Anatomy exam 3 part 1
what are tactile receptors
(touch pressure vibration) - unencapsulated: free nerve endings, tactile disc, root hair plexus - encapsulated: tactile, bulbous, and pacinian corpuscle
dura mater
- 2 layers - periosteal: attaches skull - meningeal: covers brain and extends into vertebral canal - dural venous sinus: blood from vein empties
what are the brain ventricles
- CSF filled cavities - lateral: in cerebral hemisphere - third: in diencephalon - fourth: between pons and cerebellum - lateral and third communicate through interventricular foramen - third and fourth communicate to aqueduct - fourth communicates with cerebral canal
middle region of ear
- air filled cavity - inner tympanic membrane - auditory ossicles (MIS amplify sound waves) - opening to auditory tube: helps equalize pressure and connects inner ear to throat
what is receptive field?
- areas monitored by specific receptors - large or small - harder to localize stimuli in larger fields
temporal lobe
- auditory cortex - olfactory cortex - auditory association area
external region of ear
- auricle: elastic cartilage - external acoustic meatus: have ear wax glands and keeps out water - external tympanic membrane
subarachnoid space
- between arachnoid mater and pia mater - has CSF - cushions brain
what is the cerebrum?
- biggest part - gyrus: elevation increasing SA - sulcus: shallow depression - fissure: deep depression - longitudinal fissure separates R and L hemisphere - transverse fissure separates cerebellum and cerebrum - central sulcus separates frontal and parietal - parieto-occipital sulcus separates parietal and occipital - lateral sulcus - exterior surface is gray matter with many cell bodies - white matter has myelinated axons
protection and support of brain include
- bones of skull: brain is soft and needs extra protection - cranial meninges surround brain - CSF cushion and allows floating - blood brain barrier - rich blood supply
what are the 6 regions of the brain
- cerebrum - cerebellum - diencephalon (epithalamus, thalamus, hypothalamus) - mesencephalon - pons - medulla (makes link with brain and spinal cord)
vision
- detect by photoreceptors sensitive to photons - eyes have mostly structures for protection ex: eyelashes
what can chemoreceptors detect?
- detect change in oxygen levels - found in respiratory center of medulla oblongata, carotid bodies, aortic bodies
what are phasic receptors
- fast adapting - send signals at beginning and end - feeling dissipates over time
what are baroreceptors
- feel change of pressure - in bladder, lung, digestive tract, etc.
gustation
- gustatory cells in taste buds on dorsal surface - taste buds are epithelial cells w specialized gustatory cells responding to different stimuli - different taste buds - gustatory cells have microvilli that open up taste pores - taste info goes to the thalamus then to the gustatory cortex in the insula
insula
- gustatory cortex
vestibule
- has 2 membrane sacs: utricle and saccule (involved in gravitational pull and motion) - branching off is semicircular duct involved in rotational movement
anterior eye cavity of eye
- has anterior and posterior chambers - aqueous humor flows here - posterior has virtuous humor and keeps eye round
Cerebellar Punduncles
- how cerebellum and brain stem communicate - superior layer communicates mesencephalon, diencephalon, cerebrum - middle layer communicates pons - inferior layer communicate medulla oblongata
diencephalon
- in cerebellum - epithalamus: has pineal gland - thalamus: right and left divided by 3rd ventricle and all sensory info - hypothalamus: homeostasis
purkinje cells
- in cerebellum - molecular layer are dendrites - Purkinje layer are cell bodies - granular layer are axons and tightly packed neurons
choroid plexus
- in ventricles - bv network surrounded by ependymal cells that create CSF - take nutrients from blood and turn it to CSF - directionality due to ciliated movement of cells of CSF through ventricles - when CSF reaches the 4th ventricle it can leave through lateral and median aperture
cochlea
- involved in hearing - cells transduce sound waves to action potentials - have cochlear ducts between scala vestibuli and tympani
what are the two ways to classify general senses
- location on body - stimulus they respond to
brain stem
- mesencephalon (midbrain): movement of eyes, sight, sound, reflexes - pons: plays role in respiratory - medulla oblongata: connects brain and spinal cord (relay center)
what are proprioceptor
- monitor body position - integration with sensory information from inner ear conveys info of body position
olfaction
- nerve fibers in superior part of cavity which detect odor molecules - odor molecules bind receptors in nerve fibers - nerve fibers are specialized receptors, generate AP which travel up the cribriform plate, to the olfactory bulb, to the olfactory tract, and to the olfactory cortex
what purpose do eyelids have
- palpebral fissure between upper and lower palpebral - wash debris from eye - levator palpebral superioris helps open upper eyelid - orbicularis oculi closes - tarsal plates have tarsal glands that prevent sticking - orbital fat cushions eye
cerebral spinal fluid
- prevents contact of neural tissue with bones - provides support - transport nutrients to and waste away
frontal lobe
- primary motor cortex: (precentral gyrus) sends impulses down spine to muscle - premotor cortex: involved in motor movement - prefrontal cortex: thinking, problem solving, personality
parietal lobe
- primary somatosensory cortex (post central gyrus): consciously feel sensation - somatosensory association area: understanding of texture, size, and shape
what is the conjunctiva?
- protects and prevents debris from getting under eye - bulbar is anterior - palpebral lines the inner palpebrate
ciliary zonule
- pulls and controls lens shape - bends light - produces aqueous humor
blood brain barrier
- regulates substances between blood and brain tissue - made of capillary endothelial cells and astrocytes - nutrients in and CO2/waste out - no BBB in choroid plexus and hypothalamus
what are tonic receptors
- respond to every stimulus at same magnitude - all or none reaction - constant exposure
what are the layers of the skull
- scalp - epicranial aponeurosis - periosteum of cranium - cranium - meninges (separate soft tissue from bone) dura: toughest arachnoid: protects blood vessels pia: softest and attaches to brain (nourishes)
what is the cerebellum
- separated from brain due to 4th ventricle - 2nd largest - 2 hemispheres separated by vermis - anterior and posterior lobe separate by primary fissure - folia are folds in cerebellum - gray matter on surface - white matter is arbor vitae
folds of the dura mater
- support and limit brain movement - falx cerebri in cerebrum - falx cerebelli in cerebellum - tentorium along transverse cerebral tissue - crista galli: anchors brain, point of attachment for falx cerebri - sella turcica: enclosed by diaphragma sellae
inner region of ear
- vestibule apparatus - cochlea - membranous/bony labyrinth - space between labyrinths are filled with perilymph - endolymph is membranous labyrinth
occipital lobe
- visual association area: association of face with person - visual cortex
arachnoid mater
- weblike due to arachnoid tuberculae and anchors cerebral blood vessels)
cranial nerve 6
ABDUCES - abducts eye - motor
cranial nerve 11
ACCESSORY - motor - cranial and spinal root - innervates palate, pharynx, and larynx
cranial nerve 7
FACIAL - sensory and motor - carries sensory info from anterior 2/3 of tongue - motor controls face muscles, lacrimal gland, submandicular, and sublingual glands
cranial nerve 12
HYPOGLOSSAL - motor - goes to tongue
cranial nerve 3
OCULOMOTOR - motor function that helps move eye (not all extrinsic except superior oblique and lateral) - move upper eyelid, adjust amount of light, and lens
cranial nerve 1
OLFACTORY - most anterior - sensory function of smell
cranial nerve 2
OPTIC - sensory vision - only pair that comes together and separates in optic chiasm - simultaneous imaging
cranial nerve 5
TRIGEMINAL - motor and sensory - 3 branches - associated of all facial senses - ophthalmic and maxillary range are only sensory (upper teeth) - mandibular has both and innervates mastication
cranial nerve 4
TROCHLEAR - motor - only for superior oblique - innervated muscle goes through trochlea
cranial nerve 10
VAGUS - sensory and motor - goes to different regions - innervates respiratory, cardiovascular, and digestive organs - longest
cranial nerve 8
VESTIBULOCOCHLEAR - sensory - inner ear - info of equilibrium
what is receptor specificity
ability of sensory receptors to respond to one particular stimulus
what cells process visceral information
amacrine, bipolar, ganglion cells
what is the corpus callosum
bundle of axons connecting hemispheres - when combined with the anterior commissure they create commissural fibers
what are projection fibers?
connect brain stem to cerebral cortex
what are associated fibers?
connect regions of the same hemisphere ex: arcuate and longitudinal
arachnoid granulation
extensions where CSF reaches superior sagittal sinus
cranial nerve 9
glossopharyngeal sensory and motor swallowing, salivation, gag reflex, sensation form tongue and ear
chemoreceptors
monitor chemical composition of body fluid
iris
muscle that controls pupil
what is referred pain?
painful sensation from visceral organ is perceived as coming from another region
subdural space
potential space between dura mater and arachnoid mater
interoceptors
provide info of internal environment - in walls of digestive and respiratory system - detect oxygen levels and pressure - not aware
exteroceptors
provide information of external environment - usually superficial on skin and we are aware of it
lacrimal punctum
releases tears in lacrimal canaliculi, sac, and nasolacrimal duct
thermoreceptors
respond to change in temperature
nociceptors
respond to pain
mechanoreceptors
respond to physical distortion of cell membrane
proprioceptors
respond to stimuli in body position - we know where our limbs are
rods vs. cones
rod: black and white vision cones: color
sensation vs. perception
sensation: info arriving to CNS perception: conscious awareness of sensation
what are sensory receptors
specialized to respond to changes in environment - many receptors and stimuli specific
thermoreceptors vs. nociceptors
thermo: found in dermis, exist as free nerve ending, phasic noci: free nerve endings, large fields, tonic
what are the 3 eye layers
vascular - choroid (nourishes retina and cools eye) - ciliary body (controls lens shape) - iris fibrous - cornea - sclera retina - neural layer: senses light - pigmented layer: many melanocytes and prevents scattering
fornix
where lacrimal ducts open and tears are released
