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Anatomy of the brain
1. BENGKEL PENGURUSAN
PESAKIT “HEAD INJURY”
UNTUK JURURAWAT DI
HOSPITAL KKM NEGERI
SELANGOR
25 JUN 2010
DI HOSPITAL SUNGAI BULOH
ANATOMY OF THE BRAIN
2. • Total surface area of the
cerebral cortex = 2,500
cm2 (2.5 square feet).
• In order to fit it in the
skull, it is crumpled up.
• The weight of the brain in
normal young adults
ranges from 1050 g to
1800 g
An Overview
3. Although the two halves may look alike
their functions are very different
An Overview
brain can be divided into three main parts
1. The rhombencephalon or
hindbrain
-medulla oblongata or
myelencephalon
-metencephalon
Pons
Cerebellum
2. The mesencephalon or midbrain
3. The prosencephalon or forebrain
-Diencephalon
large thalamus
the much smaller
hypothalamus,
-Telencephalon -two cerebral
hemispheres
five main parts or lobes: lobus frontalis, lobus
parietalis, lobus temporalis, lobus occipitalis and
lobus limbicus
4. What is a brain made of?
• A neuron is a nerve cell.
• The brain is made up of approximately 100 billion
neurons.
• Neurons have specialized projections called
dendrites and axons.
• Dendrites bring information to the cell body and
axons take information away from the cell body.
• The axon of a motor neuron in the spinal cord
that innervates a muscle in the foot can be
about 3 feet in length.
• They are separated by small gap called a
synapse
• Total number of synapses in cerebral cortex is
about 60 trillion. This is equal to about a half-
billion synapses per cubic millimeter.
5. • There are 10-50 times as many Glia cells as
neurons.
What is a brain made of?
There several types of glial cells;
Insulate the neurons (myelin) Oligodendrocytes
Nourish and support the neurons Astrocytes
Produce Spinal Fluid Ependymal Cells
Remove debris Microglia
• In addition to each neuron, there are 50 times as
many glial cells, and many blood vessels filling the
space between them.
• The neurons make up less than 8% of the cells in
the brain
• The majority of the remaining cells are called
“Glia”, which means glue.
8. Arachnoid
• The Arachnoid is like a sheet of cellophane
that is draped over the brain.
• There is a space between the Arachnoid and the brain called the subarachnoid
space.
• In this space is the spinal fluid and the blood vessels
9. Pia
• The Pia is a single layer of cells that coat the brain
surface, much like linoleum on a floor
The arrows
outline the
space between
the arachnoid and pia;
the subarachnoid space
10. Dural Partitions
• In a few regions, the dura creates large partitions, separating large parts of the
brain
11. The Cerebrum: Features
• Sulci – Small grooves dividing the gyri
– Central Sulcus – Divides the Frontal
Lobe from the Parietal Lobe
• Longitudinal Fissure – Divides the two Cerebral Hemispheres
• Transverse Fissure – Separates the Cerebrum from the
Cerebellum
• Sylvian/Lateral Fissure – Divides the Temporal Lobe from the
Frontal and Parietal Lobes
• Gyri – Elevated ridges “winding” around
the brain.
• Fissures – Deep grooves, generally
dividing large regions/lobes of the brain
12. The Cerebrum
Grey matter is composed of cell
bodies of the neurons
White matter is the axons and dendrites
of the neurons – bundles of “cables”
connecting regions of the brain and
spinal cord.
Deep within the brain are large clusters of neuron cell bodies
called nuclei or ganglia. They are also grey matter
13. The Cerebrum
Occasionally, the Insula is considered the fifth lobe. It is located deep to the Temporal Lobe.
Transverse
Fissure
Sylvian/Lateral
Fissure
Central Sulcus
14. The Cerebrum: Frontal Lobe
• The Frontal Lobe of the brain is located deep to the
Frontal Bone of the skull.
• It plays an integral role in the following functions or
actions:
- Memory Formation
- Emotions
- Decision Making/Reasoning
- Personality
15. The Cerebrum: Frontal Lobe
• Primary Motor Cortex (Precentral Gyrus)
– Cortical site involved with controlling movements of the body.
• Broca’s Area – Controls facial
neurons, speech, and language
comprehension.
Located on Left Frontal Lobe.
Broca’s Aphasia – Results in the
ability to comprehend speech, but
the decreased motor ability (or
inability) to speak and form words.
• Olfactory Bulb - Cranial Nerve I,
Responsible for sensation of Smell
16. The Cerebrum: Parietal Lobe
• The Parietal Lobe of the brain is located deep to the
Parietal Bone of the skull.
• It plays a major role in the following functions or
actions:
1. Senses and integrates sensation(s)
2. Spatial awareness and perception
(Proprioception - Awareness of body/ body parts in
space and in relation to each other)
17. Parietal Lobe: Cortical Regions
• Primary Somatosensory Cortex (Postcentral Gyrus)
– Site involved with processing of tactile and proprioceptive information.
• Somatosensory Association Cortex
- Assists with the integration and
interpretation of sensations relative to body
position and orientation in space. May assist
with visuo-motor coordination.
• Primary Gustatory Cortex
– Primary site involved with the interpretation
of the sensation of Taste.
18. The Cerebrum: Occipital Lobe
• The Occipital Lobe of the Brain is located deep to the
Occipital Bone of the Skull.
• Its primary function is the processing, integration,
interpretation, etc. of VISION and visual stimuli.
19. Occipital Lobe: Cortical Regions
• Primary Visual Cortex – This is the primary area of the brain responsible for
sight -recognition of size, color, light, motion, dimensions, etc.
• Visual Association Area –
Interprets information acquired
through the primary visual cortex.
20. The Cerebrum: Temporal Lobe
• The Temporal Lobes are located on the sides of the
brain, deep to the Temporal Bones of the skull.
• They play an integral role in the following functions:
- Hearing
- Organization/Comprehension of language
- Information Retrieval (Memory and Memory
Formation)
21. Temporal Lobe: Cortical Regions
• Primary Auditory Cortex – Responsible for hearing
• Primary Olfactory Cortex –
Interprets the sense of smell once it
reaches the cortex via the olfactory
bulbs. (Not visible on the superficial
cortex)
• Wernicke’s Area – Language
comprehension.
Located on the Left Temporal Lobe.
Wernicke’s Aphasia – Language
comprehension is inhibited. Words
and sentences are not clearly
understood, and sentence formation
may be inhibited or non-sensical.
24. • Arcuate Fasciculus - A white matter tract that connects Broca’s Area and
Wernicke’s Area through the Temporal, Parietal and Frontal Lobes.
Allows for coordinated, comprehensible speech.
•Damage may result in: Conduction Aphasia
- Where auditory comprehension and speech articulation are
preserved, but people find it difficult to repeat heard speech.
Connectivity
25. • In the individual person, speech depends on the integrity
of specific cortical areas that usually lie only in one
hemisphere
• It is normally the left one in right-handed persons.
• In left-handed persons, it may be the right or the left
hemisphere
Dominant Hemisphere
28. • Deep within the cerebral hemispheres, large grey masses of nerves
cells called nuclei, form components of the basal ganglia
• 4 basal ganglia
• The caudate nucleus
• The putamen
• The Globus pallidus (paleostriatum)
• The amygdala (oldest of the BG- archistriatum)
Basal Ganglia
Lentiform nucleus
Corpus
striatum
• Amygdala located ventral to corpus
striatum in medial part of temporal
lobe, receives olfactory inputs but
plays no role in olfactory perception.
• Pathological processes include
abnormal involuntary movement
(dyskinesia) and significant
alterations of muscle tone
29. • The thalamus involved in the relay and distribution of most but not all
sensory and motor signals to specific regions of the cerebral cortex
Thalamus
• The relay nuclei in turn supply the
primary and secondary sensory areas
of the cerebral cortex.
• Sensory signals generated in all types
of receptors are projected via complex
pathways to specific relay nuclei in the
thalamus.
30. • It controls major endocrine functions by secreting hormones (i.e. oxytocin
and vasopressin) that induce smooth muscle contractions of reproductive,
digestive and excretory systems)
Hypothalamus
• Specific regions of the hypothalamus are
also involved with the control of
sympathetic and parasympathetics
activities, temperature regulation, food
intake, reproductive cycle, emotional
expression and behaviour.
• The hypothalamus lies below the thalamus in the walls and floor of the third
ventricle
31. • The brainstem comprises the medulla oblongata, the pons and the
midbrain
Brain stem
• The midbrain lies above pons containing
major motor supply to the muscles controlling
eye movements.
• The medulla transmits all signals between
the spinal cord and the higher part of the
brain, also governs mechanisms such as
heartbeat, blood pressure and breathing
• The pons lies above the medulla, associated
with sensation and movement of the face
32. • It lies behind the pons and medulla oblongata and fills the greater part of
the base of skull
Cerebellum
• The cerebellum serves as a sort of
regulator and coordinator of nerve impulses
between the brain and the muscles.
• It influences upon equilibrium, muscle tone
and the coordination of voluntary motor
function.
• It connected to midbrain, pons and medulla via
superior peduncles
middle peduncles
inferior peduncles
• It contains a pair of lateral lobes (hemispheres) and midline vermis
33. Brain Circulation
• Although the brain comprises
only about 2% of the body
weight it uses about 20% of
the body's blood supply and
consumes 15-20% of the
oxygen
• The human brain contains around
400 miles of blood vessels.
41. Cerebrospinal Fluid
CSF
• CSF is actively secreted
by the brain. CSF is
constantly being made,
circulates and is
reabsorbed into the blood
stream.
• Total volume of cerebrospinal
fluid = 125-150 ml
• The entire volume of
cerebrospinal fluid turns
over 3 to 4 times per day
• CSF is made at a rate of
about 30cc per hour
• The CSF resides in the
subarachnoid space
