A&P1 - LP#8/9 Flashcards
Structure of the skin Accessories of the skin Function of the skin Sensation Appearance (27 cards)
_________ is also known as the cutaneous membrane
Skin
__________ is the largest organ in the body in surface area and weight
Skin
The skin has TWO main parts:
- Epidermis (superficial)
- Thin: composed of epithelial tissue
- Dermis (deep)
- Thicker connective tissue
______________ is a third unofficial layer of the skin that is deep to the dermis (but is not a part of the skin)
Subcutaneous Layer
This structure of the skin is composed of keratinized stratified squamous epithelium.
Keratinized - tough fibrous intercellular protein that helps protect skin and underlying tissues from heat, microbes and chemicals.
Epidermis
There are FIVE distinct cellular layers of the epidermis:
- Stratum Basale - Deepest Layer
- Stratum Spinosum - Superficial to the Stratum Basale
- Stratum Granulosum - Mid-layer, between Stratum Spinosum and Stratum Lucidum (undergoing apoptosis)
- Stratum Lucidum - Present only in thick skin such as fingertips, palms, etc.
- Stratum Corneum - 25-30 layers of flattened dead cells
This structure of the skin is composed of strong connective tissues with collagen and elastic fibres - network of fibres - great tensile strength (resists pulling and stretching forces).
Blood vessels, nerves, glands and hair follicles are embedded in this layer.
This layer is essential to the survival of the epidermis - form many important structural and functional relations between layers
Dermis
There are TWO main groups of the Dermis
- Papillary Region
2. Reticular Region
This accessory structure of the skin is present on most surfaces of the skin except the palms, palmar surfaces of the fingers, the soles, and the plantar surfaces of the feet.
In adults, it is predominant in the scalp and head, axilla and external genitalia.
Provides limited protection; guards scalp from injury and sun light; protects eyes, nose and ears from foreign matter; sensing light touch.
Hair
The proper anatomical term for hair is __________
Pili
This accessory structure of the skin consists plates of tightly packed, hard, dead keratinized epidermal cells that form a clear solid covering of the digits.
Nail
This accessory structure of the skin contains epithelial cells that secrete substances such as oil, sweat or ear wax.
Skin Glands
What are the THREE exocrine glands associated with the skin?
- Sebaceous (oil) Glands
- Sudoriferous (Sweat) Glands
- Ceruminous (ear wax) Glands
This glands are simple, branched acinar glands that are attached to hair follicles. The secreting portion lies in the dermis and usually opens into the neck of the hair follicle. They secret an oily substance called sebum
Sebaceous Glands
What are FOUR functions of Sebaceous Glands?
- Coats the surface of hair and keeps them from drying and becoming brittle.
- Prevents excessive evaporation of water from skin
- Keeps skin soft and pliable
- Inhibits growth of some bacteria.
The cells of these glands release sweat or perspiration, into the follicles or onto skin surfaces through pores. These glands are divided into two groups: Eccrine and Apocrine.
Sudoriferous Glands
This type of sudoriferous (sweat) gland is distributed througout the skin of most regions of the body. Not present in lips, nail beds, glans penis, glans clitoris, and eardrums. It functions to help regulate temperature through evaporation - as sweat evaporates, large quantities of heat leave the body surface.
Eccrine Sweat Glands
This type of sudoriferous (sweat) gland is mainly found in the skin of the axilla (armpit), groin, areola of breasts bearded regions on adult male faces. Secretions done by exocytosis. Secretory portion located mostly in the subcutaneous layer; ducts open into hair follicles. Consists of the same components as eccrine but with addition of lipids and proteins. Oderless, however smells when in contact with bacteria. Function: Emotional sweating, sexual activity, no role in thermoregulation.
Apocrine Sweat Glands.
This type of sudoiferous (sweat) gland is a modified sweat gland in the external ear and produces a waxy lubericating secretion. It’s secretory portion - like in the subcutaneous layer - is deep to subaceous glands. Excretory ducts open directly on the surface of external auditory canal or into ducts of sebaceous glands.
With ear hairs, it functions to provide a sticky barrier that impedes the entrance of foreign matter and insects. Waterproofs the canal and prevents bacteria and fungi to enter cell.
Ceruminous Glands
the homeostatic regulation of body temperature; skin contributes in TWO ways by liberating sweat at its surface and adjusting the flow of blood in the demis
Thermoregulation
The dermis houses an extensive network of blood vessels that carries _______________ of total blood flow in a resting adult - therefore, skin acts as a reservoir.
8-10%
There are several components in the skin that provide protection. __________ protects underlying tissue from microbes, abraision, heat and chemical
Keratin
There are several components in the skin that provide protection. __________ provide water resistance; guards againsts dehydration; retard re-entry of water during showers
Lipids
There are several components in the skin that provide protection. __________ keeps skin/hair from drying out
Sebum
