Nervous II Flashcards
cerebrum
- conscious thought, intellectual functions
- has a large number of neurons needed for complex analytical and integrative functions
- cerebral cortex is executive suite of nervous system
functional areas of cerebrum
1) motor: voluntary
2) sensory: awareness of sensation
3) association: integrate and store info
cerebrum structure
- formed from telencephalon
- outer layer is cerebral cortex (grey matter)
- internal layer is white matter
- folds into elevated gyro
- shallow sulci
- deeper grooves called fissures
cerebral hemispheres
- left and right
- divided by longitudinal fissure
- connected by band of white matter for communication between them (corpus callous)
lobes of cerebrum
- frontal: voluntary motor function
- parietal: sensory function
- temporal: hearing and smell
- occipital: vision and visual memory
- insula: memory and taste
prefrontal cortex
- most complicated
- intellect, learning, personality, emotions, social interactions
speech associations areas
- brocas area
- wernickes area
- connected by group of nerve fibres called arcuate fasiculus
broas area
- left frontal lobe
- language production
wernickes area
- left temporal lobe
- processing of words heard
diencephalon
- 3 paired structures
- thalamus
- hypothalamus
- epithalamus
encloses 3rd ventricle
thalamus
- oval masses of grey matter on either side of 3rd ventricle
- sensory relay station
- where impulses from senses (except olfaction) converge and synapse
- sorts and relays info to be sent to cerebral cortex
hypothalamus
- for wall of 3rd ventricle
- thin, stalk-like infundibulum extends inferiorly from hypothalamus to attach to pituitary
- controls homeostasis
- autonomic NS, endocrine NS, body temp, emotional behaviour, food and water intake, sleep-wake cycles
epithalamus
- very small
- forms roof of 3rd ventricle
- houses pineal gland
pineal gland
- secrets melatonin
- melatonin is a hormone that helps regulated day-night (circadian rhythm) with hypothalamus
midbrain
visual and auditory reflex centres
brain stem
- pons
- medulla oblongata
pons
- relays info from cerebrum to cerebellum
- helos respiration
medulla oblongata
- sensory and visceral control centres
- pains, heart rate, blood vessel diameter, respiration, vomiting, coughing
limbic system
- where cerebral cortex meets subcortical structures
- direct impact on endocrine system
- learning, motivation, memory, emotion
- associated with brains pleasure centre
hypothalamus, hippocampus, and amygdala
hippocampus
- paired, curves, under the middle of temporal lobe
- learning
- spatial orientation, navigation, spatial memory
- short and long term memory
- emotional responses to stimuli
amygdala
- almond-shaped nuclei deep in temporal lobe at end of hippocampus
- memory
interprets emotions and moods (fear, happiness, pleasure anxiety, sadness)
psychopaths and amygdala
- have ~20% reduced size and function
science of addiction
-
cerebellum
- 11% of brain mass
- “little brain”
- input from cortex, brain stem, and sensory receptors
- allows smooth and coordinated movements
- maintains balance and posture
cerebellum hemispheres
- hemispheres connected by vermis
- folia are transversely oriented gyri
- each hemisphere has 3 lobes
- arbor vitae is tree pattern of cerebellar white matter
- encases 4th ventricle
spinal cord
- provides a vital link between brain and rest of body
- attached to spinal nerves
2 important functions of spinal cord
1) pathway for sensory and motor impulses
2) responsible for reflexes (quickest reactions to a stimulus)
spinal cord anatomy
- grey matter in center
- white matter surrounds grey
- all neurons that have cell body in grey matter are multipolar
- right and left horns connected by thin band of grey matter (grey commissure)
- central canal is hollow with CSF
cervical enlargement
- in inferior cervical part of spinal cord
- innervates upper limbs
lumbosacral enlargement
- extends through lumbar and sacral parts of spina cord
- innervates lower limbs
conus medullaris
- tapering inferior end of spinal cord
- official end of spinal cord proper
vertebral canal
- spinal cord is shorter than vertebral canal
- runs 2/3 of spinal column length
- ends between L1 & L2
cauda equina
- inferior to conus medullaris
- groups of axons projecting from spinal cord
filum terminale
- within cauda equina
- thin strand of Pia mater
- helps anchor conus medullaris to coccyx
lumbar puncture
- spinal tap
- CSF removed from subarachnoid to diagnose meningitis
- between L3 and L4 because its past conus medullaris
- patient bent to make space
- similar to epidural
dermatomes
- area of skin innervated by cutaneous branch of a single spinal nerve
- every spinal nerve innervates a dermatome (except C1)
- adjacent dermatomes overlap and not clearly separated
- overlap in trunk more than limbs
how to determine and spinal cord or nerve injury
determine position by examining the dermatomes affected
important nerves
- cranial and spinal nerves are peripheral NS
- all nerves emerge from brain or spinal cord
cranial nerves
- 12 pair
- 2 at forebrain and rest with brain stem
- mostly mixed
- 2 pair purely sensory
- “oh once one takes the anatomy final very good vacations are heavenly”
CN I
- olfactory nerve
- olfaction=sensory nerve (sense of smell)
- fibres pass through cribriform plate in skull to embed in nasal cavity
CN II
- optic nerve
- vision= sensory nerve (sense of vision)
- criss-cross before entering brain (optic chiasm)
- sends half to on side of brain and half to the other
CN III
- oculomotor nerve
- motor nerve
- 3 rectus: eye muscles, inferior oblique, and elevator palpebrae superioris (superior, medial, inferior)
- controls pupil constriction
CN IV
trochlear nerve
- motor nerve
- innervates superior oblique muscle which runs through trochlea
CN V
- trigeminal nerve
- sensory & motor nerve
- 3 branches: (V1, V2, V3) innervate sensory fibers to face
- motor fibers to chewing muscles
V1, V2, V3
- V1: ophthalmic branch
- V2: maxillary branch
- V3: mandibular branch
CN VI
- abducens nerve
- motor nerve
- innervates lateral rectus muscles
- abducts eye
CN VII
- facial nerve
- sensory & motor nerve
- sense of taste for anterior 2/3 of tongue
- 5 branches control muscles of facial expression
5 branches of facial nerve
- temporal
- zygomatic
- buccal
- mandibular
- cervical
CN VIII
- vestibulocochlear nerve
- sensory & minute motor
- mostly sensory for hearing and equilibrium
- 2 branches for balance and sound
CN IX
- glossopharyngeal nerve
- sensory & motor
- innervates posterior 1/3 of tongue for taste
- tongue and pharynx muscles for swallowing
CN X
- vagus nerve
- sensory & motor
- visceral sensory info from pharynx, larynx, carotid bodies, heart, lungs, and most abdominal organs
- muscles of pharynx and larynx
CN XI
- accessory nerve
- motor nerve
- innervates trapezius and sternocleidomastoid
CN XII
- hypoglossal nerve
- motor nerve
- innervates intrinsic and extrinsic tongue muscles
- in medially from vagus nerve
spinal nerves
- generally name in groups or plexuses after their vertebral location
- plexuses are responsible for coordinated movement of a body region
cervical plexus
- on lateral sides of neck
- innervates head, neck, and shoulders
- phrenic nerve is important branch of it
phrenic nerve
- to innervate diaphragm
- damage prevents you from breathing
- travels down neck and through thoraces cavity to innervate diaphragm and allows you to breathe
brachial plexus
- innervates upper limbs
- extends laterally below cervical plexus, under clavicle, through axillary region and down the arm
- important branches: lateral radial nerve, medial ulnar nerve, central median nerve
- damage to median nerve causes carpal tunnel
lumbar plexus
- innervates lower limbs
- extends laterally from lumbar vertebrae, over and through os coxae, and down anterior surface of leg
- important branch is femoral nerve
femoral nerve
- control anterior thigh muscles
sacral plexus
- innervates buttocks, genitals, posterior thigh, leg, and foot
- emerges form sacral foramen and runs down posterior length of leg
- important branch is sciatic nerve
sciatic nerve
- largest nerve in body
- controls part of the thigh, leg, and foot
