Unit 1 Flashcards
Cells that make up nervous system?
Neurons and glia
Neurons
Send electrical signals to targets through body
Dendrites
Branched extensions that receive signals from other neurons. , main receptive or input regions., have receptor proteins
Axon
Typically transmits signals longer extension that
Transmits signals to other cells
Axon hillock
General area where action potentials the generated
Initial segment of axon
Usually the site where the “all or none”
Action potential is officially induced
Where are soma located?
Most located in CNS, protected by bones
Nissl bodies
Chromatophilic substances, where proteins manufactured, easily stained
Where are graded potentials formed?
Dendrites, formed here by specific stimuli, bringing positive charged ions like Na+
How does axon hillock work?
If enough positive charge enters via graded potential, triggers the action potential here, which moves down axon to targets
Axon terminals
Sites where axon connect to another cell
Synapse
Junction between branched ends of an axon and another cell, where there is a space/ cleft
Synaptic terminal
To continue signal transmission, specialized end of axon releases neurotransmitters using vesicle exocytosis
Post synaptic cell can be:
Neuron, muscle, gland
Glia
Support cells for neurons, greatly outnumber neurons
Ependymal cells
Line the central cavities throughout brain and spinal card
Ciliated ependymal
Circulate cere’brospinal fluid, plays role in immunity, protection, cushioning, nourishment of CNS
Oligodendrocytes
Produce myelin sheaths in tracts in the CNS, to speed up signal transmission
- single oligodendrocyle can bundle multiple axons
Formation of myelin sheath in PNS
Formed by Schwann cells along motor neurons, functionally similar to oligodendrocyles in CNS
Schwann cells typically wrap around a
Single axon at a time
Function of myelin sheath
Increase speed of signaling, insulate axons and makes “gaps” called mode of ranvier between the glia
Purpose of node of rangier
Decrease amount of membrane that needs to depolarize during an action potential
- electrical signal jumps from gap to gap “saltatory conduction” speeds up signaling
Satellite cells
Support cell bodies in PNS, linking neurons to capillaries for nutrients
- provide buffer zone between circulatory system and PNS
Location of satellite cells
Unipolar neuron and ganglia of PNS
Structures of neurons
Multi, bi, and uni
Information processing neuron path stages
Sensory inputs, integration, and motor
① sensory input
Sensory neurons will detect stimuli ( external/ internal) and transmit a signal towards CNS
② Integration
Signal relayed to interneurons in brain or spinal cord for analysis and /or processing, so an appropriate response can be selected
③ motor response
Processed signal is then relayed to motor neurons to trigger needed response in muscles, gland, organs
CNS
Interneurons that integrate and process signals, and then select an appropriate response
PNS
Carries info from sensory neurons towards the CNS for processing and relays processed signal from CNS to motor neurons to appropriate response
Afferent neurons
Transmit sensory signals towards CNS
Sensory receptors
Generate graded protential> action potential in response to either external/internal stimuli
Efferent neurons
Transmit motor responses away from CNS
- signals sent to targets, that will produce action needed for response
Many nerves have both…
Efferent and afferent
Spinal nerves form from…
Dorsal and ventral root
Tracts
Ascending/descending neurons w/in spinal cord
- form synapses with either sensory/ motor neurons
Sensory neurons
Axons that project to gray matter in spinal card (afferent )
Motor neurons
Cell bodies that project their axons away from spinal card (efferent)
What neurons make up spinal cord?
Sensing and motor
Spinal nerve connective tissue layers,
Myelin sheath, endoneurium. , perineurium, epineerium
Axons protected in…
Myelin
Individual axon wrapped in…
Endoneurium
Wrap groups ot axons in fascicles
Perineurium
Surround all fascicles to form nerve
Epineurium
Blood vessels
Present to form interface w/ glia to get needed nutrients to neurons
Fibroblasts
Production of collagen fibers
Olfactory nerve (1)
Sensory nerve, targets smell
Run from nasal mucosa to synapse w/ olfactory bulbs
Optic (2)
Sensory, defect visual input from eyes
Optic chasm
Optic chiasma
Point in brain where optic nerve crosses
Oculomotor ( 3)
Motor, move muscles in eyes
Somatic (voluntary)movement:tracking, squinting
Parasympathetic (automatic) motion, focusing our lens during pupil dilation /contraction
- 4 out of 6 extrinsic muscle for voluntary movement
Trochlear (4)
Motor, rotation in eyes
Regulate somatic(voluntary) movement
Damage can result in double vision
I out of 6 extrinsic muscles
Trigeminal(5)
Mixed, largest cranial nerve branch from pons
Sensory sent to face, detect stimuli( touch, temp., pain)
Motor sent to jaw to control chewing muscles
Ophthalmic, maxillary, mandibular.
3 branches of trigeminal
VI: ophthalmic: skin,nasal (sensory)
V2: maxillary: upper teeth/mouth(sensory)
V3: mandibular: lower teeth/ mouth(sensory), cheek muscles for chewing (motor)
Abducens(6)
Motor for lateral (sideways) motion of eyes
Connect to inferior (lower) pons
I out of 6 muscles
Facial (7)
Mixed,
Sensory: taste buds on anterior( 2/3) of tongue
Motor: face expressions., sent to autonomic parasympathetic muscle and glands for tear ducts and ( 2/3) saliva glands
Vestibulocochlear (8)
Sensory, detect signals from ears
Detect sound, maintain equilibrium/balance
Glossopharyngeal (9)
Mixed, innovates tongue and pharynx
Sensory: connect taste buds (1/3) posterior tongue
Motor: control voluntary (somatic) muscles for swallowing
Parasympathetic (autonomic) system control 1/3 salivary gland
Vagus (10)
Mixed, descends into abdomen
- involuntary (parasympathetic)., sensory: sensory input “gag reflex”, organ physiology, motor: connect organs “vest and digest”
- voluntary (somatic)- motor: connect pharyngeal muscles used during voluntary swallowing
Spinal accessory (11)
Motor, movement of head, shoulder, neck
Sent to trapezius and sternocleidomastoid, that control movement
Formed from rootless of spinal
Hypoglossal(12)
Motor, innovates muscles of tongue
Synapse w/extrinsic and intrinsic
Control voluntary motions for food manipulation and movement for speech
PNS general senses
Touch, pressure, temperature, pain
Usually in skin or internal tissues
PNS special senses
Vision, hearing/ equilibrium, smell, taste
Usually in head and specialized sensory organs
Most of eye enclosed and protected by…
Fat cushion and bony orbit
Lubricating glands n eyelids
Tarsal glands: stop eyelid sticking
Ciliary glands: between hair follicles
Conjunctiva (eye)
Transparent mucous membrane that produces a fabricating mucous secretion
- keep eye from drying out
Palpebral conjunctiva(eye)
Lines eyelid
Bulbar conjunctiva (eye)
Lines eyeball
Conjunctival sac (eye)
“Pocket” between 2 layers
Lacrimal apparatus (eye)
Produce tears to moisten eye, consists of lacrimal glands and ducts
Lacrimal gland (eye)
Produce secretions, tears that move
- move out ducts into conjunctiva
-Flow to lacrimal puncta openings
-Enter lacrimal canaliculi
- collect in lacrimal sac
- go to nasolacrimal duct / nasal cavity
Extrinsic muscles: move eye in orbit
6 eye muscles which are controlled via cranial nerves
4 rectic muscles (eye) extrinsic
Eye movements
Superior, inferior, lateral, medial
2 oblique muscles (eye extrinsic muscles)
Move eye in vertical plane and rotate eyeball
Superior and inferior oblique muscles-help to correct drift when we need to move eye ↑ and ↓
Superior oblique muscle takes a path…
Through trochlea
Eyeball
Slightly irregular, hollow sphere w/ 3 layered wall
- fibrous, vascular, inner layers
Eye internal cavity
Filled w/ fluids called “humors” that maintain shape
Eye lens
Adjustable focusing apparatus needed for vision
Fibrous layer (eye)
Outermost layer, which has sclera and cornea
Dense vascularized connective tissue
Sclera (fibrous eye layer)
Posterior portion(83%)
- white / opaque “white of eye”
- protect and shape eyeball
- anchor site for extrinsic muscle
- site where optic nerve enters, continuous w/ dura mater
Cornea (fibrous eye layer)
Anterior portion (17%)
-transparent “window” for light
- helps bend light towards lens
- large regenerative capacity
-2 epithelia layers
- pain receptors contribute to blinkingandtears
2 epithelia layers cover cornea
External: protects from abrasion
Deep:Na+ pumps to clarify cornea
Vascular layer of eye
Middle layer, which has choroid, ciliary body, iris
Choroid (vascular layer)
Posterior area
- supplies blood to all layers
- opening for optic nerve
- brown pigment absorbs scattered light to avoid confusion
Ciliary body (vascular layer of eye)
Ciliary body:anterior layer, thickening tissue circles lens
Ciliary muscles: interlacing smooth muscles that control lens shape
Ciliary processes: secrete fluid that fills anterior cornea/ lens
zones. ligaments connect proce ssesto lens,help
Iris (vascular layer eye)
Colored part of eye
Between cornea/lens
2 smooth muscle layers
Pupil and diaphragm
Pupil
Round central opening that allows light to enter eye
Diaphragm
Reflexes cause pupil to open/close to control light entry by varying pupil size
Retina (eyeball layer 3)
Pigmented layer, inner neural layer, optic disc
3 neuron types: photoreceptor, bipolar,ganglion
Rods and cones
Macula luted, fovea centralis
Outer pigmented layer of retina
One “single cell thick”
Lines next to choroid
Extends anteriorly, cover ciliary body and iris
Function: absorb light, phagocytizes photoreceptor fragments, store vitamin A
Inner neural layer of retina
Thicker transparent layer
Extends to margin of ciliary body
“Stops short” at ora errata
Optic disc
Site where optic nerve leaves retina
-No photoreceptor cells
- we have blind spot in reception
Photoreceptors (retina)
Change shape W/ light
Terns off inhibitory neurotransmitter
Allows next cells to depolarize
Bipolar cells (retina)
Depolarize, when allowed
Pass stimulatory neurotransmitter to gangland cells
Ganglion cells (retina)
Depolarize and send AP ↓ axons to optic nerve
Rods (retina)
Detect dim light
More sensitive than cones but. have 1 type of visual pigment, only perceive shades of gray
Peripheral vision receptors
Coverage onto many ganglia causing fuzzy mages
Cones (retina)
Vision receptors for bright light
Red, blue, green
Non-converging pathways w/ detail
High-resolution color vision
Macula lutea (retina)
Posterior pole, lateral to blind spot that contains mostly cones
Fovea centralis (retina)
Tiny pit n macula luted that contains all cones, best visual acuity, where images need to be focused on to view critically
3 major areas of ear
① external ear: hearing only
② middle ear (tympanic cavity): hearing only
③ internal ear: hearing and equilibrium
Receptors for sound and balance respond to…
Separate stimuli and are activated independently
External outer ear
Move sound waves into ear canal and drum
- Auricle (pinna)
- External acoustic meatus (ear canal /auditory canal)
- tympanic membrane(ear drum)
Auricle (pinna) - external ear
Structure surrounding ear canal that functions to funnel sound waves into ear canal
Helix: cartilaginous rim
Lobule: fleshy “earlobe”
External acoustic meatus( ear canal/ auditory canal) - external ear
Short, curved tube lined w/ skin, hairs, sebaceous glands, and earwax glands
- transmits sound waves to ear drum
Tympanic membrane (ear drum) -external ear
Vibrates in response to sound waves
Middle ear ( tympanic cavity)
Transfer vibrations from ear drum to inner ear
- skin covers outer surface
- thin/ translucent connective tissue
- mucosa inner surface
- pharyngotympanic (auditory tube)
- auditory ossicles
- synovial joint, ossicle relay, tensor+ stapedius
Skin- covered outer surface -middle ear
Receives sound waves via external environment
Thin/translucent connective issue- middle ear
Vibrates in response to sound
Mucosa inner surface -middle ear
Transfers the vibration energy to connected bones of middle ear
Pharyngotympanic (auditory) tube -middle ear
Connects middle ear to nasopharynx
- usually flattened/closed take, yawning or swallowing opens to equalize pressure in middle ear w/ external air pressure
Otitis media - middle ear inflammation
Common w/ short or horizontal auditory tubes.
- inflammation lead to bulging ear drum, pain, balance issu es, hearing loss
- treated w/ antibiotics
Auditory ossicles: middle ear
3 small bones in tympanic cavity
① malleus: hammer joined to eardrum
② incus:anvil intermediary
③stapes: stirrup fits into oval window
- vibration transferred through bones to oval window and inner ear
What does round window do?(middle ear )
- Vibrations cause oval window to push inward into inner ear
- fluid in inner ear gets displaced by vibrational pressure
- Round window pushes outward into middle ear
- allows fluid movement in inner ear and prevents pressure buildup
Synovial joints - middle ear
Het malleus articulate w/ incus, which articulates then w/ stapes (suspended by ligaments)
Ossicle relay - middle ear
Transmits vibration of the eardrum to oval window
Tensor tympani + stapedius muscles - middle ear
Contract reflexively in response to loud sound to prevent damage to hearing receptors
Internal (inner) ear
Fluid-filled “labyrinth” w/ sensory receptor neurons
- bony labyrinth
- membranous labyrinth
- saccule and utricle
-Maculae and sterocillia
- 3 canals
- cristae
- cochlea
- spiral organ
Bony labyrinth(internal ear)
Tortuous channels and cavities that warm through the bone temporal bone, behind eye socket
- filled w perilymph fluid
- similar to CSF
- 3 regions: vestibule, semicircular,cochlea
Membranous labyrinth (internal car)
Membrane sacs and ducts contained In bony labyrinth
- filled w/ endolymph fluid
- k+ - rich, w/ other ions
3 regions bony labyrinth (internal ear)
- Vestibule: equilibrium/gravity
- semicircular canals: equilibriums/angular
- cochlea: hearing
Vestibule (inner ear)
Monitors gravity /equilibrium
Egg shaped chamber, lateral side connected to oval window
- saccule and utricle
Saccule and utricle (vestibule) inner ear
Inside bony labyrinth vestibule, “sacs” of membranous labyrinth:
-Saccule: continuous w/ cochlea
-Utricle: goes to semicircular canal
- house maculae
What do saccule and utricle house? (Internal earl
House regions called maculae, which respond to pull of gravity and head position
Maculae (internal ear) equilibrium reception
Sensory receptor organs which monitor “static equilibrium”
- position of head in space, play key role in control of posture
- respond to linear acceleration forces, but not rotation
- stereacilia (hairs)
Stereo cilia (hairs) internal ear
Embed in otolith membrane, studded w/ otolith stones that ↑ the membranes weight and inertia
3 canal’s “3-planes of space” (internal ear)
Detect angular rotation
- anterior, lateral, posterior: membrane ducts float inside
- anterior/posterior ducts: right angles
- ampulla; duct w/equilibrium receptor region called crista ampules ( movement of head)
Cristae ampullaris ( internal ear)
Angular rotation
- both support and hair cells that extend into gel-mass called ampullary cupola
- excited by acceleration and deceleration of head which comes w/ rotational(angular) movements like “twirling” of body
Are semicircular canals in all 3 planes of space? (Internal ear)
Yes, cristae can detect “swirls” of all rotational movements
Cochlea (internal ear)
“snail” structure that detects sound, bony chamber
-Extends from vestibule, coils around modiales, bony pillar, end apex at round window
- cochlear duct which has spiral organ that detects sound
3 fluid filled “scale” cochlea (internal car)
Transmits vibration and detects sound
① scala vestibule
② scala tympani
③ perilymph chambers
- spiral organs
- scala media
- vestibular membrane
- outer / inner hair cells
Spiral organ - cochlea (internal ear)
Coils along w/ cochlear duct ( scale media)
- contains sensory hairs that detect sound related vibrations
① scala vestibule e -cochlea (internal earl
Abuts oval window, contains perilymph
② scala tympani -cochlea (internal ear)
Terminates at the round window; contains peri lymph
③ perilymph chambers - cochlea( internal ear )
Continuous w/ each other and bony labyrinth and merge in the helicotrema, at the apex
scala media - cochlear ( internal ear)
Cochlear duct
Houses spiral organs; contalhs endolymph( made by stria vascularis
Vestibular membrane - cochlear( internal ear)
“Roof” of cochlear duct separating scale media from scala vestibuli
What is cochlear duct “roof” made of? ( internal ear)
Made of bony spiral lamina and basilar membrane, which support spiral organ
- spiral ganglia make cochlear branch of cnviii infiltrate “floor”
What does spiral organ contain? (Internal ear)
Har cells, that arrange between tectorial membrane and basilar membrane
Inner/ outer hair cells
Inner hair cells - spiral organ(internal ear)
(One row): detect sound vibrations coming through the basilar membrane
-
How do inner har cells work? (Internal ear)
Sterocilia “tips” are enmeshed in tectorial membrane and pivot while basilar membrane vibrates, causing depolarization that is then relayed to cochlear nerve
Outer hair cells - spiral organ (internal ear)
(3 rows): can contract and stretch, which change the stiffness of basilar membrane
2 purposes of outer hair cells (internal ear )
① help “fine-tune” inner hair cells by amplifying the notion of basilar membrane
② protect inner hair cells from loud noises by ↓ motion of basilar membrane
What are the main functional classes of neurons and where are they usually found?
Sensory (afferent) neuron: found in PNS transmit sensory input to C NS
Interneurons : found in CNS process and relay information
Motor (efferent) neurons: founded PNS carry commands from the scenes to muscles and glands
What are main structural classes of neurons where are they usually found?
Multipolar neurons: most common found in CNS and motor neurons of PNS
Bipolar neurons : found in special senses
Unipolar neural : found in sensory neurons of PNS
What are different types of glia and what are their roles?
Astrocytes(CNS): support neurons, maintain blood brain barrier
Microglia ( CNS ): act as immune cells, remove debris
Oligodendrocytes (CNS): produce Milan for CNS axons
Ependymal cells (CNS): help produce cerebral spinal fluid
Schwann cells (PNS): produce Milan for PNS axons
Satellite cells (PNS): supporting neuron cell bodies in ganglia
Can a presynaptic cell be a neuron muscle or gland cell?
Usually a neuron
Which cranial nerves have autonomic parasympathetic functions
Ocular motor
Facial
Glossopharyngeal
Vagus
Which cranial nerves serve structures of the eyes
Optic
Oculomator
Frochlear
Abdomens
Are blood vessels inside or outside of fascicle?
Outside
Blood vessel supplying nerves are called Vasso Navarro
What is the space that spinal nerves passed through in the vertebral column?
Intervertebral for Amina
Do spinal nerves have motor axon sensory axons or both
Both spinal nerves are mixed nerves containing both sensory and water fibers
What is conjunctiva
Transparent membrane covering sclera and inner eyelid
What is conjunctival sac?
Space between eyelid and eyeball were tears collected
Path tears take to move from lacrimal gland to nasal cavity
Lacrimal gland, lacrimal punch, lacrimal canaliculi, lacrimal sac, nasolacnimal duct, nasal cavity
Which cranial nerves connect to which extrinsic muscles
Ocular motor: superior rictus, inferior rictus, medial and inferior
- trochlear: superior oblique
- abdomens: lateral rictus
What special loop does superior oblique muscle pass through?
Trochlear
Does the cornea help focus light?
Yes
What colors are most commonly affected with color blindness?
Red and green
What causes a pressure wave?
. Vibration
What does wavelength of a pressure wave correspond to?
Frequency
What does amplitude of a pressure wave corresponding?
Loudness
Function of oval window
Transferred vibrations into cochlea
Function of round window
Relief pressure in the cochlea
