CH 14 Flashcards
TBI’s (concussion, contusion)
- drowsiness
- lack of focus
- confusion
- amnesia
- headache
Rostral
toward the forehead
Caudal
toward the spinal cord
Cerebrum
83% of brain volume
Cerebellum
50 % of the neurons, 2nd largest region.
Longitudinal fissure
deep groove that separates cerebral hemispheres
Corpus callosum
thick nerve bundle at bottom of longitudinal fissure that connects hemispheres.
Brainstem
-major components
- diencephalon
- midbrain
- pons
- medulla oblongata
Gray matter
the seat of neuron cell bodies, dendrites, and synapses.
- form cortex over cerebrum and cerebellum
- fors nuclei deep within brain.
White matter
bundles of axons
- lies deep to cortical gray matter, opposite than the spinal chord.
- composed of tracts, or bundles of axons, that connect one part of the brain to another, and to the spinal cord.
Meninges
3 connective fissure membranes the envelop the brain.
- dura mater, arachnoid mater, pia mater
- protect the brain and provide structural frame work for it arteries and veins.
Dura mater
2 layers
- periosteal
- meningeal
-cranial dura mater is pressed closely against cranial bones
(no epidural space)
-layers separated by DURAL SINUSES
Arachnoid mater
- subarachnoid space separates it from pia mater below.
- Subdural space separates it from dura mater above in some places.
Pia mater
-very thin membrane that follows contours of brain, even dipping into sulci.
Meningitis
inflammation of the meninges.
- serious disease of infancy and childhood.
- especially between 3 mons and 2 years.
- cause by bacterial and virus invasion of the CNS by way of the nose and throat.
Bacterial meningitis
can cause swelling of the brain, enlargement of the ventricles, and hemorrhage.
- headache, nausea, and stiff neck.
- diagnosed by examining the CSF for bacteria (spinal tap)
lumbar puncture (spinal tap)
draws fluid from subarachnoid space between two lumbar vertebrae.
-L2-L3 or L3-L4
Choroid plexus
spongy mass of blood capillaries.
Ependyma
Neuroglia that lines the ventricles and covers choroid plexus.
-produces CSF
Cerebrospinal fluid
clear, colorless liquid that fills the ventricles and canals of CNS.
-Brain produces and absorbs 500mL/day.
slides 24-28
Functions of CSF
- Buoyancy
- protection (shaken child syndrome and concussions do occur from severe jolting)
- Chemical stability (sleep)
Brain is only___% of the adult body weight, and receives ____% of the blood
2% ; 15%
A 10 second interruption of blood flow may cause ___.
loss of consciousness
A 1 to 2 minute interruption can cause ______.
impairment of neural function.
Going 4 mins without blood cause ______.
irreversible brain damage.
2 points of entry the must be guarded.
- blood capillaries throughout the brain tissue.
- capillaries of the choroid plexus.
Blood-brain barrier
protects blood capillaries through brain tissue.
Astrocytes
reach out and contact capillaries with their perivascular feet.
- induce endothelial cells to form tight junctions that completely seal off gaps between them.
- anything leaving the blood must pass through the cell and not between them.
Endothelial cells
can exclude harmful substances from passing to the brain tissue while allowing necessary ones to pass.
Blood-CSF barrier
protects the brain at the choroid plexus
- blood barrier system is HIGHLY permeable to water, glucose, and lipid soluble substances like oxygen, carbon dioxide, alcohol, caffeine, nicotine, and anesthetics.
- SLIGHTLY permeable to sodium, potassium, chloride, and the waste products urea and creatinine.
circumventricular organs
CVO’s
places in the third and fourth ventricles where the barrier is absent.
- blood has direct access to brain.
- a route for invasion (HIV)
- cocaine and meth damage BBB.
Medulla oblongata
- cardiac center
- vasomotor center
- respiratory center
- reflex center
Pons
communicates with cerebellum.
-sleep and posture
Substantia nigra
produce dopamine
degeneration of neurons leads to tremors of ______ disease.
parkinsons
reticular formation
sleep and consciousness :
-plays a role in states of consciousness such as alertness and sleep.
Habituation (thalamus): process in which the brain learns to ignore repetitive info.
cerebellum
monitors muscle contractions and aids in motor coordination.
- evaluation of sensory input
- timekeeping center
Lessions in the cerebellum may result in ____ and ____.
emotional overreactions and trouble with impulse control.
FAS=ADHD
Diencephalon
- thalamus
- hypothalamus
- epithalamus
Thalamus
- gateway to cerebral cortex
- memory and emotional functions of the limbic system.
Hypothalamus
major control center of autonomic nervous system and endocrine system.
- autonomic effects
- thermoregulation
- food and water intake
- rhythm of sleep and walking
- memory
- emotional behavior
Epithalamus
very small mass of tissue composed of:
- pineal gland: secretes melatonin
- habunela
frontal lobe
- voluntary motor functions
- motivation,foresight, planning, memory, moods emotion, social judgment and aggression, smell, and taste.
parietal lobe
receives and integrates general sensory info
-taste
occipital lobe
visual center
temporal lobe
areas for haring, smell, learning, memory.
Insula
(hidden)
-taste, speech
3 types of tracts
- projection tracts
- commissural tracts
- association tracts
Association tracts
connect different regions within the same cerebral hemisphere
long association fibers
connect different lobes of a hemisphere to each other
short association fibers
connect different gyri within a single lobe
_______is carried out in the gray matter of the cerebrum.
Neural integration
cerebral gray matter is found in 3 places:
- cerebral cortex
- basal nuclei
- limbic system
Cerebral cortex
layer covering the surface of the hemispheres.
- 2 to 3 mm thick
- 40% of brain mass
- 14-16 billion neurons
Neocortex
6 layered tissue that is about 90% of the human cerebral cortex.
-relatively recent in evolution
Basal nuclei
masses off cerebral gray matter buried deep in the white matter, lateral tp thalamus.
- receives input from SUBSTANTIA NIGRA of the midbrain and motor areas of cortex.
- sends signals back to both locations
- motor control
3 brain centers form basal nuclei:
- caudate nucleus
- putamen
- globus pallidus
Lentiform nucleus
putamen and globus pallidus collectively
Corpus striatum
putamen and caudate nucleus collectively
Limbic system
-prominent parts:
center of emotion and learning.
(olfaction)
- cingulate gyrus
- hippocampus
- amygdala
Cingulate gyrus
arches over the top of the corpus callosum in the frontal and parietal lobes. (receives inout from other limbic structures)
Hippocampus
in the medial temporal lobe; memory (fact memory)
Amygdala
- gratification:
- aversion:
immediately rostral to the hippocampus (emotional memory)
- sensations of pleasure or reward.
- sensations of sorrow or fear.
higher brain functions
sleep, memory, cognition, emotion, sensation, motor control, and language.
integrative functions of the brain focus mainly on the ____cerebrum, but involve combined action of ______.
cerebrum; multiple brain levels
alpha waves 8 to 13 Hz
- awake and resting with eyes closed and mind wandering.
- suppressed when eyes open or performing a mental task.
Beta waves 14 to 30 Hz
- Eyes open and performing mental tasks.
- Accentuated during mental activity and sensory stimulation.
Theta waves 4 to 7 Hz
- drowsy or sleeping adults
- if awake and under emotional stress
Delta waves (high amplitude) <3.5 Hz
-deep sleep in adults
Electroencephalogram (EEG)
monitors surface electrical activity of brain waves.
- useful for studying normal brain functions as sleep and consciousness.
- in diagnosis of degenerative brain disease, metabolic abnormalities, brain tumors, etc.
restorative effect
- brain glycogen and ATP levels increase in non-REM sleep
- memories strengthened in REM sleep.
Stage 1 of sleep
- feel drowsy, close eyes, begin to relax.
- often feel drifting sensation, easily awakened.
- alpha waves
stage 2 of sleep
- pass into light sleep]
- exhibits (REM)
Stage 3 of sleep
- moderate to deep sleep-
- about 20 mins after stage 1
- theta and delta waves appear
- muscles relax and vital signs fall.
stage 4 of sleep
deep sleep
-slow wave sleep: EEG dominated by low frequency, high amplitude delta waves.
REM
- vital signs increase, brain use more oxygen than when awake.
- sleep paralysis stronger
dreams occur in both rem and non rem.
_____ active in REM sleep
Parasympathetic nervous system.
- causing constriction of pupils.
- erection of the penis and clitoris.
Cognition
the range of mental processes by which we acquire and use knowledge
-thought, reasoning, memory, imagination, etc.
(association are of cerebral cortex have above function… 75% of brain tissue)
Amnesia
defects in declarative memory: inability to describe past events.
Procedural memory
- anterograde amnesia
- retrograde amnesia
ability to tie ones shoes
- unable to store new info.
- person cannot recall things known before injury.
Hippocampus
important memory forming center.
- does not store memories.
- organizes sensory and cognitive info into long term.
long term memories are stored in various areas of the _____.
cerebral cortex
Vocabulary and memory of familiar faces are stored in superior _______.
temporal lobe
memories of one’s plans and social roles are stored in the ______.
prefrontal cortex
Cerebellum (memory)
helps learn motor skills
Amygdala (memory)
emotional memory
Phones Gage
railroad worker; serve head injury.
- injury to ventromedial region of both frontal lobes.
- personality change
Prefrontal cortex functions
planning, moral judgment, and emotional control.
feelings come from ___ and ____.
hypothalamus and amygdala.
Sensory homunculus
upside down sensory map of the contralateral side of body
Somatotopy
point for point correspondence between and area of the body and an area of the CNS.
Dyskinesias
movement disorders cause by lesions in the basal nuclei.
Ataxia
clumsy awkward gait (cerebellum)
Wernicke area
- permits recognition of spoken and written language and create plan of speech.
- when we intend to speak, Wernicke area formulates phrases according to learned rules of grammar.
- transmits plan of speech to broca area.
Broca area
- generates motor program for the muscles of the larynx, tongue, cheeks, and lips.
- transmits program to primary motor cortex for commands to the lower motor neurons that supply relevant muscles.
Aprosody
flat emotionless speech (produced by lesions in affective language area)
Aphasia
any language deficit from lesions in same hemisphere (usually left) containing wernicke and broca areas.
Nonfluent (broca) aphasia
- lesion in broca area
- slow speech, difficulty in choosing words, using words that only approximate the correct word.
Fluent (wernicke) aphasia
- lesion in wernicke area
- speech normal and excessive, but uses senseless jargon.
- cannot comprehend written and spoken words.
Anomic (wernicke) aphasia
can speak and understand speech, but cannot identify written words or pictures.
Cerebral lateralization
the difference in the structure and function of the cerebral hemispheres
left hemisphere
categorical hemispheres
- specialized for spoken and written language.
- sequential and analytical reasoning (math and science).
- breaks info into fragments and analyzes it in a linear way.
Right hemisphere
representational hemisphere
- perceive info in a more integrated holistic way
- imagination
- music and art
- patterns and spatial relationships.
- comparisons of senses.
Lateralization develops with age:
males exhibit more lateralization than females and suffer more functional loss when one hemisphere is damaged
-ex: stroke
