8/20/20207.1: Anatomy of the Integumentary System: Essential Human Anatomy and Physiology I with Lab- Keck1/127.1: Anatomy of the IntegumentarySystemNotice:To optimize your learning in this course, we advise that you complete thelabs and modules as indicated in the BIOD 151 Lab Schedule.Introduction to the Integumentary SystemThe integumentary systemis comprised of theskin, hair, and nails.Skinis thelargest organ of the body. It is made up of theepidermis(outer layer),dermis(middle layer), and thehypodermis(inner, also calledsubcutaneoustissue layer).SeeFigure 7.1below to see the three layers of the skin. Skin cells absorb ultravioletradiation to produce vitamin D, which is used to promote bone development. Theintegumentary system contains the sensory receptors and glands used for protectionof the skin and underlying tissues. The integumentary system plays an importantrole in protecting internal organs from extreme temperature changes as well aspathogenic (disease-causing) microorganisms. If the integumentary system isdamaged and microbes or foreign objects make their way into the body, it is thelymphatic systemthat is responsible for mounting the attack to defend the body’sinternal environment.
8/20/20207.1: Anatomy of the Integumentary System: Essential Human Anatomy and Physiology I with Lab- Keck2/12Figure 7.1 The three layers of the skin: epidermis, dermis, and hypodermis.The epidermis is adhered to the basement membrane (highlighted in blue).Sensory OrgansThe skin contains several types of sense organs, each one specialized to detect acertain type of sensory input(Figure 7.2).Merkel’s cellsandMeissner'scorpusclesaremechanoreceptorsthat detect mechanical sensory information inthe form of light touch and vibration.Nociceptorsdetect pain, such as from a pinprick.Pacinian corpusclesdetect the mechanical sensory information of pressureapplied to the skin.Thermoreceptorsdetect hot and cold. Sensory organsembedded in the skin are designed to detect sensory information and then to relaythat information to the brain. The brain then interprets the information to determinean appropriate response.
8/20/20207.1: Anatomy of the Integumentary System: Essential Human Anatomy and Physiology I with Lab- Keck3/12Figure 7.2 Sensory organs embedded within the layers of the skinGlandsRecallendocrine glandssecretehormones,which are secreted in the bloodstreamfor body-wide distribution.Exocrine glandscontain secretions released through aduct(opening) into an epithelial surface or lining. Exocrine gland secretions can alsorelease their contents onto the surface of the skin. Other types of exocrine glands