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Histology

Histology. The study of tissues. Homeostasis. Maintenance of a constant internal environment. We Don’t Like Stress. Physiology identifies and studies the mechanisms of homeostasis. Controlled by Two Systems A. B. Levels of Organization. Cells Tissues organs organ system organism.

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Histology

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  1. Histology • The study of tissues

  2. Homeostasis • Maintenance of a constant internal environment. • We Don’t Like Stress. • Physiology identifies and studies the mechanisms of homeostasis. • Controlled by Two Systems • A. • B.

  3. Levels of Organization • Cells • Tissues • organs • organ system • organism

  4. Tissues • groups of cells with a common structure and function • Four categories • epithelial • connective • muscle • nervous

  5. Epithelial tissue • location: outside of body, line organs and cavities • Function: barrier, absorption or secretion • Glandular  secretory portion of gland • 2 types • simple - one layer • stratified - multiple layers • “pseudostratified” appears stratified due to cells of various lengths

  6. Epithelial tissue • Cell Shapes • squamous - floor tiles • cuboidal - dice • columnar - bricks on end

  7. Connective Tissue Basement Membrane Simple Squamous Leaky to allow diffusion/osmosis. Capillaries, alveoli. May be keratinized on body surfaces.

  8. Connective Tissue Stratified Squamous Readily sloughed off. Skin, anus, vagina.

  9. Simple Cuboidal Area of secretion or absorption.

  10. Stratified Cubiodal

  11. Ciliated Columnar Simple Columnar High secretion and absorption, High SA/VOL Lumen of vessel

  12. Pseudostratified Columnar Pseudostratified Ciliated Columnar Some cells do not reach the surface

  13. Connective Tissue • MOST ABUNDANT TYPE OF TISSUE. • binds and supports other tissues, TRANSPORT, FRAMEWORK, STORE ENERGY • cells create a matrix/ web of fibers [Matrix non-living web of fibers.] • 3 kinds of fibers • collagenous fiber - made of collagen • Elastic fibers - Elastin Protein • reticular fibers - Thin collagen fibers

  14. Types connective tissue • loose connective binds epithelia to underlying tissue; holds organs • 1-Fibroblasts- secretes extracellular proteins • 2-Macrophages- amoeboid WBC’s; phagocytosis • 3-Adipose tissue- fat storage; insulation

  15. Types of Connective Tissue • fibrous connective - parallel Bundles of cells • Ligaments, Tendons, • cartilage - collagen in rubbery matrix • bone - mineralized tissue • blood - liquid plasma matrix

  16. Collagen Tough, somewhat flexible protein. Provides the toughness of meats. Very strong, resists longitudinal stress (tensile strength). Underlies epithelial tissue.

  17. Nuclei of Fibroblast Elastic fibers Long threads of elastin. Easily returns to original shape (rubberband). This is from an aorta. Also found in skin and lungs. Small, unbranched. Secreted by fibroblasts.

  18. Loose Connective Tissue (areolar) • Loose web of fibers (all 3) • Fills space between organs (Styrofoam peanuts). Gel-like matrix. • Composed of elastin (elasticity), collagen (strength), reticular fibers (support/form). • Edema: excess interstitial fluid absorbed by LCT

  19. Nuclei of Fibroblast Dense Connective tissue Fibrous Connective Tissue. Bundles of collagenous fibers. Secreted by fibroblasts. Non-elastic. Resists pulling forces Fxn: strong attachment between structures (tendons & ligaments) Tendon

  20. Cartilage Hyaline Elastic cartilage Chondrocyte Large amount of collagen, embedded in chondroitin sulfate. Provide rigid support. Nose, ear, trachea, interverterbral disks. Reduces friction on ends of long bones, absorbs shock

  21. W.B.C. R.B.C’s Blood Neutrophil Eosinophil Connective tissue with liquid matrix (plasma). Two types of cells RBC’s (Erythrocytes) and WBC’s (Leukocytes) Plasma composed of H2O, NaCl, plasma proteins

  22. Nucleus Adipocyte Adipose (FAT) 15% Male body wt. 22% Female body wt.

  23. Osteocytes Bone Support, protection, storage, movement. Haversian System/ Canal Osteocytes produce collagen + calcium phosphate hydroxyapatite

  24. Muscle Tissue • long cells called muscle fibers capable of contracting when stimulated • 3 types • Smooth - involuntary • Skeletal - voluntary • cardiac - walls of heart

  25. Muscle Skeletal Muscle Cardiac Muscle Fxn: Motion, Heat production, maintain posture. Highly specialized for contraction Striated, branched. Intercalated disks to speed impulse. Aka. Voluntary

  26. Smooth Muscle aka: visceral, unstriated. Surround hollow structures (stomach, blood vessels, intestine, bladder.

  27. Nervous tissue • neuron or nerve cell • specialized to transmit nerve impulses • Dendrites: transmit impulses from tips to rest of neuron • Axons: transmit impulses toward another neuron or effector

  28. Neuron and Glial Cells

  29. Nervous Tissue Neuromuscular Junction

  30. Create a presentation: use microscope pictures • Show the All types of epithelial: • simple squamous, simple cuboidal, stratified squamous, simple columnar • tell what they are • where they would be located • SHow types of connective tissue and what they do: • adipose, cartilage, loose connective, ground bone (no longer a ground bone slide) • show the 3 kinds of muscle tissue and how to tell them apart: • Skeletal, cardiac, smooth • Show a neuron - what are the axons and dendrites? - Use a web picture

  31. Organ systems • Organ: organization of tissues • Mesentaries: suspension of organs (connective tissue) • Thoracic cavity (lungs and heart) • Abdominal cavity (intestines) • Diaphragm (respiration) • Organ systems…... • Digestive-food processing • Circulatory-internal distribution • Respiratory-gas exchange • Immune/Lymphatic-defense • Excretory-waste disposal; osmoregulation • Endocrine-coordination of body activities • Reproductive-reproduction • Nervous-detection of stimuli • Integumentary-protection • Skeletal-support; protection • Muscular-movement; locomotion

  32. Regulation of Internal Environment • Interstitial fluid: internal environment of vertebrates; exchanges nutrients and wastes • Homeostasis: “steady state” or internal balance • Negative feedback: change in a physiological variable that is being monitored • response counteracts the initial fluctuation; • i.e., body temperature • i.e., uterine contractions at childbirth

  33. Positive Feedback • Positive feedback: physiological control mechanism in which a change triggers mechanisms that amplify the change;

  34. Metabolism: sum of all energy-requiring biochemical reactions • Size vs. Metabolic Rate • Inverse relationship • Small = high metabolic rate • Large = low metabolic rate • Endotherms: bodies warmed by metabolic heat • Ectotherms: bodies warmed by environment • Basal Metabolic Rate (BMR): minimal rate powering basic functions of life (endotherms) • Standard Metabolic Rate (SMR): minimal rate powering basic functions of life (ectotherms)

  35. Countercurrent exchange • Counter Current -Common process in multiple systems • Heat exchange example

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