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Brain Structures
Hypothalamus – found below the thalamus it caps the brain stem and forms the walls of the 3rd
ventricle. It is the main visceral control center and vital in overall body homeostasis functions including:
1. Autonomic Control Center
2. Center for Emotional Response
3. Body Temperature Regulation
4. Regulation of food Intake
5. Regulation of water balance
6. Regulation of sleep-wake cycles
7. Control of Endocrine Function Hypothalamus
Pituitary Gland – sits securely
in the sella turcica of the
sphenoid bone. It is shaped
like a pea at the end of a
stalk.
It is a major endocrine organ
secreting at least 9 hormones
including growth hormone, thyroid
stimulating hormone and follicle
stimulating hormone to name a
few. Pituitary Gland
Corpus Callosum – is
the largest commissure
which by definition
connect the two
hemispheres of the brain.
It lies superior to the
lateral ventricles.
it allows the two hemispheres
to coordinated function
Corpus Callosum
Pons – “bridge” is the bulge in the brainstem between the midbrain and the medulla oblongata.
Is chiefly composed of conduction fibers which complete the pathway between the higher brain
centers and the spinal cord. Pons
Medulla Oblongata – the most inferior part of the brain stem. It blends into the spinal cord at the base.
Plays a crucial role in the autonomic reflex center. Important visceral motor nuclei include
1. Cardiovascular center
2. Respiratory centers
3. Additional centers that control Vomiting, hiccupping, swallowing, coughing and sneezing.
Medulla Oblongata
Cerebellum – “Small
Brain” accounts for about
11% of total brain mass.
Located dorsal to the
medulla and pons.
Processes information from the
cerebral motor cortex and
visual and equilibrium
pathways, and “instructs”
motor centers which result in
proper balance, posture,
smooth coordinated skeletal
muscle movements. Cerebellum
Thalamus – “inner room” is a deep well hidden brain region. It contains a large number of nuclei.
Each nuclei receives and deciphers information from the cerebral cortex and other areas “relay station”. The thalamus plays an integral in mediating sensation, motor activities, cortical arousal, learning and memory.
Thalamus
Midbrain – a
conduction pathway
between the higher
and lower brain
centers. Contains the
corpora quadrigemina
Midbrain
Corpora quadrigemina –“quadruplets” which is 4 raised dome-like protrusions on the dorsal midbrain surface.
1. Visual reflex center –coordinates head and eye movements to follow moving objects.
2. Auditory Reflex center –reflexive response to sharp sounds that cause you to turn your head towards and startling sound “startle reflex”
CorporaQuadrigemina
Cerebrum – gray matter
localizes and interprets
sensory inputs.
1. Controls voluntary and
skilled skeletal muscle
activity.
2. Functions in intellectual
and emotional processing
3. Important in initiation of
skeletal muscle movements
Cerebrum
Frontal Lobe
Temporal Lobe
Cerebellum
Parietal Lobe
Occipital Lobe
Are continuous spaces which reside inside
the tissue of the brain
They are continuous with the central
canal of the spinal cord.
They are full of Cerebral Spinal Fluid
Brain Ventricles
CSF (Cerebral Spinal Fluid) – is found in
and around the brain and spinal cord.
It forms and liquid cushion and gives
buoyancy around the CNS. The CSF
reduces the weight of the brain by 97%
and prevents the brain from crushing
itself.
It also protects the CNS from trauma and
helps nourish the brain.
Choroid Plexus – these structures hang from the roof of the ventricles and produce CSF.
Arachnoid Villi – knob like projections which protrude through the dura mater into the superior sagittal sinus. CSF is absorbed into the venous blood of the dural sinus
here.
ChoroidPlexus
ArachnoidGranulations
1st and 2nd Ventricles “lateral ventricles” are deep
within either cerebral hemisphere.
Are large C-shaped ventricles
Foramen of Munroe – “interventricular foramen”
which attaches the lateral ventricles to the narrow 3rd
ventricle
1st and 2nd Ventricles
3rd Ventricle
Thin medial ventricle
Aqueduct of Sylvius
“cerebral aqueduct”
connects the 3rd and forth
ventricle
3rd Ventricle
Aqueduct of Sylvius
4th Ventricle –
lies in dorsal to the pons and
superior medulla. It is
continuous with the central
canal of the spinal cord.
Central Canal of Spinal
Cord -
Continues down the
spinal cord from the
ventricles of the brain.
Central Canal
4th Ventricle
“Water on the brain” is a condition where
the CSF cannot be drained or reabsorbed.
CSF accumulates and exerts pressure on the
brain
Hydrocephalus is
treated by inserting
a shunt into the
ventricles to drain
the excess fluid into
a vein in the neck
or abdomen.
Meninges – “membrane” are three connective tissue membranes that lie just outside the CNS (Brain and Spinal Cord). Their functions include;
1. Cover and protect the CNS
2. Protect blood vessels and enclose the venous sinuses
3. Contain CSF
4. Form partitions in the skull
Dura Mater –
“tough mother” is the strongest layer.
Two layered sheet of fibrous connective tissue.
Arachnoid -
Forms a loose brain covering.
Separated from the dura matter by a serous cavity “Subdural space”
The “subdural space” is filled with fluid
Dura MaterSuperior Sagittal
Sinus
Arachnoid
Subarachnoid Space
Web-like extensions span this space and attach the arachnoid to the pia matter.
This space is filled with CSF and large blood vessels
Pia Mater
“gentle mother” is composed of delicate connective tissue and is full of tiny blood vessels.
This is the only layer that clings tightly to the brain following every contour.
Meningitis is the inflammation of the protective membranes covering the central nervous system (meninges)
Meningitis may develop in response to a number of causes, most prominently bacteria, viruses and other infectious agents, but also physical injury, cancer, or certain drugs
Brain with Meningitis
Dura
Mater
“forked spine” results from the incomplete formation of the vertebral arches
is a developmental birth defect involving the neural tube: incomplete closure of the embryonic neural tube results in an incompletely formed spinal cord.
the vertebrae overlying the open portion of the spinal cord do not fully form and remain un fused and open
This allows the abnormal portion of the spinal cord to stick out through the opening in the bones
3 Types
1. Spina bifida occulta – not severe results in a small tuft of hair on the back and has no neurological ramifications.
2. Spina bifida meningocele – more severe, a sac-like cyst protrudes from the child’s spine. The cyst contains CSF and Meninges.
3. Spina bifida myelomeningocele – similar to above only the cyst contains neural structures. The more neurological structures the cyst contains the more neurological impairment.
There is no treatment
for the neurological
defects caused by
spina bifida.
Doctors will perform
surgery to close the
vertebral column to
prevent further
damage and infection.An infant with Spina Bifida
