Integument Physiology II Flashcards
Thickness of skin layers (from thickest to thinnest).
Hypodermis, dermis, epidermis
Pneumonic for layers of epidermis?
Come Get Sun Burnt
List four layers of epidermis? Innermost to outermost?
Stratum basale, stratum spinosum, stratum granulosum, stratum corneum
How many layers in stratum basale? Types of cells? Most common type of cell? Movement?
Single layer; columnar to cubiodal cells; keratinocytes; upwards to replenish epidermis
Main functions of stratum basale?
- Anchor epidermis to dermis
- Proliferative and reparative (stem cell function)
What is another name for the stratum spinosum?
Prickle cell layer
Composition of SS?
Daughter cells of SB
How many layers in SS?
1-2 layers thick
Why is the SS also called prickle cell layer?
keratinocytes are also connected by intercellular bridges or prickles
What does the stratum spinosum synthesize?
lamellar granules (glycoproteins, glycolipids, phospholipids)
Function of lamellar granules?
barrier function
Composition of SG?
SS and SS daughter cells
Three substances in SG?
Pilofilaggrin, keratin filaments, loricin
SG thickness in haired vs non haired regions?
1-2 cells thick; 4-8 cells thick
Cell shape and color of SG?
Flattened and basophilic (blue)
What are filaggrin degradation products responsible for?
SC hydration and UV light barrier
SG nuclei size and substance in cytoplasm?
small, keratohyalin granules
Keratinocytes are constantly being ____ in SC.
shed
Cell shape of corneocytes, nuclei composition, and type of cell in SC?
flattened, anuclear cells, eosinophilic
Where are corneocytes located in the SC?
multilayered zone suspended in extracellular lipid matrix
How often do dogs replace their epidermal layer?
Every 20-25 days
What do corneocytes contain?
Humectants/sunscreens
What are adnexa?
Structures of the skin
What maintains epidermal thickness?
Proliferation of basal cells
What is the function of the cornified envelope?
Structural support to the cell and resists invasion
In hairless areas, hair follicles include ___________ __________.
mucocutaneous junctions
Describe simple vs compound hair follicles. Example of species of each.
Simple: single hair from one orifice Ex. Pig, horse
Compound: Multiple hairs from one orifice Ex. dogs, cats, sheep
Describe primary vs. secondary hair shafts.
Larger “guard hairs”
Smaller “undercoat”
What are tactile hairs, what are they surrounded by and function?
Large, simple hair
Surrounded by blood sinus
Sensory
Describe the anatomy of a follicle (3 parts)
Infundibulum: Superficial part
Isthmus: middle part, arrector pili m. attachment
Inferior: deepest, produces shaft (anagen), holds during rest (telogen)
What do sebaceous glands produce?
sebum- oily secretion
What do sebaceous glands combine with to form?
Combines with sweat to create hydration and chemical barrier
Where do sweat glands open up into?
superficial portion of hair follicle
What are sweat glands lined with?
Epithelium and contractile myoepithelial cells
Where do sebaceous glands open into on hair follicles? Some open up where?
deep portion of infundibulum; open on surface of the skin
Difference between apocrine and eccrine glands?
Apocrine: on the hair follicle
Eccrine: NOT on the hair follicle, open on the epidermal surface, tubular
What are the four stages of the hair cycle?
- Anagen
- Catagen
- Telogen
- Exogen
Provide one word association with each of the hair cycles. (Anagen, catagen, telogen, exogen)
Anagen: Growth
Catagen: Regression
Telogen: Resting
Exogen: Shedding
Where does cyclic activity primarily occur?
Below the insertion of arrector pili m. of hair follicle
What does the duration of phase depend on?
age
region
breed
sex
physio/path factors
What is the hair cycle controlled by?
Photoperiod
Ambient
Temp
Nutrition
Hormones
Overall Health
Genetics
