PowerPoint ® Lecture Slides prepared by Barbara Heard, Atlantic Cape Community College C H A P T E R © 2013 Pearson Education, Inc.© Annie Leibovitz/Contact Press Images Tissue: The Living Fabric: Part B 4

© 2013 Pearson Education, Inc. Muscle Tissue Highly vascularized Responsible for most types of movement Three types –Skeletal muscle tissue Found in skeletal muscle Voluntary –Cardiac muscle tissue Found in walls of heart Involuntary –Smooth muscle tissue Mainly in walls of hollow organs other than heart Involuntary

© 2013 Pearson Education, Inc. Skeletal muscle Description: Long, cylindrical, multinucleate cells; obvious striations. Function: Voluntary movement; locomotion; manipulation of the environment; facial expression; voluntary control. Location: In skeletal muscles attached to bones or occasionally to skin. Photomicrograph: Skeletal muscle (approx. 440x). Notice the obvious banding pattern and the fact that these large cells are multinucleate. Striations Nuclei Part of muscle fiber (cell) Figure 4.9a Muscle tissues.

© 2013 Pearson Education, Inc. Cardiac muscle Description: Branching, striated, generally uninucleate cells that interdigitate at specialized junctions (intercalated discs). Function: As it contracts, it propels blood into the circulation; involuntary control. Location: The walls of the heart. Photomicrograph: Cardiac muscle (900x); notice the striations, branching of cells, and the intercalated discs. Striations Nucleus Intercalated discs Figure 4.9b Muscle tissues.

© 2013 Pearson Education, Inc. Smooth muscle Description: Spindle-shaped cells with central nuclei; no striations; cells arranged closely to form sheets. Function: Propels substances or objects (foodstuffs, urine, a baby) along internal passageways; involuntary control. Location: Mostly in the walls of hollow organs. Photomicrograph: Sheet of smooth muscle (720x). Smooth muscle cell Nuclei Figure 4.9c Muscle tissues.

© 2013 Pearson Education, Inc. Nervous Tissue Main component of nervous system –Brain, spinal cord, nerves –Regulates and controls body functions Neurons –Specialized nerve cells that generate and conduct nerve impulses Neuroglia –Supporting cells that support, insulate, and protect neurons

© 2013 Pearson Education, Inc. Nervous tissue Description: Neurons are branching cells; cell processes that may be quite long extend from the nucleus-containing cell body; also contributing to nervous tissue are nonexcitable supporting cells. Function: Neurons transmit electrical signals from sensory receptors and to effectors (muscles and glands) which control their activity; supporting cells support and protect neurons. Location: Brain, spinal cord, and nerves. Photomicrograph: Neurons (350x). Neuron processes Nuclei of supporting cells Cell body of a neuron Neuron processesCell body Axon Dendrites Figure 4.10 Nervous tissues.

© 2013 Pearson Education, Inc. Covering and Lining Membranes Composed of at least two primary tissue types –An epithelium bound to underlying connective tissue proper –Are simple organs Three types –Cutaneous membranes –Mucous membranes –Serous membranes

© 2013 Pearson Education, Inc. Cutaneous Membranes Skin Keratinized stratified squamous epithelium (epidermis) attached to a thick layer of connective tissue (dermis) Dry membrane

© 2013 Pearson Education, Inc. Cutaneous membrane The cutaneous membrane (the skin) covers the body surface. Cutaneous membrane (skin) Figure 4.11a Classes of membranes.

© 2013 Pearson Education, Inc. Mucous Membranes Mucosa indicates location not cell composition All called mucosae –Line body cavities open to the exterior (e.g., Digestive, respiratory, urogenital tracts) Moist membranes bathed by secretions (or urine) Epithelial sheet lies over layer of connective tissue called lamina propria May secrete mucus

© 2013 Pearson Education, Inc. Mucous membranes Mucous membranes line body cavities that are open to the exterior. Mucosa of nasal cavity Mucosa of mouth Esophagus lining Mucosa of lung bronchi Figure 4.11b Classes of membranes.

© 2013 Pearson Education, Inc. Serous Membranes Serosae—found in closed ventral body cavity Simple squamous epithelium (mesothelium) resting on thin areolar connective tissue Parietal serosae line internal body cavity walls Visceral serosae cover internal organs Serous fluid between layers Moist membranes Pleurae, pericardium, peritoneum

© 2013 Pearson Education, Inc. Visceral peritoneum Parietal peritoneum Parietal pericardium Visceral pericardium Visceral pleura Parietal pleura Serous membranes line body cavities that are closed to the exterior. Serous membranes Figure 4.11c Classes of membranes.

© 2013 Pearson Education, Inc. Tissue Repair Necessary when barriers are penetrated Cells must divide and migrate Occurs in two major ways –Regeneration Same kind of tissue replaces destroyed tissue Original function restored –Fibrosis Connective tissue replaces destroyed tissue Original function lost

© 2013 Pearson Education, Inc. Steps in Tissue Repair: Step 1 Inflammation sets stage –Release of inflammatory chemicals –Dilation of blood vessels –Increase in vessel permeability –Clotting occurs

© 2013 Pearson Education, Inc. Figure Tissue repair of a nonextensive skin wound: regeneration and fibrosis. Slide 1 Scab Blood clot in incised wound Epidermis Vein Inflammatory chemicals Migrating white blood cell Artery Inflammation sets the stage: Severed blood vessels bleed. Inflammatory chemicals are released. Local blood vessels become more permeable, allowing white blood cells, fluid, clotting proteins, and other plasma proteins to seep into the injured area. Clotting occurs; surface dries and forms a scab. 1

© 2013 Pearson Education, Inc. Steps in Tissue Repair: Step 2 Organization restores blood supply –The blood clot is replaced with granulation tissue –Epithelium begins to regenerate –Fibroblasts produce collagen fibers to bridge the gap –Debris is phagocytized

© 2013 Pearson Education, Inc. Slide 2 Figure Tissue repair of a nonextensive skin wound: regeneration and fibrosis. Regenerating epithelium Area of granulation tissue ingrowth Macrophage Budding capillary Fibroblast Organization restores the blood supply: The clot is replaced by granulation tissue, which restores the vascular supply. Fibroblasts produce collagen fibers that bridge the gap. Macrophages phagocytize dead and dying cells and other debris. Surface epithelial cells multiply and migrate over the granulation tissue. 2

© 2013 Pearson Education, Inc. Steps in Tissue Repair: Step 3 Regeneration and fibrosis –The scab detaches –Fibrous tissue matures; epithelium thickens and begins to resemble adjacent tissue –Results in a fully regenerated epithelium with underlying scar tissue

© 2013 Pearson Education, Inc. Slide 3 Figure Tissue repair of a nonextensive skin wound: regeneration and fibrosis. Regenerated epithelium Fibrosed area Regeneration and fibrosis effect permanent repair: The fibrosed area matures and contracts; the epithelium thickens. A fully regenerated epithelium with an underlying area of scar tissue results. 3

© 2013 Pearson Education, Inc. Regenerative Capacity in Different Tissues Regenerate extremely well –Epithelial tissues, bone, areolar connective tissue, dense irregular connective tissue, blood-forming tissue Moderate regenerating capacity –Smooth muscle and dense regular connective tissue Virtually no functional regenerative capacity –Cardiac muscle and nervous tissue of brain and spinal cord –New research shows cell division does occur Efforts underway to coax them to regenerate better

© 2013 Pearson Education, Inc. Developmental Aspects Primary germ layers –Superficial to deep: ectoderm, mesoderm, and endoderm –Formed early in embryonic development –Specialize to form the four primary tissues Nerve tissue arises from ectoderm Muscle and connective tissues arise from mesoderm Epithelial tissues arise from all three germ layers

© 2013 Pearson Education, Inc. Figure 4.13 Embryonic germ layers and the primary tissue types they produce. 16-day-old embryo (dorsal surface view) Epithelium (from all three germ layers) Ectoderm Mesoderm Endoderm Inner lining of digestive system (from endoderm) Nervous tissue (from ectoderm) Muscle and connec- tive tissue (mostly from mesoderm)

© 2013 Pearson Education, Inc. Aging Tissues Normally function well through youth and middle age if adequate diet, circulation, and infrequent wounds and infections Epithelia thin with increasing age so more easily breached Tissue repair less efficient Bone, muscle and nervous tissues begin to atrophy DNA mutations possible  increased cancer risk