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- 1. Anatomy and Physiology Dr. Ali Jibbawi 30 June 2023 1 UNIT:3 TISSUES Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
- 2. Introduction 2 • Similar cells with a common function are called tissues. • The study of the shape and arrangement of cells in tissues is called histology. •All cells and tissues in the body derive from three germ layers in the embryo: the ectoderm, mesoderm, and endoderm. •There are four (4) primary or major tissue types: 1. Epithelial Tissue 2. Connective Tissue 3. Muscle Tissue 4. Nervous Tissue
- 3. Intercellular Junctions 3 Tight junctions • Close space between cells • Located among cells that form linings Desmosomes • Form “spot welds” between cells • Located among outer skin cells Gap junctions • Tubular channels between cells • Located in cardiac muscle cells Tight junction Cell membrane Cell membrane Cell membrane Desmosome Gap junction Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
- 4. 5.2: Epithelial Tissue 4 • General characteristics: o Cover organs and the body o Line body cavities o Line hollow organs o Have a free surface o Have a basement membrane o Are avascular o Cells readily divide o Cells tightly packed o Cells often have desmosomes o Function in protection, secretion, absorption, and excretion o Classified according to cell shape and number of cell layers
- 5. Epithelial Tissue 5 • Simple squamous: • Single layer of flat cells • Substances pass easily through • Line air sacs • Line blood vessels • Line lymphatic vessels • Simple cuboidal: • Single layer of cube-shaped cells • Line kidney tubules • Cover ovaries • Line ducts of some glands (b) (a) Free surface of tissue Simple squamous epithelium Basement Nucleus Connective tissue Connective tissue Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. b,d: © Ed Reschke Nucleus Basement membrane Free surface of tissue Simple cuboidal epithelium Connective tissue Lumen (a) (b) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. b: © The McGraw-Hill Companies, Inc./Al Telser, photographer
- 6. Epithelial Tissue 6 • Simple columnar: • Single layer of elongated cells • Nuclei usually near the basement • Membrane at same level • Sometimes possess cilia • Sometimes possess microvilli • Often have goblet cells • Line uterus, stomach, intestines • Pseudostratified columnar: • Single layer of elongated cells • Nuclei at two or more levels • Appear striated • Often have cilia • Often have goblet cells • Line respiratory passageways Nucleus Basement membrane Microvilli (free surface of tissue) Connective tissue Mucus Cytoplasm Goblet cell (a) (b) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. b: © The McGraw-Hill Companies, Inc./Al Telser, photographer. (a) (b) Cilia (free surface of tissue) Goblet cell Basement membrane Nucleus Connective tissue Cytoplasm Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. b: © The McGraw-Hill Companies, Inc./Dennis Strete, photographer
- 7. Epithelial Tissue 7 • Stratified squamous: • Many cell layers • Top cells are flat • Can accumulate keratin • Outer layer of skin • Line oral cavity, vagina, and anal canal • Stratified cuboidal: • 2-3 layers • Cube-shaped cells • Line ducts of mammary glands, sweat glands, salivary glands, and the pancreas Basement membrane Layer of dividing cells Connective tissue Free surface of tissue Squamous cells (b) (a) Copyright © The McGraw-HillCompanies, Inc. Permission required for reproduction or display. b: © The McGraw-Hill Companies, Inc./Al Telser, photographer (a) (b) Stratified cuboidal epithelium Free surface of tissue Lumen Basement membrane Connective tissue Nucleus Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. b: © The McGraw-Hill Companies, Inc./Al Telser, photographer.
- 8. Epithelial Tissue 8 • Stratified columnar: • Top layer of elongated cells • Cube-shaped cells in deeper layers • Line part of male urethra and part of pharynx • Transitional: • Many cell layers • Cube-shaped and elongated cells • Line urinary bladder, ureters, and part of urethra (b) (a) Lumen Stratified columnar epithelium Connective tissue Basement membrane Free surface of tissue Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. b: © The McGraw-Hill Companies, Inc./Al Telser, photographer Stretched transitional epithelium Basement membrane Underlying connective tissue Basement membrane Underlying connective tissue Unstretched transitional epithelium (b) (a) (d) (c) Free surface of tissue Free surface of tissue Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. b,d: © Ed Reschke
- 9. Glandular Epithelium 9 • Composed of cells that are specialized to produce and secrete substances • There are two (2) types: • Endocrine glands are ductless (key word: hormone) • Exocrine glands have ducts •Unicellular exocrine gland: • Composed of one cell • Goblet cell • Multicellular exocrine gland: • Composed of many cells • Sweat glands, salivary glands, etc. • Simple and compound
- 10. Structural Types of Exocrine Glands 10 Duct Secretory portion Tissue surface Simple tubular Simple branched tubular Simple branched alveolar Simple coiled tubular Compound tubular Compound alveolar Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
- 11. Types of Glandular Secretions 11 • Merocrine Glands • Fluid product • Salivary glands • Pancreas gland (?) • Sweat glands • Apocrine Glands • Cellular product • Portions of cells • Mammary glands • Ceruminous glands • Holocrine Glands • Secretory products • Whole cells • Sebaceous glands (a) Merocrine gland (b) Apocrine gland (c) Holocrine gland Secretion Pinched off portion of cell (secretion) Intact cell Disintegrating cell and its contents (secretion) New cell forming by mitosis and cytokinesis Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
- 12. Connective Tissues 12 • General characteristics: • Most abundant tissue type •Have a matrix • Have varying degrees of vascularity •Have cells that usually divide •Many functions: • Bind structures • Provide support and protection • Serve as frameworks • Fill spaces • Store fat • Produce blood cells • Protect against infections • Help repair tissue damage
- 13. Connective Tissue Major Cell Types Present 13 • Fibroblasts • Fixed cell • Most common cell • Large, star-shaped • Produce fibers • Macrophages • Wandering cell • Phagocytic • Important in injury or infection • Mast cells • Fixed cell • Release heparin • Release histamine
- 14. Connective Tissue Fiber Types Present 14 • Collagenous fibers • Thick • Composed of collagen • Great tensile strength • Abundant in dense CT • Hold structures together • Tendons, ligaments • Elastic fibers • Bundles of microfibrils embedded in elastin • Fibers branch • Elastic • Vocal cords, air passages • Reticular fibers • Very thin collagenous fibers • Highly branched • Form supportive networks
- 15. Connective Tissues 15 • Connective Tissue Proper: • Loose connective tissue • Adipose tissue • Reticular connective tissue • Dense connective tissue • Elastic connective tissue • Specialized Connective Tissue: • Cartilage • Bone • Blood
- 16. Connective Tissue Types 16 • Loose Connective Tissue • Mainly fibroblasts • Fluid to gel-like matrix • Collagenous fibers • Elastic fibers • Bind skin to structures • Beneath most epithelia • Blood vessels nourish nearby epithelial cells • Between muscles Elastic fiber (a) (b) Collagenous fiber Fibroblast Ground substance Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. b: © The McGraw-Hill Companies, Inc./Dennis Strete, photographer (a)
- 17. Connective Tissue Types 17 • Adipose Tissue • Adipocytes • Cushions • Insulates • Store fats • Beneath skin • Behind eyeballs • Around kidneys and heart (a) b: © The McGraw-Hill Companies, Inc./Dennis Strete, photographer Fat droplet (a) (b) Nucleus Cell membrane Cytsol Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. b: © The McGraw-Hill Companies, Inc./Dennis Strete, photographer
- 18. Connective Tissue Types 18 • Reticular Connective Tissue • Composed of reticular fibers • Supports internal organ walls • Walls of liver, spleen, lymphatic organs Collagenous fibers Fibroblast White blood cell (a) (b) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. b: © The McGraw-Hill Companies, Inc./Al Telser, photographer (a)
- 19. Connective Tissue Types 19 • Dense Connective Tissue • Packed collagenous fibers • Elastic fibers • Few fibroblasts • Bind body parts together • Tendons, ligaments, dermis • Poor blood supply (a) Fibroblasts Collagenous fibers (a) (b) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. b: © The McGraw-Hill Companies, Inc./Dennis Strete, photographer
- 20. Connective Tissue Types • Elastic Connective Tissue • Abundant in elastic fibers • Some collagenous fibers • Fibroblasts • Attachments between bones • Walls of large arteries, airways, heart Elastic fibers Collagenous fibers Fibroblast (a) (b) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. b: © The McGraw-Hill Companies, Inc./Al Telser, photographer (a)
- 21. Connective Tissue Types • Bone (Osseous Tissue) • Solid matrix • Supports • Protects • Forms blood cells • Attachment for muscles • Skeleton • Osteocytes in lacunae (a) Canaliculi Osteocyte in lacuna Central canal Lamella Nucleus Osteocyte Cell process in canaliculus (a) (b) Osteon Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display b: © The McGraw-Hill Companies, Inc./Dennis Strete, photographer
- 22. Connective Tissue Types 22 • Cartilage • Rigid matrix • Chondrocytes in lacunae • Poor blood supply • Three (3) types: • Hyaline Cartilage • Elastic Cartilage • Fibrocartilage • Hyaline cartilage • Most abundant • Ends of bones • Nose, respiratory passages • Embryonic skeleton • Elastic cartilage • Flexible • External ear, larynx • Fibrocartilage • Very tough • Shock absorber • Intervertebral discs • Pads of knee and pelvic girdle
- 23. Connective Tissue Types 23 Three (3) types of cartilage: Hyaline Cartilage Elastic Cartilage Fibrocartilage Chondrocyte Nucleus Extracellular matrix (a) (b) Lacuna Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chondrocyte Elastic fibers Nucleus Extracellular matrix (a) (b) Lacuna Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chondrocyte Nucleus Collagenous fiber Extracellular matrix (a) (b) Lacuna Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. b: © The McGraw-Hill Companies, Inc./Al Telser, photographer
- 24. Connective Tissue Types 24 • Blood • Fluid matrix called plasma • Red blood cells • White blood cells • Platelets • Transports • Defends • Involved in clotting • Throughout body in blood vessels • Heart Red blood cells Plasma (extracellular matrix of blood) Platelets White blood cell (a) (b) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. b: © The McGraw-Hill Companies, Inc./Al Telser, photographer
- 25. Types of Membranes 25 Serous Membranes • Line body cavities that do not open to the outside • Reduce friction • Inner lining of thorax and abdomen • Cover organs of thorax and abdomen • Secrete serous fluid Mucous Membranes • Line tubes and organs that open to outside world • Lining of mouth, nose, throat, etc. • Secrete mucus • There are four (4) types of epithelial membranes:
- 26. Types of Membranes 26 Cutaneous Membranes • Covers body • Skin Synovial Membranes • Composed entirely of connective tissue • Lines joints • There are four (4) types of epithelial membranes:
- 27. Muscle Tissues 27 • General characteristics: • Muscle cells also called muscle fibers • Contractile • Three (3) types: • Skeletal muscle • Smooth muscle • Cardiac muscle • Skeletal muscle • Attached to bones • Striated • Voluntary • Smooth muscle • Walls of organs • Skin • Walls of blood vessels • Involuntary • Non-striated • Cardiac muscle • Heart wall • Involuntary • Striated • Intercalated discs
- 28. Muscle Tissue 28 Skeletal Muscle Smooth Muscle Cardiac Muscle Striations Portion of a muscle fiber Nuclei (a) (b) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. b: © The McGraw-Hill Companies, Inc./Al Telser, photographer Nucleus Cytoplasm (a) (b) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. b: © The McGraw-Hill Companies, Inc./Dennis Strete, photographer Intercalated disc Nucleus Striations (a) (b) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. b: © The McGraw-Hill Companies, Inc./Al Telser, photographer
- 29. Nervous Tissue 29 • Found in brain, spinal cord, and peripheral nerves • Functional cells are neurons • Neuroglial cells support and • bind nervous tissue components • Sensory reception • Conduction of nerve impulses Cell membrane Neuroglial cells Cytoplasm Cellular process Nucleus (a) (b) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. b: © Ed Reschke.
- 30. Tissue Injury and Repair •Inflammation is the standard, initial response of the body to injury. Whether biological, chemical, physical, or radiation • Apoptosis is programmed cell death, a normal step-by-step process that destroys cells no longer needed by the body. •Acute inflammation resolves over time by the healing of tissue. If inflammation persists, it becomes chronic and leads to diseased conditions. Arthritis and tuberculosis are examples of chronic inflammation. • The four cardinal signs of inflammation—redness, swelling, pain, and local heat—were first recorded in antiquity. loss of function, may also accompany inflammation. 30
- 31. Tissue Injury and Repair During wound repair, collagen fibers are laid down randomly by fibroblasts that move into repair the area. 31
- 32. Conclusion •The human body contains more than 200 types of cells that can all be classified into four types of tissues: epithelial, connective, muscle, and nervous. •Epithelial tissues act as coverings controlling the movement of materials across the surface. •Connective tissue integrates the various parts of the body and provides support and protection to organs. •Muscle tissue allows the body to move. •Nervous tissues propagate information. 32
Editor's Notes
- Upon tissue injury, damaged cells release inflammatory chemical signals that evoke local vasodilation, the widening of the blood vessels. Increased blood flow results in apparent redness and heat. In response to injury, mast cells present in tissue degranulate, releasing the potent vasodilator histamine. Increased blood flow and inflammatory mediators recruit white blood cells to the site of inflammation. The endothelium lining the local blood vessel becomes “leaky” under the influence of histamine and other inflammatory mediators allowing neutrophils, macrophages, and fluid to move from the blood into the interstitial tissue spaces. The excess liquid in tissue causes swelling, more properly called edema. The swollen tissues squeezing pain receptors cause the sensation of pain. Prostaglandins released from injured cells also activate pain neurons. Non-steroidal anti-inflammatory drugs (NSAIDs) reduce pain because they inhibit the synthesis of prostaglandins. High levels of NSAIDs reduce inflammation. Antihistamines decrease allergies by blocking histamine receptors and as a result the histamine response. After containment of an injury, the tissue repair phase starts with removal of toxins and waste products. Clotting (coagulation) reduces blood loss from damaged blood vessels and forms a network of fibrin proteins that trap blood cells and bind the edges of the wound together. A scab forms when the clot dries, reducing the risk of infection. Sometimes a mixture of dead leukocytes and fluid called pus accumulates in the wound. As healing progresses, fibroblasts from the surrounding connective tissues replace the collagen and extracellular material lost by the injury. Angiogenesis, the growth of new blood vessels, results in vascularization of the new tissue known as granulation tissue. The clot retracts pulling the edges of the wound together, and it slowly dissolves as the tissue is repaired. When a large amount of granulation tissue forms and capillaries disappear, a pale scar is often visible in the healed area. A primary union describes the healing of a wound where the edges are close together. When there is a gaping wound, it takes longer to refill the area with cells and collagen. The process called secondary union occurs as the edges of the wound are pulled together by what is called wound contraction. When a wound is more than one quarter of an inch deep, sutures (stitches) are recommended to promote a primary union and avoid the formation of a disfiguring scar. Regeneration is the addition of new cells of the same type as the ones that were injured (Figure 4.21).
- Upon tissue injury, damaged cells release inflammatory chemical signals that evoke local vasodilation, the widening of the blood vessels. Increased blood flow results in apparent redness and heat. In response to injury, mast cells present in tissue degranulate, releasing the potent vasodilator histamine. Increased blood flow and inflammatory mediators recruit white blood cells to the site of inflammation. The endothelium lining the local blood vessel becomes “leaky” under the influence of histamine and other inflammatory mediators allowing neutrophils, macrophages, and fluid to move from the blood into the interstitial tissue spaces. The excess liquid in tissue causes swelling, more properly called edema. The swollen tissues squeezing pain receptors cause the sensation of pain. Prostaglandins released from injured cells also activate pain neurons. Non-steroidal anti-inflammatory drugs (NSAIDs) reduce pain because they inhibit the synthesis of prostaglandins. High levels of NSAIDs reduce inflammation. Antihistamines decrease allergies by blocking histamine receptors and as a result the histamine response. After containment of an injury, the tissue repair phase starts with removal of toxins and waste products. Clotting (coagulation) reduces blood loss from damaged blood vessels and forms a network of fibrin proteins that trap blood cells and bind the edges of the wound together. A scab forms when the clot dries, reducing the risk of infection. Sometimes a mixture of dead leukocytes and fluid called pus accumulates in the wound. As healing progresses, fibroblasts from the surrounding connective tissues replace the collagen and extracellular material lost by the injury. Angiogenesis, the growth of new blood vessels, results in vascularization of the new tissue known as granulation tissue. The clot retracts pulling the edges of the wound together, and it slowly dissolves as the tissue is repaired. When a large amount of granulation tissue forms and capillaries disappear, a pale scar is often visible in the healed area. A primary union describes the healing of a wound where the edges are close together. When there is a gaping wound, it takes longer to refill the area with cells and collagen. The process called secondary union occurs as the edges of the wound are pulled together by what is called wound contraction. When a wound is more than one quarter of an inch deep, sutures (stitches) are recommended to promote a primary union and avoid the formation of a disfiguring scar. Regeneration is the addition of new cells of the same type as the ones that were injured (Figure 4.21).
- Upon tissue injury, damaged cells release inflammatory chemical signals that evoke local vasodilation, the widening of the blood vessels. Increased blood flow results in apparent redness and heat. In response to injury, mast cells present in tissue degranulate, releasing the potent vasodilator histamine. Increased blood flow and inflammatory mediators recruit white blood cells to the site of inflammation. The endothelium lining the local blood vessel becomes “leaky” under the influence of histamine and other inflammatory mediators allowing neutrophils, macrophages, and fluid to move from the blood into the interstitial tissue spaces. The excess liquid in tissue causes swelling, more properly called edema. The swollen tissues squeezing pain receptors cause the sensation of pain. Prostaglandins released from injured cells also activate pain neurons. Non-steroidal anti-inflammatory drugs (NSAIDs) reduce pain because they inhibit the synthesis of prostaglandins. High levels of NSAIDs reduce inflammation. Antihistamines decrease allergies by blocking histamine receptors and as a result the histamine response. After containment of an injury, the tissue repair phase starts with removal of toxins and waste products. Clotting (coagulation) reduces blood loss from damaged blood vessels and forms a network of fibrin proteins that trap blood cells and bind the edges of the wound together. A scab forms when the clot dries, reducing the risk of infection. Sometimes a mixture of dead leukocytes and fluid called pus accumulates in the wound. As healing progresses, fibroblasts from the surrounding connective tissues replace the collagen and extracellular material lost by the injury. Angiogenesis, the growth of new blood vessels, results in vascularization of the new tissue known as granulation tissue. The clot retracts pulling the edges of the wound together, and it slowly dissolves as the tissue is repaired. When a large amount of granulation tissue forms and capillaries disappear, a pale scar is often visible in the healed area. A primary union describes the healing of a wound where the edges are close together. When there is a gaping wound, it takes longer to refill the area with cells and collagen. The process called secondary union occurs as the edges of the wound are pulled together by what is called wound contraction. When a wound is more than one quarter of an inch deep, sutures (stitches) are recommended to promote a primary union and avoid the formation of a disfiguring scar. Regeneration is the addition of new cells of the same type as the ones that were injured (Figure 4.21).