BIO 226 - Chapter 4: The Tissue Level of Organization Flashcards

Terms Definitions
epithelial tissue
tissue that covers body surfaces and lines hollow organs, body cavities, and ducts; forms glands and some receptors
connective tissue
diverse tissue that protects and supports the body and its organs; various types bind organs together, store energy reserves as fat, and help provide immunity to disease-causing organisms
muscular tissue
tissue that generates physical force needed to make body structures move
nervous tissue
tissue that detects changes in a variety of conditions inside and outside the body and responds by generating action potentials (nerve impulses) that help maintain homeostasis
group of cells with similar structure, same embryonic origins, and are specialized for a particular function
study of tissues
study of cells and tissues to help physicians in diagnoses (disease of tissues)
primary germ layers
ectoderm (outer), endoderm (inner), mesoderm (middle)
ectoderm, endoderm, mesoderm
the first tissues formed in the human embryo
primary germ layer(s) from which epithelial tissue develops
ectoderm, endoderm, mesoderm
primary germ layer(s) from which connective tissue develops
primary germ layer(s) from which muscular tissue develops
primary germ layer(s) from which nervous tissue develops
structures to which most cells within tissue are anchored in order to remain in place
other cells, basement membrane, connective tissue (exception: phagocytes and embryonic cells involved in differentiation and growth)
steps for biopsy
sample tissue, harden with paraffin, slice thin enough for light to pass through, stain
cell junctions
points of contact between adjacent plasma membranes of tissue cells
tight junction
cell junction that consists of weblike strands of transmembrane proteins that fuse the outer surfaces of adjacent plasma membranes together; water-seal space between cells (eg. tissues that line stomach, intestines, urinary bladder)
adherens junction
cell junction that often forms extensive zones called adhesion belts because they encircle the cell; help epithelial surfaces resist separation during various contractile activities
cell junction that contains plaque and has transmembrane glycoproteins that extend into intercellular space between adjacent cell membranes and attach cells to one another (eg. epidermis, cardiac muscle cells)
cell junction that resembles desmosomes but do not link adjacent cells; anchor cells to the basement membrane
gap junction
cell junction that allow for communication and certain substances to pass from cell to cell through very narrow intercellular gap
apical (free) surface
surface of epithelial cell that faces the body surface, a body cavity, the lumen (interior space) of an internal organ, or a tubular duct that receives cell secretions; may contain cilia or microvilli
lateral surface
surface of epithelial cell that faces adjacent cells on either side; may contain tight, adherens, desmosomes and/or gap juntions
basal surface
surface of epithelial cell that adhere to extracellular materials such as the basement membrane
apical layer
most superficial layer of cells in epithelial tissue
basal layer
deepest layer of cells in epithelial tissue
basement membrane
thin extracellular layer that commonly consists of two layers: basal lamina and reticular lamina
basal lamina
layer of basement membrane that is closer to (and secreted by) epithelial cells; contains proteins such as collagen and laminin
reticular lamina
layer of basement membrane that is closer to underlying connective tissue and contains fibrous proteins produced by connective tissue called fibroblasts; made of reticular fibers
functions of basement membrane
point of attachment and support for overlying epithelial tissue; allows for diffusion of materials; guide for cell migration during development; may become thickened due to increased collagen and laminin production, necessary for wound repair
epithelial tissue - general features
closely packed cells with little extracellular material; cells sit on basement membrane; avascular (for MOST of this type of tissue), good nerve supply, rapid cell division
epithelial tissue - functions
protection, filtration, lubrication, secretion, digestion, absorption, transportation, excretion, sensory reception, reproduction
types of epithelium
covering and lining; glandular; some receptors
covering and lining epithelium
forms epidermis of skin, linings of blood vessels, ducts, hollow organs (respiratory, reproductive, urinary and GI tracts)
epithelial arrangement of cells in layers
simple (one layer thick); stratified (2+ layers thick); pseudostratified (cells contact basement membrane but not all reach apical surface)
epithelial arrangement of cells by shape
squamous (flat, tile-like); cuboidal (cube-shaped), columnar (taller than they are wide); transitional (change shape)
simple squamous epithelium
single layer of flat cells; adapted for diffusion/filtration; nucleus of each cell flattened and centrally located; "endothelium" lines heart, blood vessels, lymphatic vessels; "mesothelium" lines thoracic and abdominopelvic cavities, covers organs within them, and forms epithelial layer of serous membranes (peritonem, pericardium, pleura)
simple cuboidal epithelium
cell nuclei round and centrally located; adapted for secretion and absorption; found in organs such as thyroid gland and kidneys
nonciliated simple columnar epithelium
contrain 2 types of cells: columnar epithelial cells with microvilli at apical surface and goblet cells; lines digestive tract
fingerlike cytoplasmic projections that increase surface area of the plasma membrane and increase rate of absorption by the cell
goblet cells
modified columnar epithelial cells that secrete mucus at apical surfaces
ciliated simple columnar epithelium
contains goblet cells and columnar epithelial cells with cilia at apical surface that beat in unison to move mucus and any foreign particles along the surface; found in upper respiratory tract and uterine tubes
pseudostratified ciliated columnar epithelium
cells that extend to surface either secrete musuc or bear cilia
pseudostratified nonciliated columnar epithelium
contains cells without cilia and lacks goblet cells
stratified squamous epithelium
apical layer of cells are flat, deep layer of cells vary in shape; basal cells continually replicate by mitosis and replace surface cells as they are lost; serves for protection
keratinized stratified squamous epithelium
cells in apical layer and several layers deep to it are partially dehydrated and contain layer of keratin; forms superficial layer of skin
tough, fibrous protein that helps protect skin and underlying tissues from heat, microbes, and chemicals
nonkeratinized stratified squamous epithelium
does not contain keratin in the apical layer and remains moist; found lining the mouth, esophagus, vagina
stratified cuboidal epithelium
rare type of epithelium; mainly serves protective function and limited secretion/absorption
stratified columnar epithelium
rare type of epithelium; basal layers consist of shortened, irregularly shaped cells; apical layer consists of columnar cells; functions in protection/secretion
transitional epithelium
present only in urinary system and has variable appearance that allows for stretching; ideal for lining hollow structures that are subjected to expansion from within
glandular epithelium
functions in secretion and is accomplished by glandular cells that often lie in clusters deep to the covering and lining epithelium
may consist of single cell or group of cells adapted to secrete substances into ducts (tubes), onto a surface, or into the blood
endocrine glands
secretions from these glands (hormones) enter the interstitial fluid and diffuse directly into the bloodstream without flowing through a duct (eg. pituitary, thyroid, adrenal glands)
secretions that regulate many metabolic and physiological activities to maintain homeostasis
exocrine glands
can be uni- or multi-cellular; glands that secrete products into ducts that empty onto the surface of a covering and lining epithelium such as the skin surface or the lumen of a hollow organ
unicelluar glands
single-celled; eg. goblet cells secrete mucus directly onto the apical surface of a lining epithelium
multicellular glands
composed of many cells; eg. sudoriferous, sebaceous, salivary glands; categorized according to branched/unbranched ducts and shape of secretory portions of gland
simple gland
gland does not branch
compoud gland
gland branches
tubular gland
glands with tubular secretory parts
acinar glands
glands with more rounded secretory parts
tubuloacinar glands
glands that have both tubular and more rounded secretory parts
merocrine glandsd
most common type of exocrine gland in body; secretions are released from cell in secretory vesicles via exocytosis; eg. salivary and sweat glands, pancreas
apocrine glands
accumulate secretory product at the apical surface of the secreting cell, then port pinches off to release secretion (remaining part of cell repairs itself and repeats)
holocrine glands
accumulate secretory product in their cytosol and as secretory cell matures, it ruptures, becomes the secretory product and is replaced by a new cell; eg. oil gland
connective tissue - general features
diverse, abundant and widely distributed; derived from mesoderm/mesenchyme; cells rarely touch due to extracellular matrix; highly vascular and good nerve supply except in cartilage and tendons
extracellular matrix
material located between connective tissue's widely spaced cells; consists of protein fibers and ground substance; usually secreted by tissue cells and determines tissue's qualities
most numerous connective tissue cells that secrete fibers and matrix; large, flat cells with branching processes
fat cells that store triglycerides; found deep to the skin and around organs such as the heart and kidneys
develop from monocytes (type of white blood cell); irregular shape with short branching projections; engulf bacteria and debris by phagocytosis; can be fixed or "wandering"
plasma cells
develop from B lymphocyte (type of white blood cell); secrete antibodies that attack or neutralize foreign substances
mast cells
abundant alongside blood vessels that supply connective tissue; produce histamine that dilates small blood vessels as part of inflammatory response
white blood cells
not found in significant numbers in normal connective tissue, but migrate into tissues in response to certain conditions
cardinal signs of inflammation
tumor (swelling), calor (heat), dolor (pain), rubor (redness)
ground substance
component of connective tissue between cells and fibers; may be fluid, semifluid, gelatinous or calcified
ground substance - functions
supports cells, binds them together, stores water, provides medium through which substances are exchanged between blood and cells; plays active role in how tissues develop, migrate, proliferate, change shape, and in how they carry out their metabolic functions
glycosaminoglycans (GAGs)
collective same for the polysaccharides found in ground substance; includes: hyaluronic acid, chondroitin sulfate, dermatan sulfate, keratan sulfate
hyaluronic acid
viscous, slippery substance that binds cells together, lubricates joints, and helps maintain shape of eyeballs
chondroitin sulfate
jellylike substance that provides support and adhesiveness in cartilage, bone, skin, and blood vessels
adhesion proteins
responsible for linking components of the ground substance to one another and to the surfaces of cells; eg. fibronectin binds to both collagen fibers and ground substance
fibers in extracellular matrix
function to strengthen and support connective tissues; three types: collagen, elastic, and reticular
collagen fibers
thick, ropelike, very strong and resist pulling forces; often occur in bundles adding strength; flexible; found in bone, cartilage, tendons, ligaments
elastic fibers
branch and join together to form network within tissue; highly coiled and capable of stretching; composed of protein molecules elastin and surrounded by glycoprotein fibrillin; found in skin, blood vessel walls, lung tissue
reticular fibers
consists of collagen arranged in fine bundles with a coating of glycoprotein; provides support in walls of blood vessels, spleen, lymph nodes and form network around cells in some tissues; form branching networks for support and strength;
types of embryonic connective tissue
mesenchyme, mucous connective tissue
found exclusively in embryo; tissue form from which all other connective tissues eventually arise; composed of ireegularly shaped cells, semifluid ground substance, delicate reticular fibers
mucous connective tissue (wharton's jelly)
found in umbilical cord of fetus; contains widely scattered fibroblasts, jellylike ground substance, collagen fibers
types of mature connective tissue
loose connective, dense connective, cartilage, bone, liquid connective
loose connective tissue
fibers loosely intertwined between cells; contains all 3 types of fibers, several types of cells, semifluid ground substance; subtypes include areolar, adipose, reticular
areolar connective tissue
widely distributed connective tissue; types of cells include fibroblasts, macrophages, plasma cells, mast cells, adipocytes, few white blood cells; fibers include collagen, elastic, reticular that are randomly arranged; gelatinous ground substance, forms subcutaneous layer of integument (with adipose tissue); nucleir are mostly fibroblasts
adipose connective tissue
adipocytes are specialized for storage of triglycerides; found wherever areolar tissue is located; nucleus pushed to periphery of cell; good insulator, reduces heat loss through skin, serves as energy reserve, supports and protects various organs; brown fat found in newborn and produces heat, yellow fat found in adults
reticular connective tissue
consists of fine interlacing reticular fibers that reticular cells; forms the stroma (supporting framework) of liver, spleen, lymph nodes and helps bind together smooth muscle cells
dense connective tissue
contains more numerous, thicken, and denser fibers but fewer cells than loose connective tissue; subtypes classified by predominant fibers and arrangement
dense regular connective tissue
bundles of collagen fibers arranged in parallel patterns that provide tissue with great strength; withstands pulling along axis of fibers; fibroblasts appear in rows between fibers; tissue is silvery white and tough but pliable; eg. tendons and most ligaments
dense irregular connective tissue
collagen fibers packed closely together; found in parts of body where pulling forces are exerted in various directors; often occurs in sheets (eg. dermis of skin); found in heart valves, perichondrium, periosteum; little ground substance, few cells, avascular, no nerves
elastic connective tissue
branching elastic fibers and fibroblasts in between; strong and can recoil after stretching; found in lung tissue, vocal chords, ligaments between vertebrae
dense network of collagen fibers (strength and flexibility), and elastic fibers firmly embedded in chondroitin sulfate (resilience); chondrocytes occur in spaces called lacunae in matrix; covered by a membrane of perichondrium (dense irregular tissue); no blood vessels or nerves
hyaline cartilage
most abundant; weakest; has fine collagen fibers embedded in gel-like matrix; flexibility and support; reduces friction at joints and absorbs shock (articular cartilage); bluish-white, shiny, rubbery; avascular slows repair
contains bundles of collagen in matrix; lacks perichondrium; strongest type of cartilage (eg. intervertebral discs); rigid and stiff; found on or next to midline
elastic cartilage
threadlike network of elastic fibers; has perichondrium; strong and elastic; maintains shape of certain organs; found in ears, nose
growth of cartilage
interstitial growth, appositional growth
interstitial growth
growth from within; cartilage increases rapidly in size due to division of existing chondrocytes and continuous deposition of matrix; occurs while cartilage is young and pliable during childhood/adolescence
appositional growth
growth in width; fibroblasts in perichondrium divide and some differentiate into chondroblasts; chondroblasts surround themselves with new matrix and become chondrocytes
bone (osseous) tissue
protects, provides for movement, stores minerals, site of blood cell formation; consists of matrix containing mineral salts and collagenous fibers and cells called osteocytes; subtypes include spongy and compact
compact bone
solid bone, dense; basic unit of structure is osteon (haversian system)
concentric rings of extracellular matrix that consist of mineral salts (calcium, phosphate) for hardness and collagen fibers for strength
small spaces between lamellae that contain mature bone cells called osteocytes
minute canals containing processes of osteocytes that provide routes for nutrient and waste transport
central (haversian) canal
contains blood vessels and nerves
spongy bone
lacks osteons; consists trabeculae
columns of bone that contain lamellae, osteocytes, lacunae and canaliculi; surrounded by red bone marrow
blood tissue
connective tissue with liquid extracellular matrix called blood plasma and formed elements
blood plasma
pale yellow fluid that consists mostly of water with a variety of dissolved substances: nutrients, wastes, enzymes, plasma proteins, hormones, respiratory gases, ions
formed elements
red blood cells, white blood cells, platelets suspended in blood plasma; responsible for clotting, immune functions, transport of O2 and CO2
interstitial fluid flowing in lymphatic vessels; less protein than blood plasma; move cells and substances from one part of body to another; no fibers- does not clot
liquid connective tissue
main function is transport and defense against pathogens
flat sheets of pliable tissue that cover or line a part of the body
epithelial membranes
consist of epithelial layer and an underlying connective tissue layer (lamina propria) that provides nourishment to epithelia
mucous membrane
lines a body cavity that opens directly to exterior; epithelial layer forms barrier to microbes and other pathogens; tight junctions connect cells; goblet cells secrete mucus; connective tissue later is lamina propria
lamina propria
areolar connective tissue that supports epithelium, binds it to the underlying structures, and allows some flexibility of the membrane; holds blood vessels in place and protects underlying structures from abrasion or puncture; O2 and nutrients diffuse from lamina propria to epithelium
serous membranes
lines a body cavity that does not open directly to exterior; covers organs that lie within the cavity; consist of areolar tissue covered by mesothelium; two layers: parietal and visceral
parietal layer of serous membrane
layer attached to cavity wall
visceral layer of serous membrane
layer that covers and attaches to the organs inside the cavity
serous fluid
secreted by mesothelium of a serous membrane; watery lubricant that allows organs to slide easily over one another or to slide against walls of cavities
serous membrane that lines thoracic cavity and covers lungs
serous membrane that lines heart cavity and covers heart
serous membrane that lines abdominal cavity and covers abdominal organs
cutaneous membrane (skin)
covers surface of body and consists of superficial portion called epidermis and deeper portion called dermis; lamina propria is dermis
synovial membrane
lines cavities of freely movable joints; lack an epithelium and are not epithelial membranes (contain only connective tissue); composed of discontinuos layer of synoviocytes that secrete synovial fluid and a layer of connective tissue deep to the synoviocytes
synovial fluid
lubricates and nourishes cartilage covering the bones at movable joints and contains macrophages that remove microbes and debris from joint cavity
muscular tissue - general features
consist of elongated cells called muscle fibers that can use ATP to generate force; classified into three types: skeletal, cardiac, smooth
muscular tissue - functions
produces body movements, maintains posture, generates heat, provides protection
skeletal muscle tissue
attached to bone; striated; voluntary; fibers are long, roughly cylindrical in shape, many nuclei on periphery; fibers are parallel
cardiac muscle tissue
formes most of the wall of the heart; striated; involuntary; fibers are branched and have one centrally located nucleus; attached to one another and communicate via intercalated discs and desmosomes
smooth muscle tissue
located in walla of hollow internal structures; no striations, involuntary; fibers are small and spindle shaped with a single, centrally located nucleus
nervous tissue
composed of two principal types of cells: neurons and neuroglia
nerve cells; sensitive to various stimuli; convert stimuli into electrical signals; conduct impulses to other neurons, musicle fibers, glands; 3 basic parts: cell body, dendrites, axons
action potentials
electrical signals; nerve impulses
cell body of neuron
contains nucleus and other organelles
tapering, highly branched, usually short cell processes that are the major receiving or input portion of a neuron
single, thin, cylindrical process that may be very long that is the output portion of a neuron; conduct nerve impulses toward another neuron or to some other tissue
protecting and supporting cells; often the site of tumors because they can divide
excitable cells
neurons and muscle fibers; exhibit electrical excitability (ability to respond to certain stimuli by producing electrical signals such as action potentials)
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