[Week 4 Part 2] MT13 LAB - CHAPTER 4 - Integumentary System [DCC-LLENOS].pdf

CHAPTER IV THE INTEGUMENTARY SYSTEM DANIEL CHARLES C. LLENOS, RMT Institute of Clinical Laboratory Sciences Silliman University MT 13 – ANATOMY AND PHYSIOLOGY THE INTEGUMENTARY SYSTEM ▪ The skin is also known as the cutaneous membrane. ▪ The cutaneous me...

CHAPTER IV THE INTEGUMENTARY SYSTEM DANIEL CHARLES C. LLENOS, RMT Institute of Clinical Laboratory Sciences Silliman University MT 13 – ANATOMY AND PHYSIOLOGY THE INTEGUMENTARY SYSTEM ▪ The skin is also known as the cutaneous membrane. ▪ The cutaneous membrane is part of two major body membranes: epithelial and connective tissue membrane. ▪ The Skin and its appendages (sweat and oil glands, hair, and nails) are collectively called the integumentary system. MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 2 MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 3 MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 4 MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 5 MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 6 STRUCTURE OF THE SKIN Divided into layers: 1. Epidermis (Outer) – made up of stratified squamous epithelium 2. Dermis (inner/underlying layer) – made up mostly of dense irregular connective tissue. 3. Hypodermis (subcutaneous tissue) – not part of the skin, just a layer of adipose tissue. Anchor the skin to the underlying organs and provides a site for nutrient storage. MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 7 MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 8 MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 9 EPIDERMIS An avascular layer of keratinized stratified squamous epithelium consisting of four distinct cell types and four/five distinct layers. Cells of the Epidermis: ▪ Keratinocytes that produce keratin. Most abundant cell type. o Keratin is a fibrous protein that makes the epidermis a tough protective layer through a process of keratinization ▪ Merkel Cells (aka Tactile Epithelial Cells). In combination with sensory nerve endings, form sensitive touch receptors (Merkel Discs) located at the epidermal-dermal junction. MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 10 EPIDERMIS Cells of the Epidermis ▪ Melanocytes are cells that produce the brown-to-black pigment known as Melanin o Melanin production increases when skin is exposed to UV o Melanin provides a protective pigment umbrella over the nuclei of the cells (shield the DNA) o Freckles and moles (nevi) are areas where melanin is more concentrated. ▪ Dendritic Cells (Langerhans Cells). From the bone marrow and migrate to the epidermis. They ingest foreign substances and play a key role in activating the immune response. MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 11 MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 12 EPIDERMIS Layers of the Epidermis ▪ In Thin skin, the epidermis consists of only four layers which covers most of the body. ▪ In Thick skin, found on the palms of the hands and sole of the feet, contain an additional layer. MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 13 MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 14 MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 15 MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 16 MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 17 DERMIS ▪ A strong, stretchy envelope that helps to bind the body together ▪ Both collagen and elastic fibers are found throughout the dermis ▪ Varying thickness ▪ Example: thick on the palms of the hands, thin on the eyelids Two Major Regions i.) Papillary Dermis ii.) Reticular Dermis MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 18 DERMIS: TWO MAJOR REGIONS PAPILLARY DERMIS is the superficial dermal region. Composed of Areolar connective tissue. ▪ Very uneven and has fingerlike projections from its superior surface (dermal papillae). ▪ The dermal papillae lie on top of the larger dermal ridges. ▪ These ridges have sweat pores and leave unique, identifying films of sweat – fingerprint. ▪ Abundant capillary networks are present in this layer and allow heat to radiate to the skin surface. ▪ Pain receptors (free nerve endings) and touch receptors (tactile corpuscles) are also found here. MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 19 MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 20 DERMIS: TWO MAJOR REGIONS The Reticular Dermis is the deepest skin layer. ▪ It is composed of dense irregular connective tissue ▪ Contains many arteries and veins ▪ Also contains the sweat and sebaceous glands ▪ Pressure receptors (lamellar corpuscles) are also present MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 21 MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 22 MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 23 ACCESSORY ORGANS OF THE SKIN ▪ Include: Nails, hair, and cutaneous glands. ▪ Are derivates of the epidermis but reside primarily in the dermis. ▪ Originate from the Stratum Basale and extend into the dermis. ▪ They are also known as the Appendages of the skin. MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 24 NAILS Scalelike modification of the epidermis that corresponds to the hoof or claw of other animals. MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 25 MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 26 HAIR AND ASSOCIATED STRUCTURES ▪ Hair (enclosed in hair follicles) are found all over the entire body surface. ▪ Exceptions: thick-skinned areas (palms of hands, soles of feet), parts of the external genitalia, the nipples, and the lips. Two Primary Regions of the Hair: 1.) Hair Shaft – the region projecting from the surface of the skin 2.) Hair Root – beneath the surface of the skin and is embedded within the hair follicle. ▪ Hair Bulb – collection of well-nourished epithelial cells at the base of the hair follicle. Deepest part of the follicle. MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 27 HAIR AND ASSOCIATED STRUCTURES Both regions have three layers of keratinized cells: ▪ Medulla – in the center. consists of large cells and air spaces. ▪ Cortex – surrounds the medulla. contains melanin pigment that determines hair color. ▪ Cuticle – outermost layer. Single layer of cells that overlap with one another. o This arrangement of the cuticle helps to keep the hairs apart and keeps them from matting. o Most heavily keratinized region. o Abrasion of the cuticle at the tip of the hair shaft results in split ends. MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 28 MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 29 MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 30 ASSOCIATED STRUCTURES OF THE HAIR a.) Hair Follicle – a structure formed from epidermal and dermal cells. ▪ Its epithelial root sheath, with two parts (internal and external) is enclosed by a thickened basement membrane (glassy membrane) and by a peripheral connective tissue sheath (dermal tissue). ▪ The dermal tissue provides nutrients to the epithelial tissue. The epithelial tissue forms the hair. ▪ Hair Papilla – a small nipple of dermal tissue that protrudes into the hair bulb from the peripheral connective tissue sheath and provides nutrition to the growing hair. ▪ Hair matrix – located on top of the hair papilla, a layer of actively dividing epithelial cells. Stratum Basale (growth zone). MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 31 ASSOCIATED STRUCTURES OF THE HAIR b.) Arrector Pili Muscle – small bands of smooth muscle cells connect each hair follicle to the papillary layer of the dermis. ▪ When these muscles contract (during cold or fright), the slanted hair follicle is pulled upright, dimpling the skin surface with goose bumps. MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 32 MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 33 MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 34 MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 35 MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 36 CUTANEOUS GLANDS ▪ ALL are exocrine glands that release their secretions to the skin surface via ducts. ▪ These glands are formed by cells of the stratum basale, but are pushed deeper into the skin and reside almost entirely in the dermis. ▪ Includes: Sebaceous Glands and Sweat Glands MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 37 CUTANEOUS GLANDS SEBACEOUS (OIL) GLANDS ▪ Found nearly all over the skin, except the palms of the hands and the soles of the feet. ▪ Sebum is the product of sebaceous glands. o Mixture of oily substances and fragmented cells o Acts as a lubricant to keep skin soft and moist o Prevents the hair from becoming brittle o Also has chemicals that kill bacteria ▪ Active during puberty, when more male hormones (androgens) begin to be produced for both genders MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 38 MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 39 CUTANEOUS GLANDS SEBACEOUS (OIL) GLANDS ▪ When sebaceous glands ducts are blocked by sebum, acne appears. o Acne is an active infection of the sebaceous glands o Blackhead forms when the accumulated material oxidizes and dries and darkens o Whitehead forms when the material does not dry or darken ▪ Seborrhea (“fast-flowing sebum”), known as “cradle cap” in infants is caused by overactivity of the sebaceous glands. MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 40 MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 41 MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 42 CUTANEOUS GLANDS SWEAT (SUDORIFEROUS) GLANDS ▪ Widely distributed all over the skin. ▪ Outlets for the glands are pores (epithelial opening). ▪ They are categorized by the composition of their secretions. ▪ Includes: Eccrine and Apocrine Sweat glands MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 43 CUTANEOUS GLANDS ECCRINE (“MEROCRINE”) SWEAT GLANDS ▪ Produce a clear secretion (“sweat”) consisting primarily of: ✓ Water, ✓ Salts (mostly NaCl), ✓ Vit. C ✓ Metabolic waste (urea, ammonia, uric acid) ▪ Sweat is acidic (pH of 4 to 6) which inhibit the growth of microbes ▪ Important in the body’s heat-regulating apparatus ▪ Secrete sweat when the external temperature or body temperature is high ▪ When sweat evaporates, it carries excess body heat with it. ▪ These glands are distributed all over the body. MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 44 MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 45 CUTANEOUS GLANDS APOCRINE SWEAT GLANDS ▪ Found predominantly in the axillary and genital areas. ▪ The sweat of this gland is an excellent nutrient medium for microbes typically found in the skin. ▪ Apocrine sweat is eccrine sweat + Proteins and Fat-rich substances ▪ Apocrine sweat is initially odorless, but when bacteria breaks down its organic components, it begins to smell unpleasant. ▪ Activated by nerve fibers during pain and stress and during sexual arousal. ▪ Function not entirely known. MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 46 MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 47 MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 48 HOMEOSTATIC IMBALANCE: SKIN ULCERS ▪ Any restriction of the normal blood supply to the skin results in cell death and if, severe or prolonged enough, skin ulcers. ▪ Decubitus ulcers (bedsores) occur in bedridden patients who are not turned regularly or who are dragged or pulled across the bed repeatedly. ▪ Weight of the body puts pressure on the skin. ▪ This pressure restricts the blood supply → the skin becomes pale or blanched at pressure points. ▪ If not corrected, there can be permanent damage to the superficial blood vessels and tissue that eventually results in degeneration and ulceration of the skin. MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 49 MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 50 HOMEOSTATIC IMBALANCE: CYANOSIS ▪ When blood is inadequately oxygenated, as during asphyxiation and serious lung disease, both the blood and the skin take on a bluish cast. MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 51 HOMEOSTATIC IMBALANCE: JAUNDICE ▪ Jaundice in which the skin becomes yellow due to liver disease. MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 52 HOMEOSTATIC IMBALANCE: ADDISON’S DISEASE ▪ Prominent Feature: Bronzing of the skin ▪ Cause: Hypoactive Adrenal Cortex MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 53 HOMEOSTATIC IMBALANCE: INFECTIONS AND ALLERGIES i.) Athletes Foot – infection with fungus Tinea pedis; itchy red peeling condition of skin between the toes ii.) Boils (furuncles) – inflammation of hair follicles and surrounding tissue (commonly on dorsal neck) iii.) Carbuncles – are clusters of boils often caused by Staphylococcus aureus iv.) Cold Sores (fever blisters) – fluid filled blisters that itch and sting. Caused by Human Herpesvirus 1 (HHV-1) infection. Usually around the lips and mucosa of the mouth and nose. MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 54 HOMEOSTATIC IMBALANCE: INFECTIONS AND ALLERGIES iv.) Contact dermatitis – itching, redness, swelling of skin progressing to blistering. Caused by exposure to chemicals (poison ivy) that provoke an allergic response. v.) Impetigo – pink, fluid-filled, raised lesions (mouth and nose) that develop a yellow crust and rupture and weep fluid. Caused by Staphylococcus or streptococcus infections. Common in elementary school children. vi.) Psoriasis is characterized by reddened epidermal lesions covered with dry, silvery scales that itch, burn, crack, and sometimes bleed. Chronic condition. Believed to be autoimmune. MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 55 ATHLETE’S FOOT MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 56 MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 57 CONTACT DERMATITIS (FROM POISON IVY) MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 58 References ▪ Marieb E.N & Jackson P.B. (2018). Essentials of Human Anatomy and Physiology Laboratory Manual, Seventh Edition. Singapore: Pearson Education South Asia Pte Ltd. ▪ Marieb E.N & Keller S.M. (2022). Essentials of Human Anatomy and Physiology, Thirteenth Edition. England, United Kingdom: Pearson Education Limited. ▪ Marieb E.N & Smith L.A. (2019). Human Anatomy & Physiology Laboratory Manual, Thirteenth Edition. United States of America: Pearson Education Inc. ▪ Tortora G.J. & Derrickson B. (2009). Principles of Anatomy and Physiology, Twelfth Edition. New Jersey, U.S: John Wiley & Sons, Inc. MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 59 End of Discussion For inquiries: [email protected] MT 13 ANATOMY AND PHYSIOLOGY I DCC-LLENOS 60