Download General sensation

General sensation
•
Composed of sensory receptors throughout the body.
–
General senses
•
–
Special senses
•
•
Exteroceptors
Interoceptors
Propioceptors (sketetal muscle). Conscious.
General structure (histology, activity 1)
–
Modified dendrites.
•
•
•
•
•
•
•
•
•
Vision, hearing, equilibrium, olfaction, taste.
Relative to the source of the stimuli.
–
–
–
•
Touch, pressure, pain, heat, cold, stretch, vibration.
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.
2.
3.
4.
Vision
Olfaction
Taste
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
The eye and associated accessory structures
Site where
conjunctiva
merges with
cornea
Palpebral
fissure
Eyebrow
Eyelid
Eyelashes
Pupil
Lacrimal
caruncle
Lateral
commissure
(canthus)
Medial
commissure
(canthus)
Iris
Sclera
(covered by
conjunctiva)
Eyelid
(a)
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
The lacrimal apparatus
Lacrimal
gland
Lacrimal sac
Excretory ducts
of lacrimal gland
Lacrimal punctum
Lacrimal canaliculus
Nasolacrimal duct
Inferior meatus
of nasal cavity
Nostril
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
The eye and associated accessory structures
Levator palpebrae
superioris muscle
Orbicularis
oculi muscle
Eyebrow
Tarsal plate
Palpebral
conjunctiva
Tarsal
glands
Cornea
Palpebral
fissure
Eyelashes
Bulbar
conjunctiva
Conjunctival
sac
Orbicularis
oculi muscle
(b)
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
Extrinsic eye muscles
Trochlea
Superior oblique muscle
Superior oblique tendon
Superior rectus muscle
Axis at
center
of eye
Inferior
rectus muscle
Medial
rectus muscle
Lateral
rectus muscle
Lateral rectus muscle
Conjunctiva
Optic
nerve
(a)
Inferior Inferior
rectus oblique
muscle muscle
Name
Lateral rectus
Medial rectus
Superior rectus
Inferior rectus
Inferior oblique
Superior oblique
Annular ring
(b)
Controlling cranial
nerve
Moves eye laterally
VI (abducens)
Moves eye medially
III (oculomotor)
Elevates eye and turns it medially III (oculomotor)
Depresses eye and turns it medially III (oculomotor)
Elevates eye and turns it laterally III (oculomotor)
Depresses eye and turns it laterally IV (trochlear)
Action
(c)
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
Internal structure of the eye
•
Composed of 3 layers or tunics
–
External
•
–
Cornea (transparent) and Sclera (white).
Middle
•
Anterior
–
–
–
–
•
Posterior
–
–
Retina: sensory region
Additional internal structures
–
–
–
–
–
•
Choroid: dark pigment.
Inner
•
•
Iris: radial smooth muscle (III ocoulomotor)
Uvea: vasculariazed.
Cilliar body(muscles) : control the curvature of the lens (cristaline).
Cilliary processes: secrete aqueous humor.
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)
Internal structure of the eye (sagittal section)
Ora serrata
Sclera
Ciliary body
Choroid
Ciliary zonule
(suspensory
ligament)
Retina
Macula lutea
Cornea
Iris
Pupil
Anterior
pole
Fovea centralis
Posterior pole
Optic nerve
Anterior
segment
(cavity)
Lens
Scleral venous sinus
(Canal of Schlemm)
Posterior segment (cavity)
(contains vitreous humor)
Central artery
and vein of the retina
Optic disc
(blind spot)
(a)
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
Circulation of aqueous humor
Cornea
Lens
Iris
Lens
epithelium
Cornea
Posterior
segment
containing
vitreous
humor
Lens
Corneal epithelium
ANTERIOR
Corneal endothelium
Aqueous humor
Anterior chamber
Anterior
segment
Ciliary zonule
(suspensory
ligament)
Posterior chamber
Scleral venous
sinus
Ciliary
processes
Limbus (cornealscleral junction)
Ciliary body
Ciliary
muscle
Anterior ciliary vein
Bulbar
conjunctiva
Sclera
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
Focusing for distant and close vision
Sympathetic +
Nearly parallel rays
from distant object
Lens
Ciliary zonule
Inverted
image
Ciliary muscle
Lens
(a) Lens is flattened for distant vision
Ciliary zonule
(suspensory ligaments)
Parasympathetic +
Divergent rays
from close object
Ciliary muscle
Inverted
image
(c) Anterior segment viewed from behind
(b) Lens bulges for close vision
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
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
Photoreceptors of the retina
Process of
bipolar cell
Synaptic
terminals
Rod cell
body
Inner
fibers
Rod cell
body
Cone cell
body
Mitochondria
Outer segment Inner segment
Pigmented layer
Outer
fiber
Nuclei
Retinal
(b)
Opsin
Connecting
cilia
Apical microvillus
Discs being
phagocytized
Discs containing
visual pigments
Melanin
granules
Pigment cell
nucleus
Basal lamina
(border with choroid)
(a)
Human Anatomy and Physiology, 7e
by 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
Fixation
point
Right eye
Left eye
Optic nerve
Suprachiasmatic
nucleus
Pretectal
nucleus
Optic chiasma
Optic tract
Lateral
geniculate
body
Superior
colliculus
(sectioned)
Uncrossed
(ipsilateral) fiber
Crossed
(contralateral) fiber
Optic
radiation
Lateral geniculate
body of thalamus
Superior colliculus
(a)
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Occipital lobe (visual cortex)
Corpus callosum
(b)
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
2. Olfaction
• Sensory structure:
– Olfactory epithelium. Chemoreceptor.
• Olfactory receptor cell: bipolar neuron (I)
• Support cells: pseudo stratified ciliated epithelium.
• Basal cells.
• Activity 1
Olfactory receptors
Olfactory
epithelium
Frontal lobe
of cerebrum
Olfactory tract
Olfactory
bulb
Mitral cell
Olfactory
tract
Glomeruli
Nasal
conchae
Route of
inhaled air
Cribriform plate
of ethmoid bone
Olfactory
epithelium
Filaments of
olfactory nerve
Lamina propria
connective tissue
Axon
Basal cell
Olfactory receptor
cell
Supporting cell
Mucus
Dendrite
Olfactory cilia
Olfactory
gland
Route of inhaled
air containing odor
molecules
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
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
Location and structure of taste buds on the tongue
Taste fibers
of cranial
nerve
Gustatory
hair
Epiglottis
Taste
pore
Palatine tonsil
Lingual tonsil
Basal cell
Circumvallate papilla
Foliate
papillae
Stratified
squamous
epithelium
of tongue
Gustatory (taste) cells
Taste
pore
Connective Gustatory
tissue
receptor
cells
(c)
Connective
tissue
(a)
Fungiform
papillae
(b)
Taste bud
Basal
cells
(d)
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
The gustatory pathway
Gustatory
cortex
(in insula)
Thalamic
nucleus
(ventral
posterior
Pons
medial
nucleus)
Solitary nucleus
in medulla oblongata
Facial
nerve (VII)
Glossopharyngeal
nerve (IX)
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Vagus
(nerve X)
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
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
Structure of the ear
External
(outer) ear
Middle
ear
Internal
(inner) ear
(labryinth)
Auricle
(pinna)
Helix
Lobule
External
acoustic
meatus
Tympanic membrane
Pharyngotympanic
(auditory) tube
(a)
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
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.
Structure of the middle ear
Entrance to mastoid antrum
in the epitympanic recess
Auditory
ossicles
Malleus
(hammer)
Incus
(anvil)
Stapes
(stirrup)
Semicircular
canals
Vestibule
Vestibular
nerve
External
acoustic
meatus
Cochlear
nerve
Cochlea
Tympanic
membrane
Oval window
(deep to stapes)
(b)
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Internal
jugular vein
Pharyngotympanic
(auditory) tube
Round window
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
The three auditory ossicles in the right middle ear
Malleus
Incus Epitympanic recess
Superior
Anterior
Pharyngotym- Tensor
panic tube
tympani
muscle
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Tympanic
Stapes
membrane
(medial view)
Stapedius
muscle
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
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).
Membranous labyrinth of the internal ear
Temporal
bone
Facial nerve
Semicircular ducts in
semicircular canals:
Vestibular nerve
• Anterior
Superior vestibular ganglion
• Posterior
Inferior vestibular ganglion
• Lateral
Cochlear nerve
Cristae ampullares
in the ampullae
Maculae
Spiral organ (of Corti)
Utricle in vestibule
Cochlear duct in cochlea
Saccule in vestibule
Stapes in
oval window
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Round window
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
Anatomy of the cochlea
Modiolus
Oval
window
(a)
Round window
Helicotrema
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Cochlear nerve,
division of the
vestibulocochlear
nerve (VIII)
Spiral ganglion
Osseous
spiral lamina
Vestibular
membrane
Cochlear duct
(scala media)
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
Anatomy of the cochlea
Tectorial
membrane
Cochlear duct
(scala media)
Vestibular
membrane
Scala
vestibuli
Stria
vascularis
Spiral
organ
(of Corti)
Basilar
membrane
Scala
tympani
Spiral
ganglion
Osseous
spiral
lamina
(b)
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
Anatomy of the cochlea
Tectorial
membrane
Inner hair cell
Hairs (stereocilia)
Afferent nerve
fibers
Outer hair cells
Supporting
cells
(c)
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Fibers of
cochlear
nerve
Basilar
membrane
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
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.
Sound: source and propagation
Area of
compressed
molecules
(a)
Air pressure
Wavelength
Area of
rarefaction
Crest
Trough
Time
(b)
Amplitude
(c)
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
Route of sound waves through the ear
External ear
Tympanic
membrane
Malleus, incus,
stapes
(ossicles)
Internal ear
Oval
window
Fluids in cochlear canals
Upper and middle
Lower
Pressure
Pinna
Air
External
acoustic
meatus
Middle ear
One
vibration
Amplitude
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Amplification
in middle ear
Spiral organ
(of Corti)
stimulated
Time
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
Resonance of the basilar membrane and activation of the cochlear hair cells
Stapes
Scala
Cochlear
vestibuli
nerve
Perilymph
Oval
window
Round
window
Scala
tympani
Basilar
membrane
Cochlear
duct
(a)
Base
Relative
lengths
of basilar
fibers
within
different
regions
of basilar
membrane
(b)
Hz
20,000
(High notes)
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Apex
Basilar
membrane
500 Hz
4000 Hz
Hz
1500
Hz
500
Hz
20
(Low notes) (c)
24,000 Hz
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
Simplified diagram of the auditory pathway to the auditory cortex of the brain
Medial
geniculate
body of
thalamus
Primary auditory
cortex in temporal lobe
Inferior colliculus
Lateral lemniscus
Superior olivary
nucleus (ponsmedulla junction)
Midbrain
Cochlear nuclei
Vibrations
Vibrations
Medulla
Vestibulocochlear
nerve
Spiral ganglion
of cochlear nerve
Bipolar cell
Spiral organ
(of Corti)
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
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.
Structure of a macula
Macula of
saccule
Macula of
utricle
Kinocilium
Stereocilia
Otoliths Otolithic
membrane
Hair bundle
Hair cells
Vestibular
nerve fibers
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Supporting
cells
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
The effect of gravitational pull on a macula receptor cell in the utricle
Otolithic
membrane
Kinocilium
Stereocilia
Depolarization
Hyperpolarization
Receptor
potential
(Hairs bent toward
kinocilium)
Nerve
impulses
generated in
vestibular fiber
Increased
impulse frequency
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Excitation
(Hairs bent away
from kinocilium)
Decreased
impulse frequency
Inhibition
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
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.
Location and sturcture of a crista ampullaris
Flow of
endolymph
Crista
ampullaris
(a)
Fibers of
vestibular nerve
Cupula
(b)
Turning motion
Cupula
Position
of cupula
during turn
(c)
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Increased firing
(d)
Ampulla
of left ear
Cupula at rest
Ampulla of
right ear
Position of cupula
during turn
Fluid motion in
ducts
Horizontal ducts
Decreased firing
Afferent fibers of vestibular nerve
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.
Pathways of the balance and orientation system
Vestibular
receptors
Visual
receptors
Somatic
receptors
Vestibular
nuclear
complex
Reticular
nuclei
Input
Cerebellum
Central nervous
system processing
Oculomotor control
(cranial nerve nuclei
III, IV, VI)
(eye movements)
Spinal motor control
(cranial nerve nuclei XI
and vestibulospinal tracts)
(neck movements)
Output
Human Anatomy and Physiology, 7e
by Elaine Marieb & Katja Hoehn
Copyright © 2007 Pearson Education, Inc.,
publishing as Benjamin Cummings.