List AND describe some of the basic characteristics of the skin PDF

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1. List AND describe some of the basic characteristics of the skin a. Largest organ, covers the entire body 2. List AND describe some of the functions of the skin a. Protects skin, aids in body temperature regulation, retards water loss, houses sensory receptors, synthesizes various chemicals, secretes small quantities of waste substances. 3. Define desiccation. a. To remove the moisture from a thing that normally contains moisture 4. What type of epithelium is the skin composed of? a. Stratified squamous 5. List the 5 layers of the epidermis from deep to superficial. Now add the defining characteristics of each of these layers. In other words, what are the important functions of each layer? a. Stratum Basale i. Attached to the underlying dermis, row of renewing keratinocytes, 1025% melanocytes, small portion is merkel cells b. Stratum Spinosum i. Keratinocytes pushed up from Basale, filaments resist tension, spiny appearance, contain Langerhans cells. c. Stratum Granulosum i. 3-5 layers thick, keratinocytes flatten out and organelles disintegrate, membrane thickens, lipids coat outer surface, slowly die ii. 2 types of granules, keratohyaline (form upper layers) lamellated (waterproof glycolipids) d. Stratum Lucidum i. Only in thick skin, few layers thick, dead cells e. Stratum Corneum i. 20-30 cell layers, protective, durable overcoat, waterproof, tough. 6. Which layer of the epidermis is found only in the palms of the hands and soles of the feet? a. Stratum Lucidum 7. Which “specialized” cell types are found in the epidermis of the skin? What are the functions of each of these cells? a. Basal Cells, stem cells, continually divide and push up old cells b. Merkel cells – trigger nervous system, light touch sensation. 8. Explain the process of keratinization. a. As new cellsof the epidermis are produced and pushed upwards from the basement membrane cells undergo hardening process called keratinization. 9. What are the two major layers of the dermis? Compare and contrast the structures AND functions of these two layers. Make sure to address the receptors involved with cutaneous sensation. a. The dermis is composed largely of irregular dense connective tissue that includes tough collagenous fibers and elastic fibers in a gel-like substance. It has fingerlike projections called papillae that help form the fingerprints. The dermis also includes muscle tissue. It is usually smooth muscle, but striated muscle is also present in certain portions such as the face to help with voluntary facial movements. The dermis contains both sensory and

motor nerves. It also contains blood vessels, hair follicles, sebaceous glands, and sweat glands.

10. Describe how a blister forms. a. Separation of the epidermal and dermal layers by a fluid filled pocket. 11. What are lines of cleavage and what is their clinical significance? a. Arranged in parallel bundles, resist force in a specific direction 12. Describe the anatomy of the hypodermis. a. Adipose 13. List AND describe the functions of the hypodermis. a. Energy reservoir, thermal insulation. Few capillaries no vital organs. 14. Is the hypodermis considered a layer of the skin? Explain! a. No, more adipose than dermis 15. Why are shots often given into the hypodermis? a. Will not hit any key organs 16. Describe the typical subcutaneous fat distribution of males and females. a. The subcutaneous layer contains adipose tissue that acts as an insulator, conserving internal body heat and preventing the entrance of heat from the outside. This layer also contains the major blood vessels that supply nutrients and oxygen to the skin. 17. Label all of the major structures/regions on a diagram of the skin. a.

18. What are the major pigments found in the skin? Expand on the characteristics of each of these. a. Melanin – a brown/black or red/yellow polymer produced by melanosomes in melanocyte cells b. Haemoglobin in red blood cells in the superficial vasculature

c. Dietary carotenoids (e.g. carrots) – to a much lesser degree, and is often seen as a yellow colour on the palms d. Eumelanin is responsible for producing brown or black colour e. Phaeomelanin is responsible for yellow or red colour 19. Why do fair skinned individuals often have a reddish hue? a. Pheomelanin 20. Define cyanosis. What causes it? a. Blue-ish skin tine due to hemoglobin that is not saturated with oxygen. 21. List the regions where hair is not found. a. Palms of hand, and sole of feet 22. List AND describe the functions of hair. a. Protects and insulates i. Guards openings against particles and insects ii. Is sensitive to very light touch 23. What is the function of the arrector pili muscle? Which type of muscle tissue is this? a. Makes hair stand on end and is made up of smooth muscle connective tissue. 24. Compare and contrast the types of hair. a. Vellus Hair i. Body hair of females and children, pale and fine b. Terminal Hair i. Coarser, longer 25. What is alopecia? What are some common causes of this condition? a. Baldness, autoimmune system attacks follicles, old age, etc. 26. What is a sudoriferous gland? a. A sweat gland- a type of exocrine gland which are galnds that produce and secrete substances onto an eptithelial surface by way of duct. 27. Compare and contrast sensible and insensible perspiration. a. Insensible perspiration is oil and other secretions your not aware of but are doing, sensible is when you sweat to cool yourself down. 28. Compare and contrast the causes and clinical signs of dehydration and (over)hydration of the skin. a. Causes of dehydration can be makeup, diet, incorrect product use, weather, etc. sympoms may include excess oil. b. There are many causes, symptoms is the skin softens and breaks down 29. Compare and contrast the structure AND function of an eccrine and apocrine sweat gland. Make sure you know what modes of secretion are associated with each gland! a. Certain sweat glands, known as apocrine glands, respond to emotional stress and become active when a person is emotionally upset, frightened, or experiencing pain. They are most numerous in the armpits and groin. These are usually connected to hair follicles. The development of these glands is stimulated by sex hormones so they become mature at puberty. Eccrine glands are not associated with hair follicles, and function throughout life in response to elevated body temperature associated with environmental heat and physical exercise. These sweat glands are found primarily on the forehead, neck, and back where they produce profuse sweating.

30. What is the major function(s) of sebaceous glands? a. Sebaceous glands contain groups of specialized epithelial cells and are usually associated with hair follicles. They are holocrine glands that secrete an oily substance called sebum (a mixture of fatty materials and cellular debris) that serve to keep the hair and skin soft, pliable, and relatively waterproof. 31. Where do sebaceous glands typically empty their contents into? a. Ducts or the dermis 32. What mode of secretion is associated with sebaceous glands? a. The mode of secretion is refereed to as holocrine. 33. What are ceruminous glands? What mode of secretion is associated with these glands? What do they produce? What is the purpose of this product? a. specialized sudoriferous glands (sweat glands) located subcutaneously in the external auditory canal, in the outer 1/3. Ceruminous glandsare simple, coiled, tubular glands made up of an inner secretory layer of cells and an outer myoepithelial layer of cells. They are classed as apocrine glands. 34. What are mammary glands? What mode of secretion is associated with these glands? a. They are glands found in the breasts, the mode of secretion associated with these is apocrine. 35. Describe the steps involved in the repair of the integument. a. An initial response to maintain homoeostasis. i. circulation platelets within the blood begin to form a fibrin clot, which seals the wound site. Additionally, vasoconstriction initially occurs around the wound site as a means of isolating the wound site. However, this is soon followed by vasodilation so the required cells are able to be recruited to the wound site. Factors are released from damaged cells, and those around the wound site initiate the inflammatory response. b. An inflammatory response to prevent infection i. Immune cells, such as neutrophils and macrophages, are attracted by factors released from the wound site and begin to accumulate, travelling through the circulatory system. These cells are responsible for the removal of debris and killing of bacteria that easily colonize the wound site, and prepare the wound for the proliferative/remodelling phase. c. A proliferative phase to reconstitute the wound site. (if wound is shallow, 1st two not occur) i. Re-vascularisation: New blood vessels are formed around the wound site in order to supply the cells and nutrients required to remodel the wound. ii. Granulation: Fibroblasts attracted to the wound site quickly lay down a temporary extra cellular matrix, comprised of collagen and fibronectin, upon which the epidermis can be reconstituted. iii. Re-epithelialization: The exact mechanism of re-epithelialization is poorly understood. It is thought that surviving epithelial cells around the wound edge become more motile and stretch to cover the wound site. Once a continuous epidermis is formed they lose this motility and begin to divide.

iv. Contraction: Re-epithelization is thought to occur simultaneously with contraction, where myo-fibroblasts recruited around the wound site pull against each other to contract the size of the wound. d. A remodelling phase where tissue strength and function are restored. i. Following closure of the wound, remodeling can occur. The epidermis proliferates and returns to its normal character; fibroblasts and immune cells which were recruited to the site are degraded; and the temporary extra cellular matrix that was laid down is remodelled into a stronger, more permanent structure. 36. Summarize the major effects that aging has on the integument. a. Stem cell production declines with age, causing the epidermal cells to slow in their reproduction and, as a result, become larger and more irregular. This causes thinner, more translucent skin, meaning more frequent skin injuries, tearing, and infections....