* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Anatomy and Physiology
Survey
Document related concepts
Tissue engineering wikipedia , lookup
Cytoplasmic streaming wikipedia , lookup
Biochemical switches in the cell cycle wikipedia , lookup
Cell nucleus wikipedia , lookup
Signal transduction wikipedia , lookup
Extracellular matrix wikipedia , lookup
Cell encapsulation wikipedia , lookup
Programmed cell death wikipedia , lookup
Cell membrane wikipedia , lookup
Cellular differentiation wikipedia , lookup
Cell culture wikipedia , lookup
Cell growth wikipedia , lookup
Organ-on-a-chip wikipedia , lookup
Endomembrane system wikipedia , lookup
Transcript
Anatomy and Physiology Chapter Three: Cells & Tissues Text Pages 55-77 I. The Cellular Basis of Life As you are already aware, cells contain a large percentage of water. In addition to the intracellular water, cells are surrounded by interstitial fluid. This fluid is found between and outside of all cells. What is meant by the phrase “structure reflects function”? II. Anatomy of the Animal Cell A. What are the 3 parts of the cellB. The nucleus Contains & houses the genetic material of the cell. 1. Nuclear envelope (membrane): double membrane, porous, selectively permeable 2. Nucleoplasm: suspends the nucleoli & chromatin 3. Nucleoli: assemble the ribosomes 4. Chromatin: the genetic material in a nondividing cell 5. Chromosome: the genetic material in a dividing cell 1 C. The cytoplasm The “factory” area of the cell. 1. Cytosol: semitransparent fluid inside the cell; suspends the organelles 2. Inclusions: chemical substances within the cell Most are stored nutrients or cell products. 3. Organelles: “machinery of the cell” All organelles are bound by the same plasma membrane that surrounds the cell itself. This compartmentalization of the cell enables it to become more complex and to divide up the cell’s labor. a. mitochondria: produces cellular energy in the form of ATP “powerhouse of the cell” b. ribosomes: made of protein & rRNA site of protein synthesis Some are attached to endoplasmic reticulum (bound) while others are found alone inside the cytosol (bound). c. endoplasmic reticulum: channels within the cell that carry substances (most often proteins) throughout the cell rough ER: cell’s membrane factory How much is found within the cell depends on how much protein a cell makes. smooth ER: Has no role in protein synthesis. The function of SER is to produce cholesterol, metabolize fat & to detoxify drugs within the body. d. golgi apparatus: modifies & packages proteins in the cell e. lysosomes: clean up the cell with digestive enzymes (found in large amounts in leukocytes) Produced by the golgi apparatus. f. peroxisomes: Similar to lysosomes in that they contain powerful enzymes that detoxify harmful, poisonous materials. (ex: alcohol) 2 Are not produced by the golgi apparatus. g. cytoskeleton: “bones & muscles” of the cell give the cell shape & support & provide the cell with a transportation system microfilaments: provide the cell with shape and assist with cell motility (actin & myosin) microtubules: give the cell shape & determine organelle distribution intermediate filaments: form desmosomes (anchoring joints between cells) h. centrioles: made of microtubules direct the production of the spindle that is used for cell division D. cilia: move substances along the surface of the cell E. flagella: movement of an entire cell 3 F. Plasma membrane Discuss the structure in the space below: 4 1. microvilli: finger-like projections that increase the surface area of a cell for absorptive reasons 2. junctions: a. tight junctions: impermeable, bind cells together tightly plasma membrane to plasma membrane b. desmosomes: hold cells together (like skin cells) c. gap junctions: allow cells to communicate 5 III. Cell Diversity The body contains roughly 200 different kinds of cells in it. These 200 different kinds can be grouped into 7 different categories. A. Cell Specializations 1. 2. 3. 4. 5. 6. 7. IV. Cell Physiology A. Membrane Transport Intracellular fluid: nucleoplasm & cytosol Interstitial fluid: fluid outside of the cell “nutrient-rich” Cells must take what it needs from the interstitial fluids. Because the membrane is selectively permeable the movement of materials in & out of the cell is regulated. 1. Passive Transport During passive transport, no energy is used by the cell. a. Diffusion 6 concentration gradient: place were two unlike concentrations meet osmosis: the diffusion of water through the pores in a membrane isotonic solutions: hypertonic solutions: hypotonic solutions See page 69 “IV therapy and Cellular Tonics” simple diffusion: 7 facilitated diffusion: b. Filtration pressure gradient: instead of a concentration gradient 2. Active Transport During active transport, energy in the form of ATP is used by the cell to move materials that are too large or fat insoluble. Active transport is also used to move materials against the concentration gradient (from low to high concentration). a. solute pumping 8 b. bulk transport exocytosis: 9 1. endocytosis: phagocytosis: “cell eating” white blood cells pinocytosis: “cell drinking” aka: bulk-phase endocytosis 10 B. Cell Division The life cycle of a cell = interphase + cell division 1. Interphase During this phase, the cell grows, prepares for cell division and continues to do the job it is supposed to do for the body. 2. Cell Division Cell division = mitosis + cytokinesis a. Mitosis Cells in the human body divide on average every 2 hours! One somatic cells divides into 2 somatic cells each with 46 chromosomes.. 1. Prophase Chromatin coils to form chromosomes. (already been replicated) Centrioles separate and move to the poles of the cell. Spindle apparatus begins to form between the centrioles. The nuclear envelope begins to break down. 2. Metaphase The chromosomes line up in the middle of the cell. 3. Anaphase Sister chromatids are pulled apart and the chromosomes move to the poles of the cell. 4. Telophase “prophase in reverse” 11 b. Cytokinesis Cleavage furrow forms due a contractile ring of microfilaments that pinch the original cell into 2 separate cells. * Some cells skip cytokinesis and the result is a multinucleated cell. (common in the liver) Somatic cells go through mitotic divisions while gametes go through meiosis. What are the differences? This type of division ensures us that when the sperm cell (haploid) fertilizes the egg cell (haploid) that a diploid zygote is formed. C. Protein Synthesis 1. Genes DNA that codes for 1 protein or polypeptide sequence. 1 gene can be anywhere between 300 & 2000 base pairs in length. In DNA, each 3 letter sequence of bases (codon) “codes” for 1 specific amino acid. 2. RNA RNA assists the decoding of DNA in the nucleus & the building of proteins in the cytoplasm of the cell. a. transfer RNA (tRNA)b. ribosomal RNA (rRNA)c. messenger RNA (mRNA)- 12 3. Protein Synthesis a. Transcription mRNA is made from one strand of DNA. Occurs in the nucleus of a cell. Triplets: 3 base sequence on DNA Codons: 3 base sequence on mRNA b. Translation The process when mRNA is read by rRNA & a protein or polypeptide sequence is made. rRNA “reads” each codon. tRNA brings the appropriate amino acid to the ribosome. Amino acids are linked together by strong peptide bonds. Each polypeptide sequence begins with a start codon and ends with a stop codon. 13 14