Tissues PDF

TISSUES  Learning Competency 1. Classify the different animal tissues and specify the function/s of each. a. define and describe a tissue; b. characterize and classify the types of epithelial tissue, connective tissue, muscle tissue, and ne...

TISSUES  Learning Competency 1. Classify the different animal tissues and specify the function/s of each. a. define and describe a tissue; b. characterize and classify the types of epithelial tissue, connective tissue, muscle tissue, and nervous tissue; and c. appreciate the functions of the different tissues. How the human body is organized?  Tissues and Histology Tissues are collections of similar cells and the extracellular matrix surrounding them group of cells closely associated that have similar structures and perform a related function Histology is the study of tissues The 4 Primary Types of Tissue: 1. Epithelial tissue 2. Connective tissue 3. Muscle tissue 4. Nervous tissue Classification of Animal Tissues Animal Tissues Epithelial Connective Muscle Nervous DVD/MVC copy 6 Tissues of the body DVD/MVC copy 7 Tissues of the body DVD/MVC copy 8  4 Types of Tissues 1) Epithelial Tissue Covers surfaces Has little extracellular material Usually has a basement membrane Has no blood vessels  Functions of Epithelial Tissue 1. Protecting underlying structures – Example: outer layer of skin and oral mucosa 2. Acting as barriers – Example: outer layer of skin 3. Permitting the passage of substances – Example: epithelium in the lungs 4. Secreting substances – Example: mucous glands and sweat glands 5. Absorbing substances – Example: epithelial cells of the intestine Epithelial Tissue Characteristics ▪ cells are packed together ▪ cells are arranged in layers or sheets ▪ avascular ▪ nutrition – diffusion or osmosis Classification ▪ based on shape ▪ based on arrangement ▪ based on functions Epithelial Tissue: Based on Arrangement 1. Squamous 2. Cuboidal 3. Columnar Epithelial Tissue: Based on Arrangement 1. Simple 2. Stratified 3. Pseudostratified 4. Transitional  Stratified epithelium 1. Stratified squamous 2. Stratified cuboidal 3. Stratified columnar 4. Transitional epithelium  Classifications of Epithelial Tissue A. Number of Cell layers 1. Simple epithelium has one layer of cells 2. Stratified epithelium has more than one cell layer 3. Pseudostratified epithelium has one layer, but appears to have two or more layers 4. Transitional epithelium is stratified epithelium that can be greatly stretched B. Cell shape 1. Squamous are flat and thin 2. Cuboidal are cubelike 3. Columnar are tall and thin Functions of Epithelial Tissue 1. Protection ▪ epithelium of the epidermis, epithelium of the lining of the digestive tract 2. Absorption ▪ epithelium of the small intestine 3. Secretion ▪ all glands are made up of epithelial tissue 4. Excretion ▪ sweat glands excrete waste products such as urea Epithelial Tissue: Based on Function 1. Mucous membrane – secretes mucous, enzymes and bile salts, absorbs nutrients and protects 2. Glandular epithelium – forms glands 3. Endothelium – lines the blood vessels and the lymphatic vessels 4. Mesothelium (serous membrane) – lines the great cavities of the body that have no openings to the outside DVD/MVC copy 23  Epithelial Tissue Glands A gland is a single cell or a multicellular structure that secretes substances onto a surface, into a cavity, or into the blood. 1. Endocrine glands do not have ducts Secrete hormones directly into the blood 2. Exocrine glands have ducts Secretions are released onto a surface or into a cavity – Sweat glands and mammary glands  Epithelial Tissue Glands Structure of Exocrine Glands a) Simple: have one duct b) Compound: have ducts that branch repeatedly c) Tubules: ducts end in small tubes d) Acini: ducts end in saclike structures e) Alveoli: ducts end in hollow sacs  DVD/MVC copy Epithelial Tissue Glands Exocrine Glands and Secretion Types 1. Merocrine – no loss of cellular material (Ex. sweat glands) 2. Apocrine – part of the cell pinches off (Ex. mammary glands) 3. Holocrine – entire cell is shed (Ex. sebaceous glands) 28  4 Types of Tissues 2) Connective Tissue consist of cells separated from each other by abundant extracellular matrix Functions: 1. Enclosing and separating 2. Connecting tissues to one another (Ex. Ligaments & Tendons) 3. Supporting and moving (Ex. Bones and cartilage) 4. Storing (Ex. Adipose tissue and Bones) 5. Cushioning and insulating (Ex. Adipose tissue) 6. Transporting (Ex. Blood) 7. Protecting (Ex. Blood and Bones) Functions of Connective Tissue 1. Support – bones, muscle, nerves, blood vessels, fat, skin, cartilage 2. Nourishment – blood, synovial membranes 3. Transportation – blood 4. Connection – tendons, ligaments 5. Movement – muscles, bones 6. Protection – bones, blood cells 7. Insulation – adipose tissues 8. Storage – bone, adipose tissues 9. Attachment and Separation – CT attaches skin to underlying muscle  4 Types of Tissues 2) Connective Tissue Extracellular matrix contains: 1. Protein fibers Collagen fibers are flexible but resist stretching Reticular fibers form a fiber network Elastic fibers recoil 2. Ground substance Proteoglycans in ground substance hold water, enabling connective tissues to return to their original shape after being compressed 3. Fluid Connective Tissue Characteristics ▪ matrix with collagen and elastin ▪ vascularized ▪ allows movement and provides support for other types of tissue Classification ▪ Loose Connective Tissue (LCT) ▪ Dense Connective Tissue (DCT) ▪ Specialized Connective Tissue (SCT)  Classifications of Connective Tissue 1. Loose, or areolar, connective tissue is the “loose packing” material of the body Fills the spaces between organs Holds organs in place 2. Adipose tissue (fat) Stores energy Pads and protects parts of the body Acts as a thermal insulator 3. Dense connective tissue consists of a matrix containing densely packed fibers Collagen fibers (Ex. tendons, ligaments, and dermis of the skin) Elastic fibers (Ex. elastic ligaments and in the walls of arteries) Loose Connective Tissue (LCT) fibers are not tightly woven basic support tissue around organs, muscles, blood vessels, and nerves forms the delicate membranes around the spinal cord and brain attaches skin to underlying tissue 1. Areolar Tissue – fibroblasts, histiocytes, mast cells 2. Adipose Tissue – fat cells 3. Reticular Tissue – liver, spleen, lymph nodes, bone marrow Dense Connective Tissue (LCT) tightly packed protein fibers 1. Regular – fibers run in the same directions (tendons, ligaments, aponeuroses) 2. Irregular – fibers run in different directions (fasciae, muscle sheets, dermis, outer coverings of body tubes like arteries, fibrous capsules at ends of bones) DVD/MVC copy 39 Specialized Connective Tissue (SCT) with specialized functions 1. Cartilage – provides firm but flexible support for the embryonic skeleton and part of the adult skeleton A. Hyaline cartilage – embryonic skeleton, costal cartilages that attach the ribs to the sternum, septum of nose, rings of trachea and bronchi B. Fibrocartilage – collagen fibers (intervertebral disk, pubic symphysis) C. Elastic cartilage – elastic fibers (auditory ear tube, external ear, epiglottis, and larynx) Specialized Connective Tissue (SCT) (cont.) 2. Bone Tissue – osteocytes are embedded in the matrix of calcium and phosphate 3. Dentin – forms the teeth and secretes enamel 4. Blood and Hematopoietic tissues A. corpuscles – formed in red bone marrow B. WBCs – formed in lymphoid organs 5. Lymphoid tissue – manufactures plasma cells 6. Reticuloendothelial System – phagocytosis in CT 7. Synovial membranes – joints and bursae, produces synovial fluid  Classifications of Connective Tissue Matrix with both protein fibers & ground substances 1) Cartilage provides support A. Hyaline cartilage (Ex. covers ends of bones and forms costal cartilages) B. Fibrocartilage (Ex. disks between vertebrae) C. Elastic cartilage (Ex. external ear)  Classifications of Connective Tissue 2) Bone has a mineralized matrix forms most of the skeleton of the body A. Compact bone has more matrix than spaces B. Cancellous bone has more spaces than matrix 3) Blood has a liquid matrix Found in blood vessels Produced in hemopoietic tissue (red bone marrow) 51 Muscle Tissue Characteristics long, elongated, slender cells called muscle fibers sarcolemma – membrane covering of a muscle fiber muscle fiber – myofibrils (myosin and actin) Classification ▪ Smooth ▪ Skeletal / Striated ▪ Cardiac Muscle Tissues (cont.) Differences of Muscle Tissues Smooth Skeletal Cardiac Shape of Fiber fusiform elongated / filamentous net-like No. of Nuclei uninucleated multinucleated synctial Position of Nuclei central peripheral central Cross Striations absent present present Speed of Contraction slowest most rapid intermediate Type of Nervous involuntary voluntary involuntary Control Location walls of digestive, movable parts of the walls of the heart genitourinary, respiratory skeleton tract, blood vessels and lymphatic vessels Functions of Muscle Tissue 1. Smooth muscle ▪ involuntary movements (digestive tract, controls diameter of blood vessels and pupil of the eyes) 2. Striated or skeletal muscle ▪ capable of rapid, powerful contractions and long states of partially sustained contractions 3. Cardiac muscle ▪ heart contraction Nervous Tissue Characteristics ▪ makes up the brain, spinal cord, and various nerves ▪ neurons – “nerve fibers” (cell body, axon, dendrites) ▪ most highly organized tissue Functions ▪ controls and coordinates body activities ▪ respond to stimuli – irritability and conductivity