Central Nervous System. Divisions of the Brain Brainstem Medulla oblongata extension of spinal...
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Transcript of Central Nervous System. Divisions of the Brain Brainstem Medulla oblongata extension of spinal...
Central Nervous System
Divisions of the Brain Brainstem
Medulla oblongata 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 Small, located above midbrain, below cerebrum Consists of 2 major structures: hypothalmus and
thalmus Hypothamus:
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 Thalmus
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.
cerebrum Largest and upper most part of brain Ridges – convolutions or gyri Grooves – sulci, deep grooves – fissures
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 4 major lobes of the brain named for
bones Frontal, Occipital, Temporal, parietal
Cerebral cortex – gray matter, surface of cerebrum White matter (tracts) makes up most of
cerebrum exception is basal ganglia (produce automatic
movements and posture, ex. Parkinson disease
Brain disorders Cerebrovascular accident (CVA) – stroke –
hemorrhage or cessation of blood flow through vessels in brain, neurons die If damage occurs in a motor control section of brain,
movement ceases Cerebral palsy – damage to brain tissue
Prenatal infections, trauma to the head before, during, after birth, reduced oxygen to brain
Spastic paralysis – involuntary contractions of affected muscles
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
Seizure Seizure – sudden bursts of abnormal
neuron activity Range from mild to severe
Epilepsy – recurring or chronic seizures 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
Spinal cord 2 way conduction
Ascending tracts – to brain Descending tracts – from the brain
Primary reflex center Cut in the spinal cord results in no
communication Anesthesia – loss of sensation Paralysis – loss of the ability to make
voluntary movements
Coverings Meninges – touch, fluid-containing
membrane 3 layers
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 Cerebrospinal fluid (CSF) – fills
subarachnoid spaces in brain and spinal cord and ventricles in brain 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