Ch. 3 Tissues Flashcards Preview

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Flashcards in Ch. 3 Tissues Deck (87):

Connective Tissue

protects and supports the body and its organs;
binds organs together, store energy reserves as fast, and helps provide body with immunity to disease-causing organisms


Muscular Tissue

composed of cells specialized for contraction and generation of force, generates heat that warms the body


Nervous Tissue

detects changes inside and outside the body and responds by generating electrical signals called nerve potentials that activate muscular contractions and glandular secretions


Cell Junctions

contact points between plasma and membranes of tissue cells


Tight Junctions

weblike strands of transmembrane proteins that fuse together the outer surfaces of adjacent plasma membranes to seal off passageways between adjacent cells; impermeable
Ex. Stomach, intestine, urinary bladder


Adherens Junctions

contain plaque; dense layer of proteins on the inside of the plasma membrane that attaches both to membrane proteins and to microfilaments of the cytoskeleton
Permeable, resist separation
Ex. Lining of intestine



transmembrane glycoproteins join the cells; inserts into the plaque from the opposite side of the plasma membrane; crosses intercellular space, and connects to a cadherin of an adjacent cell



contain plaque and have transmembrane glycoproteins that extend into the intercellular space between adjacent cell membranes and attach cells to one another; does not attach to microfilaments instead attached to elements of the cytoskeleton known as intermediate filaments; contributes to stability of the cells and tissue, prevent from separating under tension and cardiac muscle cells from pulling apart; permeable
Ex. Outer layer of skin and heart muscles



resemble desmosomes but do not link adjacent cells; transmembrane glycoproteins are called intergrins
intergrins attach to intermediate filaments made of protein keratin on the inside of the plasma membrane, on the outside of the plasma membrane, intergrins attach to the protein laminin
anchor to the basement membrane vs one another


Gap Junctions

membrane proteins called connexins form tiny fluid filled tunnels called connexons that connect neighboring cells
separated by a very narrow intercellular gap, ions and small molecules can diffuse from the cytosol of one cell to another but passage of large molecules is prevented
communicate with one another, enable nerve or muscle impulses to spread rapidly among cells
Ex. Lens, cornea, nerves and muscles


Epithelial Tissue

covers body surfaces, and lines hollow organs, body cavities, and ducts; also forms glands
allows body to interact with both internal and external enviroments


Epithelial VS Connective Tissue

tightly packed together with little extracellular matrix- large amount of extracellular matrix separates cells
no blood vessels- networks of blood vessels
always forms surface layers and not covered by another tissue (except within blood vessels)
always found immediately adjacent to blood-vessel-rich connective tissue, enables exchanges with blood



cells in continuous sheets, little intercellular space between adjacent plasma membranes, forms coverings and linings throughout the body
1. serves as a selective barrier to limit or aid transfer of substances
2. releases products produced by the cells onto its free surfaces
3. protects against the abrasive influences of the environment


apical (free) surface

faces the body surface, a body cavity, lumen of an internal organ, or tubular duct; may contain cilia or microvilli


Lateral Surfaces

face adjacent cells on either side, may contain cell junctions


Basal Surface

opposite the apical surface; adhere to extracellular materials such as the basement membrane (hemidesmosomes)
apical layer: superficial layer of cells
basal layer: deepest layer of cells


Basement Membrane

thin extracellular layer that consists of two layers;
basal lamina: closer to and secreted by the epithelial cells, consists of proteins and glycoproteins and proteoglycans (laminin adhere to integrins)
reticular lamina: closer to underlaying connective tissue and contains proteins
form a surface to migrate during growth or wound healing, restrict larger molecules between epithelium and connective tissue, participate in filtration of blood in the kidneys



no blood vessels


Covering and Lining Epthelium

forms outer covering of the skin and some internal organs, forms the inner lining of blood vessels, ducts, and body cavities, and interior of the respiratory, digestive, urinary, and reproductive systems


Glandular Epthelium

makes up secreting portion of glands such as the thyroid, adrenal, and sweat glands


Arrangement of Cells in Layers

a) simple (unilaminar) epithelium: single layer of cells that diffuse, osmosis, filtration, secretion, absorption
b) pseudostratified epithelium: appears to have multiple layers of cells because cell nuclei lie at different levels and not all cells reach apical surface, all cells rest on the basement membrane
c) stratified (multilaminar) epithelium: consists of two or more layers of cells that protect underlying tissues in locations of wear and tear


Cell Shapes

a) squamous cells: thin, allow rapid passage of substances through them
b) cuboidal cells: tall as they are wide, shaped like hexagons or cubes, have microvilli at their apical surface and function in secretion or absorption
c) columnar cells: much taller than wide, protect underlying tissues, apical surfaces may have cilia or microvilli, secretion and absorption
d) transitional cells: change shape, squamous to cuboidal and back, as organs stretch to a larger size and then collapse small


Simple Squamous Epithelieum

single layer of flat cells; centrally located nucleus that is flattened and oval
endothelium: lines cardiovascular and lymphatic system
Mesothelium: serous membrane
air sacs of lungs, capsule of kidneys, inner surface of tympanic membrane
present where process of filtration, diffusion, absorption and secretion occur


Simple Cuboidal Epithelium

single layer of cube-shaped cells, round, centrally nucleus
covers surface of ovary, lines anterior surface of capsule of the lens of the eye, forms pigmented epithelium at posterior surface of the retina, lines kidney tubules and smaller ducts of many glands, makes up secretory portion of glands
secretion and absorption


Nonciliated simple columnar epthelium

single layer nonciliated column like cells with oval nuclei near base of cells;
mircovilli: fingerlike cytoplasmic projections, increase surface area of plasma membrane, increase rate of absorption by cell
goblet cells: modified columnar epithelial cells, mucus
lines the gastrointestinal tract, ducts of glands and gallbladder
secretion and absorption, lubricant, prevent destruction of stomach lining; capable of higher level of secretion/absorption


Ciliated Simple Columnar Epithelium

single layer ciliated column cells with oval nuclei near base; upper resp. tract, goblet cells are interspersed
lines some bronchioles of resp tract, uterine tubes, uterus, paranasal sinuses, central canal of spinal cord, ventricles of the brain
cilia beat in unison, moving mucus toward throat, coughing/sneezing speeds up movement, help move oocytes expelled from ovaries through tube


Pseudostratified Columnar Epithelium

nuclei of cells are at various layers, all attached to basement membrane
ciliated= contains cells that extend to surface and either secrete mucus or bear cilia
unciliated= contains cells without cilia and lack goblet cells
lines airways of upper resp. tract vs lines larger ducts of many glands, epididymis and male urethra
secrete mucus that traps foreign particles, sweep away mucus vs absorption and protection


Stratified Squamous Epithelium

two or more layers of cells; apical layer are squamous; at apical layer, dead cells lose cell junction
Keratinized SSE develop tough layer of keratin in apical layer; more keratin farther away from blood supply
Nonkeratinized constantly moistened by mucus (organelles not replaced)
keratinized form superficial layer of skin; non lines wet surfaces
protects against abrasion, water loss, ultraviolet radiation, foreign invasion, form the first line of defense against microbes


Stratified Cuboidal Epithelium

two or more layers of cells, apical layer are cube-shaped (rare type)
ducts of adult sweat glands and esophageal glands and part of male urethra
protection and limited secretion and absorption


Stratified Columnar Epithelium

basal layers consist of shortened shaped cells; only apical layers have columnar in shape (uncommon)
lines part of urethra, large excretory glands, small area in anal mucous membrane, part of conjunctive of eye
protection and secretion


Transitional Epithelium

relaxed- stratified cubodial ( apical layer are large and rounded)
stretched- cells become flatter, stratified squamous
ideal for lining hollow structures that are subject to expansion
lines urinary bladder and portions of ureter and urethra
allows organs to strech to hold a variable amount of fluid without rupturing



single or group of cells that secrete substances via ducts onto a surface, or into the blood in the absence of ducts


Endocrine Glands

enter ICF and diffuse directly into the bloodstream without flowing through a duct; hormones regulate activities to maintain homeostasis; far-reaching effects because distributed throughout the body


Exocrine Glands

secrete their products into ducts that empty onto the surface of a covering or lining epithelium; limited effects, harmful if entered bloodstream


Unicellular Glands

single-celled glands; goblet cells secrete mucus directly onto the apical surface of a lining epithelium


Multicellular Glands

composed of many cells that form a distinctive microscope structure or macroscopic organ; ex. salivary, sudoriferous and oil glands


Simple vs Compound vs Tubular vs Acinar Glands (Multicellular Glands)

duct of gland does not branch
duct branches
gland with tubular secretory parts
rounded secretory portions


Tubuloacinar Glands

have both tubular and more rounded secretory parts


Simple Tubular

tubular secretory part is straight and attaches to a single unbranched duct


Simple Branched Tubular

tubular secretory part is branched and attaches to a single unbranched duct
ex. gastric glands


Simpled Coiled Tubular

Tubular secretory part is coiled and attaches to a single unbranched duct
ex. sweat glands


Simple Acinar

Secretory portion is rounded and attaches to a single unbranched duct
ex. glands of the penile urethra


Simple Branched Acinar

rounded secretory part is branched and attaches to a single unbranched duct
ex. sebaceous glands


Compound Tubular

secretory part is tubular and attaches to a branched duct
ex. Cowper's Gland


Compound Acinar

Secretory portion is rounded and attaches to a branched duct
ex. mammary glands


Compound Tubuloacinar

secretory portion is both tubular and rounded and attaches to a branched duct
ex. acinar glands of the pancreas


Merocrine Glands (Eccrine glands)

synthesized on ribosomes attached to rough ER; processed, stored, and packaged by the Golgi complex; and released from the cell in secretory vesicles via exocytosis
ex. salivary gland and pancreas


Apocrine Glands

accumulate their secretory product at the apical surface of the secreting cell, then pinched off from the rest of the cell to release secretion, remaining part repairs itself and repeats
ex. mammary glands produce milk fats and some sweat glands in axillary and pubic region


Holocrine Glands

accumulate a secretory product in their cytosol, as it matures it ruptures and becomes the secretory product. consists of lipids from the plasma membrane and intercellular membranes. cell is replaced by a new cell
ex. sebaceous (oil) gland of the skin


Extra cellular Matrix

Water, fibers, proteins


General Features of Connective Tissue

cells separated by an extracellular matrix that consists of ground substance and fibres; variable qualities; fibres are secreted by the connective tissue cells
not usually located on free surfaces
highly vascular
has a nerve supply (except cartilage)
solid-bone, semisolid- cartilage, liquid-blood


Characteristics of Connective Tissue

derived from mesenchyme
immature cells have names that end with -blast (stem cell); retain capacity for cell division and secrete the matrix
mature cells have names that end with -cyte (osteocytes-bone, chondrocytes-cartilage, RBC/WBC-blood); usually have a reduced capacity for cell division and matrix secretion; maintain matrix



large, flat cells with branching processes; present in all general connective tissue, migrate through connective tissue, secreting fibres and extracellular matrix



develop from monocytes; irregular shape with short branching projections and are capable of engulfing bacteria ad cellular debris by phagocytosis


Plasma Cells

small cells that develop from a type of white blood cell called B lymphocyte; secrete antibodies, proteins that attack foreign substances, most reside in connective tissue (gastrointestinal and respiratory tracts)


Mast Cells

abundant alongside the blood vessels that supply connective tissue; produce histamine, chemical dilates small blood vessels (inflammatory response), reaction to injury or infection; bind to, ingest, and kill bacteria



fat cells that store triglycerides; found deep to the skin and around organs such as heart or kidneys


White Blood Cells

not found in significant numbers, migrate from blood into connective tissue


Ground Substance

component of connective tissue between cells and fibres; maybe fluid, semifluid, gelatinous, or calcified; supports cells, binds them, stores water, and provides a medium for exchange


Glycosaminoglycans (GAGs)

polysaccharides in ground substance; associated with proteoglycans- forms the support structure
trap water, making ground substance more jellylike


Collagen Fibers

very strong and resist pulling forces, are not stiff, allows tissue flexibility; most abundant protein in body


Elastic Fibers

smaller in diameter than collagen, branch and join together to form a fibrous network within tissue; strength and stability
skin, blood vessel walls, lung tissue


Reticular FIbers

consisting of collagen arranged in fine bundles, provide support in the walls of blood vessels
much thinner than collagen fibers and form branching networks support and strength
stroma- supporting framework of many soft organs, also form basement membrane


Mature Connective Tissue

present in newborn; arise from mesenchyme


Areolar Loose Connective Tissue

consists of fibers (all 3) arranged randomly and several kinds of cells embedded in semifluid ground substance
most widely distributed connective tissue, subcutaneous layer deep to skin, papillary region of dermis of skin, lamina propria of mucous membranes, around blood vessels, nerves and body organs "packing material"
strength, elasticity, and support


Adipose Tissue

adipocytes are specialized for storage of triglycerides as a large centrally located droplet, as a person gains weight adipose tissue increase and new blood vessel form- cause high blood pressure (white adipose tissue)
(brown adipose tissue)- obtains darker color from very rich blood supply, widespread in fetus and infants
found wherever areolar connective tissue is located, deep to skin, around heart and kidneys, yellow bone marrow, and padding around joints and behind eyeball socket
reduces heat loss through skin, serves as energy reserve, and supports and protects organs; newborns- BAT generate heat (mitochondria)


Reticular Connective Tissue

consists of interlacing network of reticular fibers and reticular cells
stroma of liver, spleen, lymph nodes, red bone marrow; reticular lamina of the basement membrane; around blood vessels and muscles
forms stroma of organs, binds together smooth muscle tissue cells; filters and removes worn-out blood cells in the spleen and microbes in lymph nodes


Dense Connective Tissue

contains fibers, which are thicker and more densely packed but has considerably fewer cells than loose connective tissue


Dense Regular Connective Tissue

Extracellular matrix less water more fiber, consists mainly of collagen fibers regulary arranged in bundle with fibroblasts present in rows between bundles, are not living, slow to heal following damage (few blood cells)
forms tendons, most ligaments, aponeuroses (sheetlike tendons that attach muscle to muscle or muscle to bone)
provides strong attachment between various structures, withstands pulling along the long axis of the fibers


Dense Irregular Connective Tissue

Contains tightly packed, woven meshes of collagen fibers that are usually irregularly arranged
tissue often occurs in sheets, fasciae, reticular region of dermis of skin, fibrous pericardium of heart, periosteum of bone, perichondrium of cartilage, joint capsules, membrane capsules around various organs, also heart vales
provides tensile (pulling) strength in many directions


Elastic Connective Tissue

consists predominantly of elastic fibers with fibroblasts in spaces between the fibers, unstained tissue has a yellowish color
lung tissue, walls of elastic arteries, trachea, bronchial tubes, true vocal chords, suspensory ligaments of penis, and some ligaments between vertebrae
allows stretching of various organs, strong and can recoil to its original shape after being stretched, important in normal functioning of lung tissue and elastic arteries



consists of a dense network of collagen fibers and elastic fibers firmly embedded in chondroitin sulphate, gel like component of gelatinous matrix; collagen and elastic fibers
can endure considerably more stress: tensile/resilence strength- collagen fibers, max strength that it can withstand while being pulled
avascular (heals slowly)
lacks nerves
covered by dense irregular connective tissue perichondrium (source of new cartilage cells)


Hyaline Cartilage

hyaline cartilage contains a resilient gel substance and appears in the body as a bluish-white, shiny substance, fine collagen fibers are not visible with ordinary staining techniques, surrounded by perichondrium (except articular cartilage in joints and epiphyseal plates)
most abundant cartilage in the body, end of long bones, anterior ends of ribs, nose, parts of larynx, trachea, bronchi, bronchi tubes, and embryonic and fetal skeleton
provides smooth surfaces for movement at joints, flexibility and support ; weakest of the three types and can be fractured


Elastic Cartilage

consists of chondrocytes located in a threadlike network of elastic fibers within the extracellular matrix; perichondrium is present
lid on top of larynx (epiglottis), part of external ear (auricle), and auditory tubes
provides strength and elasticity and maintains shape of certain structures



Chondrocytes are scattered among clearly visible thick bundles of collagen fibers within the extracellular matrix of fibrocartilage; lacks perichondrium
pubic symphysis, intervertebral discs, menisci (cartilage pads) of knee, and portions of tendons that insert into cartilage
support and joining structures together, strength and rigidity- tissue is the strongest of the three


Bone (Osseous) Tissue

store calcium and phosphorus, house red bone marrow and contains yellow bone marrow
contains osteocytes (mature bone cells) embedded in lacunae of a rigid, calcified matrix that includes collagen fibers


Compact (dense) Bone

composed of osteons (haversian systems) consisting of:
1. rings of matrix called lamellae which give bones compressive hardness and strength, and collagen fibers give tensile strength
2. Lacunae contain osteocytes
3. Canaliculi provides routes for nutrients and waste
4. central (haversain) canal contains blood vessels and nerves


Spongy (cancellous) Bone

lacks osteons, consists of bone called trabeculae, spaces between are filled with red bone marrow and yellow bone marrow


Blood Liquid Connective Tissue

extracellular matrix is called blood plasma, suspended in blood plasma:
1. Erythrocytes- transport the gases oxygen and carbon dioxide
2. Leukocytes- phagocytosis, immunity, and allergic reactions
3. Platelets- participate in blood clotting


Lymph Liquid Connective Tissue

extracellular fluid that flows in lymphatic vessels; interstitial fluid


Muscular Tissue

Consists of cells called muscle fibers (myocytes) that are specialized to contract and therefore provide motion, maintain posture, and generate heat


Skeletal Muscle Tissue

long, striated fibers (actin and myosin); muscle fibers can vary in length; multinucleated cell with nuclei located at the cell's periphery; voluntary movement
usually attached to bones by tendons
Motion, posture, heat production, and protection


Cardiac Muscle Tissue

branched and usually have only one centrally located nucleus; attach end to end by transverse thickenings of the plasma membrane called intercalated discs containing desmosomes and gap junctions (unique to cardiac muscle tissue) desmosomes strengthen the tissue and holf fibers together, gap junctions provide a route for quick conduction of electrical signals; involuntary control
heart wall
pumps blood to all parts of the body


Smooth Muscle Tissue

usually involuntary and lack striations (no light and dark bands); contains single, centrally located nucleus. gap junctions contain many individual fibers or contract individually when gap junctions are absent
iris of the eyes, walls of hollow internal structures such as, blood vessels, airways to the lungs, stomach, intestines, gallbladder, urinary bladder, and uterus
motion; constriction of blood vessels and airways, propulsion of foods through gastrointestinal tract, contraction of urinary bladder and gallbladder


Nervous Tissue

consists of neurons and nueroglia; little extracellular material is present



detect stimuli, convert stimuli into action potentials, and conduct these messages to other neurons, muscle fibers or glands; neurons consist of cell body, dendrites and axon



provide protection and support to the neurons; do not generate nerve impulses and outnumber neurons