10/24/2019NursingABC - Module1/19Anatomy of the Integumentary SystemNotice:To optimize your learning in this course, we advise that you complete the labs and modules asindicated in the BIOD 151 Lab Schedule.Introduction to the Integumentary SystemThe Integumentary systemis comprised of theskin, hair and nails.Skinis the largest organ of the body. It ismade up of theepidermis(outer layer)dermis(middle layer) and thehypodermis(inner, also calledsubcutaneoustissue layer). SeeFigure 7.1, below to see the three layers of the skin. Skin cells absorbultraviolet radiation to produce vitamin D, which is used to promote bone development. The integumentarysystem contains the sensory receptors and glands used for protection of the skin and underlying tissues. Theintegumentary system plays an important role in protecting internal organs from extreme temperature changesas well as pathogenic (disease-causing) microorganisms. If the integumentary system is damaged andmicrobes or foreign objects make their way into the body, it is thelymphatic systemthat is responsible formounting the attack to defend the body’s internal environment.Figure 7.1 The three layers of the skin: epidermis, dermis and hypodermis.The epidermis is adhered tothe basement membrane (highlighted in blue).Sensory organs
10/24/2019NursingABC - Module2/19The skin contains several types of sense organs, each one specialized to detect a certain type of sensory input(Figure 7.2).Merkel’s cellsandMeissner's corpusclesaremechanoreceptorswhich detect mechanicalsensory information in the form of light touch and vibration.Nociceptorsdetect pain, such as from a pin prick.Pacinian corpusclesdetect the mechanical sensory information of pressure applied to the skin.Thermoreceptorsdetect hot and cold. Sensory organs embedded in the skin are designed to detect sensoryinformation and then to relay that information to the brain. The brain then interprets the information to determinean appropriate response.Figure 7.2 Sensory organs embedded within the layers of the skin.GlandsRecallendocrine glandssecretehormoneswhich are secreted in the bloodstream for body-wide distribution.Exocrine glandscontain secretions which are released through aduct(opening) into an epithelial surface orlining. Exocrine gland secretions can also release their contents onto the surface of the skin. Other types ofexocrine glands release their contents into an epithelial surface. (Recall, for example, that salivary amylase isreleased into the mouth.)Exocrine glands can be categorized by their shape and structure. Most glands in the body aremulticellularglands, which are set within epithelial tissue and release their contents through a duct to the surface.