Transcript Central Nervous System - Woodstown

Central Nervous System
Divisions of the Brain
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Brainstem
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Medulla oblongata
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extension of spinal cord
Contains the cardiac, respiratory and vasomotor
centers (control heartbeat, blood vessel diameter)
Consists of white and gray matter intermingled
Pons
Midbrain
Diencephalon
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Small, located above midbrain, below cerebrum
Consists of 2 major structures: hypothalmus and
thalmus
Hypothamus:
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Pituitary gland is an extension of hypothalmus
Major control over most major organs
Make hormones secreted by pituitary gland
Secrete releasing hormones into blood to the anterior
pituitary gland
Helps regulate water balance, body temperature, sleep
cycles and appetite and many emotions
Diencephalon
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Thalmus
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Dumb bell shaped gray matter, above
hypothalmus
Axons go into cerebellum
Helps produce sensations, associates
sensations with emotions and plays a role in
the arousal or alerting mechanism
Cerebellum
Second largest part of human brain
 Arbor vitae – tree of life, gray matter on
outside, white matter inside
 Produce smooth, coordinated movements,
maintain equilibrium and sustain normal
postures.
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cerebrum
Largest and upper most part of brain
 Ridges – convolutions or gyri
 Grooves – sulci, deep grooves – fissures
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Longitudinal fissure – divides into left and
right
Find also the central sulcus, lateral fissure
Corpus callosum – connects left and
right hemisphere of the brain
cerebrum
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4 major lobes of the brain named for
bones
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Frontal, Occipital, Temporal, parietal
Cerebral cortex – gray matter, surface of
cerebrum
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White matter (tracts) makes up most of
cerebrum
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exception is basal ganglia (produce automatic
movements and posture, ex. Parkinson disease
Brain disorders
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Cerebrovascular accident (CVA) – stroke –
hemorrhage or cessation of blood flow through
vessels in brain, neurons die
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If damage occurs in a motor control section of brain,
movement ceases
Cerebral palsy – damage to brain tissue
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Prenatal infections, trauma to the head before, during,
after birth, reduced oxygen to brain
Spastic paralysis – involuntary contractions of affected
muscles
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Hemiplegia – 1 side of body
Paraplegia – both legs
Triplegia – both legs, 1 arm
Quadriplegia – all 4 appendages
Degenerative brain disorders
Destruction of neurons in the brain
 Affects memory, attention span,
intellectual capacity, personality and
motor control = dementia
 Alzheimer Disease (AD) – lesions on
cerebral cortex
 Huntington disease (HD) – chorea –
involutary purposeless movements
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Seizure
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Seizure – sudden bursts of abnormal
neuron activity
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Epilepsy – recurring or chronic seizures
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Range from mild to severe
Can be caused by tumors, trauma, or chemical
imbalances, most idiopathic
Medications block neurotransmitters in
affected areas of the brain.
Spinal cord
Average of 17 – 18 inches
 From occipital bone to L1 vertebrae
 core is made up of gray matter
 Outer part is white matter – spinal tracts
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Spinal cord
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2 way conduction
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Ascending tracts – to brain
Descending tracts – from the brain
Primary reflex center
 Cut in the spinal cord results in no
communication
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Anesthesia – loss of sensation
Paralysis – loss of the ability to make
voluntary movements
Coverings
Meninges – touch, fluid-containing
membrane
 3 layers
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Dura mater – tough outer layer
Pia mater – innermost membrane, covers
spinal cord
Arachnoid mater – between dura and pia
mater, cob web like
Meningitis – infection or inflammation of
meninges
Fluids
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Cerebrospinal fluid (CSF) – fills
subarachnoid spaces in brain and spinal
cord and ventricles in brain
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2 lateral ventricles and third ventricle
CSF is continuously begin made from fluid
filtering out of choroid plexus and into
ventricles and continues to circulate
around the brain and spinal cord
 Hydrocephalus – water on the brain –
accumulation of CSF in ventricles
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