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Introduction and Tissues. Human Anatomy BIOL 1010 Liston Campus. 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
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Introduction and Tissues Human AnatomyBIOL 1010 Liston Campus
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
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
Hierarchy of Structural Organization • Chemical level • Atoms combine to make molecules • 4 macromolecules in the body • Carbohydrates • Lipids • Proteins • Nucleic acids
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
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
Hierarchy of Structural Organization • Organ • Made up of tissue • Heart • Brain • Liver • Pancreas, etc…… Pg 158
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
Hierarchy of Structural Organization • Organism • An individual human, animal, plant, etc…… • Made up all of the organ systems • Work together to sustain life
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
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
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
4 Types of Tissue • Epithelium • Connective • Muscle • Nervous
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
EPITHELIAL TISSUE: sheets of cells cover a surface or line a cavity • Functions • Protection • Secretion • Slippery Surface • Absorption • Ion Transport
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
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
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
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
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
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
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
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
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
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
4 Types of Tissue • Epithelium • Connective • Muscle • Nervous
4 Types of Connective Tissue Connective Tissue Proper Cartilage Bone Tissue Blood
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
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
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
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
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
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
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
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
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
Histology of Cartilage • Hyaline Cartilage
Histology of Cartilage • Elastic Cartilage
Histology of Cartilage • Fibrocartilage www.indigo.com/software/gphpcd/his49-52.html
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
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
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
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
Shapes of Bones • Flat = skull, sternum, clavicle • Irregular = pelvis, vertebrae • Short = carpals, patella • Long = femur, phalanges, metacarpals, humerus
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
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
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!