Lesson 1 introduction to human anat and cell structure


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Lesson 1 introduction to human anat and cell structure

  1. 1. Introduction to HumanAnatomy and Cell biology Dr. Obimbo MM MBChB, MSc. Dip Felasa C, PhD (c)
  2. 2. Anatomical Etymology• Anatomy- Science of the structure of body• Greek ‘anatome’- ana – up, tome – cutting• Latin ‘dissecare’ – dis – asunder, secare – cut (dissection)• Anatome = dissecare• Study of Anatomy introduces students to greater terminology
  3. 3.  Anatomy is to Physiology, as Geography is to History Emphasis should be placed on the Anatomy of living body ◦ Surface Anatomy ◦ Radiological Anatomy Major divisions of Anatomy ◦ Gross ◦ Microscopic ◦ Embryology ◦ Neuroanatomy
  4. 4. • Anatomy may be studied systematically or regionally (topographical)• Body systems – Name??• Body topography – ??
  5. 5. Rules Guiding etymology• 1. Each structure shall be designated by one term• 2. Every term in official list shall be in Latin• 3. The term shall primarily be for memory signs• 4. No usage of eponyms
  6. 6. Anatomical Position and Direction
  7. 7. • The body standing erect, facing forward, feet together, toes pointed slightly apart, hands at one’s side, palms facing forward.• Once the body is in this position (or imagined to be in this position,) the positional terms can be used correctly.
  8. 8. Terms• Medial/ lateral – nearer/away median plane• Anterior/posterior – near front/near the back• Superior/inferior – nearer the head/toe – (cf, cranial/caudal/rostral)• Proximal/ distal – limbs• Internal and external – nearer/away from center of an organ (cf, middle)• Superficial/deep• Supine/prone• Ipsilateral/contralateral
  9. 9. Terms of body movement FLEXION: reduces the angle of the joint from the anatomical position. Flex elbow EXTENSION: movement that returns you to anatomical position. Extend elbow. ◦ All these terms refer to either a body part or a joint. HYPEREXTENSION: extension beyond anatomical position; wrist, neck. Some terms relate only to certain areas, such as the ankle: DORSIFLEXION: lift up toes PLANTARFLEXION: move toes down INVERSION: when sole of foot points inward EVERSION: sole of foot points outward. ABDUCTION: move body part away from midline; arm, fingers, thumb ADDUCTION: bring back to midline; arms, fingers, thumb
  10. 10.  ROTATION: pivot on an axis; shake head “no”; can rotate head and shoulder CIRCUMDUCTION: to draw a circle with body part; shoulder, head PRONATION (to lie prone is on stomach). Turn hands downward. SUPINATION: refers to arms; want a bowl of soup, supinate PROTRACTION: to move anteriorily; shoulders, mandible RETRACTION: to move part posteriorly; shoulders ELEVATION: to raise part superiorly; shoulders DEPRESSION: to lower part; open mouth.
  11. 11. Main areas to be studied• Osteology and arthrology• Myology• Angiology• Neurology• Splanchnology• Surface marking/ anatomy
  12. 12. Cell Structure and Function
  13. 13. Chapter Outline• Cell theory• Properties common to all cells• Cell size and shape – why are cells so small?• Eukaryotic cells – Organelles and structure in all eukaryotic cell• Cell junctions
  14. 14. History of Cell Theory• mid 1600s – Anton van Leeuwenhoek – Improved microscope, observed many living cells• mid 1600s – Robert Hooke – Observed many cells including cork cells• 1850 – Rudolf Virchow – Proposed that all cells come from existing cells
  15. 15. Cell Theory1. All organisms consist of 1 or more cells.2. Cell is the smallest unit of life.3. All cells come from pre-existing cells.
  16. 16. Observing Cells• Light microscope – Can observe living cells in true color – Magnification of up to ~1000x – Resolution ~ 0.2 microns – 0.5 microns
  17. 17. Observing Cells• Electron Microscopes – Preparation needed to kill the cells – Images are black and white – may be colorized – Magnifcation up to ~100,000 • Transmission electron microscope (TEM) – 2-D image • Scanning electron microscope (SEM) – 3-D image
  18. 18. SEM TEM
  19. 19. Cell Structure• All Cells have: –an outermost plasma membrane –genetic material in the form of DNA –cytoplasm
  20. 20. Cell Structure• All Cells have: –an outermost plasma membrane • Structure – phospholipid bilayer with embedded proteins • Function – isolates cell contents, controls what gets in and out of the cell, receives signals
  21. 21. Cell Structure• All Cells have: –genetic material in the form of DNA • Eukaryotes – DNA is within a membrane (nucleus) • Prokaryotes – no membrane around the DNA (DNA region called nucleoid)
  22. 22. Cell Structure• All Cells have: –cytoplasm with organelles • Cytoplasm – fluid area inside outer plasma membrane and outside DNA region
  23. 23. Eukaryotic Cells• Structures in all eukaryotic cells – Nucleus – Ribosomes – Endomembrane System • Endoplasmic reticulum – smooth and rough • Golgi apparatus • Vesicles – Mitochondria – Cytoskeleton
  25. 25. Nucleus• Function – isolates the cell’s genetic material, DNA – DNA directs/controls the activities of the cell • DNA determines which types of RNA are made • The RNA leaves the nucleus and directs the synthesis of proteins in the cytoplasm
  26. 26. Nucleus• Structure – Nuclear envelope • Two Phospholipid bilayers with protein lined pores –Each pore is a ring of 8 proteins with an opening in the center of the ring – Nucleoplasm – fluid of the nucleus
  27. 27. Nuclear pore bilayer facing cytoplasm Nuclear envelope bilayer facing nucleoplasm Fig. 4-17, p.61
  28. 28. Nucleus• DNA is arranged in chromosomes – Chromosome – fiber of DNA and the proteins attached to the DNA – Chromatin – all of the cell’s DNA and the associated proteins
  29. 29. Nucleus• Structure, continued – Nucleolus • Area of condensed DNA • Where ribosomal subunits are made – Subunits exit the nucleus via nuclear pores
  30. 30. Endomembrane System• Series of organelles responsible for: – Modifying protein chains into their final form – Synthesizing of lipids – Packaging of fully modified proteins and lipids into vesicles for export or use in the cell
  31. 31. Endomembrane System• Endoplasmic Reticulum (ER) – Continuous with the outer membrane of the nuclear envelope – Two forms - smooth and rough• Transport vesicles• Golgi apparatus
  32. 32. Endoplasmic Reticulum• Rough Endoplasmic Reticulum (RER) • Network of flattened membrane sacs create a “maze” • Ribosomes attached to the outside of the RER make it appear rough
  33. 33. Endoplasmic Reticulum• Function RER • Where proteins are modified and packaged in transport vesicles for transport to the Golgi body
  34. 34. Endomembrane System• Smooth ER (SER) – Tubular membrane structure – Continuous with RER – No ribosomes attached• Function SER – Synthesis of lipids (fatty acids, phospholipids, sterols..)
  35. 35. Endomembrane System• Additional functions of the SER – In muscle cells, the SER stores calcium ions and releases them during muscle contractions – In liver cells, the SER detoxifies medications and alcohol
  36. 36. Golgi Apparatus• Golgi Apparatus – Stack of flattened membrane sacs• Function Golgi apparatus – Completes the processing substances received from the ER – Sorts, tags and packages fully processed proteins and lipids in vesicles
  37. 37. Golgi Apparatus– The proteins and lipids are modified as they pass through layers of the Golgi– Molecular tags are added to the fully modified substances • These tags allow the substances to be sorted and packaged appropriately. • Tags also indicate where the substance is to be shipped.
  38. 38. Transport Vesicles• Transport Vesicles – Vesicle = small membrane bound sac – Transport modified proteins and lipids from the ER to the Golgi apparatus (and from Golgi to final destination)
  39. 39. Endomembrane System• Putting it all together – DNA directs RNA synthesis  RNA exits nucleus through a nuclear pore  ribosome  protein is made  proteins with proper code enter RER  proteins are modified in RER and lipids are made in SER  vesicles containing the proteins and lipids bud off from the ER
  40. 40. Endomembrane System• Putting it all together ER vesicles merge with Golgi body  proteins and lipids enter Golgi  each is fully modified as it passes through layers of Golgi  modified products are tagged, sorted and bud off in Golgi vesicles  …
  41. 41. Endomembrane System• Putting it all together  Golgi vesicles either merge with the plasma membrane and release their contents OR remain in the cell and serve a purpose
  42. 42. Vesicles• Vesicles - small membrane bound sacs – Examples • Golgi and ER transport vesicles • Peroxisome – Where fatty acids are metabolized – Where hydrogen peroxide is detoxified • Lysosome
  43. 43. Lysosomes• The lysosome is an example of an organelle made at the Golgi apparatus. – Golgi packages digestive enzymes in a vesicle. The vesicle remains in the cell and: • Digests unwanted or damaged cell parts • Merges with food vacuoles and digest the contents
  44. 44. Mitochondria (4.15)• Function – synthesis of ATP – 3 major pathways involved in ATP production 1. Glycolysis 2. Krebs Cycle 3. Electron transport system (ETS)
  45. 45. Mitochondria• Structure: – ~1-5 microns – Outer membrane – Inner membrane - Highly folded • Folds called cristae – Intermembrane space (or outer compartment) – Matrix • DNA and ribosomes in matrix
  46. 46. Mitochondria
  47. 47. Cytoskeleton (4.16, 4.17)• Function – gives cells internal organization, shape, ability to move and polarity• Structure – Interconnected system of microtubules, microfilaments, and intermediate filaments • All are proteins
  48. 48. Cytoskeleton
  49. 49. Cell Junctions• Plasma membrane proteins connect neighboring cells - called cell junctions – Plant cells – plasmodesmata provide channels between cells
  50. 50. Cell Junctions (4.18)• 3 types of cell junctions in animal cells 1. Tight junctions 2. Anchoring junctions 3. Gap junctions
  51. 51. Cell Junctions1. Tight junctions – membrane proteins seal neighboring cells so that water soluble substances cannot cross between them • Seen between stomach cells
  52. 52. Cell Junctions2. Anchoring junctions – cytoskeleton fibers join cells in tissues that need to stretch • See between heart, skin, and muscle cells3. Gap junctions – membrane proteins on neighboring cells link to form channels • This links the cytoplasm of adjoining cells
  53. 53. Tight junction Anchoring junction Gap junction
  54. 54. Cell specializationSpecialized cell Function ModificationMuscle cell Contraction MyofilamentsPancreatic acinar cell Synthesis and secretion of RER enzymesKidney tubular cells Ion transport Basal membrane infoldingsMacrophages Intracellular digestion LysosomesSensory cells Transformation of stimuli Membrane receptors into nerve impulsesLeydig Testicular cells Synthesis and secretion of SER testosterone
  55. 55. Tissues• Tissues are collection of cells that subserve specific function• Four fundamental types: – Epithelial – Supporting – Propulsion – Nervous – Composed of cells, intercellular matrix and tissue fluid
  56. 56. Scope of microscopic Anatomy• Cytology• Histology• Organology
  57. 57. The end....• “ No man should marry until he has studied anatomy and dissected at least one woman” Honore de Balzac Thank you!!