McGraw-Hill Education. Chapter 05 Histology

Transcription

1 Chapter 05 Histology

2 Ch. 5 Part 1: 5-1 & 5-2 Into To Tissues & Epithelial Tissue (pgs )

3 Cells are Organized into Tissues In complex organisms, cells are organized into tissues Tissues: Groups of similar cells with a common function The study of tissues is called histology. There are 4 major types of tissues in the body: 1. Epithelial tissue 2. Connective tissue 3. Muscle tissue 4. Nervous tissue

4 Table Major Tissue Types Type Function Location Distinguishing Characteristics Epithelial Connective Protection, secretion, absorption, excretion Bind, support, protect, fill spaces, store fat, produce blood cells Cover body surface, cover and line internal organs, compose glands Widely distributed throughout the body Muscle Movement Attached to bones, in the walls of hollow internal organs, heart Nervous Conduct impulses for coordination, regulation, integration, and sensory reception Brain, spinal cord, nerves Lack blood vessels, cells readily divide, cells are tightly packed Mostly have good blood supply, cells are farther apart than epithelial cells, with extracellular matrix in between Able to contract in response to specific stimuli Cells communicate with each other and other body parts

5 Figure 5.1 Intercellular Junctions Tight junctions: Membranes of adjacent cells merge and fuse Located among cells that form linings, sheet-like layers Blood-brain barrier Desmosomes: Form spot welds between cells Structural reinforcement Located among outer skin cells Gap junctions: Tubular channels between cells Molecules can move between cells Located in cardiac muscle cells

6 Table 5.1 Types of Intercellular Junctions Type Characteristics Example Tight junctions Desmosomes Gap junction Close space between cells by fusing cell membranes Bind cells by forming spot welds between cell membranes Form tubular channels between cells that allow exchange of substances Cells that line the small intestine Cells of the outer skin layer Muscle cells of the heart and digestive tract

7 From Science to Technology 5.1 Nanotechnology Meets the Blood-Brain Barrier Nanotechnology helps with drug delivery across the blood-brain barrier Blood-brain barrier selects which chemicals are allowed to cross; protects from toxins & chemical fluctuations Nanotechnology uses structures smaller than 100 nm in at least 1 direction, to help medications cross the barrier Example: Anesthetics or chemotherapeutics are combined with liposomes (phospholipid bubbles) to mask portion of drug that cannot cross the barrier Example: Insulin can be inhaled in nanoparticles, instead of being injected

8 General Characteristics: Covers organs and body surface Lines cavities and hollow organs Makes up glands Epithelial Tissue Have a free surface on outside, and basement membrane on inside This tissue lacks blood vessels (avascular) and nutrients diffuse to epithelial tissue from underlying connective tissue Cells readily divide; injuries heal rapidly Cells are tightly packed Classified according to cell shape and number of cell layers Shapes: squamous (flat), cuboidal (cube-shaped), columnar (tall) Layers: simple (one layer of cells), stratified (2 or more layer of cells), or pseudostratified (appears layered, but is not) McGraw-Hill Education

9 Figures 5.3 and 5.4 Epithelial Tissue Types Simple squamous: Single layer of thin, flat cells Substances pass easily through air sacs (alveoli) & capillaries Thin & delicate, can be damaged Found in diffusion & filtration sites Lines air sacs (alveoli) & capillaries Lines blood & lymphatic vessels Simple cuboidal: Single layer of cube-shaped cells Secretion and absorption Lines kidney tubules, thyroid follicles Covers ovaries Lines ducts of some glands McGraw-Hill Education Top: b-c: McGraw-Hill Education/Al Telser, photographer. Bottom: b: Victor P. Eroschenko

10 Figures 5.5 and 5.7 Epithelial Tissue Types Simple columnar: Single layer of elongated cells Nuclei usually at same level, near basement membrane Sometimes have cilia Sometimes have microvilli Sometimes have goblet cells (secrete mucus) Secretion and absorption Lines uterus, stomach, intestines Pseudostratified columnar: Single layer, but appears layered Nuclei at 2 or more levels Cells vary in shape Often has cilia, goblet cells Protection from infection Lines respiratory passageways McGraw-Hill Education Top: b: Victor P. Eroschenko Bottom: McGraw-Hill Education/Dennis Strete

11 Figures 5.8 and 5.9 Epithelial Tissue Types Stratified squamous: Many cell layers; thick Protective layer Outermost cells are flat Deeper cells are cuboidal New cells form, push older cells toward free surface Outer layer of skin (keratinized) Lines oral cavity, vagina, anal canal Stratified cuboidal: 2-3 layers of cube-shaped cells More protection than 1 layer Lines ducts of mammary, sweat, & salivary glands, and pancreas McGraw-Hill Education Top: McGraw-Hill Education/Al Telser, photographer Bottom: McGraw-Hill Education/Al Telser, photographer

12 Figures 5.10 and 5.11 Epithelial Tissue Types Stratified columnar: Top layer of elongated cells Cube-shaped cells in deeper layers Lines part of male urethra, ducts of exocrine glands Transitional (uroepithelium): Many cell layers Cube-shaped and elongated cells Changes shape with increased tension; stretches Line urinary bladder, ureters, and part of urethra McGraw-Hill Education Top: b: McGraw-Hill Education/Al Telser, photographer Bottom: b,d: Ed Reschke

13 Glandular Epithelium Glandular Epithelium: Composed of cells that produce and secrete substances into ducts or body fluids There are 2 types of glands: Endocrine glands secrete into tissue fluid or blood Exocrine glands secrete into ducts that open onto surface 2 structural types of exocrine glands: Unicellular: Composed of one cell, such as a goblet cell (secretes mucus) Multicellular: Composed of many cells Sweat glands, salivary glands, etc. Simple or compound

14 Figure 5.12 Structural Types of Exocrine Glands Simple: duct does not branch Compound: duct branches before it reaches secretory portion Tubular: consist of epithelial-lined tubes Alveolar: terminal portions form sac-like dilations

15 Table 5.3 Types of Exocrine Glands Type Characteristics Example Unicellular A single secretory cell Mucous-secreting cell (see Fig. 5.5) Multicellular Simple glands Glands that consist of many cells Glands that communicate with the surface by means of ducts that do not branch before reaching the secretory portion 1. Simple tubular gland Straight tube-like gland that opens directly onto surface Intestinal glands of small intestine (see Fig. 17.3) 2. Simple branched tubular gland Branched, tube-like gland; duct short or absent Gastric glands (see Fig ) 3. Simple coiled tubular gland Long, coiled, tube-like gland; long duct Merocrine (sweat) glands of skin (see Figs and 6.11) 4. Simple branched alveolar gland Secretory portions of gland expand into saclike compartments along duct Compound glands Glands that communicate with surface by means of ducts that branch repeatedly before reaching the secretory portion 1. Compound tubular gland Secretory portions are tubules extending from branches of branches that combine into one duct 2. Compound alveolar gland Secretory portions are irregularly branched tubules with numerous saclike outgrowths Sebaceous gland of skin (see Fig. 5.14) Bulbourethral glands of male (see Fig. 22.4) Mammary glands (see Fig )

16 Figure 5.13 Types of Glandular Secretion Merocrine glands: Secrete fluid products by exocytosis; salivary & sweat glands, pancreas Apocrine glands: Lose small part of cell during secretion; mammary & ceruminous glands Holocrine glands: Release entire cells filled with product; sebaceous glands

17 Table 5.5 Epithelial Tissues Type Description Function Location Simple squamous epithelium Single layer, flattened cells Filtration, diffusion, osmosis, covers surface Air sacs of lungs, walls of capillaries, linings of blood and lymph vessels, part of the membranes lining body cavities and covering viscera Simple cuboidal epithelium Single layer, cube-shaped cells Protection, secretion, absorption Surface of ovaries, linings of kidney tubules, and linings of ducts of certain glands Simple columnar epithelium Single layer, elongated cells Protection, secretion, absorption Linings of uterus, stomach, and intestines Pseudostratified columnar epithelium Single layer, elongated cells Protection, secretion, movement of mucus and substances Linings of respiratory passages Stratified squamous epithelium Many layers, top cells flattened Protection Superficial layer of skin and linings of oral cavity, vagina, and anal canal Stratified cuboidal epithelium 2 or 3 layers, cube-shaped cells Protection Linings of ducts of mammary glands, sweat glands, salivary glands, and pancreas Stratified columnar epithelium Top layer of elongated cells, lower layers of cube-shaped cells Protection, secretion Part of the male urethra and lining of larger ducts of excretory glands Transitional epithelium Many layers of cubeshaped and elongated cells Stretchability, protection Inner lining of urinary bladder and linings of ureters and part of urethra Glandular epithelium Unicellular or multicellular Secretion Salivary glands, sweat glands, endocrine glands

18 Ch. 5 Part 2: 5-3 Connective Tissue (pgs )

19 Connective Tissues General characteristics: Most abundant tissue type Cells are farther apart than epithelial cells; contain matrix between cells Many functions: Bind structures together Provide support and protection Serve as frameworks Fill spaces Store fat Produce blood cells Protect against infections Help repair tissue damage Extracellular matrix consists of protein fibers and ground substance; consistency varies from fluid to semisolid to solid Most have good blood supply, and are well-nourished, but vascularity varies among tissue types Most cells can divide

20 Clinical Application 5.1 The Body s Glue: The Extracellular Matrix Functions of normal extracellular matrix (ECM): scaffolding that organizes & anchors cells into tissues relays chemical signals that control cell division and differentiation, tissue repair, cell migration Cancer: Can convert fibroblasts into myofibroblasts, which take on characteristics of cancer cells; also loosens fibroblast connections, allowing migration of converted fibroblasts and spreading cancer Liver Fibrosis: Collagen deposition increases, and ECM now exceeds its normal 3% of organ. Damaging agents evoke normal inflammatory response, but if it continues too long, it can block connection between liver cells and blood, perhaps leading to cirrhosis. Heart Failure and Atherosclerosis: Some forms involve excess collagen deposition, which can stiffen the heart or block blood flow

21 Figures 5.15 and 5.16 Major Cell Types of Connective Tissue Fibroblasts: Most common fixed cell Large star-shaped cell Secrete fibers into extracellular matrix Macrophages (Histiocytes): Usually attached to fibers, but can detach and wander Conduct phagocytosis Defend against infection McGraw-Hill Education Top: Juergen Berger/Science Source Bottom: Biology Pics/Science Source

22 Figures 5.17 Major Cell Types of Connective Tissue Mast Cells: Large cells Release heparin to prevent blood clotting Release histamine, which causes inflammatory response McGraw-Hill Education Steve Gschmeissner/Science Source

23 Figure 5.18 Connective Tissue Fibers Fibroblasts produce 3 types of fibers in connective tissue: 1. Collagen Fibers: Thick threads of collagen, the body s main structural protein Great tensile strength and flexible, slightly elastic Found in ligaments and tendons 2. Elastic (Yellow) Fibers: Composed of elastin protein; branching Can stretch and return to original shape Not as strong as collagen fibers Found in vocal cords, respiratory air passages 3. Reticular Fibers: Thin, branching fibers of collagen Form delicate, supporting networks Found in spleen, liver McGraw-Hill Education Prof. P. Motta/Univ. La Sapienza /Science Source

24 Table 5.6 Components of Connective Tissue Component Characteristics Function Cellular Fibroblasts Widely distributed, large, star-shaped cells Secrete proteins that become fibers Macrophages Motile cells sometimes attached to fibers Clear foreign particles from tissues by phagocytosis Mast cells Extracellular Matrix Collagen fibers (white fibers) Elastic fibers (yellow fibers) Large cells, usually located near blood vessels Thick, threadlike fibers of collagen with great tensile strength Bundles of microfibrils embedded in elastin Release substances that may help prevent blood clotting (heparin) and promote inflammation (histamine) Hold structures together Provide elastic quality to parts that stretch Reticular fibers Thin fibers of collagen Form delicate supportive networks within tissues Ground substance Nonfibrous protein and other molecules, and varying amounts of fluid Fills in spaces around cells and fibers

25 Clinical Application 5.2 Abnormalities of Collagen Collagen makes up >60% of the protein in bone and cartilage, and a large percentage of dry weight of skin, tendons, ligaments Has a very precise structure, and is vulnerable to disruption Examples: Chondrodysplasia: Collagen chains are asymmetric and too wide, causing stunted growth and deformed joints Marfan syndrome: Deficiency of the protein fibrillin; leads to long limbs, spindly fingers, sunken chest, weak aorta, dislocation of the lens of the eye

26 Categories of Connective Tissue Connective tissues can be classified in 2 major categories: Connective Tissue Proper: Loose connective tissues: Areolar Adipose Reticular Dense connective tissues: Dense Regular Dense Irregular Elastic Specialized connective tissues: Cartilage Bone Blood McGraw-Hill Education

27 Figures 5.19 and 5.20 Connective Tissue Types Areolar Connective Tissue: Forms thin, delicate membranes Cells are mainly fibroblasts Gel-like ground substance Collagenous & elastic fibers In subcutaneous layer Beneath most epithelia, where it nourishes nearby epithelial cells Adipose Tissue: Adipocytes store fat Push their nuclei to one side Crowd out other cell types Cushions and insulates Beneath skin (subcutaneous layer) Behind eyeballs Around kidneys and heart Spaces between muscles McGraw-Hill Education Top: b: McGraw-Hill Education/Al Telser, photographer Bottom: b: McGraw-Hill Education/Al Telser, photographer

28 Figures 5.21 and 5.22 Connective Tissue Types Reticular Connective Tissue: Composed of thin reticular fibers Supports walls of internal organs Walls of liver, spleen Dense Regular Connective Tissue: Closely packed collagenous fibers Fine network of elastic fibers Most cells are fibroblasts Very strong, withstands pulling Binds body parts together Tendons, ligaments, dermis Poor blood supply; slow to heal McGraw-Hill Education Top: b: McGraw-Hill Education/Al Telser, photographer Bottom: b: McGraw-Hill Education/Dennis Strete

29 Figures 5.23 and 5.24 Connective Tissue Types Dense Irregular Connective Tissue: Randomly organized, thick, interwoven collagenous fibers Can withstand tension exerted from different directions Dermis of skin Around skeletal muscles Elastic Connective Tissue: Abundant yellow elastic fibers Some collagenous fibers Fibroblasts Attachments between bones of spinal column Walls of hollow organs, such as large arteries, airways Parts of heart Elastic quality, stretches McGraw-Hill Education Top: Victor P. Eroschenko Bottom: McGraw-Hill Education/Al Telser, photographer

30 Cartilage: Connective Tissue Types A rigid, specialized connective tissue Support, framework, attachments Protection of underlying tissue Models for developing bone Matrix contains collagen in gel-like ground substance Chondrocytes (cartilage cells) in lacunae (chambers), surrounded by matrix Lacks blood supply; heals slowly Covered by perichondrium (connective tissue), which provides some nutrients to the cartilage 3 types of cartilage: Hyaline, Elastic, and Fibrocartilage McGraw-Hill Education

31 Figures 5.25 and 5.26 Connective Tissue Types Hyaline cartilage: Most common type Fine collagen fibers Ends of bones in joints Nose, respiratory passages Embryonic skeleton Elastic cartilage: Flexible, due to elastic fibers in matrix External ear, larynx McGraw-Hill Education Top: b: McGraw-Hill Education/Al Telser, photographer Bottom: b: McGraw-Hill Education/Al Telser, photographer

32 Figure 5.27 Connective Tissue Types Fibrocartilage: Very tough, due to many collagenous fibers Shock absorber Intervertebral discs Pads of knee and pelvic girdle McGraw-Hill Education b: Victor P. Eroschenko

33 Connective Tissue Types Bone (Osseous Tissue): Most rigid connective tissue Solid matrix, composed of mineral (Ca) salts & collagen Supports structures Protects vital structures Produces blood cells Stores & releases Ca, P Attachment sites for muscles Forms skeleton Contain osteocytes (bone cells) in lacunae 2 types: compact and spongy McGraw-Hill Education

34 Figure 5.28 Connective Tissue Types Compact Bone: Osteoblasts deposit matrix in lamellae (layers) Lamellae occur in rings around central canals Osteocytes + matrix + central canal form cylindrical units called Osteons: Osteons are cemented together to form compact bone Central canals contain blood vessels; bone is well-nourished, heals more quickly than cartilage McGraw-Hill Education b: McGraw-Hill Education/Sennis Strete, phototgrapher. c: Prof. P. Motta/Univ. La Sapienza /Science Source

35 Figure 5.29 Connective Tissue Types Blood: Cells suspended in fluid matrix called plasma Red blood cells transport gases White blood cells defend again infection Platelets help in blood clotting Transports substances around body McGraw-Hill Education b: McGraw-Hill Education/Dennis Strete, photographer

36 Table 5.7 Connective Tissues Type Description Function Location Areolar connective tissue Cells in fluid-gel matrix Binds organs Beneath the skin, between muscles, beneath epithelial tissues Adipose tissue Cells in fluid-gel matrix Protects, insulates, stores fat Beneath the skin, around the kidneys, behind the eyeballs, on the surface of the heart Reticular connective tissue Dense regular connective tissue Dense irregular connective tissue Elastic connective tissue Cells in fluid-gel matrix Supports Walls of liver and spleen Cells in fluid-gel matrix Binds body parts Tendons, ligaments Cells in fluid-gel matrix Sustains tissue tension In the deep layer of skin Cells in fluid-gel matrix Provides elastic quality Connecting parts of the spinal column, in walls of arteries and airways Hyaline cartilage Cells in solid-gel matrix Supports, protects, provides framework Elastic cartilage Cells in solid-gel matrix Supports, protects, provides flexible framework Fibrocartilage Cells in solid-gel matrix Supports, protects, absorbs shock Bone Cells in solid matrix Supports, protects, provides framework Blood Cells and platelets in fluid matrix Transports gases, defends against disease, clotting Ends of bones, nose, and rings in walls of respiratory passages Framework of external ear and part of larynx Between bony parts of spinal column, parts of pelvic girdle, and knee Bones of skeleton, middle ear Throughout the body in a closed system of blood vessels and heart chambers

37 5-4 Types of Membranes & Muscle/Nervous Tissue (pgs )

38 Types of Membranes (1) Membranes are sheets of cells Epithelial membranes are composed of epithelial and connective tissue; cover body surfaces and line cavities 3 types of epithelial membranes: 1. Serous membranes: Line body cavities that do not open to outside of body Inner linings of thorax and abdomen; covers organs Simple squamous epithelium + areolar connective tissue Secrete serous fluid for lubrication, reducing friction 2. Mucous membranes: Line cavities and tubes that open to the outside of body Lining of digestive, respiratory, urinary, and reproductive tracts Epithelium + areolar connective tissue Goblet cells secrete mucus

39 Types of Membranes (2) 3. Cutaneous membranes: Covers body surface Commonly called skin Part of integumentary system 4. Synovial membranes: Different from epithelial membranes Composed entirely of connective tissue Line joint cavities

40 Figure 5.30 Muscle Tissues General Characteristics: Muscle cells are also called muscle fibers Contractile; can shorten and thicken 3 types of muscle tissue: skeletal, cardiac, and smooth Skeletal muscle tissue: Attached to bones Striated Voluntary Multinucleated cells Long cylindrical cells Stimulated by nerve cells McGraw-Hill Education b: McGraw-Hill Education/Al Telser

41 Figures 5.31 and 5.32 Muscle Tissues Smooth muscle tissue: Non-striated Spindle-shaped fibers Walls of hollow organs Walls of blood vessels Involuntary Cardiac muscle tissue: Only in wall of heart Branching cells Involuntary Striated Intercalated discs McGraw-Hill Education Top: b: McGraw-Hill Education/Al Telser, photographer Bottom: b: McGraw-Hill Education/Al Telser, photographer

42 Figure 5.33 Nervous Tissue Nervous tissues: Found in brain, spinal cord, peripheral nerves Main cells are neurons, which are specialized for communication, via conduction of nerve impulses (sensory reception, motor control) Neurons coordinate, integrate, and regulate body functions Neuroglia support and nourish neurons McGraw-Hill Education b: McGraw-Hill Education/Al Telser, photographer

43 From Science to Technology 5.2 Tissue Engineering: Building a Replacement Bladder Donor organs are in short supply Tissue Engineering is showing promise for organ replacement, by growing cells or extracellular matrix from a person s own cells or matrix, on a synthetic scaffold. No rejection by immune system Has already been used to provide skin, cartilage, bone, blood vessels Urinary bladders are being replaced by growing tissue donated by the patient Patient s bladder tissue contains progenitor cells for smooth muscle and uroepithelium, which are used to grow a new bladder on a synthetic dome After implant, synthetic scaffold degenerates over time, leaving new bladder in place

44 Table 5.8 Muscle and Nervous Tissues Type Description Function Location Skeletal muscle tissue Smooth muscle tissue Cardiac muscle tissue Nervous tissue Long, thread-like cells, striated, many nuclei Shorter cells, single, central nucleus Branched cells, striated, single nucleus Cells with cytoplasmic extensions Voluntary movements of skeletal parts Involuntary movements of internal organs Heart movements Sensory reception, release of neurotransmitter, and conduction of electrical impulses Muscles usually attached to bones Walls of hollow internal organs Heart muscle Brain, spinal cord, and peripheral nerves