The Special Senses: Olfaction
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Questions and Answers

What is the primary function of the palpebrae?

  • To protect the eye and distribute lubrication (correct)
  • To produce tear secretions for lubrication
  • To regulate light entering the eye
  • To provide structural support for the eyeball

    • What is the palpebral fissure?

  • The inner surface of the eyelid
  • The opening between the upper and lower eyelids (correct)
  • The outer surface of the eye
  • The area where the lacrimal gland is located

    • The lacrimal caruncle is responsible for:

  • Generating 'sand-like' deposits, and thick secretions (correct)
  • Draining excess tears from the eye
  • Producing antibacterial enzymes
  • Distributing tears across the eye surface

    • What is the function of the conjunctiva?

    <p>To cover the outer surface of the eye and inner surfaces of the eyelids (B)</p> Signup and view all the answers

    Which part of the eye is known as the 'tear gland'?

    <p>The lacrimal gland (A)</p> Signup and view all the answers

    Which of the following best describes the function of the lacrimal apparatus?

    <p>To produce, distribute, and drain tears (D)</p> Signup and view all the answers

    What is a key component of the tear secretions produced by the lacrimal gland?

    <p>Lysozyme, an antibacterial enzyme (D)</p> Signup and view all the answers

    Which is NOT a layer of the eye structure?

    <p>Muscular tunic (D)</p> Signup and view all the answers

    Which layer is the outermost layer of the eye?

    <p>Fibrous tunic (B)</p> Signup and view all the answers

    Viral conjunctivitis is an infection that affects what part of the eye?

    <p>Palpebral conjunctiva (D)</p> Signup and view all the answers

    Which layer of the olfactory organs contains olfactory receptors?

    <p>Olfactory epithelium (D)</p> Signup and view all the answers

    What is the role of olfactory glands in the sense of smell?

    <p>To coat the surfaces of olfactory organs. (A)</p> Signup and view all the answers

    Where does the first synapse occur in the olfactory pathway?

    <p>Olfactory bulb of the cerebrum (C)</p> Signup and view all the answers

    Which of the following best describes how the central nervous system (CNS) interprets smells?

    <p>By analyzing the pattern of activity across a range of olfactory receptors. (C)</p> Signup and view all the answers

    What is the primary function of gustation?

    <p>To provide information about foods and liquids. (A)</p> Signup and view all the answers

    Where are taste receptors typically located?

    <p>On the tongue, pharynx, and larynx. (C)</p> Signup and view all the answers

    What is the role of taste hairs in gustation?

    <p>To bind to receptor proteins. (C)</p> Signup and view all the answers

    Which of the following is true regarding taste sensitivity?

    <p>It exhibits significant individual differences, including some that are inherited. (C)</p> Signup and view all the answers

    What is the function of lingual papillae?

    <p>To integrate with taste buds on the tongue. (D)</p> Signup and view all the answers

    What effect does age typically have on the number of olfactory receptors?

    <p>The number declines with age. (B)</p> Signup and view all the answers

    Which structure is the initial site of light refraction in the eye?

    <p>Cornea (C)</p> Signup and view all the answers

    What is the primary function of the ciliary muscle?

    <p>Controlling the shape of the lens for focusing (D)</p> Signup and view all the answers

    What is the main function of the rods in the retina?

    <p>Detecting motion with high sensitivity to low light (D)</p> Signup and view all the answers

    Where is the fovea located within the eye?

    <p>At the region just lateral to the optic disc (B)</p> Signup and view all the answers

    What is the primary cause of glaucoma?

    <p>Damage to the optic nerve, usually due to high intraocular pressure (D)</p> Signup and view all the answers

    What role does the vitreous humor play in the eye?

    <p>Stabilizes eye shape and supports the retina (C)</p> Signup and view all the answers

    What is accommodation, in relation to vision?

    <p>The changing of lens shape to focus images on the retina (B)</p> Signup and view all the answers

    Astigmatism is primarily caused by which of the following?

    <p>An oblong curvature of the cornea (C)</p> Signup and view all the answers

    Which cells in the retina monitor the rods and cones?

    <p>Ganglion cells (B)</p> Signup and view all the answers

    What is the role of the optic radiations in the visual pathway?

    <p>To link the lateral geniculate nucleus with the visual cortex (C)</p> Signup and view all the answers

    Signup and view all the answers

    Study Notes

    The Special Senses

    • Five special senses include olfaction (smell), gustation (taste), vision, equilibrium, and hearing

    • Olfaction (Smell)

      • Olfactory organs provide the sense of smell
      • Located in the nasal cavity, on either side of the nasal septum
      • Made up of two layers: olfactory epithelium and lamina propria
      • Olfactory epithelium contains olfactory receptors, supporting cells, and basal (stem) cells
      • Lamina propria includes areolar tissue, blood vessels, and nerves
      • Olfactory glands secrete substances that coat the surfaces of olfactory organs
      • Olfactory receptors are specialized neurons that detect dissolved chemicals and interact with odorant-binding proteins
      • Olfactory pathways follow axons leaving the olfactory epithelium, collect into bundles, and penetrate the cribriform plate of the ethmoid. They then reach the olfactory bulbs in the cerebrum, where the first synapse occurs. Axons then leave the olfactory bulb, travel along the olfactory tract, and reach the olfactory cortex, hypothalamus, and portions of the limbic system. Arriving information reaches various centers without always first synapsing in the thalamus
      • We can distinguish thousands of chemical stimuli
      • The CNS interprets smells by the pattern of receptor activity
      • There is a considerable turnover of olfactory receptor population
      • Number of olfactory receptors declines with age

    • Gustation (Taste)

      • Gustation provides information about foods and liquids
      • Taste receptors (gustatory receptors) are distributed on the tongue and portions of the pharynx and larynx
      • Clustered into taste buds
      • Taste buds contain basal (stem) cells and gustatory cells
      • Gustatory cells extend taste hairs through taste pores and survive about 10 days before replacement.
      • Dissolved chemicals contact taste hairs, bind to receptor proteins, activate ion channels, stimulation produces depolarization, and release neurotransmitters
      • Neurotransmitters generate action potentials
      • Taste sensitivity exhibits significant individual differences
      • Some conditions are inherited
      • Ex: phenylthiocarbamide (PTC) – 70% of people taste it, but 30% do not
      • Number of taste buds begins declining rapidly by age 50

    • Vision (The Eye)

      • Accessory structures of the eye provide protection, lubrication, and support
      • Including: palpebrae (eyelids), superficial epithelium of the eye, and the lacrimal apparatus
      • Structures of the Eye (1 of 3): palpebrae (eyelids), are continuations of skin
      • Blinking keeps surface of eye lubricated, free of dust and debris
      • Lacrimal caruncle is a soft tissue that contains glands producing thick secretions
      • Generates "sand-like" deposits after sleeping
      • Structures of the Eye (2 of 3): conjunctiva is an epithelium covering the outer surface and inner surface of eyelids
      • Structures of the Eye (3 of 3): lacrimal apparatus produces, distributes and drains tears, lacrimal gland is the "tear gland
      • Secretions contain lysozyme – an antibacterial enzyme
      • Three layers of the eye
      • Outer fibrous tunic including sclera and cornea
      • Middle vascular tunic (also known as the uvea) includes the choroid
      • Inner neural tunic including retina

    • Glaucoma

      • Over time optic nerve becomes damaged, usually due to high intraocular pressure

    • Age-Related Macular Degeneration

      • Deterioration of the macula (location of fovea)

    • The Eye

      • Small anterior segment: aqueous humor
      • Fluid circulates within anterior eye chamber into Canal of Schlemm, re-enters circulation
      • Intraocular pressure
      • Fluid pressure in aqueous humor helps maintain eye shape
      • The lens is the main structure involved in light refraction
      • Bending of light by cornea and lens
      • Focal point - Specific point of intersection on retina
      • Focal distance - Distance between center of lens and focal point
      • Accommodation
      • Shape of lens changes to focus image on retina

    • Visual Abnormalities: myopia, hyperopia, astigmatism

    • Visual Physiology: Photoreceptors

      • Rods respond to almost any photon (they don't discriminate light colors), regardless of energy content
      • Cones- Color vision is the integration of information from red, green, and blue cones. Color blindness is the inability to detect certain colors
      • Central Processing of Visual Information
      • Axons from ganglion cells converge on optic disc
      • Ganglion cells (M cells and P cells) monitor rods and cones
      • Axons penetrate the wall of the eye, proceed as optic nerves, and reach the diencephalon at the optic chiasm
      • Visual data from combined field of vision arrives at the visual cortex of the occipital lobes

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    Related Documents

    Special Senses Lecture Notes PDF

    Description

    Explore the fascinating details of olfaction, one of the five special senses. Understand how the olfactory organs function, their structure, and the pathways that the olfactory signals follow to reach the brain. This quiz will deepen your understanding of the complex mechanisms behind the sense of smell.

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