Chapter 5 ! Flashcards
What are the four broad categories of tissues?
Epithelial tissue, Connective tissue, Nervous tissue, Muscular tissue
Introduction
What is the function of epithelial tissue?
Covers body surfaces, lines body cavities, ducts, and forms glands
Introduction
What is the function of connective tissue?
Protects, supports, and binds organs. Stores energy as fat, provides immunity
Introduction
What is the function of nervous tissue?
Detect changes in the body and responds by generating nerve impulses
Introduction
What is the function of muscular tissue?
Generates the physical force needed to make body structures move and generate body heat
Introduction
What is histology?
The study of tissues and how they are arranged into organs
Introduction
What are the three primary germ layers in embryonic tissues?
Ectoderm, Endoderm, Mesoderm
Embryonic Tissues
What does the ectoderm give rise to?
Epidermis, nervous system, exocrine glands, tooth enamel, eye lens, adrenal medulla
Embryonic Tissues
What does the endoderm give rise to?
Mucous membrane lining digestive and respiratory tracts, digestive glands, among other things
Embryonic Tissues
What does the mesoderm become?
Gelatinous tissue called mesenchyme, forms all connective tissue in the body, forms epithelial lining of vessels and serous membranes
Embryonic Tissues
What are the characteristics of epithelial tissue?
Consists of a flat sheet of closely adhering cells, upper surface usually exposed, covers body surface and lines body cavities, allows no room for blood vessels, high regeneration capacity, extensive innervation
Characteristics of Epithelial Tissue
What is the basement membrane?
Layer between an epithelium and the underlying connective tissue
Characteristics Epithelial Tissue
What are the functions of epithelial tissue?
Physical protection, selective permeability, secretions, sensations
Functions of Epithelial Tissue
What are the two types of epithelial tissue?
Simple epithelium, Stratified epithelium
Classification Epithelial Tissue
What are the characteristics of simple squamous epithelium?
Single layer of flat cells, thinnest barrier, allows rapid movement of molecules, lines air sacs of lungs, vessel walls, serous membranes
Organization and Relationship of Epithelia Types
What are the characteristics of simple cuboidal epithelium?
Single layer of uniformly shaped cells, about as tall as they are wide, designed for absorption and secretion, ideal for structural components of glands
Organization and Relationship of Epithelia Types
What are the characteristics of simple columnar epithelium?
Single row of tall, narrow cells, oval nuclei in basal half of cell, brush border of microvilli, absorption and secretion, lining of GI tract, uterus, kidney, bronchioles, uterine tubes
Organization and Relationship of Epithelia Types
What are the characteristics of pseudostratified epithelium?
Looks multilayered, all cells touch basement membrane, nuclei at several layers, with cilia and goblet cells, secretes and propels mucus, respiratory tract and portions of male urethra & epididymis
Organization and Relationship of Epithelia Types
What are the characteristics of stratified epithelia?
Range from 2 to 20 or more layers of cells
Organization and Relationship of Epithelia Types
Characteristics of Stratified Epithelia
Looks multilayered; some not reaching free surface; all touch basement membrane
Types of Stratified Epithelia
Three stratified epithelia are named for the shapes of their surface cells: Stratified squamous, Stratified cuboidal, Stratified columnar (rare)
Keratinized Stratified Squamous Epithelium
Superficial layers of dead cells
Found in epidermis
Nonkeratinized Stratified Squamous Epithelium
All cells alive
Lines: Oral cavity, part of pharynx, esophagus, vagina, anus
Stratified Cuboidal Epithelium
Two or more layers of cells
Forms walls of ducts in most exocrine glands: Sweat glands, parts of male urethra, periphery of ovarian follicles
Stratified Columnar Epithelium
Rare
Found in large ducts of salivary glands, parts of male urethra
Transitional Epithelium
Limited to urinary tract; Allows for stretching as bladder fills
Binucleated cells (two nuclei)
Methods of Exocrine Gland Secretion
Merocrine secretion
E.g., sweat, lacrimal, salivary, gastric, and exocrine pancreatic glands
Connective Tissue Overview
Connective tissue—a type of tissue in which cells usually occupy less space than the extracellular material
Connective Tissue Functions
Binding of organs—tendons and ligaments
Transport—blood
Connective Tissue Cells
Fibroblasts produce fibers and ground substance
Mast cells are found alongside blood vessels
What do fibroblasts produce?
Fibroblasts produce fibers and ground substance
What do macrophages do?
Macrophages phagocytize foreign material and activate immune system when they sense foreign matter (antigen)
What type of white blood cells do monocytes arise from?
Arise from white blood cells called monocytes
What are leukocytes also known as?
Leukocytes, or white blood cells
What do neutrophils do?
Neutrophils wander about attacking bacteria
What do lymphocytes react against?
Lymphocytes react against bacteria, toxins, and other foreign material
What do plasma cells synthesize?
Plasma cells synthesize disease-fighting antibodies
What do mast cells secrete?
Mast cells are found alongside blood vessels
Secrete heparin to inhibit clotting
Secrete histamine to dilate blood vessels
What do adipocytes store?
Adipocytes store triglycerides (fat molecules)
What do mesenchymal cells do?
Mesenchymal cells divides to replace damaged cells
What type of connective tissue fibers are collagenous fibers?
Collagenous fibers
Most abundant of the body’s proteins—25%
Tough, flexible, and resist stretching
Tendons, ligaments, and deep layer of the skin are mostly collagen
Less visible in matrix of cartilage and bone
What do reticular fibers form?
Reticular fibers
Thin collagen fibers coated with glycoprotein
Form framework of such organs as spleen and lymph nodes
What are elastic fibers made of?
Elastic fibers
Thinner than collagenous fibers
Branch and rejoin each other
Made of protein called elastin
Allows stretch and recoil
Yellow fibers—fresh elastic fibers
What is ground substance usually composed of?
Ground substance (Ground substance + protein fibers = extracellular matrix)
Usually a gelatinous to rubbery consistency resulting from three classes of large molecules
Glycosaminoglycans (GAG)
Carbohydrate building blocks, some with attached amines
Play important role of regulating water and electrolyte balance in the tissues
Chondroitin sulfate—most abundant GAG
–In blood vessels and bone
–Responsible for stiffness of cartilage
Hyaluronic acid—viscous, slippery substance that forms an effective lubricant in joints and constitutes much of the vitreous body of the eyeball
What is Proteoglycan?
Gigantic molecule shaped like a test-tube brush
Proteoglycan forms thick colloids that create strong structural bond between cells and extracellular macromolecules; holds tissues together
What are Adhesive glycoproteins?
Adhesive glycoproteins bind components of tissues together
What is Areolar CT?
Loose organization of collagen and elastic fibers
Highly vascularized
Contains all fixed and wandering cells of CT proper
Ground substance is abundant and viscous
Found in the papillary layer of dermis, subcutaneous layer, and surrounding organs, nerve and muscle cells, and blood vessels
Areolar CT is a type of connective tissue
What is Reticular CT?
Meshwork of reticular fibers, fibroblasts, leukocytes
Structural framework of many lymphatic organs (e.g. spleen, thymus, lymph nodes, bone marrow)
What is Adipose CT?
Commonly referred to as fat
Composed mostly of adipocytes
Two types: White (stores energy, acts as insulator, cushions) and Brown (found in newborns, generates heat, lost as we age)
Adipose gain/loss due to adipocytes enlarging or shrinking
What is Dense Regular CT?
Tightly packed, parallel collagen fibers
Resemble stacked lasagna noodles
In tendons and ligaments
Stress typically applied in a single direction
Few blood vessels
Takes a long time to heal
What is Dense Irregular CT?
Clumps of collagen fibers extend in all directions
Provides support and resistance to stress in multiple directions
Found in dermis of skin, periosteum of bone, perichondrium of cartilage, capsules around internal organs
What is Elastic CT?
Branching, densely packed elastic fibers
Able to stretch and recoil
Found in walls of large arteries, trachea, vocal cords
What is Hyaline Cartilage?
Most common type
Clear, glassy appearance under microscope
Surrounded by perichondrium
Located in: Nose, trachea, and larynx; Costal cartilage; Articular ends of long bones; Most of fetal skeleton
What is Fibrocartilage?
Weight-bearing cartilage, resists compression
Protein fibers in irregular bundles between chondrocytes
Sparse ground substance; no perichondrium
Located in: Intervertebral discs; Pubic symphysis; Menisci of knee joint
What is Elastic Cartilage?
Flexible, springy cartilage
Numerous densely packed elastic fibers
Ensure tissue is resilient and flexible
Chondrocytes closely packed
Surrounded by a perichondrium
Located in external ear and epiglottis
What are the functions of Bone?
Levers for movement
Supports tissues
Protects vital organs
Stores minerals, e.g., calcium and phosphorus
Houses hemopoietic cells, which make blood cells
What is Blood?
Fluid connective tissue
Transports cells and dissolved matter from place to place
Plasma—blood’s liquid ground substance
Formed elements—cells and cell fragments
Bone functions
Levers for movement
Supports tissues
Protects vital organs
Stores minerals, e.g., calcium and phosphorus
Houses hemopoietic cells, which make blood cells
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Fluid CT: Blood
Fluid connective tissue
Transports cells and dissolved matter from place to place
Plasma—blood’s liquid ground substance
Formed elements—cells and cell fragments
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Muscular Tissue
Muscular tissue—elongated cells that are specialized to contract in response to stimulation
Primary job is to exert physical force on other tissues and organs
Creates movements involved in body and limb movement, digestion, waste elimination, breathing, speech, and blood circulation
Important source of body heat
Three types of muscle: skeletal, cardiac, and smooth
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Skeletal Muscle
Long, threadlike cells called muscle fibers
Most attach to bone
Exceptions: in tongue, upper esophagus, facial muscles, some sphincter muscles (ringlike or cufflike muscles that open and close body passages)
Contains multiple nuclei adjacent to plasma membrane
Striations—alternating dark and light bands
Voluntary—conscious control over skeletal muscles
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Cardiac Muscle
Cardiac muscle
Limited to the heart
cardiocytes are shorter, branched, and notched at ends
Contain one centrally located nucleus surrounded by light-staining glycogen
Intercalated discs join cardiocytes end to end
Provide electrical and mechanical connection
Striated and involuntary (not under conscious control)
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Smooth Muscle
Lacks striations and is involuntary
Relatively short, fusiform cells (thick in middle, tapered at ends)
One centrally located nucleus
Visceral muscle—forms layers of digestive, respiratory, and urinary tract: propels contents through an organ, regulates diameter of blood vessels
Nervous Tissue
Nervous tissue—specialized for communication by electrical and chemical signals in the brain, spinal cord, and nerves
Consists of neurons (nerve cells)
Detect stimuli, respond quickly
Transmit coded information rapidly to other cells
Neuroglia (glial)
Protect and assist neurons
“Housekeepers” of nervous system
Nervous Tissue - Neuron parts
Neurosoma (cell body)
Houses nucleus and other organelles
Cell’s center of genetic control and protein synthesis
Dendrites
Multiple short, branched processes
Receive signals from other cells
Transmit messages to neurosoma
Axon (nerve fiber)
Sends outgoing signals to other cells
Can be more than a meter long
Nuclei of glial cells
Membranes
Membranes line body cavities and cover their viscera
Cutaneous membrane (the skin)—largest membrane in the body
Stratified squamous epithelium (epidermis) resting on a layer of connective tissue (dermis)
Relatively dry layer serves protective function
Membranes - Mucous membrane
Mucous membrane (mucosa) lines passages that open to the external environment
Digestive, respiratory, urinary, and reproductive tracts
Absorptive, secretory, and protective functions
Membranes - Serous membrane
Serous membrane (serosa)—internal membrane
Simple squamous epithelium resting on a layer of areolar tissue
Produces serous fluid that arises from blood
Covers organs and lines walls of body cavities
Endothelium lines blood vessels and heart
Mesothelium lines body cavities (pericardium, peritoneum, and pleura)
Membranes - Synovial membrane
Synovial membrane—lines joint cavities
Areolar CT, epithelial cells secretes synovial fluid
Distributes nutrients to cartilage and reduces friction
Tissue Modification
Hypertrophy
Increase in size of existing cells of a tissue
Hyperplasia
Increase in number of cells of a tissue
Atrophy
Shrinkage of tissue by decrease in cell number or size
Due to normal aging or disuse
E.g., bed
Synovial membrane
Lines joint cavities
Areolar CT, epithelial cells secretes synovial fluid
Distributes nutrients to cartilage and reduces friction
Hypertrophy
Increase in size of existing cells of a tissue
Hyperplasia
Increase in number of cells of a tissue
Atrophy
Shrinkage of tissue by decrease in cell number or size
Due to normal aging or disuse
E.g., bedridden individual
Metaplasia
Changing from one type of mature tissue to another
Simple cuboidal tissue of vagina before puberty changes to stratified squamous after puberty
Pseudostratified columnar epithelium of bronchi of smokers to stratified squamous epithelium
Dysplasia
Abnormal tissue development
May be precancerous, or revert back to normal
E.g., cervical dysplasia due to exposure to human papillomavirus
Neoplasia
Tissue growth is out of control
Benign - Localized growth - Does not spread
Malignant - Metastasizes, spreads and invades other tissues
Necrosis
Tissue death
