Human Anatomy & Physiology: Tissues Chapter 2 PDF

Chapter 2 Tissues Fundamentals of Anatomy and Physiology  Tissues are groups of cells with similar structure and function. Histology is study of tissues. Tissue types: Epithelial, Connective, Muscle, and Nervous Epithelial Tissue  Epith...

Chapter 2 Tissues Fundamentals of Anatomy and Physiology  Tissues are groups of cells with similar structure and function. Histology is study of tissues. Tissue types: Epithelial, Connective, Muscle, and Nervous Epithelial Tissue  Epithelial Tissue Functions 1. Protects underlying tissues 2. Absorbs nutrients 3. Secretes hormones, mucus, and enzymes 4. Excretes waste  Epithelial Tissue Characteristics 1. Cells fit closely together and often form sheets 2. Avascular (no blood supply) 3. Regenerate easily if well nourished  Epithelial Tissue Basement membrane: anchor Named according to shape, arrangement, function Cells are closely packed  Classification Based on Shape 1. Squamous: flat (protection) 2. Cuboidal: cube shaped (protection and secretion) 3. Columnar: tall and rectangular (secretion and absorption).. Squamous Cuboidal Columnar Classification based on cell shape. Classification Based on Shape. Classification Based on Shape. Classification Based on Shape  Classification Based on Arrangement 1. Simple: one cell layer 2. Stratified: several layers 3. Pseudostratified: appears to be several layers but is not 4. Transitional: several layers of easily stretched cells. Classification Based on Arrangement  Simple Epithelial Tissue Simple Squamous o Single layer of flat cells o Location—usually forms membranes ▪ Lines air sacs of the lungs ▪ Forms walls of capillaries ▪ Forms serous membranes (serosae) that line and cover organs in ventral cavity o Functions in diffusion, filtration, or secretion in membranes Simple Epithelial Tissue Simple Epithelial Tissue Simple Epithelial Tissue  Simple Epithelial Tissue Simple Cuboidal o Single layer of cube-like cells o Locations: ▪ Common in glands and their ducts ▪ Forms walls of kidney tubules ▪ Covers the surface of ovaries o Functions in secretion and absorption; ciliated types propel mucus or reproductive cells Simple Epithelial Tissue Simple Epithelial Tissue Simple Epithelial Tissue  Simple Epithelial Tissue Simple Columnar o Single layer of tall cells ▪ Goblet cells secrete mucus o Location: ▪ Lines digestive tract from stomach to anus ▪ Mucous membranes (mucosae) line body cavities ▪ It lines the uterus, stomach, and intestines where it protects underlying tissues, secretes digestive fluids, and absorbs nutrients. o Functions in secretion and absorption; ciliated types propel mucus or reproductive cells Simple Epithelial Tissue Simple Epithelial Tissue Simple Epithelial Tissue  Pseudostratified Epithelial Tissue Pseudostratified Columnar o All cells rest on a basement membrane o Single layer, but some cells are shorter than others giving a false (pseudo) impression of stratification o Location: ▪ Respiratory tract, where it is ciliated and known as pseudostratified ciliated columnar epithelium o Functions in absorption or secretion Pseudostratified Epithelial Tissue Pseudostratified Epithelial Tissue Pseudostratified Epithelial Tissue Pseudostratified ciliated, columnar epithelium  Stratified Epithelial Tissue Stratified Squamous o Named for cells present at the free (apical) surface, which are flattened o Functions as a protective covering where friction is common o Locations—lining of the: ▪ Skin (outer portion) ▪ Mouth ▪ Esophagus Stratified Epithelial Tissue Stratified Epithelial Tissue  Stratified Epithelial Tissue Stratified cuboidal o Two layers of cuboidal cells; functions in protection Stratified columnar o Surface cells are columnar, and cells underneath vary in size and shape; functions in protection *Stratified cuboidal and columnar o Rare in human body o Found mainly in ducts of large glands Stratified Epithelial Tissue Stratified Cuboidal Epithelium Stratified Epithelial Tissue Stratified Columnar Epithelium  Transitional Epithelial Tissue Transitional Epithelium o Composed of modified stratified squamous epithelium o Shape of cells depends upon the amount of stretching o Functions in stretching and the ability to return to normal shape o Locations: urinary system organs Transitional Epithelial Tissue Transitional Epithelial Tissue Transitional Epithelial Tissue Transitional epithelium  Classification Based on Function 1. Mucous membrane: mucus production 2. Exocrine glands: discharge their products through ducts. 3. Endocrine: hormone secretion 4. Endothelium: lines vessels Endocardium 5. Mesothelium (serous): lines great cavities  Mucous Membranes Lines the digestive, respiratory, urinary, and reproductive tracts. Usually ciliated. Produce mucus, concentrates bile, secretes enzymes for digestion, protects, and absorb nutrients.  Exocrine Glands Secretions empty through ducts to the epithelial surface Include sweat and oil glands, liver, and pancreas Includes both internal and external glands  Endocrine Glands Ductless; secretions diffuse into blood vessels. All secretions are hormones. Examples include thyroid, adrenals, and pituitary.  Endothelium Epithelium that lines the circulatory and lymphatic system. Simple squamous Ex.: Endocardium  Mesothelium AKA – serous tissue Lines the cavities that have no openings to the outside. Simple squamous Ex.: Pleura, Pericardium, Peritoneum Connective Tissue  Connective Tissue Cells with large amount of intercellular material Found everywhere in the body Includes the most abundant and widely distributed tissues Subgroups: Loose, Dense, and Specialized  Connective Tissue Characteristics Variations in blood supply o Some tissue types are well vascularized o Some have a poor blood supply or are avascular Extracellular matrix o Nonliving material that surrounds living cells  Connective Tissue Characteristics Extracellular Matrix Two main elements 1. Ground substance—mostly water along with adhesion proteins and polysaccharide molecules 2. Fibers o Produced by the cells o Three types: ▪ Collagen (white) fibers ▪ Elastic (yellow) fibers ▪ Reticular fibers (a type of collagen)  Loose Connective Tissue Fills space between and penetrates organs Areolar o Most widely distributed connective tissue o Functions as a universal packing tissue and “glue” to hold organs in place o All fiber types form a loose network o Forms the delicate membrane around the skin and the spinal cord. Loose Connective Tissue  Loose Connective Tissue Areolar Fibroblasts o Small, flattened cells with large nuclei and reduced cytoplasm. o Irregular in shape. o Have the ability to form fibrils. o Active in the repair of injury.  Loose Connective Tissue Areolar Histiocytes o Large, stationary phagocytic cells o Eat up debris and microorganisms outside the blood circulatory system Mast Cells o Roundish or polygonal in shape o Found close to blood vessels o For production of heparin and histamine. Loose Connective Tissue  Loose Connective Tissue Adipose o Matrix is an areolar tissue in which fat globules predominate o Many cells contain large lipid deposits with nucleus to one side o Functions: ▪ Insulates the body ▪ Protects some organs ▪ Serves as a site of fuel storage. Loose Connective Tissue  Loose Connective Tissue Reticular Connective Tissue o Delicate network of interwoven fibers with reticular cells (like fibroblasts) o Locations: ▪ Forms the internal framework of organs, such as these lymphoid organs: ▪ Lymph nodes ▪ Spleen ▪ Bone marrow. Loose Connective Tissue  Dense Connective Tissue Composed of tightly packed protein fibers. *Arrangement of fibers (regular) o Tendons—attach skeletal muscle to bone o Ligaments—attach bone to bone at joints and are more elastic than tendons o Aponeuroses—wide flat tendons  Dense Connective Tissue *Arrangement of fibers (irregular) o Muscle sheaths o Dermis o Outer covering of body tubes like arteries o Fascia – muscle covering. Dense Connective Tissue. Dense Connective Tissue  Specialized Connective Tissue Cartilage o Less hard and more flexible than bone o Found in only a few places in the body o Cells called chondrocytes - Found in lacunae o Types ▪ Hyaline ▪ Fibrocartilage ▪ Elastic  Specialized Connective Tissue Hyaline Cartilage The most widespread type of cartilage o Composed of abundant collagen fibers and a rubbery matrix with no visible fibers o Locations: ▪ Septum of nose ▪ Entire fetal skeleton prior to birth ▪ Trachea and bronchi ▪ Surfaces of bones and joints ▪ Costal cartilages o Functions as a more flexible skeletal element than bone. Specialized Connective Tissue. Specialized Connective Tissue Fibrocartilage Highly compressible Location: Forms cushion like discs between vertebrae of the spinal column  Specialized Connective Tissue Elastic Cartilage Provides elasticity Location: Supports the external ear, epiglottis, larynx  Specialized Connective Tissue Bone (osseous tissue) Compact bone – dense outer layer Cancellous bone – inner spongy-looking tissue Composed of: o Osteocytes (bone cells) sitting in lacunae (cavities) o Hard matrix of calcium and phosphorous salts o Large numbers of collagen fibers Functions to protect and support the body. Specialized Connective Tissue. Specialized Connective Tissue  Specialized Connective Tissue Teeth o Dentin ▪ Material that forms our teeth ▪ Harder and denser than bone ▪ Light brown o Enamel ▪ Covers the crown of the tooth ▪ White  Specialized Connective Tissue Blood (vascular tissue) Blood cells surrounded by fluid matrix known as blood plasma Soluble fibers are visible only during clotting Functions as the transport vehicle for the cardiovascular system, carrying: ▪ Nutrients ▪ Wastes ▪ Respiratory gases. Specialized Connective Tissue  Specialized Connective Tissue Lymphoid Tissue Found in lymph glands and nodes, thymus, spleen, tonsils, and the adenoids. Antibody production  Specialized Connective Tissue Reticuloendothelial or RE System Do phagocytosis Kupffer's Cells – line the liver, spleen, and bone marrow. Macrophages – “resting-wandering” and devouring Neuroglia and Microglia – found in the CNS Synovial Membranes Line the cavities of freely moving joints Prevent friction  Connective Tissue Functions Support Movement o Bones, Cartilage o Bones, Tendons Nourishment Protection and insulation o Blood o Bones, Blood, Fat Transportation Storage o Blood o Bone, Fat Connection Attachment and separation o Tendons, Ligaments o Attaches skin to muscle Muscle Tissue  Muscle Tissue Function is to contract, or shorten, to produce movement Three types: o Smooth muscle o Striated/Skeletal muscle o Cardiac muscle  Muscle Tissue Smooth (visceral) muscle o Involuntarily controlled o Found in walls of hollow organs such as stomach, uterus, and blood vessels o Peristalsis, a wavelike activity, is a typical activity o Characteristics of smooth muscle cells ▪ No visible striations ▪ Uninucleate ▪ Spindle-shaped cells. Muscle Tissue  Muscle Tissue Skeletal muscle o Voluntarily (consciously) controlled o Attached to the skeleton and pull on bones or skin o Produces gross body movements or facial expressions o Characteristics of skeletal muscle cells ▪ Striations (stripes) ▪ Multinucleated (more than one nucleus) ▪ Long, cylindrical shape. Muscle Tissue  Muscle Tissue Cardiac muscle o Involuntarily controlled o Found only in the heart o Pumps blood through blood vessels o Characteristics of cardiac muscle cells ▪ Striations ▪ Uninucleate, short, branching cells ▪ Intercalated discs contain gap junctions to connect cells together. Cardiac Muscle Nervous Tissue  Nervous Tissue Makes up the brain, spinal cord, and various nerves in the body Neurons o Conducting cells o Very long: called nerve fibers o Parts ▪ Cell body: contains nucleus ▪ Dendrites: rootlike extensions that receive stimuli ▪ Axons: long thin extensions that transmit impulse  Nervous Tissue o Neuroglia: supporting cells o Nervous tissue functions: ▪ Makes up brain, spinal cord, and nerves ▪ Is most highly organized tissue of the body ▪ Controls and coordinates body activities ▪ Allows perception ▪ Controls emotion and reasoning ▪ Stores memories. Nervous Tissue Motor Neuron. Nervous Tissue  Thank You! Do you have any questions for me before we go?