Unit 3 (Chapter 5) - The Integumentary System and Body Membranes Presented by Dawn Duran, PT, MHS,CSCS Adjunct Professor, Kaplan University

Types of Membranes Epithelial membranes - Epithelial membranes are composed of epithelial tissue and an underlying layer of specialized connective tissue called the basement membrane. Cutaneous membranes Mucous membranes Serous membranes Pleura Pericardium Peritoneum Connective Tissue Membranes Synovial tissue membranes

CLASSIFICATION OF BODY MEMBRANES Epithelial membranes The cutaneous membrane refers to the skin, which is the primary organ of the integumentary system. It is the largest organ of the body Composes ~15% of total body weight in most individuals.

CLASSIFICATION OF BODY MEMBRANES Mucous membranes line body cavities that open up to the outside, such as the digestive tract. The linings of the respiratory, reproductive, and urinary tracts are examples of mucous membranes. Other examples: eyes, nose, mouth vagina, anus Produce mucus, a thick secretion that keeps the membranes soft and moist Another purpose of mucus is to catch debris, and not allow it to enter the body. It helps to keep out invading pathogens.

CLASSIFICATION OF BODY MEMBRANES Serous Membranes Line the cavities that do not open to the outside world Examples include the heart, kidneys, spleen, and lungs. Composed of two distinct layers of tissue Epithelial sheet is a thin layer of simple squamous epithelium Connective tissue layer forms a thin, gluelike basement membrane that holds and supports epithelial cells In other words, serous membranes are double membranes. They may become inflamed due to infection.

CLASSIFICATION OF BODY MEMBRANES Double layered – the serous membrane is a single, continuous sheet that covers two different surfaces Visceral membrane covers the surface of organs found in body cavities A serous membrane that covers the organs found in a body cavity is referred to as the visceral portion. Parietal membrane lines body cavities A serous membrane that lines the walls of a body cavity is referred to as the parietal portion. Serous fluid is in the cavity between them This fluid prevents friction when movement occurs Friction would create a build-up of heat

Serous Membranes Pleura = A serous membrane lining the walls of the thoracic cavity and covering the lungs. The parietal layer of the pleura adheres to the wall of the chest and the visceral layer is attached to the lung. With every breath we take the two layers slide past each other with little friction, making it easier for us to breathe. Peritoneum = serous membrane lining the walls of the abdominal cavity and covering the organs in that cavity.

Synovial Membranes Synovial membranes are connective tissue membranes They do not contain epithelial components They line the spaces between bones and joints that move as well as the lining of bursa sacs that are found between many moving body parts Produce a lubricant called synovial fluid Synovial membranes and synovial fluid help to reduce friction

Disorders of Body Membranes Diseases Pleurisy—inflammation of the serous membranes that line the chest cavity and cover the lungs Pain is caused by irritation and friction as the lungs rub against the walls of the chest cavity Peritonitis—inflammation of the serous membranes in the abdominal cavity that line the walls and cover the abdominal organs A possible complication of appendicitis is inflammation of the serous membrane that lines the abdominal cavity is and is termed peritonitis.

Integumentary System Integument = covering The Integumentary system consists of: Skin Accessory Organs: Hair Nails Glands The skin is the largest organ of the body

What are the functions of the skin? QUESTION: What are the functions of the skin?

Functions of the Skin Protection from injuries Acts as a barrier and regulates what enters/leaves body. Regulates body temperature. Synthesizes and stores vitamin D Sensory functions/sense organ activity

Temperature Regulation The skin helps with controlling our body temperature by regulating sweat secretion and by regulating the flow of blood close to the body surface. Blood vessels to the skin constrict when the body needs to conserve heat.

Functions of the Skin Sense organ activity Skin functions as an enormous sense organ Receptors serve as receivers for the body, keeping it informed of changes in its environment We have specialized receptors for light touch, pressure, pain, heat and cold.

Functions of the Skin Protection—first line of defense Against infection by microbes Against fluid loss Keratin is a tough waterproof protein that gives the outer layer of the skin some protection and helps to prevent dehydration. Against ultraviolet rays from sun Melanin is responsible for absorbing harmful ultraviolet radiation from the sun before it reaches the deeper tissues of the integumentary system. Against harmful chemicals Against cuts and tears

Structures of the Skin 3 main layers from superficial to deep: Epidermis Dermis Subcutaneous/ Hypodermis

Structures of the Skin 1) Epidermis Epi- derm/o -is above skin structure “structure above the skin” a. The outermost and primary layer of the skin. b. The stratum corneum is the tough outer/superficial layer of the epidermis. This layer contains keratin. c. The innermost layer of the epidermis that that has cells that continually reproduce with new cells moving toward the surface stratum germinativum. d. The epidermis is avascular.

Structures of the Skin 2) Dermis Derm/o -is Skin structure “true skin” a. thick, connective tissue layer with collagen and elastic fibers, epithelial tissue, smooth muscle tissue, nervous tissue and blood b. The dermis lies directly above the subcutaneous layer. c. The dermis is thicker than the epidermis.

Dermis The dermal papilla forms ridges and grooves that make up the fingerprints on the tips of the fingers. The purpose of skin ridges on our fingers and toes is to improve our grip when using tools or walking barefoot. Loss of elasticity due to decreased numbers of elastic fibers contributes to wrinkles and aging. The dermis contains an abundance of elastic fibers. Subcutaneous injections of medicines are meant to reach the hypodermis.

Sensory Structures of Dermis Receptors of the integumentary system are found in the dermis. Deep touch/pressure on the skin surface/vibration: Pacinian corpuscles Light touch/pressure: Meisner’s corpuscles Warm temperature: Free nerve endings Cold temperature: Free nerve endings Pain: Free nerve endings

Structure of the Skin, cont. 3) Subcutaneous tissue/Hypodermis Sub- cutane/o -us Below skin structure “structure below the skin” a. The hypodermis consists of adipose tissue which provides insulation from extremes of heat and cold as well as a source of stored energy. It can be used as a food source in some situations. It also provides a cushion of protection from injury.

You should be able to label this diagram, found on p 103.

What are some of the accessory structures of the skin? QUESTION: What are some of the accessory structures of the skin?

ANSWER: Hair Nails (produced by the epidermis) Specialized Sense Organs (found in the dermis) Glands The skin itself is the main organ of the integumentary system. The integumentary system also INCLUDES the skin, hair and specialized sense organs.

Accessory Structures of the skin Hair The fine, soft hair of fetus and newborn called lanugo Hair growth requires epidermal tube-like structure called hair follicle (Fig 5.5, p 107) Hair growth begins in the papilla when cells of the epidermal layer grown down into the dermis, forming a small tube called a hair follicle Hair root lies hidden in follicle; visible part of the hair is called the shaft Alopecia is the term for hair loss Arrector pili - specialized smooth muscle that produces “goose bumps” and causes hair to stand up straight when we become frightened or cold

Accessory Structures of the skin Nails (Figure 5-6, p 108) Produced by epidermal cells over terminal ends of fingers and toes Visible part called nail body Root lies in a groove and is hidden by cuticle Crescent-shaped area nearest root called lunula Nail bed may change color with change in blood flow as it is abundant in blood vessels

Accessory Structures of the skin Skin glands Types Sweat or sudoriferous (apocrine and eccrine) Sebaceous

Accessory Structures of the skin Sweat or sudoriferous glands Types Eccrine sweat gland Most numerous, important, and widespread of the sweat glands. There are more sweat glands than oil glands in one square inch of skin. Produce perspiration or sweat, which flows out through pores on skin surface. When this evaporates, the body loses heat. Function throughout life and assist in body heat regulation as well as elimination of waste products such as ammonia and uric acid

Accessory Structures of the skin Apocrine sweat gland Found primarily in axilla and around genitalia Secrete a thicker, milky secretion quite different from eccrine perspiration Breakdown of secretion by skin bacteria produces odor These glands enlarge and begin to function at puberty

Accessory Structures of the skin Sebaceous gland Secrete oil/sebum to lubricate hair and skin Level of secretion increases during adolescence Amount of secretion regulated by sex hormones Sebum accunulation in sebaceous gland ducts forms white pimples, and sebum often darkens when exposed to air, forming a blackhead Acne vulgaris is the term for inflammation of sebaceous gland ducts

Dermis Sweat gland Sebaceous gland Arrector pili muscle Blood vessels

The Skin Appendages of the skin Receptors Receptors are specialized nerve endings that make it possible for the skin to act as a sense organ Meissner’s corpuscle—capable of detecting light touch; located close to the skin surface Pacinian corpuscle—capable of detecting pressure

Quick Quiz Ok, quick quiz. Which layer of the skin does not have a blood supply?

ANSWER Correct! The epidermis doesn’t have a blood supply. The epidermis and subcutaneous tissues do have a blood supply.

Quick Quiz Which layer has the pigment cells?

ANSWER The epidermis again. Remember that it has many layers. The pigment cells begin development in the dermis and migrate to the epidermis as they mature.

Quick Quiz What is that pigment called?

ANSWER Melanin! It is produced by the melanocytes. This pigment is called melanin and is responsible for giving the skin some of its color. Dark skinned individuals can get melanoma despite the fact that the dark skinned individuals have more melanocytes than fair skinned individuals.

Quick Quiz Which layer has the fatty tissue?

ANSWER The subcutaneous tissue/hypodermis.

Burns The severity of a burn is determined by the depth of the injury as well as by the amount of surface area involved. First-degree (partial-thickness) burns - only the surface layers of epidermis involved. Causes minor discomfort and some skin reddening, but no blistering and minimal damage. Example: typical sunburn. Second-degree (partial-thickness) burns - involve the deep epidermal layers and always cause injury to the upper layers of the dermis. Causes blisters, reddening of the skin, severe pain, swelling and fluid loss. Scarring is also common. Third-degree (full-thickness) burns — characterized by complete destruction of the epidermis and dermis and tissue death extends into subcutaneous tissues. Often involve muscles and bone. Not painful because nerve endings are destroyed. This is the most serious type of burn. The most serious complications of third degree burns is fluid loss and risk of infection.

Burns All of the following can cause burns to the skin: Electricity Ultraviolet light Chemicals

Burns Determining the extent of burn injury is possible by utilizing the “rule of nines” in adults; this estimates the body surface area effected by the burn. The body is divided into 11 areas of 9% each Additional 1% of body surface area around genitals

The Rule of Nines **Be able to use the Rule of Nines to answer a question regarding %age of body burned based on a scenario provided on your exam**

Skin Cancer Three common types Squamous cell carcinoma—is common; lesions begin as hard, painless nodules; it will metastasize. Metastasis is when cancer spreads to distant sites from where it originated. Basal cell carcinoma— the most common type of skin cancer. Melanoma— the most serious type of skin cancer. Is indicated by a pigmented spot that contains different colors.

Warning Signs of Malignancy The "ABCD" rule of self-examination of moles refers to the warning signs of melanoma. Assymetry – benign moles are normally symmetrical, whereas malignancies are not Border – benign moles have a distinct border, whereas malignancies are indistinct or irregular Color – benign moles are brown and even colored whereas malignancies are unevenly colored and often have a mix shades and colors Diameter – malignancies tend to be larger than ¼ inch in diameter

Skin Cancer The most important causative factor in common skin cancers is exposure to sunlight. In other words, ultraviolet radiation is the most important factor in causing skin cancer. UV radiation damages the DNA in skin cells which interferes with normal mitosis and leads to cancer.

Decubitus Ulcers Decubitus ulcers (aka bedsores/pressure sores) develop when excessive pressure slows down blood flow to sensitive areas More common in bedridden or immobilized individuals However, they are NOT always a sign of abuse.

Miscellaneous Cyanosis is when the skin or mucous membranes turn blue because of too little oxygen to the tissues.

Let’s Review!

Which type of body membrane lines the digestive tract? Cutaneous membrane Tympanic membrane Serous membrane Synovial membrane Mucous membrane

ANSWER Answer: E Mucous membrane lines cavities that are open to the exterior, which includes the lumen of the digestive tract.

The skin plays important roles in maintaining a stable body temperature. True False

ANSWER Answer: A How? Via sweating and diversion of blood flow.

What is the largest sensory organ of the body? Eye Ear Tongue Skin Nose

ANSWER Answer: D All the sensory receptors in the largest organ of the body make skin the clear winner.

What characterizes second-degree burns? A. blisters B. swelling C. severe pain D.all of the above

ANSWER Answer: D

That’s All, Folks! See you on the DB!