Chapter 3 Tissues

types of tissues

• epithelial

• muscle

• neuro

• connective

epithelia

sheet of cells that cover every exposed body surface and line internal cavities and passageways

characteristics of epithelia

• cellularity: little to no intercellular space between cells

• polarity: apical and basal surfaces

• attachment: basement membrane anchors

• avascularity: no blood vessels present

• sheets

• regeneration

which types of tissue are avascular?

Epithelial and cartilage

which types of tissue are innervated?

nervous

what type of tissue are gland cells? what do they do

epithelial which produce secretionsun

unicellular glands

individual gland cells scattered among other cell types in an epithelium

grandular epithelia

most or all epithelial cells produce secretions

superficial portion of basement membrane

basal lamina

which region of basement membrane is dominated by glycoproteins, proteoglycans, and microfilaments

basal lamina

deep to basal lamina and second level of basement membrane

reticular lamina

what tissue secretes reticular lamina

connective tissue

simple epithelium

A single layer of cells that forms a protective barrier for underlying tissues and is involved in absorption, secretion, and filtration.

stratified epithelium

multiple layers of cells

squamous epithelium

thin flat irregular shaped cells

simple squamous

found in protected delicate areas that are slippery

stratified squamous epithelium

used where mechanical stress is severe

• keratinized

• nonkeratinized

nonkeratinized stratified squamous

lines mucosal cavities

keritinized stratified squamous epithelium

areas of protection like the skin

simple cuboidal epithelium

protection near regions of secretion and absorption - ex: kidneys

stratified cuboidal

rare and found in sweat and mammary glands

simple columnar epithelium

absorption and secretion occurs - stomach

stratified columnar epithelia

rare, occur in pharynx urethra and anus, excretory ducts

rarest types of epithelia

stratified cuboidal and stratified columnar

pseudostratified

nasal cavity

transitional epithelium

stratified and can stretch w/o damage. ex: bladder - luffy is probably made entirely of this

three types of exocrine glands

• serous: secrete watery solution

• mucous: secrete sticky solution

• mixed: both

endocrine glands

secrete hormones inside of body

2 types of unicellular glands

• mucous cells

• goblet cells

simplest multicellular gland

secretory sheet

does the duct of a simple exocrine gland branch

no, but they do for compound exocrine glands

3 methods of secretion

• eccrine/merocrine

• apocrine

• holocrine

eccrine/merocrine glandular secretion

vesicles

apocrine glandular secretion

shedding

holocrine glandular secretion

cell destroys itself

basic components of connective tissues

• specialized cells

• extracellular protein fibers

• ground substance

functions of connective tissue

• establish structural framework

• transport fluids

• protect delicate organs

• support

• energy storage

• defense from invaders

types of connective tissue

• connective tissue proper

• fluid connective tissue

• supporting connective tissue

2 parts of connective tissue

• extracellular matrix

• ground substance

fixed cells

involved with local maintanence repair and energy storage

fixed mesenchymal

fixed, stem cells that can differentiate into various cell types.

fixed fibroblasts

one of the two most abundant fixed cells, produce all connective tissue fibers and secrete hyaluron

fixed fibrocytes

differentiate from fibroblasts and are the second most abundant

• responsible for maintaining dense layer of basement membrane when epithelial tissue covers a layer of areolar tissue

fixed macrophages

engulf damaged cells and defend body

fixed adipocytes

lipid droplets

fixed melanocytes

store brown pigment

wandering cells

help defend and repair damaged tissues

free macrophages

large phagocytic cells that go around engulfing pathogens

• when circulating in blood, called monocytes

free mast cells

sacs of histamine and heparin released after injury/infection - inflammation

free lymphocytes

migrate throughout body and multiply wherever tissue is damaged. turn into plasma cells and produce antibodies

free neutrophils/eosinophils

phagocytic blood cells that are smaller than monocytes. mast cells attract neutrophis when infection/injury occurs

fibers of connective tissue

collagen, reticular, and elastic fibers

collagen fibers

long, straight, and unbranched. its three fibers braided together like a rope whcih is good when tension is applied. gives it tensile strength

tendons

muscle to bone - parallel alignment of collagen fibers allows them to withstand tremendous force

ligaments

bone to bone, bone to cartilage, cartilage to cartilage

reticular fibers

network of protein subunits that are interwoven framework - tough, but flexibile,

elastic fibers

elastin can stretch up to 150 percent of resting length

ground substance

surround cellular and fibrous components of connective tissue

• clear colorless maple syrup consistancy

loose connective tissue

packing peanuts of the body provide cusion and support epithelia while allowing flexibility and movement.

areolar tissue

least specialized connective tissue. contains all tissues found in connective proper. ground substance accounts for most of it’s volume

• can be distorted wo damage

epithelial tissue consists almost entirely of ______

cells

connective tissue consists mostly of _______

extracellular matrix

types of connective tissue proper

• loose 

• dense

types of fluid connective tissue

• blood

• lymph

types of supporting connective tissue

• cartilage

• bone

types of loose connective tissue

• areolar 

• adipose

• reticular

types of cartilage

• hyaline

• elastic

• fibrous

what separates skin from deeper tissue

a layer of areolar tissue

drugs injected into the ______ are quickly absorbed into blood

areolar tissue

are adipocytes found in almost all alreolar connective tissues

yes

two types of adipose tissue

white fat and brown fat

white fat

more common in adults, pale yellow white color. adipocytes contain single large lipid droplet and are unilocular adipose cells. cusion shock, slow heat losee, packing peanuts

brown fat

infants and children, fat is stored in cytoplasmic vacuoles in brown adipose cells (multilocular adipose cells) - highly vascularized and a lot of mitochondria, good for heat generation

reticular tissue

consists of reticular fibers, macrophages, fibroblasts, and fibrocutes, good framework for support of liver, spleen, lymph nodes, and bone marrow

dense connective tissue (collagenous) and two types of it

most volume is from fibers, mostly collagen. dense regular and dense irregular

dense regular connective tissue

collagen fibers are packed tightly togethered and aligned parallel to applied forces. ex: tendons, ligaments, elastic tissue, aponeuroses

tendons

dense regular connective tissue attach muscle to bones and cartilage

aponeuroses

dense regular connective tissue - collagenous sheets that resemble flat broad tendons, help attach superficial muscles to another muscle or structure

elastic tissue

dense regular connective tissue - lots of elastic fibers make it springy and resilient

ligaments

dense regular connective tissue - connect cartilage to cartilage, bone to cartilage, or bone to bone. lots of elastic and collagen fibers 

elastic ligaments

higher proportion of elastic fibers than ligaments alone. a type of dense connective tissue regular

dense irregular connective tissue

interwoven meshwork of randomness, tissue strengthens and supports from many directions. forms sheath around cartilage (perichondrium) and bone (perosteum) except in joints. also forms thick fibrous capsule surrounding many internal organs and cavities

do tendons and ligaments both contain fibrocytes

yes, both tendons and ligaments contain fibrocytes, which are cells responsible for maintaining the extracellular matrix and collagen fibers.

difference between tendons and elastic ligaments

tendons

• relatively few fibrocytes

• fibrocytes are located between bundles of collagen fibers

• fibrocytes tend to be elongated

ligaments

• fibrocytes are more numerous

• fibrocytes are found among bundles of collagen fibers

• fibrocytes tend to be less elongate

types of fluid connective tissues

blood and lymph

rbc account for ___ the volume of blood

1/2

the subdivisions of extracellular fluid of fluid connective tissue

• plasma

• interstitial fluid

• lymph

cartilage and bone are __________ that provide strong framework to support the rest of the body

supporting connective tissues

cartilage matrix

firm gel, contains complex polysaccharides (chondroitin sulfates) which form proteoglycans

what are teh only cells within the cartilage matrix?

chondrocytes/cartilage cells

where do chondrocytes live

lacunae (c for cave)

is cartilage avascular? why or why not?

no, bc chondrocytes produce a chemical that discourages formation of blood vessels

perichondrium

where nutrients diffuse into and waste diffuses out of cartilage

2 layers of perichondrium

fibrous layer and inner cellular layer

what is in the fibrous layer of the perichondrium

dense irregular connective tissue

methods of cartilage growth

appositional and interstitial

appositional growth

stem cells form inner layer of perichondrium undergo repeated cell division and differentiate into chondroblasts which produce cartilage matrix. these chondroblasts mature into chondrocytes. the width increases 

interstitial growth

chondrocytes within cartilage matrix divide and daughter cells produce additional matrix. enlarges cartilage from within like a balloon inflating. grows in length

hyaline cartilage

most common, matrix conntains closely packed collagen fibers

elastic cartilage

elastic fibers make it flexible and resilient, allowing it to withstand repeated bending. Found in structures like the external ear and epiglottis.