Unit 3 Textbook Reading Integumentary System Answers
Learning Objectives
By the cease of this department, yous volition be able to:
- Describe the different functions of the peel and the structures that enable them
- Explicate how the skin helps maintain body temperature
The skin and accessory structures perform a diversity of essential functions, such as protecting the body from invasion by microorganisms, chemicals, and other environmental factors; preventing dehydration; acting as a sensory organ; modulating trunk temperature and electrolyte rest; and synthesizing vitamin D. The underlying hypodermis has important roles in storing fats, forming a "cushion" over underlying structures, and providing insulation from cold temperatures.
Protection
The skin protects the rest of the body from the bones elements of nature such equally wind, water, and UV sunlight. It acts every bit a protective bulwark confronting water loss, due to the presence of layers of keratin and glycolipids in the stratum corneum. Information technology also is the first line of defense against abrasive action due to contact with dust, microbes, or harmful chemicals. Sweat excreted from sweat glands deters microbes from over-colonizing the pare surface by generating dermicidin, which has antibody properties.
Everyday Connection
Tattoos and Piercings
The give-and-take "armor" evokes several images. You might recollect of a Roman centurion or a medieval knight in a suit of armor. The peel, in its ain way, functions as a form of armor—trunk armor. It provides a barrier betwixt your vital, life-sustaining organs and the influence of outside elements that could potentially harm them.
For any form of armor, a alienation in the protective barrier poses a danger. The skin tin can exist breached when a child skins a knee or an adult has blood drawn—one is accidental and the other medically necessary. Even so, you as well alienation this barrier when yous cull to "accessorize" your skin with a tattoo or body piercing. Considering the needles involved in producing body art and piercings must penetrate the skin, there are dangers associated with the practice. These include allergic reactions; skin infections; blood-borne diseases, such as tetanus, hepatitis C, and hepatitis D; and the growth of scar tissue. Despite the take a chance, the do of piercing the skin for decorative purposes has go increasingly popular. Co-ordinate to the American Academy of Dermatology, 24 percent of people from ages 18 to l have a tattoo.
Interactive Link
Tattooing has a long history, dating back thousands of years ago. The dyes used in tattooing typically derive from metals. A person with tattoos should exist cautious when having a magnetic resonance imaging (MRI) scan because an MRI machine uses powerful magnets to create images of the soft tissues of the torso, which could react with the metals contained in the tattoo dyes. Watch this video to acquire more about tattooing.
Sensory Function
The fact that yous can experience an ant crawling on your skin, allowing you to flick it off earlier it bites, is because the skin, and especially the hairs projecting from hair follicles in the skin, tin can sense changes in the surroundings. The pilus root plexus surrounding the base of operations of the hair follicle senses a disturbance, and and then transmits the data to the central nervous system (encephalon and spinal cord), which can then respond past activating the skeletal muscles of your eyes to see the pismire and the skeletal muscles of the body to act confronting the ant.
The skin acts as a sense organ because the epidermis, dermis, and the hypodermis contain specialized sensory nervus structures that detect bear on, surface temperature, and pain. These receptors are more concentrated on the tips of the fingers, which are most sensitive to affect, particularly the Meissner corpuscle (tactile corpuscle) ([link]), which responds to lite impact, and the Pacinian corpuscle (lamellated corpuscle), which responds to vibration. Merkel cells, seen scattered in the stratum basale, are also bear on receptors. In add-on to these specialized receptors, there are sensory nerves continued to each hair follicle, hurting and temperature receptors scattered throughout the skin, and motor nerves innervate the arrector pili muscles and glands. This rich innervation helps us sense our surround and react accordingly.
Figure 5.15 Light Micrograph of a Meissner Corpuscle In this micrograph of a pare cross-section, y'all can see a Meissner corpuscle (arrow), a blazon of touch receptor located in a dermal papilla adjacent to the basement membrane and stratum basale of the overlying epidermis. LM × 100. (credit: "Wbensmith"/Wikimedia Commons)
Thermoregulation
The integumentary system helps regulate torso temperature through its tight association with the sympathetic nervous system, the division of the nervous organisation involved in our fight-or-flight responses. The sympathetic nervous system is continuously monitoring body temperature and initiating appropriate motor responses. Recall that sweat glands, accessory structures to the skin, secrete water, common salt, and other substances to cool the torso when it becomes warm. Fifty-fifty when the body does not announced to be noticeably sweating, approximately 500 mL of sweat (insensible perspiration) are secreted a day. If the body becomes excessively warm due to loftier temperatures, vigorous activity ([link]air conditioning), or a combination of the two, sweat glands will be stimulated past the sympathetic nervous system to produce large amounts of sweat, as much as 0.7 to 1.5 L per hour for an active person. When the sweat evaporates from the pare surface, the body is cooled as body heat is dissipated.
In improver to sweating, arterioles in the dermis dilate and then that excess heat carried by the claret can misemploy through the skin and into the surrounding environment ([link]b). This accounts for the skin redness that many people experience when exercising.
Figure 5.16 Thermoregulation During strenuous physical activities, such as skiing (a) or running (c), the dermal claret vessels amplify and sweat secretion increases (b). These mechanisms forestall the torso from overheating. In contrast, the dermal blood vessels constrict to minimize heat loss in response to depression temperatures (b). (credit a: "Trysil"/flickr; credit c: Ralph Daily)
When trunk temperatures drop, the arterioles constrict to minimize oestrus loss, particularly in the ends of the digits and tip of the nose. This reduced circulation tin result in the skin taking on a whitish hue. Although the temperature of the skin drops as a consequence, passive oestrus loss is prevented, and internal organs and structures remain warm. If the temperature of the skin drops too much (such as environmental temperatures below freezing), the conservation of torso cadre heat can result in the skin really freezing, a condition chosen frostbite.
Aging and the...
Integumentary System
All systems in the body accumulate subtle and some not-and then-subtle changes equally a person ages. Among these changes are reductions in prison cell sectionalization, metabolic activeness, blood circulation, hormonal levels, and muscle strength ([link]). In the skin, these changes are reflected in decreased mitosis in the stratum basale, leading to a thinner epidermis. The dermis, which is responsible for the elasticity and resilience of the skin, exhibits a reduced power to regenerate, which leads to slower wound healing. The hypodermis, with its fat stores, loses structure due to the reduction and redistribution of fat, which in turn contributes to the thinning and sagging of skin.
Figure 5.17 Aging Generally, skin, especially on the face and hands, starts to display the starting time noticeable signs of crumbling, as information technology loses its elasticity over time. (credit: Janet Ramsden)
The accompaniment structures also have lowered activity, generating thinner hair and nails, and reduced amounts of sebum and sweat. A reduced sweating power can crusade some elderly to exist intolerant to extreme rut. Other cells in the skin, such as melanocytes and dendritic cells, also become less agile, leading to a paler skin tone and lowered immunity. Wrinkling of the skin occurs due to breakup of its structure, which results from decreased collagen and elastin production in the dermis, weakening of muscles lying under the pare, and the inability of the skin to retain adequate moisture.
Many anti-aging products can be establish in stores today. In general, these products try to rehydrate the skin and thereby fill out the wrinkles, and some stimulate peel growth using hormones and growth factors. Additionally, invasive techniques include collagen injections to plump the tissue and injections of BOTOX® (the proper name brand of the botulinum neurotoxin) that paralyze the muscles that crease the peel and cause wrinkling.
Vitamin D Synthesis
The epidermal layer of man peel synthesizes vitamin D when exposed to UV radiation. In the presence of sunlight, a course of vitamin Dthree chosen cholecalciferol is synthesized from a derivative of the steroid cholesterol in the pare. The liver converts cholecalciferol to calcidiol, which is then converted to calcitriol (the active chemical form of the vitamin) in the kidneys. Vitamin D is essential for normal absorption of calcium and phosphorous, which are required for salubrious bones. The absence of lord's day exposure can pb to a lack of vitamin D in the torso, leading to a condition called rickets, a painful condition in children where the bones are misshapen due to a lack of calcium, causing bowleggedness. Elderly individuals who endure from vitamin D deficiency can develop a condition chosen osteomalacia, a softening of the bones. In nowadays day lodge, vitamin D is added as a supplement to many foods, including milk and orange juice, compensating for the need for sun exposure.
In improver to its essential office in bone health, vitamin D is essential for full general immunity confronting bacterial, viral, and fungal infections. Recent studies are also finding a link betwixt insufficient vitamin D and cancer.
Source: https://openstax.org/books/anatomy-and-physiology/pages/5-3-functions-of-the-integumentary-system
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