Pathology: Eye + Ear
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Questions and Answers

What is the outer layer of the cornea composed of?

  • Stratified columnar epithelium
  • Simple squamous epithelium
  • Cuboidal epithelium
  • Stratified squamous epithelium (correct)

    • The retina is considered to be an outpouching of brain tissue.

    True (A)

    What is produced by the ciliary body in the eye?

    Aqueous humour

    Glaucoma is characterized by an increase in intraocular fluid ______.

    <p>pressure</p> Signup and view all the answers

    Match the ocular structures with their functions:

    <p>Cornea = Outer protective layer Lens = Focuses light onto the retina Retina = Processes visual information Ciliary body = Produces aqueous humour</p> Signup and view all the answers

    What are the components of the uvea?

    <p>Iris, ciliary body, and choroid (D)</p> Signup and view all the answers

    Descending membrane is a part of the iris structure.

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

    What is the potential cause of secondary glaucoma in veterinary species?

    <p>Another disease process</p> Signup and view all the answers

    Which type of neoplasm is most commonly seen in the pinna of dogs?

    <p>Cutaneous histiocytoma (D)</p> Signup and view all the answers

    Squamous cell carcinoma is most frequently reported in the pinna of grey cats.

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

    What type of polyp is commonly found in cats and originates in the middle ear or Eustachian tube?

    <p>Nasopharyngeal polyps</p> Signup and view all the answers

    Ceruminous adenomas are primarily regarded as ______ in dogs.

    <p>benign</p> Signup and view all the answers

    Match the following types of neoplasms with their characteristics:

    <p>Ceruminous adenoma = Well differentiated tubular cystic mass Squamous cell carcinoma = Common in white cats Cutaneous histiocytoma = Common in the pinna of dogs Nasopharyngeal polyps = Composed of loose connective tissue with small blood vessels</p> Signup and view all the answers

    Which type of glaucoma has no visible abnormalities in the trabecular meshwork?

    <p>Primary open-angle glaucoma (A)</p> Signup and view all the answers

    Entropion is a condition where the eyelid margin is everted.

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

    What is the most common eyelid neoplasm in dogs?

    <p>Meibomian adenoma</p> Signup and view all the answers

    _________ refers to the enlargement of the eye due to increased intraocular pressure.

    <p>Buphthalmia</p> Signup and view all the answers

    Match the following diseases with their characteristics:

    <p>Primary open-angle glaucoma = No visible abnormalities in the trabecular meshwork Entropion = Inversion of the eyelid margin Meibomian adenoma = Most common eyelid neoplasm in dogs Conjunctivitis = Commonly associated with infectious pathogens in cats</p> Signup and view all the answers

    What condition results from misdirected hairs of the eyelids?

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

    Melanoma in eyelids of dogs is usually malignant.

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

    What is the common cause of corneal ulceration?

    <p>Damage to the corneal epithelium</p> Signup and view all the answers

    The term '_________' should not be used synonymously with conjunctivitis.

    <p>conjunctival hyperaemia</p> Signup and view all the answers

    Match the following causes of glaucoma with their descriptions:

    <p>Lens luxation = A type of secondary glaucoma Ciliary cleft closure = Obstructs aqueous outflow Pre-iridal fibrovascular membranes = Can result in secondary glaucoma Diffuse iris melanoma = Common cause of glaucoma in cats</p> Signup and view all the answers

    Which condition is characterized by eversion of the eyelid margin?

    <p>Ectropion (A)</p> Signup and view all the answers

    Adenomas are malignant tumors found in the Meibomian glands of dogs.

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

    What is the most common cause of conjunctivitis in cats?

    <p>Feline herpesvirus (FHV-1)</p> Signup and view all the answers

    ______, a condition characterized by the proliferation of the gland of the nictitating membrane, is commonly referred to as 'cherry eye'.

    <p>Prolapse</p> Signup and view all the answers

    Which type of eyelid entropion is caused by spasm of the orbicularis oculi muscle?

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

    What is the primary cause of otitis externa in dogs?

    <p>Increased moisture and inadequate air circulation within the ear canal (C)</p> Signup and view all the answers

    Ciliary body tumors are more common in cats than in dogs.

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

    What is the term for the accumulation of neutrophils and fibrin in the anterior chamber?

    <p>Hypopyon</p> Signup and view all the answers

    The __________ membrane is a layer of granulation tissue on the anterior surface of the iris.

    <p>preiridal fibrovascular</p> Signup and view all the answers

    Match the ear disorders with their characteristics:

    <p>Otitis externa = Common disorder in dogs and cats Otitis media = Inflammation of the tympanic cavity Otitis interna = Associated with vestibular dysfunction Vestibular dysfunction = Head tilt and ataxia</p> Signup and view all the answers

    What anatomical structure connects the tympanic cavity with the nasopharynx?

    <p>Eustachian tube (B)</p> Signup and view all the answers

    Feline primary ocular sarcoma is common and occurs in both dogs and cats.

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

    What is the main function of hair cells in the inner ear?

    <p>To transduce mechanical stimuli into action potentials.</p> Signup and view all the answers

    Accumulation of blood in the anterior chamber is called __________.

    <p>hyphema</p> Signup and view all the answers

    What type of neoplasms arise from the ciliary body?

    <p>Epithelial (A)</p> Signup and view all the answers

    Chemosis refers to conjunctival swelling.

    <p>True (A)</p> Signup and view all the answers

    What are the consequences of chronic otitis media?

    <p>Lysis of ossicles, spread to the inner ear or brainstem.</p> Signup and view all the answers

    The __________ apparatus in the inner ear contributes to balance.

    <p>vestibular</p> Signup and view all the answers

    Match the types of ear mites with their hosts:

    <p>Otodectes cynotis = Cats Psoroptes cuniculi = Rabbits Otobius magnini = Pigs Raillietia auris = Cattle</p> Signup and view all the answers

    What is a descemetocele?

    <p>A bulge of Descemet's membrane through a corneal ulcer (B)</p> Signup and view all the answers

    Corneal pigmentation is only associated with corneal vascularization.

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

    What is the primary cause of eosinophilic keratitis?

    <p>It is unique to cats and horses and is characterized by non-painful pink-red raised lesions.</p> Signup and view all the answers

    Corneal oedema can be focal, usually caused by a __________, or diffuse, generally due to endothelial damage.

    <p>corneal ulcer</p> Signup and view all the answers

    Match the ocular diseases with their corresponding characteristics:

    <p>Eosinophilic Keratitis = Non-painful pink-red lesions Equine recurrent uveitis = Most common cause of blindness in horses Nodular granulomatous episcleritis = Smooth grey-pink nodule Cataracts = Common disorder of the lens</p> Signup and view all the answers

    Which breed is predisposed to chronic superficial keratitis (pannus)?

    <p>German Shepherd (B)</p> Signup and view all the answers

    Chronic superficial keratitis primarily affects the anterior uvea.

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

    What complication may arise from uveitis?

    <p>Adhesions of iris to cornea or lens, glaucoma, or cataracts.</p> Signup and view all the answers

    Uveal melanoma is most commonly found in the __________.

    <p>canine eye</p> Signup and view all the answers

    Match the condition with its associated risk or cause:

    <p>Corneal sequestrum = Severe corneal damage in cats Lens induced uveitis = Secondary to lens rupture Glaucoma = Closure of the drainage angle Corneal neoplasia = High sun exposure</p> Signup and view all the answers

    What does corneal oedema indicate?

    <p>Injury to corneal epithelium or endothelium (C)</p> Signup and view all the answers

    Lymphoma may cause diffuse thickening of the iris.

    <p>True (A)</p> Signup and view all the answers

    What is the main consequence of lens rupture?

    <p>Inflammation known as phacoclastic uveitis.</p> Signup and view all the answers

    Equine recurrent uveitis is thought to be an __________ disease.

    <p>immune-mediated</p> Signup and view all the answers

    What can lead to the development of cataracts?

    <p>All of the above (D)</p> Signup and view all the answers

    Study Notes

    Anatomy and Histology of the Eye

    • The eye comprises various structures; understanding normal anatomy is essential for diagnosing diseases.
    • Macroscopic evaluation includes the globe, eyelids, Meibomian glands, conjunctiva, third eyelid, lacrimal glands, and extraocular muscles.
    • The cornea consists of an outer stratified squamous epithelium, avascular stroma, and endothelial layer with Descemet's membrane.
    • The uvea includes the iris, ciliary body, and choroid, contributing to vascular support.
    • The lens is biconvex, avascular, and anchored by zonular fibers.
    • The retina, an outpouching of brain tissue, features three layers of neurons and is crucial for vision.
    • Aqueous humor production occurs in the ciliary body, flowing through the pupil to the trabecular meshwork, contributing to intraocular pressure regulation.
    • The blood-eye barrier protects internal structures from immune system exposure.

    Postmortem Examination of the Eye

    • Rapid postmortem changes necessitate immediate fixation in formalin, Bouin’s, or Davidson’s solution for quality histologic sections.
    • Ocular tissues, especially the retina, are highly sensitive to anoxia; mishandling can impair diagnostic efforts.

    Diseases of the Globe

    • Glaucoma: Characterized by increased intraocular pressure, leading to vision loss and blindness; classified as primary or secondary.
    • Primary Glaucoma:
      • Goniodysgenesis: Maldevelopment of the filtration angle, prevalent in purebred dogs.
      • Primary open-angle glaucoma: No visible trabecular meshwork abnormalities, common in laboratory Beagles.
    • Secondary Glaucoma: Caused by obstructions like lens luxation, synechiae, or neoplasia.
    • Pathologic changes from increased intraocular pressure primarily affect the optic nerve and retina, leading to retinal and optic nerve atrophy, ganglion cell death, buphthalmia, and corneal changes.

    Diseases of the Eyelids and Ocular Adnexa

    • Entropion: Eyelid inversion that may cause secondary trichiasis; classified into primary, spastic, and cicatricial types.
    • Ectropion: Eyelid eversion, presenting with conjunctival visualization, hyperemia, and keratitis.
    • Distichiasis and Trichiasis: Eyelash abnormalities that may necessitate treatment if causing corneal irritation.
    • Neoplastic eyelid diseases include:
      • Meibomian adenomas: Common benign tumors in dogs.
      • Melanomas: Typically benign in dogs, but more aggressive in cats.
      • Squamous cell carcinoma: Most common in cats, locally invasive, with metastatic potential.

    Diseases of the Conjunctiva

    • Conjunctival hyperemia: A response to various local and systemic conditions, not synonymous with conjunctivitis.
    • Conjunctivitis: Rare in dogs, often linked to allergies or irritation; common in cats and associated with infectious agents like Herpesvirus and Chlamydia.

    Nictitating Membrane and Corneal Diseases

    • Prolapse of the gland of the nictitating membrane (“cherry eye”): Associated with weak connective tissue in certain breeds.
    • Corneal diseases include keratitis, erosion, ulceration, and associated complications such as vascularization and pigmentation.
    • Melting corneal ulcers lead to progressive corneal tissue loss and may create descemetoceles.

    Diseases of the Sclera and Uveal Tract

    • Nodular granulomatous episcleritis: Common proliferative lesion mistaken for neoplasia.
    • Uveitis: Inflammation of the uvea, classified into anterior (iritis) and posterior (choroiditis) types; can cause complications like synechiae and glaucoma.
    • Equine recurrent uveitis: Major blindness cause in horses, proposed to be immune-mediated.

    Lens and Neoplastic Diseases

    • Cataracts: Most significant lens disorder, can occur secondary to various conditions; characterized by denatured lens protein deposits.
    • Uveal melanoma: Most common intraocular neoplasm, benign in dogs, potentially malignant in cats.
    • Lymphoma and ciliary body tumors can affect intraocular structures.

    Other Eye Terminology

    • Aqueous flare: Increased protein in aqueous humor; Chemosis: conjunctival swelling; Hypopyon: neutrophil accumulation in the anterior chamber; Hyphema: anterior chamber hemorrhage; Iris bombe: anterior iris bowing; Phthisis bulbi: end-stage globe.

    Anatomy and Physiology of the Ear

    • The ear consists of three parts: external, middle, and inner ear, each with specific roles in hearing and balance.
    • The external ear includes the auricle and auditory canal lined with sebaceous and ceruminous glands.

    Diseases of the Ear

    • Otitis externa: Common in dogs and cats, involving moisture and microbial infection; results in complex pathogenesis including chronic changes.
    • Otitis media: Bacterial inflammation of the tympanic cavity; can lead to severe complications if untreated.

    Diseases of the Middle Ear

    • Bacterial organisms, such as Mycoplasma bovis and Pasteurella multocida, often cause otitis media in cattle with potential for systemic involvement.### Otitis Media in Animals
    • Calves: Escherichia coli can cause sporadic otitis media cases.
    • Dogs and Cats: Often linked to chronic otitis externa; in Cavalier King Charles spaniels, primary secretory otitis media is common.
    • Inflammatory Polyps: These may develop in the middle ear, particularly with otitis media in dogs.
    • Cats with Cryptococcosis: Otitis media associated with vestibular disease may be a primary clinical complaint.

    Otitis Media in Specific Animals

    • Pigs: Unilateral otitis media can occur, associated with pathogens like haemolytic Streptococcus, Actinobacillus pleuropneumoniae, and Mycoplasma hyorhinis.
    • Horses: Often not related to otitis externa; can lead to temporohyoid osteoarthropathy and has instances of mycotic otitis media.

    Diseases of the Inner Ear

    • Otitis Interna: Frequently arises from middle ear inflammation; leads to vestibular dysfunction; may progress to suppurative meningitis and encephalitis.
    • Vestibular Dysfunction Signs: Includes head tilt, falling toward the affected side, ataxia, and nystagmus.
    • Causes: Can be due to otitis media, trauma, drugs, and neoplasia. Idiopathic vestibular disease noted in older dogs and cats, characterized by sudden onset and rapid remission without identifiable lesions.

    Neoplasia of the Ear

    • General: Ear neoplasms resemble skin tumors; primary tumours of ceruminous glands and auditory epithelium are rare.
    • Cutaneous Histiocytoma: Commonly found in the pinna of dogs.
    • Squamous Cell Carcinoma: Frequently seen in the pinna of white cats and sheep exposed to UV light.
    • Ceruminous Adenoma/Adenocarcinoma: Common in dogs (mostly benign) and in both benign and malignant forms in cats; adenomas characterized by well-differentiated tubular cystic mass.
    • Nasopharyngeal Polyps: Predominantly in cats; consist of loose connective tissue with small blood vessels, covered by ciliated columnar epithelium; origin is unknown, typically from the middle ear or Eustachian tube.
    • Inflammatory Polyps: Observed in dogs with chronic otitis externa; histologically reveal hyperplastic surface epithelium and leukocytic inflammation.

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    Test your knowledge about the various structures and functions of the eye in this quiz. Explore topics such as the cornea, retina, and uvea, and understand how they contribute to vision. This quiz will help solidify your understanding of ocular anatomy and their respective functions.

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