Integumentary System (CN 100 Anatomy & Physiology) PDF

CHAPTER III: INTEGUMENTARY SYSTEM The integumentary system refers to the skin and its accessory structures, and it is responsible for much more than simply lending to your outward appearance. In the adult human body, the skin makes up about 16 percent of body weigh...

CHAPTER III: INTEGUMENTARY SYSTEM The integumentary system refers to the skin and its accessory structures, and it is responsible for much more than simply lending to your outward appearance. In the adult human body, the skin makes up about 16 percent of body weight and covers an area of 1.5 to 2 m2. In fact, the skin and accessory structures are the largest organ system in the human body. As such, the skin protects your inner organs and it is in need of daily care and protection to maintain its health. This chapter is divided into three (3) lessons. LESSON 1: FUNCTION OF THE INTEGUMENTARY SYSTEM LESSON 2: STRUCTURES OF THE SKIN LESSON 3: ACCESSORY SKIN STRUCTURES In this chapter, you will learn about the functions of the integumentary system, the structures of skin which are the dermis and epidermis and the accessory skin structures. After studying this chapter, you must have: a. Described the functions of integumentary system, b. Identified the structures of skin, and c. Identified the different accessory skin structures. LESSON 1. FUNCTIONS OF THE INTEGUMENTARY SYSTEM In this section you will learn about the functions of the integumentary system, the structures of skin which are the dermis and epidermis and the accessory skin structures. After studying the section, you must have: a. Described the different functions of the skin and structures that enable them b. Explained how the skin helps maintain body temperature  CN 100 ANATOMY & PHYSIOLOGY: CHAPTER 3 INTEGUMENTARY SYSTEM WARM-UP ACTIVITY Pre-Test : Check your knowledge before the lesson. Choose the letter of the best answer. Write the chosen letter on a separate sheet of paper. 1. In humans, exposure of the skin to sunlight is required for ________. a. arteriole constriction b. thermoregulation c. vitamin D synthesis d. folate production 2. One of the functions of the integumentary system is protection. Which of the following does not directly contribute to that function? a. folic acid synthesis b. Merkel cells c. Desmosomes d. stratum lucidum 3. The ability of the integumentary system to receive information from the external environment is called a. A protective layer b. Sensation c. Temperature Regulation d. Vitamin D Synthesis CENTRAL ACTIVITIES INTEGUMENTARY SYSTEM The integumentary system (inte- = whole; gument- = body covering) consists of the skin and its derivatives— hair, nails, glands, and receptors. This system provides a protective barrier for the body, contains cutaneous sensory receptors, aids in the production of vitamin D, is important in regulating body temperature, and plays a minor role in excretion and absorption. The skin is classified as an organ because it has many types of tissues that work together to perform specific functions. The skin is also known as the integument or cutaneous membrane. GENERAL FUNCTIONS OF THE INTEGUMENTARY SYSTEM The integument is more than just a wrapping around the body. It serves many varied functions, including protection, prevention of water loss, temperature regulation, metabolic regulation, immune defense, sensory reception, and excretion. 1. Protection. It guards the body’s physical and biochemical integrity. Mariano Marcos State University College of Health Sciences 2 Department of Nursing  CN 100 ANATOMY & PHYSIOLOGY: CHAPTER 3 INTEGUMENTARY SYSTEM  The intact skin with its lipid plays an important role in preventing water loss.  It prevents the entry of microorganisms and other foreign substances into the body  Secretions from skin glands (oily sebum) provide an inappropriate environment for some microorganisms  Defense against abrasion due to the stratified squamous epithelium comprising the skin  Melanin absorbs UV light protecting underlying structures from its damaging effects  Hair act as heat insulator (head), keep sweat out of the eyes (eyebrows), protect eyes from foreign object (eyelashes), prevent entry of dust and other materials (nose and ears)  Nails protect the ends of the digits from damage and a useful tool for defense 2. Sensation. Provides sensory information about the external environment.  Has receptors in the epidermis and dermis that detects:  pain, heat, cold – Free nerve endings Corpuscle  and deep pressure/ vibration – Pacinian Corpuscle  Light touch – Merkel’s Corpuscle  Movement of hair can be detected by sensory receptors around the hair follicles 3. Vitamin D production. Synthesis of vitamin D requires activation of a precursor molecule in the skin by ultraviolet (UV) rays in sunlight  Vitamin D enhances the absorption of Calcium and Phosphate in the intestines, which are necessary for bone metabolism and muscle function.  Vitamin D is produced from the ergosterol in the skin when exposed to the UV light  synthesized by the liver  becomes CALCITROL, the most active form of Vitamin D 4. Temperature Regulation. It helps maintain a constant body temperature (370C).  With increase body temperature: blood vessels in the dermis dilate  increase blood flow to the skin  transfer heat through: radiation, convection, conduction, evaporation (sweat)  With decreased body temperature: blood vessels constrict  reduces blood flow to the skin  reduced heat loss 5. Excretion & absorption.  Excretion – does not play a significant role in excretion, sweat contains water, salt, and small amounts of urea, uric acid and ammonia.  Absorption  absorption of water-soluble substances are negligible  lipid-soluble materials do penetrate the skin  e.g. fat soluble Vitamins A,D,E,K, oxygen and carbon dioxide  toxic materials can also be absorbed through the skin Mariano Marcos State University College of Health Sciences 3 Department of Nursing  CN 100 ANATOMY & PHYSIOLOGY: CHAPTER 3 INTEGUMENTARY SYSTEM  e.g. organic solvents (acetone), carbon tetrachloride (dry-cleaning fluid), salt of heavy metals (lead, mercury and arsenic), toxins in poison ivy and oak 6. Secretion. Of substances like sebum/sweat.  Skin exhibits an excretory function when it secretes substances from the body during sweating. Sweating, or sensible perspiration occurs when the body needs to cool itself off.  The skin contains sebaceous glands that secrete an oily material called sebum, which lubricates the skin surface and hair. 7. Immunity. Contains cells which are capable of phagocytosis that prevent the entrance of harmful elements.  The epidermis contains a small population of immune cells. These immune cells (derived from a type of white blood cell), called epidermal dendritic cells, or Langerhans cells, play an important role in initiating an immune response by phagocytizing pathogens that have penetrated the epidermis and also against epidermal cancer cells. 8. Blood reservoir. Skin house 1/3 of blood vessels supplying the body WRAP -UP ACTIVITY The skin and accessory structures perform a variety of essential functions, such as protecting the body from invasion by microorganisms, chemicals, and other environmental factors; preventing dehydration; acting as a sensory organ; modulating body temperature and electrolyte balance; and synthesizing vitamin D. The underlying hypodermis has important roles in storing fats, forming a “cushion” over underlying structures, and providing insulation from cold temperatures. ACTIVITY 1. Test your knowledge! Before we move on to the next section, it’s time for you to evaluate first what you have learned by answering the following questions. Are you ready? Let’s get going! You will find the Answer Key at the end of the lesson. WHAT DID YOU LEARN? 1. What is the relationship between exposure to sunlight and the body’s need for vitamin D? 2. Why do people sweat excessively when exercising outside on a hot day? 3. Explain your skin’s response to a drop in body core temperature. WHAT DO YOU THINK? During the Industrial Revolution, as children spent little time outdoors and most of their time working in factories, increasing numbers of them developed a bone Mariano Marcos State University College of Health Sciences 4 Department of Nursing  CN 100 ANATOMY & PHYSIOLOGY: CHAPTER 3 INTEGUMENTARY SYSTEM disorder called rickets. Rickets is caused by inadequate vitamin D. Based on your knowledge of skin function, why do you think these children developed rickets? LESSON 2. STRUCTURES OF THE SKIN In this section you will learn about the different structures of the skin. After studying the section, you must have: a. Identified the components of the integumentary system b. Described the layers of the skin and the functions of each layer c. Described the role of keratinocytes and their life cycle d. Described the role of melanocytes in skin pigmentation WARM-UP ACTIVITY SHORT FILM- VIEWING View this animation to learn more about layers of the skin. What are the basic functions of each of these layers? (https://ebsco.smartimagebase.com/skin-layers-and-functions/view-item?ItemID=71995) CENTRAL ACTIVITIES A. SKIN  Largest organ in the body in terms of surface area and weight.  Occupies almost 2sg.m. (18-22 ft2) = 3000 sg. in. TBSA  wt.=4.5-5 kg. (10-11lbs) or 7% of the TBW  thickness = 0.5mm (eyelids) – 4mm (heels), 1-2mm thick in most of the body  DERMATOLOGY (dermat-=skin; -ology=study of) – branch of medicine that specializes in diagnosing and treating skin disorders Mariano Marcos State University College of Health Sciences 5 Department of Nursing  CN 100 ANATOMY & PHYSIOLOGY: CHAPTER 3 INTEGUMENTARY SYSTEM Figure 1. Components of the Integumentary System Photo credit: PAP © 2018. © Elaine Marieb, Suzanne Keller, Pearson Education, Inc.  Elastic- contains collagen fibers  Made of rugged contours  Self-regenerating – every 2 weeks  The skin consists of two main parts: 1. EPIDERMIS – outer, thinner, composed of epithelial tissue 2. DERMIS – inner, thicker composed of connective tissue Mariano Marcos State University College of Health Sciences 6 Department of Nursing  CN 100 ANATOMY & PHYSIOLOGY: CHAPTER 3 INTEGUMENTARY SYSTEM 1. EPIDERMIS  Made up of keratinized stratified squamous If you cut the epithelium epidermis, there is no  AVASCULAR = contains no blood vessels bleeding, but if the cut  Site for Keratinization = generation of new penetrates to the cells in which the composition and shape dermis there is bleeding. changes.  Contains FOUR PRINCIPAL TYPES OF CELLS: a. KERATINOCYTES (keratino- = hornlike; -cytes = cells)  90% of epidermal cells  Produce the protein keratin – tough, fibrous protein that helps protect the skin and underlying tissues from heat, microbes and chemicals.  Produce lamellar granules – release a waterproofing sealant Figure 2. Cells in the epidermis Photo credit: PAP © 2014. © Gerard J. Tortora, 7 L.L.C., Bryan Derrickson, John Wiley & Sons, Inc. Mariano Marcos State University College of Health Sciences Department of Nursing  CN 100 ANATOMY & PHYSIOLOGY: CHAPTER 3 INTEGUMENTARY SYSTEM b. MELANOCYTES (melano- = black)  8% of epidermal cells  Produce melanin – brown-black pigment influencing the skin color and absorbs damaging UV rays/light HOW? When UV rays struck the keratinocytes, melanin granules cluster together forming a protective veil over the nucleus on the side toward the skin surface shielding the nuclear DNA from the UV light.  Have long, slender projections extending between the keratinocytes and transfer melanin granules to them. c. LANGERHANS CELLS  Arise from red bone marrow and migrate to the epidermis  Constitute a small portion of the epidermal cells  Participate in immune responses against microorganisms that invade the skin  Easily damaged by UV light d. MERKELL CELLS  Least numerous of the epidermal cells  Located in the deepest layer of the epidermis  Contacts with Tactile (Merkel) Disc – flattened process of a sensory neuron  Merkel cells and tactile discs function in the sensation of touch The epidermis has several layers. Most parts of the body have four layers (thin skin). Other areas where exposure to friction is greatest (fingertips, palms and soles), has five layers of the epidermis (thick skin). LAYERS OF THE EPIDERMIS: (outer-inner) 1. STRATUM CORNEUM (corne- = hard/hooflike)  Outermost layer of the epidermis  Flat, thick layer of dead cells arranged in parallel rows around 25-30 layers  Composed of dead squamous cornified cells  Contains soft keratin/keratohyalin and densely packed intermediate filaments  Aka horny layer  Water repellent layer – with the aid of lipids from lamellar granules between the cells  Also a barrier against injury and microorganisms.  Continuously shed and replaced by deeper strata CALLUS – an abnormal thickening of the epidermis formed by constant exposure to friction 2. STRATUM LUCIDUM (lucid-= clear)  Watery/clear layer  Flat translucent layer of dead cells/dying cells consisting of 3-5 layers Mariano Marcos State University College of Health Sciences 8 Department of Nursing  CN 100 ANATOMY & PHYSIOLOGY: CHAPTER 3 INTEGUMENTARY SYSTEM  Contains densely packed intermediate filaments and thickened plasma membranes  Contains protein – ELEIDIN – transitional substance between soft keratin and keratohyalin  Location: fingertips, palms and soles Figure 3. Layers of the Epidermis Photo credit: https://courses.lumenlearning.com/ 3. STRATUM GRANULOSUM (granulos-= little grains)  Granular layer – consist of granules, darkly stained (KERATOHYALIN)  Keratohyalin organize intermediate filaments into even thicker bundles  Also has LAMELLAR GRANULES – release lipid rich secretion that fills the spaces between cells of the epidermis.  Lipid-rich secretion – a water-repellant sealant that retards loss of body fluids and entry of foreign materials.  Consist of 3-5 layers of flattened keratinocytes that are undergoing APOPTOSIS. Mariano Marcos State University College of Health Sciences 9 Department of Nursing  CN 100 ANATOMY & PHYSIOLOGY: CHAPTER 3 INTEGUMENTARY SYSTEM  APOPTOSIS – nuclei and organelles of the cells begin to degenerate and intermediate filaments become apparent  nuclei breakdown  cells can no longer carry on vital metabolic reaction  they die  Marks the transition between the deeper, metabolically active strata and the dead cells of the more superficial strata. 4. STRATUM SPINOSUM (spinos-= thornlike)  Prickle cell – consist of prickly layers  Composed of 8-10 layers of polyhedral (many-sided) keratinocyte cells which have spines protruding into the surface  Appear to be covered with thornlike spines when placed under a microscope because they shrink and pull apart, although they are rounded and larger in living tissue.  Some cells are formed here and are pushed to the surface – some cells have the same organelles as the cells in the stratum basale retaining their ability to divide.  Provides both strength and flexibility to the skin – at each spine-like projections, bundles of intermediate filaments of the cytoskeleton insert into desmosomes, tightly joining the cells to one another.  Projections of both langerhans cells and melanocytes also appear in this strata. 5. STRATUM BASALE/STRATUM GERMINATIVUM (basal-=base)/ (germ-= sprout)  Deepest layer of the epidermis  Usually a single layer/row of columnar/cuboidal keratinocytes cells, some of which are STEM CELLS  STEM CELLS undergo cell division to continually produce keratinocytes  Where melanin are being produced by melanocytes. – melanin has 3 types: yellow, brown, black  Has filaments that attach cells to desmosomes binding the cells to each other and to the adjacent stratum spinosum.  The filaments also attach to hemidesmosomes, binding the cells to the basement membrane between the epidermis and the dermis.  also has melanocytes, langerhans cells and merkell cells with tactile discs scattered among the keratinocytes. KERATINIZATION – a developmental process that newly formed cells in the stratum basale undergo as they are being pushed to the surface.  Lasts for four weeks in average 0.1mm thickness  As cells move from one epidermal cells to the next, they accumulate more keratin  undergo apoptosis keratinized cells slough off  replaced by underlying cells.  Regulation is not well understood but believed that the EPIDERMAL GROWTH FACTOR (EGF) plays a role) Mariano Marcos State University College of Health Sciences 10 Department of Nursing  CN 100 ANATOMY & PHYSIOLOGY: CHAPTER 3 INTEGUMENTARY SYSTEM 2. DERMIS  Inner layer, called CORIUM or TRUE SKIN  Second, deeper part of the skin  Mainly consist of connective tissue containing collagen and elastic fibers, few of which are fibroblasts, macrophage and some adipocytes  Embedded are blood vessels, nerves, glands and hair follicles  VASCULAR – contains blood vessels  2 DIVISIONS: a. PAPILLARY REGION  Superficial portion of the dermis  1/5 of the total thickness of the dermis  Sub-epithelial layer  So-named because of the presence of DERMAL PAPILLAE  DERMAL PAPILAE – small, finger-like projections that increase the surface area Nipples Indent the epidermis and contain loops of capillaries Give rise to fingerprints and footprints. Figure 5. Layers of the dermis 11 Photo credit:https://courses.lumenlearning.com/suny- Mariano Marcos State University ap1/chapter/layers-of-the-skin/ College of Health Sciences Department of Nursing  CN 100 ANATOMY & PHYSIOLOGY: CHAPTER 3 INTEGUMENTARY SYSTEM HOW? Epidermal ridges and grooves are formed on 3rd or 4th month of fetal life as the epidermis conforms to the dermal papillae  present in the palms, fingers, soles and toes  increase friction in hand and foot  increase grip of hand and foot o Ducts of sweat glands open to the epidermal ridges  sweat and ridges form fingerprints/ footprints when a smooth object is touched o Ridge pattern is genetically determined and unique for each individual b. RETICULAR REGION (reticul- = netlike)  Net-like layer  Deeper portion of the dermis  Made of dense connective tissue and collagenous fiber that crisscross/interlace in a netlike manner  Combination of the collagen and elastic fibers provides the skin with strength, extensibility (ability to stretch), and elasticity (ability to return to original shape after stretching) STRIAE (= streaks)/ stretch marks  small tears in the skin caused by extreme stretching described as red/silvery white streaks on the skin surface. CLEAVAGE/TENSION LINES  basis during operation; composed of collection of collagen fibers; provide strength for the dermis during operation. HYPODERMIS / SUBCUTANEOUS (SQ or SC)/ SUPERFICIAL FASCIA  not part of the integumentary system  attaches the skin to underlying bone or muscle  loose connective tissue that contain fat – functions as padding and insulation, and responsible for some of structural differences between men and women. SKIN COLOR  DETERMINED BY SEVERAL FACTORS: A. PIGMENT of the Skin  MELANIN = skin color variation Located mostly in the epidermis, causes skin color to vary from pale yellow to tan to black Melanocytes are plentiful in the mucus membranes, penis, nipples and areola of the breasts, face and limbs  CAROTENE = yellow-orange pigment Precursor of Vitamin A – used to synthesize pigments needed for vision Found in the stratum corneum and fatty areas of the dermis and hypodermis Mariano Marcos State University College of Health Sciences 12 Department of Nursing  CN 100 ANATOMY & PHYSIOLOGY: CHAPTER 3 INTEGUMENTARY SYSTEM B. Blood flow to the Skin  Hemoglobin- oxygen carrying pigment in RBC causes the red color of the skin  All races have = # of melanocytes  The color of the skin depends upon the amount of melanin produced by the melanocytes.  Factors affecting Melanin Production:  Genetic  Hormones – mask of pregnancy  Exposure to sunlight ALBINISM - is the inherited inability of an individual to produce melanin. Most albinos (person with albinism) people affected by albinism, have melanocytes that are unable to synthesize tyrosinase. Melanin is missing from their hair, eyes, and skin. This results in problems with vision and a tendency of the skin to burn easily on overexposure to sunlight. VITILIGO - the partial or complete loss of melanocytes from patches of skin produces irregular white spots. The loss of melanocytes may be related to an immune system malfunction in which antibodies attack the melanocytes. ACTIVITY 2. Test your knowledge! Before we move on to the next section, it’s time for you to evaluate first what you have learned by answering the following questions. Are you ready? Let’s get going! You will find the Answer Key at the end of the lesson. 1. The papillary layer of the dermis is most closely associated with which layer of the epidermis? a. Stratum spinosum b. Stratum corneum c. Stratum granulosum d. Stratum basale 2. Langerhans cells are commonly found in the ________. a. Stratum spinosum b. Stratum corneum c. Stratum granulosum d. Stratum basale 3. The papillary and reticular layers of the dermis are composed mainly of ________. a. melanocytes b. keratinocytes c. connective tissue d. adipose tissue Mariano Marcos State University College of Health Sciences 13 Department of Nursing  CN 100 ANATOMY & PHYSIOLOGY: CHAPTER 3 INTEGUMENTARY SYSTEM 4. Collagen lends ________ to the skin. a. elasticity b. structure c. color d. UV protection 5. Which of the following is not a function of the hypodermis? a. protects underlying organs b. helps maintain body temperature c. source of blood vessels in the epidermis d. a site to long- term energy storage WRAP-UP ACTIVITY The skin and its accessory structures make up the integumentary system, which provides the body with overall protection. The skin is made of multiple layers of cells and tissues, which are held to underlying structures by connective tissue. The deeper layer of skin is well vascularized (has numerous blood vessels). It also has numerous sensory, and autonomic and sympathetic nerve fibers ensuring communication to and from the brain How are you doing so far? Are you having fun yet? On to the next topic! LESSON 3. ACCESSORY SKIN STRUCUTRES In this section you will learn about the different accessory skin structures. After studying the section, you must have: a. Identified the accessory structures of the skin, b. Described the structure and functions of hair and nails c. Described the structure and function of the sweat and sebaceous glands. Mariano Marcos State University College of Health Sciences 14 Department of Nursing  CN 100 ANATOMY & PHYSIOLOGY: CHAPTER 3 INTEGUMENTARY SYSTEM WARM-UP ACTIVITY Pre - Test : Check your knowledge before the lesson. Choose the letter of the best answer. Write the chosen letter on a separate sheet of paper. 1. Which of the following is not a derivative of the skin? a. sweat glands b. oil glands c. hairs d. nails 2. Which of the following is not a function of hair? a. Keep us warm b. Senses insect on the skin before they bite c. Shield the eyes d. Initiates sweat glands 3. Which of the following structures do not make up the major regions of the hair shaft? a. Medulla b. Cortex c. Hair follicle d. Cuticle CENTRAL ACTIVITIES II. SKIN DERIVATIVES A. HAIR or PILI  Each hair is composed of columns of dead, keratinized epidermal cells bonded together by extracellular proteins. 1. SHAFT  superficial portion of the hair 2. ROOT  portion deep to the shaft, penetrating the dermis or SC layer 3. HAIR FOLLICLE  surrounds the root of the hair. Made of external & internal root sheath Mariano Marcos State University College of Health Sciences 15 Department of Nursing  CN 100 ANATOMY & PHYSIOLOGY: CHAPTER 3 INTEGUMENTARY SYSTEM Figure 6. Hair Photo credit: PAP © 2014. © Gerard J. Tortora, L.L.C., Bryan 4. BULB  onion-shaped structure at the base of each hair follicle; houses the papilla of the hair and contains the matrix 5. ARRECTOR PILI MUSCLE  contractpulls the hair shaft ”goose bumps”/ “gooseflesh”  Under physiological or emotional stress, such as cold or fright, autonomic nerve endings stimulate the arrector pili muscles to contract, which pulls the hair shafts perpendicular to the skin surface. This action causes “goose bumps” or “gooseflesh” because the skin around the shaft forms slight elevations. Mariano Marcos State University College of Health Sciences 16 Department of Nursing  CN 100 ANATOMY & PHYSIOLOGY: CHAPTER 3 INTEGUMENTARY SYSTEM  the root & shaft consist of 3 LAYERS: 1. MEDULLA = forms the central core;  contains soft keratin,  pigment granules and air spaces 2. CORTEX = thickest layer, forms the major part of the shaft;  hard portion surrounding the medulla,  containing pigment granules in dark hair but mostly air in gray or white hair 3. CUTICLE = made up of thin squamous cells,  mostly heavily keratinized,  that overlap to create a scale-like appearance,  their free edges pointing toward the end of the hair HAIR COLOR = due to melanin (amount & type) 1. dark-colored hair – true melanin 2. blond & red hair – variants of melanin, Iron and more Sulfur 3. graying hair – due to progressive decline in tyrosinase 4. white – results from accumulation of air bubbles in the medullary shaft A. GLANDS several kinds of exocrine glands are associated with the skin: 1. SEBACEOUS/OIL GLANDS  simple, branched acinar glands, connected to hair follicles.  secreting portion lies in the dermis, opens into the neck of the hair follicle.  some open directly onto the surface of the skin (e.g. lips, glans penis, labia minora, tarsal glands of the eyelids)  SEBUM  oily substance secreted by the sebaceous glands  mixture of fats, cholesterol proteins, inorganic salts and pheromones  keeps hair from drying and becoming brittle  prevents excessive evaporation of water from the skin, making the skin soft and pliable  inhibit growth of certain bacteria 2. SWEAT/SUDORIFEROUS GLANDS  Release their secretion via exocytosis empty secretion onto the skin surface  pores/hair follicles Divided into 2 MAIN TYPES: Mariano Marcos State University College of Health Sciences 17 Department of Nursing  CN 100 ANATOMY & PHYSIOLOGY: CHAPTER 3 INTEGUMENTARY SYSTEM A. ECCRINE/MEROCRINE SWEAT GLANDS  distributed all over the body (skin of the forehead, palms & soles) except: margins of the lips, nailbeds of fingers & toes, glans penis, glans clitoris, labia minora & eardrum  simple, coiled tubular glands, more common than the apocrine sweat glands.  secretory portion is mostly located in the deep dermis/upper SC layer  Excretory duct projects through the dermis & epidermis and ends as a pore at the end of the epidermis  Produces sweat = 600ml/day  Components; water, ion (Na & Cl), urea, uric acid, ammonia, amino acids, glucose, lactic acid.  Help regulate body temperature via evaporation  INSENSIBLE PERSPIRATION = sweat that evaporated from the skin before it is perceived as moisture  SENSIBLE PERSPIRATION = sweat that is excreted in larger amounts & is perceived as moisture on the skin B. APOCRINE SWEAT GLANDS  Found mainly in the skin of: axilla/armpit, groin, areola, bearded regions of the face  Secretion released by exocytosis, slightly viscous with the same component as eccrine glands + lipid and proteins  Women = glands enlarge at ovulation period and shrink back during menstruation  Only start to function at puberty stage  Stimulated during emotional stress and sexual excitement, whereas these secretions are commonly known as “cold sweat”  CERUMINOUS GLANDS - modified sweat glands in the external ear, producing waxy secretions known as CERUMEN or EARWAX. Mariano Marcos State University College of Health Sciences 18 Department of Nursing  CN 100 ANATOMY & PHYSIOLOGY: CHAPTER 3 INTEGUMENTARY SYSTEM Table 1: Summary of Skin FEATURE SEBACIOUS ECCRINE SWEAT APOCRINE CERUMINOUS Photo credit: PAP © 2014. © Gerard J. Tortora, GLANDS L.L.C., Bryan Derrickson, GLANDS John Wiley & Sons, Inc. SWEAT GLANDS GLANDS Distribution Largely in lips, glans Throughout skin of Skin of axillae, External auditory penis, labia minora, most groin, areolae, canal and tarsal glands; regions of body, bearded regions small in trunk and especially skin of face, limbs; of forehead, palms, clitoris, and labia absent in palms and and soles. minora. soles. Location of Dermis. Mostly in deep Mostly in deep Subcutaneous secretory dermis (sometimes dermis and upper layer. portion in upper subcutaneous subcutaneous layer. layer). Termination of Mostly connected Surface of Surface of Surface of excretory duct to hair epidermis. epidermis. external auditory follicle. canal or into ducts of sebaceous glands. Secretion Sebum (mixture of Perspiration, which Perspiration, Cerumen, a waxy triglycerides, consists which consists of material. cholesterol, of water, ions (Na_, same proteins, and Cl_), urea, uric acid, components as inorganic salts). ammonia, eccrine sweat amino acids, glands plus lipids glucose, and and proteins. lactic acid. Functions Prevent hairs from Regulation of body Stimulated Impede entrance drying out, prevent temperature, waste during emotional of foreign bodies water loss from removal, stress and sexual and insects into skin, keep skin soft, stimulated during excitement. external ear canal, inhibit growth emotional stress. waterproof canal, of some bacteria. prevent microbes from entering cells. Onset of Relatively inactive Soon after birth. Puberty. Soon after birth. function during childhood; activated during puberty. Mariano Marcos State University College of Health Sciences 19 Department of Nursing  CN 100 ANATOMY & PHYSIOLOGY: CHAPTER 3 INTEGUMENTARY SYSTEM C. NAILS  Thin plate consisting of layers of stratum corneum that contain a very hard type of keratin  Cells form a clear, solid covering over the dorsal surfaces of the distal portions of the digits  Grows continuously and does not have a resting stage  Consists of: a. NAIL BODY – portion of the nail that is visible b. FREE EDGE – part that may extend past the distal end of the digit c. NAIL ROOT – buried in a fold of skin d. LUNULA – whitish crescent-shaped area of the proximal end of the nail body e. HYPONICHIUM – secures the nail to the finger tip f. EPONYCHIUM – or cuticle; narrow band of epidermis that extends from and adheres to the margins of the nail wall. g. NAIL MATRIX – deep to nail root; cells which divide mitotically to produce growth Figure 7. Nails Photo credit: PAP © 2014. © Gerard J. Tortora, L.L.C., Bryan Derrickson, John Wiley & Sons, Inc. Mariano Marcos State University College of Health Sciences 20 Department of Nursing  CN 100 ANATOMY & PHYSIOLOGY: CHAPTER 3 INTEGUMENTARY SYSTEM  Growth rate of nails are influenced by:  person’s age,  health and  nutritional status with an average of 1mm (0.04 in) per week  Growth rate varies according to season, time of day, and environmental temperature.  Growth rate of toenails are somewhat slower D. RECEPTORS  Specialized tissues, which are extremely sensitive to certain types of stimuli:  MERKEL’S CORPUSCLE – receptors of light touch  PACINIAN – deep pressure Exteroceptors, cutaneous receptors  FREE NERVE ENDINGS – hot & cold, pain EFFECTS OF AGING ON THE INTEGUMENTARY SYSTEM: a. reduced blood flow (blood vessels walls become thickened & less permeable) b. collagen fibers decrease in number, stiffen, break apart and disorganize into shapeless, matted tangle c. elastic fibers lose some of their elasticity, thicken into clumps and fray (greatly accelerated in the skin of smokers) d. fibroblasts decrease in number  formation of crevices & furrows (wrinkles) e. SC tissue decrease f. decreased activity of sebaceous & sweat glands  dry & broken skin  increase susceptibility to infection g. decrease in # of functioning melanocytes  gray hair & atypical pigmentation (liver spots) h. decrease immune system – poor skin wound healing THE INTEGUMENTARY SYSTEM AS A DIAGNOSTIC AID  Useful in diagnosis because it is easily observed and often reflects conditions of other body systems. 1. Cyanosis – bluish discoloration of the skin 2. Jaundice – yellowish color 3. Rashes and lesions 4. Changes in accessory structure RELATED CONDITIONS BURN  Injury to the skin due to excessive exposure to heat, electricity, chemical, radiation or gases  Graded according to their severity/depth of burn: Mariano Marcos State University College of Health Sciences 21 Department of Nursing  CN 100 ANATOMY & PHYSIOLOGY: CHAPTER 3 INTEGUMENTARY SYSTEM 1. PARTIAL THICKNESS BURN – portion of stratum basale remains variable & regeneration is possible within the burn area & edges of the wound  first degree = epidermis; red & painful with slight edema  second degree = epidermis & dermis; healing depends on extent of dermal involvement; red, painful with edema & blisters Figure 6. Burns Photo credit: PAP © 2014. © Gerard J. Tortora, L.L.C., Bryan Derrickson, John Wiley & Sons, Inc. 2. FULL THCKNESS BURN – third-degree burn; epidermis & dermis are completely destroyed; painless  when large areas of the skin are severely burned, systemic effects can occur which can be life-threatening CANCER (SKIN) 1. Basal Cell Carcinoma – most frequent; 78% of all skin cancers; tumors arise from cells in the s. bassale of the epidermis and rarely metastasize Mariano Marcos State University College of Health Sciences 22 Department of Nursing  CN 100 ANATOMY & PHYSIOLOGY: CHAPTER 3 INTEGUMENTARY SYSTEM 2. Squamous Cell Carcinoma – 20% of all skin cancers; arise from squamous cells of the epidermis and have a variable tendency to metastasize. 3. Malignant Melanoma – rare form; 2% of all skin cancers; most prevalent nife- threatening cancer in young women; metastasize rapidly and can kill a person within months of diagnosis CLINICAL DISORDERS OF THE INTEGUMENTARY SYSTEM 1. Impetigo  caused by staphylococcus aureus; characterized by small blisters containing pus that easily rupture and forms a yellowish crust 2. Acne  disorder of hair follicles and sebaceous glands 3. Decubitus Ulcers/ Bed Sores/ Pressure Sores  necrosis of the skin due to tissue compression & reduced circulation 4. Bullae  fluid-filled areas in the skin that develop when tissues are damaged 5. Psoriasis  caused by increased mitosis in stratum basale, abnormal keratinizaiton and elongation of dermal papillae toward the skin surface producing thicker-than- normal skin 6. Eczema & Dermatitis  inflammatory conditions of the skin 7. Ringworm  fungal infection affecting the keratinized portion of the skin, hair and nails 8. Viral Infections –  e.g. chicken pox, measles, warts 9. Birthmarks  congenital disorder of the capillary of the dermis 10. Vitiligo  development of patches of white skin SKIN WOUND HEALING 2 TYPES: (depending on the depth of injury) 1. EPIDERMAL WOUND HEALING  The edges of the wound involve only slight damage to superficial epidermal cells.  Common types include: abrasions and minor burns  PROCESS: In response to an epidermal injury, basal cells of the epidermis surrounding the wound break contact with the basement membrane. The cells then enlarge and migrate across the wound. The cells appear to migrate as a sheet until Mariano Marcos State University College of Health Sciences 23 Department of Nursing  CN 100 ANATOMY & PHYSIOLOGY: CHAPTER 3 INTEGUMENTARY SYSTEM advancing cells from opposite sides of the wound meet. When epidermal cells encounter one another, they stop migrating due to a cellular response called contact inhibition. Migration of the epidermal cells stops completely when each is finally in contact with other epidermal cells on all sides. As the basal epidermal cells migrate, a hormone called epidermal growth factor stimulates basal stem cells to divide and replace the ones that have moved into the wound. The relocated basal epidermal cells divide to build new strata, thus thickening the new epidermis Figure 7. Epidermal Wound Healing Photo credit: PAP © 2014. © Gerard J. Tortora, L.L.C., Bryan Derrickson, John Wiley & Sons, Inc. 2. DEEP WOUND HEALING  Occurs when injury extends to the dermis and subcutaneous layer.  Healing process is more complex than epidermal wound healing.  Presence of Scar Tissue Formation  Healed tissue loses some of its normal function.  FOUR PHASES: 1. INFLAMMATORY PHASE  BLOOD CLOT FORMS IN THE WOUND LOOSELY UNITING THE WOUND EDGES  INFLAMMATION OCCURS (a vascular & cellular response that help eliminates microbes, foreign materials and dying tissue in preparation for repair) 2. MIGRATORY PHASE  CLOT BECOMES SCAB & EPITHELIAL CELLS MIGRATE BENEATH THE SCAB BRIDGING THE WOUND  Fibroblast migrate along fibrin threads and begin synthesizing Scar Tissue (collagen fibers & glycoproteins) Mariano Marcos State University College of Health Sciences 24 Department of Nursing  CN 100 ANATOMY & PHYSIOLOGY: CHAPTER 3 INTEGUMENTARY SYSTEM  Damaged blood vessels begin to grow  GRANULATION TISSUE = tissue filling the wound 3. PROLIFERATIVE PHASE  Characterized by extensive growth of epithelial cells beneath the scab  Deposition by fibroblasts of collagen fibers in random patterns occur  Continued growth of blood vessels 4. MATURATION PHASE  Scab sloughs off once the epidermis has been restored to normal thickness  Collagen fibers become more organized  Blood vessels restored to normal Figure 8. Deep Wound Healing Photo credit: PAP © 2014. © Gerard J. Tortora, L.L.C., Bryan Derrickson, John Wiley & Sons, Inc.  The process of scar tissue formation = FIBROSIS  HYPERTROPHIC SCAR – scar remains within the boundaries of the original wound  KELOID SCARS – scars that extends beyond the boundaries of the original wound into normal surrounding tissues Mariano Marcos State University College of Health Sciences 25 Department of Nursing  CN 100 ANATOMY & PHYSIOLOGY: CHAPTER 3 INTEGUMENTARY SYSTEM ACTIVITY 3. Test your knowledge! Are you ready? Let’s get going! You will find the Answer Key at the end of the lesson. 1. In response to stimuli from the sympathetic nervous system, the arrector pili ________. a. are glands in the skin surface b. can lead to excessive sweating c. are responsible for goose bumps d. secrete sebum 2. Similar to the hair, nails grow continuously throughout our lives. Which of the following is furthest from the nail growth center? a. nail bed b. hyponichum c. nail root d. eponychium 3. Sebaceous glands ________. a. are a type of sweat gland b. are associated with hair follicle c. may function in relation to touch d. release a watery solution of salt and metabolic waste 4. Eccrine sweat glands ________. a. act as a moisturizer b. are present in the skin throughout the body and produce watery sweat c. are present on hair d. produce sebum 5. The hair matrix contains ___________. a. the hair follicle b. the hair shaft c. the glassy membrane d. a layer of basal cells WRAP-UP ACTIVITY RECALL: Accessory structures of the skin include hair, nails, sweat glands, and sebaceous glands. These structures embryologically originate from the epidermis and can extend down through the dermis into the hypodermis. Mariano Marcos State University College of Health Sciences 26 Department of Nursing  CN 100 ANATOMY & PHYSIOLOGY: CHAPTER 3 INTEGUMENTARY SYSTEM CONGRATULATIONS! You made it! You were great! You are done with the Chapter 3. After finishing the learning pocket material, you have acquired the basic knowledge on functions of the integumentary systems, the structure of the skin and the accessory skin structures. Review your lessons in preparation for your quiz, which will be scheduled and administered online by your Instructor. There are also websites listed in your syllabus that you can visit to help enhance your learning in Anatomy and Physiology. Keep it up! FEEDBACK Answer Key: Lesson 2 Lesson 3 Lesson 1 Warm up activity Activity 2 Warm up Activity 1. c 1. d 1. b 2. a 2. a 2. d 3. b 3. c 3. d 4. b Activity Activity 1 5. c 1. c What did you learn? 2. b 1. The synthesis of vitamin D3 is important in regulating 3. b the levels of calcium and phosphate in the blood. 4. b 2. Sweating cools the body when it becomes warm. When 5. d the body temperature rises, such as when exercising on a hot day, the dermal blood vessels dilate, and the sweat glands begin to secrete more sweat. The evaporation of the sweat from the surface of the skin cools the body by dissipating heat. 3. When the core body temperature drops, the body switches to heat-conservation mode. This can include an inhibition to excessive sweating and a decrease of blood flow to the papillary layers of the skin. This reduction of blood flow helps conserves body heat. What do you think? 1. The children were not getting enough vitamin D in their diet, and they were spending all of their daylight hours indoors. Since the children weren’t exposed to much sunlight, their skin could not synthesize vitamin D from the UV rays of the sun. Without adequate amounts of vitamin D, the children succumbed to rickets. How did it go with your practice test? Are you satisfied with your score? Do you need further study? Do you have more questions about the topics? How do you find the it, did it help you with your learning? Feel free to contact your Instructor at his/her given consultation time for the course. Mariano Marcos State University College of Health Sciences 27 Department of Nursing  CN 100 ANATOMY & PHYSIOLOGY: CHAPTER 3 INTEGUMENTARY SYSTEM REFERENCE MATERIALS  Tortora, Gerard/ Derrickson Bryan 2013. Principles of Anatomy and Physiology 14th edition  Marieb, Elaine. 2014 Essentials of Human Anatomy and Physiology11th edition. Philippines: Pearson Education South Asia.  Seeley, Rod R. et al. 2011. Essentials of Anatomy and Physiology 11th edition. New York: McGraw-Hill.  Bergman, R. A. (n.d.). Anatomy Atlases. Retrieved from Anatomy Atlases website: http://www.anatomyatlases.org  Visible Body. (n.d.). Retrieved from visiblebody.com: http://www.visiblebody.com Mariano Marcos State University College of Health Sciences 28 Department of Nursing