General sensation Composed of sensory receptors throughout the body. –General senses Touch,...
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Transcript of General sensation Composed of sensory receptors throughout the body. –General senses Touch,...
General sensation• Composed of sensory receptors throughout the body.
– General senses• Touch, pressure, pain, heat, cold, stretch, vibration.
– Special senses • Vision, hearing, equilibrium, olfaction, taste.
• Relative to the source of the stimuli.– Exteroceptors– Interoceptors– Propioceptors (sketetal muscle). Conscious.
• General structure (histology, activity 1)– Modified dendrites.
• Free nerve endings• Merkel discs in epidermis• Hair follicle receptors• Meissner corpuscles: light touch• Ruffini corpuscles: deep pressure and stretching.• Pacinian corpuscles: pressure recptor.• Muscle spindles• Golgi tendon organs
• Receptor physiology– Act as signal transducers. Direct relationship between importance and number of clustering of the receptors;
punctuate distribution.
Special Senses
1. Vision
2. Olfaction
3. Taste
4. Hearing and equilibrium
1. Vision
• Organ: Eye ball• Accessory structures
– Lacrimal apparatus.• Lacrimal gland: secretes tears; solution of salts and lyzozyme.• Lacrimal canals• Nasolacrimal canal
– Eyelids (papebrae)– Medial and lateral canthus– Caruncle– Conjunctiva. Mucus membrane that lines inner surface of eyelids. Stratified
squamous and stratified cilindrical epithelium.– Eyelashes– Ciliary glands: lubricate eyeball– Tarsal glands: lubricate eyeball– 6 extrinsic eye muscles
• Activity 1
Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.
The eye and associated accessory structures
(a)
Eyelashes
Sclera(covered byconjunctiva)
Site whereconjunctivamerges withcornea
Lateralcommissure(canthus)
Iris
Medialcommissure(canthus)
Lacrimalcaruncle
Eyelid
Eyelid
Eyebrow
PupilPalpebralfissure
Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.
The lacrimal apparatus
Lacrimal sacLacrimalgland
Excretory ductsof lacrimal gland
Lacrimal punctum
Lacrimal canaliculus
Nasolacrimal duct
Inferior meatusof nasal cavity
Nostril
Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.
The eye and associated accessory structures
(b)
Levator palpebraesuperioris muscle
Orbicularisoculi muscleEyebrow
Tarsal plate
PalpebralconjunctivaTarsalglands
Cornea
Palpebralfissure
Eyelashes
Bulbarconjunctiva
Conjunctivalsac
Orbicularisoculi muscle
Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.
Extrinsic eye muscles
(a) (b)
(c)
Opticnerve
Inferiorrectusmuscle
Inferiorobliquemuscle
Superior oblique muscle
Annular ring
Trochlea
Superior oblique tendon
Superior rectus muscle
Lateral rectus muscle
Conjunctiva
Axis atcenterof eye
Medialrectus muscle
Inferiorrectus muscle
Lateralrectus muscle
Lateral rectusMedial rectusSuperior rectusInferior rectusInferior obliqueSuperior oblique
Name Action
Moves eye laterallyMoves eye mediallyElevates eye and turns it mediallyDepresses eye and turns it mediallyElevates eye and turns it laterallyDepresses eye and turns it laterally
VI (abducens)III (oculomotor)III (oculomotor)III (oculomotor)III (oculomotor)IV (trochlear)
Controlling cranialnerve
Internal structure of the eye• Composed of 3 layers or tunics
– External• Cornea (transparent) and Sclera (white).
– Middle• Anterior
– Iris: radial smooth muscle (III ocoulomotor)– Uvea: vasculariazed. – Cilliar body(muscles) : control the curvature of the lens (cristaline).– Cilliary processes: secrete aqueous humor.
• Posterior– Choroid: dark pigment.
– Inner• Retina: sensory region
• Additional internal structures – Humor vitreous– Macula lutea (yellow spot): high cone density– Fovea centralis: area of maximum (very high amount of cones) sight acuity.– Sclera venous sins( Schlemm canal)– Ciliary zonule
• Activity 2 (eye dissection next class)
Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.
Internal structure of the eye (sagittal section)
(a)
Ora serrata
Ciliary body
Ciliary zonule(suspensoryligament)
Cornea
Iris
Anteriorpole
Pupil
Anteriorsegment(cavity)
Lens
Scleral venous sinus(Canal of Schlemm)
Posterior segment (cavity) (contains vitreous humor)
Optic nerve
Posterior pole
Fovea centralis
Macula lutea
Retina
Choroid
Sclera
Central arteryand vein of the retina
Optic disc(blind spot)
Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.
Circulation of aqueous humor
Sclera
Bulbarconjunctiva
Anterior ciliary vein
Scleral venous sinus
Posterior chamber
Anterior chamberAnteriorsegment
Limbus (corneal-scleral junction)
Cornea
Cornea
Corneal epithelium
Corneal endothelium
Aqueous humor
Iris
Lens
Lens epithelium
Lens
Posterior segmentcontaining vitreoushumor
Ciliary zonule(suspensoryligament)
Ciliaryprocesses
Ciliarymuscle
Ciliary body
ANTERIOR
Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.
Focusing for distant and close vision
(a) Lens is flattened for distant vision
(b) Lens bulges for close vision
(c) Anterior segment viewed from behind
Lens
Invertedimage
Ciliary zonule
Ciliary muscle
Nearly parallel raysfrom distant object
Sympathetic +
Divergent raysfrom close object
Invertedimage
Parasympathetic +
Ciliary muscle
Lens
Ciliary zonule(suspensory ligaments)
Histology of the retina
• Sensory tunic– Outer pigmented epithelial layer
– Inner neural layer. • Photoreceptors: cones or rods.
• Bipolar neurons
• Ganglion
• Axons of ganglions
• Activity 3
Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.
Photoreceptors of the retina
Process ofbipolar cell
Outerfiber
Apical microvillus
Discs containingvisual pigments
Inn
er s
egm
ent
Melaningranules
Pigment cellnucleus
Innerfibers
Rod cellbody
Cone cellbody
SynapticterminalsRod cellbody
Nuclei
Mitochondria
Connectingcilia
Ou
ter
seg
men
t
Pig
men
ted
lay
er
Basal lamina(border with choroid)
Retinal
Opsin
Discs beingphagocytized
(a)
(b)Li
ght
Lig
ht
Lig
ht
Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.
Visual fields of the eyes and visual pathway to the brain, inferior view
(a) (b)
Pretectalnucleus
Right eye Left eye
Fixationpoint
Opticradiation
Superiorcolliculus(sectioned)
Lateralgeniculatebody
Optic tractOptic chiasma
Uncrossed (ipsilateral) fiberCrossed (contralateral) fiber
Optic nerve
Lateral geniculatebody of thalamus
Superior colliculusOccipital lobe (visual cortex) Corpus callosum
Supra-chiasmaticnucleus
2. Olfaction
• Sensory structure:– Olfactory epithelium. Chemoreceptor.
• Olfactory receptor cell: bipolar neuron (I)
• Support cells: pseudo stratified ciliated epithelium.
• Basal cells.
• Activity 1
Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.
Olfactory receptors
Mitral cell
Olfactorygland
Olfactorytract
Olfactoryepithelium
Filaments of olfactory nerve
Cribriform plateof ethmoid bone
Lamina propria connective tissue
Basal cell
Supporting cell
Dendrite
Olfactory cilia
Glomeruli
Axon
Olfactory receptorcell
Mucus
Route of inhaledair containing odormolecules
Frontal lobeof cerebrum
Nasalconchae
Route ofinhaled air
Olfactoryepithelium
Olfactory tractOlfactorybulb
Red: support cell
Blue:bipolar neuron
Green:basal cell
Green:Bowman’s gland cell
3. Taste
• Sensory structure– Taste bud. Chemoreceptor. Mechanoreceptor. Thermo
receptor. • Basic tastes: sweet, sour, salt, bitter.• Types (location in figure)
– Fungiform papillae (mushrooms)– Circunvallate papilla (globes)– Filiform papilla
• Cell types– Gustatory (taste) cells: bipolar neurons.– Support cells
• Activity 2
Fg: fungiform papillae
Fl: filliform papillae
Weather’s Fucntional Histology
Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.
(a)(b)
(c)
(d)
Fungiformpapillae
Taste bud
Circumvallate papilla
Epiglottis
Palatine tonsil
Foliatepapillae
Lingual tonsil Basal cell
Taste fibersof cranialnerve
Connective tissue
Gustatoryreceptorcells
Tastepore
Gustatoryhair
Stratifiedsquamousepitheliumof tongue
Gustatory (taste) cells Tastepore
Connective tissue
Basal cells
Location and structure of taste buds on the tongue
Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.
The gustatory pathway
Gustatorycortex(in insula)
Thalamicnucleus(ventralposteriormedialnucleus)
Pons
Solitary nucleusin medulla oblongata
Facialnerve (VII)
Glosso-pharyngealnerve (IX)
Vagus(nerve X)
4. Hearing and balance
• Organ: Ear (sensory receptor for hearing and equilibrium).– Outer ear. Hearing
• Auricle• External acoustic meatus• Tympanic membrane• Ceruminous glands
– Middle ear. Hearing• Tympanic cavity
– Osicles» Malleus (hammer)» Incus (anvil)» Staples (stirrup). Connects with the oval window.
• Pharingotimpanic tube. Pressure equalization of middle ear and environment.– Inner ear
• Bony and membranous labyrinth– Cochlea: hearing– Vestible: equilibrium– 3 perpendicular semicircular canals: equilibrium
Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.
Structure of the ear
(a)
External(outer) ear Middle
ear
Internal(inner) ear(labryinth)
Pharyngotympanic(auditory) tube
Externalacousticmeatus
Auricle(pinna)
Helix
Lobule
Tympanic membrane
Middle ear
• Middle ear. Hearing– Tympanic cavity
• Osicles– Malleus (hammer)
– Incus (anvil)
– Staples (stirrup). Connects with the oval window.
• Pharingotimpanic tube. Pressure equalization of middle ear and environment.
Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.
Structure of the middle ear
(b)
Pharyngotympanic(auditory) tube
Auditoryossicles
Entrance to mastoid antrum in the epitympanic recess
Tympanicmembrane
Semicircularcanals
Cochlea
Cochlearnerve
Vestibularnerve
Oval window(deep to stapes)
Round window
Incus(anvil)
Malleus(hammer)
Stapes(stirrup)
Internaljugular vein
Vestibule
Externalacousticmeatus
Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.
The three auditory ossicles in the right middle ear
Pharyngotym-panic tube
Tensortympanimuscle
Tympanicmembrane(medial view)
Stapes
Malleus
Superior
Anterior
Incus Epitympanic recess
Stapediusmuscle
Inner ear
• Inner ear– Bony labyrinth
• Contains perilymph; similar composition to CSF since it is connected to the arachnoid space.
– Membranous labyrinth• Suspended in perilymph, contains endolymph.• Divisions:
– Cochlea: organ of Corti, hearing VIII.– Vestible:
» utricle and sacule. Macula; vertcial acceleration (equilibrium).– 3 perpendicular semicircular canals
» Semicircular duct. Ampula; angular acceleration (equilibrium).
Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.
• Anterior
Semicircular ducts insemicircular canals:
• Posterior
• Lateral
Cristae ampullaresin the ampullae
Utricle in vestibule
Saccule in vestibule
Stapes inoval window
Temporalbone
Facial nerve
Vestibular nerve
Superior vestibular ganglion
Inferior vestibular ganglion
Cochlear nerve
Maculae
Spiral organ (of Corti)
Cochlear duct in cochlea
Round window
Membranous labyrinth of the internal ear
Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.
Anatomy of the cochlea
(a)
Ovalwindow
Round window
Helicotrema
ModiolusCochlear nerve,division of thevestibulocochlearnerve (VIII)
Cochlear duct(scala media)
Spiral ganglion
Osseousspiral lamina
Vestibularmembrane
Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.
Anatomy of the cochlea
(b)
Cochlear duct(scala media)
Tectorialmembrane
Vestibularmembrane
Scala vestibuli
Scala tympaniBasilar
membrane
Spiralorgan(of Corti)
Striavascularis
Spiralganglion
Osseousspirallamina
Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.
Anatomy of the cochlea
(c)
Tectorialmembrane
Inner hair cell
Outer hair cells
Hairs (stereocilia)Afferent nervefibers
Basilarmembrane
Fibers ofcochlearnerve
Supportingcells
Hearing physiology
• Sound waves travel from the outer ear (timpanic membrane) middle ear (Malleus,Incus, staples, oval window) inner ear (scala tympani)/scala vestibuli stimulates the stereocillia of the organ of corti VIII
• The round window serves as a pressure relief valve.
Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.
Sound: source and propagation
(a) (b)
(c)
Area ofcompressedmolecules
Crest
Trough
Time Amplitude
Area ofrarefaction
Wavelength
Air
pre
ssu
re
Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.
Route of sound waves through the ear
Fluids in cochlear canals
Upper and middle
Internal earExternal ear
PinnaExternalacousticmeatus
Air
Tympanicmembrane
Malleus, incus,stapes
(ossicles)
Ovalwindow Lower
Middle ear
Onevibration
TimeSpiral organ
(of Corti)stimulated
Amplificationin middle ear
Amplitude
Pre
ssu
re
Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.
Resonance of the basilar membrane and activation of the cochlear hair cells
(a)
(b) (c)
Stapes
Ovalwindow
Scalavestibuli
Cochlearduct
Scalatympani
Basilarmembrane
Roundwindow
Base
Hz20,000
(High notes)
Hz1500
Hz500
500 Hz
4000 Hz
24,000 HzHz20
(Low notes)
Apex
Perilymph
Cochlearnerve
Relativelengthsof basilarfiberswithindifferentregionsof basilarmembrane
Basilarmembrane
Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.
Simplified diagram of the auditory pathway to the auditory cortex of the brain
Medialgeniculatebody ofthalamus
Primary auditorycortex in temporal lobe
Inferior colliculus
Lateral lemniscus
Superior olivarynucleus (pons-medulla junction)
Spiral organ(of Corti)
Bipolar cell
Spiral ganglionof cochlear nerve
Vestibulocochlearnerve
Medulla
Midbrain
Cochlear nuclei
Vibrations
Vibrations
Equilibrium physiology
• Located in the vestibular apparatus– Vestible
• Utricle and saccule (sacs) within vesitble.– Receptor: Macculae (static equilibrium)
» Hair cells (stereocillia) are embedded in the otholitic membrane which contain CaCO3 (otoliths). Respond to vertical acceleration.
– Membranous semicircular ducts• Ampulla (located at the base of each perpendicular duct).
Mechism of dynamic equilibrium (angular acceleration).– Receptor: Crista ampullaris. Stereocilia covered by a
gelatinous cupula. Endolymph stimulates the recptor.
Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.
Structure of a macula
Macula ofutricle
Macula ofsaccule
Otoliths
Hair bundle
KinociliumStereocilia Otolithic
membrane
Vestibularnerve fibers
Hair cells
Supportingcells
Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.
The effect of gravitational pull on a macula receptor cell in the utricle
Otolithicmembrane
Kinocilium
Stereocilia
Receptorpotential
Nerveimpulsesgenerated investibular fiber
Depolarization
(Hairs bent towarkinocilium)
dHyperpolarization
(Hairs bent awayfrom kinocilium)
Increasedimpulse frequency
Excitation
Decreasedimpulse frequency
Inhibition
Macula within the utriculus (otolith chamber) (Bouins, H&E, Bar = 36.4 µm). 1. ciliated sensory cells; 2. sustenticular cells; 3. connective tissue; 4. cupula (gelatinous matrix); 5. globular sensory epithelium; 6. collagenous connective tissue; 7. otolith chamber; 8. cranium.
Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.
Location and sturcture of a crista ampullaris
(a)
(c) (d)
(b)
Cupula Cupula at rest
Position of cupuladuring turn
Turning motion
Fluid motion inducts
Afferent fibers of vestibular nerve
Increased firing Decreased firing
Position of cupuladuring turn
Ampulla of left ear
Ampulla ofright ear
Horizontal ducts
Flow ofendolymph
Cupula
Cristaampullaris
Fibers ofvestibular nerve
Human Anatomy and Physiology, 7eby Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,publishing as Benjamin Cummings.
Pathways of the balance and orientation system
Input
Central nervoussystem processing
Output
Oculomotor control(cranial nerve nucleiIII, IV, VI)(eye movements)
Spinal motor control(cranial nerve nuclei XIand vestibulospinal tracts)(neck movements)
Vestibularreceptors
Visualreceptors
CerebellumVestibularnuclearcomplex
Reticularnuclei
Somaticreceptors