MCB 244 Exam 2

simple squamous function

thinnest barrier that allows rapid diffusion and filtration; secretion in serous membranes

simple squamous location

lining of lung air sacs (alveoli), blood and lymph vessel walls (endothelium), serous membranes of body cavities (mesothelium)

simple cuboidal functions

absorption and secretion (ideal as structural components of glands and small ducts)

simple cuboidal location

lining of kidney tubules, thyroid gland follicles, surface of ovaries, secretory regions and ducts of most exocrine glands

non-ciliated simple columnar function

absorption and secretion

non-ciliated simple columnar location

lining of most of digestive tract from stomach to anal canal

ciliated simple columnar function

secretion of mucin and mucus movement; oocyte movement through uterine tube

ciliated simple columnar location

lining of bronchioles in the lung and uterine tube

has goblet cells

non-ciliated simple columnar

does not have goblet cells

ciliated simple columnar

ciliated pseudostratified columnar function

protection, secretion of mucin, movement of mucus along the epithelial surface by cilia

ciliated pseudostratified columnar location

large passageways of respiratory system (nasal cavity, parts of pharynx, larynx, trachea, and bronchi)

has goblet cells

ciliated pseudostratified columnar

does not have goblet cells

non-ciliated pseudostratified

non-ciliated pseudostratified columnar function

protection

non-ciliated pseudostratified columnar location

rare, found mainly in male urethra and epididymis

keratinized stratified squamous function

protection of underlying tissue from abrasion

keratinized stratified squamous location

epidermis of the skin

non-keratinized stratified squamous function

protection of underlying tissue from abrasion

non-keratinized stratified squamous location

lining of oral cavity, part of pharynx, esophagus, vagina, anus

stratified cuboidal function

protection and secretion

stratified cuboidal location

sqeat glands, parts of male urethra, periphery of ovarian follicles

stratified columnar function

protection and secretion

stratified columnar location

large ducts of salivary glands, conjunctiva of the eye, parts of male urethra

transitional epithelium function

allows for stretching as bladder fills

transitional epithelium function

allows for stretching as bladder fills

transitional epithelium location

limited to urinary tract (bladder, ureters, and parts of urethra)

glands

individual cells or multicellular organs composed of epithelial tissue

endocrine glands

lack ducts; secrete hormones into blood

exocrine glands

connected with epithelial surface by duct (an epithelium-lined tube for gland secretion), invaginated epithelium in connective tissue

exocrine gland examples

sweat glands, mammary glands, salivary glands

unicellular exocrine glands

do not contain a duct, located close to epithelium surface, ex: goblet cell

multicellular exocrine glands

numerous cells, ducts transport secretions to epithelial surface, surrounded by a fibrous capsule, extensions of which may form septa, partitioning a gland into lobes

acini

cell clusters that produce secretions

simple glands

a single, unbranched duct

compound glands

branched ducts

tubular glands

secretory portion and duct same diameter

acinar glands

secretory portion forms expanded sac

tubuloacinar gland

both tubules and acini

merocrine glands

package secretions into vesicles, released by exocytosis

merocrine glands examples

lacrimal (tear) & salivary glands

apocrine glands

apical membrane pinches off and becomes secretion

apocrine glands examples

mammary and ceruminous glands

holocrine glands

ruptured cell becomes secretion

holocrine glands examples

sebaceous (oil) glands

wandering cells

continuously move through CT, components of immune system, repair damaged extracellular matrix, types of leukocytes (white blood cells), protect body from harmful agents

resident cells

stationary, housed in CT; support, maintain, repair extracellular matrix, ex: fibroblasts, adipocytes, macrophages

fibroblasts

flat cells with tapered ends, most abundant resident cells in CT proper, produce fibers and ground substance of ECm

adipocytes

appear in small clusters in some types of CT proper, dominant area of large clusters

mesenchymal cells

embryonic stem cell, divides to replace damaged cells, one replaces mesenchymal cell and other becomes committed cell

fixed macrophages

relatively large irregular-shaped cells, derived from monocytes (a type of leukocyte), dispersed throughout matrix, phagocytize (engulf) damaged cells or pathogens, release chemicals to stimulate immune system/attract wandering cells

collagen fibers

unbranched, “cable-like” long fibers (white glistening appearance), numerous in tendons and ligaments

reticular fibers

similar to collagen fibers but thinner, abundant in stroma of some organs

elastic fibers

contain protein elastin (thinner than collagen), usually coated with the glycoprotein Fibrillin, stretch and recoil easily, found in skin and walls of arteries

ground substance

molecular (not cellular) material produced by CT cells; residence for CT cells and protein fibers; consistency: viscous, semisolid, solid; absorbs compression forces and protects delicate cells from injury

glycosaminoglycans (GAGs)

large molecule in ground substance (chondroitin, sulfate, heparin, hyaluronic acid); charge attracts cations, water follows

proteoglycans

formed with GAG linked to a protein; form thick colloids

glycoproteins

proteins with carbohydrates attached; bond CT cells and fibers to ground substance

mesenchyme function

source of all other connective tissue cells

mesenchyme location

throughout the body of the embryo and fetus

mucous function

support of structures in umbilical cord

mucous location

umbilical cord of fetus

connective tissue proper: loose CT

fewer cells and protein fibers than dense CT, protein fibers are sparse and irregularly arranged, abundant ground substance, body’s “packing” material, supports structures

areolar CT description

loose organization of collagen, highly vascularized (many blood vessels), predominant cells are fibroblasts within abundant and viscous ground substance

areolar CT function

protection of tissues and organs; binding skin and some epithelia to deeper tissue; providing space for blood vessels and nerves

areolar CT location

the papillary layer of dermis, subcutaneous layer, and surrounding organs, nerve and muscle cells, and blood vessels

adipose CT description

commonly referred to as fat, composed closely packed adipocytes; nucleus pushed to the edge of the cell by large fat droplet, highly vascularized (many blood vessels)

white adipose CT

stores energy, acts as insulator, cushions

brown adipose CT

found in newborns, generates heat, lost as we age

adipose CT function

energy storage; insulation/cushioning; protection

adipose CT location

subcutaneous layer; covers some organs

reticular CT description

meshwork of reticular fibers, fibroblasts, leukocytes within a viscous ground substance

reticular CT function

providing structural framework (stroma) for many lymphatic organs

reticular CT location

spleen, thymus, lymph nodes, and red bone marrow

connective tissue proper: dense ET

mostly protein fibers, less ground substance than loose CT, collagen fibers predominate

dense regular CT description

fibroblasts squeezed between densely packed, parallel collagen fibers, stress typically applied in a single direction, few blood vessels and limited ground substance, takes a long time to heal

dense regular CT function

attach muscle to bone or bone to bone; resists pressure applied in one direction

dense regular CT location

tendons (attach muscle to bone) and ligaments (attach bone to bone)

dense irregular CT description

fibroblasts between densely packed, randomly arranged clumps of collagen fibers; extensive blood vessels, more ground substance than in dense regular CT

dense irregular CT function

provides support and resistance to stress in multiple directions; durability

dense irregular CT location

reticular layer of dermis, periosteum of bone, perichondrium of cartilage, capsules around internal organs; epimysium of muscle

elastic CT description

limited fibroblasts between branching and densely packed elastic fibers

elastic CT function

allows stretching and recoil

elastic CT location

walls of large arteries, trachea, vocal cords

supporting CT: cartilage

firm, semisolid ECM, collagen and elastic protein fibers, strong and resilient, more flexible in bone, in areas of body that need support and must withstand deformation, avascular in mature state

chondrocytes

mature cells that occupy small spaces called lacunae

hyaline cartilage description

irregularly arranged chondrocytes in lacunae, surrounded by clear, glassy ground substance (perichondrium)

hyaline cartilage function

provides support, forms most of fetal skeleton

hyaline cartilage location

nose, trachea, and larynx, costal cartilage, articular ends of long bones, most of fetal skeleton

fibrocartilage description

large chondrocytes in lacunae; numerous, parallel collagen fibers in irregular bundles, sparse ground substance; no perichondrium

fibrocartilage function

weight-bearing cartilage, resists compression

fibrocartilage location

intervertebral discs, pubic symphysis, menisci of knee joint

elastic cartilage description

flexible, springy cartilage, closely packed chondrocytes in lacunae, numerous densely packed elastic fibers that form weblike mesh, limited ground substance; cells surrounded by perichondrium

elastic cartilage function

ensuring that tissue is resilient and flexible while maintaining shape

elastic cartilage location

external ear and epiglottis

supporting CT: bone

more solid than cartilage, greater support but less flexible, organic components (collagen and glycoproteins), inorganic components (calcium salts), made of bone cells (osteocytes), housed within spaces in ECM called lacunae

compact bone

perforated by neurovascular canals, organized in cylindrical structures called osteons (concentric lamellae arranged around a central canal), display concentric rings of bone CT called lamellae; encircle central canal, location of blood vessels and nerves

spongy bone

located in interior of bone, latticework structure, strong and lightweight

structure of bone tissue

osteocytes within lacunae entrapped in calcified (hard) ECM which contains protein (primarily collagen) fibers, and ground substance; both compact and spongy types well vascularized

bone functions

levers for movement, support tissues, protects vital organs, stores minerals like calcium and phosphorus, houses hematopoietic cells which make blood cells