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NUR 101 Body Structure and Function

Learn about the components of a cell, including cytoplasm, plasma membrane, organelles (such as ribosomes, ER, Golgi apparatus, mitochondria, lysosomes, centrioles, cilia, and flagella), and the structure of DNA. Understand the movement of substances through cell membranes via passive transport (diffusion, osmosis, dialysis, and filtration) and active transport (ion pumps, phagocytosis, and pinocytosis). Explore the concept of tonicity and the structure of DNA.

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NUR 101 Body Structure and Function

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  1. NUR 101 Body Structure and Function MODULE C: CELLS AND TISSUES

  2. CELLS CELLS A. vary considerably in size B. are microscopic C. differ notably in shape

  3. COMPONENTS OF A CELL CYTOPLASMA A. Cytoplasm which contains specialized organelles and is surrounded by a plasma membrane B. Organization of cytoplasmic substances important to life

  4. COMPONENTS OF A CELL PLASMA MEMBRANE 1. Forms outer boundary of cell 2. Thin, two-layered membrane of phospholipids containing proteins 3. Is selectively permeable

  5. CYTOPLASM ORGANELLES Ribosomes Endoplasmic reticulum (ER) Golgi apparatus Mitochondria Lysosomes Centrioles Cilia Flagella

  6. RIBOSOMES • Are very tiny particles found through out the cell • Some are attached to a network of membranous canals called endoplasmic reticulum (ER) ,some are free in the cytoplasm • Make enzymes and other protein compounds -“protein factories”

  7. ENDOPLASMIC RETICULUM (ER): • Form a network of connecting sacs and canals from the nucleus almost to the plasma membrane. • Carry proteins and other substances through the cytoplasm from one area to another • Are both rough and smooth. The rough ER receives and transports newly made proteins and smooth ER makes new membrane

  8. GOLGI APPARATUS • Tiny flattened sacs stacked near the nucleus. • Collect vesicles filled with proteins and other compounds from the smooth ER • Chemically processes the molecules and packages the material in vesicles that move from the golgi apparatus to the plasma membrane and opens to the outside of the cell “chemical processing and packaging center”

  9. MITOCHONDRIA • Made of two membranous sacs one inside the other • Complex, energy releasing chemical reactions occur continuously • Supply most of the power for cellular work “power plants” • Enzymes within the walls use oxygen to break down glucose and other nutrients to release energy required for cellular work

  10. LYSOSOMES • Are membranous walled organelles that in the active state look like small sacs. • Contain chemicals (enzymes) that digest food compounds “ digestive bags” • Also digest other substances such as microbes which protects the cell • Can kill the cell if the digesting enzymes escape from the lysosomes sac into the cell “suicide bags”

  11. CENTRIOLES • Are two rod-shaped structures • Lie at right angles to each other near the nucleus • Participate in cell reproduction

  12. CILIA • Fine almost hair like extensions on the exposed or free surfaces of some cells • Are capable of moving in unison in a wavelike fashion over the surface of a cell.

  13. Flagella • Are single projections extending from cell surfaces • Are much larger than cilia • “Tails” of sperm cells only example of flagella in humans

  14. STRUCTURAL COMPONENTS OF A CELL • NUCLEUS 1. Controls cell because it contains the genetic code- instructions for making proteins, which in turn determine cell structure and function 2. Component structures include nuclear envelop, nucleoplasm, nucleous, and chromatin granules 3. Chromosomes contain DNA

  15. Movement of Substances Through Cell Membranes • PASSIVE TRANSPORT 1. Diffusion Osmosis Dialysis 2. Filtration ACTIVE TRANSPORT 1. Ion pumps 2. Phagocytosis and pinocytosis

  16. Passive Transport Processes • DIFFUSION 1. is the process by which substances scatter evenly throughout an available space without utilizing energy. 2. movement is from high concentration to low concentration 3. specialized examples diffusion : osmosis and dialysis

  17. Passive Transport Processes FILTRATION 1. is the movement of water and solutes through a membrane caused by hydrostatic pressure 2. move water and solutes from an area with higher hydrostatic pressure to an area with lower hydrostatic pressure 3. is the process responsible for urine formation

  18. Active Transport Processes • ION PUMP 1. is a protein structure in the cell membrane called a carrier 2. uses energy from ATP (adenosine triphosphate) to move ions across cell membranes against the concentration gradient (lower concentration to higher concentration) 3. is specific to particular ions

  19. Active Transport Processes • PHAGOCYTOSIS – is the movement of cells or other large particles into the cell by trapping it in a section of plasma membrane. The material then fuses with lysosomes and is destroyed • PINOCYTOSIS- is the movement of fluid and dissolved molecules into the cell by trapping them in a section of plasma membrane that pinches off inside the cell

  20. Movement of Substances Through Cell Membranes • TONICITY • Isotonic is a solution containing an equal level of NACL as a living red blood cell • Hypotonic is a solution containing a lower level of NACL than is found in a living red blood cell • Hypertonic is a solution containing a higher level of NACL than is found in a living red blood cell

  21. DNA STRUCTURE • Large molecule shaped like a spiral staircase • Sugar (deoxyribose) and phosphate units comprise the sides of the molecule • base pairs (adenine-thymine or guanine-cytosine) compose “steps” • Gene is a specific sequence of base pairs within a DNA molecules • Genes dictate formation of enzymes and other proteins by ribosomes thereby indirectly determining a cell’s structure and function, genes are heredity determinants

  22. GENETIC CODE • The coded or stored information in each gene controls protein and enzyme production, enzymes facilitate cellular chemical reactions, and cellular chemical reactions determine cell structure and function and thereby heredity. • DNA with its genetic code is contained in the nucleus of the cell.

  23. Protein synthesis • The process of transferring genetic information from the nucleus into the cytoplasm requires the completion of two steps: • Transcription is the formation of a messenger RNA (mRNA) from a particular DNA gene sequence. mRNA then passes from the nucleus to the cytoplasm • Translation is the synthesis of protein by ribosomes utilizing the information contained in the mRNA molecule to direct choice and sequence of amino acids to form a protein strand and molecule

  24. CELL REPRODUCTION • DNA REPLICATION is a process by which each half of a DNA molecule becomes a whole molecule identical to the original DNA molecule; precedes mitosis • MITOSIS Is a process in cell division that distributes identical chromosomes (DNA molecules) to each new cell formed when the original cell divides. It enables cells to reproduce their own kind, Makes heredity possible

  25. CELL REPRODUCTION • PHASES OF CELL DIVISION (MITOSIS) Prophase Metaphase Anaphase Telophase

  26. PROPHASE : First Phase • Chromatin granules become organized • Chromosomes (pair of linked chromatids) appear • Centrioles move away from the nucleus • Nuclear envelope disappears, freeing genetic material • Spindle fibers appear

  27. METAPHASE : Second Phase • Chromosomes align across center of cell • Spindle fibers attach themselves to each chromatid

  28. ANAPHASE : Third Phase • Centromeres break apart • Separated chromatids now called chromosomes • Chromosomes are pulled to opposite ends of cell • Cleavage furrow develops at end of anaphase

  29. TELOPHASE : FourthPhase • Completed cell division • Two Nuclei and nuclear envelopes appear • Cytoplasm is divided (cytokinesis) • Two fully functional cells, each having identical genetic characteristics are formed

  30. TYPES of TISSUE • EPITHELIAL • CONNECTIVE • MUSCLE • NERVOUS

  31. EPITHELIAL TISSUE Types of Epithelial Tissue • Simple squamous • Stratified squamous • Simple columnar • Stratified transitional • Pseudostratified • Simple cuboidal

  32. CONNECTIVE TISSUE Types of Connective Tissue • Areolar • Adipose • Dense fibrous • Bone • Cartilage • Blood • Hemopoietic

  33. MUSCLE TISSUE • There are three kinds of muscle tissue: • Skeletal (striated voluntary) – Long threadlike cells with multiple nuclei and striations • Cardiac (striated involuntary) Branching interconnected cylinders with faint striations • Smooth (non- striated involuntary visceral) threadlike cells with single nuclei and no striations

  34. NERVOUS TISSUE • Consists of two kinds of cells : Neurons the functional or conducting units and Glia ( neuroglia) the connecting and supporting cells • Is characterized by a cell body and two types of processes: one axon which transmits a nerve impulse away from cell body and one or more dendrites which carry impulses toward the cell body

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