1/22 Notes Eye can view 200 micons (10-6) Light microscope can view 0.2 microns Electron microscope can view 1-2 nanometers Heterochromatin- inactive DNA (DNA not being actively transcribed into RNA); dark condensed areas Euchromatin- active DNA; transparent patches Secretory granules- black spots in cell that signify protein is being made Golgi apparatus- synthesis, packaging for transport, production lysosomes and proteins Endoplasmic reticulum- mechanical support, protein synthesis, and transport Nucleolus- production and assembly of ribosomes Ribosome- produce proteins Mitochondria- ATP production The more infoldings (and dense) within the mitochondria the more ATP production DNARNAmRNAmRNA affiliates w/ ribosomes and becomes protein OR mRNA affiliates with rough ER golgi apparatus secretory granules Phospholipids group is known as a trilaminar structure Membrane raft- help organize what is going on in a membrane. "A raft of proteins in a sea of phospholipids." Lab 1/24 The Classic Hematoxylin Very basic, positively charged, binds to acids Stains- DNA, RNA, nucleus, ribosomes, rough ER Blue-purple color Eosin Very acidic, binds to bases Stains- cytoplasmic proteins, cytoplasm, extracellular space Pink color Hematoxylin and eosin staining is often used to detect inflammation or to determine the integrity of a tissue. The Basics Toluidine or Nissle Blue Similar to H&E; usually used for mast cells Sweetness Periodic acid Schiff (PAS) Stains- complex carbohydrates, glycogen, extracellular matrix, muscin Routine stain for liver or kidney Bright red color
True Colors Masson Trichrome Black or brown nuclei Red keratin and muscle fibers Blue or green collagen and bone (extracellular matrix) Light red or pink cytoplasm Heavy Metal Silver and Gold Brown or black intracellular organelles or entire cell Notes 1/29 Camillo Golgi believed that all the neurons in a cell were connected to one big network. Ramon y Cajal believed that all the cells were separate and that is why only some cells stained while others did not. 1. Cellular Organelles: Vesicles- can be both clear and dark Lysosomes- membrane-bound organelles containing enzymes. They are like the garbage disposals of the cell. Acid phosphate is an enzyme located within the lysosome. Histochemical label (add substrate to enzyme) is restricted to just the lysosome and not to the mitochondria or ribosomes. Peroxisomes (microbodies)- small, membrane-bound organelles that resemble lysosomes. They contain oxidases, which aids in the formation of hydrogen peroxide. Hydrogen peroxide is used to kill ingested microorganisms. Peroxisomes also contain catalase, which regulates hydrogen peroxide concentration. 2. Cellular Inclusions: Glycogen granules- non membrane-bound granules and aggregates of granules used for energy storage. Glycogen is important for metabolism and energy production. Lipid droplets- round accumulations of fat and have no well defined membrane. Osmic acid is a heavy metal that stains lipids. Pigment- is made from different compounds and is located in a membrane-bound compound. Lipofuscin is an intracellular pigment. With increasing age, lipofuscin accumulates in brown granular material in the cytoplasm and ganglion cells. Melanin is another natural pigment responsible for skin color. Melanin is also located in nerve cells. 3. Transportation Endocytosis- when cells take up particulate matter and large macromolecules (proteins) by a variety of processes. Phagocytosis- used by cells of the defense system to ingest and kill pathogenic organisms. The membrane folds around the object, and the object is sealed off into a large vacuole known as a phagosome.
Exocytosis- is a process in which an intracellular vesicle moves to the plasma membrane and subsequent fusion of the vesicular membrane and plasma membrane ensues. 4. Types of Microscopy Brightfield- normal microscope DIC- polarized light to generate shadowcast; gives a 3 dimensional view Darkfield- the light comes from an angle as a result the ell can be seen better due to the light refracting of the granules within Phase contrast- manipulates light; leaves a white circle around cell Fluorescence- light source is to the side (above the specimen) light is deflected toward the specimen first barrier filter only allows a certain color light (certain wavelength) to go through beam splitting mirror reflects light below a certain wavelength and only allows light above a certain wavelength second barrier cuts out unwanted fluorescence signals so only green light (with another wavelength) is allowed to pass 5. Cytoskeleton Maintains the shape and polarity of the cell Microfilaments- are extremely fine strands of the protein actin. Actin filaments are in the skeletal muscle. Actin plays an important role in cell movement and phagocytosis. Intermediate filaments- (also known as neurofilaments) provides internal support for the cell. There are different intermediate filaments for different cells. Eg. Cytokeratin- epithelial cells form a supporting network within the cytoplasm and are anchored to the plasma membrane Desmin- muscle cell, neurofilaments- neurons, vimentin- menenchymal cells, GFAP- glial cells Microtubules- are made up of globular protein subunits, which can be assembled and disassembled. Centriole is the organizing center for microtubules. Microtubules radiate outwards from the centrioles. Centrosome typically stays next to the nucleus and the golgi apparatus stays close to centrosome. Random Notes: Polymorphic nucleus- small lobes everywhere within the cell Notes 2/5 Mitochondria and nucleolus are maternally inherited Centriole is paternally inherited Cell Cycle 1. Chromosome replication 2. Chromosome segregation 3. Cell division M, G1, S, G2 M=cytokinesis; mitosis
S= DNA replication; synthesis G1=growth; cells differentiate and perform their specialized functions G2= waiting; prepare for mitotic division G0= continuous differentiated function Cyclin protein peaks during M phase Apoptosis- programmed cell death 1. Cell receives signal to begin apoptosis 2. Condensation of nuclear chromatin, cell shrinks away from neighbors 3. Nuclear material breaks into fragments 4. Begin to break away from cell surface 5. Entire cell breaks up to form membrane-bound fragments Necrosis- mode of cell and tissue death Caused by disease or injury; cell releases toxic contents into tissues Small Intestine Epithelial tissue- absorption of nutrients; also gives protection Eg. Lining in the intestinal cavity (intestinal epithelium) lining of the outer surface of the organ (mesothelium) Muscle tissue- peristalsis Connective tissue- fills in the space and acts like a stabilizer Eg. Lamina propria (loose), submucosa (dense) Nerve tissues- regulate contractions Eg. Parasympathetic ganglia and neurons forming plexuses Lymphatic tissue- helps protect the intestine Eg. Lymphocytes and plasma cells Notes 2/12 Types of epithelial Simple- a single layer of epithelial cells Stratified- several layers of epithelial cells Pseudostartified- a single layer with the impression of multiple layers Shape of epithelial Squamus (flattened), cuboidal, and columnar Transitional epithelium- form of stratified epithelium found only in the urinary tract Junctions Epithelial Tight junctions- block the passage of molecules between adjacent cells Zonula adherens and desomeres- give the epithelium strength by linking the cytoskeletons of adjacent cells Contain cadherin protein, which helps actin interact through the membrane. Gap junctions- provides a conduit for the passage of small molecules directly between the adjacent cells and provide communication between the cells Cilia are motile structures that project from the apical surfaces of certain epithelial cells. They are composed of nine microtubule doublets and a basal body.
Microvilli (brush borders)- fingerlike projections of the luminal plasma membrane Sterocilia- extremely long microvilli Goblet cell- secretory purpose, full of rough ER, large golgi Notes 2/19 Red blood cells (Erythrocytes)- oxygen and carbon dioxide transport. No nucleus, reddish-grey cytoplasm, biconcave disk shape. White blood cells (leucocyte) Granulocytes- prominent cytoplamsic secretory granules, single multilobed nucleus Neutrophils- most common type of white blood cell, highly motile, phagocytic, kill bacteria, chomtactic (track things), highly lobulated (usually 5 lobes when mature), highly condensed chromatin, different types of membrane-bound granules (which contain antimicrobial proteins), secretory granules Eosinophils- produced by bone marrow, larger than neutrophil, granules stained bright red, cytoplasm pink and clear, antiparasitic function Basophils- least common, formed in the bone marrow, deep blue football-shaped granules Mononuclear leucocytes- non-lobulated nucleus, have important roles in body defense system Lymphocyte- smallest white blood cell, second most common, immunological defense, round densely stained nucleus, no lobes in nucleus, secrete antibodies Monocyte- largest white blood cell, phagocytic, indented nucleus, motile RBC series- Young-large, nucleated, blue/grey Mature-small, enucleated, red cytoplasm WBC series- Young-large, round nucleus Mature- small, lobed nucleus Platelets (thrombocytes)- small, non-nucleated cells formed in bone marrow that are very small and appaear as grey specks. Plateletes form plugs to occlude sites of vacular damage, promote clot formation, and secrete factors that modulate coagulation. Purple-stained. Connective tissue Collagen-most abundant protein in the body and is the main fiber type in supporting tissue. Type I collagen- found in supporting tissue, dermis of the skin, tendons, ligaments, and bone. Type II collagen- found in hyaline cartilage and consists of fine fibrils. Type III collagen- makes up fibers known as reticulin, which forms the supporting meshwork of the liver, bone marrow, and lymphoid organs. Type IV collagen- important consistuent of basement membrane Elastin- structural protein, which is arranged as fibers and discontinuous sheets in the extracellular matrix of the skin, lung, and blood vessels. Notes 2/26 Cartilage Types: Hyaline- most common type, has small aggregations of chondrocytes embedded in a mtraix, glass-like appearance, found in nasal septum, larynx, treacheal rings, & ribs. Fibrocartilage- consists of alternating layers of hyaline cartilage matrix and thick layers of dense collagen fibres; made up of fibrous connective tissue arranged in bundles, with cartilage cells between the bundles. Elastic- stain dark, very flexible, found in external ear and external auditory canal, and epiglottis.
Cell Types: Chondroblast- round cartilage precursor cells. Chondocyte- mature cartilage cell that maintain the integrity of the cartilage matrix. Bone Cell Types: Osteoblasts- responsible for bone formation Osteocyte- large inactive osteoblasts trapped within formed bone, assist in nutrition of bone Osteoclast- phagocytic cells that erode bone Types: Compact (cortical)- made up of parallel bony columns, dense and forms the surface of bone, function is to support the body, protect organs, provide levers for movement, and store minerals. Spongy (cancellous)- low density and strength, high surface area, fills inner cavity of long bone, external area contains red bone marrow, most arteries and veins of bone found here. Haversian canals- series of tubes formed around channels formed by lamellae, surround blood vessels and nerve cells throughout the bone, communicate with osteocytes. Notes 3/4 Skeletal Muscle (voluntary)- responsible for the movement of skeleton and organs, multinucleated with nuclei pushed to the side of the fibers, striated due to bands of thick (myosin) and thin (actin) filaments in the fibers. Aerobic-slow twitch/red muscle- more mitochondria and blood vessels. Anaerobic- fast twitch/white muscle, less mitochondria and blood vessels, made for sprinting. Smooth Muscle- fibers are elongated, spindle-shaped cells, cells arranged in sheets or bundles, nucleus centrally located. Cardiac muscle- striated, fibers are long cylindrical cells, binucleated located in the middle of cell, maintain organ dimensions against outside forces, highly resistant to fatigue, large number of mitochondria, Contraction A Sarcomere is basic contractile unit consisting of two myofilaments separated by a Z disc. Thick filament is composed of mysosin and contains the myosin-binding protein C which binds at one end to the thick filament and the other to Actin. Thin filament is composed of actin and is attached to a disc-like zone. . Tropomyosin covers the myosin binding sites of the actin molecules in the muscle cell. The T-tubule system allows for the propagation of nerve-generated signals from the muscle cell membrane to the sarcoplasmic reticulum. Between the T-Tubules is the sarcoplasmic reticulum, which forms a membranous network, which embraces each myofibril. An action potential then travels along T-tubules until it reaches the sarcoplasmic reticulum and allows the flow of calcium ions into the sarcomere. Calcium ions bind with troponin molecules and alter the structure of the tropomyosin, forcing it to reveal the cross bridge binding site on the actin. Notes 3/18 Neuron- cell in the nervous system that process and transmit information In a chemical synapse, the process of synaptic transmission is as follows: when an action potential reaches the axon terminal, it opens voltage-gates calcium channels, allowing calcium ions to enter the terminal. Calcium causes synaptic vesicles filled with neurotransmitter molecules to fuse with the
membrane, releasing their contents into the synaptic cleft. The neurotransmitters diffuse across the synaptic cleft and activate receptors on the postsynaptic neuron. Myelin layer- increase in the speed at which impulses propagate along the myelinated fiber. Myelination also helps prevent the electrical current from leaving the axon. Spinal Cord Most cell bodies are located in the grey matter most processes occur in white matter. Peripheral nerve- composed of one ore more bundles of nerve fibers (fascicles). Smooth muscle cells and blood cells are never found around a nerve Sensory Receptors Pacinian corpuscles- nerve endings in the skin that are responsible for deep pressure touch and high frequency vibraion. Onion-like structure with neuron in the middle. Meissner's corpuscles- nerve ending in the skin responsible for sensitivity to light touch.