Histology PDF

Four Major Types of Tissues 1st group The Epithelial Tissues Epithelial Tissues General features:  Diversity: shapes, layers, and functions ▪ Secretion ▪ absorption...

Four Major Types of Tissues 1st group The Epithelial Tissues Epithelial Tissues General features:  Diversity: shapes, layers, and functions ▪ Secretion ▪ absorption ▪ protection  Lining and Covering ▪ Body surfaces and body cavities ▪ Mesothelium (body cavities) ▪ Endothelium (blood vessels) ▪ Endothelial cells ⚫ Basal lamina & Apical surface ⚫ extracellular basement membrane ⚫ Unattached surface Renewal Closest to BL undergo mitosis continuously Avascularity BL rarely penetrated by blood vessels ET CT Cell packing With very little intercellular substance Densely packed, joined by specialized junctions  Derivation Ectoderm, mesoderm, endoderm Ectoderm ▪ Keratinized layer of the skin ▪ Sweat glands and ducts ▪ non-keratinized strat. squa. epithelium Lining of oral cavity, vaginal and anal canal Mesoderm ▪ Endothelium ▪ Mesothelium ▪ Linings of urinary ducts and tubules Endoderm ▪ Lining of the esophagus (non-keratinized sq.epith) ▪ Lining of the GIT (simple columnar) ▪ Solid glands (liver, pancreas) ▪ Lining of the RT (pseudostrat. ciliated columnar →simple ciliated columnar)  Classification ⚫ According to morphological characteristics ⚫ Number of cell layers ⚫ Shape of surface cells ⚫ Presence of surface specializations ⚫ Specialized secretory function ⚫ Glandular epithelium Specific Epithelial Types ⚫ Simple epithelia ⚫ Simple squamous ▪ Single layer, flattened cells ▪ In blood vessels (endothelium) ▪ In body cavities (mesothelium) ▪ Forms parietal layer of renal corpuscles Specific Epithelial Types ⚫ Simple cuboidal ⚫ Blocklike cells, line walls of secretory and excretory ducts ⚫ Protective barrier ▪ In kidney tubules ▪ Glandular ducts ▪ Ovary covering ▪ Lens capsule’s inner surface Specific Epithelial Types ⚫ Simple columnar ⚫ Roughly cylindrical-shaped cells ⚫ Secretion, absorption, propulsion of mucus ⚫ Protective barrier ▪ In lining of stomach, intestines, rectum, ▪ uterus, oviducts ⚫ Pseudostratified ciliated epithelium ⚫ with cells of variable shapes and height, nuclei at two or more levels ⚫ Cells at the surface often ciliated (ciliated PE) ▪ In respiratory epith. ▪ Larger respiratory passages ▪ Parts of male reproductive tract ( with sterocilia) ⚫ Stratified epithelium ⚫ Two forms: ▪ Keratinized: ▪ with dead, enucleated surface cells ▪ In skin ▪ Non-keratinized: ▪ with flat, nucleated cells ▪ Lining of the mouth, esophagus ▪ Lining of vagina, anal canal ▪ Vocal cords (keratinized) ⚫ Stratified cuboidal epithelium ⚫ With two or more layers ⚫ Relatively rare Large excretory ducts of exocrine glands (salivary and sweat) ⚫ Stratified columnar epithelium ⚫ Resembles stratified cuboidal but columnar superficial cells ⚫ Columnar cells maybe ciliated ⚫ Relatively rare ▪ Forms the conjunctiva ▪ Respiratory surface of epiglottis ▪ Small patches in some mucous membrane ⚫ Transitional epithelium ⚫ Specialized to accommodate great degree of stretch ⚫ Surface cells large, often binucleated ⚫ Intermediate cells roughly polygonal ⚫ Basal cells roughly cuboidal ▪ Lining of renal pelvis ▪ Ureter ▪ Urinary bladder proximal urethra Membrane specializations of epithelia ⚫ At the intercellular surfaces: ⚫ Occluding junctions/tight junctions/zonula occludens ⚫ Adhering junctions/belt desmosomes/ zonula adherens ⚫ Communicating junctions/gap junctions At the Apical surface ⚫ Cilia ⚫ Microvilli ⚫ Stereocilia ⚫ At the basal surface Basal lamina/ basement membrane Hemidesmosomes ⚫ Occluding junctions ▪ Seal intercellular spaces ▪ forms continuous band/zonule around the cell ▪ Beneath luminal surfaces of simple columnar epithelium ⚫ Adhering junctions ⚫ Tightly bind cells together ⚫ Anchorage sites of cytoskeloton ⚫ Form circular patches, desmosomes ⚫ Communicating junctions ⚫ Circular intercellular contacts ⚫ With numerous pores (allow passage of small molecules) ⚫ Cilia ▪ Membrane-covered, cell-surface extensions ▪ Typically cover entire apical surface ▪ Relatively long, motile structures ⚫ Microvilli (striated border or brush border) ▪ Extremely numerous projections of the plasma mem. ▪ Relatively short, contractile structures ⚫ Stereocilia ▪ Long microvilli ▪ Usually found singly or in small numbers ▪ Non-motile Basal lamina/ basement membrane ▪ Non-cellular, sheet-like structure ▪ With 2 layers: lamina lucida and lamina densa ▪ Functions: = sievelike barrier between ET and CT = maintains cell shape = tissue organization ⚫ Hemidesmosomes ▪ In the inner surface of plasma membrane ▪ Provide anchorage for cells to the basement mem and underlying connective tissue The glandular epithelia ⚫ Invaginations of the epithelial tissues ⚫ Involved in secretion ⚫ Exocrine ▪ Secretions via duct The exocrine ducts ⚫ Classification as to structure: ⚫ Unicellular ⚫ Multicellular ▪ Simple (straight/coiled) ▪ Compound ) duct ▪ Tubular ▪ ▪ Acinar tubuloacinar ) Secretory portion ⚫ Classification as to type of secretory products: ⚫ Mucous ⚫ Serous ⚫ Seromucous ⚫ Classification as to mode of secretion ⚫ Merocrine ⚫ Apocrine ⚫ Holocrine  Examples of structural classification of multicellular exocrine glands: Duct system Secretory portion Example Simple tubular Intestinal crypts of Lieberkuhn Simple Coiled tubular Eccrine glands of the skin Simple Branched tubular Fundic glands of the stomach Simple Branched acinar Sebaceous glands of the skin Compound tubular Cardiac glands of the stomach Compound Tubuloacinar Submandibular salivary glands Compound acinar Exocrine glands of the pancreas Guide questions for independent learning: ⚫ Describe the specialized of the various epithelial cell types and give examples of body sites where they are found ⚫ The epithelial cells specialized for secretion: ⚫ Protein-secreting cells ⚫ Polypeptide secreting cells ⚫ Mucous cells ⚫ Serous cells ⚫ Steroid secreting cells ⚫ Myoepithelial cells ⚫ Know the functional capabilities of epithelial tissue types and relate them to tissue structure ⚫ Know the criteria to classify glands (glandular epithelia)  Four Major Types of Tissues 2nd group The Connective Tissues For classroom use only - GBRamos  Connective Tissues General Features 1. Embryonic origin: mesenchyme For classroom use only - GBRamos  2. Wide range of functions: Structural support ▪to compartmentalize, to bind, to fill spaces) Example:  Defense ▪Physical and immunologic protection Physical defense due to: ▪ Viscosity of the extracellular matrix (hyaluronic acid) ▪ Tightly packed sheets of interwoven CT fibers (confine local infections) Immunologic protection due to: immunoresponsive cells that inhabit underlying CT Wandering/immigrant cells from blood or bone marrow - mast cells - macrophages - plasma cells - leukocytes/WBCs  Storage Fats/lipids Water, electrolytes, sodium  Repair Close breaches in the body’s protective barriers Invasion if the site of injury by immunocompetent cells (macrophages) Proliferation of fibroblasts (secrete ECM) Transport Mediate exchange of nutrients, metabolites and waste products Function of the blood and loose CTs 3. CT with three (3) fundamental components: ▪ Ground substance/Extracellular matrix/ intercellular matrix/ECM/ICM ▪ Fibers ▪ Cells ❖ CT with large amount of intercellular matrix ❖ CT cells are loosely arranged ❖ CTs are vascular ( contain blood vessels)  Areolar CT (200x) Source: Histo Lab SJ 602 For classroom use only - GBRamos  Fundamental components 1. The Ground Substance Proteoglycans Composed of core protein w/ attached glycosamino-glycans Ground substance (GAGs) Glycoproteins Proteins with attached branched polysaccharides For classroom use only - GBRamos  Hyaluronan/hyaluronic acid Heparan sulphate GAGs Dermatan sulphate Keratan sulphate I & II Chondroitin-4- sulphate Chondroitin-6-sulphate  GAGs Locations Synovial fluid Hyaluronic acid Wharton’s jelly of umbilical cord (hyaluronan) Vitreous humor of the eye Basal laminae Heparan sulfate Interalveolar septa in lungs Liver Aorta Skin Dermatan sulfate Tendons Heart valves Cartilages and bones Chondroitin sulfate Blood vessels  Fibronectin Mediates cell adhesion to the ECM Laminin mediates cell adhesion to the epith. tissues Glycoproteins chondronectin Tenascin, integrins Cell adhesion molecules, (CAMs) mediate linkages between ECM & cytoskeleton)  Glycoprotein Location Connective tissues Fibronectin Basal laminae surfaces of fibroblasts * Linking cells, collagen, GAGs Laminin Basal laminae Same as fibronectin Chondronectin *adhesion factor for chondrocytes  Fundamental components (Collagen. Elastic, reticular) 2. The CT Fibers Collagen fibers Occurring in small and large bundles of fibrils (Tough and bulky) Most abundant, (all types of CTs) with great tensile strength  Collagenous bundles with different stains H & E stain Trichome stain Azan blue stain For classroom use only - GBRamos Collagen types: ▪ Type I: most abundant and widespread in tendons, ligaments, bone, dermis, organ capsules, loose connective tissue ▪ Type II: in adults only, cartilage matrix ▪ Type III: flexible tissues, smooth muscles, major component of hematopoietic tissues, reticular networks in the skin and GIT ▪ Type IV: major type in basal lamina ▪ Type V: in placental basement membrane and blood vessels ▪ Type X: in matrix surrounding hypertrophic chondrocytes and degenerating cartilages in bone forming plates  Adrenal capsule Adrenal gland (LPO) Source: Histo Lab SJ 602 For classroom use only - GBRamos  Integument (LPO) Loose collagenous tissues Source: Histo Lab SJ 602 For classroom use only - GBRamos  Elastic fibers Occur as short branching, irregular networks, thin cylindrical, flat threads Consist of amorphous protein elastin and protein microfibrils Pliable and elastic Locations: – Arterial walls, – interalveolar septa – bronchi and bronchioles – vocal ligaments – ligamenta flava of vertebral column  ▪ elastic fibers require special stains to be visualized. ▪ Light microscopy does not reveal any substructure in the elastic fibers Weigert’s resorcin-fuchsin; Verhoeff’s stain Special stains to visualize elastic fibers For classroom use only - GBRamos Arterial wall (HPO) Source: Histo Lab SJ 602  Reticular fibers ▪ Form networks instead of bundles ▪ Form supportive lattices for motile cells in hematopoietic tissues ▪ Supporting framework for organs like: liver, lymph nodes, and endocrine glands (support for individual cells of these organs) For classroom use only - GBRamos  Fundamental components 3. The CT cells ▪ 2 types: 1. Fixed cells native to the tissues where they are found ▪ mesenchyme cells, fibroblast cells ▪ reticular cells, adipose cells/adipocytes 2. Wandering cells Immigrant cells, from blood or bone marrow ▪ mast cells, macrophages, plasma cells ▪ Other blood-derived connective tissue cells  Mesenchymal cells ▪ Precursor of most connective tissues ▪ Embryonic mesenchyme: – Loose network of stellate cells – with abundant intercellular matrix ▪ Adult mesenchyme – Some remain undifferentiated; resemble fibroblast – Reserve population of adventitial cells in b.v. walls For classroom use only - GBRamos  Adipose cells/adipocytes specialized for lipid storage Filled with lipid droplets, hence the nucleus is Adipose Ct (LPO) displaced to the cell Source: Histo Lab SJ 602 periphery Adipose Ct (HPO) For classroom use only - GBRamos Source: Histo Lab SJ 602  Mast cells Derived from bone marrow precursors With abundant basophilic cytoplasmic granules Incospicuous nucleus ❖ involved in allergic reactions Cytoplasmic granules: » Histamine » Heparin » Eosinophilic chemotactic factors For classroom use only - GBRamos  ▪ Fibroblasts/fibrocytes Most predominant cells in the connective tissue Synthesize, secrete, maintain all major components of extracellular matrix Large and flat, spindle-shaped Fibrous Ct (LPO) Source: Histo lan SJ 602 For classroom use only - GBRamos  Two types: Mitotically active – Stellate cells with long cytoplasmic processes, large, ovoid, pale-staining nucleus, abundant RER and Golgi complex Less active (fibrocytes); mature – Smaller spindle-shaped, with dark, elongated nucleus, – fewer organelles For classroom use only - GBRamos  Reticular cells Typically stellate with long cytoplasmic processes with central, pale, irregularly rounded nucleus with distinct nucleolus Produce reticular fibers Phagocytose antigenic materials and cellular debris For classroom use only - GBRamos ▪ Macrophages Large, stellate cells derived from blood monocyte lineage, contain many lysosomes, granules, vacuoles For phagocytosis ❖multinuclear giant cells: fused macrophages ❖mononuclear phagocyte system (MPS) » Kupffer cells (liver) » microglial cells (CNS) » osteoclasts (bone) For classroom use only - GBRamos ▪ Plasma cells Differentiated cells from antigen-stimulated B lymphocytes; contain more cytoplasm than lymphocytes Large, ovoid cells with eccentric nucleus, abundant RER Primary producers of circulating antibodies Abundant in areas susceptible to penetration by bacteria For classroom use only - GBRamos  ▪ Other blood-derived CT cells Include leukocytes which have roles in immune response Monocytes, lymphocytes, basophils, neutrophils, eosinophils For classroom use only - GBRamos The Grouping/Classification of Connective Tissue Types  1. Embryonic Connective Tissue Mesenchyme CT (alternative names) Mucous CT (Wharton’s jelly) Unspecialized CT in embryonic life Transient type in normal dev’t Undergo differentiation W/ mucin in the ground substance Makes up the umbilical cord Characteristic feature: ❖ Few cells & fibers distributed randomly in abundant ground substance For classroom use only - GBRamos  2. Connective Tissue Proper Characteristic feature: ❖ Predominance of fibers (mainly type I collagen) in the ECM Char. feature: Char. feature: -Disorganized Loose -different types of fibers Dense - predominant collagen fibers - predominant fibroblast cells -many kinds of fixed & wandering cells Areolar CT Mesenchyme/ Mucous Regular Irregular Tendons & ligaments, Reticular layer Periosteum & Perichondrium of dermis Capsules of joints & organs  Areolar CT For classroom use only - GBRamos  Dense regular CT perichondrium For classroom use only - GBRamos  Dense regular CT: Organ capsule Lymph node Source: Histo Lab SJ 602 For classroom use only - GBRamos Dense irregular CT: Dermis of the skin  3. Specialized CT Adipose Tissue Elastic Tissue Reticular Blood Tissue Hematopoietic organ-tissues: Ligamenta flava (vertebral column) bone marrow vocal ligament, spleen Suspensory ligament of penis Lymph nodes  Reticular tissues: hematopoietic organ- tissues Bone marrow (LPO) Source: Histo lab SJ 602 For classroom use only - GBRamos  Reticular tissues: hematopoietic organ-tissues Spleen (LPO) Source: Histo Lab SJ 602 N_HL_SP_23 Lymph node (LPO) For classroom use only - GBRamos Source: Histo Lab SJ 602  Elastic tissue For classroom use only - GBRamos  Adipose Tissues Adipocytes/fat cells as fuel storage Clusters of adipocytes scattered throughout the body Clusters of adipocytes divided into lobules by septa of connective tissues For classroom use only - GBRamos  Adipose tissues White/unilocular Brown/multilocular Adipose tissues Adipose tissues Containing single fat droplet multiple small lipid droplets With signet ring appearance rich in mitochondria Larger than brown adipocytes smaller than white adipocytes For classroom use only - GBRamos  White adipose Brown adipose (more widely distributed) (less abundant in all ages) Subcutaneous fats In fetuses: ❖ panniculus adiposus in the axilla, Back of the neck, around renal hilus Intra-abdominal fat Other locations: eye orbits, surrounding knees pads of palms and soles ❖ brown fat due to rich ❖ Yellow fat due to dietary mitochondrial content; carotenoids Mitochondrial cytochromes  4. Supporting CT Cartilages Bones Cancellous bone Hyaline cartilage Elastic cartilage Compact bone fibrocartilage  Characteristics of cartilage types Cartilage Cell type Fiber type Hyaline Chondrocytes Type I collagen Elastic chondrocytes Elastic fibers and type II collagen Fibrous chondrocytes Type I and II collagen ❖ Chondrocytes are housed in cavities called lacuna(e) Cartilage Ground substance Organization Hyaline Predominant abundant ground substance components Lack of capillaries are GAGs, Chondrocytes occur singly or in mainly chondroitin isogenous groups sulfate Fibers difficult to distinguish Enclosed with perichondrium Elastic Same as hyaline Identical to hyaline with dense network of elastic fibers enclosed with perichondrium Fibrous Similar to hyaline but Cross between cartilage and dense with equal amounts of reg. CT chondroitin and Chondrocytes occur in rowlike dermatan sulfates isogenous groups Perichondrium absent  Cartilage Locations Fetal skeleton Hyaline Articular cartilages Costal cartilages Laryngeal, tracheal, bronchial cartilages External ear Elastic Auditory tubes Epiglottis Conniculate and cuneiform cartilages in the larynx Annulus fibrosus (invertebral disks) Fibrous Pubic symphysis Bone-ligament junction ❖ Fibrocartilage is always found in association with dense CT  Hyaline cartilage Perichondrium For classroom use only - GBRamos  Elastic cartilage For classroom use only - GBRamos  fibrocartilage For classroom use only - GBRamos For classroom use only - GBRamos  The Bones With abundant mineral salts Hard Connective tissue For tissue prep: Requires: grinding & demineralizing For classroom use only - GBRamos  Spongy bone (cancellous bone) architecture Compact bone (lamellar bone) Primary bone (woven bone) Fine structure Secondary bone  Long bones Shape Short bones Flat bones  Endochondral bone Formation process Membrane bone  PARTS of Long Bones Compact bone For classroom use only - GBRamos For classroom use only - GBRamos  Spongy bone/cancellous bone Network of irregular plates (trabeculae) Labyrythn of spaces (marrows) For classroom use only - GBRamos Compact bone For classroom use only - GBRamos  Bone surfaces/capsule: ⚫ Periosteum  Outer layer, Fibrous layer,  Osteogenic layer= inner layer ❖ Sharpey’s fibers periostal collagen fibers that penetrate bone matrix; anchor periosteum to bone  Endosteum ⚫ Inner layer, condensed CT ⚫ Contain bone and blood cell precursors ⚫ Lines marrow cavities; extends into Haversian canals  Bone tissue composition BONE Bone cells Bone matrix Osteoprogenitor Osteoblasts Osteoid/organic components Osteocytes Inorganic components Osteoclasts Osteoprogenitor cells Osteoblasts Stem cells found in the Major bone-forming cells endosteum and periosteum precursors of osteoblasts and Osteocytes osteoclasts Terminally differentiated bone cells Osteoclasts Bone-resorbing cells For classroom use only - GBRamos  https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcTik533OSkW3PSxK7cOBXNA6r9zdXLkhY6gzMNRW3KQ4rJFtqUx https://encrypted-tbn3.gstatic.com/images?q=tbn:ANd9GcSj6ZlPqIF65Yiti3iVrI0Qktm2GqDtC6Fpy1wwGdu6z7XTaLiI For classroom use only - GBRamos  https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcSlNfQq_tZAVCC55tdqveyTVTMB-kzo_cpzgga85Wg5JgwQOjuB  Osteoclasts ⚫ Bone-resorbing cells ⚫ Lying on bony surfaces in shallow depressions, (Howship’s lacunae) ⚫ large, multi-nucleated, with acidophilic cytoplasm ⚫ Ruffled cytoplasm https://encrypted-tbn3.gstatic.com/images?q=tbn:ANd9GcS78oIMZYq-affMaklcIhpr1-jD3YbosrWDx1qsll3-nBlTqmM93Q For classroom use only - GBRamos  Osteoprogenitor cells ⚫ Stem cells found in the endosteum and periosteum ⚫ precursors of osteoblasts and osteoclasts ⚫ Spindle-shaped cells with ovoid to elongate nuclei ⚫ unremarkable cytoplasm  Osteoblasts ⚫ Major bone-forming cells ⚫ Cuboidal shape, round nucleus; basophilic cytoplasm ⚫ Found on the surfaces of new bone formation ⚫ Synthesize & secrete all organic components of bone matrix ⚫ Proteoglycan aggregates ⚫ Alkaline phosphatase ⚫ Calcium-binding proteins (osteocalcin, osteonectin) ⚫ Adhesive glycoproteins (sialoproteins, osteopontins)   Osteocytes ⚫ Terminally differentiated bone cells ⚫ Found in cavities of bone matrix, (lacunae) ⚫ Retain synthetic and resorptive capacity  Osteoclasts ⚫ Bone-resorbing cells ⚫ Lying on bony surfaces in shallow depressions, (Howship’s lacunae) ⚫ large, multi-nucleated, with acidophilic cytoplasm ⚫ Ruffled cytoplasm Organic components/Osteoid ⚫ Constitute approximately 50% of bone volume; ⚫ 25% bone weight Fibers: 90-95% type I collagen Ground substance: multicomponents: proteins, carbohydrates, lipids proteoglycans GAGs (chondroitin and keratan sulfates)  Inorganic components ⚫ Bone minerals make up 50 % bone volume; 75% bone weight ⚫ Consists mainly of Calcium and Phosphate hydroxyapatites → needle-like crystals of calcium and phosphate ⚫ With some bicarbonates, citrate, magnesium, potassium, trace metals  Histogenesis, Remodelling, Growth and Repair  Intramembranous ossification ⚫ Direct replacement of mesenchymal tissue by bone ⚫ New bone formation For classroom use only - GBRamos  Endochondral ossification ⚫ Involves replacement of cartilage by bone (progressively) ⚫ Occurs in all except membrane bones ⚫ Examples:  Long bones  Vertebrae  Pelvis  Base of the skull Bone development is controlled by growth hormones, thyroid and sex hormones Basic steps in endochondral ossification  Cartilage model  Periosteal bone collar formation  Proliferation  Hypertrophy  Calcification  Formation of primary bone marrow  Periosteal bud formation  Ossification  Formation of primary bone marrow cavity Periosteal bud Calcification formation Endochondrial ossification Hypertrophy Proliferation Periosteal bone collar formation Ossification Cartilage model For classroom use only - GBRamos For classroom use only - GBRamos  Overlapping zones in developing endochondral bone  Zone of resting cartilage  Zone of proliferation  Zone of hypertrophy  Zone of calcification For classroom use only - GBRamos For classroom use only - GBRamos For classroom use only - GBRamos For classroom use only - GBRamos For classroom use only - GBRamos For classroom use only - GBRamos  The Joints: (arthroses) Synarthroses Diarthroses (little/no movement) (movable joints) synostoses synchondroses syndesmoses  Synostoses ⚫ Fused and immobilized  Bones of the skull  Synchondroses ⚫ Bones joines by cartilages  Between ribs and sternum, in the pubic symphysis  Syndesmoses ⚫ Bones joined by dense CT  Bones of the skull (young); tibiofibular articulation Four Major Types of Tissues 3rd group The Muscle Tissues  GENERAL FEATURES Special terms for MT : include the prefixes sarco- or myo Examples: sarcolemma, sarcoplasmic reticulum, sarcoplasm, myofiber, myofibril 1. Specialized for contraction structurally & functionally 2. Cell shape: longer than they are wide (muscle cell = muscle fiber = myofiber) 3. Organized as group of muscle cells unsheathed with connective tissue 4. Nearly all muscles arise from mesoderm (except smooth muscle of the iris w/c is from ectoderm) STUDY GUIDE 1. Know the three types of muscle tissues 2. Compare & contrast - Structure, function, location - Distinguishing characteristics 3. Know the relationships between: ▪ muscle fascicles, muscle fibers, ▪ myofibrils, and myofilaments ▪ their corresponding connective tissue sheaths 4. Know the roles of T tubules, sarcoplasmic reticulum, the dyads, the triads STUDY GUIDE Fill up the table below Distinguishing characteristics of muscle types Features Skeletal Muscle Cardiac Smooth Muscle Muscle Appearance striated striated Non-striated Cells (shape) Nuclei per cell Filament ratio Sarcoplasmic reticulum & myofibrils T tubules Motor end plates Motor control Other Four Major Types of Tissues 4th group The Nervous Tissues  GENERAL FEATURES  Specialized for impulse conduction  Two classes of cells: 1. Neurons (nerve cells)  W/ soma/perikaryon (nerve cell body)  W/ single axon (myelinated & unmyelinated)  W/ variable number of dendrites Study guide: 1. Describe/know how neurons receive, propagate, and transmit nerve impulses. Know the role of the parts (soma, axon, dendrites) of a nerve cell 2. Describe/know the organelles of neurons in terms of their intracellular location, and their roles in transmitting nerve impulses  GENERAL FEATURES 2. Supporting cells (neuroglia/glial cells) 3. All neurons and glial cells are derived from ectoderm neural crest cells give rise to: - sensory neurons of craniospinal ganglia, - Schwann cells - satellite cells of ganglia Study guide: 1. Know the different supporting glial cells found in the Central NS 2. Know the different supporting glial cells found in the Peripheral NS 3. Know their positions/locations 4. Know their characteristic features, roles/functions 5. What are ganglia?What are the 2 major types? Study guide: 6. What are peripheral nerves? 7. Know the characteristic features of peripheral nerves. (Compare/contrast unmyelinated vs myelinated nerve) 8. Know: relationships between a nerve, nerve fascicles, nerve fibers, and their corresponding connective tissue sheaths  Essential Terms integumentary system skin and all of its accessory structures – Hair and nails – Nerves and blood vessels – various glands – muscles cutaneous membrane – another name for skin  Introduction Skin 1. covers the external surface of body 2. largest organ of the body in surface area and weight 3. Functions: temperature regulation water repellent barrier to external environment provide sensory information excrete wastes synthesizes vitamin D protect underlying tissues from UV radiation Skin Composition  Layers of Integument Epidermis – most superficial Dermis – deep to epidermis Hypodermis – anchors the dermis Figure 1.1a Figure 1.1b  Skin Structure Two principal parts of the skin 1. epidermis thin composed of epithelial tissue 2. dermis thicker composed of connective tissue Hypodermis – deep to dermis but not part of skin – subcutaneous layer – areolar and adipose tissues – fibers from dermis anchor it to hypodermis Table 5.1  Epidermis composed of keratinized stratified squamous epithelium four principal types of cells 1. keratinocytes 2. melanocytes 3. Langerhans cells 4. Merkel cells Figure 5.2a Figure 5.2b  Layers of Epidermis Deepest to most superficial stratum basale stratum spinosum statum granulosum stratum lucidum (only in thick skin) stratum corneum  Stratum Basale single row of cuboidal or columnar keratinocytes – some are stem cells continually undergo cell division melanocytes and Merkel cells found scattered here also  Stratum Spinosum 8 to 10 layers tightly packed many-sided keratinocytes most superficial become somewhat flattened microscopic preparation shrinks cells – they pull apart and appear covered with spines – living cells are rounded and plump, however  Stratum Granulosum middle most layer 5 layers of tightly packed many sided keratinocytes flattened undergoing apoptosis granules are membrane-enclosed lamellar granules – release lipid-rich secretion water-repellent  Stratum Lucidum present only in thick skin 3 to 5 layers of clear flat dead keratinocytes – cells contain large amounts of keratin  Stratum Corneum most superficial layer 25 to 30 layers of dead flat keratinocytes continually shed and replaced by cells from deeper strata interior of cells mostly keratin lipids from lamellar granules is between cells protects against injury and microbes serves as effective water-repellent  Melanocytes found in deepest layer of epidermis produce melanin – pigment that blocks UV radiation – clusters around nucleus of cells long slender projections extend between keratinocytes and transfer melanin to them melanocytes provide protective melanin to keratinocytes but vulnerable to UV radiation themselves  Keratinocytes most numerous arranged in 4 or 5 layers produce keratin produce lamellar granules – waterproofing sealant  Langerhans cells small fraction of epidermal cells participate in immunity easily damaged by UV radiation  Merkel Cells least numerous of epidermal cells located in deepest layer contact flattened process of sensory neuron a tactile (Merkel) disc function together with the disc in sensation of touch Table 5.1  Keratinization and Growth cells of stratum basale pushed toward surface as new cells appear more keratin produced along the way takes about 4 weeks in average epidermis Table 5.2 Dermis  Dermis deep to epidermis composed mainly of connective tissue – containing collagen and elastic fibers embedded in dermis – blood vessels, nerves, glands, hair follicles cells of dermis – fibroblasts – macrophages – adipocytes  Layers of Dermis papillary region – 1/5th of total dermis – areolar connective tissue with fine elastic fibers – surface area enhanced by dermal papillae – contain capillary loops corpuscles of touch (Meissner corpuscles) free nerve endings  Layers of Dermis reticular region – 80% of dermis – attached to hypodermis – consists of denser irregular connective tissue collagen fibers and some coarse elastic fibers – between fibers are » hair follicles » nerves » sebacous glands » sudoiferous glands – provides extensibility and elasticity – extreme stretching of dermis causes striae (stretch marks) Figure 5.1a Figure 5.1b  Layers of Dermis epidermal ridges – either straight lines or loops – caused by epidermis projecting into dermis between dermal papillae – increase surface area – function to increase grip of hands and feet – glands open on tops of ridges leaving behind fingerprints and footprints when smooth objects are touched. Table 5.3 Concept 5.4 Skin Color  Skin color Three main pigment producing molecules 1. melanin 2. carotene 3. hemoglobin  Melanin produced by melanocytes number of melanocytes same in most people activity of melanocytes differs exposure to UV light increases production  Carotene precursor of vitamin A vitamin A used to synthesize pigments needed for vision found in stratum corneum and fatty areas of the dermis and hypodermis without melanin and carotene, skin appears translucent European-Americans have pink skin because hemoglobin shows through Accessory Structures of Skin  Hair present on most skin surfaces except palms, palmar surfaces of fingers, soles, and plantar surfaces of toes adults’ hair most heavily distributed on scalp, eyebrows, armpits, and external genitalia genetic and hormonal influences determine thickness and patterns of distribution largely protective functions  Anatomy of Hair composed of columns of dead, keratinized cells bonded together by extracellular proteins shaft is superficial portion transverse section varies – perfectly rounded = straight hair – oval shaped section = wavy hair – kidney shaped section = curly hair  Anatomy of Hair three concentric layers – inner medulla pigment granules and air spaces – middle cortex pigment in dark hair mostly air in gray or white hair – outer cuticle single layer of thin, flat, heavily keratinized cells arranged like shingles on a roof with free edge pointing toward end of hair  Hair Roots hair follicle surrounds root of hair external root sheath – downward continuation of epidermis internal root sheath – produced by matrix dermal root sheath – dense dermis surrounding hair follicle bulb of hair enlarged at root – has germinal layer of cells called matrix sebacous glands associated with follicle arrector pilli muscle makes hair stand on end hair root plexuses – free nerve endings that surround hair follicle making dermis sensitive to hair movement Figure 5.3a Figure 5.3b Figure 5.3c Figure 5.3d  Hair Growth growth stage – matrix cells differentiate, keratinize, and die – forms root sheath and hair shaft – as new cells areise, hair grows longer – scalp hair 2 to 6 years – average 85% of hair in this stage resting stage – old hair is pushed out of follicle – 3 months  Hair Color melanin produced by melanocytes in matrix of hair bulb dark hair has true melanin deposited in cells blond and red hair have melanin variants with more iron and sulfur gray hair has less melanin white hair has air bubbles and no melanin Figure 5.3a Figure 5.3b Figure 5.3c Figure 5.3d  Glands of Skin sebaceous glands – secrete oil onto shaft of hair or surface of skin sudoiferous glands – secrete sweat eccrine or apocrine ceruminous glands – ears mammary glands – breasts  Sebaceous Glands also known as oil glands connected to hair follicles secreting portion in dermis found everywhere except palms and soles secrete sebum – triglycerides, cholesterol, proteins, inorganic salts – keeps skin soft and pliable, prevents excessive water evaporation from skin – inhibits growth of certain skin bacteria  Sudoriferous Glands also known as sweat glands eccrine – most common type – evenly distributed most common on forehead, palms, and soles (up to 450 per square cm) – secrete sweat with water, ions, urea, uric acid, ammonia, amino acids, glucose, and lactic acid – main function is temperature regulation – also mimimal participation in waste elimination  Sudoriferous Glands apocrine sweat glands – less common – found mainly axilla groin areolae bearded region of male faces – secretory portion in hypodermis – opens mainly onto hair follicle – same components as eccrine PLUS lipids and proteins – function begins in puberty – stimulated during emotional stress and sexual excitement  Sudoriferous Glands ceruminous – secrete cerumen (ear wax) – found in external auditory canal – secrete products onto surface of canal or into sebaceous glands in ear – function to provide sticky barrier to impede entrance of foreign bodies into ear Table 5.4  Nails plates of tightly packed, hard, keratinized epidermal cells parts – nail body visible portion appears pink due to underlying blood capillaries lunula near root is white because of thickened matrix – free edge extends past finger or nail body – nail root portion buried in fold of skin at base of nail matrix with mitotic cells here – cuticle stratum corneum Figure 5.4a Figure 5.4b Skin Damage and Repair  Skin Damage and Repair sequence of events that return skin to normal or near normal structure and function epidermal wound healing – epidermis only deep wound healing – when dermis is also damaged  Epidermal Wound Healing injury may extend into dermis but not through it basal cells (stratum basale cells) at edges of wound – break contact with basement membran – enlarge – migrate via mitotic cell division – stop migrating when contact one another contact inhibition – mitosis then replaces other strata Figure 5.5a Figure 5.5b Figure 5.5c Figure 5.5d  Deep Wound Healing injury extends into dermis & hypodermis scar tissue is formed – some normal function lost occurs in four phases 1. inflammatory phase 2. migratory phase 3. proliferative phase 4. maturation phase  Inflammatory Phase blood clot forms loosely uniting wound edges inflammation occurs – eliminates microbes, foreign material, and dying tissue – increases diameter of local blood vessles enhancing delivery of nutrients, immune cells, and fibroblast  Migratory Phase clot dries into scab epithelial cells migrate beneath scab and bridge wound fibroblasts migrate and lay down collagen fibers and glycoproteins in dermis new blood vessels grow tissue called granulation tissue during this phase destined to become scar tissue  Proliferative Phase extensive growth of epithelium deposition of collagen in random patterns by fibroblasts continued growth of blood vessels  Maturation Phase scab sloughs off once epidermis restored to normal thickness granulation tissue developing into scar tissue fibroblasts decrease in number blood vessels restored to normal scar tissue formation called fibrosis – elevated scars called hypertrophic scars – if contained within sight of original wound keloid scars – if extended beyond original wound Figure 5.5a Figure 5.5b Figure 5.5c Figure 5.5d  Concept 5.7 Functions of Skin  Functions of Skin thermoregulation blood storage protection cutaneous sensations excretion and absorption synthesis of calcitrol (vitamin D)  Functions of Skin thermoregulation – regulates body temperature – liberating sweat allowing evaporative cooling of blood increasing blood flow in dermis – reducing flow of blood in dermis when cool to conserve heat blood reservoir – 8 to 10% of total blood flow in resting adults found in dermal blood vessels cutaneous sensations – tactile (touch, pressure, vibration, tickling) – thermal (warmth and coolness) – pain (usually indication of impending or actual tissue damage)  Functions of Skin protection – from invasion by microbes – from abrasion – from heat – from chemicals – from water evaporation through cells – from influx of water through skin – sebum and pH of sweat are antimicrobial – melanin protects from UV radiation – Langerhans cells are active in immunity – macrophages phagocytize bacteria and viruses that manage to penetrate  Functions of Skin excretion and absorption – minor role in eliminating wastes – minor role in absorbing materials from external environment – sweat excretes water, salts, carbon dioxide, ammonia and urea synthesis of calcitrol – most active form of vitamin D – synthesized in response to UV exposure – aids in absorption of calcium from foods End  The Digestive System Gastrointestinal tract (GIT) and the Accessory organs and glands For classroom use only - GBRamos  Laboratory materials Slide samples: ▪ Esophagus Compare the tubular organs ▪ Upper in terms of structure of their layers ▪ lower ▪ Gastroesophageal junction Know the distinguishing ▪ Stomach structural features of the various ▪ Fundus organs ▪ Pylorus ▪ Small intestines Relate structural variations to ▪ Duodenum differences in organ function ▪ Jejunum ▪ Ileum ▪ Large intestine ▪ Recto-anal junction ▪ Appendix  General Histological Features Epithelium 1. Tunica mucosa Lamina propria Muscularis mucosae L 2. Tunica submucosa *Meissner’s plexus Inner 3. Tunica Outer circular muscularis propia / 4. Tunica serosa / longitudinal (Muscularis externa) adventitia *Myenteric plexus/ Auerbach’s plexus For classroom use only - GBRamos  Pharynx Respiratory pharynx oropharynx Superior portion Inferior portion Lined with respiratory epithelium Lined with nonkeratinized stratified squamous epithelium  Esophagus ◼ Characteristic features: ◼ Mucosa lined with nonkeratinized stratified squamous epithelium ◼ Submucosa with esophageal glands (varies as to the segment) ◼ Muscularis externa/propia ▪ Upper portion with skeletal muscles ▪ Middle 3 rd with mixed skeletal and smooth muscle ▪ Lower 3 rd with smooth muscle ◼ Adventitia (except the lowest segment)  Comparison between segments of the Esophagus Points of uppermost Middle 1/3 Lower comparison portion 1/3 1. Muscularis Absent in the Present Present mucosae beginning 2. Tunica Skeletal & smooth Smooth Skeletal muscle muscularis propia/ muscle muscle Muscularis externa Outer Skeletal M. inner smooth M. 3. Submucosal glands Absent few abundant Only Only Only serosa 4. Adventia fibrosa/adventitia fibrosa/adventitia ❖ Presence of glands at transition between middle and lower 1/3 For classroom use only - GBRamos  Skeletal Smooth muscle Esophageal muscle glands Esophageal glands For classroom use only - GBRamos  Stomach Characteristic features: ◼ Mucosa is complex ◼ 2-3 layers muscularis mucosae ◼ Gastric glands ◼ Presence of rugae (gross anatomy) ◼ Muscularis propia/externa ◼ (3 layers) ◼ Inner oblique ◼ Middle circular ◼ Outer longitudinala For classroom use only - GBRamos  Variations in the glands (crypts, pits, ducts) For classroom use only - GBRamos For classroom use only - GBRamos  Esophageal-gastric junction For classroom use only - GBRamos  Closely-packed tubular glands * * * * * * * For classroom use only - GBRamos  Epithelial cell types of the gastric mucosa: ◼ Surface mucous cells ◼ Undifferentiated cells ◼ Neck mucous cells ◼ Parietal/oxyntic cells ◼ Chief/zymogenic cells ◼ Enteroendocrine cells For classroom use only - GBRamos For classroom use only - GBRamos For classroom use only - GBRamos  Small intestine (duodenum, jejunum, ileum) ◼ Characteristic features based on the: ◼ Composition and organization of mucosa ◼ Plicae circularis/ valves of Kerckring ◼ Muscularis propia/externa (2-layered)  Mucosa of the Small intestine: ◼ Presence of villi ◼ Intestinal glands/ Krypts of Lieberkuhn ◼ Enterocytes/absorptive cells ◼ Goblet cells ◼ M cells ◼ Paneth cells ◼ Enteroendocrine cells &Undifferentiated cells For classroom use only - GBRamos  Regional differences Duodenum ◼ Presence of Brunner’s gland in the submucosa ** ◼ Typically with leaflike to * fingerlike villi ◼ Relatively few goblet cells For classroom use only - GBRamos  Jejunum ◼ neither Brunner’s glands nor Peyer’s patches ◼ With long leaflike villi ◼ Many plicae circularis ◼ Intermediate number of goblet cells For classroom use only - GBRamos For classroom use only - GBRamos  Ileum ◼ Lamina propia with many Peyer’s patches ◼ With short, broad-tipped villi ◼ Relatively abundant goblet cells For classroom use only - GBRamos For classroom use only - GBRamos For classroom use only - GBRamos  Large intestine/colon Mucosa ▪ with simple columnar epithelium ▪ Abundant goblet cells ▪ Absence of villi ▪ Deep cyrpts of Lieberkuhn ▪ No mucosal folds except in the recto-anal valves (rectal columns of Morgagni) ▪ No distinct plica circularis Straight tubular glands For classroom use only - GBRamos ◼ Submucosa ◼ Unremarkable except in the lower rectum ◼ Hemorrhoidal plexus of veins (in the lower rectum) For classroom use only - GBRamos  Tunica muscularis propia / Muscularis externa ▪Smooth muscle (longitudinal bands)→ teniae coli Adventitia/Serosa For classroom use only - GBRamos  Anal canal ◼ Mucosa ◼ with short crypts --- disappearing (1st 2 cm) ◼ Stratified squamous epithelium (to the opening)  Submucosa with sebaceous glands and sweat glands Muscularis externa with thickened inner circular smooth muscle For classroom use only - GBRamos  Mucosa fold in the recto-anal valves/junction (Rectal columns of Morgagni) For classroom use only - GBRamos  Appendix ◼ Resembles the colon except for: ▪ relatively small lumen ▪ Fewer and shorter crypts ▪ More lymphoid nodules ▪ Without teniae coli For classroom use only - GBRamos Mucosal types based on function 1. Protective type 2. Secretory type 3. Absorptive type 4. Absorptive / Protective type For classroom use only - GBRamos  The Digestive System Associated glands, organs, and structures of the mouth and buccal cavity Laboratory materials ◼ Salivary glands ◼ Lips ◼ Parotid gland ◼ Tongue ◼ Submandibular ◼ Tooth ◼ Sublingual ◼ Liver ◼ Pancreas ◼ Gall bladder For classroom use only - GBRamos  Accessory glands Gallbladder Salivary glands Pancreas Liver Exocrine glands with plenty of ducts Divided into lobes and lobules subdivided by connective tissue septa ❖ For each exocrine gland, be able to know the primary products and their role in digestion  Important terms to remember ◼ Lobes and lobules ◼ Exocrine secretory cells ▪ Mucous ▪ Serous ◼ Adenomeres (secretory subunits of lobules) ◼ Exocrine Ducts ▪ Intralobular (inside lobules) ▪ Intercalated ▪ Striated ▪ Interlobular (within the septa)  ◼ Acinus/acini/alveoli are smaller secretory subunits 1) mucous 2) serous ◼ Adenomeres: secretory subunits of lobules (All the secretory cells that release their products into a single intralobular duct) (one adenomere = may include one or more acini) For classroom use only - GBRamos For classroom use only - GBRamos  Secretory cells/acini adenomere Mucous: larger; acidophilic cells Serous: relatively small, basophilic foamy/spongy cytoplasm cells granulated cytoplasm serous demilunes: Myoepithelial cells: contractile cells crescent-shaped cap of between basal lamina and epithelial mucous adenomeres cells of adenomeres and ducts For classroom use only - GBRamos  The Salivary glands Be able to differentiate the 3 types in terms of: Content of serous and mucous cells Distribution of serous and mucous cells  Salivary Glands (Parotid, Submaxillary & Submandibular, Sublingual) ◼ Features ◼ Numerous adenomeres ◼ Lobules separated by CT septa ◼ Release secretions thru intercalated, striated and interlobular ducts ◼ Cell types: ◼ Serous & mucous cells (Predominant cells) ◼ Myoepithelial cells ◼ Other cells Antibody-secreting cells in the CT septa  Lobule Lobule For classroom use only - GBRamos  ◼ Parotid gland ◼ Branched acinar gland ◼ Almost exclusively serous ◼ Produce 25 % of the salivary volume ◼ Amylase, sialomucin, For classroom use only - GBRamos  ▪ well-differentiated intercalated and striated ducts are a prominent feature of the parotid glands For classroom use only - GBRamos Submandibular and submaxillary gland ◼ Branched tuboloacinar glands ◼ Both mucous and serous cells (mostly serous) ◼ Produce 70% of the salivary volume ❖ serous demilunes cap mucous adenomeres For classroom use only - GBRamos  Sublingual gland ◼ Branched tuboloalveolar glands ◼ Both mucous and serous cells Serous (mostly mucous) demilunes ◼ Produce 5 % of the salivary volume serous demilunes cap mucous adenomeres For classroom use only - GBRamos For classroom use only - GBRamos  The Pancreas ◼ Serous, compound acinar gland ◼ Without striated ducts ◼ with exocrine and endocrine function ◼ Endocrine portion ◼ (Islets of Langerhans) ◼ Exocrine portion ◼ (pancreatic acinar and centroacinar cells) ❖ Be able to relate the ultrastructure and function of the pancreatic acinar cells For classroom use only - GBRamos  http://www.elsevierimages.com/images/vpv/000/000/034/34535-0550x0475.jpg Pancreatic acinar cells Pyramid-shaped cells with luminal apices Enzyme-secreting cells Trypsin, chymotrypsin (zymogen granules) File:Centroacinar cells.svg http://www.vetmed.vt.edu/education/curriculum/vm8054/labs/Lab20/IMAGES/PANCREASACINI3%20WITH%20LABEL%20copy.jpg Centroacinar cells Duct-lining cells with condensed nucleus and clear cytoplasm Secrete bicarbonate-rich fluid For classroom use only - GBRamos  http://www.ouhsc.edu/histology/Glass%20slides/103_04.jpg For classroom use only - GBRamos  The Liver and the gallbladder A. Be able to describe/know/identify the boundaries and contents of the: Classic liver lobule Portal lobule Hepatic acinus (of Rappaport) B. Be able to understand the liver functions that gave rise to the overlapping views of the functional organization of the liver C. Be able to relate the complex ultrastructure of the hepatocyte to its many function D. Be able to understand the liver’s double blood supply For classroom use only - GBRamos  The Liver Liver capsule/ subserosa liver of gallbladder gallbladder ◼ The largest gland ◼ Glisson’s capsule ◼ Made up of lobules (hepatic lobules) ◼ With dual blood supply (Hepatic PVein & Hepatic Artery) ◼ With 3 drainage system (Hepatic Vein, Lymphatic Vein & Bile Duct) ◼ Hepatocytes For classroom use only - GBRamos  lobule lobule ◼ Marked by the positions of portal triads ◼ Each lobule marked with a central vein ◼ Radiating hepatocyte plates with sinusoids lobule in between lobule hepatocytes http://site.motifolio.com/images/Hepatic-lobule-9111168.png sinusoids Hepatic artery Bile duct Hepatic portal vein Central vein For classroom use only - GBRamos  CV Portal area CV Hepatic lobules with indistinct boundaries in human liver For classroom use only - GBRamos  Hepatocytes are the chief functional cells of the liver ▪ Arranged in cell cords or plates (1-2 cell layers) ▪ Separated by sinusoids ▪ Polygonal shapes with 1-2 nuclei ▪ Granulated (glycogen & lipids) For classroom use only - GBRamos  ◼ Hepatocytes Functions: ❖ metabolism of absorbed nutrients ❖ storage of excess glycogen and lipid ❖ synthesis and secretion of plasma proteins ❖ production and secretion of bile ❖ degradation of metabolic wastes  CV CV Kupffer cells, sinusoids space between sinusoidal endothelium and hepatocytes is called the Space of Disse. For classroom use only - GBRamos  ◼ Hepatic sinusoids ◼ The liver’s blood capillaries ◼ Receive blood from HA & HV (mixed blood flow) ◼ With discontinuous endothelial walls ◼ Lined with Kuppfer cells ◼ Space of Disse (between endothelium and hepatocytes) ❖ Space of Disse serve as the liver’s lymphatic capillaries  Hepatic portal triad ◼ Occupies a portal space at each corner of a lobule ◼ 3 components ◼ Portal venule/portal vein ◼ Portal arteriole/portal artery ◼ Bile ductule/ducta For classroom use only - GBRamos  Blood supply of the liver ◼ Hepatic portal vein ◼ Supplies 75% of liver’s total blood volume ◼ Formed by the junction of mesenteric and splenic veins Intestinal Oxygen poor; Nutrient-rich Mesenteric capillaries veins Oxygen poor; Nutrient-rich By-product of blood destruction By-product of Hepatic portal vein Splenic blood destruction Splenic sinusoids veins LIVER sinusoids  Hepatic Artery ◼ Supplies about 25% of liver’s blood volume ◼ A branch of the celiac artery ◼ Empties oxygen-rich blood into the sinusoids Oxygen-rich blood Hepatic artery Liver sinusoids Hepatic portal vein Oxygen poor; Nutrient-rich By-product of blood destruction  Blood supply and drainage system 1) Hepatic portal vein 2) Hepatic artery 3) Bile duct Oxygen-poor blood; Oxygen-rich Nutrient-rich blood Bile canaliculi Space Hepatic duct Liver of Disse sinusoids 4) Central vein Common bile duct Sublobular vein Larger hepatic vein Inferior vena cava  Liver histoarchitecture and its functions ◼ Three models: 1. Classic lobule 1 2 2. Portal lobule 3. Hepatic acinus (of Rappaport) 3 For classroom use only - GBRamos Figure 4. Classic (hepatic) lobule with PTs at the periphery of the lobule and CV in the center of the lobule. The PTs and CV are evenly spaced throughout the hepatic parenchyma. Blood flows from the PTs to the CV (red arrow), while bile flows in the opposite direction (green arrow). The acinus is represented by the thicker curved lines and is composed of zones 1-3. (H&E  Classic lobule ◼ Based on the direction of blood flow http://www.siumed.edu/~dking2/erg/images/hlob.gif Blood flow from the portal vessels → sinusoids → central vein For classroom use only - GBRamos  Portal lobule ◼ Based on the direction of bile flow Bile flow from the: hepatocytes → sinusoids → space of Disse→ → bile canaliculi →bile duct of the triads For classroom use only - GBRamos  Hepatic acinus (of Rappaport) ◼ Based on the content of oxgen, nutrients and toxins Zones distributed depending on their distance from the distributing vessel; with Zone 1 having the highest concentration of toxins and nutrients For classroom use only - GBRamos  The gallbladder (Blind-ending sac at the lower surface of liver) A. Be able to describe/understand the structure, function, and location of the gallbladder B. From the photomicrographs, identify a gallbladder and distinguish it from a similar section of the small intestine  ◼ The gallbladder/ Cholecyst Function: Stores and concentrates bile Hollow organ with layered walls; Without definitive submucosa With Branched mucosal folds Presence of sinuses (large lumens) For classroom use only - GBRamos ◼ Mucosa ◼ Consists of simple columnar epithelium ◼ Deep invaginations forming the glands ◼ With large sinuses ◼ Muscularis ◼ Interwoven smooth muscle fibers ◼ Adventitia and serosa ◼ Outer layer consists of adventitia that attaches to the liver ◼ Serosa covers its peritoneal surface  The Lips Vermilion border - transition zone of the lip and the oral mucosa devoid of sweat and sebaceous glands Upper lip: from the base of the nose superiorly → nasolabial folds laterally → free edge of the vermilion border inferiorly. Lower lip: from the superior free vermilion edge superiorly→ commissures laterally → the mandible inferiorly. For classroom use only - GBRamos  Tongue muscular organ covered with mucosa (interlacing bundles of skeletal muscle)aa ▪ sulcus terminalis groove that divides the tongue into an anterior 2/3 and a posterior 1/3. ▪ Anterior 2/3 of mucosa is formed into papillae For classroom use only - GBRamos  For 15-5 Figure classroom use only - GBRamos Copyright © McGraw-Hill Companies  Types of papillae: 1. Filiform short bristles most numerous type heavily keratinized projections For classroom use only - GBRamos  2. Fungiform more globular than filiform with thin, non-keratinized epithelium with richly vascularized core of supporting CT For classroom use only - GBRamos  3. Circumvallate contain most of the taste buds largest and least common type surrounded by deep clefts associated with von Ebner’s glands ❖ Foliate is rudimentary in human; found in some animal species For classroom use only - GBRamos  The Respiratory System (the Lungs & the Airways) Upper respiratory tract nasal cavities to nasopharynx Lower respiratory tract larynx to respiratory bronchioles For classroom use only – Ramos, Ples, Uba, Cantiller  The Respiratory System (the Lungs & the Airways) Laboratory materials Nasal cavities with olfactory epithelium Trachea Bronchus Larynx Epiglottis Bronchiole Lungs - bronchi - bronchioles - terminal & respiratory For classroom use only – Ramos, Ples, Uba, Cantiller  PreLab Instructions: 1. Be able to describe the respiratory tract in terms of: arrangement, composition, function of component layers 2. Describe function of the cells in each layer 3. Compare/contrast different parts of the respiratory tract ; take note of the differences in wall structure 4. Give attention to/understand the: - structure of the inter-alveolar septum - structure and function of the blood-air barrier 5. From the photomicrographs of the respiratory tract and the lung tissues: - distinguish the various components, - identify the cell types - identify the organ/tissues For classroom use only – Ramos, Ples, Uba, Cantiller  Wall of the respiratory tract ▪ With epithelial lining ▪ With lamina propia ▪ With smooth muscle Epithelial lining respiratory epithelium → ciliated pseudostratified columnar epith. ❖ gradual transition in cell height and loses goblet cells ▪ Epithelial cell types: ciliated columnar cells mucous goblet cells brush cells basal cells small granule cells For classroom use only – Ramos, Ples, Uba, Cantiller  Lamina propia consisting of: connective tissues mucous glands (in the upper tract) Elastic fiber Cartilage bone ❖ Gradually decreases –→ disappearing at the level of bronchioles Smooth muscle begins in the trachea → to many layers in the bronchi ❖ Gradually decreases in thickness from bronchi → disappearing at the level of alveolar ducts  Bronchial Tree For classroom use only – Ramos, Ples, Uba, Cantiller  Functional Divisions of the RS Ventilating Conducting Respiratory mechanism Portion Portion Diaphragm Nasal cavity ❖ End of bronchial tree Rib cage Intercostal muscles Nasopharynx Respiratory bronchioles Abdominal muscles Larynx Alveolar ducts Elastic tissues in the Trachea Alveolar sacs lungs Bronchi Bronchioles Terminal bronchioles  Nasal cavity Nasopharynx Larynx Trachea Bronchi Bronchioles Terminal bronchioles Respiratory bronchioles Alveolar ducts Alveolar sacs For classroom use only – Ramos, Ples, Uba, Cantiller  Nasal cavity ◼ 2 cavities → Divided by nasal septum ◼ Each cavity with 2 chambers: Vestibule (anterior, smaller, wider) Nasal fossa (posterior, larger, narrower) For classroom use only – Ramos, Ples, Uba, Cantiller  Vestibule (anterior, smaller, wider) ▪ Lined by keratinized to non-keratinized stratified squamous → transition to respiratory epithelium ▪ Bowman’s glands in the lamina propia ▪ With short hair (vibrissae) Nasal fossa (posterior, larger, narrower) ◼ Lined by respiratory epithelium ◼ Venous sinuses and Bowman's glands in the lamina propia ◼ Supported by bones ❖ Specialized olfactory epithelium in the roof of each fossa with receptors of smell (fila olfactoria) For classroom use only – Ramos, Ples, Uba, Cantiller  NS - nasal septum NC – nasal chamber T – turbinate bones (conchae) PS – paranasal sinuses ACF – anterior cranial fossa For classroom use only – Ramos, Ples, Uba, Cantiller  Naso-pharynx ◼ Upper part of the pharynx; overlying the soft palate ◼ Lined by respiratory epithelium ◼ Lamina propia contains: ◼ lymphoid nodules ◼ mucous ◼ serous glands ◼ With skeletal muscles  Larynx Lies between base of and trachea ◼ Opening protected by epiglottis ◼ Walls supported by laryngeal cartilages ◼ Skeletal muscles around cartilages ▪ Houses the vocal apparatus ▪ Epithelium varies according to location respiratory epithelium stratified squamous epithelium FF/vestibular fold/upper fold TF/vocal fold/lower fold Larynx:TF=true vocal folds; SG= subglottis For classroom use only – space; FF= false vocal folds; & V=ventricle of Morgani Ramos, Ples, Uba, Cantiller For classroom use only – Ramos, Ples, Uba, Cantiller  Trachea ◼ Lined by respiratory epithelium ◼ Lamina propia with ◼ Mixed serousmucous glands ◼ Presence of C-shaped cartilages ◼ With fibroelastic ligament and smooth muscle (trachealis muscle) For classroom use only – Ramos, Ples, Uba, Cantiller  Wall structure: ◼ With epithelium ◼ With lamina propria ◼ With cartilage ◼ With smooth muscle ◼ Adventitia ❖ each layer undergoes gradual change in thickness For classroom use only – Ramos, Ples, Uba, Cantiller  Trachea Tracheal mucosa, submucosa, cartilage, and adventita For classroom use only – Ramos, Ples, Uba, Cantiller  Presence of cartilage islands/plates INSTEAD of C-shaped cartilages For classroom use only – Ramos, Ples, Uba, Cantiller  Bronchioles ▪ Lined by simple columnar with cilia and Clara cells ▪ (replace the goblet cells) ▪ Lamina propia without glands ▪ Each bronchiole-→ 5-7 terminal bronchioles For classroom use only – Ramos, Ples, Uba, Cantiller  Terminal bronchioles (without cartilage support) ◼ Smallest component of the conducting portion ◼ Lined by ciliated cuboidal or columnar epithelium ◼ With cilia ◼ With goblet cells ◼ With Clara cells ◼ each terminal bronchiole → 2 + respiratory bronchiole For classroom use only – Ramos, Ples, Uba, Cantiller  Respiratory portion ◼ Respiratory bronchiole ◼ Lined by cuboidal epithelium, interrupted by alveoli ◼ Alveolar ducts ◼ Extensions of Rb, with alveoli almost entirely lining the walls ◼ Alveolar atria and sacs ◼ Distal terminations of alveolar ducts For classroom use only – Ramos, Ples, Uba, Cantiller  Respiratory bronchiole surrounded by alveoli For classroom use only – Ramos & Ples  The Alveoli 1. Alveoli are lined by simple squamous epithelium For classroom use only – Ramos, Ples, Uba, Cantiller  The Alveoli For classroom use only – Ramos, Ples, Uba, Cantiller  2. The alveoli are connected by interalveolar septum. 1. Specialized for gas exchange 2. Consists of non-fenestrated capillaries For classroom use only – Ramos, Ples, Uba, Cantiller  3. Alveolus with: - alveolar type II cell (type II pneumocyte) that secretes surfactant - capillaries that form the blood-air barrier For classroom use only – Ramos, Ples, Uba, Cantiller  ◼ Blood-air barrier: ◼ Layers: ◼ Film of pulmonary surfactant ◼ Cytoplasm of simple squamous cells ◼ Fused basal laminae between Type I alveolar cells and endothelial cells ▪ Alveolar cell types: ◼ Type I cells ▪ Alveolar type I cells/Type I ▪ pneumocytes/Squamous alveolar cells ▪ Make up 97% of alveolar surfaces ▪ Specialized to serve as blood-air barrier ◼ Type II ▪ Type II alveolar cells/type II pneumocytes/great alveolar cells/alveolar septal cells ▪ Cover remaining 3% of alveolar surfaces ▪ Secretory cells ▪ Pulmonary surfactants ◼ Alveolar macrophages ▪ Dust cells ▪ Monocyte-derived (MPS) ▪ Found on the surface of alveolar septa and in the interstitium ▪ Removes debris that escape the mucos and cilia in the conducting portion ▪ Phagocytose blood cells that enter the alveoli due to heart failure  Alveolar Duct Showing the passage of Alveolus with alveolar type II cell air into the alveolus (type II pneumocyte) that secretes surfactant and capillaries that form the blood-air barrier. For classroom use only – Ramos, Ples, Uba, Cantiller