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Chapter 5 - histology

Chapter 5 - histology. Tissues. Tissue is composed of similar cells to perform a particular function. Cells are surrounded by non-living material called the matrix. The density of the matrix determines the rigidity of the tissue. T ypes of tissues.

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Chapter 5 - histology

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  1. Chapter 5 - histology Tissues

  2. Tissue is composed of similar cells to perform a particular function

  3. Cells are surrounded by non-living material called the matrix

  4. The density of the matrix determines the rigidity of the tissue

  5. Types of tissues • Epithelial – surface, lining body cavities • Connective – hard and soft • Muscle – movement • Nervous - communication

  6. Embryonic development • After two wks. three germ layers produced – endoderm, mesoderm, ectoderm • Histogenesis determines the tissue type. • Epitheial – all • Connective/muscle – mesoderm • Nervous - ectoderm

  7. Epithelial Tissue – two categories • Membranous – • Body covering • Vessels • Resp., digestive, GU systems • Glandular - • Endocrine and exocrine glands

  8. Epithelial functions • Protection • Sensory – skin, nose, eye, ear • Secretion – hormones, sweat, mucus, digestive enzymes • Absorption – gut – resp. gases • Excretion – renal tubules

  9. Epithelial generalizations • Limited matrix material • Under scope appears as tightly packed sheets • Epithelium attached to basal membrane (layer of connective tissue by a thin noncellular layer) • Glycoproteins (basal lamina) secreted by epithelial cells and a mesh of fibers (reticular lamina) produced by the connective tissue • Adhesive molecules (integrins) help bind cytoskeleton of epithelial cells to basement membrane

  10. Avascular • Diffusion allows for O2 and nutrients • Can reproduce themselves

  11. classification • Based on cell shape • Based on layers of cells

  12. Simple squamous • Give criteria • Flat • One layer • Scale-like • Diffusion easy through this tissue • Alveoli, pleura, pericardium, lymph vessels

  13. Shape - squamous

  14. Simple cuboidal • One layer • Cube shaped • Glands • kidneys

  15. Shape - cuboidal

  16. Simple columnar • Mucus membrane • Stomach lining • Uterus • Intestine • Goblet cells – secretory vesicles – mucus • Microvilli present • Surface structure expands – fan demo

  17. Shape - columnar

  18. Peudostratified columnar • Air passages • Urethra • Cells differ in height and gives false impression of stratification • Resp.system lining = cilia moves one direction for protection = in or out?

  19. Shape - pseudostratified

  20. Layers – simple – one cell thickness

  21. Stratified epithelium – more that one cell thickness

  22. Stratified squamous • Keratinized • Protective factor on outer surface -keratohyaline • Resistance to friction and traction • Dry • Typically impermeable • Non-keratinized • Lining the vagina, mouth, esophagus • Free surface is moist • Allows diffusion of materials

  23. Stratified cuboidal • Two or more rows arranged randomly over basement membrane • Sweat gland ducts • Pharynx • Part of epiglottis

  24. Stratified columnar • Multiple layers • Rare locations • Male urethra • Mucus layer near anus

  25. Stratified transition • Find in areas of stress and tension change • Wall of bladder • Shape changes from cuboidal to columnar • DURING THE VOIDING PROCESSS, THIS TISSUE GOES THROUGH GREAT TRANSITION!

  26. Lego lab

  27. Glandular • Secretory in nature • Exocrine glands – discharge secretion into ducts • saliva • Endocrine glands – discharge secretion into the blood • hormones

  28. Classification of exocrine glands • Apocrine • Holocrine • Merocrine

  29. Apocrine - mammary

  30. Holocrine - sebaceous

  31. Merocrine - salivary

  32. Points to Ponder………. ? • What is the most widespread abundant tissue? • Nerve tissue is derived from what germ layer? • Define tissue • Blood is a member of what tissue type?

  33. Ponder…. • What tissue lines body cavities? • Function of epithelial tissue • Where is keratinized squamous epithelium found? • Know glandular differences • Function of connective tissue • Where is collagenous tissue found?

  34. One of the Most widespread tissues in the body Connective Tissue

  35. Varied forms • Delicate tissue paper webs • Tough resilient cords • Rigid bones • Blood

  36. functions • Connects – muscle to muscle • Supports - framework • Transports - nutrients, hormones, waste • Defends - skin

  37. characteristics • Matrix – intracellular material • Ground substance – embedded in matrix along with fibers and fluid • Qualities of matrix and fibers determine structure of tissue • Blood – matrix is plasma – no fibers, many cells (except during coagulation) • Number of fibers determine consistency/strength

  38. Connective tissue matrix:one or more fibers • Collagenous – white – tough and strong – occur in bundles (provides strength) • Possibly accounting for more than one-fourth of protein in body • Typically reflects aging process • Reticular – elastic and delicate – occur in networks (supports nerves, capillaries) • These are produced by fibroblasts and some other cells

  39. Elastic fibers • Made of elastin • Found in tissues that can stretch – nose, etc. • What do you know about elastic products?

  40. Barriers and glue • Protein fibers + proteoglycans (polysacharide chains – glucosamine) = matrix fluid • This fluid is thick • Barrier for microbes • Also, transparent lubricant to hold tissue together

  41. classification • Structural characteristics of the intracellular material • Fibrous – extracellular fibers are predominant feature • Bone – fibers and hard mineral ground substance • Cartilage – ground substance traps water to form a firm gel • Blood - lack of fibers in matrix

  42. fibrous • Loose/ordinary/areolar • Stretchable • Most widely distributed of all tissues • Connects adjacent structures – acts like glue that permits movement • Term areolar refers to bubbly effect when pulled apart on dissection • Matrix is soft, thick gel but hyaluronic acid can turn it watery • IM absorption increases with watery state • Strep bacterium release this acid to allow for ease of permeability

  43. Macrophages carry on phagocytosis • Type of WBC – mast cell

  44. adipose • Predominately fat cells and few fibroblasts, macrophages and mast cells • Provides padding • Storage • insulation

  45. reticular • Three dimensional web (reticular network) • Framework of the spleen, lymph, bone marrow • Defense mechanism that acts as a filter, traps and eats invaders

  46. Dense fibrous tissue • Fibers packed densely in matrix • Few fibroblasts • Regular/irregular – depends on arrangement of fibers • Dense – bundles of fibers of collagen – tendons (flexible and great strength) • ligament – mostly elastic fibers • Irregular – bundles not in parallel rows, but thick mat - dermis

  47. bone • Osseous • Most specialized of connective tissue • Collagen and mineral salts (65%) which creates density and strength • Support/protection/mineral reserve • Basic unit of the bone is the osteon (Haversian system) • Osteocytes located in lacunae – arranged in concentric manner called lamellae • Canaliculi connect each lacuna and osteocyte with bl vessels in Haversian canal

  48. Osteoblast • Osteocyte • osteoclast

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