BIOL 235 Chapter 5 (A+ Graded solutions)

Functions of the integumentary system correct answers 1. Regulates body temperature 2. Stores blood 3. Protects body from external environment 4. Detects cutaneous sensations from surrounding environment - pain/ pleasure 5. Excretes and absorbs substances 6. Synthesizes vitamin D What is the integumentary system composed of correct answers skin, hair, sweat glands, nails, sensory receptors Skin correct answers - cutaneous membrane, covers the external surface of the body and is the largest organ of the body in both surface area and weight. (7% of body weight). - location of skin makes it vulnerable to damage from trauma, sunlight, microbes, and pollutants in the environment, but skin's protective features ward off such damage What does the skin reflect? correct answers Skin can reflect our emotions (frowning, blushing) and some aspects of normal physiology (sweating). Changes in skin color can indicate homeostatic imbalances in the body. Ex: bluish skin color associated with hypoxia (oxygen deficiency) Dermatology correct answers medical specialty that deals with the structure, function, and disorders of the integumentary system. Two main parts of skin correct answers 1. Epidermis: superficial, thinner portion, composed of epithelial tissue. Avascular, no bleeding when cut. 2. Dermis: deeper, thicker connective tissue portion. Vascular, bleeding if cut. Subcutaneous (subQ) layer or hypodermis correct answers Consists of areolar and adipose tissue. Fibers that extend from the dermis anchor the skin to the subcutaneous layer, which in turn attaches to underlying - fascia (connective tissue around muscles and bones). Serves as a storage depot for fat and contains large blood vessels that supply the skin Also contains nerve endings called lamellated corpuscles or pacinian corpuscles that are sensitive to pressure. Epidermis correct answers composed of keratinized stratified squamous epithelium. contains four principal types of cells: keratinocytes, melanocytes, Langerhans cells (Intraepidermal macrophages) and Merkel cells (Tactile epithelial cells) Keratinocyte correct answers 90% of epidermal cells arranged in four or five layers and produce the protein keratin. also produces lamellar granules, which is release a water-repellent sealant that decreases water entry and loss and inhibits the entry of foreign materials.