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brain
- protected by meninges
- floats in CSF
- weighs 3lbs
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CSF
- located in ventricles
- produced by choroid plexus
- drains into thorax
- mechanical protection
- ideal chemical environment
- exchanges nutrients and waste between blood and brain
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choroid plexus
- network of capillaries that hangs off the 3rd ventricle
- produces CSF
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hydrocephalus
production of more CSF than is drianed
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ventricles
- cavities within the brain
- 4 ventricles: lateral (2), 3rd, 4th
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lateral ventricles
midline of the brain
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3rd ventricle
small slit between R/L thalamus
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4th ventricle
space between brain stem and cerebellum
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parts of the brain
- brainstem
- diencephalon
- cerebellum
- cerebrum
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brainstem
- medulla oblongata
- pons
- midbrain
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medulla oblongata
- continuation of the spinal cord that begins at the foramen magnum and ends at the pons
- 1-2" long
- pyramids on front surface
- olive on front surface
- all ascending and descending nerves pass through
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pyramids
two bulges on front surface of MO where ascending and descending nerves decussate
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decussate
nerve fibers cross over
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olive
elevated region on front of MO that relays proprioceptive sensations up to cerebellum
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proprioception
awareness of position and location of body parts without having to look
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medulla oblongata functions
- cardiac center: regulates rate and strength of heartbeat
- basic rhythm of breathing (2 sec in/3 sec out)
- vasomotor center: regulates diameter of blood vessels
- controls swallowing, vomiting, coughing, sneezing
- reticular formation
- origin of cranial nerves C8-C11
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pons
- bridge or relay station that connects spinal cord to the upper parts of the brain
- major regulator of breathing
- 2 breathing centers: apneustic and pneumotaxic
- origin of cranial nerves C5-C8
- all motor signals coming from cerebrum or cerebellum pass through pons
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apneustic center
keeps lungs from overfilling
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pneumotaxic center
allows you to hold breath
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midbrain
- connects upper and lower brain
- origins of cranial nerves C3 and C4
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cerebral peduncles
part of the midbrain that anchors cerebrum to brainstem
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tegmentum
part of midbrain that helps both frontal lobe of cerebrum and cerebellum with fine motor control
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cerebral aqueduct
small tube in midbrain that connects 3rd and 4th vesicles
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lemniscus
white matter region of midbrain that helps convey sensations of touch, pressure, vibration
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tectum
- posterior midbrain
- contains corpora quadrigemina, superior colliculi, inferior colliculi
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corpora quadrigemina
part of tectum that controls movements of the eyes, head, neck, trunk
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superior colliculi
part of tectum that controls eye movement in response to visual stimulation
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inferior colliculi
part of tectum that controls head movement in response to sound
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thalamus
- part of the brain where sensations such as pain, temperature, touch, vision, and sound are first interpreted
- gateway to the cerebrum
- controls emotion and some memory
- plays a role in cognition
- contains 2 hemispheres connected by intermediate mass
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hypothalamus
- directly below the thalamus
- 4 regions: mammillary, tuberal, supraoptic, preoptic
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mammillary region
region of hypothalamus that controls reflexes
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tuberal region
region of hypothalamus that contains infundibulum
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infindibulum
connects hypothalamus to pituitary
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supraoptic region
region of hypothalamus where optic nerves cross over on way to upper brain
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preoptic region
region of hypothalamus that controls all autonomic functions
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functions of the hypothalamus
- HR
- gland secretion
- smooth/cardiac muscle contraction
- peristalsis and gastric juice secretion
- body temp
- appetite and thirst
- sleep
- blood glucose levels
- memory
- sex drive
- rage, aggression, and fear
- pleasure and pain
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cerebellum
- little brain
- mostly gray matter
- contains arbor vitae (white matter region)
- separated from cerebrum by transverse fissure
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arbor vitae
tree shaped region of white matter in the cerebellum
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functions of the cerebellum
- gross body movements and coordination
- posture and balance
- skilled movements of the finger
- emotional development
- controls feelings of anger and pleasure
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reticular formation
- vague region of the brain throughout the MO, pons, midbrain, thalamus, hypothalamus, and cerebellum
- plays a role in sleep
- controls HR and muscle tone
- pain modulation
- habituation
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pain modulation
how a person deals with pain
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habituation
ability to block out repeated stimuli related to sound
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cerebrum
- large brain
- controls all memory
- speak and calculate
- taste and smell
- remember past and plan for future
- shape, color, movement
- translate words to thoughts and vice versa
- interprets sound
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cortex
- outside gray matter of the brain
- folded
- contains convolutions and fissures
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convolutions
folds in the cortex of the cerebrum
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longitudinal fissure
most prominent fissure that separates the cerebrum into R/L hemisphere
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sucli/gyri
shallow grooves in the cortex
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corpus callosum
fiber of the cerebrum that connects R/L hemisphere
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association fibers
fibers of the cerebrum that transmit info between regions in the same hemisphere
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projection fibers
fibers of the cerebrum that transmit info from cerebrum down to spinal cord and vice versa
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commissural fibers
fibers of the cerebrum that transmit info from a point in one hemisphere to the exact same point in the opposite hemisphere
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motor area
- entirely in frontal lobe
- controls all motor activity in the body
- 2 subregions: primary motor and motor speech
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primary motor area
- controls voluntary contraction of every muscle in the body
- almost all fibers decussate in MO
- damage to this region causes paralysis
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motor speech area
- aka Broca's area
- allows translation of thought to speech
- controls muscles of mouth and throat
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sensory area
- sensory
- visual
- auditory
- gustatory
- olfactory
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primary sensory area
- aka somatosensory
- parietal lobe
- localization of sensations
- (sensory area)
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primary visual area
- occipital lobe
- interprets sensations of shape, color, movement
- (sensory area)
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primary auditory area
- temporal lobe
- receives sensations of sound, rhythm, pitch
- (sensory area)
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primary gustatory area
- parietal lobe
- receives all sensation related to taste
- (sensory area)
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primary olfactory area
- temporal lobe
- receives all sensations related to smell
- (sensory area)
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association areas
- somatosensory
- visual
- gnostic
- auditory
- premotor
- frontal eye field
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somatorsensory area
- parietal lobe
- analyzes sensation received from the primary sensory area and allows reaction
- determines size, shape, texture of an object without actually seeing it
- (association area)
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visual area
- occipital lobe
- uses past visual experiences and relates them to the present
- (association area)
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gnostic area
- occipital, temporal, parietal lobes
- receives, interprets, allows reaction to input from vision, sound, taste, smell
- (association area)
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auditory area
- aka Wernicke's area
- temporal lobe
- translates words to thoughts
- differentiates between music, noise, speech
- (association area)
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premotor area
- frontal lobe
- controls complex sequental learned motor activities and forms a memory bank
- (association area)
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frontal eye field area
- frontal lobe
- controls voluntary scanning movement of the eye
- (association area)
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limbic system
- aka emotional brain
- found throughout the brain stem
- controls feelings of anger, fear, pleasure
- contains hippocampus
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hippocampus
region of limbic system that converts short term memory to long term memory
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blood brain barrier
- membrane that surrounds entire brain (excluding hypothalamus)
- protects brain from toxins
- hypothalamus must sample body fluids
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electroencephalogram (EEG)
- measures electrical activity of the brain
- 4 waves: alpha, beta, theta, delta
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alpha wave
awake but resting with eyes closed
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beta wave
- brain extremely active
- lots of sensory input
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theta wave
- normal in young children and in adults with emotional stress
- brain tumor if seen in stress-free adults
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delta wave
- sleeping adult or infant < 1 if away
- brain damage if seen in awake adult
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