Dermatology A&P Flashcards
The four types of human tissue.
Muscle Tissue
Nervous Tissue
Epithelial tissue
Connective Tissue
Medical term for skin and main portion of the integumentary system.
Epithelium
Binds organs together
Protects and supports the body and its organs
Stores energy reserves as fat
Provides immunity
Connective Tissue
They provide contact or adhesion between neighboring cells or between a cell and
extracellular matrix.
Cell Junctions
Form barrier against water and antigens passing between individual epithelial
cells.
Tight Junction
Cell-cell adhesions continuously assembled & disassembled so cells can respond changes in their microenvironment.
Ahderens Junctions
Form stable adhesive junctions between cells
Desmosomes
Allows various molecules & electrical signals to pass freely between cells
Gap Junctions
Epithelial tissue is broadly categorized as either
Covering and lining epithelium
Glandular epithelium
most superficial layer of cells
Apical layer
deepest layer of the cells
Basal layer
Thin extracellular structure composed mostly of protein fibers
Located between the epithelium and underlying connective tissue layer
(Helps to bind and support the epithelium
Basement membrane
2 ways of classifying epithelial tissue
Morphology-
based on shape
Stratification-
based on number of layers
4 types of morphology
Squamous, Cuboidal, Columnar, and Transitional
in, flat shape allows rapid passage of substances through them
Found in areas such as the lining of the esophagus, mouth and cervix
Squamous Epithelium
Frequently have microvilli at apical surface
Tall as they are wide and shaped like cubes or hexagons
Found in areas such as the salivary glands and thyroid follicles
Cuboidal Epithelium
Taller than they are wide
Often specialized for secretion and absorption
Lines most organs of the GI tract, respiratory tract, and fallopian tubes
Columnar Epithelium
) Able to change shape from flat to cuboidal and back depending on tension & distention of tissue.
urinary bladder
Transitional Epithelium
A single layer of cells that functions in a diffusion, osmosis, filtration, secretion and
absorption.
Simple epithelium
) It is simple epithelium that appears be stratified because the cell nuclei lie at
different levels and not all cells reach the apical surface.
goblet cells
Pseudostratified epithelium
Cilia provide two forms of locomotion depending on the cell
Ciliated Epithelial Cells
increase the surface area of a cell by multiplying the area from 2 dimensions to 3 dimensions.
Microvilli
A highly-insoluble fibrous protein with water-proofing qualities &high friction resistance.
Keratin
Found on wet/interior surfaces exposed to considerable wear & tear.
Non-keratinized stratified epithelium
Connective tissues typically have three components
(a) Resident Cells
(b) Extracellular Matrix (ECM)
(c) Protein fibers
Most common cells in connective tissue
Fibroblasts
Function in localized release of compounds important to inflammatory response,
innate immunity, and tissue repair
Mast Cells
Abundant (25% of all protein in body)
Key element of all connective tissues,
Collagen Fibers
Have rubberlike properties that allow tissue containing these fibers to be stretched
or distended and return to their original shape.
Elastic fiber
(1) Compromised of glycogen and glycoprotein.
(2) Provide strength and support in the walls of small blood vessels.
(3) Stroma supporting framework of many soft organs; most notably the immune system, liver, endocrine glands, spleen, lymph nodes.
Reticular Fibers
Layers of the epidermis
Stratum Corneum
Stratum Lucidum
Stratum Granulosum
Stratum Spinosum
Stratum Basale
Specialized cells of the epidermis and hair follicle; primary function is to synthesis and transfer melanin to adjacent keratinocytes
Melanocytes
Melanin synthesis occurs in a specialized organelle, the melanosome
Touch and pressure are sensed by four types of mechanoreceptors in the skin
Expanded dendritic endings in epidermis of glabrous skin that
respond to sustained pressure and touch
Consist of tactile disc and neuron for touch sensation
Merkel Cells
Typically found within the stratum spinosum
Form a mobile and dense network of cells that sampling any antigens that attempt to
pass through the epidermis
These monocyte-derived cells represent a large part of the skin’s adaptive immunity.
Dendritic Cells
Derm-specific exocrine glands
Sebaceous
Sudoriferous
An exocrine gland in the skin that opens into a hair follicle and secretes an oily/waxy sebum.
Sebum lubricates the hair in humans and other mammals
Sebaceous Glands
Helps emulsify the sweat produced by the eccrine glands and this
produces a sheet of sweat that is not readily lost in drops of sweat. Helps in
delaying dehydration.
Sebum
Serves as major thermoregulation component of the integumentary system
Cover nearly the entire body surface; especially dense on the palms, soles, forehead,
and upper limbs
Eccrine Glands
Largely confined to the axillae, perineum, and the concentrated in hairy areas
do not become functional until puberty and have a hormonal
activation pattern
Apocrine Glands
Skin & mucous membrane color as diagnostic clues
Blue= Cyanosis (lack of O2)
yellow = Jaundice (Bilirubin)
Red = Erythema (Injury)
Paleness = Pallor (Shock)
Pigments that influence skin pigmentation:
Melanin
Carotene
Hemoglobin
Primary determinant of skin color, hair color and eye color.
Melanin
Melanocytes numbers are approximately the same (with 3-5%) in all people, regardless of their skin tone or Fitzpatrick Scale
What stimulates melanin production?
UV light exposure
The functions of skin
Temperature Regulation
Protection
Cutaneous Sensation
Excretion/Absorption/Synth
Five signs of inflammation
Localized Hyperthermia
Erythema
Localized Edema
Pain
Loss of function
Intrinsic vs extrinsic aging
Intrinsic: The inevitable physiologic changes of the skin that occur with time and are influenced by genetic and hormonal factors.
Extrinsic: The preventable structural & functional changes of the skin that occur with exposure
Most rapidly regenerating and repairing tissue and has capacity for continuous
renewal
Epithelial Tissue
slower than epithelial cells and prone to hyperproliferation
(scarring)
Connective tissue
Poorest capacity for renewal because it does not undergo mitosis to replace damaged neurons
Nervous tissue
Healing – Inflammation Phase
1-3 days post injury
Serves mainly to clear bacteria & debris from the wound and to prepare wound
environment for repair
Healing – Proliferative Phase
2-10 days post injury
Purpose is to construct granulation tissue to fill the defect caused by the wound
Healing – Early Remodeling Phase
2–3 weeks post-injury: tissue defects have been replaced with granulation tissue &
covered by new epithelial cells
Healing – Late Remodeling Phase
months to > 1 year
Healing by Primary Intention
Sutures
Healing by Secondary Intention
Healing within body
