CMU GENERAL BIOLOGY 2 THE INTEGUMENTARY SYSTEM Ge n e r al B i ol ogy2 Activity 5. THE INTEGUMENTARY SYSTEM DATA SHEET I. OBSERVATIONS: (simply fill up the tables) (15 pts) Table 1. Sensitivity to Mechanical Touch Body parts Degree of Sensitivity (rate from 1-5; 5 as most sensitive) 1 2 3 4 5 back (dorsal part) of your hand / palm / tip of index finger / back of wrist / ventral part of wrist / forearm / apple of the cheek / center of forehead / ear lobule / knee / dorsal part of foot / tip of big toe / sole of foot / stomach / lower back / Table 2. Sensitivity to Temperature (Hot) Body parts back (dorsal part) of your hand palm tip of index finger back of wrist ventral part of wrist forearm apple of the cheek center of forehead ear lobule knee dorsal part of foot tip of big toe sole of foot stomach lower back Degree of Sensitivity (rate from 1-5; 5 as most sensitive) 1 2 3 4 5 / / / / / / / / / / / / / / / Table 3. Sensitivity to Temperature (Cold) Body parts Degree of Sensitivity (rate from 1-5; 5 as most sensitive) 1 2 3 4 5 back (dorsal part) of your hand / palm / tip of index finger / back of wrist / ventral part of wrist / forearm / P age1of 1 Ge n e r al B i ol ogy2 apple of the cheek center of forehead ear lobule knee dorsal part of foot tip of big toe sole of foot stomach lower back / / / / / / / / / ILLUSTRATIONS OF THE HUMAN SKIN: (10 pts) II. DISCUSSIONS: 1. What is a skin? (2 pts) -The skin is a vital organ that covers the entire outside of the body, forming a protective barrier against pathogens and injuries from the environment. The skin is also the body's largest organ, covering the entire outside of the body. 2. What makes the skin sensitive to environmental stimuli? Are all parts of your skin of the same degree of sensitivity to the different stimuli? Explain. (2 pts) -The skin is sensitive to many different kinds of stimuli, such as touch, pressure, and temperature because there are different types of receptors found on the skin. These receptors are not distributed in a uniform way around the body that in some places such as the fingers and lips have more touch receptors than the other parts of the body. P age2of 2 Ge n e r al B i ol ogy2 3. Enumerate the different parts of the human skin and give their main function. Tabulate. (10 pts) Parts of the skin Functions Epidermis The epidermis is the outermost layer of skin that provides a waterproof barrier and creates our skin tone. Stratum corneum It serves as the primary barrier between the body and the environment. Stratum lucidum Found on thick skins, stratum lucidum protects the skin in areas most common to damage, such as the palms of the hands, the side of the fingers attached to the palms, and the bottoms of the feet. Stratum granulosum Stratum granulosum help to form a waterproof barrier that functions to prevent fluid loss from the body. Stratum spinosum The main function of the stratum spinosum is to allow keratinocytes (cells that produce keratin) to mature. Stratum basale The two functions of the stratum basale are proliferation and attachment of the epidermis to the dermis. Dermis The main functions of the dermis are protection, cushioning the deeper structures from mechanical injury, providing nourishment to the epidermis and playing an important role in wound healing. Papillary dermis The papilliary dermis supports the avascular epidermis with vital nutrients and provides a network for thermoregulation. Reticular dermis It strengthens the skin, providing structure and elasticity. It also supports other components of the skin, such as hair follicles, sweat glands, and sebaceous glands. Hypodermis The subcutaneous fat layer is the deepest layer of skin. It consists of a network of collagen and fat cells. It helps conserve the body's heat and protects the body from injury by acting as a shock absorber. 4. What are specialized structures of the human skin? Where do they originate? What are their functions. Tabulate. (10 pts) Specialized Origins Functions Structures Basket cells Basket Cells originate from the Basket cells can sense pressure and they are external granular layer. evaluated when assessing overall nerve health and condition. Blood Vessels Angiogenesis is initiated by the Blood vessels carry nutrients and oxygen-rich spontaneous dividing of tumor blood to the cells that make up the layers of cells due to a mutation, thus skin and carry away waste products. forming new blood vessels. Hair Erector Hypodermis. The arrector pili muscle is a tiny muscle Muscle connected to each hair follicle and the skin. (Arrector Pili When it contracts it causes the hair to stand Muscle) erect, and a "goosebump" forms on the skin. Hair Follicle It is located in the epidermis and The hair follicle is a tube-shaped sheath that the dermis. surrounds the part of the hair that is under the skin and nourishes the hair. Hair Shaft In the hair bulb, living cells The primary purpose for this is to trap a layer of divide and grow to build the hair air to add insulation. shaft. P age3of 3 Ge n e r al B i ol ogy2 Langerhans Cells Melanocyte Cells Merkel Cells The Langerhans cells originate from the bone marrow and then migrate into the epithelium. Melanocyte cells originate from embryonic cells named neural crest cells (NCC). Research suggests that they may be derived from pluripotential stem cells of the dermis or, as an alternative, from neural crest cells. Pacinian Corpuscle Pacinian corpuscle from nerve endings. Sebaceous Glands Sebaceous glands develops from the epithelial cells of the hair follicle. Sensory Nerves The neural crest cells are the origin of the sensory nerves. Stratum Corneum Stratum Corneum is made up of mostly keratin and lipids and marks the final stage of keratinocyte maturation and development. Sweat Gland (Sudoriferous Gland) Fibroblasts originated Epidermis. Fibroblasts are derived primitive mesenchyme. from These cells attach themselves to antigens that invade damaged skin and alert the immune system to their presence. A melanocyte is a cell that produces melanin, and is located in the basal layer of the epidermis. Merkel cells provide information on pressure, position, and deep static touch features such as shapes and edges. They are tactile sensors in the business of mechanotransduction. They encode surface features of touched objects into perception, but also have to do with proprioception. A pacinian corpuscle is a nerve receptor located in the subcutaneous fatty tissue that responds to pressure and vibration. Sebaceous glands are small, sack-shaped glands which release an oily substance onto the hair follicle that coats and protects the hair shaft from becoming brittle. These nerves sense and transmit heat, pain, and other noxious sensations. When they are not functioning properly sensations such as numbness, pins-and-needles, pain, tingling, or burning may be felt. When evaluating a skin biopsy, total number, contiguity, diameter, branching, swelling, and overall health of the sensory nerves are assessed. It protects the living cells beneath it by providing a tough barrier between the environment and the lower layers of the skin. The stratum corneum is useful for diagnosis because in some conditions it will become thinner than normal. These glands are located in the epidermis and produce moisture (sweat) that is secreted through tiny ducts onto the surface of the skin (stratum corneum). When sweat evaporates, skin temperature is lowered. Its main function is to synthesise collagen, elastin and the viscous gel within the dermis. 5. How does the human skin protect the body from the environment? Give the structures that contribute to the skin’s protective function. (5 pts) -The skin provides a protective barrier from the external environment, it includes structures that have own unique characteristic that contributes to the overall protection of the body. The epidermis provides a waterproof barrier, protects the skin from UV radiation, and losing important nutrients and water. The dermis nourishes epidermis and play an important role on wound healing. The hypodermis provides the main structural support for the skin, as well as insulating the body from cold and aiding shock absorption. The Langerhans cells keeps the dangerous microbes from entering the body by protecting the skin from infection and also by stimulating allergic reactions. III. REFERENCES: (2 pts) Science World. (n.d.). Tactile Sensitivity. https://www.scienceworld.ca/resource/tactile-sensitivity/ Neuroscience For Kids . (n.d.). Touch Experiments. Retrieved Retrieved from from P age4of 4 Ge n e r al B i ol ogy2 https://faculty.washington.edu/chudler/chtouch.html Pinterest. (n.d.). The Structure and Function https://www.pinterest.ph/pin/524950900307273279/ of the Skin. Retrieved from Wong, M. (n.d.). What body parts are exceptionally beautiful under a microscope?. Quora. Retrieved from https://www.quora.com/What-body-parts-are-exceptionally-beautiful-under-amicroscope Healthline. (2018, December 19). Epidermis Function: Get to Know Your Skin . Retrieved from https://www.healthline.com/health/epidermis-function NursingTimes. (2019, November 25). Skin 1: the structure and functions of the skin. Retrieved from https://www.nursingtimes.net/clinical-archive/dermatology/skin-1-the-structure-andfunctions-of-the-skin-25-11-2019/ P age5of 5
