Chapter 4: Tissue Level of Organization Flashcards
1
Q
Tissue
4 Types of tissue
Extracellular matrix
A
- group of similar cells and extracellular products that perform a common function
- Epithelial, connective, muscle, and nervous
- tissues vary in structure function and content of their ECM- substance produced by the cells of a specific tissue and can contain protein salts H2O and dissolved macromolecules that are located outside the cell
2
Q
Epithelial tissue
Glandular epithelial
Epithelium composure
A
- covers/lines every body surface and all body cavities, organs are lined on the outside and inside
- majority of glands are derived from epithelial tissue: small air sacs-lungs (gas exchange), small intestine (absorption)
- one or more layers of closely packed cells between compartments have different components, little to no ECM btwn epithelial cells
3
Q
Characteristics of Epithelial Tissue Cellularity Polarity Attachment Avascularity Innervation High regeneration capacity
A
- cells bound closely together by diff intercellular junctions
- Apical surface: free/top surface external environment or internal body space, Lateral surface: intercellular junctions, Basal surface: fixed/bottom surface epithelium attached to underlying connective tissue
- At basal layer, bound to thick basement membrane
- lack blood vessels, obtain nutrients by apical surface or diffusion across basal surface
- detection, nerve endings
- cells regenerate quickly
4
Q
Functions of Epithelial Tissue Physical protection Selective permeability Secretions (exocrine) Sensation
A
- dehydration, abrasion, and destruction of physical, chemical, and biological agents
- regulate the passage of certain molecules in or out of certain regions of the body
- some epithelial cells produce secretions such as sweat or oil
- posses nerve endings that can detect light, taste, sound, smell, and hearing (neuroepithelium)
5
Q
Specialized Structure of Epithelial Tissue
Basement membrane
Lamina lucida and Lamina densa
Reticular lamina
A
- single layer beneath epithelium above connective tissue, provides physical support and anchoring of epithelial tissue
- closest to epithelium, contains collagen fibers specific proteins and carbohydrate which are secreted by epithelial cells
- closest to connective tissue, contains protein fibers & carb
6
Q
Intercellular junctions Tight junctions Adhering junctions Desmosomes Hemidesmosomes Gap Junctions
A
- epithelial cells are strongly bound to each other on their lateral surfaces by sharing membrane specializations
- zonula occludens: encircles cells near their apical surface, primary function: prevent molecules from traveling in-between epithelial cells, "gatekeepers" btwn external and internal environment, 2 transmembrane proteins fuse together
- zonula adherens: formed around the cell deep to tight junction, microfilaments stabilize the apical surface of the epithelial cells, gap can increase so permeability increases, support tight junction, attach to actin cytoskeleton in cell, allows WBC to leak out and go to gametocyte
- macula adherens: button or snap between adjacent cells, hold cells together in high stress locations, consists of thickened protein plaque, intermediate filaments attach to plaques on cytoplasmic side and provide support and stability, cardiac cells/skin cells held together
- basal cells of epithelial tissue anchor them to basement membrane
- fluid-filled channels directly connect cytoplasms of apposed cells, allow communication by flow of ions and small molecular messengers
7
Q
Classification of Epithelial Tissue by Number of Cell Layer
Simple epithelium
Stratified epithelium
Pseudostratified epithelium
A
- single layer of cells with all cells having an apical surface and attached to basement membrane
- two or more layers of cells, not all cells have an apical surface nor do all cells attach to basement membrane
- cell nuclei give the appearance of multilayered epithelium, but not all cells reach the apical surface
8
Q
Classification of Epithelial Tissue by Cell Shape Squamous Cuboidal Columnar Transitional
A
- flat, wide, and somewhat irregular in shape
- same size on all sides, nucleus is usually centrally located
- taller than they are aid, nucleus is oval and located in basal region of the cell
- can change their shape/appearance based upon how stretched epithelium becomes
9
Q
Types of Epithelium(1) Simple squamous Simple cuboidal Nonciliated simple columnar Ciliated simple columnar
A
- single thin layer of flattened cells, rapid diffusion or transport of substances-capillaries, secrets serous fluid, lines inside of blood vessels, found in lung air sacs-alveoli
- single layer of cells as tall as they are wide, absorption and secretion and mucus production, forms lumen wall of kidney tubules, liver, thyroid mammary and salivary glands, and bronchioles
- single layer of cells taller than wide, no cilia, larger SA-greater exchange of material, oval nuclei in basal half of cell, brush border or microvilli, may have goblet cells-secret mucus, lining of small intestine, digestive tract
- columnar cells, some have cilia on apical surface, secretion of mucous and movement, lines luminal of uterine tubes and bronchioles
10
Q
Types of Epithelium(2) Keratinized Nonkeratinized stratified squamous Keratinized stratified squamous Stratified cuboidal epithelium Stratified columnar epithelium
A
- apical surface composed of dead cells lack nuclei, filled with tough protective keratin
- multiple layers, apical cells are squamous, resists abrasion and penetration of pathogens, lines tongue oral mucus esophagus & vagina
- multiple layers, apical cells are squamous, superficial layers contain keratin, resists abrasion, retards H2O loss through skin, resists penetration of pathogenic organisms, epidermis: palms and soles, more durable, water proofing, protect against HIV
- multiple layers of cells apical cells are cuboidal, secrets sweats, sperm production, and ovarian hormone production, sweat gland ducts in skin, ovarian follicles and seminiferous tubules
- multilayered, apical cells are columnar, protection/secretion, rare: male urethra & large ducts of some exocrine glands
11
Q
Types of Epithelium(3)
Pseudostratified columnar epithelium
Transitional epithelium
A
- single layer of columnar epithelial cells, but layered appearance of nuclei suggests multiple layers of cells, not all reach free surface but do touch basement membrane, cilia and goblet cells, protection secretion and propels mucus, resp tract and portions of male urethra
- apical cell shape changes depending on whether tissue is stretched or relaxed, distention and retraction to accommodate urine, bladder ureter (kidney to bladder) and parts of urethra (bladder to out)
12
Q
Glands-composure Stroma Parenchyma Capsule Exocrine glands Endocrine glands
A
- cell or organ that secretes or excretes substances for use in the body or releases them for elimination, composed of epithelial tissue in a connective tissue framework and capsule
- connective tissue framework of the gland, supports and organizes glandular tissue
- cells that perform the tasks of synthesis and secretion, typically cuboidal or simple columnar epithelium
- connective covering of most exocrine glands
- connected with the body surface via duct (epithelial tube conveying secretions) sweat, mammary, and tear glands
- lose their contact with the surface and have no ducts, hormones secreted into interstitial space, thyroid adrenal and pituitary glands through blood/lymph
13
Q
Exocrine Glands Simple and Compound glands Tubular Acinar Tubuloacinar gland
A
- simple unbranched and compound branched
- secretory portion and cut are uniform diameter
- secretory portion forms an expanded sac
- have both secretory tubular and secretory acinar
14
Q
Connective Tissue
Examples
A
Support protect and bind organs
Most diverse, abundant, widely distributed and structurally varied of all four tissue types
Glue and filter of the body
Tendons, ligaments, fat, bones, cartilage and blood (liquid connective tissue)
15
Q
Characteristics of Connective Tissue Cells Protein fibres Ground substance Extracellular Matrix
A
- Different cells for different types of connective tissue: fibroblast, osteocytes (bone), and adipocytes (fat)
- Strengthen and support C.T: elastic fibers, collagen, reticular fibers
- A mixture of protein and carbohydrates with variable amounts of water and salt
- Protein fibers and ground substance comprise the ECM, liquid portion
