CHAPTER 4: The Tissue Level of Organization Tissue= a group of similar cells that work together to perform a particular function Histology= the study of tissues Pathologist= doctor who studies cells and tissues for changes that might indicate disease There are 4 major tissue types 1. Epithelial tissue (epithelium) a. covers body surfaces b. lines hollow organs, body cavities and ducts c. specialized epithelial tissue forms glands 2. Connective tissue a.Protects and supports the body and its organs b.Binds organs together c.Stores energy reserve as fat d.Provides immunity against disease causing organisms 3. Muscle tissue a.Generates movement b.Generates body heat 4. Nerve tissue a.Detects changes inside and outside of the body b.Initiates and transmits nerve impulses that help maintain homeostasis Epithelial Tissue Strongly connected to adjacent cells by junctions Tight seals Apical side=adjacent to exterior or to a body cavity. Basal side= opposite area Classified by cell shape number of cell layers apical layer Simple=one layer of cells Stratified=more than one layer Copyright 2010, John Wiley & Sons, Inc. Epithelial Tissues All epithelia are directional: they have an apical [outer] surface and basal and lateral surfaces All epithelia are avascular, and depend upon diffusion for nutrients What does avascular indicate about these tissues? Epithelia fit into two categories: Covering and lining epithelia Glandular epithelium Copyright 2010, John Wiley & Sons, Inc. Epithelial Tissues 3 Basic Shapes Squamous=flat scale-like Cuboidal=cube shaped Columnar=column shaped Epithelial Cell Characteristics Bio.Davidson.edu Avascular Do not contain capillaries Sensory Endings of neurons are present within epithelial cell tissues Perceive external stimulus (i.e. tactile) Gliding surface layer Slough off and glide in order to replace dead cells Maintain a closed barrier to the external environment Transitional Multiple layers stretch Urinary bladder distends or contracts without damage Tight barrier Tightly secured together Resilient to mechanical stress Different from endothelial cells Endothelial cells line the insides of structures that arent exposed to the outside Ex. Blood vessels Epithelial Types 1.Simple squamous=single layer flattened shaped Location: lining of heart and blood vessels, external lining of visceral organs Function: a. diffusion of material through epithelial layer b. blood filtration in kidney Copyright 2010, John Wiley & Sons, Inc. Epithelial Tissue: Simple Squamous Epithelium 2. Simple cuboidal= single layer of square or round cells. Nucleus in middle Contain microvilli in apical layer Location: liver, pancreas, thyroid, salivary glands, kidney tubules, bronchioles Function: Absorption in kidney and liver Secretion in kidney, liver, pancreas, thyroid, and glands Copyright 2010, John Wiley & Sons, Inc. Epithelial Tissue: Simple Cuboidal Epithelium 3. Simple columnar= single layer of tall narrow cells, oval or cylindrical shaped. Nucleus at basal side Location=inner lining of stomach, intestines, uterus, uterine tubes Function: absorption of nutrients in intestine movement of egg and embryo in uterine tube secretion of mucus to lubricate intestine Copyright 2010, John Wiley & Sons, Inc. Epithelial Tissue: Simple Columnar Epithelium (Nonciliated) 4. Stratified squamous= multiple cell layers with cells becoming flatter toward the surface Keratinized layer= Dead cells Unnucleated What is Keratin? Location: Keratinized = epidermis, palms, soles of feet Non-keratinized = surface of tongue, lining of esophagus and birthing canal General Functions: Protection Protects against water loss, pathogen entry consumption and swallowing of food, child birth Copyright 2010, John Wiley & Sons, Inc. Epithelial Tissue: Stratified Squamous Epithelium Copyright 2010, John Wiley & Sons, Inc. Epithelial Tissue: Ciliated Simple Columnar Epithelium 5. Stratified cuboidal = 2 or more layers of cells. Surface layers are square or round Location: sweat gland ducts, ovarian follicle cells Function: contribute to sweat secretion secretion of ovarian hormones 6. Stratified columnar= 2 or more layers, tall and narrow with basally located nuclei Location: pharynx, male urethra, ducts of sweat and salivary glands Function: structural integrity of gland ducts 7. Pseudostratified columnar= A single layer of cells Cells are a variety of heights Nuclei at different layers Have cilia Location: respiratory tract from nasal cavity to bronchi Function: secrete mucus in resp tract which traps dust and bacteria cilia sweeps mucus towards pharynx to be swallowed Copyright 2010, John Wiley & Sons, Inc. Epithelial Tissue: Pseudostratified Columnar Epithelium 8. Transitional epithelium= Surface cells range from squamous when stretched to cuboidal when relaxed. Location: lines urinary tract, kidney, bladder, urethra Function: stretches to allow filling of bladder Copyright 2010, John Wiley & Sons, Inc. Epithelial Tissue: Transitional Epithelium Glands Gland= cell or an organ that secretes substances inside or outside the body. Composed of epithelial tissue Classified as exocrine or endocrine Exocrine= secrete their products into ducts that empty on the skin surface or the lumen of a hollow organ ex. Sweat glands, salivary glands Endocrine= products(hormones) are secreted directly into the blood ex. Pituitary, adrenal, thyroid Connective Tissue What is connective tissue? Connects, supports, binds, or separates other tissues or organs, typically having relatively few cells embedded in an amorphous matrix Most abundant tissue of the body. What functions do different types of CT perform? Work with a partner! Record your answers. Connective Tissue Cells widely separated by lots of extracellular material Most abundant tissue of the body adipose, cartilage, bone, tendons, and blood. Functions: 1.Binds together, supports and strengthens other tissues of the body 2.Protects and insulates internal organs 3.Compartmentalizes structures such as skeletal muscles 4.Transport system 5.Major site of stored energy reserve 6.Main source of immune response Connective Tissue Where do these functions occur in the body? Provide an example for each one. Functions: 1.Patellar Tendon Binds, supports, and strengthens other tissues 2.Visceral Fat Protects and insulates internal organs 3.Biceps Muscle Compartmentalizes structures such as skeletal muscles 4.Blood is Fluid CT Transport system 5.White and Brown Adipose Tissue Major site of stored energy reserve 6.White blood cells Main source of immune response A&P EXTENSION The Patellar tendon attaches the bottom of the kneecap (patella) to the top of the shinbone (tibia). A&P EXTENSION Tendons connect the biceps to bone. Provides direction from a fixed point for muscle to gain leverage for extension and contraction. General Features of CT Highly vascular What are the exceptions? Cartilage and Tendons Composed of 2 basic elements 1.Cells which are separated by 2. Matrix - (this is the extracellular material) a.Ground substance- secreted by CT cells. b.Protein fibers- secreted by CT cells CT Cells Immature cells 1. name ending in blast ex Osteoblast 2. capable of cell division 3. Secrete extracellular matrix that is characteristic to its tissue Mature cells 1.Name ending in cyte ex. Osteocyte 2.Reduced capacity for cell division 3.A bone cell which maintains the matrix and structure of bone Cells found in CTs Fibroblasts- secrete fibers and ground substance Macrophages-engulf bacteria and cellular debris by phagocytosis Plasma cells-secrete antibodies, proteins that attack or neutralize foreign substances Adipocytes- fat cells that store triglycerides White blood cells- involved in immune response Cells found in CTs Mast cells- produce histamine which dilates small blood vessels as part of the inflammatory response, the bodys reaction to injury or infection. Produce heparin which is a natural anticoagulant. Prevents inappropriate clotting of vesselsbody/14063-body-invaders-allergies-and-dust-mites- video.htmbody/14063-body-invaders-allergies-and-dust-mites- video.htm CT Extracellular Matrix Ground Substance- between cells and fibers Material found in ground substance 1. water 2. Hyaluronic acid- slippery, binds cells together, lubricates joints and maintains shape of eyeball IMPORTANT Component of Cartilage https://www.youtube.com/watch?v=0IUAmz1R4zk CT Extracellular Matrix Fibers Three types of fibers in matrix 1.collagen-tough and resistant to pulling. Found in bone, cartilage, tendons and ligaments. White appearance 2.Elastic- smaller than collagen. Branch and stretch. Contain protein elastin. Allow lungs arteries and skin to spring back after they are stretched. Yellow appearance 3.Reticular-thinner collagen fiber. Support in blood vessels, spleen and lymph nodes EXIT PASS Osteoblasts and Osteocytes https://www.youtube.com/watch?v=xXgZap0 AvL0 https://www.youtube.com/watch?v=xXgZap0 AvL0 Describe the formation of intramembranous bone. Types of CT Embryonic embryo to 3 months of pregnancy 2 TYPES 1. Mesenchyme produces all other CTs Differentiate into bone cartilage blood 2. Mucous ct found in the umbilical cord Mature There are 5 types of mature CT 1.Loose-fibers are loosely woven many cells a. areolar-surounds blood vessels, nerves, trachea esophagus function: provide strength, elasticity, support b. Adipose-beneath skin, breast, heart surface, eyes, kidneys fucntion: insulator-prevents heat loss through skin, cushions some organs c. reticular-lymph nodes, spleen,thymus, bone marrow function: framework for lymphatic organs 2. Dense more fibers with fewer cells a. dense regular-parallel wavy fibers. Tendons and ligaments function: Compare a tendon with a ligament Tendons attach muscle to bone Ligaments attach bone to bone b. dense irregular- fibers run in random directions function:strength c. elastic-elastic fibers give tissue yellowish color. Found in lung, arteries, vocal cords, respiratory passages function: elasticity and strength 3. Cartilage- What is it composed of? dense network of collagen and elastic fibers. 3 types of cartilage a. hyaline=appears bluish white. weakest location: fetal skin, rings around trachea, nose fucntion: joint movements, support airways b. fibrocartilage=strongest location: pubic symphysis, vertebral discs, knee joint function: absorb shock in joints c. elastic-mesh location: external ear, epiglottis function: maintains shape Hyaline cartilage fibrocartilageelastic cartilage 4. Bone- stores calcium and phosphorus, contains red bone marrow which produces RBCs. Contains yellow bone marrow which stores triglycerides. spongy bone= arranged in a lattice Cancellous Bone Bone marrow Growth Plates compact bone= arranged in concentric rings Cortical Bone Outer hardened surfaces 5. Liquid CT- liquid cellular matrix 2 types A. Blood = has a plasma matrix RBCs transport O2 to cells and remove CO2 WBCs immunity, phagocytosis and allergic reactions Platelets= clotting B. Lymph= In lymphatic vessels circulates body fluid transports lipids helps defend body against pathogens Structure of the Knee https://www.youtube.com/watch?v=RTV5Yo3 E7VQ https://www.youtube.com/watch?v=RTV5Yo3 E7VQ https://www.youtube.com/watch?v=q96M0jR qn7k https://www.youtube.com/watch?v=q96M0jR qn7k Virtual Knee ReplacementDo you have what it takes to be a surgeon? Copyright 2010, John Wiley & Sons, Inc. Loose Connective Tissue: Adipose Tissue Copyright 2010, John Wiley & Sons, Inc. Loose Connective Tissue: Reticular Tissue Copyright 2010, John Wiley & Sons, Inc. Dense Connective Tissue: Dense Regular Connective Tissue Copyright 2010, John Wiley & Sons, Inc. Dense Connective Tissue: Dense Irregular Connective Tissue Copyright 2010, John Wiley & Sons, Inc. Dense Connective Tissue: Elastic Connective Tissue Copyright 2010, John Wiley & Sons, Inc. Cartilage: Hyaline Cartilage Copyright 2010, John Wiley & Sons, Inc. Cartilage: Fibrocartilage Copyright 2010, John Wiley & Sons, Inc. Cartilage: Elastic Cartilage Copyright 2010, John Wiley & Sons, Inc. Osseous Tissue: Compact Bone Copyright 2010, John Wiley & Sons, Inc. Liquid Connective Tissue: Blood Membranes Flat sheets of pliable tissue that cover or line part of the body Epithelial Membranes Combination of epithelial layer and an underlying CT layer Types 1. Mucous(mucosa) + lines the body cavity that opens directly to the exterior. +lines digestive, respiratory, reproductive and much of the urinary tracts Copyright 2010, John Wiley & Sons, Inc. Mucous Membranes (or Mucosa ) The Epithelial Layer Barrier that prevents mucous from penetrating Goblet cells secrete mucous to prevent cavities from drying out Mucous traps particles in respiratory tract and lubricates food in gastrointestinal tract Secretes enzymes for digestion The CT layer(lamina propria) Supports the epi layer and binds to the underlying structures. Allows flexibility of membrane Holds blood vessels in place, and protects underlying muscles form abrasion and punctures Diffusion of o2, nutrients, CO2 and waste 2. Serous (serosa) +lines body cavities that dont directly open to the exterior +2 layers parietal= attached to cavity wall visceral= covers and attached to the organs inside the cavity + mesothelium= secretes serous fluid- watery lubricating substance, allows organs to glide over one another or against the walls of the cavity Copyright 2010, John Wiley & Sons, Inc. Serous Membranes Examples 1. pleura= serous membrane that lines the walls of the thoracic cavity visceral pleura= covers the lungs 2. pericardium= lines the heart cavity and covers the heart 3. peritoneum= serous membrane lining the abdominal cavity and abdominal organs 3. Cutaneous Membrane (skin) covers the surface of the body Synovial Membranes Lines joint cavities and contains CT but no epi layer Place where bones come together Line cavities of freely moveable joints Secrete synovial fluid into joint cavity, which lubricates and nourishes the cartilage covering the bones and moveable joints. Contains macrophages that remove microbes and debris from the joint cavity Line cushioning sacs bursae and tendon sheaths in hands and feet easing the movement of muscles and tendons Copyright 2010, John Wiley & Sons, Inc. Cutaneous Membrane and Synovial Membrane