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ANATOMY AND PHYSIOLOGY LECTURE -
Organization of Cell Structure
Doc. Milliem Reyes|1st^ Semester | BSMLS-1K
CELLS โ Building Blocks of Life โ Maintain proper homeostasis โ Basic living, structural, and functional unit of the body. Cells carry out many functions that help each system contribute to the homeostasis of the entire body. โ CYTOLOGY (cell biology): The scientific study of cells. TWO MAJOR TYPES OF CELL โ PROKARYOTIC CELL โข Surrounded by membrane โข DNA is naked, nucleud โข Only have 1 DNA na dit is circular EUKARYOTIC CELL โข membrane bound organelles โข DNA is enclosed, nucleus โข Several chromosomes SHAPE OF CELLS โ BICONCAVE DISC โ example are blood cells where it has depression on both sides so it is easy to go through veins โ BRANCHED โ nerve cell โ VARIABLE โ the shape cary on their fucntion. (macrophages/white blood cell) SIZE OF A CELL Smallest Sperm Cell Size 5um Largest Ovum Cell Size 120um Longest Cell Nervous cell Size 1m WHITE BLOOD CELL โ NEUTROPHIL โ lots of lobules, lobulated neclues โ EOSINOPHIL
PROKARYOTIC
CELL
EUKARYOTIC CELL
Organism Bacteria and cynobacteria Plants, animals and fungi Cell Wall Yes No(animals) Yes(plants) Centrioles No Yes(all animals and some lower plant forms) Cillia and Flagella Do not divide by mitosis and meiosis; they divide by binary fusion Complex cilia and flagella because they use these as the mode of movement Golgi Complex No Golgi complex Yes, Membrane bound organelles Lysosomes No Common in animals No in plants Peroxisomes No Yes Nucleus No Yes Plasma Membrane Yes Yes Chromosomes One long DNA strand Several Chromosome
โ bilobe nucleous โ The red spots are eosinophilic granule โ BASOPHIL โ acidic that explains the color purple of the nucleus and it is also called the irregular nucleuos PRINCIPLE PARTS OF A CELL PLASMA MEMBRANE โ Outermost cover โ Phospholipid bilayer โ Selectively permeable (a selective type that can pass through the membrane) โ Surrounds and contain the cytoplasm of the cell. โ forms the cell's flexible outer surface, separating the cells internal environment (and everything inside the cell) from the external environment (everything outside the cell). โ Fluid mosaic model: โ Best structural model of plasma membrane, according to this model the molecular arrangement of plasma is like a moving sea of fluid lipids that contains a moscaic of mane different protiens. โ Fluidity, the cell membrane can be very flexible and adaptive to any conditions โ Cholesterol is the cause of this fluidity. โ When it is warm it maintain the phospholipids from going apart โ When it is cold it avoids tight packing โ Cholesterol โ support and stability โ fluidity of the membrane (found in betweens of the phospholipids) โ It keeps the cell membrane together โ Glycolipids and Glycoprotiens โ Cell-cell recognition โ receptors STRUCTURAL OF THE PLASMA MEMBRANE โ LIPID BILAYER โ Amphibic molecule โ The basic structural framework of plasma membrane or the cell โ Two back to back layers made up of three types of lipids molecules; phospholipids, cholesterol, and glycolipids โ The bilayer arrangement occur because the lipids are Amphipathic. โ has a hydrophilic portion (water loving, facing outward) โ hydrophobic portion (hate water, facing inward) โ PHOSPHOLIPIDS โ 75% of the membrane lipids and contain phosphorus โ CHOLESTOREL โ 20% โ GLYCOLIPIDS โ 5% with attached catbohydrates
โ Isotonic โ normal concentration, equal inside and outside of the cell โ Hypotonic โ Low concentration outside of the cell, the water then goes inside the cell to balance i out and it causes the cell to swell and burst โ The rupture of RBCs in this manner is called hemolysis โ Hypertonic solution โ from inside the cell it will go out to high concentration (exp. salt water) FACILITATED DIFFUSION โ requires a carrier (also called a transporter) โ move a solute down its concentration gradient across the plasma membrane โ The number of carriers available in a plasma membrane places an upper limit, called the transport maximum, on the rate at which facilitated diffusion can occur. โ High to low concentration ACTIVE TRANSPORT โข It needs energy ATP, which goes against the concentration gradient. โข Energy is required for carrier proteins to move solutes across the membrane against a concentration gradient. PRIMARY โ energy derived from the hydrolysis of ATP changes the shape of a car rier protein, which โpumpsโ a substance across a plasma mem brane against its concentration gradient. โ Goes against the concentration gradient โ Uses up ATP directly (atp currency) โ PUMP- Active transport, carrier proteins that mediate primary active transport SECONDARY โ Co-transporters, Antiporter โ Does not use ATP and concentration gradient โ Electrochemical gradient(transport of ions) followed by the cell like a circuit โ ex. Sodium potassium chloride (sodium and potassium are very good ions chemical gradient) โ Mechanisms use the energy stored in an ionic concentration gradient CYTOPLASM โข Cytoplasm consists of all the cellular contents between the plasma membrane and the nucleus. โข All cellular contents between the plasma membrane and the nucleus
TWO MAJOR COMPONENTS CYTOSOL โ (intracellular fluid) gell-like fluid, a fluid portion of the cytoplasm that surrounds organelles and constitutes about 55% of total cell volume. โ Viscous and semitransparent โ contain the membrane-bound organelles, which are the sites of many chemical reactions required for a cellโs existence. (glycolysis) ORGNALLES โ โlittle organsโ โ specialized structures within the cell that have characteristic shapes; they perform specific func tions in cellular growth, maintenance, and reproduction. โ Metabolic machinery of the cell โ Membranes vs Non-membranes CYTOSKELETON (NM) โ Network of protein filament โ For cell shape and placement organelles โ MICROFILAMENTS โ thinnest 7mm โ composed of the protein actin and are most prevalent at the edge of a cell โ help generate movement and provide mechanical support. โ INTERMEDIATE FILAMENTS โ 10mm, keratin, vimentin โ They are found in parts of cells subject to mechanical stress, help stabilize the position of organelles such as the nucleus, and help attach cells โ Epithelium- Keratin, Mesargimon tissue- vimentin, Smooth striated muscle- desmin, Nerve cell- Neuro filament, Inner nuclear membrane- Lamin โ MICROTUBULES โ The thickest 25mm, composed mainly of the protein tubulin โ It forms centrosome, which is very important for cell division CILIA AND FLAGELLA โ Cillia โ are numerous, short, hairlike projections that extend from the surface of the cell โ Moves fluid cell or particular matter, flap back and forth. โ sweep mucus (archea), sweep egg/zygote toward the uterus โ Flagella โ typically much longer. โ Flagella usu ally move an entire cell. A flagellum generates forward motion along its axis by rapidly wiggling in a wavelike pattern
โ Lamins: โ line the inner nuclear membrane, made of intermediate filaments โ Nuclear Pore โ where products from the nucleus pass through ENDOPLASMIC RETICULUM (M) โ Network of folded membranes โ where ribosomes attach to โ Ribosomes associated with endoplasmic reticulum synthesize proteins destined for insertion in the plasma membrane or secretion from the cell. โ CISTERNAE : โ the folded part, sacs of double membranes of the smooth and rough ER โ Rough ER : โ Covered by ribosomes โ continues with the nuclear membrane โ site for protein synthesis โ Nissl Substance: โ RER + free ribosome in neurons โ also called as tigroid, looks like a tiger โ granular body in neurons
โ Smooth ER : โ no ribosome = no stain โ usually continues with the RER โ Synthesis and storage of lipids โ Inactive and detoxifies drugs and other potentially harmful substances โ abundant in certain types of cell (oil glands) โ ex. liver (hepatosites) detoxifies harmful substances GOLGI APPARATUS (M) โ Protein packaging plant of your cell โ Modifies, sorts, packages, and transports proteins received from the rough ER. โ Also made up of cisternae with bulging edges โ Cisface( entry)- protein goes here โ Medial cisternae - Sacs between the entry and exit faces โ Transface (exit) โ For movement of materials in and out of the cell โ Modified of proteins MITOCHONDRIA โ Powerhouse of the cell โ sausage-shaped with folded membranes ( Cristae ) โ generate most of the ATP through aerobic (oxygen-requiring) respiration, found in the muscles, liver, and kidneys, which use ATP at a high rate โ you cant find mitochondria in red blood cells โ The function is to generate ATP โ oxidative phosphorylation โ Calcium storage and homeostasis โ Involved in programmed cell death โ Outer membrane โ more permeable โ Inner membrane โ has Cristea โ Site of ATP synthesis โ Fluid-filled space
INCLUSION BODIES โ not organelles โ contain accumulated metabolites or other substances โ have little or no metabolic activity โ produced by the cell, and it stays, but it's not an organelle LIPID DROPLETS โ Accumulation of fat โ usually found in adpocytes but can be seen in other cells GLYCOGEN GRANULES โ the storage form of glucose โ Irregular clumps of periodic acid-Schiff stain under the microscope โ seen in liver(hepatocyte) and muscle(myocyte) cells PIGMENTED DEPOSITS โ Melanin (natural sunblock) โ Lipoducsin (wear and tear pigment โ Henosiderin (denatured ferritin protein with many bound iron atoms) Tortora and Derrickson, G., and B. (2008). Principles of Anatomy and Physiology (12th ed.). John Wiley's and Sons, Inc. PPT prepared by Doc. Millem Reyes and her discussion REFERENCES:
