包邮大学专业英语系列教材医学英语视听说(第2版大学专业英语系列教材)

Unit One Integumentary SystemThe finest clothing made is a person's own skin, but, of course, society demands something more than this. ――Mark Twain (1835―1910, American writer)Introductory Remarks The integumentary system is made up of skin, hair, nails, and exocrine glands. The major function of the system is the protection that the skin gives to underlying tissues. Skin, only a few millimeters thick, is the largest organ in the body. It keeps most harmful substances out, as well as prevents the loss of body fluids. Extending from the skin, hair and nails reinforce the skin and protect it from environmental damage. The exocrine glands of the integumentary system produce sweat, oil, and wax to cool, protect, and moisturize the skin's surface.Part I Introduction to the Integumentary SystemThink and TalkDirections: Skin is the largest organ in our body. Do you know its major functions? How does it protect us against threats from the outside world? Discuss the questions with your partner with the help of the following words.epidermis dermis waterproof microbe T-cellbacteria fungi gland sebum sensationWatch and DoTask One: Blank FillingDirections: Watch the video and fill in the blanks according to what you've heard. Between you and the rest of the world lies an (1) that makes up 16% of your physical weight. This is your skin, the largest organ in your body: laid out flat, it would cover close to 1.7 square meters of ground. Its purpose may seem obvious―to keep our (2) in. But a look beyond the surface (3) that it plays a surprising number of roles in our lives. First, the basics. Skin is the foundation of the integumentary system, which also (4) your hair, nails, and specialized (5) and nerves. Made up of three layers, the epidermis, dermis, and hypodermis, skin’s (6) varies from 0.5 millimeters at its hinnest and up to four millimeters at its thickest. It also carries out three key functions: protecting, regulating, and sensing the world beyond its limits. On a daily basis, its huge surface processes hundreds, if not thousands, of physical (7) , relying mostly on large, pressure-sensitive skin components called Merkel cells. In your fingertips alone, there are 750 Merkel cells per each square-centimeter of skin, coupled with over 2,500 receptors that give you your sense of (8) . This surface is also the body's first major line of defense. Without it, you’d be a soggy mass of tissue and fluids, fatally exposed to the elements. Skin effectively (9) off your insides and also absorbs pressure and shock with flexible collagen that makes up most of its (10) layer.Task Two: Multiple ChoiceDirections: Watch the video again and pick the best answer from the choices marked A, B, C and D.1. We rely on ( ) to give us our sense of touch.A. the skin’s surface areaB. the sensitive hairs on the surface of our skinC. flexible collagen fibersD. Merkel cells and receptors2. The epidermis is made up mainly of ( ) .A. hardened protein called keratinB. keratinocytes replaced every four weeksC. cells and microbesD. Langerhans cells3. ( ) ensure that the immune system is ready to react when the body is at risk.A. T-cells B. Bacteria that inhabit the skinC. Fungi that inhabit the skinD. Thousand species of skin microbes including bacteria and fungi4. About ( ) of the body’s blood supply is circulating through the dermis at any given time.A. 15% B. 25% C. 50% D. 17%5. The average human has 5 million hair follicles on ( ) .A. the scalpB. the bodyC. the body except the palms of hands and soles of feetD. the scalp, palms of hands and soles of feetTask Three: Description Directions: Make a brief description of the integumentary system according to what you've heard.