The Integumentary System (The Skin) Flashcards
how does the integumentary system contribute to homeostasis
by protecting the body and helping regulate body temperature
allows us to sense pleasurable, painful,
and other stimuli from our external environment
integumentary system includes
skin, hair, oil and sweat glands,
nails, and sensory receptors
integumentary system main function
- Regulate body temperature
- Store blood
- Protect the body from our external environment
- Detect cutaneous (skin) sensations
- Excrete and absorb substances
- Synthesize vitamin D
skin 2 main parts
epidermis
dermis
epidermis
superficial, thinner portion of the skin which is made up of epithelial tissue
It is avascular, meaning there is no blood located in this type of thin tissue
dermis
the much deeper, thicker connective tissues
which is vascular, meaning if you cut into the dermis there is bleeding
subcutaneous tissue
also known as the hypodermis
Deep into the dermis
consists of areolar and adipose tissues.
Fibers that extend from the dermis anchor the skin to the subcutaneous tissue, which in
turn attaches to underlying fascia, the connective tissue around muscles and bones
what does subcutaneous tissue do?
serves as storage for fat and contains large blood vessels that supply the skin
contains nerve endings known as lamellar corpuscles which are sensitive to the sensation of pressure
epidermis contains
made up of keratinized stratified squamous
epithelium cells
contains four basic types of cells, these are:
1. Keratinocytes
2. Melanocytes
3. Dendric cells
4. Tactile epithelial cells
Keratinocytes
are responsible for 85% of the skin structure
arranged in four or five layers and produce a protein called keratin
produce something called lamellar granules
keratin
a tough, fibrous protein that helps protect
the skin and underlying tissues from abrasions, heat, microbes, and chemicals
lamellar granules
release a water repellent like sealant that decreases water entry and loss and inhibits the entry of foreign materials through the skin
Melanocytes
create roughly 8% of the skin’s structure,
our pigment producing cells
They migrate from the ectoderm of a developing embryo and produce the pigment melanin
melanin
a yellow-red or brown-black pigment that
contributes to skin color and absorbs damaging ultraviolet (UV) light
how melanin works
Within the keratinocytes, melanin granules cluster to form a protective veil over the nucleus to shield the nuclear DNA from damage by UV light
melanocytes themselves are particularly sensitive to UV light damage.
Dendric
also known as Langerhans cells
come from red bone marrow and
migrate to the epidermis where they make up about 5% of the skin structure
are part of the immune system and are in charge of immune responses mounted
against microbes that seek to invade the skin
Tactile epithelial cells
also known as Merkel cells,
he least numerous of our skin cells, making up only about 2% of our skin structure.
located in the deepest layer of the epidermis, where they make contact with the flattened process of a sensory neuron.
detect touch sensations
thin skin
epidermis has 4 strata (layers)
stratum basale
stratum spinosum
stratum granulosu
thin stratum corneum
thick skin
epidermis has 5 strata (layers)
stratum basale
stratum spinosum
stratum granulosum
stratum lucidum
thick stratum corneum
dermis
second and deeper part of the skin.
composed of dense, irregular connective tissue containing collagen and elastic fibers.
tensile strength (ability for pulling and stretching).
ability to stretch and recoil easily.
much thicker than the epidermis, and this thickness varies from region to region in the body, reaching its greatest thickness on the palms and soles.
ANATOMY OF A HAIR
Each hair is composed of columns of dead, keratinized epidermal cells bonded together by extracellular proteins
receive their own blood supply and epidermal stem cells
hair follicle
made up of an external root sheath and an internal root sheath
Sebaceous glands
also known as oil glands, are connected to your hair follicles
secrete an oily substance called sebum which is a mixture of triglycerides, cholesterol, proteins, and inorganic salts
Sudoriferous glands
t produces sweat which is released into hair follicles or onto the skin surface through pores
Eccrine sweat glands
simple, coiled tubular glands that are much more common than apocrine sweat glands.
They are distributed throughout the skin of most regions of the body, especially on the skin of the forehead, palms, and soles of the feet
sweat produced by eccrine sweat glands consists primarily of water, with small amounts of ions, urea, uric acid, ammonia, amino acids, glycose, and lactic acid
help regulate body temperature through evaporation.
Apocrine sweat glands
coiled tubular glands, but have larger ducts and lumens than eccrine glands.
They are found mainly in the skin of the armpit, groin, areolae of the breasts, and bearded regions of the face in adult males
apocrine sweat appears milky or yellowish in color.
Apocrine sweat contains the same components as eccrine sweat plus lipids and proteins.
Sweat secreted from apocrine sweat glands is odorless.
apocrine sweat interacts with bacteria on the surface of the skin, the bacteria metabolize its components, causing apocrine sweat to have a musky odour that is often referred to as body odour
ceruminous gland
modified sweat gland located in the external ear and produces a waxy lubricating secretion
cerumen, or ear wax.
Cerumen impedes the entrance of foreign bodies and insects, and also waterproofs the ear canal and prevents the entry of fungi and some bacteria to the cell.
