-
Somatic motor system controls:
-skeletal muscles
-
ANS controls:
-visceral muslces
-
Peripheral Nervous Systemn consists of:
-Peripheral nerves and Ganglion
-
Afferent sensory system (PNS):
-General and special senses coming into CNS
-
Efferent sensory system (PNS):
- -Somatic nervous system controlling SKELETAL muscles (Voluntary)
- -Autonomic nervous system controlling smooth muscles, cardiac muscles, glands (Involuntary)
-
The role of the Autonomic Nervous System:
- 1.) Operates without conscious sontrol via reflex centers in spinal cord and brainstem controlled by hypothalamus
- 2.) Regulated by higher brain centers that affect the hypothalamus
- -Limbic system, thatlamus, cerebral cortev
- 3.) Coordinates processess that maintain homeostasis (negative feedback)
- -Cardiovascular, respiratory, digestive, urinary, reproductive, etc.
-
Hypothalamus=_____
- headquarters
- -ANS responses and endocrine systems
-
The ANS is divided into two divisions that jointly control most visceral responses:
- 1.) Sympathetic division (Fight or flight)
- -expenditure of energy
- -Dominant under emotional stress
- 2.) Parasympatheic division (rest and digest)
- -Conserve and restore body energy, rest and recovery
- -Dominant control during rest
-
What is a maximum response?
- Everything for a sympathetic response kicks in and activates fight or flight response that occurs simultaneous
- ex. bear
-
Sympathetic response includes:
- -heart rate increases (above 100)
- -respiratory rate increases
- -pupils dilate (to be more aware of surroundings)
- -digestion slows down
- -heat production increases
- -Blood vessels: to heart=dialte
- *to skeletal muscles=dilate
- *to GI tract=constrict
- *to brain=dilate
- *to kidneys=constrict
- -respiratory muslces relax (relaxes trachea to get more air)
- **full body response
-
Parasympathetic response includes:
- -heart rate decreases (below 100)
- -respiratory rate decreases
- -digestion increases
- -Blood flow: to GI tract increases
- *to kidneys increases
- *to sexual organs increases
- -respiratory muscles constrict
- **Localized
-
Dual innervation:
When something is innervated by sympathetic and parasympathetic neurons
-
Heart:
- -Sympathetic increases heart rate
- -Parasympathetic decreases heart rate
-
Pupils:
- -Sympathetic dilates pupils
- -Parasympathetic constricts pupils
-
Digestive Tract:
- -Sympathetic decreases motility and secretions
- -Parasympathetic increases motility and secretions
-
Bronchioles:
- -Sympathetic dilates airways
- -Parasympathetic constricts airways
- *bronchioles lead to alveoli in respiratory tract
-
Norepinephrine gives a __________ response
sympathetic
-
Effectors with sympathetic input only:
- -sweat glands (increased secretions)
- -arrector pili muscles
- -blood vessels of skin, skeletal muscles, heart, lungs, brain (dilation)
- -blood vessels of digestive viscera and kidney (constriction)
-
Effectors with parasympathetic input only:
-Lacrimal glands (increased secretion)
-
ANS is straight forward - always sends ___ neurons out
2
-
Structure of ANS: (Efferent pathway is 2 neuron pathway)
- 1.) motor neurons in CNS send axons (preganglionic) to synapse on motor neuronsi n autonomic ganglia in PNS
- 2.) motor neurons in sutonomic ganglia (ganglionic cells) send axons (postganglionic axons) to synapse on effector
-
Structure of sympathetic:(Thoraco-lumbar division)
- Preganglionic cell body in lateral horn of spinal cord segments (T1-L2)
- Preganglionic axon typically shorter
- Ganglion typically close to CNS
- -sympathetic chain ganglia
- -collateral ganglia
- -adrenal medulla
-
Structure of parasympathetic: (Cranio-sacral division)
- -Preganglionic cell body in nuclei of CN III, VII, IX, X, and lateral horn of spinal cord segments S2, S3, S4
- -Preganglionic axon typically longer
- -Ganglion typically near or in effector organ, so postganglionic axon is shorter
-
Organization and anatomy of the sympathetic division:
- 1.) SC segments T1-L2- ventral roots contain preganglionic axons
- 2.) White ramus branch from ventral root carries axons to sympathetic chain ganglia
- 3.) Some axons synapse on cells of chain ganglia (closest to CNS--line up along SC)
- 4.) Some axons pass through going to collateral ganglia and adrenal medulla
-
Sympathetic division: Sympathetic chain ganglia (Thoraco-lumbar)
- -2 chains of ganglia- one on each side of the vertebral column (Right and Left)
- -Cervical chain ganglia are fused into superior, middle and inferior
- -Innervate head, body wall, limbs, and viscera of thoracic cavity (heart, lungs)
- **most synapse at collateral chain ganglia
-
Sympathetic division: Collateral ganglia (Thoraco-lumbar)
- -Located close to large abdominal arteries
- -3 types of collateral ganglia and corresponds with abdominal organ: Celiac, superior mesenteric, inferior mesenteric ganglia
- -Preganglionic fibers in anterior root, white ramus, then pass through chain ganglia and form splanchnic nerves to reach collateral ganglia
- -Innervate abdominal and pelvic viscera (Sympathetic activation decreases blood flow and releases stored energy molecules)
-
Sympathetic division: Adrenal medulla (Thoraco-lumbar/secretes epi and norepi)
- -Central portion of the adrenal gland
- -Preganglionic fibers in anterior root, white ramus, then pass through chain ganglia and splanchnic nerve to superior mesenteric ganglia, pass through to reach adrenal gland (before there's a synapse)
- -Postganglionic cells in adrenal medulla are modified neurons that secrete into blood rather than onto effector
-
Parasympathetic division: (Cranio-sacral)
- 1. Preganglionic neurons in the brainstem and sacral segments of SC
- 2. Ganglionic neurons in peripheral ganglia located near or within target organs
- 3. Effects produced by the parasympathetic division include relaxation, food processing, energy absorption
-
SC segments S2, S3, S4:
- -Pelvic nerves carry preganglionic axons to parasympathetic intramural ganglia located in wall of viscera in inferior portion of abdominal pelvic cavity
- -Short postganglionic axon innervate effectors (LONG pre-ganglionic)
-
Cranial nerve III: (Oculomotor)
-Parasympathetic control of pupil and lens
-
Cranial nerve VII: (Facial)
-lacrimal and salivary glands
-
Cranial nerve IX: (Glossopharyngeal)
-salivary glands
-
Cranial nerve X: (Vagus nerve)
- -Carries 75% of all parasympathetic output
- -Parasympathetic control of heart, lungs, digestive tract and all other thoracic and abdominal viscera, except most inferior portions
- **heart to intestines=vagus
-
Can't survive with damage to your __________ nerve
Vagus
-
Autonomic Activation:
-Sympathetic and parasympathetic divisions are activated by different stimuli
-
Sympathetic innervation is ____________ body
throughout
-
Each preganglionic axon branches to synapse onto ____ or more ganglionic cells (symapthetic)
24
-
Adrenal medulla releases _____________ and norepinephrine into blood stream, affecting tissues not innervated by ANS
epinephrine
-
Parasympathetic activation has __________ effect
localized
-
Parasympathetic activation innervation is limited to _______ and __________, doesn't innervate body wall, skin
head, viscera
-
Parasympathetic activation: each preganglionic axon branches to synapse onto only ___-____ ganglionic cells
6-8
-
Parasympathetic activation: postganglionic axons generally fo to a ______ effector
single
-
Synapse of preganglionic axon onto cell in autonomic ganglion: Neurotransmitter is ____ in both symp. and parasymp ganglia
Ach (always)
-
Synapse of postganglionic axon to effector:
- -All parasympathetic postganglionic axons release Ach onto effectors
- -Sympathetic postganglionic axons to dual innervated viscera release norepinephrine onto effectors
-
Response always depends on ______
neurotransmitter
-
Postsynaptic _________ properties determines effect of neuroransmitter on postsynaptic cell
resceptor
-
Many neurotransmitters have more than one type of ____ synaptic receptor
post
-
Nicotinic cholinergic receptors:
- -Skeletal muscles, autonomic ganglia
- -ALWAYS excitatory (can be chemically gated)
- **at every ganglion
-
Muscarinic cholinergic receptors:
- -excitatory OR inhibitory (depends on organ it's a receptor for)
- -Visceral muscles, cardiac muscles, CNS
-
Alpha Adrenergic receptors:
- -Excitatory effect on smooth muscles of blood vessels of skin & viscera, causes constriction
- **Alpha blockers-reduce hypertension
-
Beta adrenergic receptors:
- -Beta 1: excitatory on cardiac muscle
- **Beta blockers reduce heart rate
- -Beta 2: inhibitory on smooth muscles of respiratory tract, causes relaxation
-
Synapse of preganglionic axon onto cell in autonomic ganglion:
- -Neurotransmitter is ACh
- -Postsynaptic receptor is ALWAYS nicotinic cholinergic (excitiatory)
- -same in sympathetic and parasympathetic ganglia
-
Synapse of postganglionic axon to effector:
-different neurotransmitter and postsynaptic receptors depending on synapse
-
Dually innervated = what hormone?
norepinephrine
-
Sympathetic postganglionic axons to:
- -viscera that have dual innervation: release norepinephrine onto effectors (adrenergic synapses)
- -viscera that receive ONLY sympathetic input: release NE or ACh or NO onto effectors (blood vessels to skin)
-
Sympathetic postganglionic cells of the adrenal medulla:
-release epinephrine and (some) NE into the blood stream (act as hormones)
-
Sympathetic postganglionic NE axons end in branching network with multiple ___________ filled with neurotransmitters
-
Removal of NE after release is slower because:
- -Can't break down quickly like ACh
- -Reuptake and reuse
- -Breakdown by monoamine oxidase (MAO) and catechol-O-methyltransferase (COMT) in surrounding tissue and in liver
-
MAO breaks down _______
norepinephrine
-
Alpha adrenergic receptors:
- -Excitatory effect on smooth muscles of blood vessels of skin and viscera, causes constriction
- **alpha blockers reduce hypertension
-
Beta adrenergic receptros:
- -Beta 1: excitatory on cardiac muscles
- **beta blockers reduce heart rate
- -Beta 2: inhibitory on smooth muscles of repiratory tract, causes relaxation
-
Why should people not take Beta 2 blockers?
Cause airway to constrict
-
Which receptors are stimulated more by NE?
alpha
-
Epinephrine stimulates ________ alpha and beta receptors
both
-
Localized sympathetic activity from NE release at ______
- -variscosities
- **primarily affects alpha receptors near the active variscosities
-
Generalize sympathetic activity and release of _______ by adrenal medulla affect alpha AND beta receptors through out the body
-epinephrine
-
Operates without ___________ control via reflex centers in autonomic ganglia, spinal cord, and brainstem
-conscious
-
Reflex centers are controlled by the _________-
hypothalamus
-
What is autonomic tone?
- Basis for homeostasis
- -background level of activity
-
Activation of sympathetic and/or parasympathetic input can increase or decrease ___________
activity
-
Visceral reflexes:
- -Afferent input from sensory receptor/neuron
- -Processing center with one or more interneurons
- -Efferent pathway to effectors
-
Reflex processing centers:
- -Short reflexes (occur in autonomic ganglia - bypasses CNS)
- -Long reflexes (occur in CNS - hypothalamus or other center in brainstem) **Consciously aware but not conscious control
-
Short reflexes:
- -Bypass the CNS entirely
- -Involve sensory neurons and interneurons with cell bodies located in the autonomic ganglia, control ganglionic motor neurons
- -Typically control very simple motor response with localized effects whereas long reflexes coordinate activity of an entire organ
- **faster
-
Short reflexes in Enteric system:
- -Extensive networks of intramural ganglia and nerve networks in walls of digestive tract
- -influenced by sympathetic and parasympathetic input but many complex visceral relexes are initiated and coordinated locally without instructions from CNS
- *muscle contraction pushes everything through GI tract
- **smell, taste, eating food sets off reflexes to digest it
-
Long reflexes are the autonomic equivalent of ________ reflexes in somatic system
-polysynaptic
-
Long reflexes sensory input:
- -Visceral sensory neurons such as chemoreceptros, baroreceptors, etc. (Anything that detects change in chemicals in body - chemoreceptros)
- -General senses such as pain, touch, temperature, etc.
- -Special senses (smell, taste, vision, etc.)
-
Long reflexes processing steps involve ______ with in CNS
interneurons
-
Simple reflexes in SC provide relatively _____ and stereotypic responses to stimuli
rapid
-
Processing centers in the medulla and pons provide more __________ sympathetic and parasympathetic reflexes
complex
-
Autonomic Parasympathetic reflexes:
Typically affect individual organs/systems reflecting the relatively __________, restircted pattern of parasympathetic innervation
-
Parasympathetic reflexes include:
- -Defecation reflex
- -Urination reflex
- -Direct light and consensual light reflex
- -Swallowing reflex
- -Coughing reflex
- -Baroreceptor blood pressure reflex
- -Sexual arousal
-
Some Sympathetic autonomic reflexes affect individual organs such as:
- -Cardioacceleratory reflex
- -Vasomotor reflex
- -Pupil dilation reflex
- -Ejaculation of semen (can't occure without sympathetic stimulation)
-
Sympathetic division typically activated as a _______
whole
-
Release of NE and E as hormones produces widespread long lasting ________ effects
peripheral
-
Biofeedback:
-link between limbic and autonomic system
-
The hypothalamus:
- -Controls autonomic function
- -regulates body temp (thermostat)
- -coordinates circadian cycles of activity
- -produces emotions and behavorial drives
- -coordination of voluntary, emotional, and autonomic functions
- -coordinates activities of the endocrine and nervous systems
- -secretes regulatory hormones
-
Autonomic NS conrol and endocrine system controlled by:
-Hypothalamus
-
Sensory information comes into ____ from the sensory receptors via peripheral nerves
CNS
-
Afferent sensory pathways synapse onto sensory processing interneurons in _____ horn of SC or cranial nerve nuclei in brainstem
posterior
-
Only small percentage of sensory input reaches _______ awareness
conscious
-
Afferent sensory response occurs only if ______ exist that are sensitive to stimuli
receptors
-
Sensory receptros are specialized cell or ____ _______ that respond to specific stimuli, which are:
- cell responses,
- -dendrite of sensory neuron
- -specialized cell that synapses onto dendrite of sensory neuron
-
Receptor specificity:
-each receptor respond only to certain types of stimuli
-
Receptive field:
-area monitored by a singel sensory receptor
-
The longer the receptive field, the _____ precise the localization of the stimulus
-less
-
Sensory receptors translate ______ into bioelectrical activity of the nervous system
-stimuli
-
Sensory receptors transduction:
- -Stimulus changes membrane ion permeability producing the receptor potential (graded potential)
- -Receptor potential controls depolarization at AP initiation site in sensory neuron dendrite
- -AP frequency provides the CNS information on stimulus intensity
-
Sensation:
-information arriving from a stimulus
-
Perception:
-Conscious awareness of a sensation
-
Labeled line:
- -identifies type (modality) of stimulus and body location of receptor.
- **pathway dermatomes take from spinal cord
-
Sensory coding:
-Pattern of AP's arriving convey information on strength (frequency), duration, and variation of the stimulus
-
Adaptation:
-Reduction in sensitivity in the presense of a constant stimulus due to changes in receptor response or central processing
-
Tonic receptors:
-Always active - rate of AP changes with changes in level of stimulation
-
Phasic receptors:
- -Produce AP only in response to changes in level of stimulation
- -Fast-adapting receptors
-
Peripheral Adaptation:
- -Reduces amount of information that reaches the CNS
- **phasic receptors, body adapts to temp changes
-
Central adaptation:
- -Inhibition along a sensory pathway
- -Resrtricts amount of information that reaches the cortex and conscious awareness
- **adapting to strange smells unless it's normal
-
Reticular Activating system:
- -Reduces or increases awareness of arriving sensations
- **keep you alert or awake
-
Gereral pain receptor:
- nociceptors
- -Present in all spinal nerves
- -Present in CN V and CN X
- **generally free nerve endings
-
General temperature receptors:
- thermoreceptors
- -Present in all spinal nerves
- -Present in CN V and CN X
-
General senses for physical distortion:
- mechanoreceptors
- -Present in all spinal nerves
- -Present in CN V and CN X
- **pressure, stretching
-
General senses for chemical detection:
- -chemoreceptors
- -Present in all spinal nerves
- -Present in CN V and CN X
-
Nociceptors:
- -Free nerve endings: sensory neuron dendrites sensitive to various stimuli
- *extremes of temperature (where it causes pain)
- *mechanical damage (where it causes pain)
- *chemicals released by damaged cells (converted to prostaglandins)
- -abundant in suprficial skin, joint capsules, bone periosteum, blood vessel walls
- -few in deep tissues and visceral organs
- -Large receptive fields --> poor localization
-
Fast pain: "prickling pain"
- -carried by myelinated type A fibers (need immediate response)
- -trigger somatic muscle reflexes
- -relayed to cortex for conscious awareness
- -can be localized to within a few inches
-
Slow pain: burning, aching pain
- -carried by unmyelinated type C fibers
- -can be localized only to large body area
-
Nociceptors are _____ receptors
tonic
-
Central adaptation via inhibition in pain processing pathways:
- -excitatory neurotransmitters of pain pathway: Glutamate and Substance P
- -Inhibitory neurotransmitters: Endorphins and other "natural opiates" (make you realize you're not hurt until later)
-
Anesthetics block _______ sensations
all
-
What do local anesthetics do?
-They block AP propagation
-
What do general anesthetics do?
-They suppress consciousness
-
Analgesics (over the counter meds) _______ pain stimulus
inhibit
-
OTC meds (analgesics) inhibit ____________ synthesis, by blocking COX enzymes
prostaglandin
-
What blocks the COX enzyme?
OTC or analgesics
-
Non-steroidal anti-inflammatory drugs (NSAID's) block __________ and ____________
COX 1, and COX 2 enzymes
-
COX 2 inhibitors are _______ inhibitors
selective
-
____________ are analgesics that reduce transmission of information about pain in CNS
Opiates - agonists of endorphins
-
___________ are important to the transmission of pain
prostaglandins
-
_____________ are free nerve endings sensitive to change in temperature
Thermoreceptors
-
Thermoreceptors have more ________ sensitive receptors than warm sensitive receptors
cold
-
Where are thermoreceptors abundant?
- -dermis
- -skeletal muscle
- -liver
- -hypothalamus
-
Thermoreceptors have ____________ receptive fields
- large
- -less specific than pain
-
Thermoreceptors are _______ adapting receptors, or considered phasic
- rapidly
- -fast rate of acclimation to a temp that isn't painful
-
Warm receptors:
- -sensitive to temps above 77F
- -unresponsive to temps above 113F
-
Cold receptors:
-sensitive to temp between 50F and 68F
-
Pain receptors:
- -respond to temp below 10C
- -respond to temp above 45C
-
What temp are we most comfortable at?
between 70-77F
-
What are chemoreceptors sensitive to?
- -pH, CO2, and O2 levels of body fluids
- **including CSF (goes to brainstem and respiratory centers) and Arterial blood (goes to carotid and aortic bodies)
-
Chemoreceptors are _______ adapting receptors
rapidly
-
Chemoreceptors can ______ to new levels of O2 and CO2 after a duration of time
adapt
-
Chemoreceptors have a ________ control of respiration and cardiovascular system
reflex
-
Chemoreceptors have no pathways to ________ for conscious awareness
- cortex
- **O deficient people aren't always aware it's low
-
Mechanoreceptors are sensitive to _______ of the cell membrane of the dendrites (or pressure)
distortion
-
____________ gated ion channels open in response to stretching, compression, etc.
MEchanically
-
Baroreceptors:
-Pressure in blood vessels and hollow organs
-
Proprioceptors:
- -Position of joints muscles
- **in skeletal muscles and joints. Keep you upright. Abnormal stretching initiates reflex
-
Tactile receptors:
-touch, pressure, vibration
-
Sensory coding:
-pattern of AP's arriving convey info on strength, duration, and variation of the stimulus
-
Labeled line:
- -identifies type (motality) of stimulus and the body location of receptor (direct line from sensory cortex)
- **projects to brain processing centers that are organize somatotopically
- **most sensory info crosses over to contralateral areas of brain
-
More intense stimulus=more _________
frequency
-
Somatotopically organized=_________ representation of body regions
orderly
-
Amount of space in cortex and pathways devoted to a particular body region is proportional to the number of _____ ________ it contains, NOT to the body region's absolute size.
sensory receptor
-
What are unipolar neurons primary role?
-senses
-
Chemoreceptors have _______________ and receptor areas that have ______ gated ion channels
exteroceptors, chemically
-
Exteroceptors:
-respond to chemical stimuli from external environment
-
Olfaction and gustation receptors __________ rapidly and are continuously replaced with new cells
deteriorate
-
Olfaction= sense of _______
smell
-
Olfactory epithelium is located in superior portion of _______ cavity, and is composed of:
- -nasal
- *olfactory receptors
- *a lot of basal stem cells (constantly replaced)
- *supporting cells, glands, blood vessels, etc.
-
Olfactory epithelium surface is coated with mucus secretions from ______ glands, and what's the purpose of the mucus?
- -olfactory
- *to be detectable as a smell, chemical must be volatile (dissolved to gas form) and soluble in mucus
- *mucus cleans olfactory epithelium, removing chemicals
-
Olfactory receptors (cilia) are the ________ of bipolar neurons
dendrites
-
Cilia is a large area of membrane on which _________ gated channels are located
chemically
-
Humans have approximately 50 different types of __________ neurons
olfactory
-
Each neuron type is sensitive to only _____ chemical
one
-
Olfactory discrimination:
- -Humans can detect, discriminate between, approx. 2000-4000 different chemicals
- -CNS interprets between different SMELLS on the basis of the overall pattern of activity in the 50 different neuron types.
- ***one smell can activate multiple pathways/neurons
-
Olfactory receptors are very _____
- sensitive
- -Only a few molecules needed to open enough gates to reach AP threshold in some olfactory neurons
-
Which is more sensitive, gustation or olfaction?
olfaction (smell)
-
Olfactory 1st Order Neuron:
- -Receptor cell in olfactory epithelium:axon extend into CNS as cranial nerve I
- **Approximately 20 small bundles of axons (nerves) go through the cribriform plate--instead of one singel peripheral nerve
-
Olfactory: 2nd Order Neuron:
- -located in olfactory bulb
- **Much processing, including central adaptation (adjusting to a scent)
- **2nd order axons from olfactory tract that diverges to multiple sites
-
Olfactory: 3rd Order Neuron:
- -at various locations (a lot of splitting of the 3rd order neuron)
- **Olfactory cortex-medial surface of temporal lobe
- **Hypothalamus
- **Limbic system
-
Gustatory discrimination:
- -Humans can detect 4 to 6 "primary tastes"
- -CNS interprets different tastes on the basis of the overall pattern of activity in the 4 to 6 different recetor types
-
What are the 6 "primary tastes"
-sweet, salty, sour, umami, water, bitter
-
To be detectable as a taste, _______ must be dissolved
chemical
-
Mulitple gustatory receptors can be activated, but they are ______ sensitive than olfactory receptors
less
-
Taste buds:
- -Contain gustatory receptor cells and basal stem cells (constantly replacing receptor cells)
- -Recessed into surface of surrounding epithelium of lingual papillae
-
Gustatory receptor cells:
-4 to 6 different types of gustatory receptor cells, each sensitive to only one TYPE of chemical
-
Most taste buds have ____ 4-6 types of receptor cells
-all, can activated different combinations
-
What 2 senses are gustatory receptors less sensitive too?
sweet and salty
-
What are gustatory senses most sensitive to?
Bitter
-
Gustatory receptors are 1000 times more sensitive to _____ than sweet and salty
- sour (acids)
- -because more dangerous
-
Receptor cell in taste buds: ______ gated ion channels open, producing receptor potential
chemically
-
Gustatory: 1st Order Neuron
- -Dendrites receive synapse from receptor cell
- -Amount of neurotransmitter released by receptor cell determines AP frequency in 1st order neuron
- -Axon extends into CNS in cranial nerves
-
Which cranial nerves affect tongue:
- -CN VII (Facial): anterior 2/3 of tongue
- -CN IX (Glossopharyngeal): posterior 1/3
-
Level of stimulation of olfactory receptors has major role in ____ perception
taste
-
Aging reduces olfactory and gustatory sensitivity, because:
- -Number of receptors decline with age as fewer new cells are produced (becomes dull)
- -Receptor sensitivity declines
-
Bony labyrinth of inner ear:
- -surrounds and protects membranous labyrinth
- -Contains PERILYMPH (outermost fluid)
-
Membranous labyrinth of inner ear:
-Contains ENDOLYMPH (inside fluid)
-
What are the three areas the inner ear labyrinths are divided into:
- -Vestibule, with utricle and saccule (middle)
- -Semicircular canals, with semicircular ducts
- -Cochlea, with cochlear ducts
-
Hair cell=______ cell
receptor
-
Specialized cells termed hair cells are ______ receptors
mechano
-
Hair cells respond to ______ distortion of their cilia
physical
-
Amount of neurotransmitter released by hair cells controls AP frequency in _____ order neurons
1st
-
The sensory organs for hearing and equilibrium are located in the ____ _____
inner ear
-
Cranial nerve VIII (Vestibulocochlear): contains _____ order neurons that conduct AP's into CNS
1st
-
Semicircular ducts are responsible for ________ _______
rotational movements
-
Semicircular ducts: (location)
-in cristae: small patch of hair cells in ampullary region at one end of each of the 3 ducts
-
Utricle and Saccule:(location)
-In maculae: small patch of hair cells-one inside utricle, one inside saccule
-
Cochlear duct is responsible for _____
hearing
-
Cochlear duct: (location)
-In ORgan of Corti on Basilar membrane-long strip of hair cells extending the length of the coiled duct
-
Cupula:
-floating gelatinous mass in w hich "hairs" are embedded
-
Semicircular ducts are only activated during ______
movement
-
Utricle and sacculae are ________ active
always
-
Otolith:
-"hairs" embedded in gelatinous mass containing calcium carbonate crystal (part of utricle and sacculae)
-
Hair cells synapse onto 1st order sensory neurons, which enter CNS as _________ branch of CN VIII
vestibular
-
_____ order neuron located in vestibular nuclei of the brainstem
2nd
-
2nd order neurons in the vestibular neural pathway of the inner ear are responsible for:
- -integrating input from left and right inner ears
- -send info to the somato-sensory ears
- -send info to the cerebellum (for coordination)
- -send info to motor nuclei in BS and SC for reflex control of eye, head, and neck
-
Motion sickness:
- -sensory info from eyes and vestibules don't match up (a disconnect)
- -can have adaptations to sensory info or hypersensitivity - depends on how well you handle the disconnect
-
Nystagmus:
-Condition when eyes jerk when following a light: indicates brainstem damage
-
External and middle ear assist in getting stimulus (sound waves) to receptors in the _____ of the inner ear
cochlea
-
External ear (pinna and EAM) collects and ____ sound waves toward middle ear
directs
-
Middle ear (tympanic membrane and auditory ossicles) ______ and amplifies vibrations from tympanic membrane to onner ear
conducts
-
What is the cochlea filled with?
-perilymph and endolymph
-
Sound waves enter at the _____ window
oval
-
Sound waves exit at the ______ window
round
-
What is the pathway of sound waves:
- 1. sound waves arriving at tympanic membrane cause it to vibrate (causing aussicles to move)
- 2. Auditory ossicles conduct and amplify the vibration onto the oval window of the inner ear
- -Tensor tympani and stapedius MUSCLES contract to reduce the amount of movement when lound sound arrives (hol din place to keep from causing damage to the oval window)
- 3. In/out movement at the oval window creates pressure wave in the PERILYMPH of the cochlea
- 4. Pressure waves vibrate the basilar membrane area of the cochlear duct
- 5. Hair cells of the Organ of Corti are pushed against the tectorial membrane
-
Sound frequency depends on where _____ will cross the membrane
waves
-
Basilar membrane _______ varies along length of cochlear duct
flexibility
-
Highest frequency sounds vibrate areas _______ to oval window on Basilar membrane
closest
-
Lowest frequency sounds vibrate areas ________ from oval window on Basilar membrane
furthest
-
Higher intensity (louder) sounds cause larger ________ and stimulate more hair cells (intensity is measured in decibles)
vibration
-
Hair cells synapse onto ____ order sensory neurons, which enter CNS as cochlear branch of CN VIII
1st
-
_____ order neurons located in cochlear nuclei of the brainstem
2nd
-
2nd order neurons decussate and ascend to _____ order neurons in inferior colliculi of mesencephalon
3rd
-
Inferior colliculi coordinates ______ movement of head and neck to sounds
reflex
-
3rd order axons ascend to the _______, where there is conscious awareness and interpretation of sound
thalamus
-
Primary auditory cortex: (location)
superior surface of the temporal lobe
-
Auditory association cortex: (location)
- in surrounding areas of temporal lobe
- -left hemisphere interprets language
-
Which special sense is the most complicated?
vision
-
Eye:
-Sensory organ that collects and focuses light onto the photoreceptors (cones and rods)
-
Cornea and lens focus light rays onto ______, located on the inner surface of eye ball
retina
-
Light passes through layers of retinal neurons to reach ____________
photoreceptors
-
The outer pigmented portion of the retina does what?
- -Absorbs excess light
- -Transports nutrients to neural part
-
The inner neural part of the retina does what?
- -Has photoreceptors: rods and cones
- -1st order neurons: bipolar cells, axons
- -2nd order neurons: ganglion cells, axons form the optic nerve and tract
- -Embryologic origin:outgrowth from brain
-
Eyes are a direct _____ of the brain
outgrowth (meaning they are attached)
-
Cones of the retina:
- -provide color vision
- -require more light to be activated than rods
- -located in macula lutea portion of retina
- -In highest concentration in FOVEA portion of macula
-
Rods of the retina:
- -DO NOT DISTINGUISH COLORS
- -Highly sensitive to light, allow fro vision in DIM light conditions
- -found in retinal areas peripheral to macula
-
You switch from color (cones) to black and white (rods) at _____
dusk/night
-
Rods and cones convert _____ signals into electrical signals
light
-
Current flowing through gated ion channels changes membrane potential, controls ______ of neurotransmitter released onto 1st order neurons
amount
-
Gated ion channels in the eye open when its _____
dark
-
Light causes _____ channels to close so cell hyperpolarizes, which allows us to see images
sodium
-
Gated ion channels (mechanoreceptors and chemoreceptors) are indirectly controlled by _________
light
-
Each photopigment has _______ molecule, which changes shape
retinal
-
Light absorption activates enzyme pathway that controls ______ messenger (cGMP) levels that open gated channels
-
Light is absorbed by retinal molecule embedded in an _______ protein molecule (cones)
opsin
-
Retinal is synthesized from ________
Vitamin A
-
Opsins differ in which light frequencies can reach the ______ molecule
retinal
-
Vitamin A and ______ are constantly recycled in the eye, which is why it takes months to have signs of a deficiency
retinal
-
-
Rods respond to a ______ range of light wavelengths
- wide
- -responds to all the different wavelengths of the different colors
-
What are the 3 opsins?
Red, blue, and green sensitive cones
-
Cones respond to specific, _______ ranges of wavelengths, ranges overlap
narrower
-
The color white is perceived when all cones are _______ stimulated
equally
-
The color yellow is perceived when ______ cones are stimulated strongly, ________ cones are stimulated moderately, and ______ cones are not stimulated
green, red, blue
-
Colorblindness:
- -the inablity to detect certain colors due to lack of one or more color opsins
- -Inherited genetic trait: genes for red and green opsins are located on X chromosome
- -there are varying degrees of blindness, depends on colors
-
About ______ percent of cones are red cones
70
-
Labeled lines of visual pathway:
- -Each ganglion vell receives input from a specific receptive field of the retina, a group or photoreceptors
- -Image of retina surface is mapped onto visual cortex
- -Receptive fields are VERY SMALL IN FOVEA AREA OF RETINA (making it the SHARPEST vision)
- *highest visual acuity
- *large area on visual cortex
-
Steps of the visual pathway:
- 1. Light into eye
- 2. Light to photoreceptors (cones and rods)
- 3. Photoreceptors to bipolar cells to ganglion cells
- 4. Axons of ganglion cells form the optic nerve and optic tract
- **synapse on superior colliculus for visual reflex pathways
- **synapse on 3rd order neurons in the thalamus for conscious processing pathway
-
Primary visual cortex and visual association are in the ______ lobe of the brain
occipital
-
Riht visual field projects to ______ visual cortex
left
-
Left half of BOTH retinas view ______ visual field
right
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