Learning Objectives-Exam 1 Flashcards
describe the physiologic functions of the epidermis (4)
primary protection/physical barrier against microbes, chemicals, toxins, and impacts via formation of the cornified envelope. production of antimicrobial substances, and permanent shedding of corneocytes; is also the primary envelope to contain water, electrolytes, and macromolecules
describe the physiologic functions of the dermis (3)
blood supply, immune protection, anchors epidermis
describe the physiologic functions of the hypodermis/subcutis
anchors the dermis to underlying muscle and bone
describe basic anatomy of the ear and how ear canal, middle, and inner ear relate to each other
- pinna: outer shell, can palpate
- ventral canal connects pinna to horizontal canal (palpation and otoscopy)
- tympanic membrane leads to bony septum leads to inner ear (ventral to middle ear); need to sedate to look at
- middle ear leads to auditory tube
(can only evaluate inner ear and middle ear via CT and MRI)
contrast feline ear to canine ear
In felines, septum bulla (felines have not dogs) almost completely separates tympanic cavity into two compartments (ventromedial and dorsolateral) but this separation is incomplete and not as prominent in canines
describe how the ear canal, middle ear, ad inner ear relate to each other
- pinna: visible from outside and can palpate; elastic cartilage; sweat and sebaceous glands
- vertical canal: should feel pliable and not painful upon palpation
- typmanum: pars tensa, pars flaccida, manubrium of malleus
- pars tensa= thin shiny sheet on ear drum
-manubrium= give conical shape
-pars flaccida= not taut like tensa and hold up membrane - inner ear is embedded in bones, contains
-vestibular organ: semi-circular ducts, balance
-cochlea: hearing
-both above communicate with middle ear through membrane-covered windows - middle ear: boney hollow structure; holds the air-filled tympanic cavity
define the healthy ear and skin microbiome (5)
- the collection of microbes that naturally live on our bodies
- in a constant state of flux
- composition varies based on species, between individuals of the same species, and depending on body site of the same individual
- influenced by many factors
- shifts in our natural microbiome can be caused by inflammation
if a dog’s natural ear microbiome is chronically shifted, what can result?
they can have chronic otitis due to persistent inflammation; allergic dogs have a tendency to develop bacterial otitis; body responds to allergens with inflammation, making a more suitable environment for infection
what are internal impacts to the skin? (2) what can they result in?
- malnutrition
- lack of essential fatty acids
these can cause epidermal lipid deficiency/disturbance and lead to scaling and poor barrier function
what are external impacts to the skin? (3) what can they result in?
- excessive washing
- chemicals
- wet/dry environment
can weaken epidermal barrier, leading to increased scaling and increased transepidermal water loss
describe the process of keratinization (4)
- proliferation/adhesion
- production of additional keratin filaments; beginning of synthesis of lipid-containing lamellar bodies
- progressive flattening of cells, keratin filaments get progressively packed into large, insoluble polymers with the help of filaggrin
- keratinocytes are terminally differentiated, coated by lipids, separated by proteases, and constantly shed
list the phases of the hair follicle cycle (go to hair follicle brainscape and study further too!)
- anagen (growth phase)
- catagen (regression phase)
- telogen (resting phase)
- exogen + anagen
explain the basic anatomy of hooves
keratinized portion of hoof is composed of wall, sole, frog
wall: stratum externum (tubular and intertubular horn), stratum medium (tubular and intertubular horn), stratum internum (lamella), laminar corium (dermis, where primary and secondary epidermal and dermal laminae interdigitate)
sole: similar to tubular and intertubular regions of wall, but softer than wall, has white line
frog: similar to sole but underlying papillae are shorter and frog is softer than sole
contrast integument anatomy of nails, hooves, and horns across species
horses: hoof; wall, sole, frog
ruminants and swine: claws; wall, sole, bulbs (no frog); walls only have primary epidermal and dermal laminae, no secondary
carnivores: claws; wall and sole
explain basic anatomy of horns and nails
- horn is keratinized portion (hard keratin; doesn’t slough off)
- underlying dermis (corium)
- hypodermis may or may not be present; modified to form digital cushion and digital pad
- bones and associated structures of bones
Name, list, and identify the bones related to forelimb (small and large animals).
Name, list, identify, and recognize the bones that make up specific joints of the forelimb (small and large animals).
see other brainscapes for this
Define cutis and subcutis and relate to gross anatomy
cutis: superficial dermis + underlying dermis
subcutis: hypodermis (where sub Q fluids are deposited)
both are outermost layers of the skin
Distinguish between the strata of the epidermis and the layers of the dermis. Describe their interdigitation.
epidermis:
1. stratum corneum: outermost; layers of flat cornified/keratinized. cells lacking a nucleus and organelles; varies in thickness based on abrasion
2. stratum lucidum: clear layer, inconsistent and rare squamous cell layer; found only in very thick epidermal regions
3. stratum granulosum: flattened cells that contain keratohyalin granules (present in soft keratin but NOT in hard keratin)
4. stratum spinosum: prickle cell layer; thick in regions with no hair, thin in regions with hair
5. stratum basale: proliferation and attachment layer; adjacent to dermis; cell division occurs here
dermis/corium: network of collagen, elastic, reticular fibers
1. papillary layer: loose irregular CT; most superficial layers; interdigitates with s. basale via dermal papillae
2. reticular layer: dense irregular CT; deepest and thickest layer; many large bundles of collagenous fibers
Distinguish between keratinocytes and non-keratinocytes
keratinocytes: most numerous cell type of epidermis; maturation process is kertinization
non-keratinocytes: include melanocytes (produce pigment, cytocrine secretion), intraepidermal macrophages/Langerhan’s cells (dendritic cells in upper stratum spinosum), and tactile epithelioid cells/Merkel cells (sensory mechanoreceptors in basement membrane of s. basale)
Distinguish between the layers of the hair
hair is subdivided into shaft, root, and hair bulb; shaft has 3 layers
1. cuticle: outermost single layer of overlapping (shingle-like) keratinized cells
2. cortex: densely packed keratinized cells that contain pigment granules
3. medulla: center of hair, loosely arranged cuboidal or flattened cells
distinguish between the layers of the hair follicle (6)
- internal epithelial root sheath: innermost layer next to hair root/stratum corneum of hair follicle
- external epithelial root sheath: strata basale and spinosum of hair follicle
- glassy membrane: basement membrane of follicle epithelium
- dermal root sheath and dermal papilla: CT enclosure of hair follicle; root sheath continuous with papilla that projects into underside/base of bulb; made of collagen and elastic fibers, blood vessels, nerves
- hair matrix: dividing cells (s. basale) overlying dermal papilla, product the hard keratin = hair
- arrector pili muscle: smooth muscle, innervated by ANS; spans dermal root sheath of follicle and papillary layer of dermis; elevates hair and expresses sebaceous glands located between follicle and muscle mass
Distinguish between sebaceous and sudoriferous glands and know their modes of secretion/what they produce
sebaceous glands: alveolar, holocrine secretion, secrete sebum; secrete product into hair follicle or directly onto skin surface
sweat glands/sudoriferous glands: produce sudor/sweat; vary greatly in appearance and secretory product; utilize merocrine and apocrine secretion; include mammary glands, anal glands
Determine the type of cartilage that supports the pinna
elastic cartilage
Define cerumen and list the glands that contribute to its formation
cerumen: the combo of sebaceous and ceruminous gland secretions known as ear wax; ceruminous glands are simple coiled tubular apocrine sweat glands of inner surface of ear pinna and external auditory canal