Ch 6-10: Anatomy and Physiology
Study Guide
The ______ and its ______ organs make up the integumentary system. - skin, accessory
What are the accessory organs of skin? - hair, nails, glands, and sensory receptors
What is the function of skin? - The skin acts as a barrier between internal environment and the
external environment.
The skin consists of an outer ______ and an underlying ______, connected to underlying tissue by
the ______ layer. - epidermis, dermis, subcutaneous
What is another name for the subcutaneous layer of the skin? - hypodermis
The subcutaneous layer is composed mainly of ______ and ______tissue. - loose areolar connective,
adipose
What fibers do the subcutaneous layer consist of? - collagen and elastic fibers
What are the functions of the subcutaneous layer? - The subcutaneous layer binds skin to underlying
tissues but is not part of the skin. The adipose layer of the subcutaneous layer insulates, helping to
conserve body heat. The subcutaneous layer also contains major blood vessels that supply the skin
and underlying adipose tissue.
The epidermis is made up of stratified ______epithelium and lacks ______. - squamous, blood
vessels
What are the epidermal layers from innermost to outermost? - stratum basale, stratum spinosum,
stratum granulosum, and stratum corneum
Describe the stratum basale. - also known as stratum germinativum
deepest layer; consists of dividing cells; well-nourished by dermal blood vessels; as the cells of this
layer divide and grow, the older epidermal cells (keratinocytes) are pushed away from the dermis
,toward the skin surface. The farther the cells move away from the dermis toward the skin surface,
the poorer their nutrient supply becomes, and in time, they die (keratinization).
Describe the stratum spinosum. - also known as prickle cell layer
8-10 cell layers; contains irregular, polyhedral cells with cytoplasmic processes (spines) that extend
outward and contact neighboring cells by desmosomes; this layer contains dendritic cells; consists of
keratinocytes held together by sticky proteins called desmosomes; help makes your skin flexible and
strong
Describe the stratum granulosum. - also known as granular layer
thin layer of cells; keratinocytes are migrating from stratum spinosum; accumulate dense basophilic
keratohyalin granules which help to form a waterproof barrier that functions to prevent fluid loss
from the body; keratohyalin granules in this layer aids in the binding of keratin filaments together
and form a lipid barrier due to these cells having lamellar bodies filled with lipids
Describe the stratum corneum. - 25 - 30 layers of flattened, dead
keratinocytes; tough, tightly packed dead cells. The cells are extremely thin and flat and no longer
contain nucleus or organelles; they only contain keratin. The cells overlap like scales on a snake.
Dead cells in this layer eventually sheds.
When does the epidermis consist of 5 layers instead of the normal 4? - there are five layers in thick
skin, but in most areas, the epidermis consist of four layers.
What is the fifth layer of the epidermis? - stratum lucidum
In what areas does the skin contain the stratum lucidum? - in the thickened and hairless (glabrous)
skin of the palms and soles
Which layer of the epidermis is the living, reproducing layer? - stratum basale
What are the proteins of the epidermis? - keratin and melanin
,What is the function of keratin? - Keratin helps with water retardation and makes skin impervious
and tough as keratin is a tough, fibrous, waterproof protein.
What is the function of melanin? - A pigment that provides skin color; more melanin, the darker the
skin; absorbs ultraviolet radiation in sunlight.
What type of cell produces melanin? - melanocytes (specialized cells in the epidermis)
What factors contribute to the color of the skin? - As all people have about the same number of
melanocytes, skin color is determined genetically and involves the amount of melanin the
melanocytes produce. Factors that can contribute to the color of the skin are a combination of
genetic, environmental, and physiological factors. In addition to the amounts of melanin produced,
the size and distribution of melanin granules also affect genetic differences in skin color. An increase
in melanin production can occur due to exposure to sunlight, UV light from sun lamps, and X-rays.
Circulation within dermal blood vessels also affects skin color as well-oxygenated blood has a pinkish
color (because of hemoglobin) and poorly oxygenated blood looks blue (because of the deep red
tone of the hemoglobin). A skin can appear yellow due to eating too many orange foods with
carotene or from jaundice due to liver disease.
The dermis consists of ______ with collagen and elastic fibers within a gel-like ground substance. -
areolar and dense connective tissue
What other organs and fibers are in the dermis? (other than collagen and elastic fibers) - nerve
fibers, sensory fibers, hair follicles, sebaceous glands, and sweat glands
The boundary between the epidermis and dermis is uneven due to epidermal ______ and dermal
______. - ridges projecting inward, papillae (conical projections of dermis) extending into the spaces
between the ridges
A nail consists of a ______ that overlies a layer of skin called the ______. - nail plate, nail bed
Why are nails harder than the epidermal stratum corneum? - Nails are harder than the epidermal
stratum corneum because the keratin of nails is harder than that produced by the epidermal stratum
corneum. Specialized epithelial cells continuous with epithelium of the skin produce the nail bed.
The epithelial cells at the lunula keep on dividing and having newly formed cells that become
keratinized. This gives rise to tiny, keratinized scales that become part of the nail plate, pushing it
forward over the nail bed.
, Where is hair found? - all skin surfaces other than the palms, soles, lips, nipples, and parts of the
external reproductive organs
Define the term hair follicle - Each hair develops from a group of stem cells at the base of a tubelike
depression
What is the function of arrector pili muscles? - to make a short hair within the follicle stand on end
when the muscle contracts. For example, if a person is emotionally upset or very cold, nervous
stimulation may cause the arrector pili muscles to contract, producing gooseflesh, or goose bumps.
What determines hair color? - Genes determines hair color by directing the type and amount of
pigment that epidermal melanocytes produce.
What types of glands are sebaceous glands? - holocrine glands
What structure are sebaceous glands associated with? - hair follicles
What is the secretion of sebaceous glands are called? - sebum
What does sebum do? - waterproofs and moisturizes the hair shafts and skin
What are the glands in sweat glands? - eccrine glands, apocrine glands, and ceruminous glands
What are sweat glands also known as? - sudoriferous glands
Eccrine glands respond to ______. - body temperature
Apocrine glands respond to ______. - fear, emotional upset, pain, or sexual arousal
Ceruminous glands are found in the ______ and secrete ______. - ear canal, wax
Proper ______ regulation is vital to maintaining metabolic reactions. - temperature