vet-tech-a-p-1-ch-4-tissues

• cells of a similar type and function clustered into layers or sheets
• cells are like individuals - can complete individual job, but need to work together in tissues
• result of differentiation and specialization
• must cooperate with other cells for an organism to function

• divides readily in adults
• eg mucus mebranes, cornea, skin
• develops into carcinomas (cancer)
• composed of sheets or layers

• protects, lines and covers
• filters - kidneys
• absorbs
• senses
• secretes
• excretes

• responsible for excretion and secretion
• two types:
• - cellular - goblet cells - eg pseudostratified ciliated epithelium - individual drops of mucus
• - organ - pancreas

• leave the body
• "ex" like exit

• stay within the body
• "sec" like secret

• cells are tightly packed (shoulder to shoulder) to form sheets or layers
• polar - recognizable top and bottom
• adhere via junctional complexes
• avascular - no blood vessels - eg paper cuts that don't bleed
• innervated - lots of nerve endings

• three types:
• - tight junction
• - gap junction
• - desmosome
• space between cells contains a matrix that allows for nutrients to reach cell
• in any given type of epithelial tissues there can be more than one junction type (or all 3)
• - cardiac - desmosomes and gap junction
• determined genetically
• as you get older, ability to make junctions decreases, so old skin tears easily

• occlusive
• no leakage
• seen in:
• - bladder
• - GI tract

• needs 2 cells to link
• plaque or thickening
• extremely strong - like a weld
• mechanical - interlocking filaments
• filaments extend into the cell
• skin, heart, uterus - don't want cells to separate
• hemidesmosomes - basement membrane
• epithelial cell sends fibers into connective tissue & connects to fibers in there
• only one cytoplasmic plaque that acts like a washer

• transmembrane tubular proteins connect cytoplasm of one cell with the cytoplasm of the next cell
• proteins are called connexons
• intestinal, cardiac and smooth muscle
• virus and intraplasmic bacteria love these

• non-living mesh of fibers that cements the epithelial cell to the underlying connective tissue (the collagen in it)
• hemidesmosomes
• manufactured by the epithelial cells
• nutrients and waste diffuse across the basement membrane out of/in to connective tissue where blood vessels takes away/brings

• apical - from apex
• free border
• opens to space - lumen
• specialization
• - microvilli
• - cilia

• fingerlike projections increase the surface area
• brush border

• hairlike
• enables movement of material along cell surfaces

• number of cell layers:
• - one layer - simple
• - greater than one layer:
• -- stratified
• -- psuedostratified
• shape of cells:
• - squamous - flat
• - cuboidal - square
• - columnar - rectangular

• thin and delicate - so gases move right through
• line surfaces that exchange gas or liquid by diffusion/osmosis
• line thorax and abdomen
• - mesothelium
• -- mesothelioma - tumors of mesothelium
• line blood vessels
• - endothelium

• single layer of cuboidal cells
• secretory glands
• - endocrine
• -- thyroid
• - exocrine
• -- salivary
• -- pancreas

surface toward lumen

surface toward connective tissue

• elongated, closely packed cells
• nuclei located at base of cell
• associated with GI tract
• - absorptive cells
• - goblet cells are present
• excretory ducts - sometimes columnar in duct; cuboidal in secretory portion
• respiratory tract
• - ciliated
• e.g. hair - keratin produced in epithelial cells in scalp

• multiple layers of flat cells
• in areas of mechanical and/or chemical stress
• - mouth
• - vagina
• - rectum
• keratinized (on exterior) or not (on interior surface)
• cuboidal to squamous - basement is cuboidal, flatten as they move up

• "boutique tissue"
• 2 layers of cells (both cuboidal)
• lines large ducts of exocrine glands
• only 3 places in the body:
• - mammary - milk
• - sweat
• - salivary

• pseudo - false
• cells in a single layer
• - all are attached to basement membrane
• nuclei are staggered through compression
• - like a crowd that contains adults and children
• not all cells apical surfaces reach lumen
• ciliated
• in respiratory tree

• stretchy
• cells are rounded and dome like when relaxed, flattened and squamous when distended
• in bladder and other urinary structures

a single cell or group of cells that have the ability to manufacture and discharge a secretion

specialized protein molecules produced by the RER (rough ER) and packaged by the Golgi apparatus

• secretions are stored as granules within the cell
• eg histamine granules you can see in eosinophils with a microscope
• eg eosinophils secrete granules that let the rest of immune system know its under attack & needs to start working
• develop as invaginations of epithelium in the embryo
• the invaginations form ducts and tubules
• as the embryo develops, some of the ducts are lost and the gland becomes embedded in the deeper tissue

• presence or absence of ducts
• number of cells composing gland
• shape of the secreting ducts
• complexity of the glandular structure
• type of secretion
• manner of secretion

• endo - inside
• lack ducts
• produce hormones
• secrete directly into the blood
• part of a complex system
• the slow and steady part of the nervous system (but not really)

• makes melatonin
• helps adjust to seasons
• communicates with pituitary

inhibits/stimulates rest of endocrine system

tells you to start laying down fat in winter

• possesses ducts
• - classified by duct arrangement
• discharge secretions locally
• sweat, saliva, mucus, anal gland secretions are produced by exocrine glands
• pancreatic duct goes to small intestines to help digest food

benign tumor of gland

• simple, branched or compound
• tubular, coiled tubular or alveolar (grapelike)

• unicellular
• multicellular

• goblet cells
• modified columnar epithelial cell
• secrete
• - mucin - proteoglycans & glycoprotein that becomes mucus when contacts water

molecule that contains protein & sugar - more sugar than protein

molecule that contains protein & sugar - more protein than sugar

• composed of 2 components:
• - secretory unit
• - duct

• eg hot water heater makes hot water
• may be surrounded by myoepithelial cells to assist discharge of secretions

make actin & myosin fibers to allow contraction of glands

• eg pipes that carry hot water
• unbranched - simple
• branched - compound

• tubular - channel of even width
• acinar (alveolar) - rounded sac
• tubulaveolar (acinar) - qualities of both tubular and acinar

• merocrine
• apocrine
• holocrine

• secretion is released - secretory vesicle meshes with cell membrane
• cell remains intact
• sweat and saliva
• - percieve as H2O
• - no lipids, just protein

• apex of cell is lost during secretion - pinched off portion of cell contains secretion
• mammary and sweat (really sticky sweat)
• plasmalemma = fat in milk

• entire cell is destroyed upon release of secretion
• sebaceous glands
• - produce sebum (oil on skin), eg lanolin
• - sebaceous adenomas filled with cottage cheese like substance
• - eg ear wax

• serous
• mucus
• mixed

• watery
• enzyme rich
• generally merocrine solutions

• thick
• composed of glycoproteins

• eg tears
• contain both a mucus and serous component

• supports other tissues
• divides readily in adults
• develops into sarcomas
• - vaccine related sarcoma come from fibroblasts
• most abdundant tissue by weight
• most is derived from the mesoderm
• mainly composed of nonliving, extracellular matrix
• think of it as glue that holds the body together
• highly vascular
• doesn't mend itself like new if severed (like severed thread or rope)
• - never as strong as before
• - make mesh patch (synthetic) - sew on both sides of break - still not as strong

• extracellular fibers
• ground substance
• - ground as in background
• - different kinds
• - outside cells
• cells
• - fibroblast - young; makes fibers
• - mast cell macrophages - all connective tissue
• fibers and ground substance create matrix

• connective tissues vary in proportion of cells, fibers, matrix giving rise to a wide variety of morphologies
• - blood - ground subs=plasma, fiber=dissolved fibrin, cells= RBC & WBC
• - tendon - mostly collagen, not many cells, not much matrix
• - fat - adipose cells, fibers in between; cellulite is fibrous
• - bone (calcified) - cellular, calcified matrix

• provide metabolic and structural connections
• - tendon holds muscle to bone
• protection
• - bones protect soft organs
• - fat - soft tissue
• energy reserve - fat
• transport medium
• - blood - transport for all substances in body

• amorphous - blob-like
• homogenous
• - uniform throughout
• - liquid, semi-solid (gel) or calcified
• - glycoaminoglycans (GAGS)
• -- hyalauronic acid
• -- helps orient fibers correctly
• -- protien has nitrogen

• collagenous
• retivcular
• elastic

• most common
• strong and thick
• fibrils and microfibrils
• "white fibers"
• density and orientation determines function
• building block of all fibrous tissues
• think of collagen as a piece of monofilament (fibril)
• - put together, makes fiber
• - put more together, yarn
• - put more together, rope
• - within body, can find all sizes
• anabolic steroids damage collagen

• thin, delicate arrangements of collagen molecules
• under epithelium
• support highly cellular organs
• - hold up nephrons in kidney
• - blood vessels follow reticular fibers

• elastin
• - diff protein than collagen
• - like diff between thread and rubber band
• lack tensile strength
• - if you pull hard enough, it breaks
• eg earlobes
• eg horses - ligamentum nuchae
• - from skull to base of spine
• - holds head up
• - must use muscle to put head down
• eg arteries around the heart has these to allow blood flow
• - hardening of the arteries is loss of elasticity

• fixed
• transient (wandering)

• fibroblast
• fat (adipocytes)
• reticular

• secrete fibers and ground substance
• named by the tissue they are found in:
• - chondro - make cartilage
• - osteo - make bone
• blasts - actively producing
• cytes - mature cells that have stopped producing

• star shaped
• reticular fibers
• immune function

• move in and out of connective tissue
• leukocytes - neutrophils
• - diapedesis
• -- literally - walking across
• -- move out of connective tissue along reticular fibers using myosin & actin
• mast cells
• - histamines & heparin
• - inflammatory response
• macrophages
• - massive
• - fixed or transient
• - named based on tissue location (leftover from when we didn't know as much):
• -- Kupffer - liver
• -- microglial - brain
• -- histiocyte

• connective tissue proper
• specialized connective tissue

• categorized by how many fibers & their pattern
• dense connective tissue - numerous fibers
• loose connective tissue - fewer fibers

• dense regular - collagen
• dense irregular - collagen
• elastic - elastin

• collagen fibers are tightly packed and aligned in a parallel pattern
• relatively avascular
• little ground substance, so no slime factor
• tendons
• ligaments
• fascia

• collagen fibers are interwoven in thick bundles
• dermis
• organ capsules

• primary fibers are elastin, not collagen
• disks
• arteries
• bladder
• ligamentum nuchae

• areolar
• adipose
• reticular

• most common
• covers everything
• small open spaces
• cells - fibroblasts
• ground substance - hyaluronic acid (when peel skin off chicken, this is slimy, gel-like goo)
• fibers - all 3 types: reticular, collagen, elastin

• Fat
• little ground substance, few fibers
• adipocytes - cells
• - brown adipose tissue
• - white adipose tissue

• cell respiration - heat, not ATP
• hibernation and neonates - cannot thermoregulate

• torporous state
• when cold, shiver, brown fat produces heat, so don't need to wake up to exercise to get warm

• highly vascular
• energy store
• protection
• insulation - keeps you warm

• thin reticular fibers
• fibroblasts
• stroma
• - structure formed by connective tissue that other cells adhere to

• cartilage
• blood
• bone

• aka gristle
• more rigid than connective tissue proper
• avascular - perichondrium
• aneuronal - no nerve endings
• ends of long bone, nose, ear, vocal cords
• cells - chondroblasts (/cytes)
• - lacunae
• matrix:
• - hyaluronic acid
• - chondroitin sulfate
• - chondronectin
• fibers - collagen

• hyaline
• elastic
• fibrocartilage

• most common
• glass like - can't identify fibers in matrix
• covers ends of bones
• if damaged, is replaced by fibrocartialage
• supports trachea
• perichondrium
• - provides nutritional support
• - vascular

• fibers are coarser than hyaline cartilage
• junction of hyaline cartilage and dense regular connective tissue
• no perichondrium
• - menisci - in knee
• - disks - between vertebrae

• many elastic fibers
• epiglottis

• highly vascular
• osseous connective tissue
• organic - collagen
• inorganic - calcium salts
• osteocytes - mature
• osteoclasts
• - bone eaters
• - when you need calcium and don't get enough in diet
• periosteum

• cells
• - erythrocytes
• - leukocytes
• - platelets (pieces of thrombocytes)
• matrix
• - plasma - protein rich - particularly albumin
• fibers
• - fibrinogen - fibrin - transform under appropriate circumstances
• aspirin stops platelets from getting sticky
• - when platelets slow down they get sticky
• - blocked arteries can slow them down enough to make them sticky
• FIP - fluid pulled out full of fibrin
• hemorrhage - put pressure on for 5 minutes to allow form to clot

• intermediate step between tissues and organs
• connective tissue & epithelium working together
• - line body cavities - pleura & peritoneum
• - separate organs
• - cover surfaces
• -- frequently bathed in fluid
• --- urine - bladder
• --- mucus - lining of respiratory tree

• named for what they produce
• mucous
• serous - watery, eg pleural
• cutaneous - produce sebum, eg skin
• synovial - lines joints that move

• mucosae
• line organs that connect to the outside
• - bladder, intestines, respiratory tree, reproductive tract
• epithelial layer - stratified squamous or simple columnar (may be pseudo stratified)
• connective tissue - lamina propria - literally proper layer
• produce mucus
• animals can get sinus headaches, esp cats - when scruff can compress sinuses & hurt

• serosae
• cover organs and body cavities that don't open to exterior
• - parietal - attached to body wall
• - visceral - attached to organ
• simple squamous epithelium
• attached by loose areolar connective tissue
• produce transudate - thin & watery
• named for locaton:
• - pleural fluid
• - peritoneal fluid
• disease creates changes in membrane and fluid
• exudate
• - cells & protein added to transudate
• - check protein with refractometer
• effusion
• - ascites
• - leakage from membrane
• abdomino/thoracocentesis
• - ques is it transudate (tend to be acellular) or exudate

• special serous membrane
• thin material (web like) between blood vessels
• - keeps them fanned out
• - can twist & intestine will die
• stomach mesentery called omentum
• mesentery is continuous with peritoneum
• peritoneal space has organs covered with visceral peritoneum
• blood vessels originate from aorta along spine
• cranial & caudal mesenteric arteries branch to different pieces of intestine

• integument - skin
• keratinized stratified squamous epithelium (epidermis - on top of dermis)
• dermis - connective tissue that supports epidermis

• lines the cavities of freely moveable joints
• no epithelium - this makes it unique
• only has connective tissue
• loose connective tissue covered bu adipose tissue and a layer of collagen and fibroblasts
• swollen joint has too much synovial fluid
• - highly proteinaceous, no cells normally

• prefix = myo
• composed of cells called fibers (gross description, not same as fibrous connective tissue)
• cells contain filaments (little threads) composed of actin & myosin
• 3 types:
• - skeletal
• - smooth
• - cardiac

• long, large, multinucleate cells
• voluntary - controlled through concious thought
• striated
• associated with nerves
• - paresis - weakening of muscle
• - paralysis - loss of function
• shortens when it contracts
• every muscle fiber has an axon terminal to allow range of motion from small to large
• - touching someone vs punching them

• weakening of muscle
• hard to assess in animals
• - sled dogs that can't pull as much as they used to
• - draft horses can't do as much work as they used to

• small, spindle shaped cells
• no striations
• walls of hollow organs and blood vessels
• nonstraiated, involuntary muscle
• still have actin & myosin
• scrunches when contracts

• found only in the heart
• myocardium
• involuntarty, striated
• branched
• intercalated disks (junctures)
• think of it as joint in water pipe - bolted together, but hollow so water can flow
• cells all communicate so heart beats together

• neurons & neuroglial cells
• transmit & recieve electrical impulses

• perikaryon (cell body)
• dendrites
• axons

• connective tissue
• most numerous cells in the neural tissue
• highly specialized
• - astrocytes - blood-brain barrier
• - oligodendrocytes - myelin sheath
• - microglia - phagocytosis - basically macrophages
• - ependymal - CSF (cerebrospinal fluid)
• small cells around large motor neurons