CLS 224 Lecture 3: The Integumentary System & Body Membranes PDF

CLS 224 (Basic Anatomy & Physiology) Lecture 3: The Integumentary System & Body Membranes Contents: Part I: Body Membranes 1. Functions 2. Classification of Body Membranes Part II: The Integumentary System (Skin) 1. Functi...

CLS 224 (Basic Anatomy & Physiology) Lecture 3: The Integumentary System & Body Membranes Contents: Part I: Body Membranes 1. Functions 2. Classification of Body Membranes Part II: The Integumentary System (Skin) 1. Functions of the Skin 2. Structure of the Skin 3. Appendages of the Skin Part I: Body Membranes  Part I: Body Membranes Objectives: List the general functions of each membrane type and give its location in the body. Compare the structure (tissue makeup) of the major membrane types. Part I: Body Membranes Function of body membranes:  cover body surfaces  Protect body surfaces  Line body cavities  Lubricate body surfaces Part I: Body Membranes Classification of Body Membranes: A. Epithelial membranes 1. Cutaneous membrane 2. Mucous membrane 3. Serous membrane B. Connective tissue membranes  synovial membranes Part I: Body Membranes Classification of Body Membranes A.Epithelial membranes: calling these membranes “epithelial” is not only misleading but also inaccurate !!!!!!! these membranes are actually simple organs. Part I: Body Membranes Classification of Body Membranes: 1. Cutaneous Membrane:  Cutaneous membrane = skin  A dry membrane  Outermost protective boundary a. Superficial epidermis  Keratinized stratified squamous epithelium b. Underlying dermis  Mostly dense (fibrous) connective tissue Part I: Body Membranes Classification of Body Membranes: 1. Cutaneous Membrane: Keratinized stratified squamous epithelium skin Part I: Body Membranes Classification of Body Membranes: 2. Mucous membrane (mucosa):  Surface : epithelium  Type depends on site  Underlying loose connective tissue (lamina propria)  Lines all body cavities that open to the exterior body surface  “wet,” or moist membranes  Often adapted for absorption or secretion not all do secrete mucus Part I: Body Membranes Classification of Body Membranes: 3. Serous membrane (serosa):  Surface simple squamous epithelium  Underlying areolar connective tissue Part I: Body Membranes Classification of Body Membranes: 3. Serous membrane (serosa):  Lines open body cavities that are closed to the exterior of the body (except for the dorsal body cavity and joint cavities) Part I: Body Membranes Classification of Body Membranes: 3. Serous membrane (serosa): occur in pairs The parietal (parie = wall) layer lines a specific portion of the wall of the ventral body Cavity.  It folds in on itself to form the visceral layer, which covers the outside of the organs in that cavity.  Serous layers separated by serous fluid Part I: Body Membranes Classification of Body Membranes: 3. Serous membrane (serosa): Part I: Body Membranes Classification of Body Membranes: 3. Serous membrane (serosa): Specific serous membranes a. Peritoneum  Abdominal cavity b. Pleura  Around the lungs c. Pericardium  Around the heart Part I: Body Membranes Classification of Body Membranes: B. Connective tissue membranes: Synovial membrane  Connective tissue (soft areolar) only  Lines fibrous capsules surrounding joints  provide a smooth surface and secrete a lubricating fluid Part I: Body Membranes Classification of Body Membranes: B. Connective tissue membranes: Synovial membrane  cushion organs moving against each other during  They also line small sacs of muscle activity—such as connective tissue called the movement of a tendon bursae and the tube-like across a bone’s surface. tendon sheaths. Part I: Body Membranes Classification of Body Membranes: B. Connective tissue membranes: Synovial membrane Part II: The Integumentary System (Skin)  Part II: The Integumentary System (Skin) Part II: The Integumentary System Objectives: List several important functions of the integumentary system, and explain how these functions are accomplished. When provided with a model or diagram of the skin, recognize and name the following skin structures: epidermis, dermis (papillary and reticular layers), hair and hair follicle, sebaceous gland, and sweat gland. Name the layers of the epidermis, and describe the characteristics of each. Part II: The Integumentary System integument = “covering” A. Skin (cutaneous membrane). B. Skin derivatives: 1. Hairs 2. Nails 3. multicellular exocrine glands:  Sweat glands  Oil glands Part II: The Integumentary System A. Skin  Structure: A. Epidermis – outer layer  Stratified squamous epithelium  Often keratinized (hardened by keratin) B. Dermis – Inner layer  Mostly dense connective tissues The epidermis and dermis are firmly connected but can get separated by friction (ex: blister). Part II: The Integumentary System A. Skin  Structure: Deep to dermis is the  provides a site for fat storage. hypodermis/ the subcutaneous tissue:  It serves as a shock  Not part of the skin absorber and insolates the deeper tissues from  Anchors skin to extreme temperature underlying organs changes outside the  Composed mostly of body. adipose tissue Part II: The Integumentary System A. Skin  Structure  Layer of Epidermis: 1. Stratum basale / stratum germinativum  Cells undergoing mitosis  Lies next to dermis 2. Stratum spinosum 3. Stratum granulosum 4. Stratum lucidum  Occurs only in thick skin 5. Stratum corneum  Shingle-like dead cells  20 to 30 cell layers thick Part II: The Integumentary System A. Skin  Structure A. Epidermis:  Avascular (no blood supply of its own) stratified squamous epithelium.  Nutrients and oxygen diffuse from capillaries in the dermis  Cells of the epiderm is: Keratinocytes: contain large amounts of keratin (fibrous protein) the most abundant cells in the epidermis. Part II: The Integumentary System A. Skin  Structure A. Epidermis: melanin:  Pigment (melanin) produced by melanocytes  Color is yellow to brown to black  Melanocytes are mostly in the stratum basale  Amount of melanin produced depends upon genetic and exposure to sunlight Part II: The Integumentary System A. Skin  Structure A. Epidermis: Part II: The Integumentary System A. Skin  Structure A. Epidermis: Part II: The Integumentary System A. Skin  Structure B. Dermis:  Two layers 1. Papillary layer  Projections called dermal papillae  Pain receptors  Capillary loops 2. Reticular layer contains irregularly arranged connective tissue fibers  Blood vessels  Glands (sweat and oil glands)  Nerve receptors (deep pressure, lamellar corpuscles) Part II: The Integumentary System A. Skin  Structure: B. Dermis: Part II: The Integumentary System A. Skin:  functions: Part II: The Integumentary System B. Skin derivatives/Appendages 1. Sebaceous glands:  Produce sebum=oily substances and fragmented cells  Lubricant for skin  Kills bacteria  Most with ducts that empty into hair follicles  Glands are activated at puberty  found all over the skin, except on the palms of the hands and the soles of the feet Part II: The Integumentary System B. Skin derivatives/Appendages: 2. Sweat glands / sudoriferous (sudor = sweat) glands :  Widely distributed in skin  Two types a. Eccrine b. Apocrine: the axillary (armpit) and genital areas secretion contains fatty acids and proteins, as well as all the substances present in eccrine Part II: The Integumentary System B. Skin derivatives/Appendages: 2. Sweat glands / sudoriferous (sudor = sweat) glands : sweat, a clear secretion that is primarily water plus some salts (sodium chloride), vitamin C, traces of metabolic wastes (ammonia, urea, uric acid), and lactic acid (a chemical that accumulates during vigorous muscle activity).  Function: Sweat is acidic  Helps dissipate excess heat (pH from 4 to 6)  Excretes waste products  Acidic nature inhibits bacteria growth  Odor is from associated bacteria Part II: The Integumentary System B. Skin derivatives/Appendages: Nail: protect fingers and toes: –made of dead cells packed with keratin –metabolic disorders can change nail structure –Lack of pigment makes them colorless. Part II: The Integumentary System B. Skin derivatives/Appendages: Hair:  Produced by hair bulb  Melanocytes provide pigment for hair color  Consists of hard keratinized epithelial cells References: 1- 2- Principles of Anatomy and Physiology 15th edition Ebook PDF e Text Book by Gerard J. Tortora & Bryan derrickson, 2017.