Lecture 02 Cells and Tissues

1. Lecture 02Cells and Tissues

2. Basic functional unit of life is the _______ • All are derived from pre-existing ________ • Bound by selectively permeable membrane • Include various organelles • Membrane bound organelles • Non-membrane bound organelles

3. Cell Membranes • Semipermeable or selectively permeable • What does this mean and why is it important? • Fluid mosaic model of membrane organization • Major components include lipids and proteins • Phospholipids • Cholesterol • Proteins • Attached Carbohydrate • How are these compounds arranged and how does this account for semipermeable nature of membrane?

4. Movement of Substances in and out of cells • Passive – no energy required – substances move from greater to lesser concentration • No carrier required – lipid soluble substances • Carrier or special pore required – polar or water soluble substances • Active – energy required – from lesser to greater concentration • Carrier involved • Endocytosis and Exocytosis

5. 1. Movement of fat soluble substances across a cell membrane from greater to lesser concentration occurs by __________________ 2. Movement of glucose across a cell membrane from an area of greater to lesser concentation occurs by ____________________ transport. 3. Proteins which attach either to the inner or outer surface of a cell membrane are _______________ proteins. 4. An integral or transmembrane protein which allows passage of certain molecules through the membrane may be referred to as a ____________________.

6. Cell Organelles • Cytoplasm • Organelles • Nonmembranous : contact with cytoplasm • Membranous organelles surrounded by one or two lipid bilayer membranes

7. Membrane bound Cell organelles: • Nucleus • Endoplasmic reticulum • Vesicles • Golgi apparatus • Lysosomes • peroxisomes • Mitochondria

8. Nucleus Large organelle with double membrane nuclear envelope Contains 46 human chromosomes outer membrane continuous with rough ER perforated by nuclear pores Nucleolus site of ribosome assembly

9. Non-membrane bound organelles: • Ribosomes • Cytoskeleton • microvilli • Flagella/cilia

10. Cytoskeleton • Lattice of protein fibers extending through cytoplasm: • Functions: • Movement • support • Cell shape • Anchoring/movement of organelles, cell parts • Anchoring cells together • Constantly rearranged

11. Cytoskeletonal Filaments • Microfilaments • thinnest filaments (actin) • Muscle contraction & support microvilli • Intermediate filaments • several different proteins • anchor organelles • Thick filaments • In muscle contain myosin – interact with thin filaments • Microtubules • large cylindrical structures (composed of tubulin) • flagella, cilia & centrosomes

12. Cilia and Flagella • Function: • Movement • adapted to move things out of areas like the respiratory tract • Composition: • Both same basic structure – cilia shorter • Cilia – oars • Flagella - whip • 9+2 arrangement of microtubules – responsible for causing movement

13. Cilia on Airway Epithelium

14. a. Nucleus f. Endoplasmic reticulum b. Mitochondria g. plasma membrane c. Ribosomes h. nucleolus d. Golgi apparatus i. cilia e. Microvilli j. cytoskeleton  ____ 5. a series of folded membranes extending from the nuclear membrane - parts are site of protein synthesis  ____ 6. non-membrane bound organelles, involved in protein synthesis  ____ 7. series of membrane bound sacs, protein modification  ____ 8. a double membrane enclosed structure - involved in cellular energy transformations  ____ 9. membrane extensions which increase membrane surface area  ____ 10. a fluid mosaic structure involving primarily phospholipids and proteins acting as a barrier surrounding the a cell  ____ 11. darkly staining region within the nucleus  ____ 12. extensions from the cell membrane associated with oar-like movements - important for example in the trachea  ____ 13. a network of proteins - involved in anchoring within cells, cells to each other, motility

15. Intercellular Attachment • Tight Junction – impermeable barrier as plasma membrane of adjacent cells join together – found in intestine, kidneys • Gap junction – passageways between adjacent cells form to allow ions, nutrients, etc. to pass between cells – muscle cells • Desmosomes – cell membranes do not join but cells are held together by intercellular filaments

17. Cell Division • Two cell types: • Somatic – arise from mitotic divisions • Sex cells – arise from meiotic division • Frequency of cell division varies with tissue • Important: • during development • In certain tissues through life • Loss in control  cancer • Number of chromosomes in daughter cells

18. Cell Division and The Cell Cycle in Somatic Cells Interphase Normal cell processes Preparation for division (if necessary) Several phases: G1, S, G2 Duplication of organelles and nuclear material Several checkpoints Length of time varies Mitosis Division of nuclear material Continuous process with named phases Cytokinesis = cell division

20. Cell cycle controls – Important in controlling cell division - Result of specific proteins Act at certain points in cell cycle: 1. G1 – favorable conditions? 2. G2 – trigger for beginning of mitosis 3. M – exit mitosis/cytokinesis – enter G1

21. Cancer 1/3 human population affected during lifetime Failure of checkpoint controls – due to mutation of checkpoint protein Causes: mutagens Viral infection P53 – produces critical check point protein – mutation = loss of control = cancer

22. Cell Resources: • Text – chapter 2 • Cellsalive.com • Genetic science learning center – University of Utah (type: ‘Genetic science learning center’ into Google – it is usually the first site to come up)

24. Four Tissue Types Tissue – group of similarly specialized cells performing a similar function. Epithelial Muscle Connective Nervous

25. Histology How we examine tissues: Teased, smeared or squashed samples, scraped – we are looking at whole cells Thin sections – very thin sections of the tissue are made using a microtome after tissue has been either frozen or embedded in some sort of solid substance like wax or plastic – Staining – In either case stains are used so enhance contrast in the specimen

26. Epithelial Tissue Functions: protection, absorption, secretion Cover all virtually all body surfaces, in and out Lack vascular supply Classified based on shape and stacking of cells Generally supported on a basement membrane (& connective tissue)

27. Glands: Epithelial Cells involved in secretion 2 types: Exocrine glands: connected to the surface by tubes (ducts) cells that secrete---sweat, ear wax, saliva, digestive enzymes onto free surface of epithelial layer Endocrine glands: secretion released to bloodstream, not to surface hormones – regulate body processes

28. Structural Classification of Exocrine Glands Unicellular are single-celled glands goblet cells Multicellular glands branched (compound) or unbranched (simple) tubular or acinar (flask-like) shape

30. Functional Classification of Exocrine Glands Merocrine vacuoles transport Apocrine part of cell pinches off holocrine cell lyses, becomes secretion

32. Connective Tissue Most abundant tissue in body Not on free surfaces Cells separated in a matrix (ground substance + fibers) Good nerve & blood supply (except cartilage & tendons) Classified based on matrix components, arrangement and type of protein fibers

34. Connective Tissue Cell Types -Blast type cells = divide & produce matrix (fibroblasts, chondroblasts, & osteoblasts) -Cyte type cells = mature cell that can not divide or produce matrix (chondrocytes & osteocytes) Others: Immune Cells: Adipocytes (fat cells) store fat Plasma cells Mast cells produce histamine that dilate small BV Various stem cells Mesenchyme

35. Connective Tissue Ground Substance • Supports the cells and fibers • Helps determine the consistency of the matrix • fluid, gel or solid • Contains many large molecules • hyaluronic acid is thick, viscous and slippery • condroitin sulfate is jellylike substance providing support • adhesion proteins (fibronectin) binds collagen fibers to ground substance

36. Connective Tissue Fibers Collagen (25% of protein in your body) Resist pulling forces in tendons and ligaments Rope-like Elastin (lungs, blood vessels, ear cartilage) Stretch and recoil – to 150% of length Reticular (spleen and lymph nodes) Network of fibers - support

37. Defective Collagen and Elastin Ostoegenesis imperfecta mutations in the type I collagen gene Ehlers-Danlos Syndrome mutations in type I collagen & other collagen types (III and V) arthritic (joint) disease. mutation in the elastin gene supravalvular aortic stenosis (SVAS – isolated form) narrowing of arteries and disrupted architecture of the aorta due to defective elastin Marfan syndrome Mutations in the fibrillin gene Scurvy Ascorbic (vitamin C) deficiency  defective formation of collagen

38. Connective Tissue Proper – Dense Connective • Dense regular • Ligaments: bone to bone • Tendons: muscle to bone • Aponeurosis: broad, ribbon-like tendons • Elastic tissue: high proportion of elastic fibers – walls of blood vessels • Dense Irregular Connective: • Mesh-like arrangement of fibers • Dermis of skin • Covering of bone: periosteum • Capsule covering internal organs

39. Connective Tissue Proper – Loose Connective • Aeolar connective • Open framework – lacks organized structure • Deep to dermis, epithel. lining of digestive, resp, urin, elsewhere • Adipose • Converted from aeolar on demand • Padding, insulation, energy storage • Cells (adipocytes) largely oil droplets

40. Fluid Connective Tissue Blood Formed elements plasma Lymph Interstitial fluid Lymphocytes + others Further discussion with circulatory system

41. Support Connective Tissue: Cartilage • avascular • Matrix: • proteoglycan - complex of proteins + chondroitin sulfate • Chondrocytes in lacunae • Surrounded by pericondrium

42. Cartilage • Three types: - How do they differ and where are they found? ( see pages 71, 72) • Hyaline cartilage • Elastic cartilage • fibrocartilage

43. Bone = Osseous Tissue • Highly vascular – repairs • Metabolic – high nutrient and oxygen requirement • Dynamic – osteoblasts build while osteocytes break down – hormonal regulation • Collagen fibers coated with inorganic salts • Develops through process of ossification – conversion of fetal hyaline cartilage skeleton • Two basic types: • Compact bone • Spongy bone

44. Musclefurther discussion in later sections Specialized cells containing myosin and actin (protein) fibers which produce contractions or movement Types: Smooth – involuntary – lack striations ----Two types with striations----------- Skeletal – voluntary muscle; have cross striations and responsible for body movement Cardiac – only found in heart – branched cells bound end to end by intercalated discs

45. Nervous Tissue Involved in sensing and conducting and analysis of information Two cell classes: Neurons – which conduct impulses Neuroglia – which support neurons by providing support, protection and nourishment Further Discussion with nervous system

46. Membranes – involve epithelia + connective tissue • Mucous Membranes (sing. = mucosa) • Line body passages to body surface, glandular cells produce mucous • Maintain moist surface • Serous Membranes • Lines internal body cavities, produce watery transudate • Cutaneous membranes • Waterproof and dry, covers body surface • Synovial membrane

47. Connective tissue Layers • Superficial fascia = subcutaneous layer = hypodermis • Beneath the dermis • Deep fascia • Dense connective tissue • Covers groups of muscles of similar function • Subserous fascia: • deep to deep fascia • separates from serous membrane of body cavities

49. Oklahoma Laws Violators can be fined, arrested or jailed for making ugly faces at a dog. Females are forbidden from doing their own hair without being licensed by the state. Dogs must have a permit signed by the mayor in order to congregate in groups of three or more on private property. Oklahoma will not tolerate anyone taking a bite out of another's hamburger. It is against the law to read a comic book while operating a motor vehicle. Whaling is illegal. It is illegal to have the hind legs of farm animals in your boots. Residents are taxed for the furniture in their homes, and any other personal belongings. (Repealed) Cars must be tethered outside of public buildings. (Repealed) Anyone arrested for soliciting a hooker must have their name and picture shown on television. Tattoos are banned. It is illegal to wear your boots to bed. Fish may not be contained in fishbowls while on a public bus. Tissues are not to be found in the back of one's car.