A&P 7

• epithelial
• connective
• muscular
• nervous

• inestinal tract has one
• describing the part that light would shine through or the "empty space"
• there is an epithelium covering this lumen, because the lumen is part of the outside (non-body) world

• 1 free surface (apical surface)
• 1 surface attached to basement membrane (basal lamina & reticular lamina)
• underlying connective tissue
• locations: 1. barriers to keep outside out & inside in, 2. barriers that secrete substances, & 3. barriers for protection

top that faces the outside world

base, basement that rests on & is attached to basement membrane

consists of 2 thn layers, each called a lamia (basal & reticular lamina)

nearest of the epithelial cells

bit deeper than basal lamina

• SIMPLE- cells are a single layer, all in contact w/ basement membrane
• PSUEDOSTRATIFIED- cells appear to have layers, every one is in contact w/ basement membrane
• STRATIFIED- cells have layers, only lowest layer is in contact w/ basement membrane

• SQUAMOUS- cells are flat & shaped like fish scales, are wider than are tall
• CUBOIDAL- cells are as wide as they are tall, like little rice cubes
• COLUMNAR- cells like a column, taller than they are wide

• 3 arrangements X 3 shapes= 9 combos
• 2 of these not used, but add transitional (cells thta change shape= 8 combos)
• if different shapes present, ALWAYS NAMED BY SHAPE OF CELLS IN APICAL (outermost) LAYER

• single layer of thin & flat cells
• used where substances need to diffuse across the epithelium, or where filtration is taking place
• locations: lining of heart, blood, & lymph vessels- air sacs of lungs- kidney filtration- eardrum- one layer of serous membranes

• single layer of cube-shaped cells
• often found where secretion or absorption is taking place, as in glandular tissue
• locations: surface of ovaries, eye (anterior surface of lens & pigmented epithelium), kidney tubules, & many glands

• single layer of column-like cells
• w/ or w/out cilia
• w/ or w/out microvilli (increase surface area)
• w/ or w/out mucus (goblet cells)
• 2 subtypes: 1. ciliated (cilia on apical surface) moves mucus & substances trapped in mucus by wave-like motion of cilia (locations: respiratory tract, uterine tubes/uterus, efferent ducts testes, some paranasal sinuses, & canal of spinal cord & ventricles of brain 2. nonciliated- used ofr secretion or absorption (locations: GI tract, glandular ducts, & gallbladder)

• it is unusual
• appears to have layers, it doesn't
• all cells attached to basement membrane
• "pseudo"- lying, false
• locations: ciliated- upper respiratory airways, non-ciliated- glands, epididymis& urethra

mucus producing cells

mucus cells secrete mucus to trap dust & invaders, so they can be moved up to the throat

• most common type of epithelium in human body
• apical surface is made up of squamous (flat) cells
• other layers have diff shapes, but named based on apical layer
• location: skin & mucous membranes

• apical surface is made up of cube-shaped cells
• 2 or more layers
• location: sweat gland ducts, esophageal gland ducts, & part of male urethra
• involved in secretion

• apical surface is made up of tall cells (taller than they are wide)
• 2 or more layers
• locations: part of (lining of) urethra, excretory ducts of some glands, part of anal mucous membranes, & part of conjunctiva in eye

• shape of cells changes depending on state of stretch
• several layers
• location: bladder & nearby urethra/ ureters
• full bladder: squamous cells
• empty bladder: cuboidal cells

• endocrine glands secrete substances into extracellular fluid then blood (hormones)
• exocrine glands secrete substances outside of body (duct)
• both generally lined w/ (simple or stratified) cuboidal epithelium

production of substances that are released outside the body (exocrine glands) or w/in the body (endocrine glands)

substances that alter the metabolism or function of body cells

glands named based on: branching pattern of duct(purple)- unbranched=simple or branched=compound & shape of secretory portion(pink)- tube-like=tubular, grape-like=acinar, or both=tubuloacinar

• simple tubular
• simple branched tubular
• simple coiled tubular
• simple acinar
• simple branched acinar
• compound tubular
• compound acinar
• compound tubuloacinar

• sweat
• most common: eccrine "watery"/ mucin mixes w/ water to form mucus
• steps in formation of secretory product: 1.DNA instructions transcribed to mRNA in nucleus, 2.synthesized in RER, 3.packaged in Golgi complex, 4. formed into secretory vesicle, 5.released - exocytosis
• doesn't damage cell
• they're everywhere, except for where you have hair

• part of milk production/ prostate gland
• steps in formation of secretory product: 1.DNA instructions transcribed to mRNA in nucleus, 2.synthesized in RER, 3.packaged in Golgi complex, 4.formed into vesicle, 5.end of cell breaks off & dissolves

• sebaceous glands of the hair follicles/ glands of the eyelids
• steps in formation of secretory product: 1.DNA instructions transcribed to mRNA in nucleus, 2.synthesized in RER, 3.packaged in Golgi complex, 4a. cell dies, releasing product, 4b.lost cell replaced by division of stem cells
• destroys the cell

• connects epithelium to the rest of the body
• it's made up of 3 parts: ground substance (extracellular matrix), fibers (collagen, elastic, & reticular fibers), & cells

• aka extracellular matrix
• several important proteins found here: fibronectin(adhesion), laminin(cell differentiation), & proteoglycans(class of proteins that contain lots of sugar, for ex-mucus is mostly proteoglycan)
• integrin links these to cell surface
• collagen fibers link these to connective tissue

• 1. collagen fibers- made up of collagen(naturally), comes in several diff types that vary between tissues(called type I collagen....all the way up to type XXIX collagen)
• it's a triple helix, which gives it strength along the fiber
• 2. elastic fibers- made up of elastin, are abundant in tissues that need to stretch & then snap back into their previous shape, like blood vessels
• 3. reticular fibers- made up of type III collagen
• originally named separately because their silve staining properties, but later proved that reticular fibers are a type of collagen fiber

• 1. fibroblasts- most numerous cell, secrete fibrous components & ground substance, they lay down protein fibers (collagen, elastin, reticular fibers)
• 2. adipocytes- (big yellow cells) fat cells, store triglycerides, insulation, energy storage
• 3. mast cells- (all over the body) near blood vessels, important in inflammation; produce histamine
• 4. white blood cells- (part of immune system) migrate to sites of damage (neutrophils, eosinophils)
• 5. macrophages- "big eaters": swallow & destroy invaders or debris, fixed or wandering
• 6. plasma cells- formed from white blood cells (B lymphocytes), secrete special proteins called antibodies that help attack invaders

• cells that defend the body against invaders
• they patrol the connective tissues & attack any enemies they find there
• cells in this group include: mast cells, white blood cells, macrophages, & plasma cells

• in the embryo, rapidly dividing cells are gathering together into organs and tissues, so they must be able to move freely
• in a mature human, by contrast, the job of connective tissue is to hold things in place, & it generally does not want to allow movement of cells

• almost all of the embryo is made up of this
• it's almost fluid in consistency and the cells are widely spaced

jelly-like connective tissue in the umbilical cord of the embryo, connecting the mother & child

• 1. mesenchyme
• 2. mucous connective tissue (wharton's jelly)

• 1. loose connective tissue
• 2. dense connective tissue
• 3. cartilage
• 4. bone
• 5. liquid

• subcategories include:
• areolar connective tissue; adipose tissue; and reticular connective tissue

• most common connective tissue type
• found in a wide variety of locations (in layer supporting the skin & mucous membranes, & supporting surrounding organs)
• consists of a mixture of fiber types (collagen, elastin, & reticular fibers) & cell types (fibroblasts & defense cells)

• found under the skin, around heart & kidneys, in yellow bone marrow, & forming a cushion in joints & surround the eye socket
• consists of cells calle adipocytes (have huge fat droplet surrounded by a rim of cytoplasm & nucleus)

• reticular fibers in a loose meshwork w/ reticular cells
• forms the stroma (supporting framework) of the liver, spleen, lymph nodes, & red bone marrow (where blood cells are formed)
• also forms reticular lamina of the basement membrane

subcategories include: dense regular; dense irregular; & elastic

• appears grossly as a white, shiny sheet
• made up of collagen fibers in regular bundels w/ a few fibroblasts
• it's found in tendons(which connects muscle to bone); in ligaments (connects bone to bone); & sheetlike tendons called aponeuroses
• dense structure w/ lack of blood supply, which makes tissues extremely slow to heal after injury

• has fibroblasts & collagen fibers, but the collagen fibers run in many diff directions- this gives the strength in all directions
• found in the fasciae, which form sheets b/n muscles; in the deeper part of the skin; in the "peri-" tissues that surround bone, cartilage & the heart

• made up of many oriented elastic fibers (like little bungee cords) & a few scattered fibroblasts
• found in the lungs, trachea, bronchial tubes, & vocal cords; in walls of arteries; in ligaments b/n vertebrae; & in suspensory ligaments of the penis

• 1. hyaline
• 2. fibrocartilage
• 3. elastic cartilage
• cartilage is harder and less flexible than dense connective tissues

• living part of hyaline, fibrocartilage, & elastic cartilage
• cell that looks like a fried egg through the microscope

• most abundant type of cartilage
• shiny, bluish-white substance
• consists of fine collagen fibers & many chondrocytes

encloses chondrocytes

• has a more fibrous appearance
• collagen fibers are coarser & gathered together into thick bundles
• found in the pubic symphysis (where the bones of the pelvis are joined), in the discs b/n vertebrae, in padding of knees (menisci), & where tendon inserts into cartilage

• makes up the flap- sorts out liquid from air in the throat (epiglottis), in the external ear, & in tubes that connect ear to mouth that "pop" when pressure changes (auditory tubes or Eustachian tubes)
• made up of meshwork of elastic fibers surrounding the chondrocytes

• 1. compac bone
• 2. spongy bone

cells of the bone

has complex & regular structure consisting of osteons as the basic functional & anatomical unit

• has a much more irregular structure
• spikes of mineralized tissue have ample space b/n for red bone marrow

• 1. blood (red blood cells(erythrocytes), white blood cells(leukocytes), & platelets(thrombocytes)) red & white are cells, platelets are cell fragments- these components are COLLECTIVELY called formed elements, a thick liquid connective tissue matrix-plasma(primarily salt water plus proteins) surrounds these formed elements
• 2. lymph- a filtrate of blood w/ most of the cells & some of the protein removed- white blood cells move around in the lymph to guard against invaders

• tight junctions
• adherens junctions
• desmosomes
• hemidesmosome
• gap junctions

• problem: need to link cytoskeleton of adjacent cells to each other
• or, need to link cytoskeleton to the extracellular matrix
• cell junctions perform this function (tight, adherens, desmosomes, hemidesmosomes, & gap junctions)

• "ziplock bags" of tissue world
• found where a tight, leakproof seal is needed (b/n 2 or more cells where substances cannot be allowed to percolate b/n cells)
• ex: stomach, intestines, urinary bladder: keep material from leaking out of these organs

• use a protein call cadherin (glycoprotein that holds these together)
• adhesion belt, like the belt on your pants, keeps tissues from separating as they stretch & contract

• used as "spot welds" to hold tissue together against mechanical disruption b/n 2 cells
• also use cadherin b/n the cells, plus intermediate filaments hooking it to cytoskeleton

• 1/2 a desmosomes
• these are found NOT b/n 2 cells, but rather b/n a cell & its basement membrane
• a protein called integrin is used to link the hemidesmosome to the basement membrane
• here, spot weld joins cell to the basement membrane

• serves an electrical & biochemical link b/n 2 cells (in contrast to mechanical links)
• pores (connexons (formed from protein, connexin)) allow substances <1000Da to pass b/n cells
• calcium and other small, hydrophilic ions can pass through the channel formed by connexons
• cells are electrically coupled
• if one of the cells gets sick or dies, then [Ca⁺⁺] increases & these seal like a hatch

• epithelium + connective tissue= epithelial membrane
• called epithelial membranes because of the overlying layer of epithelium, mucous, serous, & cutaneous membranes all have a layer of epithelium w/ an underlying areolar connective tissue
• 3 epithelial membranes are:
• mucous membrane- line exterior surfaces of body- digestive, respiratory, & reproductive tract
• serous membrane- parietal layer(next to body wall), serous fluid b/n, & visceral layer(next to organ)
• cutaneous membrane (integument or skin)

epithelial & synovial membranes

connective tissue layer of mucous membranes

• synovial membranes= connective tissue only
• line the space b/n 2 bones forming a joint
• found only @ joints(where 2 bones come together)
• connective tissue secretes synovial fluid, which lubricates the joint

• present wherever body needs to generate force, it moves body, maintains posture, & generates heat
• each kind of muscle tissue uses 2 cytoskeletal proteins to generate heat- myosin & actin
• there are 3 main types of muscle tissue: skeletal, cardiac, & smooth

• aka voluntary muscle, we "choose" to use it
• it's a type of striated muscle, it appears to be striped/striated (when looking @ it under microscope)
• made up of muscle cells that have fused to form a long, thin tube (or myofiber called syncytium("joined cells")), w/ multiple nuclei visible on the outside of the muscle fiber

• also has a striated appearance, but not generally thought of as under voluntary control
• fibers are joinded in branches, rather than running parallel to each other (as they do in skeletal muscle)
• 1 or 2 nuclei per fiber instead of dozens

• NOT under voluntary control (ex: gut tube is lined w/ smooth muscle that keeps digestion proceeding from mouth to anus)
• single cells, each w/ 1 nucleus, & cytoskeleton is arranged in a random fashion so that it doesn't have a striated appearance

• manipulates info
• only tissue in body that can manipulate electrical charges to receive, process, & transmit info
• *muscle cells manipulate charges, but contract & don't send info
• *all other tissues have electrical charges, but most can't control them
• 2 main cell types: neurons (info processing) & glial cells (support & maintenance)

• muscle & nerve tissue together
• by manipulating the flow of electrical charge, they can produce action potentials & other unique electrical events inside the cell