CHAPTER 4
Study of different tissues Abnormal cells and tissues can be compared to normal tissues to identify disease, such as cancer Being able to know and recognize normal tissues under the microscope is the first step
PRACTICE There are thousands of images, virtual labs and practice quizzes online DON T MEMORIZE Tissues from the same organ will look vastly different RECOGNIZE PATTERNS Don t get lost in the big picture, look for patterns in how cells are organized FORM = FUNCTION Keep in mind the function of the tissue and the organ
Tissue= collection of cells and cell products that perform specific, limited functions Histology = study of tissues 4 types of tissues 1. Epithelial cover and protection 2. Connective - support 3. Muscle - movement 4. Neural signaling and communication
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Covers body surfaces, lines cavities and forms glands Characteristics Cells are tightly packed together Free surface exposed to environment = APICAL SURFACE Attached to underlying connective tissue (basement membrane) Avascular (no blood supply) nutrients must diffuse Continually replaced at exposed surface
1. Protection from abrasion, dehydration, destruction 2. Regulate gas and nutrient exchange 3. Provide sensation 4. Secrete substances such as sweat, hormones, mucus and enzymes
1. First name indicates number of layers Simple: one layer of cells Stratified: more than one layer of cells Pseudostratified: appears to be stratified but is not
2. Second name describes the shape of the cells Squamous: thin and flat Cuboidal: cube shaped Columnar: tall, slender rectangles
1. Simple Squamous Description: single layer of flat cells Functions: diffusion and filtration Location: alveoli of lungs, walls of capillaries
2. Simple Cuboidal Description: single layer of cube-shaped cells Functions: secretion and absorption Locations: glands
3. Simple columnar Description: single layer, tall cells, often microvilli Function: absorption Locations: Lining of the small intestine
4. Stratified Squamous Description: many layers of flat cells (look at the shape of the cells at the apical surface) Functions: Protection from abrasion, pathogens, and chemicals Locations: skin, lining of mouth
5. Pseudostratified ciliated columnar Description: single layer of columnar cells but the position of the nuclei make it appear as there are many layers; often ciliated Functions: removing dust and particles from airways Locations: lining of respiratory tract
6. Transitional Description: transitions from one shape to the next; often has a scalloped apical edge Functions: specialized to become stretched Locations: bladder
Practice Identifying epithelial tissues Pseudostratified
Practice Identifying epithelial tissues Simple Squamous
Practice Identifying epithelial tissues Simple Cuboidal
Practice Identifying epithelial tissues Stratified Squamous
Practice Identifying epithelial tissues TRANSITIONAL
Practice Identifying epithelial tissues Simple Columnar
Most diverse tissue of the body Most abundant Not as dense as epithelial tissue Highly vascular
Composed of 1. Specialized cells Mast cells (prevent blood clots) Macrophages (phagocytic) Fibroblasts (produce the tissue) 2. Matrix (protein fibers) Collagen (thick) Elastin (thin) 3. Extracellular Components (fluid and protein)
A. Collagen fibers B. Fibroblasts C. Mast cells D. Macrophages E. Elastic fibers F. Blood vessel/cells G. Fat cells
1. Support and protection 2. Transportation of materials 3. Storage of energy reserves (fat) 4. Fights infection, repairs tissue
1. Connective Tissue Proper a) Loose Connective (areolar) b) Adipose (fat) c) Dense Connective (fibrous or collagenous) 2. Cartilage a) Hyaline b) Elastic c) Fibrocartilage 3. Other Tissues a) Bone b) Blood c) lymph
1. Loose Connective Tissue (Areolar Tissue) Structure: structural components are loosely arranged Functions: cushion, support, movement, defense against pathogens Locations: between other tissues and organs, beneath skin, digestive, respiratory and urinary tracts, between muscles, around blood vessels, nerves and joints
1. Loose Connective Tissue (Areolar Tissue)
2. Adipose (FAT) Structure: Fibroblasts enlarge and store fat, very little matrix Functions: stores energy, insulates and protects organs Locations: beneath the skin and around organs especially at sides, buttocks, breasts, around eyes and kidneys
2. Adipose Tissue
3. Dense Regular Structure: collagen fibers are parallel and are tightly packed Locations: Tendons (connect muscles to bone) and Ligaments (connect bones to bones)
3. Dense Regular
Gel-type matrix For shock absorption and protection No blood vessels Types of cartilage include Hyaline cartilage Elastic cartilage Fibrocartilage
1. Hyaline Cartilage Most common Rubbery matrix Covers ends of bones and joints and respiratory passages
2. Elastic Cartilage Elastic fibers in addition to collagen More flexible and elastic External ear
3. Fibrous Cartilage (fibrocartilage) Very tough, large numerous collagen fibers Provides strong support and handles heavy pressure Intervertebral discs
Most rigid connective tissue Rigid due to mineral salts
- Collections of cells in a fluid matrix - Blood consists of - Red blood cells transport oxygen throughout the body - White blood cells important components of the immune system - Platelets cell fragments that function in blood clotting - Plasma the watery matrix
- Lymph is formed when interstitial fluid enters the lymphatic vessels - Eventually returns to the cardiovascular system - Monitored for signs of injury or infection
Physical barriers Line internal spaces of organs and tubes that open to the outside Line body cavities Different types of membranes Mucous Serous Cutaneous Synovial
Mucous = protection Line passages that have external connections Lining of digestive, respiratory, urinary and reproductive tracts Epithelial surfaces are moist to reduce friction and help absorption and excretion
Line cavities not open to outside Are thin but strong Have fluid to reduce friction Three serous membranes Pleura lungs Peritoneum abdomen Pericardium - heart
Outer covering of body Skin Thick, waterproof and dry Stratified keratinized squamous epithelium
Line freely movable joint cavities Secrete synovial fluid into joint cavity provides lubrication Protects the end of bones Lacks a true epithelium
Specialized for contraction Produces all body movement Three types 1. Skeletal 2. Cardiac 3. Smooth
1. Skeletal Muscle Voluntary Striated multinucleate Connected to skeletal system
2. Cardiac Muscle Involuntary Striated Short branched cells connected by intercalated discs Found only in the heart
3. Smooth muscle Involuntary Non striated short Walls of hollow, contracting organs (blood vessels digestive, respiratory, urinary and reproductive tracts)
Specialized for conducting electrical impulses Rapidly senses internal or external environment Processes information and controls responses Concentrated in the central nervous system Brain and spinal cord Two kinds of neural cells Neurons = nerve cells Neuroglia = supporting cells
Tissues respond to injury to maintain homeostasis
Any type of injury affects several tissue types simultaneously and these tissues must respond in a coordinated response to restore homeostasis Two related processes 1. Inflammation 2. regeneration
The tissue s first response to injury Signs and symptoms of the inflammatory response Swelling, redness, heat, pain Can be triggered by Trauma (physical injury) or infection
1. Mast cells release chemicals to dilate blood vessels, increasing blood flow to the injury Red and warm to touch Swelling 2. Sensory nerve ending produce sensation of pain 3. Increased circulation delivers nutrients and white blood cells
1. Fibroblasts produce dense network of collagen fibers (scar tissue) 2. Most successful in epithelia, connective tissues and smooth muscle 3. Least successful in neural tissue, cardiac muscle
Speed and efficiency of tissue repair decrease with age due to Slower rate of energy consumption (metabolism) Hormonal alterations Reduced physical activity Osteoporosis age related reduction in bone density
Tissue ID quizlet