Module 1 Cheat Sheet

Module 1: Introduction∙Tissue: organized group of cells woven together to perform a specific function (texo is L atin for “to weave”) o The basic tissues are blood, connective tissue, epithelial tissue, muscle, nervous tissue ▪Blood: composed of plasma and cells∙Plasma: complex fluid▪Connective Tissue: supports 3 other basic tissue, composed of cells and a matrix∙The matrix fluid is what gives the connective tissue its characteristics▪Epithelial Tissue: covers body surface and lines body cavities▪Muscle: muscle tissue contracts via the highly organized contractile proteins actin and myosin to produce movement in an entire organ▪Nervous Tissue: receives, integrates and transmits information∙Organ: formed by the assembly in similar ways of tissue functional units∙Basics: tissue preserved in formalin, dehydrated, embedded in paraffin wax and cuto Color from stain: hematoxylin is dark blue/purple, eosin is pink▪Stains highlight specific featureso Intracellular is 60% of total body water or 40% of body weighto Extracellular is 40% of total body water or 20% of body weight▪Interstitial fluid: 30% of total body water▪Plasma: 8% of total body water▪Transcellular fluid: 2% of total body water∙Sodium is the most abundant electrolyte∙Osmolarity of intracellular fluid and extracellular fluid should be identicalo If not, water moves from low osmolarity to high osmolarity∙Homeostasis: the maintenance of nearly constant conditions in the internal environment regarding the control of vital parameters, maintained by positive and negative feedbacko Equilibrium of:▪Bodily functions▪Chemical compositionso Senses the parameter using sensor/receptor (requires a stimulus)o Compares the parameter to normal operating valueo Sensor produces an output signal to a control center▪Example: raised blood pressure∙Inhibitory interneurons to the sympathetic centero Sympathetic inhibition decreases blood pressure∙Excitatory interneurons to the vagal centero Vagal activation decreases blood pressureo Control system: gene (DNA) - RNA formation - Protein formation - Cell structure/enzyme - Cell functiono STIMULUS-RECEPTOR-CONTROL CENTER-EFFECTOR∙Extracellular fluid = internal environment∙Red blood cell: most abundant cell in body (25/100 trillion)o Produced at rate of 2 million cells per second in a healthy adultelevation vs. depression (shrug), dorsiflexion vs. plantar flexion, pronation vs. supination, inversion (outside sprain) vs. eversion (inside sprain), opposition (tucked thumb) vs. reposition, protrusion vs.retraction (jaw and scapula)∙Caudal, Sagittal, Horizontal are the 3 planeso Mid sagittal is a sagittal plane through the middleo Horizontal is also called transverse∙Cartilage: connective tissue largely composed of proteoglycans with bound water surrounding a collagenous networko Resists tensile force in the matrix and the water-bound proteoglycans resist compressiono Cartilage lacks blood vessels and gets its nutrients from soaking up surrounding fluids by diffusion.Nutrients and wastes move freely into and out of cartilage via fluidso Synovial fluid in a synovial joint can be moved into and out of the cartilage matrix by alternation compression and release of pressure upon the articular cartilageo Hyaline: on articular surfaces in synovial joints and in cartilaginous models for bones, most common type, precursor for bones by ossificationo Elastic: in pinna of the ear and the larynxo Fibrocartilage: in intervertebral discs, symphyses in jaw and pelvis, menisci and intra-articular discs ▪Discs composed of fibrocartilage binding upper and lower faces of vertebral bodies together, encapsulating central gel acting as soft fulcrumo No sensation, damage to cartilage is slow to heal, often irreversible∙Bone:o Compact: rich in blood supply (Haversian systems), alternating layers of collagen fibers running in same direction, resists tensile strain▪Resistance to flexion, extension, torsion▪In gelatinous matrix densely occupied by mineral salts (resist compression) o Trabecular: spongy/cancellous bone forming thin filament sheets with open space between them ▪Comparable strength but much lighter, making bone lighter but not weaker▪May be associated with marrow, forming cellular elements of blood▪Struts in trabeculae adapt in organization to the stress the bone endures▪Osteoporosis: trabecular bone erosion leads to lack of strength for support which leads to collapseo Compact outside, trabecular insideo Blood vessels: Havesian systems built around blood vesselso Forensic/anthropological osteology: understand individual who grew/maintained boneo Osteon: unit of bone formation▪Formation: alternating laminae of collagen fibers laid down in spiral enclosing neurovascular bundle of an artery, a vein, and a nerve∙Collagen fibers embedded in calcium carbonate crystal impregnated gelo Hypoxyapatite: wet, mineral sand∙Bone is strong with all types of straino Bone shaft may be filled with yellow marrow, an adipose connective tissueo Covered internally and externally by periosteum and endosteum: regulate shape/size▪Muscles, tendons, and ligaments are rooted in periosteum and boneo Long: limbs, long lever arms for movement, consist of shaft and articular facets at each endo Short: hand and foot, articulations with several neighbors, collectively support complex movements o Irregular: in skull and vertebral column, surround and protect nervous system and organs of special senses▪In the face there are internal sinuses making the bone lighter (pneumatic) o Flat: cranial vault, ribs, sternum, 2 plates of cortical bone on either side of a central dipoleo Joints: where one bone abuts another bone▪Fibrous∙Sutural: between skull bones, fibrous joints that bind edge to edge, serrate like a jig-saw puzzleo Intervertebral discs: join vertebral bodies, consist of fibrocartilaginous ringcovering superior and inferior cartilaginous plates, filled with nucleuspulposus (gelatinous material) that acts as soft, incompressible but mobilefulcrum▪Cartilaginous: most common type∙Epiphyseal plates and other growth plates, or∙Articular surfaces of synovial joints▪Synovial: involve synovial capsule, fat pad, and fold (ball and socket)▪Many regions contain variety of joints that work together to perform movements▪Movements:∙Planar: no 100% planar joint∙Uniaxial: hinge and pivot∙Biaxial: ellipsoidal/ condyloid and saddle-shaped∙Triaxial: ball and socketo Reticular fiber network supporting haemopoietic cells that pass into sinusoids (specialized vessels with many holes in their walls) and then into general circulationo Many macrophages (cells that eat things) in the center of “focal groups” of developing cellso Apoptotic (dead) cells and organelles have to be removedo Red marrow is gradually replaced by “yellow marrow” fatty tissue in all but a few boneso Bone marrow produces: erythrocytes, leukocytes, neutrophils, eosinophils (less abundant), basophils (less abundant, granules visible), monocytes (less abundant), lymphocytes,megakaryocytes ( produceplatelets)▪ B cells mature in bone marrow, T cell progenitors migrate from bone marrow to the thymus to complete maturationo All above cells are derived from pluripotential stem cells∙Erythropoeisis: approximately 1 week (5-9 days), cytoplasm becomes more acidophilic (red) as hemoglobin formso Unipotent stem cell: starto Proerythroblast: large cell, mitotic, no hemoglobin, all organelles presento Early normoblast (basophilic erythroblast): hemoglobin synthesis begins and cell division stopso Intermediate normoblast (polychromatic erythroblast): decreasing cell size, loss of some organelles, more hemoglobino Late normoblast (orthochromatic erythroblast): nucleus extruded before entering circulation, cell isa bag of hemoglobin exclusively to transport oxygeno Reticulocyte: final maturation, loss of all remaining organelles▪Reticulocytes enter bloodstream through sinusoid▪Immature RBC’s with strands of polyribosomes (chocolate chip cookie)▪1-2% of RBC’so Erythrocyte: synthesis of hemoglobin is complete▪Contain no mitochondria: completely dependent on anaerobic metabolism of glucose to maintain cell▪Anemia occurs when turnover is very rapid▪Biconcave disc ~ 7 microns in diameter, flexible membrane since capillaries are 2-4 microns ∙Slow down and squeeze through capillaries, squeezing releases oxygen ▪Cell shape/flexibility regulated by membrane proteins∙Clots: RBC too rigid or irregularly shaped▪Fragile RBC’s inflexible, tend to rupture, removed by spleen∙Genetic mutations affecting RBC shape:o Hereditary spherocytosis: most common, cells are spherical and less flexible▪Treat by removing spleen to reduce turnover (spleen detects defect)o Hereditary elliptocytosis: ellipses shaped cell, not necessarily bad since cell can still squeeze through capillaries▪Offers a resistance to malaria∙Sickle cell anemia: sickle crisis caused by lack of oxygen or other triggerso Some RBC’s fr om rigid sickle shape leading to clots▪The spleen detects/destroys these cells leading to anemia∙LEUKOCYTES:o Granulocytes/ polymorphonuclear leucocytes: complex nucleus▪Neutrophils (most common): WBC/granulocyte, few organelles other than granules, short lifespan once activated (dead neutrophils = pus)∙Specific granules: collagenase (IV), phospholipase, lysozyme∙Azurophilic granules: lysosomes, defensins∙Tertiary granules: phosphatase, metalloproteinase, reserve membrane proteins▪Eosinophils (1-6%): initiate/modulate the inflammatory response, active in allergy and defense against parasitic worms∙Large, usually dual-lobed nucleus∙Many red/specific granules in matrix (cationic protein, peroxidase, derivedneurotoxin)∙Azurophilic granules: lysosomes▪Basophils (<1%): least common, large blue-ish granules, look like mast cells∙Degranulate after binding to antibody, accumulate in allergy/parasitic disease∙Specific granules: vasoactive heparin sulfate, histamine∙Azurophilic granules: lysosomes∙Modulate T helper lymphocyte responseo Mononuclear leukocytes:▪Lymphocytes (20-50%):∙Sizes:o Small: small nucleus, blue cytoplasm, mitochondria and free ribosomeso Medium: larger nucleus, more cytoplasm, more mitochondiria, prominentGolgi apparatus, RER and free ribosomeso Large: granular lymphocyte, largest∙Functional classifications:o T cells: cell mediated immunity, cytotoxic, helper and suppressoro B cells: humoral immunityo NK cells: natural killer cells, large, granular▪Monocytes (2-10%): largest WBC, nucleus is indented containing few small azurophilic granules (lysosomes), granules usually not visible, cytoplasm is blue-ish∙Monocytes can transform intoo Macrophages when they enter connective tissueso Osteoblasts in bone, eats boneo Alveolar macrophage in lungo Perisinusoidal macrophage in liver, next to sinusoid, vessel with holes to pickthings out and remove things that pass by ito Lymph node and spleen macrophageo Other:▪Platelets: fragment of megakaryocyte cell, small and clumped together, also have granules, lifespan of 10 days∙Clotting:o 1. Stick to and occlude ruptures in blood vessels: complex cytoskeletonallows plate-like shape in circulation and cell projections when activatedo 2. Provide surface for clotting factors to assemble: some membrane proteinssecreted from granuleso 3. Modulate the clotting process▪Megakaryocytes: very large cell in bone marrow, platelet demarcation channels arise through invagination of plasma membrane, fragements break off to form platelets (1000 p/ 1mkc)▪Plasma: 90% water, 8% protein∙Albumin: main protein in plasma that binds and transports thyroxin, bilirubin, drugs, maintains osmotic balance∙Globulins: immune plasma cells and non-immune metal metabolism (Cu, Fe)∙Fibrinogen: largest protein made in liver, participate in clot formationo Mechanical/ structural functiono Exchange medium for nutrients and metabolites between tissues for blood and lympho Defensive functions: lympho Metabolic functions: adipose tissue, bones∙Classifications of connective tissue:o 1. Embryonic connective tissue:▪ a. Mesenchyme: develops into all other connective tissue, often persist in the mature CT but not in great abundance∙Cells are stellate and interconnected, few fibers in a gelatinous matrix▪ b. Mucoid: mucous connective tissue, more specialized∙Few fibers, mostly fetal (Wharton’s jelly in umbilical cord dries out/detaches)∙Postnatally: pulp of developing tooth, vitreous body in eye, nucleus pulposus ofintervertebral disk∙Little developmental potentialo 2. Generalized connective tissue/ CT proper:▪ a. Loose: biologic packing material, areolar (Latin for open space)▪ b. Dense:∙Irregular: many interlaced collagen fiberso Found where the tissues are under mechanical stress▪Encapsulate organs, muscles, nerves▪Reticular layer of dermis of skin▪Outer layer (adventitia) of large blood vessels▪Loose CT can blend into dense CT (transition)∙Regular: bundled fibers oriented in one directiono Tendons: high tensile strength for connecting bone to muscleo Ligaments: highly elastic fibers formed from elastin that connect bone toboneo Fascia: fibers arranged in sheetso 3. Specialized connective tissue:▪ a. Adipose tissue:∙White (unilocular: one blob of fat per cell): dynamic energy storage/endocrineo Small rim of cytoplasm containing organelles and nucleus around lipid∙Brown: abundant in newborn, allows newborn to produce own heato Rich in specialized uncoupled mitochondria that produce heato Multilocular: many lipid droplets per cello Rich in blood vessels resulting in the brown colour▪ b. Bone (MOD3)▪ c. Cartilage (MOD3)∙Components: cells and matrix (ground substance, fibers)o Cells:▪Permanent Cells:∙Fibroblasts: synthesize collagen, reticular and elastic fiberso Complex carbohydrate, active have more basophilic cytoplasmo Abundant RER = more ribosomes: increase when active, Golgi is prominento Closely associated with epithelia: respond to injury/heal wound by rapidproliferation and signaling other cells∙Macrophages: derived from monocytes and rich in endocytotic and phagocytoticorganelleso Contain RER, golgi, mitochondria and an indented nucleuso Surface has projections and folds to engulf foreign matter∙Mast cell: very large cell filled with basophilic granules, involved in allergic responseo Degranulate when stimulated:▪Vasoactive histamine and serotonin▪Slow reacting substance of anaphylaxis and prostaglandins▪Matrix of granules containing peroxidase/superoxidase, heparin,chymotrypsin▪Leads to the attraction of eosinophils and neutrophilso Similarities with basophils: granules stained similarly and rich in histamineand heparin, common progenitor cell, IgE receptors for allergic response,present antigens, immunomodulatory roles are similar, settle in tissues(basophil recruited to lymph nodes)o Differences: circulating basophils have granules while mast cells makegranules after settling in connective tissue, MC granule rich in enzymes(breakdown snake venom), basophils enhance antibody production and havea role in acquired immunity to ticks and insects▪Transient Cells: all blood cells∙Immune cell: plasma B cells produce antibodies, abundant RER and large golgio Heterochromatic nucleus looks like a cartwheel (chocolate chip cookie)o T, B, NK lymphocytes give cell mediated immunityo Matrix (fibers):▪Collagen Fibers: high tensile strength, not elastic, 3 chains of tropocollagen in helix∙Types of collageno I: bone, dentin, cementum, scar tissueo II: hylaline and elastic cartilageo III: reticular fibers (highly glycosylated)o IV: basal lamina (non fibrous procollagen)o V: associates with type I collagen, placentao VIII: basal lamina∙Collagen synthesis:o 1. Fibroblasts: alpha chains made on ribosomes bound to the ERo 2. Hydroxylation of lysine and proline (vitamin C) and glyoosylationo 3. Formation of procollagen triple helixo 4. Packaging in Golgio 5. Secretion (moved from intracellular to extracellular)o 6. Extracellular cleavage: procollagen to tropocollagen, assembly of collagenfibers∙Fibers arranged irregular in loose/dense irregular CT, organized in dense regular CT∙Nuclei present are from scattered fibroblasts, cell relatively small compared to fiber, each cell produces lots of fibers▪Elastic fibers: thin long fibers in bundles or fenestrated sheets of elastin surrounded by microfibrils composed of fibrilin∙Strands randomly aggregated when relaxed, cross-link into fibers when stretched ▪Reticular fibers: very delicate meshwork abundant in lymphoid and myeloid organs that support blood and immune cells∙Type III collagen fibers and carbohydrate, stain with silver to view o Ground Substance:▪Glycosaminoglycans (GAG): hyaluronic acid (primary GAG in loose CT)∙Small, highly expandable∙Hydrophilic and negatively charged (form extracellular fluid by bingding water andsalt▪Proteoglycans: GAGs (chondroitin-, dermatan-, heparin-, heparin-, keratin-sulfate) linked to proteins∙Determines the density(supporting cells)o Nerve cell/neurocyte/neurone/neurons: morphologic and functional unit of nervous system, consisting of nerve cell body, dendrites and the axon▪Unipolar: develop from bipolar neurons = pseudounipolar (dorsal root ganglion)▪Bipolar: transmit impulses for special senses, vision, hearing, olfaction▪Multipolar: most common∙CNS: brain/spinal cord, majority of neuronal cell bodies, collection of cell bodies called nuclei∙PNS: all nervous system outside of CNS, collection of neuronal cell bodies called ganglia∙Axons insulated from surrounding tissue and supported by glial cells:o In CNS:▪Oligodendrocytes from myelin▪Astrocytes provide care and feeding▪Microglia clean up debris▪Ependymal cells: line ventricles and make CSF, no basal lamina, therefore epithelioid▪Schwann cells form myelin∙Non-myelinated nerve fibers are enclosed by Schwann cells∙Myelinated nerve fibers are also enclosed by Schwann cellso Wrap many times around axon like a fruit by the foot∙Each large axon is myelinated by many Schwann cells along length, gaps between Schwann cells = Node of Ranvier, allowing AP to jump node-to-node∙Mesaxons are Schwann cell membranes that encircle the axon like a pillow∙Schmidt-Lanterman clefts/incisures: channels of cytoplasm that remain thatconnect Schwann cell body to innermost myelin layers▪Satellite cells∙Connective tissue of peripheral nerves:o Endoneurium: around each nerve fiber (axon + Schwann cell)o Perineurium: around each bundle (fascicle) of nerveso Epineurium: around (groups of) fascicles▪Composed of loose and dense connective tissue and adipose to cushion/protect nerve o8 nerve fascicles + artery + vein = a triad surrounded by a tough CT sheath (epineurium)∙Ganglion: cluster of nerve cell bodies, ganglion neuron is pseudounipolaro Signals between satellite cells and ganglion neurons may be important in chronic pain and migraineo Muscle cell nuclei and mitochondria cluster near the synapse∙Central Nervous Systemo Grey matter: contains neuronal cell bodies and their processes supported by gliao White matter contains myelinated axons and their supporting glia▪Glial cells: oligodendrocytes, one can contribute to the myelination of up to 50 axons of CNS∙Occur in rows▪Ependymal cells: line the brain ventricles, choroid plexus and spinal cord canal∙Have a free surface, but no basement membrane = epithelioid∙Tactile corpuscles in the skin:o Meissner’s co rpuscles: detect fine pressureo Pacinian corpuscles: deep in the skin, detect coarse pressureo Highly specialized to shorten forcefully (muscle contraction)o Generates large amounts of heat to maintain body temperature∙Classification: by appearance of muscle cells = fiberso Striated muscle fibers exhibit cross-striations▪Skeletal muscle and cardiac muscleo Smooth muscle fibers do not have striations∙Muscle –> muscle fascicle –> muscle fiber (cell) –> myofibril (functional unit = sarcomere) –>myofilaments –> actin and myosin∙Skeletal muscle:o Attach to bone, responsible for movement of skeleton and eyeo Visceral skeletal muscle: tongue, pharynx, upper part of esophaguso No cell-to-cell junctions, cells are bound by connective tissueo Satellite cells: myogenic stem cells located between basal lamina and plasma membrane ▪Contribute to skeletal muscle growth, repair, regenerationo Bound by connective tissue:▪Endomysium: around each muscle cell/fiber▪Perimysium: around each fascicle▪Epimysium: around muscle∙Smooth muscle:o Variable with respect to distribution, size, functiono Found in walls of hollow organs and tubes, in iris and ciliary muscles of the eye, dermis of the skin o Propels urine, mixes food, dilates/contracts pupils, constricts blood vessels▪One per cell in the center▪Elongate, fusiform-shape may look like a corkscrew due to contraction of cell o Cytoplasm: evenly stained without the striated appearance because actin and myosin are not evenly arranged into sarcomere functional units∙Cardiac muscle:o Walls of heart, roots of certain great vessels attached to the hearto Propels blood through circulatory systemo Has sarcomeres and striations, just one or two nuclei per cell in the central regiono Intercalated discs link adjacent cellso Rich in glycogeno 1. Have a free surfaceo 2. Rest on basal lamina (basement membrane)o 3. Polarized with apical, lateral, basal domainso 4. Cells are attached at cell junctionso 5. Avascular▪Epithelium acts as a functional selective barrier between external environment and the connective tissue below it▪Classifications:o 1. Number of layers▪Single: simple/pseudo-stratified, all cells contact the basal lamina∙Simple squamous: in endothelium, mesothelium, alveoli of lungs (super thin)o Facilitates rapid diffusion and active transporto Mesothelium lines body cavities, it is a simple layer of flat cells∙Simple cuboidal: in thyroid follicleo Row of cubes, nuclei reflect shape of cell (also for columnar)o Sometimes height depends on hormones (taller is faster/more active, shorteris slower)▪Also for columnar∙Simple columnar: in intestineo Nuclei towards the base and cytoplasm towards the top∙Pseudo-stratified columnar: in the tracheao Nuclei are random (at different levels) in the epithelial cello All cells touch the basal lamina, only the tallest ciliated cells reach the freesurfaceo Some of the shorter cells act as stem cells▪Multiple: stratified, only the basal cells (bottom-most) contact the basal lamina∙Named by the type of cell forming uppermost layer∙Stratified squamous: formation (in basal layer), maturation, and loss of cells Iscontinuouso Keratinized/cornified: drying or abrasive conditions (air exposure)▪Upper cells die forming a layer of dead cells (fingertip)o Non-keratinized: no drying from abrasion (moist surfaces/cavities)∙Stratified cuboidal/columnar: ~2+ layers of cuboidal/columnar cellso Often found in ducts/exocrine glandso No continuous division in basal layer, no layer of reserve cells at the bottom o 2. Shape of the cells in the layer next to free surface▪Flat/squamous, square/cuboidal, tall/columnaro 3. Specializations▪Structural or functional specializations▪Urothelium: transitional epithelium (REMEMBER ODD APPEARANCE, UNIQUESTRUCTURE/FUNCTION) – in the bladdero Lines urinary tract 9uro) from kidney to proximal part of urethra▪Mesoderm, ectoderm, and endoderm originso Prevents exposure to toxic contentso Surface covered by specialized plasma membrane with plaques of intramembranous glycoprotein ▪Plaques partially internalized when tissue is relaxedo Can be stretched/flattened while maintaining cell to cell contact▪Large surface cells may be polyploidy▪Polarity: depends on and arises from the asymmetric distribution of cytoplasmic and membrane proteins o Top apical, middle lateral, bottom basalo PM proteins are targeted to respective domains, some are key in establishing epithelial cell polarit▪Cell junctions: facilitate selective permeability and strengtho Cell-to-cell:▪Zonulaoccludens: tight junction (apical), intracellular attachment is ACTIN∙Found in intestine, endothelium, blood-brain barrier∙Integral membrane proteins can be separated into domains by tight junctions –polarity▪Zonulaadherens (apical-lateral) intracellular attachment is ACTIN∙Adhering junction indirectly attaches to actin filaments of cytoskeleton of adjacentcells∙*Zonula: all the way around the cell like a band▪Desmosomes: macula adherens (lateral-basal) –SPOT WELDS, intracellular attachment is INTERMEDIATE FILAMENTS∙Adhering junction that attaches intermediate filaments of one cell to theintermediate filaments of an adjacent cello Cell-to-matrix:▪Hemidesmosomes: focal adhesion (basal), intracellular attachment is INTERMEDIATE FILAMENTS▪Adhering junction that attached IF of one cell to the basal lamina of that same cell o Communication junction: gap junction (lateral)▪Provides conduit for passage of small molecules from one cell to another∙Important in tissues where activity is coordinated between cells▪Surface specialization of apical domaino Microvilli: abundant in gut and bladder▪Small finger-like projections on the apical surface of epithelial cells, few to many∙Most in cells in absorptive epithelium: intestine where nutrients absorbed ▪Anchored to cells of the cytoskeleton▪Striated border is precise while brush border is looseo Stereocilia (long microvilli): epididymis/ductus deferens in male reproductive and sensory hair cells of ear only▪NOT CILIA, not motileo Cilia: abundant in trachea and fallopian tubes▪Motile and beat with a synchronous, coordinated rhythm▪Microtubule core▪Surface specialization of lateral and basal domainso Infoldings:▪Lateral for strength, transport, microc-ompartments∙Stratum spinosum in skin▪Basal for specialized transport∙Kidney, base of striated ducts in salivary glandso Basement membrane/basal lamina▪Narrow layer of ECM between epidermis and connective tissue▪Composed from contributions of epithelium (more) and connective tissue (less)▪Functions to:∙Support epithelial cells∙Anchor epithelial cells to connective tissue∙Barrier for control of epithelial growth∙Permeability barrier: anionic filters in kidneys▪Major constituents are: proteoglycans, collagen IV, laminin, entactin▪External lamina: muscle, nervous tissue, adipose tissue▪Mucosa: mucous membrane∙Epithelium and underlying loose connective tissue (lamina propria)∙Surfaces connected with the outside of the body, may have glands▪Serosa: serous membrane∙Mesothelium and underlying loose connective tissue∙Closed cavities, no glands▪Glands are made of epithelial cells:o Exocrine glands: connected to the surface (often ducts)▪Classified by:∙Number of cells: unicellular, multicellular∙Means of secretions:o Merocrine: no loss of membrane (fusion of vesicle)▪Secreted by fusion of a vesicle with the membrane, no loss ofcytoplasmo Holocrine: whole cell breaks down▪Secretion by breakdown of the cell, complete loss of cytoplasm andthe cello Apocrine: mammary gland (lipid)▪Secretion of a lipid droplet by budding, droplet surrounded by cellularmembrane and a small amount of cytoplasm (some loss of cytoplasm) ∙Type of secretion;o Mucous: just mucouso Serous: varieso Gland morphology:▪ 1. If secretory and duct portions are different (if there is a duct)▪ 2. If duct is branched (compound) or not branched (simple)▪ 3. Shape of secretory portion:∙Tube = tubular, long∙Flask/round = acinar/alveolar∙Tubo-acinar is hybrid▪ 4. If secretory portion is coiled or branched▪EX.∙Simple tubular glands: cardiac stomach lining∙Simple coiled tubular glands: sweat glands in skin∙Simple branched tubular glands: lining of the fundic stomach∙Simple branched acinar gland: sebaceous glands in skino Sebaceous: exhibits holocrine secretion (waxes and oils)▪Cell accumulates oil and breaks down, debris released into duct∙Compound branched tubular gland: glands in intestine∙Compound acinar gland: salivary glands, pancreas∙Compound tubulo-acinar gland: salivary gland, mammary glando Mammary: apocrine and merocrine secretion/transcytosis▪Lipid released surrounded by rim of cytoplasm and membrane(apocrine)▪Protein released by exocytosis (merocrine)▪IgA transported across epithelium unchanged (transcytosis) o Endocrine glands: secretory (epithelial) cells that have lost connection to the surface Secrete into the connective tissue, taken up by blood vesselsthe largest organo Protection: acts as a mechanical, chemical, water, UV, microorganism barriero Sensory function (feeling)o Body temperature regulation through: insulation, perspiration, blood circulation controlo Synthesis of vitamin D (sunlight exposure)o Excretion。