Central Nervous System Flashcards
(81 cards)
1
Q
astrocytes
A
- physically supports neurons
- serves as scaffold during fetal brain development
- induced formation of the BBB
- form neural scar tissue
- help transfer nutrients from the blood to the neurons
2
Q
oligogendrocyes
A
-form myelin sheaths in CNS
3
Q
microglia
A
- defense of the brain as phagocytic scavengers (phagocytosis)
- release nerve growth factor
4
Q
ependymal cells
A
- lines inner cavities of the brain and spinal cord
- contributes to the formation of CSF
- potential to form new neurons and glial cells
5
Q
cerebral spinal fluid (CSF)
A
- surrounds and cushions brain and spinal cord
- shock-absorber to prevent the brain from hitting the skull
- exchanging of materials between neural cells and interstitial fluid surround brain
- constant production and flow out of CNS
- produced in brain ventricles (choroid plexuses)
- exits 4th ventricle
6
Q
blood and oxygen to the brain
A
- depends on constant blood supply
- cannot produce ATP without O2
- uses glucose but does not store any
- resting conditions: brain uses 20% of the O2 and 50% of glucose consumed in the body
7
Q
cerebrum
A
- makes up 80% of total brain weight
- divided into left and right hemispheres
- each hemisphere is divided into lobes (frontal, temporal, occipital and parietal)
- connected by the corpus callosum
8
Q
central nervous system (CNS)
A
- consists of the brain and spinal cord
- receives input from external environment–> CNS sorts and process via interneurons–> efferent neurons carry instructions to desired area
9
Q
somatic nervous system
A
-consists of fibers of motor neurons that supply the skeletal muscle
10
Q
autonomic nervous system
A
-consists of fibers that innervate smooth and cardiac muscles and glands
11
Q
enteric nervous system
A
-extensive nerve network in the wall of the digestive tract
12
Q
interneuron
A
- 99% of all neurons
- lie entirely within the CNS
- receiving information from afferent neuron
- multipolar
13
Q
afferent neuron
A
- afferent division of PNS
- sensory receptor at peripheral end that generates action potentials
- unipolar
14
Q
efferent neuron
A
- lie primarily in the PNS
- cell bodies originate in the CNS
- multipolar
15
Q
DAP
A
- dur mater
- arachnoid mater
- pia
16
Q
dura mater
A
- tough, inelastic covering
- consists of 2 layers
- dural sinuses: blood filled cavities
- venous sinuses: drains venous blood from the brain (returning to heart) and CSF reenters the blood here
17
Q
arachnoid mater
A
- delicate, richly vascularized layer
- “cobwebby” appearance
- subarachnoid space is filled with CSF
18
Q
arachnoid villa
A
- penetrate through gaps in overlying dura into the dural sinus
- CSF is reabsorbed across the surfaces into the circulating blood
19
Q
cerebral cortex
A
- gray mater outter
- white matter central core
- houses basal nuclei
- sensory perception
- voluntary control of movement
- language
- personality traits
- sophisticated mental events, ex. thinking
20
Q
gray matter
A
-organized into 6 well defined layers
-integration of neural input and initiation of neural output
-unmyelinated
Stellate cells- initial processing of info into the cortex
Pyramidal cells- send signals down the spinal cord to effector motor neurons
21
Q
white matter
A
- consists of bundles of nerve fibers that interconnect brain areas
- axons, myelinated
22
Q
somatosensory cortex
A
- front portion of each parietal lobe behind central sulcus
- initial processing and perception of somesthetic and proprioceptive input
- receives input from opposite side of body
- input from specific areas of the body
- distribution map: homunculus
23
Q
somesthetic sensations
A
- sensations from the surface body
- heat, touch, pressure, cold and pain
24
Q
proprioception
A
-awareness of body position
25
primary motor cortex
- front of central sulcus
- controls voluntary movement produced by skeletal muscles
- control muscles on opposite side of body
- motor homunculus
- fine control movements occupy larger area of motor homunculus
- does NOT initiate voluntary movement
- influenced by supplementary motor area, premotor cortex, posterior parietal cortex, cerebellum and basal nuclei
26
broca's area
- location: left frontal lobe near motor areas
| - controls speaking abiliy
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Wernicke's area
- location: left cortex and the juncture of parietal, temporal and occipital lobes
- language comprehension of both spoken and written messages
- responsible for formulating coherent patterns of speech--> broca's area
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left cerebral hemisphere
- logical
- analytical
- sequential
- verbal tasks
- math
- language forms
- philosophy
- process information into fragments
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right cerebral hemisphere
- non-language skills
- spatial perception
- artistic
- musical talents
- sees "big picture"
30
basal nuclei (basal ganglia)
- several masses of gray matter deep within white matter
- inhibit muscle tone throughout the body
- selecting, maintaining purposeful motor activity
- suppressing unwanted patterns of movement
- coordinates slow, sustained contractions
- Parkinson's disease
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Parkinson's disease
- gradual destruction of neurons that release dopamine in the basal nuclei
- motor disturbances: increased muscle tone (rigidity), involuntary/useless/ unwanted movements (resting tremors), slowness in initiation and completing motor behaviors
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thalamus
- reinforces voluntary motor behavior from motor cortex
- "relay station" and synaptic integrating center for sensory input
- helps direct attention to stimuli of interest
- capable of crude awareness of sensations, cannot distinguish location or intensity
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hypothalamus
- collection of nuclei and associated fibers that lie beneath the thalamus
- homeostatic functions
- link between autonomic nervous system and endocrine system
- most involved in directly regulating internal environment
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hypothalamus controls
- body temperature
- thirst and urine output
- food intake
- controls anterior pituitary hormone secretion
- produces posterior pituitary hormones
- uterine contractions and milk ejection
- major autonomic nervous system coordinating center (smooth muscle, cardiac muscle, exocrine glands)
- emotional/behavioral patterns
- participates in sleep-wake cycle
35
limbic system
- includes portions of cerebral lobes, basal nuclei, thalamus and hypothalamus
- utilizes the neurotransmitters norepinephrine, dopamine and serotonin
- associated with emotions, basic survival, sociosexual behavioral patterns, motivation and learning
- EMOTION and overt physical responses associated with these feelings
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limbic system function
- emotions: subjective feelings, moods and physical responses with feelings
- basic behavioral patterns: survival and perpetuation of the species
- motivation: directing behavior and goals
- learning: acquiring knowledge from experience or skill
- memory: storage of acquired knowledge for later use
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short term memory
- lasts seconds to hours
- space: limited
- rapid retrieval
- memory fades quickly and permanently forgotten (unless consolidated into long term)
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long term memory
retained for days to years
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consolidation
the transfer of short term memory traces into long term memory stores
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declarative memories
- "what type memories"
- processed in hippocampus and associated structures
- involve conscious recall
- divided into semantic (fact memories) and episodic memories (memories of events)
41
procedural memories
- "how to memories"
| - processed in cerebellum
42
the prefrontal cortex serves as:
-temporary storage area associated with planning, problem solving, organizing and inhibiting impulses
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vestibulocerebellum
maintenance of balance, control of eye movements
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spinocerebellum
- regulation of muscle tone, coordination of skilled voluntary movement
- ensures the accurate timing of various muscle contractions to coordinate movements involving multiple joints
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cerebrocerebellum
- planning and initiation of voluntary activity
| - storage of procedural memories
46
brain stem
- links spinal cord and higher brain levels
- consists of midbrain, pons and medulla
- centers that control the cardiovascular, respiratory and digestive function
- regulates postural muscle reflexes
- controls overall degree of cortical alertness
- role in sleep-wake cycle
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consciousness
-subjective awareness of the external world and self
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states of consciousness
decreasing order of arousal:
- maximum alertness
- wakefulness
- sleep
- coma
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sleep
- initiated by the brain for the brain
- not accompanied by a reduction in neural activity
- theories: restoration, recovery and memory consolidation
- alternates between slow-wave sleep and paradoxical (REM) sleep
50
slow-wave sleep
- slow waves on the EEG
- occurs in 4 stages, each displaying progressively slower EEG waves with higher amplitude
- little change in brain behavior from the waking state
- stage 1-->2 --> 3-->stage 4--> reverse--> REM
- 80% of sleep
- easily awakened
- considerable muscle tone, frequent shifting
51
paradoxical sleep (REM)
- EEG pattern of an alert, awake person
- after a set of slow-wave sleep
- abrupt inhibition of muscle tone and changes in behavior
- dreams are common
- 20% of sleep
- harder to wake, but can wake up spontaneously
52
white matter tracts
- organized into nerve tracts
- bundles of nerve fibers with a similar function
- begins or ends in a particular area of the brain
- afferent is sensory input that goes through the ascending tracts
- descending tracts relay efferent motor output
53
nerve
- a bundle of peripheral neuronal axons (afferent and efferent)
- enclosed by connective tissue
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reflex
- any response that occurs automatically without conscious effort
- two types: simple and acquired
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simple reflex
- basic
| - built-in, unlearned
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acquired reflex
- conditioned
| - result of practice and learning
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reflex arc
- neural pathway involved in accomplishing reflex activity
| - five components: receptor, afferent pathway, integrating center (CNS), efferent pathway, effector
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Central Nervous system is composed of
Brain and Spinal cord
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Percentage of CNS cells that are Glial cells (neuroglial)
90%
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4 types of glial cells
astrocytes, oligodendrocytes, microglia, ependymal
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What part of the brain is not subject to the BBB
hypothalamus because it needs to sample the blood and release hormones into the blood to maintain homeostasis
62
Functions controlled in Temporal lobe
Hearing, emotion, motivation, memory
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Frontal lobe functions
Broccas area (speech), planning and coordiantion of complex movements, planning for voluntary activity, decision making, personality traits
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presulcus gyrus of frontal lobe function
Primary motor cortex controls voluntary movement
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Division of frontal and parietal lobe
Central sulcus
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front portion of Parietal lobe functions (postsulcus gyrus)
Somatosensory cortex (processing of information such as touch, pressure, heat, cold, pain) and proprioception
67
Parietal lobe functions
integration of somatosensory and visual input for complex movements, (wernickes area) speech understanding
68
Occipital lobe function
sight
69
Gamma waves
Fastest waves with smallest amplitude
associated with peak concentration
Multiple parts of the brain are involved, usually when integrating sights and sounds of a current experience
70
Betta waves
High frequency and low amplitude
When fully awake, focused, alert
dominant during most of the day
When actively thinking, conversing, or focusing on surroundings
71
Alpha waves
lower frequency and larger amplitude than beta waves
present when awake
during periods of calm and relaxation
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Theta waves
slower frequency and larger amplitude than alpha
| when drowsy or light sleep
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delta waves
greatest amplitude and slowest frequency
| deep dreamless sleep
74
Dorsal Horn
Contains cell bodies which receive messages from afferent neurons (sensory)
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Lateral horn
Contains autonomic nerve fibers supplying cardiac and smooth muscle, and exocrine glands
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Ventral horn
Contains cell bodies of Efferent motor neurons supplying skeletal muscle
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What makes up a spinal nerve
Bundles of afferent axons entering the dorsal root and efferent axons leaving the ventral root come together to form a spinal nerve
78
What are the three uncrossed spinal nerve tracks
Dorsal spinocerebellar (ascending), Ventral cortiocspinal (descending, crosses at termination), Vestibulospinal (descending)
79
endoneurium
connective tissue around the axon
80
perineurium
connective tissue around the fasicle
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epineurium
Connective tissue around the nerve. Blood vessels go through this part of the nerve
