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QUICK STUDY NOTES FOR NEURO
Planes of the Brain:
Regions of the Nervous System:
1) spinal cord
(2) medulla oblongata = myelencephalon
(3) pons and cerebellum = metencephalon
(4) midbrain = mesencephalon
(5) telencephalon whose most prominent structure is the cerebral cortex.
Because of the tremendous development of the telencephalon dorsally and
laterally, the medulla, pons, midbrain and diencephalon cannot be seen
externally except from the ventral surface
(6)diencephalon = posterior part of the forebrain that connects the midbrain with
the cerebral hemispheres, encloses the third ventricle, and contains the thalamus
and hypothalamus
Grey and White Matter (p. 8-9)
Grey matter:
- Grey Matter regions of the central nervous system (CNS), the brain and
spinal cord, contrast with the white matter regions.
- grey matter is the areas where the actual "processing" is done whereas
the white matter provides the communication between different grey
matter areas and between the grey matter and the rest of the body.
- grey matter is so-called because in section it has a grey colour due to all
the grey nuclei in the cells that make it up. In fact, in the living body, grey
matter is pink.
- neurons in the grey matter consist of neuronal cell bodies and their
dendrites, the short protrusions that communicate with immediately
neighbouring neurons in the CNS.
White matter:
- located beneath the grey matter, in the internal regions of the cerebrum
and cerebellum
- white matter consists of myelinated fibre tracts or neuronal axons
- In contrast with the neurons of the white matter, grey matter neurons do
not contain long axons that transmit the nerve impulses to more distant
regions of the CNS
- About 40% of the human brain is made up of gray matter whereas 60% is
white matter. However the gray matter consumes about 94% of the total
oxygen used by the brain
Ganglia:
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Ganglia are a collection of nerve cell bodies (or nuclei) usually located
outside of CNS, in the peripheral nervous system ex. Dorsal root ganglia
Dorsal root ganglia contain the cell bodies of the sensory spinal nerves
Cranial Nerves:
"Oh Oh Oh, To Touch And Feel Vamped Girls, Very Sexy & Hot." A profane
example is "Some Anatomists Like F**king, Others Prefer S & M" for the external
carotid artery branches. Medical mnemonics are quite common, see [1]
(http://www.medicalmnemonics.com).
1. Oholfactory
2. Oh optic
3. Oh oculomotor
4. To trochlear
5. Touch- trigeminal
6. And abducens
7. Feelfacial
8. Vamped-vestibulocochlear
9. Girlsglossopharyngeal
10. Very- vagus
11. Sexy- accessory
12. Hothypoglossal
Meninges
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Beneath the skin is bone (your skull). Below the skull are three special
coverings called the meninges. Meningitis is an infection of the meninges.
The outer layer of the meninges is called the dura mater or just the dura.
The dura is tough and thick and it can restrict the movement of the brain
within the skull. This protects the brain from movements that may stretch
and break brain blood vessels.
The middle layer of the meninges is called the arachnoid. The inner layer,
the one closest to the brain, is called the pia mater or just the pia.
Subdural hematoma:
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acute subdural hematoma (SDH) is a rapidly clotting blood collection
below the inner layer of the dura but external to the brain and arachnoid
membrane
Two further stages, subacute and chronic, may develop with untreated
acute SDH
Each type has distinctly different clinical, pathological, and imaging
characteristics.
Falx cerebri:
- the larger of the two folds of dura mater separating the hemispheres of the
brain that lies between the cerebral hemispheres and contains the sagittal
sinuses
- sickle shaped
- extends into the medial longitudinal fissure
Tentorium
- horizontal shelf of dura that sits between occipital lobe and cerebellum
CEREBRAL CORTEX AND FUNCTION
Frontal Lobe: Most anterior, right under the forehead.
Functions:
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How we know what we are doing within our environment (Consciousness).
How we initiate activity in response to our environment.
Judgments we make about what occurs in our daily activities.
Controls our emotional response.
Controls our expressive language.
Assigns meaning to the words we choose.
Involves word associations.
Memory for habits and motor activities.
Observed Problems:
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Loss of simple movement of various body parts (Paralysis).
Inability to plan a sequence of complex movements needed to complete
multi-stepped tasks, such as making coffee (Sequencing).
Loss of spontaneity in interacting with others.
Loss of flexibility in thinking.
Persistence of a single thought (Perseveration).
Inability to focus on task (Attending).
Mood changes (Emotionally Labile).
Changes in social behavior.
Changes in personality.
Difficulty with problem solving.
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Inablility to express language (Broca's Aphasia).
Parietal Lobe: near the back and top of the head.
Functions:
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Location for visual attention.
Location for touch perception.
Goal directed voluntary movements.
Manipulation of objects.
Integration of different senses that allows for understanding a single
concept.
Observed Problems:
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Inability to attend to more than one object at a time.
Inability to name an object (Anomia).
Inability to locate the words for writing (Agraphia).
Problems with reading (Alexia).
Difficulty with drawing objects.
Difficulty in distinguishing left from right.
Difficulty with doing mathematics (Dyscalculia).
Lack of awareness of certain body parts and/or surrounding space
(Apraxia) that leads to difficulties in self-care.
Inability to focus visual attention.
Difficulties with eye and hand coordination.
Occipital Lobes: Most posterior, at the back of the head.
Functions:
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Vision
Observed Problems:
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Defects in vision (Visual Field Cuts).
Difficulty with locating objects in environment.
Difficulty with identifying colors (Color Agnosia).
Production of hallucinations
Visual illusions - inaccurately seeing objects.
Word blindness - inability to recognize words.
Difficulty in recognizing drawn objects.
Inability to recognize the movement of an object (Movement Agnosia).
Difficulties with reading and writing.
Temporal Lobes: Side of head above ears.
Functions:
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Hearing ability
Memory aquisition
Some visual perceptions
Catagorization of objects.
Observed Problems:
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Difficulty in recognizing faces (Prosopagnosia).
Difficulty in understanding spoken words (Wernicke's Aphasia).
Disturbance with selective attention to what we see and hear.
Difficulty with identification of, and verbalization about objects.
Short-term memory loss.
Interference with long-term memory
Increased or decreased interest in sexual behavior.
Inability to catagorize objects (Catagorization).
Right lobe damage can cause persistant talking.
Increased aggressive behavior.
BRAIN STEM
Deep in Brain, leads to spinal cord.
Functions:
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Breathing
Heart Rate
Swallowing
Reflexes to seeing and hearing (Startle Response).
Controls sweating, blood pressure, digestion, temperature (Autonomic
Nervous System).
Affects level of alertness.
Ability to sleep.
Sense of balance (Vestibular Function).
Observed Problems:
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Decreased vital capacity in breathing, important for speech.
Swallowing food and water (Dysphagia).
Difficulty with organization/perception of the environment.
Problems with balance and movement.
Dizziness and nausea (Vertigo).
Sleeping difficulties (Insomnia, sleep apnea).
CEREBELLUM (Located at the base of the skull.)
Functions:
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Coordination of voluntary movement
Balance and equilibrium
Some memory for reflex motor acts.
Observed Problems:
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Loss of ability to coordinate fine movements.
Loss of ability to walk.
Inability to reach out and grab objects.
Tremors.
Dizziness (Vertigo).
Slurred Speech (Scanning Speech).
Inability to make rapid movements.
Ventricular System
Functions of the Cerebral Spinal Fluid (CSF)
1) The CNS (brain and spinal cord) are rendered buoyant by the cerebrospinal
fluid medium in which they are suspended. This provides the nervous system
with support and protection against rapid movements and trauma.
2) The CSF is believed to be nutritive for both neurons and glial cells.
3) The CSF provides a vehicle for removing waste products of cellular
metabolism form the nervous system. In this capacity, it functions like a lymphatic
system.
4) The CSF plays a role in maintaining the constancy of the ionic composition of
the local microenvironment of the cells of the nervous system. The extracellular
space of the brain freely communicates with the CSF compartment and therefore
the composition of the two fluid compartments is similar.
5) The presence of a number of biologically active principles (releasing factors,
hormones, neurotransmitters, metabolites ) within the CSF suggests that it may
function as a transport system.
6) The H + and CO 2 concentrations in the CSF (pH) may affect both pulmonary
ventilation and cerebral blood flow.
7) Since the CSF and brain extracellular space are in continuity analysis of the
composition of the CSF provides diagnostic information about the normal and
pathological state of the nervous system function.
Causes of Hydrocephalus (interruption of CSF flow):
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Congenital defects
Meningitis
Head injury
Brain hemorrhage (see Brain symptoms)
Brain tumor
Hydrocephalus as a complication: Other conditions that might have
Hydrocephalus as a complication might be potential underlying causes of
Hydrocephalus:
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Cerebral Aneurysm
Meningitis
Spina bifida
Subarachnoid hemorrhage