Structure & Function Flashcards
Full structure of the skin:
Divided into epidermis, dermis, and subcutaneous tissue
Epidermis layers:
5 major layers of ____. As you go from bottom to top, the cells get ___ and more ____.
Keratinocytes
Older
Differentiated
___ ___ layer no longer has a nucleus. It is the toughest layer and the most full of keratin, proteins, and lipids
Stratum corneum
Skin tissue is ____ ___ epithelium
Stratified squamous
Histology of epidermis:
The ___ ___ layer is rapidly proliferating stem cells and can be seen in this picture with melanin.
Basal cell
____ ____ has a somewhat spiny appearance. It is multiple cells thick. Creating keratin filaments. Creating other proteins that will pack the filaments into bundles called tonofibrils.
Stratum Spinosum
___ ___ is a more flat layer packed with keratin tonofibrils, keratohyaline granules, lamellar bodies.
Seen in the dark cell layer in the picture below.
Stratum granulosum
In the stratum granulosum, ___ becomes ___ which is connected to lipids and prevents water loss.
Profilaggrin
Filaggrin
___ ___ is not seen in every picture of the skin. It is only present in really thick skin such as on the heel or the palms. No nuclei, clear.
Stratum lucidum
____ ___ is a layer of keratinized cells without nuclei that are about to be sloughed off. Elongated and skinny cells.
Stratum corneum.
It takes ___ days for a cell to travel from the basal lamina to the stratum corneum to be sloughed off
28
Table:
____ connect cells to the basement membrane
Hemidesmosomes
Proteins and connectors:
Cytokerstin filaments become more abundant as you go from the basal lamina to stratum spinosum. they pack together to form ___ ___ and then placed into ___ ___.
Keratin tonofibrils
Lamellar bodies
Hemidesmosome connects the ___ to the basement membrane and ____.
Epidermis
Dermis
___ ___ is a condition where the patient has antibodies to portions of hemidesmosomes, leading to tense vesicles and Bullae. Tense meaning the vesicles are in between the ___ and ___.
Bulbous pemphigoid
Dermis
Epidermis
____ are cell to cell connections. They anchor the cytoskeleton.
Desmosomes
____ ___ is an autoimmune disease with antibodies to portion of the desmosomes, leading to flaccid vesicles and bullae. Keratinocytes pull apart from each other. The basal membrane is still intact.
Pemphigus vulgaris
_____ is the loss of cell to cell adhesion, resulting in flaccid vesicles.
Acantholysis
_____ are derived from neural crest cells. They produce packed pigment into melanosomes for the keratinocytes.
Melanocytes
___ ___ are mechanoreceptors essential for sensing light touch and are located in the basal layer. They also release ___ and _____ when activated
Merkel cells
Serotonin
Neuropeptides
___ ___ are immunosurveillance cells, derived from monocytes, present antigens to T cells
Langerhans cells
Dermis contains:
Ground substance, collagen, elastic fibers, glands, hair follicles, somatic sensory and sympathetic autonomic nerves, blood vessels, lymphatics, Pacinian corpuscles
Hypodermis (subcutaneous) contains:
Adipose tissue, (not technically part of the skin, but is important to the skin)
The dermis has a ____, ___ border due to dermal papillae and epidermal pegs/ridges.
Wavy
Irregular
Dermis division:
____ layer contains loose connective tissue, type one and type three collagen, fibroblasts, mast cells, dendritic cells, and type seven collagen.
____ layer contains dense, irregular connective, tissue and elastic fibers
Papillary
Particular
Picture of reticular layer stained for elastic fibers:
Important accessory structures in the dermis:
___ Sweat glands extend from the skin surface down into the dermis. They are located all over the skin. They perform thermal regulation. They are innervated by ___ ___.
Eccrine
Cholinergic fibers
____ sweat glands are located in auxiliary and perineal regions. They open into hair follicles. Develop in response to sex hormones. Innervated by ___ ___.
Apocrine
Adrenergic fibers
___ ___ are found in just under the upper dermis, especially in fingertips, palms and soles and sense light touch
___ ___ are deeper in the dermis and hypodermis. They detect vibration and pressure.
Meissner’s
Pacinian
Blood vessels:
___ ___ provides nutrients to the epidermidis. ___ ___ is lower in the dermis and into the subcutaneous layer. Both participate in thermal regulation with ____ ___ of blood flow, depending on the needs of the body
Subpapillary plexus
Deep plexus
Ateriovenous shunting
Keratinization:
Desmoglein 3 and 1
Review:
____ (dry skin) is a condition that affects the stratum corneum, reducing its ability to retain moisture, and leading to scaly itching, and sometimes inflammation
Xerosis
___ ____ (eczema) involves the stratum corneum. A defective skin barrier allows allergens to penetrate the skin leading to itching and inflammation
Atopic dermatitis
Atopic dermatitis also results and disrupted ___ ___ ___. Mutation in the gene encoding ____ have been identified as a risk factor for the development of a subset of atopic dermatitis
Epidermal water barrier
filaggrin (FLG)
Atopic dermatitis:
____ of the stratum spinosum give this layer its spiny or prickle cell appearance. Numerous enter collating, cytoplasmic processes (spines) how old are together by desmosomes.
Desmosomes
Desmosomes interact with ___, and intermediate filament. Other adhesion proteins involved in desmosomes are ___, ____, ____, and ___.
Keratins
Desmocollin
Desmoglein
Plactoglobin
Desmoplakin
Hemidesmosomes link ___ ___ of epithelial cells to laminin in the basal lamina. Adhesion proteins ___ and ___.
Intermediate filaments
Integrin
Collagen XVII
Stratum granulosum:
_____ granules are masses of Filaggrin and trichohyalin. They promote aggregation of ____ filaments into course bundles called ___.
Keratohyalin
Keratin
Tonofibrils
What are the physical and molecular features that support the epidermal-dermal attachment?
___ and ___ are adapter protein components of the hemi desmosomes, which make connections with the keratin filaments
Dystonin
Plectin
____ ____ ___: caused by defects in laminin and collagen XVII resulting in the detachment of basal cells from basal lamina. Blistering
Junctional Epidermolysis Bullosa
___ ___ ___: caused by defects in type VII collagen (anchoring fibrils) resulting
In the detachment of the basal lamina from the lamina reticularis. Blistering
Dystrophic Epidermolysis Bullosa
____ ___ are at sites of mechanical stress. In thick skin, the mitotic basal surface of the epidermis greatly exceeds its free surface. As a result, more cells per unit time enter stratum cornea in ___ versus ___ skin.
Epidermal pegs
Thick
Thin
___ ___ is a blistering skin disease that occurs most commonly and elderly individuals. It is an auto immune disorder characterized by antibodies against the hemidesmosomal proteins.
Bullous pemphigoid
Skin cell types:
Interdigitating ___ ___ and ___ ___ reinforce the dermal-epidermal Junction
Dermal papillae
Epidermal pegs
Eccrine sweat gland secretions are primarily composed of ___ and ions such as __, __, and ___. Apocrine sweat gland secretions are more ___.
Water
Na, Cl, and K
Viscous
The ___ ___ of sweat glands reabsorbs ions to prevent excessive loss. Degree of reabsorption depends on rate of sweat production
Duct segment
___ ___ of sweat glands contain clear cells that secrets ___ ___, dark cells that secrete ___ and ___, and Myoepithelial cells that surround secretory portions and ___ to move secretions into the ducts.
Secretory segment
Interstitial fluid
Mucins and dermcidin
Contract
___ ___ is a few spiraling dendrites, surrounded by Schwann cells and a connective tissue capsule. Located in dermal papillae. Sense light touch.
Meissner’s corpuscle
____ ____ is a single dendrite surrounded by multiple layers of cellular lamellae separated by fluid filled spaces. Located in deep dermis and hypodermis. Sense pressure and vibration.
Pacinian corpuscle
Papillary dermis versus reticular dermis:
C. Filaggrin
Present antigen to T cells
A
C
