Derm-Dr. Houston (exam 3) Flashcards
- What is tissue?
- What are the four primary tissues?
Tissue: A group of similar cells and cell products working together to perform a specific role in an organ.
The four primary tissues:
* Epithelial
* Connective
* Nervous
* Muscular
What is the purpose of nervous, muscle, epithelial and connective tissue?
The four primary tissues differ from each other in (3)
What is the matrix (extracellular material) composed of? (2)
The four primary tissues differ from each other in:
* Types and functions of their cells
* Characteristics of the matrix (a.k.a tissue fluid/gel, extracellular fluid/material, interstitial fluid)
* Relative amount of space occupied by cells versus matrix
Matrix (extracellular material) is composed of:
* Clear gel called ground substance
* Fibrous proteins
What are the three types of fibers and their characteristics?
Collagen
* Strongest and most abundant type
* Provides high tensile strength
Elastic
* Networks of long, thin, elastin fibers that allow for stretch
Reticular
* Short, fine, highly branched collagenous fibers
Epithelial tissue
* What are the main two types by location?
Covering and lining epithelia
* On external and internal surfaces
Glandular epithelia
* Secretory tissue in glands
Characteristics of Epithelial cells:
* What is the polarity?
* Composed of what?
* Supported by what?
* Vascular? Nerves?
* High rate of what?
What are the cutanous, serous and mucous membranes?
What is a gland? Usually composed of what?
A cell or organ that secretes substances for use elsewhere in the body or releases them for elimination from the body
* Usually composed of epithelial tissue in a connective tissue framework
What are exocrine glands? Surfaces can be what?
Exocrine glands — maintain their contact with surface of epithelium by way of a duct
* Surfaces can be external (examples: sweat, tear glands) or internal (examples: pancreas, salivary glands)
- What are endocrine glands? What are hormones?
- What are examples?
- Endocrine glands — secrete hormones directly into blood
- Hormones: chemical messengers that stimulate cells elsewhere in the body
- Examples: thyroid, adrenal, and pituitary glands
What is the most widespread epithelium in the body?
Stratified squamous
Stratified Epithelia:
Deepest layers undergo what? How?
Deepest layers undergo continuous mitosis:
* Daughter cells push toward the surface and become flatter as they migrate upward
* Finally die and flake off (exfoliation or desquamation)
What are the two kinds of stratified squamous epithelia?
- Keratinized — found on skin surface, abrasion resistant
- Nonkeratinized — lacks surface layer of dead cells
Keratinized Stratified Squamous Epithelium
* What are the characteristics?
* Resist and retards what/
* Where are the locations?
- Multiple cell layers; cells become flat and scaly toward surface
- Resists abrasion; retards water loss through skin; resists penetration by pathogenic organisms
- Locations: epidermis; palms and soles heavily keratinized
Cotton candy, lacey purple top layer
Non-keratinized Stratified Squamous Epithelium
* Similar to what?
* Resist what?
* What are the locations?
- Same as keratinized epithelium without surface layer of dead cells
- Resists abrasion and penetration of pathogens
- Locations: tongue, oral mucosa, esophagus, and vagina
What are the different types of loose CT? What are the different dense CT?
* What are the characteristics of both
- What are the different cartilages?
- What is the bone tissue?
- What is the liquid CT?
Cartilage?
What are the cells of cartilage? Dense what? Why is there very little repair?
- Cells = “chondrocytes”
- Dense network of collagen & elastic fibers embedded
- No blood vessels or nerves = very little repair
Areolar Tissue
* What are the characteritics?
* Possess all what?
* Why is it packing material?
- Loosely organized fibers, abundant blood vessels
- Possess all three fiber types and all six cell types
- “Packing Material”- underlies epithelia, in serous membranes, between muscles, passageways for nerves and blood vessels
Adipose Tissue
* What are the characterisitcs?
* What is the purpose
* What produces heat?
Empty-looking cells with thin margins; nucleus pressed against cell membrane
Energy storage, insulation, cushioning
* Subcutaneous fat and organ packing
* Brown fat of juveniles produces heat
Dense Irregular Connective Tissue
* What are the characteristics?
* Withstands what?
* Locations?
- Densely packed, randomly arranged, collagen fibers and few visible cells
- Withstands unpredictable stresses
- Locations: deeper layer of skin; capsules around organs
What are the chemical, physical/mechanical and biologic barriers?
Chemical barriers
* Skin secretions fight bacteria
* Melanin protects against UV rays
Physical/mechanical barriers
* Keratin and glycolipids block most water and water- soluble substances
* Limited penetration of skin by lipid-soluble substances
Biological barriers
* Dendritic cells and macrophages
Skin
- How does the skin regulate body temp?
- What are the cutaneous sensations?
- What are the metabolic fxns?
- What type of reservoir?
- Excretion of what?
Body temperature regulation
* Thermoreceptors
* Sweat for evaporative cooling
* Vasoconstriction/vasodilation
Cutaneous sensations
* Pain, Pressure, Temperature
Metabolic functions
* Synthesis of vitamin D; Skin carries out first step, Liver and kidneys complete process
Blood reservoir
* Up to 5% of body’s blood volume
Excretion
* Salt and nitrogenous wastes in sweat
What are the 3 major regions of the skin?
- Epidermis — superficial region
- Dermis — middle region
- Hypodermis — deepest region
What are the layers of thin and thick skin?
What are the cells of epidermis and their fxn?
Langerhans (aka Dendritic cells) – immune function
Merkel cell (aka tactile cell) – detecting touch
Melanocytes – produces melanin
Keratinocytes – produces keratin
What is the stratum basale, spinosum, granulosum, lucidum and cornum layers?
What are stem cells and where are they located?
Give rise to ketatinocytes and found in basale
Keratinocytes
* What do they synthesize?
* Produced by what? Mitosis requires what?
* New keratinocytes push what?
- Great majority of epidermal cell. Synthesize keratin.
- Produced by mitosis of stem cells in stratum basale or mitosis of keratinocytes in deepest part of stratum spinosum. Mitosis requires abundant oxygen and nutrients, so once cells migrate away from blood vessels of the dermis, mitosis cannot occur
- New keratinocytes push older ones toward the surface. Over time, keratinocytes flatten, produce more keratin and membrane-coating vesicles. In 30 to 40 days a keratinocyte makes its way to the skin surface and flakes off (exfoliates) as dander
Melanocytes
* Synthesize what?
* Occur only in what layer?
Melanocytes
* Synthesize pigment melanin that shields DNA from ultraviolet radiation
* Occur only in stratum basale but have branched processes that spread among keratinocytes and distribute melanin
Tactile cells:
* What are they?
* What layer?
Touch receptor cells associated with dermal nerve fibers
In basal layer of epidermis
What are dendritic cells?
Several layers of keratinocytes joined together by desmosomes and tight junctions
Dermis
Connective tissue layer beneath epidermis
* Composed mainly of what?
* Well supplied with what?
- Composed mainly of collagen
- Well supplied with blood vessels, sweat glands, sebaceous glands, and nerve endings; houses hair follicles and nail roots
What is the papilary and reticular layer of the dermis (characteristics and purpose)
Hypodermis
* _ tissue
* Has more what?
* What is the purpose?
* Common site of what?
- Subcutaneous tissue
- Has more areolar and adipose than dermis has
- Pads body and binds skin to underlying tissues
- Common site of drug injection since it has many blood vessels
label the degree of burn
Damaged tissues can be repaired in two ways?
Stages in the Healing of a Skin Wound
* What is the first step?
Stages in the Healing of a Skin Wound
* What is the second step?
Stages in the Healing of a Skin Wound
* what is the 3rd step?
Stages in the Healing of a Skin Wound
* What is the 4th step?
Hair is divisible into three zones along its length?
- Bulb: swelling at base where hair originates in dermis or hypodermis. Only living hair cells are in bulb
- Root: the remainder of the hair in the follicle
- Shaft: the portion above the skin surface
What is:
* Dermal papilla:
* Hair matrix :
* Follicle:
- Dermal papilla: bud of vascular connective tissue encased by bulb. Only source of nutrition for hair
- Hair matrix : region of mitotically active cells above papilla. Hair’s growth center
- Follicle: diagonal tube that extends into dermis and possibly hypodermis
What are the different stages in the hair cycle?
Anatomy of a Fingernail
* Derivatives of what?
* Composed of what?
* What is the fxn?Clear, hard derivatives of stratum corneum
Composed of thin, dead cells packed with hard keratin
Protective
- Clear, hard derivatives of stratum corneum
- Composed of thin, dead cells packed with hard keratin
- Protective
Apocrine sweat glands
* Where are they located?
* Responds to what? Believe to secreate what?
* produces what?
* Ceruminous glands are waht?
Merocrine (eccrine) sweat glands
* Most what? Dense where?
* What is the fxn?
Suderiferous (sweat) Glands: Myoepithelial cells
* Contract in response to what? Found where?
- Contract in response to stimulation by sympathetic nervous system and squeeze perspiration up the duct
- Found in both apocrine and merocrine glands
Sweat:
* Begins as what? Produced by what?
* What is the ph? why?
* What in the sweat?
* Does not produce what?
* What is diaphoresis?
Sebaceous (Oil) Glands
* What are the functions of the sebaceous glands?
- produce sebum
- waterproofs and softens skin and hair
