VI Integuemtary System Homeostatic Imbalances Integumentary Homeostasiswae PDF

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VI - Integumentary System Homeostasic Imbalances

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At the end of this topic, students will be able to: Describe the cells involved in repairing damaged skin. Compare homeostasis of cell number and mitotic rate in the epidermis with pathological conditions, including psoriasis and skin cancer. Describe the effect of scarring on regeneration of the skin Predict issues related to loss of skin in burn victims for first-, second- and third-degree burns. Describe different sensory receptors located in the integumentary system. Explain changes in the integumentary system that occur because of puberty and advanced age. Describe how a medical professional can use changes in the appearance of the skin to predict certain medical conditions.

Presentation of Contents Now you’ve learned about the amazing regenerative capacity of skin: Basal cells divide and differentiate to form keratinocytes, which move superficially to the surface and change their structure along the way. There are some cases where this regenerative property can cause problems, and some traumas where regeneration is put to the test. Example: Psoriasis is an autoimmune disorder where too many skin cells are produced. Skin rapidly accumulates and looks silvery-white in appearance. Plaques from plaque psoriasis frequently occur on the skin of the elbows and knees, but can affect any area, including the scalp, palms of hands and soles of feet, and genitals. The disorder is a chronic recurring condition that varies in severity from minor localized patches to complete body coverage. Cause is unknown Wound Repair and Scarring The first step to repairing damaged skin is the formation of a blood clot that scabs over with time. Many different types of cells are involved in wound repair, especially if the surface area that needs repair is extensive. Before the basal stem cells of stratum basale can re-create the epidermis, fibroblasts and mesenchymal cells mobilize and divide rapidly to repair the damaged tissue,

forming a loose, highly vascular tissue called granulation tissue. This increased vascular network helps deliver the oxygen and nutrients necessary for further repair. Immune cells, like macrophages, roam the area and engulf any foreign matter, reducing the chance of infection while also clearing away any tissue debris. Scars occur when there is repair of skin damage, but the healing process prevents regeneration of the original skin structure. Almost every cut or wound, with the exception of ones that only scratch the surface (epidermal wounds), leads to some degree of scar formation. As the tissue tries to repair itself to the original state, fibroblasts often generate a greater density of collagen fibers than were in the original tissue, which is what results in scar formation. Scarring of skin after wound healing is a natural process and does not need to be treated further. Application of oil and lotions may reduce the formation of scar tissue by keeping the skin soft and pliable as it heals, allowing the separate edges to be pulled together. However, modern cosmetic procedures like dermabrasion, laser treatments, and filler injections have been invented as remedies for severe scarring. All of these procedures try to reorganize the structure of the epidermis and underlying collagen in the connective tissue to make it look more natural.

1. New cells to replace the cells that were damaged will originate from: a. stratum basale, b. plaques c. macrophages d. stratum corneum 2. What is the difference between a keloid scar and an atrophic scar? a. There is no difference; they are the same type of scar b. A keloid scar is sunken and an atrophic scar is raised c. A keloid scar is raised and an atrophic scar is sunken d. A keloid scar is sunken and an atrophic scar is hypertrophic.

Burns Burns are wounds that result when the skin is exposed to intense heat, radiation, electrical current, or caustic chemicals. Burns cause skin cells to die, disrupting the epithelial barrier that normally prevents fluid loss. Depending on the severity of the burn, dehydration, electrolyte imbalance, and renal and circulatory failure may follow. Burn patients are treated with intravenous fluids to offset

the dehydration, as well as intravenous nutrients that enable the body to repair tissues and replenish lost proteins. Another serious threat to a burn patient is the high possibility of infection. Burned skin is extremely susceptible to bacteria and other pathogens, as the loss of body covering provides a direct pathway for the entry of microorganisms. Burns are To widen your understanding about burns on how they are classified by the degree of their severity and medical management, Read Seeley’s or Marieb 12th ed.

Changes in the Integumentary System Puberty During puberty, the changes in the endocrine system produce hormones that regulate aspects of the integumentary system. Sebaceous glands, apocrine sweat glands and hair growth become active or more active. Advanced Aging All organ systems in the body, including the integumentary system, undergo subtle changes over time that add up as a person ages. Reductions in metabolic activity and cell division, lowered blood

circulation, and decreased hormonal levels are some of the basic changes that occur in the human body as it ages. Many anti-aging products line the shelves of stores today. These products (mainly composed of tretinoin, or Retin-A) try to introduce more structure into the skin, first by rehydrating the skin with moisturizers, and then by triggering mitotic activity of the underlying cells to encourage tissue formation and regeneration. Some products contain epidermal growth factor, which induces collagen synthesis, the end-product of wound healing, to give the skin a healthier look. Read Marieb 12th ed. and list down the effects of aging in the skin.

Which of the following is a result of the rate of cell division slowing with old age? a. weakening of the muscles b. wrinkling of the skin c. paler appearance d. slower wound repair Thermoregulation and Thermal Homeostasis The integumentary system regulates body temperature through several different means. Recall that sweat glands — accessory structures to the skin — excrete water, salt, and other substances to cool the body when it becomes warm. This is termed "sensible perspiration." Even if the body does not appear to be noticeably sweating, approximately 500 mL of sweat are secreted a day. If the body becomes excessively warm due to high temperatures, vigorous activity, or a combination of the two, the blood vessels in the integumentary system dilate and sweat glands produce large amounts of sweat — up to three gallons a day. As the sweat evaporates from the skin surface, the body is cooled; in a way, the skin surface acts like the radiator of a car. The dilated blood vessels in the dermis that account for the redness that many people experience when exercising on a hot day also help in the dissipation of body heat by increasing the superficial blood flow. Check it out! Which of the following is involved in conserving heat? a. dilated blood vessels b. epithelial tissue c. sweating d. erect hair

The Sense of Touch The fact that you can feel an ant crawling on your skin, causing you to flick it off before it bites, is due to the fact that the sensory receptors in the skin (especially the hair root plexus associated with the hair in the follicles) can sense changes in the environment. This occurs via sensory receptors that convert physical or chemical stimuli into electrical signals that are sent to the central nervous system (CNS; brain and spinal cord). The CNS then processes this sensory input and generates a voluntary response to the ant. The skin acts as a sense organ because the dermis and hypodermis contain sensory receptors that extend into the epidermis. These receptors, such as Merkel discs, are more concentrated at the fingertips and lips, which are most sensitive to touch. Examples of other sensory receptors present in the skin are tactile (Meissner's) corpuscles and lamellated (Pacinian) corpuscles that respond to pressure and vibration, respectively, and free nerve endings that are sensitive to temperature (hot or cold) and pain. Skin Conditions and General Health There are a variety of conditions that can change the appearance of the skin. In vitiligo, the melanocytes in certain areas lose the ability to produce melanin, possibly due to an autoimmune reaction, leading to loss of pigmentation in patches. Liver disease or liver cancer can cause an accumulation of bile and the yellow pigment bilirubin, leading to the skin appearing yellow or jaundiced ("jaune" is French for "yellow"). The oxygen content of blood in the dermal vascular system is reflected in skin hue. Healthy individuals who have adequate supplies of the red-colored oxygen-bound hemoglobin usually have a pink hue to their cheeks and lips. Indeed, hemoglobin and the vasculature of the skin also contributes to skin color in people with fairer skin. A sudden drop in oxygenation of the skin can initially cause the skin to turn ashen (or white), pale or pallor. If there is a prolonged reduction in oxygen levels, it makes the skin appear blue (cyanosis), which happens when a person has a limited oxygen supply to the body.

Read and expand your knowledge on how emotions can influence the skin color. Read Marieb 12th Ed.

1. A person who recently shaved, may not feel an ant crawling on his or her skin because: a. The tactile corpuscles were damaged by the razor.

b. The Merkel discs are not being stimulated c. The hair root plexus are not being stimulated d. The lamellated corpuscles were damaged by the razor 2. When a person is extremely cold, his or her lips may turn which color? a. blue, because of a lack of oxygen b. bronze, because of too much copper c. red, because of a lack of oxygen d. yellow, because of a buildup of bile Summary Here is what you’ve learned from this lesson • • • • •

Burns result in loss of body fluids and invasions of bacteria. The extent of burn can be assessed the rule of nines. Burns represent a major threat to the body. Process of wound healing ang skin regeneration and possible scarring. The skin is thick, resilient and well hydrated in our youth but loses elasticity and thins as we age. We can use changes in the appearance of the skin to predict certain medical conditions. Skin conditions can change the appearance of the skin.

Reflection: 1. What do you still want to learn about? 2. How might you use what you learned in the future in your life or profession? 3. What did you learn that was unexpected?

References: Essentials of Human Anatomy & Physiology: Elaine Marieb & Suzanne Keller 12th edition, Pearson, 2018

Anatomy & Physiology and Disease: Deborah Roiger & Nia Bullock : 2 nd Edition; Mcgraw, 2019 Fundamentals of Anatomy & Physiology; Dr. Donald Rizzo; 4 th edition; Cengage Learning 2016...