Integumentary System Flashcards
What are the two principal parts of the Integumentary System?
Epidermis and Dermis
The superficial, thinner layer composed of epithelial tissue
Epidermis
The deeper, thicker layer composed of dense irregular connective tissue
Dermis
What are the specific functions of the skin?
Thermoregulation Protection from external environment Cutaneous sensation Excretion Synthesis of vitamin D Reservoir for blood Absorbs substances
Excretion: what does sweat eliminate?
some water, salts, CO2, ammonia, urea
What are some characteristics of thermoregulation?
Evaporation of sweat cools the skin
Increased blood flow to the skin promotes heat loss by radiation
Hair traps heat, thereby reducing heat loss in cold temperature
The epidermis is composed of?
Keratinized stratified squamous epithelium
What are the four major types of cells of the Epidermis?
Keratinocytes
Melanocytes
Langerhans Cells
Merkel Cells
What is keratin?
tough, fibrous protein that waterproofs the skin
What does keratin do?
helps protect the skin and underlying tissues from heat, microbes, and chemicals
Keratinocytes (a layer of the epidermis) are formed when?
New cells produced by mitosis become filled with keratin.
What produces the pigment melanin?
the organelle melanosome
What is melanin?
A brown-black pigment that contributes to skin color and absorbs damaging ultraviolet light
Projections from _________ extend between keratinocytes, and do what?
melanocytes
They transfer melanin granules to them
What do the melanin granules do?
Cluster over the nucleus on the side toward the skin surface, shielding nuclear DNA from UV light.
What synthesize melanin from the amino acid tyrosine in the presence of the enzyme tyrosinase?
Melanosomes of melanocytes
Melanosomes of melanocytes synthesize melanin from the amino acid _____ in the presence of the enzyme ______
Tyrosine
Tyrosinase
What participates in immune responses to microbes that invade the skin (immune cells)?
Langerhans Cells
Langerhans cells are a type of what kind of cell?
Dendritic
What resides in the deepest layer of the epidermis where they contact the flattened processes of tactile discs?
Merkel Cells
What are the tactile discs, a type of sensory cell, the merkel cells contact called?
Merkel discs
What functions in the sensation of touch?
Merkel cells and tactile discs
What are they layers of the epidermis?
Stratum Corneum Stratum Lucidum Stratum Granulosum Stratum Spinosum Stratum Basale
What is the deepest layer of the epidermis?
Stratum Basale
What is the Stratum Basale made up of?
Mostly keratinocytes, a few melanocytes and Merkel cells
Keratinocytes have what type of filaments? and they are called?
Intermediate filaments
Tonofilaments
What are tonofilaments composed of?
A protein that will later form keratin
What has 8-10 layers of keratinocytes and a few Langerhans cells?
Stratum Spinosum
Older cells in the stratum spinosum start to?
Flatten
True or False
Cells in the stratum spinosum are still alive and some divide
True
3-5 layers of flattened keratinocytes and is a transition between living cells and the more superficial dead cells
Stratum Granulosum
In the stratum granulosum, what release a waterproofing lipid solution?
Lamellar granules
What is stratum granulosum filled with?
Granules of keratin
These are only found on fingertips, palms of hands, soles of feet.
Stratum Lucidum
What has 3-layers of flattened dead keratinocytes filled with keratin?
Stratum Lucidum
What is the most superficial layers of the epidermis that has 25-30 layers of flattened, dead cells?
Stratum Corneum
What provides waterproofing in the stratum corneum?
Between cells, lipids for lamellar granules
This layer of cells in the epidermis, interior of cells contains mostly keratin. The cells are continuously sloughed off and replaced by cells from deeper strata.
Stratum Corneum
What is dense irregular connective tissue that contains collagen and elastic connective tissue?
Dermis
What are the contents of the dermis?
Blood vessels
Nerves
Glands; sebaceous (oil) and sudoriferous (sweat)
Hair follicles
Arrectores pilorum muscles (singular is arrector pili)
What are the two components of the dermis?
Papillary region
Reticular region
What is the superficial part of the dermis?
Papillary region
What greatly increase the surface area of the papillary region? Why?
Dermal papillae
Gives better adhesion to epidermis
More surface area for diffusion to and from epidermis
What receptors are present in the papillary region of the dermis?
Touch corpuscles (Meissner corpuscles) for touch/light touch
What are touch corpuscles?
Free nerve endings with no apparent structural specialization that give rise to sensation of warmth, coolness, pain, tickle, itch
What consists of dense, irregular connective tissue containing bundles of collagen and some elastic fibers?
Reticular region of the dermis
The space between the fibers of the dermis are occupied but what?
Adipose cells Hair follicles Nerves Sebaceous (oil) glands Sudoriferous (sweat) glands
The combination of collagen and elastic fibers in the reticular region of the dermis provides?
the skin with strength, extensibility, and elasticity
What is the hypodermis?
Subcutaneous layer
What is the subcutaneous layer composed of ?
Areolar and adipose tissues
What does the subcutaneous layer contain?
Fat
Fibers that attach the dermis to deeper tissues
Larger blood vessels
Sensory receptors: Pacinian corpuscles (lamellated corpuscles)
What do Pacinian corpuscles sense?
Pressure
What are the epidermal ridges commonly called?
Fingerprints
What develops during the third and fourth fetal months as the epidermis conforms to the contours of the underlying dermal papillae of the papillary region?
Epidermal ridges (Fingerprints)