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The SensesLaboratory

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The Variety of Senses

Mechanoreceptors – proprioceptors, touch, pressure, hearing, balance, pressure, vibration, movement

Chemoreceptors – taste, smell, visceral senses (O2, CO2, pH, etc.)

Thermoreceptors – hot and cold

Nociceptors – pain

Photoreceptors – vision

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The Special Senses

Based on the complexity of the receptors:

Taste

Smell

Vision

Hearing and balance

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Taste

Taste bud

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Circumvallate papillae

Taste cells

microvilli

Basal cellsFigure 16.1

Taste buds – groups of taste cells located on papillae of tongue as well as hard palate and epiglottis.

• circumvallate papillae – large, round, back of tongue.•filiform papillae – no taste buds, near tip, touch receptors.

•fungiform papillae – most abundant, over most of tongue.

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Fungiform Papillae on the Tongue

Taste budsStratified squamous epithelium

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Lateral View of the Eye

Figure 16.5

Levator palpebrae sup.

Sup. Rectus

Lat. Rectus

Inf. Rectus

Orbicularis oculi

Ocular conjunctiva Conjuctival sac Palpebral conjunctiva

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Anterior View of Eye

Figure 16.5

Lacrimal gland

Lacrimal canal

Lacrimal sac

Nasolacrimal duct

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Extrinsic Muscles of the Eye

Sup. Oblique m.

Sup. Oblique tendon

Trochlea

Lat. Rectus m.

Med. Rectus m.

Inf. Oblique m.

Inf. Rectus m.Lat. Rectus m.

Sup. Rectus m.

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Anatomy of the Eye

Sclera

Cornea

Anterior segment (contains aqueous

humor)Canal of Schlemm

Figure 16. 7

Vitreous body

Choroid coatRetina

Ciliary body

Suspensory lig.

Iris

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Sagittal Section

cornea

iris

anterior chamber

lens

posterior chamber

ciliary body

ora serrata

retina

choroid

sclera

optic diskSuspensory ligament

Posterior segment (vitreous body)

Anterior segment

muscle insertion

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Dissection of the Eye: The Optic Nerve

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Sheep Eye Cornea

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Sheep Eye Vitreous Humor

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Sheep Eye: Vitreous Humor and Lens

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Sheep Eye: Choroid Coat and Retina

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Sheep Eye: Ciliary Disk and Iris

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The Tapetum Lucidum

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Cadaver Eye Dissection

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The Ear

Auricle

External auditory canal

External ear

Middle ear Inner ear

Figure 16.24

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Middle and Inner EarOssicles: stapes incus malleous

Int. jugular v. Eustachian canal

Round window

Semicircular canals

Cochlea

Vestibule

Vestibular n. cochlear n.

of VIII

Tympanic membrane

Oval window

Figure 16.24

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Lab ProtocolI. The Eye: Exercise 24

A. Materials:

1. micro slides

2. Cadaver dissections: excised and in situ eye dissections

2. sheep eyes, one per 3-4 students

3. eye models, vision chart

` B. Procedures:

1. Identify indicated parts in models and specimens and relate structures to their functions.

2. Sheep eye dissection – relate to human eye.

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II. The Ear: Exercise 25

A. Materials:

1. cadaver dissection

2. ear models, tuning forks

B. Procedures:

1. Identify indicated parts in models and specimens and relate structures to their functions.

2. Perform selected tests and experiments in lab manual.