The Cell & Cell Organisation Biomedical Science PDF

The Cell & Cell Organisa/on Biomedical Science Coralie Frances GDC Learning Outcomes 1.1.5 Describe relevant and appropriate dental, oral, craniofacial and general anatomy and explain their applica;on to pa;ent management 1.1.6 Describe relevant and appropriate physiology and explain its...

The Cell & Cell Organisa/on Biomedical Science Coralie Frances GDC Learning Outcomes 1.1.5 Describe relevant and appropriate dental, oral, craniofacial and general anatomy and explain their applica;on to pa;ent management 1.1.6 Describe relevant and appropriate physiology and explain its applica;on to pa;ent management Learning Outcomes At the end of the session the student should have a broad understanding of the structure and components of the cell Be able to: Label and state the func;on of the cell & its components Explain the processes of cell division - mitosis and meiosis Understand the abnormali;es of cell growth and func;on Assess your knowledge pre lecture What is cytology? Look at the next slide What is this? Can you iden;fy the structures? What are their func;ons? 4 How did you do? Rate your knowledge on a score of 1-5 (1 least knowledge; 5 greatest knowledge) Con;nue with the PPT to refresh your knowledge then answer the same ques;ons again What are your scores now? 6 Features of the cell Smallest func;onal unit of the body All organisms are made of cells They carry out all vital chemical processes Humans are mul;-cellular Cells are diUeren;ated and adapted for diUerent tasks The order of development Groups of cells TISSUES Groups of ;ssues ORGANS Groups of organs SYSTEMS Cell Structure Plasma membrane Microtubules Cytoplasm Centrioles Nucleus Peroxisomes Mitochondria Ribosomes Golgi Apparatus Rough Endoplasmic Re;culum Smooth Endoplasmic Re;culum Lysosomes MicroYlaments The Human Cell Nucleus The nucleus is a highly specialised organelle that serves as the informa/on processor & administra/ve centre of the cell Features: 1. One nucleus per cell usually 2. Skeletal muscle & some other cells have several 3. Missing from erythrocytes (red blood cells) 4. Largest feature in a cell Nuclear Envelope Bound by a double membrane, the nuclear envelope – outer layer being con;nuous with Endoplasmic Re;culum (ER) Pores in the membrane allow the passage of substances The Nucleus con/nued……. Func/ons: Stores the gene;c material (DNA) Directs all metabolic ac;vi;es of the cell include growth, metabolism, protein synthesis, and reproduc;on (cell division) Involved in cell division Instructs the synthesis of proteins/ribosomes & RNA Plasma (cell) Membrane Par;ally permeable 02 Phospholipids (fa`y substances) Embedded 01 03 Made up of 2 layers With proteins &. 04 carbohydrate molecules Double layer (bilayer) of lipids mostly phospholipids Phospholipids are hydrophilic ("water-loving") at their phosphate ends – facing outwards, and hydrophobic ("water-fearing") along their lipid tail regions – orientated inwards 15 Plasma Membrane Structural Components Some proteins are embedded in the bilayer, while others a`ach to the surface Many proteins play a part in selec/ve transport of substances across the membrane Others act as surface receptors for substances such as hormones, or act as enzymes Func/ons of Membrane & its Proteins Carbohydrate Regulate transport Act as receptors Allows directed molecules provide Contains cell in and out of cell (recogni;on sites) cell or organelle contents immunological e.g. for hormones mo;lity iden;ty Cytoplasm Gela;nous, semi-transparent buid that Ylls most cells & is where metabolic reac;ons occur Mainly water, with many solutes including glucose, proteins & ions Contains many vital cellular chemicals e.g. Na, phosphates, chlorides, amino acids, ATP & storage material – oil droplets Mitochondrion (mitochondria) The ‘powerhouse of the cell’ Outer & inner membranes Cristae: Folded inner membrane allowing maximum surface area for chemical reac;ons to occur Mitochondrion (mitochondria) Involved with cellular aerobic (O2) respira;on- the process by which chemical energy is made available in the cell Energy = ATP (Adenosine triphosphate) is formed from the catabolism of carbohydrates, fats and proteins in the cell Occur in varying numbers, depending on the cell & its func;on, greatest number in cells which are physically & metabolically ac;ve e.g., skeletal muscles Rough Endoplasmic Re/culum (RER) Features: Series of interconnec;ng membranous canals which Covered in ribosomes which 01 enclose ba`ened sacs called make proteins 04 cisternae Extension of outer nuclear Large surface area for chemical 02 membrane reac;ons 03 Func/on of Rough Endoplasmic Re/culum A Produces proteins especially enzymes B Pathway for transport of materials through the cell C Collec;ng & storing synthesized material Providing a structural skeleton D to maintain cellular shape Smooth Endoplasmic Re/culum (SER) Found in large amounts in cells Similar features to RER, which secrete steroids e.g. but no ribosomes adrenal cortex in the kidney Concerned with synthesis of Also contains enzymes for lipids & steroid hormones detoxifying chemicals including drugs and pes;cides Golgi Apparatus Features: Composed of stacks of ba`ened membranous sacs called cisternae Sacs are buid Ylled & pinch oU smaller membranous sacs, called vesicles Normally only 1 Golgi apparatus in each animal cell Func/on of Golgi Apparatus It packages & processes proteins received from the ER into vesicles prior to secre;on Vesicles then deliver them to their des;na;ons e.g., lysosomes or cell membrane Thus it plays a key role in the secretory pathway Golgi Apparatus con/nued……. Func/ons: Producing secretory enzymes e.g. Transpor;ng & diges;ve enzymes storing lipids Receives glyco-proteins Secre;ng carbohydrates Forming lysosomes such as mucin required e.g. in cell wall in secre;ons, by adding produc;on the carbohydrate part to the protein  Lysosomes A secretory vesicle formed by the 1 Golgi apparatus Contain enzymes responsible for degrading 2 proteins & membranes in the cell Aids degrada;on of materials ingested by the cell 3 – due to hydroly;c (diges;ve) enzymes These are kept apart from the cell otherwise 4 they would destroy the contents of the cell Kept inac;ve by an alkaline environment 5 Abundant in cells with a phagocy;c ac;vity e.g. leucocytes within lysosome Lysosomes con/nued…. Func/ons: Digest materials which the cell consumed from the A Autophagy: A process involving the degrada;on of a cell's own environment e.g. bacteria components through the lysosomal. machinery B D They release enzymes outside Autolysis: The destruc;on of a C the cell (exocytosis) in order cell through the ac;on of its to break down other cells own enzymes Recap Can you state what a lysosome is? What are a lysosome’s func/ons? What does apoptosis mean? 29 Lysosome & its func/on If cell damaged beyond repair Lysosomes can help it to self-destruct by apoptosis (programmed cell death) They destroy invading viruses & bacteria They break down excess or worn-out cell parts A lysosome is a membrane bound cell organelle that contains diges;ve enzymes Centrosome Directs organisa;on of microtubules within the cell Comprises a pair of centrioles (small clusters of microtubules) Plays an important part during cell division 31 Centrosome 2 centrioles, cylindrical structures, orientated at right angles to each other Cylindrical structures, held at right angles to one another Act as organisers of the nuclear spindle during cell division  Micro]laments Composed predominantly of a contrac;le protein called ac/n, which is the most abundant cellular protein Fine, thread-like protein Can also carry out cellular Ybres, 3-6 nm in diameter movements including gliding, contrac;on & cytokinesis (the division of cytoplasm following division of a nucleus) Associa;on with the protein myosin is responsible for muscle contrac;on Microtubules Involved in intracellular Cylindrical tubes, 20- transport, e.g. movement of 25 nm in diameter mitochondria Composed of subunits of Form the spindle fibres for the protein – tubulin separating chromosomes during mitosis When arranged in geometric Act as a scaffold to patterns inside flagellae e.g. determine cell shape and cilia, they are used for locomotion Peroxisome A membrane – Contains oxida;ve bound organelle enzymes such as catalase A major func;on is Important in the breakdown of delaying cell ageing fa`y acid molecules Label the diagram & state their func/ons 36 Cell Division Mitosis Process by which a cell duplicates the chromosomes in its cell nucleus - in order to generate two gene(cally iden(cal daughter nuclei (each containing 46 chromosomes) The process of mitosis is complex and highly regulated Mitosis --- Stages: A 1. Interphase 2. Prophase B 3. Metaphase 4. Anaphase C 5. Telophase D E Interphase Cell growth DNA synthesis Chromosome 2 pairs of replicates into – pairs of chroma;ds centrioles appear Early Prophase Each chromosome has two chroma/ds joined at a centromere The mito;c spindle, composed of microtubules and proteins, forms in the cytoplasm The two pair of centrioles move away from one another toward opposite ends of the cell Late Prophase Nuclear envelope breaks up Microtubules that make up the spindle Ybres, reach from each cell pole to the cell's equator Chromosomes /chroma;ds begin to migrate toward the cell centre Metaphase Nuclear membrane disappears completely Two pair of centrioles align at opposite poles of the cell Chromosomes /chroma;ds align at the metaphase plate at right angles to the spindle poles Anaphase The paired chroma;ds in each dis;nct chromosome begin to move apart Once the paired sister chroma;ds separate from one another, each is considered a "full" chromosome, referred to as daughter chromosomes The daughter chromosomes move to the poles at opposite ends of the cell Telophase Nuclei begin to Chroma;n Ybres of form at opposite chromosomes poles uncoil Cytokinesis, the division At the end of of the original cell's cytoplasm, begins before cytokinesis, there the end of mitosis and are two dis;nct completes shortly ajer daughter cells telophase  Videos of mitosis www.youtube.com/watch?v=RNwJbMovnVQ h`ps://www.youtube.com/watch?v=DwAFZb8juMQ 47 Meiosis 01 This type of cell division The ova grow to maturity in occurs in the forma;on of the ovaries of the female and reproduc;ve cells known as the spermatozoa in the testes the gametes - the ova and of the male spermatozoa 02  Ajer division each of the daughter cells has only 23 chromosomes When the ovum is fer;lized the resultant zygote has the full complement of 46 chromosomes, half from the father and half from the mother Stages of Meiosis - Meiosis I Chromosomes of Homologous (similar) The stages are The homologous Homologous pairs divide and the diploid cells chromosomes pair as for mitosis pairs swap some 2 daughter cells are replicate up DNA produced, each with 23 chromosomes only – haploid Stages of Meiosis- Meiosis II Meiosis II is similar to mitosis & 4 daughter haploid cells are produced Video comparing & contras/ng mitosis & meiosis h`ps://www.youtube.com/watch?v=zrKdz93WlVk&vl=en 53 Cellular Transport Transport of substances across cell membranes Passive Transport Ac/ve Transport DiUusion or osmosis uses ATP Bulk Transport pinocytosis or phagocytosis Cell Transport B D A C E 1. Diausion 2. Osmosis 3. Ac/ve Transport 4. Phagocytosis 5. Pinocytosis Diausion DiUusion is the process by which a substance moves from a region of high concentra;on to a region of low concentra;on Rate is variable: Concentra4on gradient, distance, the size of area, structure in path, & size of molecule Osmosis The passage of water down its concentra;on gradient towards equilibrium across a semi permanent membrane Occurs when solute molecules are too large to pass through the pores in the membrane by diUusion YouTube - Osmosis Ac/ve Transport 1 The transport of substances up their concentra;on gradient i.e. from a lower to a higher concentra;on 2 Chemical energy (ATP) drives protein molecules in the membrane that transport substances across the membrane in either direc;on 3 E.g. the sodium-potassium pump maintains homeostasis of electrolytes sodium and potassium Phagocytosis The process by which the cell can obtain par;cles which are too large to be absorbed by diUusion or ac;ve transport White blood cell engul]ng bacterium Pinocytosis ‘Cell drinking’ is very similar to phagocytosis except vesicles are produced called ‘pinocyto(c vesicles’ Used for intake of liquids rather than solids Both pinocytosis & phagocytosis are methods by which materials are taken into the cell in bulk - ENDOCYTOSIS The reverse process materials are removed from the cell e.g. waste products – EXOCYTOSIS YouTube - Cell Membrane, Exocytosis & Endocytosis Abnormal Cell Growth Hyperplasia A term referring to the prolifera;on of cells within an organ or ;ssue beyond that which is ordinarily seen i.e. constant cell division What may cause this? Hypoplasia Underdevelopment or incomplete development of a ;ssue or organ Refers to an inadequate or below-normal number of cells Hypoplasia is a congenital condi;on, while hyperplasia generally refers to excessive cell growth later in life Atrophy The par;al or complete was;ng away of a part of the body Possible causes? Hypertrophy The increase in the volume of an organ or ;ssue due to the enlargement of its Although hypertrophy & component cells (SIZE hyperplasia are two dis;nct MATTERS) process, they frequently occur together Metaplasia The If the s;mulus is removed or ceases, transforma;on 0 of one type of 03 ;ssues return to cell into another 1 their normal pa`ern state Can you give an Generally caused by some sort of 0 0 example inside the mouth? Or abnormal s;mulus 2 4 generally? Dysplasia Generally, consists of an A term used in pathology expansion of immature to refer to an abnormality cells, with a in maturation of cells corresponding decrease within a tissue in the number and location of mature cells Neoplasia The abnormal It usually causes a prolifera;on of lump or tumour cells The growth of this clone of cells exceeds Neoplasms may be & is uncoordinated benign, pre- with the normal malignant or ;ssues around it malignant