Chapter 5 Histology microscopic anatomy 1 Ch 5

Chapter 5 -- Histology (microscopic anatomy) 1

Ch. 5 Study Guide 1. Read Chapter 5 up to page 170 right before 5. 4 Nervous and Muscular Tissue 2. Comprehend Terminology (those in bold in the textbook) 3. Study-- Figure questions, Think About It questions, and Before You Go On (sectionending) questions 4. Do end-of-chapter questions ü Testing Your Recall— 1 -4, 6 -10, 13, 17, 18, 20 ü True or False– 1, 2, 5, 6, 10 ü Testing Your Comprehension-- #4, #5 2

5. 1 --The study of tissues 3

§ The Study of Tissues 1. Whole body contains only 200 different types of cells 2. Four tissue classes (Def. of tissue--? ) See Table 5. 1. 3. Histology (microscopic anatomy) – study of tissues and how they form organs 4. Organ = structure with discrete boundaries – composed of 2 or more tissue types – Examples: 4

§ Differences among 4 Tissue Classes 1. Types and functions of cells- • For example: Epithelial, CT, Nervous, Muscular 2. Characteristics of the matrix (extracellular material) • Rubbery, stony, or gelatinous 3. Relative amount of space occupied by cells versus matrix • CT vs. muscle and epithelium 5

§ Embryonic Tissues 1. Embryo begins as a single cell – divides into many cells that form layers (strata) 2. Three primary germ layers A. ectoderm (outer) gives rise to: epidermis + nervous system B. endoderm (inner): mucous membranes: GI tract and respiratory linings; digestive glands. C. mesoderm (middle) forms mesenchyme (gelatinuous tissue) and then give rise to muscle, bone, and blood 6

§ Tissue Sectioning (1) 1. Preparation of histological specimens – fixation – sections – mounted on slides & stained 2. Sectioning (slicing) an organ or tissue reduces a 3 -dimensional structure to a 2 dimensional slice (see the next 3 slides) 7

Tissue Sectioning (2) 1 2 3 4 5 1 2 • Slices 1 & 5 miss the yolk / cell nucleus 5 3 4 • Cell nucleus is smaller in sections 2 & 4 8

Tissue Sectioning (3) A B • Image A is a cross section of elbow macaroni, resembling a blood vessel, piece of gut, or other tubular organ. • Image B is a longitudinal section of a sweat gland. Notice what a single slice could look like 9

§ Types of Tissue Sections (1) • Longitudinal section – tissue cut along the longest direction of an organ • Cross section – tissue cut perpendicular to the length of an organ • Oblique section – tissue cut at an angle between a cross & longitudinal section 10

Types of Tissue Sections (2) Practice at home. • Would you classify the egg sections as longitudinal, cross, or oblique sections? • How would the egg look if sectioned in the other two planes? (Fig. 5. 2 question) 11

5. 2 --Epithelial tissue 12

§ Epithelial Tissue Introduction (1) 1. One or more layers of closely adhering cells 2. (Top) Forms a flat sheet with the upper (______) surface exposed to the environment or an internal body cavity 3. (Bottom) Sits on basement membrane (basal surface of cells); Fig. X – anchors epithelium to underlying connective tissue 4. (Nourishment) No room for blood vessels; . . . CT 13

What are the functions of the basement membrane? 14

§ Epithelial Tissue Introduction (2) Arrangement and Cell Shape— 1. Simple epithelium – contains one layer of cells – named by shape of cells 2. Stratified epithelium – contains more than one layer – named by shape of apical cells Fig. 5. 3 15

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§ 1. Simple Squamous Epithelium— 17

1. (Structure) Single row of flat cells (scaly) 2. (Functions) Allows rapid diffusion of substances; secretes serous fluid 3. (Locations) in alveoli, glomerular capsule, endothelium (blood vessels and heart), and serosa (external surface) such as stomach & intestines 18

§ 2. Simple Cuboidal Epithelium— 1. (Structure) Single row of cube-shaped cells, often with microvilli 2. (Functions) Absorption & secretion; produces mucus 3. (Locations) Liver, thyroid, mammary, salivary and other glands, bronchioles, and most kidney tubules Fig. 5. 5 19

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§ 3. Simple Columnar Epithelium— 1. (Structure) Single row of tall, narrow cells – vertically oriented, oval nuclei in basal half of cell 2. (Functions) Absorption & secretion; secretion of mucus 3. (Locations) Inner lining of GI tract from stomach to the anus; ducts of gallbladder; uterus, and uterine tubes; some kidney tubes; a few portions of upper respiratory tract 21

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§ 4. Pseudostratified Epithelium— 1. (Structure) Single row of cells not all of which reach the free surface; nuclei at different levels. 2. (Functions) secretes propels mucus 3. (Locations) most of the upper respiratory system from nasal cavity to bronchi; part of male urethra Fig. 5. 7 23

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§ Stratified Epithelia • Composed of more than one layer of cells & named for shape of _____ cells • Deepest cells sit on basement membrane 25

§ 5 A. Keratinized Stratified Squamous Fig. 5. 8 Skin from the sole of the foot • Layers of epithelium covered with compact, ______ squamous cells (no nuclei) packed with protein keratin • Retards water loss, prevents entrance of organisms • Forms epidermal layer of skin (esp. soles and palms) 26

§ 5 B. Nonkeratinized Stratified Squamous Epithelial layer Fig. 5. 9 Mucosa of the vagina • Multilayered epithelium that lacks surface layer of dead cells forming moist, slippery layer • Locations: tongue, oral mucosa, esophagus & vagina 27

Pap smear/test • • What? Examination of exfoliated cells Where? The cervix Why? How? Loose cells are examined microscopically for abnormal cells • Who? Between 30 -50 years old Fig. 28. 5 28

Fig. 28. 5—Pap smears Which one is normal cells? 29

§ 6. Stratified Cuboidal Epithelium Fig. 5. 10—Sweat gland ducts • (Structure) Two or more layers of cells; surface cells square or round • (Functions) Secretion and production • (Locations) Sweat glands, mammary glands, salivary glands, ovarian follicles, seminiferous tubules 30

§ 7. Transitional Epithelium 1. (Structure) Multilayered epithelium with rounded (not flattened) surface cells 2. (Functions) Allow stretches and distension 3. (Locations) Urinary tract--part of kidney, ureter, urinary bladder, part of the urethra Fig. X 31

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Qs from Before You Go On (p. 162) üDistinguish between simple and stratified epithelia. Explain why pseudostratified columnar epithelium belongs in the former category? üDistinguish a stratified squamous epithelium from a transitional epithelium. üHow do the epithelia of the esophagus and stomach differ? Respective functions? 33

5. 3 --Connective tissue 34

§ Connective Tissue (CT) Overview • Most abundant and variable tissue type • 3 structural elements – – Consists mostly of (a) G____; (b) F_______ – (c) with widely spaced cells • Functions of CT: – Binding of organs --Ex. a tendon connects muscle to bone – Support, protection, movement -- Ex. bones – Storage – (energy, electrolytes) Ex. Fats/bones – Transport -- Ex. Blood 35

§ 1. Ground Substance of C. T. • Gelatinous or rubbery material found in between cells – Function? • Consists of 3 classes of large molecules – Glycosaminoglycans (GAGs) – • Polysacharides that attract sodium & hold water • Ex. -- – Proteoglycan is bottlebrush-shaped molecule • Forms thick gel that slows the spread of pathogens – Cell adhesive glycoproteins • Allow themselves bind to matrix elements 36

§ 2. Fibers of C. T. • Collagen fibers--called white fibers (Fig. 5. 13) – Most abundant protein of the body – Thick, tough, resist stretch yet flexible – Ex. tendons, ligaments & dermis • Elastic fibers--called yellow fibers – made of E______; recoil like rubberband (elasticity) – Ex. skin, lungs & arteries; ability to recoil • Reticular fibers – Thin collagen fibers coated with glycoprotein – Ex. form framework for spleen & lymph nodes 37

Collagen Tendons (collagen) Figure 5. 13

§ 3. Cells of C. T. • Fibroblasts -- produce fibers & ground substance • WBCs -- wander (mostly in CT) in search of bacteria – Macrophages – large phagocytic cells-- arise from monocytes (WBC); function? phagocytosis – Plasma cells -- arise from lymphocytes; antibodyproducing cells • Mast cells – oval shaped; clustered along blood vessels; secrete heparin and histamine • Adipocytes or fat cells --store triglycerides 39

5. 3 --Connective tissue A. Fibrous CT 40

§ Five Types of Fibrous C. T. Divided into 2 broad categories: • Loose CT (3 slides followed) – contains MORE gel-like ground substance between cells – 3 types: A--areolar, B--reticular, C--adipose tissue • Dense CT (2 slides followed) – FIBERS fill the spaces between cells – 2 types varying in fiber orientation: D--dense regular, E--dense irregular 41

§ A-- Areolar Tissue Fig. Mesentery • Loose arrangement of collagenous and elastic fibers; scattered cell types; abundant ground substance • Locations-- Underlying all epithelia; surrounding 42 nerves, blood vessels, esophagus, trachea

§ B-- Reticular Tissue • Loose network of R_____ and cells • Forms structural supportive stroma for lymphatic organs • Locations-- lymph nodes, spleen, thymus & bone marrow Fig. Spleen 43

§ C-- Adipose Tissue (Fat) • Large, empty-looking cells dominate with thin margins; nucleus pressed against cell membrane; often very pale • Functions-- Energy storage, insulation, space filled as cushioning • Locations-- Subcutaneous fat beneath skin, breast, heart surface, surrounding organs Fig. 5. 18 44

Figure 5. 16 b Fig. Adipose tissue 45

§ D-- Dense Regular CT • Structure-- Mainly densely, PACKED, PARALLEL C_____FIBERS; compressed fibroblast nuclei; scanty open space and blood vessels • Locations-- Tendons & ligaments Figure 5. 16 46

D-- Dense Regular CT Fig. Tendon 47

§ E-- Dense Irregular CT • Densely packed collagen fibers running in ____ directions; scanty open space; few visible cells and blood vessels • Function-- Withstands stresses applied in MANY DIFFERENT DIRECTIONS • Locations-- Deeper portion of skin; capsules around organs (ex. Liver, kidney etc); sheaths around cartilages and bones Figure 5. 17 48

E-- Dense Irregular CT Fig. Dermis of the skin 49

5. 3 --Connective tissue B. Cartilage, Bone, Blood 50

§ Cartilage • Supportive CT with rubbery matrix • Chondroblasts produce matrix, surround themselves, and become Chondrocytes • No blood vessels; so diffusion must bring in nutrients & remove wastes; healing. . . • 3 types of cartilage depend upon FIBER TYPES – A--hyaline, B--elastic, and C--fibrocartilage 51

§ A-- Hyaline Cartilage • Clear, glassy matrix; invisible fine dispersed collagen fibers; chondrocytes in small clusters enclosed in lacunae • Supports airway, eases joint movements • Locations-- Over ends of bones at movable joints; sternal ends of ribs; supportive material in larynx, trachea, bronchi and fetal skeleton Fig. 5. 19 52

Figure 5. 19 b Fig. Fetal skeleton 53

§ B-- Elastic Cartilage • Hyaline cartilage with weblike mesh of elastic fibers amid the lacunae; always has perichondrium (a sheath of C. T. ) • Provides flexible, elastic support • Locations— Ear + Epiglottis • Fig. 5. 20 54

Figure 5. 20 b Fig. External ear 55

§ C-- Fibrocartilage • Cartilage containing extensive parallel Collagen fibers; never has perichondrium; row of chondrocytes in lacunae • Resists compression and absorbs shock in some joints • Locations-- Pubic symphysis, menisci (pads) in knee joint, & intervertebral discs Fig. 5. 21 56

Figure 5. 21 b Fig. Intervertebral disc 57

§ Bone (osseous tissue) • Spongy bone looks spongy in appearance – fills heads of long bones – delicate struts of bone – ALWAYS COVERED BY COMPACT BONE • Compact (dense) bone looks solid – No space visible to the naked eye – External surfaces of ALL bones 58

§ Compact bone • Calcified matrix in concentric lamellae around central (haversian) canal containing blood vessels • osteocytes in lacunae between lamellae connected by canaliculi— delicate narrowing canals. . . • Physical support; leverage for muscles; mineral storage • Locations-- in skeleton (Fig. 5. 22) 59

Canaliculi ? Fig. Compact bone 60

§ Blood • Variety of cells and cell fragments; some with nuclei & some without • RBC, WBC, platelets • Found in heart and blood vessels Fig. 5. 23 61

Fig. Blood smear 62