Regions of the Brain
1.
2.
3.
4.
Cerebral hemispheres (cerebrum)
Diencephalon
Brain stem
Cerebellum
1. Cerebrum
Surface lobes of the
cerebrum
Frontal lobe
Parietal lobe
Occipital lobe
Temporal lobe
Figure 7.13a
1. Cerebrum
Figure 7.13c
2. Cerebrum
Figure 7.13a
3. Brain Stem
• Attaches to the spinal cord
• Parts of the brain stem
– Midbrain
– Pons
– Medulla oblongata
4. Cerebrum
• Cerebral Hemispheres (Cerebrum)
– The surface is made of ridges (gyri) and grooves (sulci)
– A gyri is an elevated ridge of cerebral tissue.
– Inward folds of cerebral tissue are
called fissures or sulci.
Layers of the cerebrum
Gray matter—outer layer in the cerebral cortex composed mostly of
neuron cell bodies
White matter—fiber tracts deep to the gray matter
Corpus callosum connects hemispheres
Basal nuclei—islands of gray matter buried within the white matter
Gray matter is composed of cell bodies
of neurons.
White matter is composed of fiber tracts
.
Nuclei
deep within the cerebral white matter are
collectively called basal nuclei (ganglia).
4. TERMS
• A bundle or fibers that provides for
communication between different parts of the
CNS is called a process. Like corpus callosum
• A bundle of fibers that carries impulses
between the periphery and CNS areas is called
a nerve.
5. Diencephalon
Intermediate mass
Figure 7.16
6. Brain Structures
• Medulla oblongata- most important autonomic center of
the brain & contains autonomic centers regulating heart
rate, respiration, and other visceral activities.
• Corpora quadrigemina- located in the midbrain; contains
reflex centers for vison and hearing.
• Cerebellum- coordinates complex muscular movements.
• Corpus callosum- large fiber tract connecting cerebral
hemispheres.
• Pituitary gland & pineal body- part of the endocrine system
• Cerebral aqueduct- canal that connects the third and fourth
ventricles
• Thalamus- contains the intermediate mass
Protection of the Central Nervous
System
•
•
•
•
•
Scalp and skin
Skull and vertebral column
Meninges
Cerebrospinal fluid (CSF)
Blood-brain barrier
Trauma to base of brain
• Base of brain houses the brain stem, which
houses most of the vital autonomic centers.
Controls  heart rate, respiration, blood
pressure.
Protection of the Central Nervous
System
Figure 7.17a
8. Meninges
• Dura mater-outermost layer; tough fibrous
connective tissue,
– falx cerebri, a subdivision of dura mater that separates
the right and left cerebral hemispheres
– A dural fold that attaches the cerebrum to the crista
galli of the skull
• Arachnoid layer
– Middle layer
– Web-like; delicate with cottony fibers
• Pia mater-innermost vascular layer covering the
brain; follows every convolution
– Clings to the surface of the brain
Meninges
Figure 7.17b
8. Cerebrospinal Fluid (CSF)
• Similar to blood plasma composition
• choroid plexus- structure that forms the
cerebrospinal fluid
• Forms a watery cushion to protect the brain
• Circulated in arachnoid space, ventricles, and
central canal of the spinal cord
• Arachnoid villi drains cerebrospinal fluid into
venous blood in the dural venous sinuses
10. Ventricles and Location of
the Cerebrospinal Fluid
Choroid plexus
Figure 7.18a–b
10. Ventricles and Location of
the Cerebrospinal Fluid
1. Lateral ventricles
7. Dural sinuses
6
.
5.
2.
3
.
4
.
Lateral ventricle third ventricle  cerebral aqueduct of midbrain  fourth ventricle
- central canal  subarachnoid space  arachnoid villi  dural sinuses
Figure 7.18c
Blood-Brain Barrier
• Includes the least permeable capillaries of the
body
• Excludes many potentially harmful substances
• Useless as a barrier against some substances
– Fats and fat soluble molecules
– Respiratory gases
– Alcohol
– Nicotine
– Anesthesia
Traumatic Brain Injuries
• Concussion
– Slight brain injury
– No permanent brain damage
• Contusion
– Nervous tissue destruction occurs
– Nervous tissue does not regenerate
• Cerebral edema
– Swelling from the inflammatory response
– May compress and kill brain tissue
Cerebrovascular Accident (CVA)
• Commonly called a stroke
• The result of a ruptured blood vessel
supplying a region of the brain
• Brain tissue supplied with oxygen from that
blood source dies
• Loss of some functions or death may result
Alzheimer’s Disease
• Progressive degenerative brain disease
• Mostly seen in the elderly, but may begin in
middle age
• Structural changes in the brain include
abnormal protein deposits and twisted
fibers within neurons
• Victims experience memory loss, irritability,
confusion, and ultimately, hallucinations
and death
Cranial Nerves
•
PNS: Cranial Nerves
• I Olfactory nerve—sensory for smell
• II Optic nerve—sensory for vision
• III Oculomotor nerve—motor fibers to eye
muscles
• IV Trochlear—motor fiber to eye muscles
PNS: Cranial Nerves
• V Trigeminal nerve—sensory for the face;
motor fibers to chewing muscles
• VI Abducens nerve—motor fibers to eye
muscles
• VII Facial nerve—sensory for taste; motor
fibers to the face
• VIII Vestibulocochlear nerve—sensory for
balance and hearing
PNS: Cranial Nerves
• IX Glossopharyngeal nerve—sensory for taste;
motor fibers to the pharynx
• X Vagus nerves—sensory and motor fibers for
pharynx, larynx, and viscera
• XI Accessory nerve—motor fibers to neck and
upper back
• XII Hypoglossal nerve—motor fibers to
tongue
PNS: The Cranial Nerves
Table 7.1 (1 of 4)
PNS: The Cranial Nerves
Table 7.1 (2 of 4)
PNS: The Cranial Nerves
Table 7.1 (3 of 4)
PNS: The Cranial Nerves
Table 7.1 (4 of 4)