Integumentary System II Flashcards
Where is the Dermis located?
Between the Epidermis and subcutaneous layer
What are the 2 components of the Dermis?
- Outer Papillary layer
2. Deep Reticular layer
What is the Function of the Dermis?
Anchors epidermal accessory structures
What does the Dermal Papillary layer consist of?
Areolar tissue, smaller capillaries, lymphatics & sensory neurons
What layer becomes inflamed in Dermatitis (Eczema)?
Dermal Papillary layer
Which is the more thicker component of the Dermis?
Reticular layer
What does the Dermal Reticular layer consist of?
Dens irregular connective tissue of all cells, collagen & elastic fibers (mainly)
What do Collagen fibers do?
Limit flexibility to prevent damage to tissue (provide resilience)
What do Elastic fibers do?
Provide flexibility
How is skin turgor provided?
By water and fibers
What causes the Loss of skin turgor?
- Dehydration (reversible)
- Aging
- Hormones
- Radiation
What may excessive distortion of the skin from pregnancy or weight gain cause?
Stretch marks
What are Tension Lines?
Cleavage lines that are produced by parallel bundles of collagen and elastic fibers in the dermis. They resist force applied to the skin.
What happens to a cut made parallel to a tension line?
Remains shut and heals well
What happens to a cut at a right angle to the tension line?
Pulls open and scars
What are the Dermal blood supplies?
- Cutaneous Plexus (deep artery network in the reticular layer)
- Subpapillary Plexus (a branch of 1 going up the dermis)
- Contusion (Bruise) - occurs in papillary layer
What do the Nerve Fibers in the skin do?
- Control Blood Flow
- Adjust Gland Secretion rate
- Monitor Sensory receptors which respond to light tough and deep pressure from vibration
How is the Hypodermis connected to the Reticular layer?
By connective tissues
What is the function of the Hypodermis?
Stabilises position of the skin
What does the Hypodermis primarily consist of?
Adipose tissue, adipocytes that contain fat deposits, large arteries & veins (superficial layer)
What determines the distribution of subcutaneous fat deposits?
Sex hormones
What cosmetic procedure can reduce fatty deposits?
Liposuction
What are the 2 pigments that influence skin colour?
- Melanin
2. Carotene
What is Carotene?
Orange-yellow pigment
Where does Carotene accumulate?
In epidermal cells and fatty tissues of the dermis
What is the function of Carotene?
Can be converted to vitamin A that maintain epidermis and synthesize photo-receptor pigments in the eye
What may excess carotene cause?
Yellowing of the skin and eyes
What is Melanin?
Red-yellow or brown-black
pigment
Where is Melanin stored?
In intracellular vesicles
melanosomes
What is Melanin produced by?
Melanocytes
What is the function of Melanocytes?
Protects skin from ultraviolet (UV)
radiation
What does sun exposure cause?
Sun exposure causes more
melanin production to protect
from UV ray which causes
darkening of the skin (tanning)
What does too much sun exposure cause?
Sun-burn
How does Blood Flow & Oxygenation influence Skin colour?
Hemoglobin = bright red when bound to oxygen Hemoglobin = dark red when oxygen is released (blue-ish skin colour)
What illnesses influence skin colour?
- Jaundice (Buildup of bile produced by liver)
- Pituitary Tumour (excess MSH)
- Addison’s Disease (excess ACTH)
- Vitiligo (Loss of melanocyte)
How is Vit D (cholecalciferol) produced?
Epidermal cells produce vitamin D3
from UV rays (Sunlight activate steroid compound
known as 7-dehydrocholesterol)
What is the function of Vit ?
Liver and kidneys convert vitamin D3 into calcitriol that
aid absorption of calcium and phosphorous
What does insufficient Vit D cause?
Rickets
What are Exocrine Glands?
Glands that produce and secrete substances onto an
epithelial surface by way of a duct
What are the 2 exocrine glands in the skin?
- Sebaceous Glands (oil glands)
2. Sweat Glands
What are Sebaceous Glands?
A holocrine gland (production of secretion include dead cells)
that discharges lipid secretion (sebum) into hair follicles
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What is the function of Sebum?
Lubricate and protect hair shields and inhibit growth of bacteria
What types of sweat glands are there?
- Apocrine (only in hairy areas, secrete substance indirectly)
- Eccrine (more abundant, secrete substance directly)
