Principles of Anatomy and Physiology: The Tissue Level of Organization

Flashcards on Tissues

What is a Tissue?

A group of cells that usually have a common embryonic origin and function together to carry out specialized activities

What are the 4 Basic Tissue Types?

Epithelial, Connective, Muscular, and Nervous

What is the function of Epithelial tissues?

Cover body surfaces, form glands and line hollow organs, body cavities, and ducts; specialized to secrete, filter and absorb

What is the function of Connective tissues?

Protect, support, and bind organs; Fat stores energy; Red blood cells, white blood cells, and platelets

What is the function of Muscular tissues?

Generate the physical force needed to make body structures move and generate heat used by the body

What is the function of Nervous tissues?

Detect changes in the body and respond by generating nerve impulses

What are the three primary germ layers?

Ectoderm, Endoderm and Mesoderm

Which tissues are derived from all three germ layers?

Epithelial tissues

Which tissues are derived from mesoderm?

C.T. and muscle

Which tissues are derived from ectoderm?

Nervous tissue

What are Intercellular Junctions?

Connect adjacent cells mechanically at plasma membranes of cells or through cytoskeletal elements within and between cells

What are the 5 main types of cell junctions?

Tight, Adherens, Desmosomes, Hemidesmosomes, Gap

What are Tight Junctions?

Web like strands of transmembrane proteins that fuse together outer surfaces of adjacent cells

What are Adherens Junctions?

Adhesion belt of proteins attaching to microfilaments that keeps tissues from separating as they stretch and contract

What are Desmosomes?

Act as “spot welds” using cadherin glycoprotein (plus intermediate filaments made of keratin) to hook into the cytoplasm

What are Hemidesmosomes?

Half-welds that join cells to the basement membrane and not to each other

What are Gap Junctions?

Pores (Connexons) that allow small substances like ions to pass between cells, but not large molecules

What are the General Features of Epithelial Tissue?

Cells are arranged in sheets and are densely packed; Many cell junctions are present; Epithelial cells attach to a basement membrane; Epithelial tissue is avascular but does have a nerve supply; Mitosis occurs frequently

How are Covering and lining epithelia classified?

Shape of the cells and how many layers thick they are

What are the classifications of Epithelial Tissues?

Arrangement of layers: simple (1 layer), stratified (2 or more layers); Cell shape: squamous (thin and flattened), cuboidal (cube-shaped), columnar (tall and elongated)

What is Simple Squamous Epithelium?

Single layer of flat cells that resembles a tiled floor when viewed from apical surface; centrally located nucleus

What is Simple Cuboidal Epithelium?

Single layer of cube-shaped cells; round, centrally located nucleus

What is Non-ciliated Simple Columnar Epithelium?

Single layer of non-ciliated column like cells with oval nuclei near base of cells; contains 1) columnar epithelial cells with microvilli at apical surface and 2) goblet cells

What is Ciliated Simple Columnar Epithelium?

Single layer of ciliated column-like cells with oval nuclei near base of cells

What is Non-ciliated Pseudostratified Columnar Epithelium?

Appears to have several layers because the nuclei are a various levels. Even though the cells are attached to the basement membrane in a single layer, some cells do no extend to the apical surface

What is Ciliated Pseudostratified Columnar Epithelium?

Appears to have several layers because cell nuclei are at various levels; Contains cells that extend to surface and secrete mucus (goblet cells) or bear cilia

What is Stratified Squamous Epithelium?

Contains two or more layers of cells. Cells in apical layer and several layers deep to it are squamous; cells in deeper layers are cuboidal and columnar

What is Stratified Cuboidal Epithelium?

Has two or more layers of cells; cells in apical layer are cube-shaped; fairly rate type

What is Stratified Columnar Epithelium?

Basal layers consist of shortened, irregularly shaped cells; only apical layer has columnar cells; uncommon

What is Urothelium (Transitional Epithelium)?

Has a variable appearance (transitional). In relaxed or unstretched state, looks like stratified cuboidal epithelium, except apical layer cells tend to be large and rounded

What is a gland?

A single cell or a mass of epithelial cells adapted for secretion

What are Endocrine Glands?

Endocrine gland secretions (hormones) enter interstitial fluid and then diffuse into bloodstream without flowing through a duct

What are Exocrine Glands?

Exocrine gland secretory products are released into ducts that empty onto surface of a covering and lining epithelium, such as skin surface or lumen of hollow organ

What is the Structural Classification of Glandular Epithelium?

Unicellular and Multicellular

What are the three types of exocrine glands?

Merocrine, Apocrine, and Holocrine glands

What gland secretes a fluid product released through the cell membrane by exocytosis?

Merocrine glands

What gland releases by shedding part of the cell’s cytoplasm?

Apocrine glands

What gland releases by the whole cell disintegrating?

Holocrine glands

What are the two basic elements of Connective Tissue?

Cells and Extracellular matrix

What are the Fibers in the extracellular matrix?

Collagen fibers, Elastic fibers, and Reticular fibers

What is the Classification of Connective Tissue?

Loose connective tissue, Dense connective tissue, Cartilage, Bone, Blood

What are the types of Loose Connective Tissue?

Areolar, Adipose, Reticular

What is Adipose tissue (fat)?

Contains adipocytes, which store fat in cytoplasm

What is Areolar tissue?

Forms thin, delicate membranes; Main cell type is fibroblasts

What is Reticular connective tissue?

Contains thin, reticular fibers; Fibers form a 3-dimensional network

What is Dense Connective Tissue?

Consists of densely packed collagen and elastic fibers; Contains few cells; most are fibroblasts

What are the Three Types of Cartilage?

Hyaline, Elastic, Fibro

What is Hyaline Cartilage?

Contains fine collagen fibers in matrix; appears glassy

What is Elastic Cartilage?

Contains elastic fibers in dense network; flexible

What is Fibrocartilage?

Tough tissue containing many collagenous fibers

What are the 2 types of bone tissue?

Compact and Spongy

What does blood consist of?

Consists of blood plasma and formed elements: red blood cells (erythrocytes), white blood cells (leukocytes), platelets (thrombocytes)

What are the 3 types of muscle tissue?

Skeletal muscle, Cardiac muscle, Smooth muscle

What is Skeletal Muscle Tissue?

Consists of long, cylindrical, striated fibers

What is Cardiac Muscle Tissue?

Consists of branched, striated fibers with usually only one centrally located nucleus

What is Smooth Muscle Tissue?

Consists of nonstriated fibers (lacking striations, hence the term smooth)

What are the two kinds of cells in Nervous Tissue?

Neurons and Neuroglia

What is the function of Nervous Tissue?

Exhibit sensitivity to various types of stimuli; converts stimuli into nerve impulses (action potentials); conducts nerve impulses to other neurons, muscle fibers, or glands

What are the 2 types of Membranes?

Epithelial membranes and Synovial membranes

What are the types of Epithelial membranes?

Mucous membranes, Serous membranes, Cutaneous membranes