Integumentary System Flashcards
Epidermis
Keratinized stratified squamous epithelium that grows continuously grows. Derived from ectoderm
Dermis
Connective tissue that provides support for the skin. Contains epidermal appendages, blood vessels, and nerves. Derived from mesoderm
Hypodermis
Variable amount of adipose tissue. Main function is insulation.
Principle cells of epidermis
Keratinocytes
Stratum basale
Deepest layer of epidermis. Single layer of cells on the basement membrane. Contains mitotically active cells.
Hemidesmosomes
Link keratinocytes of stratum basale to basal lamina
Blistering diseases
Autoimmune reactions to hemidesmosomes
Stratum spinosum
Several cells thick. Connected by desmosomes. Cells are generally spherical in shape.
Stratum Granulosum
Contains keratohyalin granules that stains intensely.
Stratum lucidum
Contains most differentiated cells in the epidermis. Lost nucleus and cytoplasmic organelles.
Main functions of keratinocytes
Produce keratin and for water barrier.
2 unique structures found in keratinocytes
Keratohyalin granules and lamellar bodies
Main proteins in keratohyalin granules
Filaggrin and trichohyalin. Promote aggregation of keratin filaments into fibrils
Keratinization
Aggregation of keratin filaments into fibrils.
Lamellar bodies
Membrane-bound vesicles that contain a mixture of lipids (make the water barrier)
Where are squamous cell carcinomas derived from?
Stratum spinosum
Which layer is basal cell carcinoma derived from?
Stratum basale
Melanocytes-function
Production and distribution of melanin
Melanocytes-cell structuree
Rounded cell body, numerous long processes. Not bound by desmosomes. Contain melanosomes.
Melanosomes
Granules of melanin
Malignant melanoma
Malignant tumor of melanocytes
Langerhans’ cells
Monocyte-derived immune system cells in the epidermis. Antigen-presenting cells that illicit an immune response when pathogens enter the skin. “Gather” antigens then present them to lymph nodes, and thus lymphocytes.
Dendritic cell found in the epidermis not bound by desmosomes
Langerhans’ cells
Merkel’s cells
Mechanoreception. Make contact with sensory nerve fibers. Most abundant in the fingertips. Located in stratum basale (bound via desmosomes). Have dense-core granules in the cytoplasm.
Junction between dermis and epidermis
Rete Ridges (epideermis) Dermal papillae (dermis)
Layers of the dermis
Papillary layer
Reticular layer
Papillary layer of the dermis
Loose connective tissue. More superficial. Includes dermal papillae
Reticular layer of dermis
Deep to papillary. More thick and less cellular. Dense irregular connective tissue.
Capillary Loops
In the dermal papillae. Give skin the pink color.
Superficial Vascular plexus
Found at the junction between the papillary and reticular layers
Deep vascular plexus
Located at the cutaneous/subcutaneous junction
Where are lymphatic capillaries usually found?
Dermal papillae
Pilosebaceous apparatus
Hair follicles, hair and sebaceous glands
Root of a hair
Part of the hair located in the follicle
Shaft of hair
Any part that projects above the surface of the epidermis
Innermost layer of hair
Medulla
Layer of hair that contains live cells accumulating keratin
Cortex
Outer most layer of hair consisting of dead squamous cells
Cuticle
What do sebaceous glands secrete? (General term)
Sebum
Appearance of mature cells in sebaceous glands
Abundant SER, lipid droplets. Undergo apoptosis once released
Arrector pili muscle
Smooth muscle at connects the deeper part of the follicle to the superficial dermis. Causes erection of hair. Innervated via sympathetic nervous system.
Appearance of eccrine sweat glands
Simple coiled tubular glands. Not associated with hair follicle. Duct is lined with stratified cuboidal epithelium.
What produces thee watery component of sweat?
Clear cells of eccrine sweat glands
Appearance of dark eccrine sweat gland cells
Abundant RER and glycoprotein granules
What secretes the proteinaceous component of sweat?
Dark cells of eccrine sweat glands
What produces contractions that helps discharge sweat into ducts?
Myoepithelial cells
Apocrine sweat glands
Large-lumen tubular glands associated with hair follicles
Which gland secretes pheromones?
Apocrine sweat glands
Mammary glands
Modified apocrine sweat glands
What initiates secretion in mammary glands?
Prolactin
What stimulates ejection of milk from the breast?
Oxytocin
What cells released oxytocin in mammary glands?
Myoepithelial cells between secretory cells and basal lamina.
Branched tubuloalveolar glands
Make up each lobule of mammary glands (along with dense irregular connective tissue).
Lactiferous sinuses
Ducts of the tubuloavleolar glands that are lined with stratified cuboidal epithelium
What do inactive tubuloalveolar glands lack?
Secretory end-pieces
What types of secretion are involved with the production of milk?
Merocrine and apocrine
What part of the milk is synthesized via merocrine secretion?
The proteinaceous part
What part of milk if formed via apocrine secretion?
Fatty component of milk
