The brain

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Anatomy & Physiology
right & left connected by large fiber
tract: corpus callosum
 cover most of other 3 parts
 surface: elevated ridges = gyri separated
by shallow grooves = sulci
 Fissures deeper grooves separate
regions of brain

separates cerebral hemispheres
 other fissures separate brain into lobes
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spaces in brain filled
with CSF
connected to
subarachnoid space
(around brain &
spinal cord) and
central canal of
spinal cord
parietal lobe posterior to central sulcus
 receives impulses from sensory
receptors (not special senses), interprets
them

◦ pain recognition
◦ temperature
◦ light touch
anterior to central sulcus in frontal lobe
 major voluntary motor tract

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visual area

auditory & olfactory areas

Brocca’s Area: ability to speak
◦ @ base of precentral gyrus (usually only on
left side)
◦ injury  inability to correctly vocalize words

http://www.youtube.com/watch?v=_0aNILW6
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
http://www.youtube.com/watch?v=c6kRP41y
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anterior frontal lobe: higher intellectual
reasoning
 complex memories: frontal/ temporal lobe
 all facets of speech:
occipital/temporal/parietal lobes

gray matter in brain that is NOT in
cerebral cortex
 functions: help regulate voluntary motor
activity by modifying instructions sent
to skeletal muscle by primary motor
cortex

Parkinson’s
 Huntington’s

sits atop brain stem
 enclosed by cerebral hemispheres
 major parts:

◦ Thalamus
◦ Hypothalamus
◦ Limbic system
◦ Epithalamus

relay station for sensory impulses
passing thru to sensory cortex
ANS center
 role in:

◦ temperature control
◦ water balance
◦ metabolism

regulates autonomic & endocrine
functions in response to emotional
stimuli (“reacting” brain vs. cerebral
cortex being “thinking” brain)
◦ set level of arousal
◦ motivation
◦ reinforcing behaviors
◦ rage, love, memory, empathy
~size of thumb in diameter & ~ 3 inches
long
 3 parts:

1. midbrain
2. pons
3. medulla oblongata
knots of capillaries w/in each ventricle
 produce & secrete CSF (cerebral spinal
fluid)

smallest, uppermost part of brain stem
 cerebral aquaduct: tiny canal that runs
thru midbrain connecting 3rd & 4th
ventricles
 contains reflex centers for vision,
hearing

“bridge”
 rounded structure that protrudes below
midbrain
 contains apneustic (produces deep,
prolonged inspirations) & pneumotatic
center (inhibits inspiration)

most inferior part of brain stem
 inferior border merges into spinal cord
 centers: heart rate, BP, breathing,
swallowing, vomiting

large, cauliflower-like
 projects dorsally from under occipital
lobe
 2 hemispheres
 convoluted surface
 provides precise timing for skeletal
muscle activity
 controls balance & equilibrium

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Head injuries are leading cause of
accidental death in USA.
Concussion: dizziness, “see stars”, briefly
lose consciousness; No permanent brain
damage
Contusion: result of marked tissue damage.
Cerebrum: may maintain consciousness
Brainstem: coma
Cerebral Edema: swelling of brain due to
inflammatory response to injury/ initially
conscious neuro signs deteriorate (think
edema or hemorrhage)
stroke
 3rd leading cause of death in USA
 occur when blood circulation to brain is
interrupted

◦ vessel could be blocked (temporary or
permanent) or hemorrhaging

characterized by:
◦ abrupt onset of persisting neurological
symptoms that arise from destruction of brain
tissue
common causes:
◦ intracerebral hemorrhage
◦ emboli
◦ atherosclerosis of cerebral arteries
1.
2.
3.
4.
5.
6.
7.
8.
9.
hypertension
hypercholesterolnemia
heart disease
narrowed carotid arteries
hx of TIAs (transient ischemic attacks)
diabetes
smoking
obesity
excessive alcohol intake

Thrombolytic:
◦ clot-dissolving drug: tissue plasminogen
activator (t-PA) greatly improved prognosis
for CVA
◦ aspirin (makes plts slippery  fewer clots)
◦ blood thinners
Aphasia: from damage to left side
cerebrum where language centers are
 Motor Aphasia:

◦ damage to Broca’s area
◦ loss of ability to speak

Sensory Aphasia:
◦ loss of ability to understand written or
spoken word
Transient Ischemic Attack
 “mini-stroke”
 due to temporary restriction of blood
flow
 symptoms last 5 – 50 minutes
 “red flags” that warn impending & more
serious CVAs
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most common type of dementia
>10% population > age 65
4th leading cause of death in US
characterized by progressive loss of reasoning &
ability to care for oneself
cause of most cases unknown but…
◦ genetic factors
◦ environmental or lifestyle factors
◦ normal aging process
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