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4 main functions of the Nervous System?
- Detect information
- Recognize significance
- Decide on response
- Execute action
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Define afferent pathways
Transmit sensory information from PNS to CNS (sensory neurons)
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Define efferent pathways
Neurons relay information from CNS to effector organs (motor pathway)
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Describe 2 types of efferent pathways
- Autonomic Nervous System- controls internal organs:
- sympathetic system: fight or flight
- parasympathetic system: rest and digest
- Somatic Motor Division-Controls skeletal muscle
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Define reflex pathways
sensory--> CNS--> motor
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Olfactory Nerve
sensory-smell
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Optic Nerve
sensory-vision
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Occulomotor Nerve
motor-eye movement
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Trochlear Nerve
motor-eye movement
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Trigeminal Nerve
- Both:
- sensory-face sensation
- motor-chewing
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Abducens Nerve
motor-eye movement
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Facial Nerve
- Both-
- sensory-anterior taste
- motor-facial expression
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Vestibulocochlear Nerve (auditory)
sensory-Hearing, Balance
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Glossopharyngeal Nerve
- Both-
- sensory-posterior taste
- motor-pharynx, salivary
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Vagus Nerve
Both- larynx, lungs, heart, gastrointestinal (s) (m)
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Accessory Spinal Nerve
motor-movement of neck, viscera, swallowing
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Hypoglossal Nerve
motor-tongue movement
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4 main regions of spinal cord
- cervical (8)
- thoracic (12)
- lumbar (5)
- sacral (5)
- coccyx (1)
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Functional significance of the dorsal part of spinal cord
Posterior, Afferent, sensory-->CNS
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Functional significance of the ventral part of spinal cord
Anterior, Efferent, motor-->PNS/effector organs
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Define ascending tracts
transmit info from spinal cord to brain (rise)
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Define descending tracts
transmit info from brain to spinal cord
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Describe Dura mater
- "Hard, durable mother"
- Outer most layer of meninges, tough fibrous tissue touches bone
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Describe Arachnoid mater
- "spider mother"
- middle layer of meninges, weblike structure touches dura mater, no space between
- -subarachnoid mater-space between arachnoid and pia filled w/CSF
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Describe Pia mater
- "tender, kind mother"
- inner most layer of meninges, adjacent to nerve tissue adheres to brain/spinal cord
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The Ventricular System
- system of 4 ventricles
- Holds CSF (proteins and glucose) providing nourishment and protection
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Describe Blood Brain Barrier
- made of modified capillaries made of endothelial cells that have pores between them. the capillaries that line the brain are also endothelial cells but have tight junctions to reduce space and covered by feet of astrocytes.
- Helps seperate blood circulating in capillaries (which may be carrying toxins) from mixing w the extracellular fliud of the brain.
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List 6 major divisions of brain
- Forebrain:
- -cerebrum
- -diencephalon
-cerebellum
- Brain stem:
- -midbrain
- -pons
- -medulla oblongata
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List components of midbrain and its function
- part of brainstem, conduction pathway between higher and lower brain centers
- components-
- tectum: (roof) responsible for auditory and visual reflexes
- tegumentum:(covering) involved in many unconscious homeostatic and reflexive pathways.
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List functions of pon
- relay info from cerebrum to cerebellum.
- co-operates with medualla oblongata (respiratory rate)
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List components and function of Medulla Oblongata
- components:
- grey matter (visceral muclei) controlling heart rate, blood vessel diameter, resp. rate, coughing, vomiting (autonomic involuntary functions)
white matter contains ascending somatosensory tracts and descending corticospinal tracts (tracts cross midline @ medula or spinal cord)
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Function of cerebellum
- "mini brain"
- motor coordination and balance processes info from cerebral motor cortex , proprioceptors, visual and equilibrium pathways
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List components and functions of diencephalon
- contains
- Thalamus-relay station, memory processing
- Hypothalamus-Homeostasis center
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The Limbic system
- "basic instinct"
- mediates emotional response
- connects to frontal, temporal lobe, thalamus and hypothalamus
- contains:
- amygdala-anger, fear and aggression
- cingulate gyrus-positive and negative emotional response
- hippocampus-learning and memory
- insular cortex-relates visceral/autonomic sensations of emotion to rest of brain
- ex: bear--->HR ,BP increase --->fear
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amygdala
anger, fear and agression
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cingulate gyrus
involved in positive and negative emotional response
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hippocampus
learning and memory
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insular cortex
- relates visceral/autonomic sensations of emotion to rest of brain
- EX: Bear-->increase HR BP-->Fear
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Function of Corpus collosum
Band of tissue connecting two halves of cerebral hemisphere of the cerebrum
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Describe 6 layers of grey matter comprising cerebral cortex
- Layer 1: almost no cell bodies
- Layer 2: inhibitory interneurons
- Layer 3: Excitatory interneurons
- Layer 4: Sensory signals project here
- Layer 5,6: pyrimidal cells (projection neurons) major output cells of the cortex
- non-pyrimidal cells involved in local processing
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List 4 cerebral cortices
- Temporal-auditory perception(primary auditory cortex)
- Frontal-voluntary movement (primary motor cortex)
- Parietal-sensory
- Occipital-visual processing center(visual cortex)
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Define sensory homunculus
"little man" maps which area of somatosensory cortex are devoted to particular regions of body
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Describe Graschwind model of language
- A theory of language processing
- Wernickes area
- primary visual cortex
- angular gyrus
- arcuate fasciculus
- primary cortex
- Brocas area
- primary auditory cortex
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Wenickes area (secondary auditory complex)
speech comprehension
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Brocas area
- language expression
- speaking and writing words
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Primary visual cortex
process vision
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angular gyrus
recognition of written words
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arcuate fasciculus
network of neurons connecting wernickes to brocas area
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primary motor cortex
control and excecution of voluntary movements
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primary auditory cortex
process sound
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If damage to wernickes
- Fluent nonsensical jargon (flows smoothly and quick)
- doesnt make sense but they are not aware of it
- possible neogism-making up new words
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If damage to brocas
- Difficulty speaking but they comprehend and understand what is being told to them.
- difficulty articulating syntax-grammatical rules/complete sentences
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Explain contralateral control
- one side of the brain controls other side of body
- in somatic sensory pathways:
- touch
- temperature
- proprioception
- pain
- 3 neuron series
- 1st order neurons triggered by receptor activation
- 2nd order neurons cross midline
- 3rd order neurons originate in thalamus(direct signal to appro. place)
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General functions of right hemisphere and language capabilities
- nonverbal and visual spatial
- language capabilities:
- understand meaning of a word
- comprehend vocab at 13 yr old level
- comprehend sentence structure at 5 yr old level
- give context to language
- govern emotional expression of language
- important visual spatial info
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General functions of left hemisphere
language and analytical function
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split brain patient
- Left hemisphere-language & analytical function
- Right hemisphere-nonverbal & visual spatial
- ask 1. what was patient asked to do?
- 2. which hemisphere activated?
- 3. think of contralateral control?
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