Lab Chp. Four: The Integumentary System Flashcards
integumentary system
skin and its accessory organs
What are the functions of the skin?
- Thermoregulation (homeostatic regulation of body temperature)
- Cutaneous Sensations (pressure and temperature)
- Protection (Physical, chemical, and biological barrier)
- Excretion and absorption
- synthesis of vitamin D
keratinocytes
make keratin which forms a physical barrier
pigments
protection from harmful UV rays
lipids
insulation
calcitrol
active form of Vitamin D
why is the synthesis of vitamin d in the skin so important?
because it allows calcium to be metabolized
precursors to vitamin d are synthesized when the skin is exposed to ______
UV radiation
What are the two distinct layers of skin?
- Epidermis
2. Dermis
Epidermis
- Stratified squamous epithelium
- some principle cell types:
a) keratinocytes
b) melanocytes
keratinocyte
the predominant cell type in the epidermis, the outermost layer of the skin, constituting 90% of the cells found there.
melanocyte
are melanin-producing cells located in the bottom layer (the stratum basale) of the skin’s epidermis. produces pigment.
What are the layers of the epidermis, in order from top to bottom?
- stratum corneum
- stratum lucidum
- stratum granulosum
- stratum spinosum
- stratum basale
Stratum corneum
many layers of keratinized, dead epithelial cells; appear scaly and flattened; resists water loss, absorption, and abrasion
stratum lucidum
cells appear clea; nuclei, organelles, and plasma membranes no longer visible
stratum granulosum
three to five layers of flattened granular cells; contain shrunken fibers of keratin and shriveled nuclei
stratum spinosum
many layers of cells with centrally located, large, oval nuclei; develop fibers of keratin; cells becoming flattened in superficial portion
stratum basale
a single row of cuboidal or columnar cells; layer also includes melanocytes; frequent cell division; some cells become parts of more superficial layers
Apocrine sweat gland
becomes active at puberty
arrector pili muscle
causes hair to stand on end and goose bumps to appear
dermis
inner layer of skin
eccrine sweat gland
responds to elevated body temperature
Epidermis
general name of entire superficial layer of skin
hair follicle
tubelike part that contains the root of hair
keratin
hard protein of nails and hair
melanin
epidermal pigment
sebaceous gland
gland that secretes an oily substance
sebum
an oily secretion that helps to waterproof the body surface
stratum basale
cell division and the deepest layer of the epidermis
stratum corneum
outermost layer of the epidermis
What layer of the epidermis is not in most samples?
lucidum
What makes up the dermis?
mostly connective tissue with collagen and ELASTIC FIBERS
What are the two layers of the dermis?
- Papillary Regions
2. Reticular Regions
Papillary Region (of dermis)
- superficial portion has AREOLAR TISSUE with elastic fibers
- dermal papillae
Reticular Region (of dermis)
- deeper portion of dermis
- DENSE CONNECTIVE TISSUE
Functions of the epidermis:
acts as the body’s major barrier against the environment
Functions of the dermis:
Holds most of the glands and nerve endings
-giving mechanical protection to the body from bumps and knocks; the collagen has an important role in this function
-providing oxygen and nutrients, via blood in the tiny vessels that run in the ground substance, to the living part of the epidermis
removing waste products of metabolism from the epidermis, which are also carried away in the blood
-providing shape and form to the body, by holding all its structures together
contributing to skin color, particularly in people with little melanin in the epidermis.
-Organs in the dermis have special functions of their own
regulation of body temperature through control of blood flow and sweating
skin sensations of touch, pain, heat and cold.
At what point in development do the epidermal ridges (aka-fingerprints) form?
Form in the 3rd or 4th month of fetal development
What do the accessory structures of the skin do?
-They function to protect the body and sweat glands regulate body temperature
What accounts for the distribution and thickness of hair?
Genetics and hormones
Where is hair found?
Not found on soles, palms, lips, nipples, external genitals
Connects the dermis to the root sheath
arrector pili
What are the four types of glands?
- Sebaceous glands
- Eccrine Glands
- Apocrine sweat glands
- Ceruminous glands
Sebaceous Glands
Secretes sebum
Eccrine glands
- release water based solution with salts
- aid in cooling the surface of a person
Apocrine sweat glands
- produces protein and lipid rich secretions
- found in the axillary and groin regions
Ceruminous glands
- modified glands of the external ear
- secrete earwax/cerumen
Where is the arrestor pili muscle located?
near the hair follicles of all mammals
Which muscle tissue type is the arrector pili muscle?
smooth muscle
Frequent cell division occurs in the
stratum basale
What fibers are associated with the dermis?
Elastic Fibers
the hair follicle surrounds the ____
root
Structure of the hair:
- root
- shaft
Both the root and shaft of the hair are compose of _____
epithelial cells that have become keratnized
The hair follicle is composed of:
- internal and external root sheath
- connective tissue root sheath
What is at the base of each hair follicle?
bulb
What does the hair papilla contain?
in the bulb. contains areolar tissue, blood vessels, and nerves
bulbs contain the hair papilla and what else?
a germinal layer of hair cells
