What are the functions of the Integumentary System?
Protection, Body Temperature Regulation, Cutaneous Sensations, Metabolic Functions, Blood Resevior, and Excretion.
What are the three levels of in the protection level of the Integumentary System?
Chemical, Physical, and Biological.
What does the Chemical Level do for the protection of the Integumentary System?
Low pH secretion (acid mantle) and defences retard bacterial activity.
What does the Physical Level do for the protection of the Integumentary System?
Keratin and glycolipids block most water, and water soluable substances. Limited penetration of the skin by lipid-soluable substances, plant oleoresins (poison ivy), organic solvents, salts or heavy metals, some drugs.
What does the Biological Barriers Level do for the protection of the Integumentary System?
Dendritic cells, macrophages, and DNA.
What is the Body Temperature Regulation for the Integumentary System?
~500 ml/day routine insensible perspiration (at normal body temperature), at elevated temperature, dilation of dermal vessels and increased sweat gland activity (sensible perspirations) cool the body.
What is the Cutaneous Sensations for the Integumentary System?
Temperature, touch, and pain.
What is the Metabolic Function of the Integumentary System?
Synthesis of Vitamin D, precurser and collagenase. Chemical conversion of carcinogens and some hormones.
What is the Blood Resevior for the Integumentary System?
Deepest epidermal layer that is firmly attached to the dermis, single row of stem cells, also called stratum germinativum; cells that undergo rapid division. Journey from basal layer to surface is 25 - 45 days.
What is Stratum Spinosum?
The prickly layer, cells contain a weblike system of intermediate prekeratin filaments attached to desosomes. Abundent melanin granules and dendritic cells.
What is Stratum Granulosum?
The Granular layer, thin. Three to five layers in which cells flatten. Keratohyaline and lamellated granuoles accumulate.
What is Stratum Lucidum?
Clear layer. In thick skin, is thin transparent band superficial to the stratum granulosum. A few rows of flat, dead keratinocytes.
What is Stratum Corneum?
Horny layer. Most superficial layer. 20 - 30 rows of dead keratinized membranous sacs. Three quarters of the epidermal thickness.
What are the functions of Stratum Corneum?
Protects from abrasion and penetration, is waterproof, barrier against biological, chemical, and physical assaults.
What are the layers of the Dermis?
The papilary and the reticular.
What is the Papillary layer of the Dermis?
Areolar connective tissue with collagen and elastic fibers and blood vessels. Contains papillary loops, meisenners corpuscles, and free nerve endings.
What is the Reticular layer of the Dermis?
~80% of the thickness of the dermis, collagen fibers provide strength and and resilliency, elastic fibers provides stretch-recoil properties.
What are the types of glands found in the Integumentary System?
Eccrine, Apocrine, Sebaceous.
What is an Eccrine Gland?
Merocrine, abundent on palms, soles, and forehead. Sweat 99% water, NaCl, Vitamin C, Antibodies, Dermcidin, and Metabolic Waste. Ducts connect to pores, function in thermoregulation.
What is a Apocrine Gland?
Confined to axillary, and anogenital areas. Ducts connect to hair follicles, functional from puberty onward, secret Sebum.
What are the specialized Apocrine Glands?
Ceruminous Glands in the external ear canal that secrete cerumen, and mammary glands.
What are Sebaceous Glands?
Widely distributed, most develop from hair follicle, become active at puberty, secret sebum.
What does Sebum do?
Oily holocrine secretion, bacterialcidal, softens hair and skin.
What are the pigments that attribute to the color of the skin?
Melanin, Carotene, and Hemoglobin.
What does Melanin do?
Yellow to redish-brown to black. Produced in melanocytes, migrates to keratinocytes where it forms pigment sheilds for nuclei. Freckles and pigmented moles.
What are freckles and moles?
Local accumulations of melanin.
What does Carotene do?
Yellow to orange color, most obvious in the palms of the soles.
What does Hemoglobin do?
Responsible for the pinkish hue of the skin.
What is Alopecia?
Hair thinning in both sexes after age 40.
What is Frank Baldness?
Genetically determined and sex influenced condition, male pattern baldness is caused by follicular responses to DHT.
What is a Pacinian Corpuscle?
They are nerve endings in the skin, responsible for sensitivity to deep pressure touch and high frequency vibration.
What is a Meissners Corpuscle?
They are a type of nerve endings in the skin that are responsible for sensitivity to light touch. In particular, they have highest sensitivity (lowest threshold) when sensing vibrations lower than 50 Hertz. They are rapidly adaptive receptors.