Introduction and Tissues

1. Introduction and Tissues Human AnatomyBIOL 1010 Liston Campus

2. What is Anatomy? • Anatomy (= morphology): study of body’s structure • Physiology: study of body’s function • Structure reflects Function!!! • Branches of Anatomy • Gross: Large structures • Surface: Landmarks • Histology: Cells and Tissues • Developmental: Structures change through life • Embryology: Structures form and develop before birth

3. Hierarchy of Structural Organization Each of these build upon one another to make up the next level: • Chemical level • Cellular • Tissue • Organ • Organ system • Organism

4. Hierarchy of Structural Organization • Chemical level • Atoms combine to make molecules • 4 macromolecules in the body • Carbohydrates • Lipids • Proteins • Nucleic acids

5. Hierarchy of Structural Organization • Cellular • Made up of cells and cellular organelles (molecules) • Cells can be eukaryotic or prokaryotic • Organelles are structures within cells that perform dedicated functions (“small organs” http://cmweb.pvschools.net/~bbecke/newell/Cells.html

6. Hierarchy of Structural Organization • Tissue • Collection of cells that work together to perform a specialized function • 4 basic types of tissue in the human body: • Epithelium • Connective tissue • Muscle tissue • Nervous tissue www.emc.maricopa.edu

7. Hierarchy of Structural Organization • Organ • Made up of tissue • Heart • Brain • Liver • Pancreas, etc…… Pg 158

8. Hierarchy of Structural Organization • Organ system (11) • Made up of a group of related organs that work together • Integumentary • Skeletal • Muscular • Nervous • Endocrine • Cardiovascular • Lymphatic • Respiratory • Digestive • Urinary • Reproductive Circulatory Pg 314

9. Hierarchy of Structural Organization • Organism • An individual human, animal, plant, etc…… • Made up all of the organ systems • Work together to sustain life

10. Anatomical Directions • Anatomical position • Regions • Axial vs. Appendicular • Anatomical Directions-It’s all Relative! • Anterior (ventral) vs. Posterior (dorsal) • Medial vs. Lateral • Superior (cranial) vs. Inferior (caudal) • Superficial vs. Deep • Proximal vs. Distal • Anatomical Planes • Frontal = Coronal • Transverse = Horizontal = Cross Section • Sagittal Pg 3

11. Reference Point

12. Embryology: growth and development of the body before birth • 38 weeks from conception to birth • Prenatal period • Embryonic: weeks 1-8 • Fetal: weeks 9-38 • Basic adult body plan shows by 2nd month • Skin = epidermis, dermis • Outer body wall=muscle, vertebral column and spinal cord • Body cavity and digestive tubes • Kidney and gonads • Limbs=skin, muscle, bone

13. Weeks 5-8 and Fetal Period • Second month, tadpole  person • Tail disappears • Head enlarges • Extremities form (day 28, limb buds appear) • Eyes, nose, ears form • Organs in place • Fetal Period • Rapid growth and maturation • Organs grow and increase in complexity & competence

14. 4 Types of Tissue • Epithelium • Connective • Muscle • Nervous

15. Tissues: groups of cells closely associated that have a similar structure and perform a related function • Four types of tissue • Epithelial = covering/lining • Connective = support • Muscle = movement • Nervous = control • Most organs contain all 4 types • Tissue has non-living extracellular material between its cells

16. EPITHELIAL TISSUE: sheets of cells cover a surface or line a cavity • Functions • Protection • Secretion • Slippery Surface • Absorption • Ion Transport

17. Characteristics of Epithelium • Cellularity • Composed of cells • Specialized Contacts • Joined by cell junctions • Polarity • Apical vs. Basal surfaces differ • Supported by Connective Tissue • Avascular • Innervated • Regenerative

18. Classification of Epithelium-based on number of layers and cell shape • Layers • Simple • Stratified • Psuedostratified • Stratified layers characterized by shape of apical layer • Shapes • Squamous • Cuboidal • Columnar • Transitional

19. Simple squamous (1 layer) Lungs, blood vessels, ventral body cavity Simple cuboidal Kidney tubules, glands Simple columnar Stomach, intestines Pseudostratified columnar Respiratory passages (ciliated version) Stratified squamous (>1 layer) Epidermis, mouth, esophagus, vagina Named so according to apical cell shape Regenerate from below Deep layers cuboidal and columnar Transitional (not shown) Thins when stretches Hollow urinary organs Types of Epithelium All histology pictures property of BIOL 1010 Lab

20. Endothelium Simple squamous epithelium that lines vessels e.g. lymphatic & blood vessel Mesothelium Simple squamous epithelium that forms the lining of body cavities e.g. pleura, pericardium, peritoneum Endothelium

21. Features of Apical Surface of Epithelium • Microvilli:(ex) in small intestine • Finger-like extensions of the plasma membrane of apical epithelial cell • Increase surface area for absorption • Cilia: (ex) respiratory tubes • Whip-like, motile extension of plasma membrane • Moves mucus, etc. over epithelial surface 1-way • Flagella:(ex) spermatoza • Extra long cilia • Moves cell www.colorado.edu/.../020digestion.htm

22. Features of Lateral Surface of Epithelium • Cells are connected to neighboring cells via: • Proteins-link cells together, interdigitate • Contour of cells-wavy contour fits together • Cell Junctions (3 common) • Desmosomes • adhesive spots on lateral sides linked by proteins/filaments • holds tissues together • Tight Junctions • at apical area • plasma membrane of adjacent cells fuse, nothing passes • Gap junction • spot-like junction occurring anywhere made of hollow cylinders of protein • lets small molecules pass

23. Features of the Basal Surface of Epithelium • Basement membrane • Sheet between the epithelial and connective tissue layers • Attaches epithelium to connective tissue below • Made up of: • Basal lamina: thin, non-cellular, supportive sheet Made of proteins • Superficial layer • Acts as a selective filter • Assists epithelial cell regeneration by moving new cells • Reticular fiber layer • Deeper layer • Support

24. Glands • Epithelial cells that make and secrete a product • Products are water-based and usually contain proteins • Classified as: • Exocrine • Endocrine • Uni-/multicellular Page 116

25. Glands: epithelial cells that make and secrete a water-based substance w/proteins • Exocrine Glands • Secrete substance onto body surface or into body cavity • Activity is local • Have ducts (simple vs. compound) • Unicellular (goblet cells) or Multicellular (tubular, alveolar, tubuloalveolar) • (ex) salivary, mammary, pancreas, liver

26. Glands: epithelial cells that make and secrete a water-based substance w/proteins • Endocrine Glands • Secrete product into blood stream • Either stored in secretory cells or in follicle surrounded by secretory cells • Hormones travel to target organ to increase response (excitatory) • No ducts • (ex) pancreas, adrenal, pituitary, thyroid

27. 4 Types of Tissue • Epithelium • Connective • Muscle • Nervous

28. 4 Types of Connective Tissue Connective Tissue Proper Cartilage Bone Tissue Blood

29. Connective Tissue (CT): most abundant and diverse tissue • Four Classes • Functions include connecting, storing & carrying nutrients, protection, fight infection • CT contains large amounts of non-living extracellular matrix • Some types vascularized • All CT originates from mesenchyme • Embryonic connective tissue

30. 1) Connective Tissue Proper • Two kinds: Loose CT & Dense CT • Prototype: Loose Areolar Tissue • Underneath epithelial tissue • Functions • Support and bind to other tissue • Hold body fluids • Defends against infection • Stores nutrients as fat • Each function performed by different kind of fiber in tissue

31. Fibers in Connective Tissue • Fibers For Support • Reticular: • form networks for structure & support • (ex) cover capillaries • Collagen: • strongest, most numerous, provide tensile strength • (ex) dominant fiber in ligaments • Elastic: • long + thin, stretch and retain shape • (ex) dominant fiber in elastic cartilage

32. In Connective Tissue Proper • Fibroblasts: • cells that produce all fibers in CT • produce + secrete protein subunits to make them • produce ground matrix • Interstitial (Tissue) Fluid • derived from blood in CT proper • medium for nutrients, waste + oxygen to travel to cells • found in ground matrix • Ground Matrix (substance): • part of extra-cellular material that holds and absorbs interstitial fluid • Made and secreted by fibroblasts • jelly-like with sugar & protein molecules

33. Defense from Infection • Areolar tissue below epithelium is body’s first defense • Cells travel to CT in blood • Macrophages-eat foreign particles • Plasma cells-secrete antibodies, mark molecules for destruction • Mast cells-contain chemical mediators for inflammation response • White Blood Cells = neutrophils, lymphocytes, eosinophils-fight infection • Ground substance + cell fibers-slow invading microorganisms

34. Specialized Loose CT Proper • Adipose tissue-loaded with adipocytes, highly vascularized, high metabolic activity • Insulates, produces energy, supports • (eg) in hypodermis under skin • Reticular CT-contains only reticular fibers • Forms caverns to hold free cells • (eg) bone marrow, holds blood cells • Forms internal “skeleton” of some organs • (eg) lymph nodes, spleen

35. Dense/Fibrous Connective Tissue • Contains more collagen • Can resist extremely strong pulling forces • Regular vs. Irregular • Regular-fibers run same direction, parallel to pull • (eg) fascia, tendons, ligaments • Irregular-fibers thicker, run in different directions • (eg) dermis, fibrous capsules at ends of bones

36. Components of CT Proper Summarized

37. 2) Cartilage • Chondroblastsproduce cartilage • Chondrocytes mature cartilage cells • Reside in lacunae • More abundant in embryo than adult • Firm, Flexible • Resists compression • (eg) trachea, meniscus • Avascular (chondrocytes can function w/ low oxygen) • NOT Innervated • Perichondrium • dense, irregular connective tissue around cartilage • growth/repair of cartilage • resists expansion during compression of cartilage

38. Cartilage in the Body • Three types: • Hyaline • most abundant • fibrils in matrix • support via flexibility/resilience • (eg) at limb joints, ribs, nose • Elastic • many elastic fibers in matrix too • great flexibility • (eg) external ear, epiglottis • Fibrocartilage • resists both compression and tension • (eg) meniscus, annulus fibrosus

39. Components of Cartilage Summarized

40. Histology of Cartilage • Hyaline Cartilage

41. Histology of Cartilage • Elastic Cartilage

42. Histology of Cartilage • Fibrocartilage www.indigo.com/software/gphpcd/his49-52.html

43. 3) Bone Tissue:(a bone is an organ) • Well-vascularized • Function: • support (eg) pelvic bowl, legs • protect (eg) skull, vertebrae • mineral storage (eg) calcium, phosphate (inorganic component) • movement (eg) walk, grasp objects • blood-cell formation (eg) red bone marrow

44. Bone Tissue • Osteoblasts • Secrete organic part of bone matrix • Osteocytes • Mature bone cells • Maintain bone matrix • Osteoclasts • Degrade and reabsorb bone • Periosteum • External layer of CT that surrounds bone (except at joints) • Endosteum • Internal layer of CT that lines cavities and covers trabeculae academic.kellogg.cc.mi.us/.../skeletal.htm

45. External layer Osteon (Haversian system) Parallel to the long axis of the bone Groups of concentric tubules (lamella) Lamella = layer of bone matrix where all fibers run in the same direction Adjacent lamella fibers run in opposite directions Haversian Canal runs thru center of osteon Contains BV and nerves Compact Bone www.mc.vanderbilt.edu/.../CartilageandBone03.htm

46. Bone Anatomy: Spongy bone • Spongy bone (cancellous bone): internal layer • Trabeculae: small, needle-like pieces of bone form honeycomb • each made of several layers of lamellae + osteocytes • no canal for vessels • space filled with bone marrow • not as dense, no direct stress at bone’s center Pg 123

47. Shapes of Bones • Flat = skull, sternum, clavicle • Irregular = pelvis, vertebrae • Short = carpals, patella • Long = femur, phalanges, metacarpals, humerus

48. Anatomy of a Long Bone • Diaphysis • Medullary Cavity • Nutrient Art & Vein • 2 Epiphyses • Epiphyseal Plates • Epiphyseal Art & Vein • Periosteum • Outer: Dense irregular CT • Inner: Osteoblasts, osteoclasts • Does not cover epiphyses • Attaches to bone matrix via collagen fibers • Endosteum • Osteoblasts, osteoclasts • Covers trabeculae, lines medullary cavity training.seer.cancer.gov/.../illu_long_bone.jpg

49. 2 Types of Bone Formation • Endochondral Ossification: All other bones • Begins with a cartilaginous model • Perichondrium becomes replaced by periosteum • Cartilage calcifies • Medullary cavity is formed by action of osteoclasts • Epiphyses grow and eventually calcify • Epiphyseal plates remain cartilage for up to 20 years • Intramembranous Ossification • Membrane bones: most skull bones and clavicle • Osteoblasts in membrane secrete osteoid that mineralizes • Trabeculae form between blood vessels, thickens to become compact bone at periphery • Osteocytes maintain new bone tissue • Periosteum forms over it

50. Bone Growth & Remodeling • GROWTH • Appositional Growth = widening of bone • Bone tissue added on surface by osteoblasts of periosteum • Medullary cavity maintained by osteoclasts • Lengthening of Bone • Epiphyseal plates enlarge by chondroblasts • Matrix calcifies (chondrocytes die and disintegrate) • Bone tissue replaces cartilage on diaphysis side • REMODELING • Due to mechanical stresses on bones, their tissue needs to be replaced • Osteoclasts-take up bone ( = breakdown) release Ca2++ , PO4 to body fluids from bone • Osteoblasts-form new bone by secreting osteoid • Ideally osteoclasts and osteoblasts work at the same rate!