23 terms

Anatomy - Skin - Dermis, Hypodermis, Thickness and Color

Dermis, Hypodermis, Thickness and Color
- second layer of skin
- consists of dense connective tissue
Function of dermis
- nourish epidermis via vast network of blood capillaries and vessels
- form supporting framework composed of collagen (strength) and elastin (elasticity)
List the 7 structures of the dermis
- blood capillaries
- lymph vessels
- sensory nerve endings
- arrectores pilorum muscle
- sweat glands and ducts
- sebaceous glands
- hair follicles
List the 2 layers of the dermis
- papillary layer
- reticular layer
Papillary Layer
outer layer of the dermis, directly beneath the epidermis, consists of many papillae
Reticular Layer
deeper layer of the dermis, consists mainly of bands of strong, white, fibrous collagen fibers and some yellow elastic fibers
Dermal Papilla
- fingerlike projection of the papillary region of the dermis
- consists of fine fibril tissue and a few elastic fibers, some may contain tactile nerve endings
List functions of dermal papillae
- on palms and soles, papillae are arranged in parallel lines to form a person's fingerprints
- protect against continuous friction
- help prevent slippage (when holding an object or walking)
Functions of blood vessels of the dermis
- arterioles supply sweat glands, sebaceous glands, hair follicles and the dermis with oxygen and nutrients
- deoxygenated blood is carried away by venules
- temperature regulation
- clot building when skin is cut to prevent further escape of flood and bacteria entering the body
Function of lymph vessels in the dermis
- drain away waste particles that are too large for veins to carry
Hair Follicles
- formed by down-growth of epidermal cells into the dermis
- tube like pockets of epidermal cells that make hair cells and external keratin
- exists of bulb, root and shaft
Arrector Pili Muscle
Tiny smooth involuntary muscle, attached to hair follicle and contracts when cold or frightened and produces goosebumps.
sensory nerve endings in the dermis
sensitive to touch, pressure, pain, heat and cold, conveying nerve impulses to the CNS
Sweat glands
tubular structures that produce sweat
Sebaceous glands
microscopic glands that secrete sebum, an oily/waxy matter that lubricates and waterproofs the skin and hair
- deepest layer of the skin
- formed from loose connective tissue, separating upper layers of skin from underlying muscle tissue
- permits skin to move easily over muscle
- contains blood and lymph vessels, nerves and fat cells
Which factors affect skin thickness
- area of the body: skin is thinnest on eye-lids and thickest on the palms and soles
- age: skin becomes thinner as one ages
- environmental exposure: UV exposure makes skin thicker
- oil content: more oily skin is thicker than dryer skin
- medication: e.g. cortisone results in thinning of skin
Which factors affect skin color
- skin thickness
- blood vessels and flow
- melanocytes and melanin
- carotene
Name 5 pigments that affect skin color and give their color and location
Pigment Color Location
Haemoglobin purple part of red blood cells
Oxyhaemoglobin red part of red blood cells
Melanin brown stratum germinativum
Melanoid brown throughout epidermis
Carotene yellow/orange stratum corneum, adipose cells
Which nutrients are necessary for the production of collagen?
Collagen is a protein and amino acids are the building blocks for proteins. The production of collagen therefore requires various nutrients that enhance the production of the amino acids alanine, lysine, glycine, proline and hydroxyproline. Major protein sources in a healthy diet include lean meat, fish, dairy products, legumes, nuts and seeds. Other nutrients for collagen production include Vitamin C, iron, manganese and Vitamin D.
Langer's Lines
also called cleavage lines, bundles of fibers in reticular layer of dermis, if surgery is performed along these lines only a fine scar is usually left
Cells of the dermis
fibroplasts, mast cells and histiocytes
Fibers of the dermis
elastin and collagen