VT 111 Lab 4 Special Senses

Sensory Receptors of the Skin

Pacinian and Meissner’s Corpuscles:

 

• Located in the skin

• Modified dendritic endings for detecting  touch

• Pacinian corpuscles are for deep pressure

• Meissner’s corpuscles are for touch or light pressure

Pig Skin

Eye Diagram

Outer Eye

Extraocular Muscles

Accommodation

• The process of focusing light on the retina for close-up and distant vision

  • Relaxation of ciliary muscle pose lens flat for long distance vision

  • Contraction of ciliary Muscle lens forms a ball close-up vision

Vestibulocochlear Apparatus

Uses the eighth cranial nerve (CN VIII) to send information about sound and head position/movement to the brain

Semicircular Canals

• Three semi circular canals in each ear that are part of the vestibular system.

• They sense rotary motion of the head.

• Maintain balance and stabilize vision.

Vestibule: Utricle & Saccule

• Utricle is for detection of linear acceleration or position in a horizontal plane

• Saccule Is for detection of linear acceleration or position in a vertical plane

Bony Ossicles

• Malleus: transmit sound wave vibrations across the middle ear; A.k.a., the hammer, is the outermost of the three ossicles and is attached to the tympanic membrane

• Incus: Transmit sound wave vibrations across the middle ear; a.k.a. anvil is the middle of the three ossicle

• Stapes: Transmit sound wave vibrations across the middle ear; a.k.a. the stirrup is attached to the membrane that covers the oval window of the cochlea. Innermost of the three ossicles

Tympanic Membrane

The eardrum. The paper, thin, connective tissue membrane that is tightly stretched across the opening of the external ear canal into the middle ear.

External Ear Canal

Channeling sound waves from the outer ear to the eardrum (tympanic membrane)

Eustachian Tube

The tube that connects the middle ear cavity with the pharynx. It allows equalization of the air pressure on the two sides of the tympanic membrane.

Pinna

The extremely visible part of the ear that collects sound waves and funnels them down into the external ear canal, the ear flap

Extrinsic ocular muscles

Cornea

Sclera

Iris

Optic Nerve

Pupil

Lens

Ciliary Body

Vitreous Humor

Retina

Choroid, Tapetum Luciudum & Optic Disc

Limbus

Ear: brief external & internal

Cochlea Up Close (unwound)

Inner Ear

Organ of Corti

Vestibular Anatomy

Semicircular Canals