

Controls somatic motor activities at the
subconscious level
• Controls autonomic function
• Coordinates activities of the endocrine and
nervous systems
• Secretes hormones
• Produces emotions and behavioral drives
• Coordinates voluntary and autonomic functions
• Regulates body temperature
• Coordinates circadian cycles of activity

Limbic System

Plays a part in emotions and behavioral drives

Separations of Cerebral Cortex

• Surface contains gyri and sulci or fissures
• Longitudinal fissure separates two
cerebral hemispheres
• Central sulcus separates frontal and
parietal lobes
• Temporal and occipital lobes also
bounded by sulci

Basal Nuclei

Deep within each cerebral hemisphere

Caudate nucleus
• Globus pallidus
• Putamen
• Control muscle tone and coordinate learned
movement patterns

Motor and sensory areas of the cerebral cortex

• Primary motor cortex of the precentral
gyrus directs voluntary movements
• Primary sensory cortex of the postcentral
gyrus receives somatic sensory information
• Touch
• Pressure
• Pain
• Taste
• Temperature

Association areas

Control our ability to understand sensory
information and coordinate a response
• Somatic sensory association area
• Visual association area
• Somatic motor association area

General interpretive and speech areas

General interpretive area
• Receives information from all sensory
areas
• Present only in left hemisphere

Speech center
• Regulates patterns of breathing and
vocalization

cortex functions and hemispheric differences

Prefrontal cortex
• Coordinates information from secondary and
special association areas
• Performs abstract intellectual functions

Hemispheric differences
• Left hemisphere typically contains general
interpretive and speech centers and is
responsible for language based skills
• Right hemisphere is typically responsible for
spatial relationships and analyses

Electroencephalogram (EEG)

Measures brain activity
• Alpha waves = healthy resting adult
• Beta waves = concentrating adult
• Theta waves = normal children
• Delta waves = normal during sleep