Anatomy Chapter 3
Terms
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- cytology
- the study of cell structure and function
- squamous cells
- thin flat, and often have angular contours when viewed from above. esophagus and cover the skin
- Polygonal cells
- irregularly angular shapes with four, five, or more sides.nerve cells
- Stellate cells
- star like shape. nerve cells
- Cuboidal cells
- cells are squarish and approximately as tall as they are wide. liver cells
- Columnar cells
- taller than they are wider cells and line the intestines
- Spheroid to ovoid
- egg cells and fat cells are this shape (round to oval)
- Discoid cells
- disk shaped, red blood cells
- Fusiform cells
- thick in the middle and tapered toward the ends . smooth muscle
- fibrous
- threadlike shape. skeletal muscle
- cytoplasm
- fluid between the nucleus and surface membrane
- Transmission Electron Microscope
- beam of electrons in place of light can see the ultrastructure
- Scanning electron microscope
- produces dramatic three dimensional images at high magnification and resolution only view surface featrues
- plasma (cell) membrane
- made of proteins and lipids
- cytoskeleton
- a system of protein microfilaments, intermediate filaments, and microtubles in a cell, serving in physical support, cellular movement, and the routing of molecules and organelles to their destination within the cell
- Intracellular fluid (ICF) or cytosol
- clear gel that the organelles and cytoskeletons are embedded in
- extracellular fluid (ECF)
- fluid outside of the cell
- Integral (transmembrane) proteins
- a protein that extends through a plasma membrane and contacts both the extracellular and intracellualr fluid. Have hydrophilic regions in contact with the cytoplasm and extracellualr fluid and hydrophobic regions that pass back and forth through the lipid of the membrane. Most are glycoproteins which are conjugated with oligosaccharides on the extracellular side of the membrane. some float some are anchored to cytoskeleton
- Peripheral proteins
- do not protrude inot the phospholipid layer but adhere to the intracellular face of the membrane. typically associated with an integral protein and tethered to the cytoskeleton
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Receptor
(function of membrane protein) - chemical signals by which cells communicate with each other often cannot enter the target cell, but bind to surface proteins called receptors. Usually specific for one particular messenger, much like an enzyme that is specific to one substrate
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Second messenger systems
(function of membrane protein - a chemical that is produced within a cell (such as cAMP) or that enters a cell (such as calcium ions) in response to the binding of a messenger to a membrane receptor, an that triggers a metabolic reaction in the cell
- Enzymes in plasma membrane
- carry out the final stages of starch and protein digestion in the small intestine, help produce second messengers, and break down hormones and other signaling molecules whose job is done, thus stopping them from excessively stimulating a cell
- Channel protein
- integral proteins with pores that allowpassage of water and hydrophilic solutes through the membrane
- ligand-regulated gates
- respond to chemical messengers
- voltage regulated gates
- changes in electrical potential (voltage) across the plasma membrane
- mechanically regulated gates
- physical stress on a cell stimuli.
- Carriers
- integral proteins that bind to glucose, electrolytes, and other solutes and transfer them to the other side of the membrane.
- molecular motors
- these proteins produce movement by changing shape and pulling on other molecules. Move materials within a cell, as in transporting molecules and organelles to their destinations; they enable some cells, such as white blood cells, to crawl around in the body's tissues; and they make cells change shape, as when a cell surrounds and engulfs foreign particles or when it divide in two.
- Glycocalyx
- carbohydrate fuzzy surface coating, that acts like an identification tag. Contains glycolipids an glycoprotein. tells difference between healthy cells and transplanted tissues, invading organisms, and diseased cells
- Cell adhesion molecules
- protein membranes that allow cells to adhere to one another and to extracellular material. some do not survive with out this like sperm and egg
- G- Protein
- a protein of the plasma membrane that is activated by a membrane receptor and, in turn, opens an ion channel or activates an intracellular physioloical response; important in linking ligand receptor binding to second- messenger systems
- Adenylate cyclase
- An enzyme of the plasma membrane tha removes two phosphate molecules from ATP and makes cyclic adenosine monophosphate (cAMP); important in the activation of the cAMP second-messenger system.
- Kinases
- in the cytosol,adds phosphate groups to other cellular enzymes. this activates some enzymes and deactivates others.
- Microvilli
- extensions of the plasma membrane that serve primarily to increase a cell's surface area. Good in absorption epithelial cells of the intestines and the kidney
- Cilia
- move substances along cell surface; some sensory roles (hearing, equilibrium, smell, vision)
- axoneme
- the core of microtubules, usually a "9 + 2" array at the center of a cilium of flagellum. the structural basis for ciliary movement.
- basal body
- anchors the cilium
- Dynein
- motor protein invovled in the beating of cilia and flagella and in the movement of molecules and organelles within cells, as in retrograde transport in a nerve fiber
- Flagellum
- whiplike structure much longer than a cilium but still has same axoneme. tail of sperm in humans
- Selectively permeable
- allows some things in membrane like nutrients and wastes, but usually prevents other things such as proteins and phosphates form entering and leaving
- Passive mechanisms
- require no energy expenditure by cell and include filtration and diffusion
- Active mechanisms
- require the cell to consume ATP. include active transport and vesicular transport
- Carrier mediated
- use a membrane protein to transport substances from one side of the membrane to the other
- Filtration
- process in which particles are driven through a selectively permeable membrane by hydrostatic pressure: the force exerted on membrane by water
- Simple Diffusion
- the net movement of particles from a place of high concentration to a place of lower concentration as a result of their constant, spontaneous motion
- Osmosis
- diffusion of water through a selectively permeable membrane from "more watery" to the "less watery" side
- Osmotic pressure
- the amount of pressure that would have to be applied to one side of a selectively permeable membrane to stop osmosis; proportional to the concentration of nonpermeating solutees on that side and therefore serving as an indicator of solute concentration.
- osmole
- 1 mole of dissolved particles
- Osmolality
- is the number of osmoles of solute per kilogram of water
- Osmolarity
- is the number of osmoles per liter of solution
- Tonicity
- is the ability of a solution to affect the fluid volume and pressure in a cell
- Hypotonic
- has a lower concentration of nonpermeating solutes than the intracelllular fluid (ICF). Cells absorb water, swell, and may burst.
- Hypertonic
- solution with a higher concentration of nonpermeating solutes than ICF. fluid (ICF) it causes cells to lose water and shrivel (crenate)
- Isotonic
- the total concentration of nonpermeating solutes is the same as in the ICF--hence they cause no change in cell volume or shape
- Saturation
- as the solute concentration rises, its rate of transport through a membrane increases, but only up to a point. Then levels off at the transport maximum
- Three kinds of carriers
- Uniport, symport, and Antiport
- Uniport
- carries only one solute at a time.
- Symport
- carries two or more solutes through a membrane simultaneously in the same direction (cotransport). Small intestine and kidneys take up sodium and glucose simultaneously
- Antiport
- carries two or more solutes in opposite directions (countertransport)sodium potassium pumps
- Facilitated Diffusion
- carrier mediated transport of solute through a membrane down its concentration gradient. Passive, does not consume DNA. the solute attches to a binding site on the carrier, then the carrier changes conformation and releases the solute on the other side of the membrane
- Active transport
- is the carrier mediated transport of a solute through a membrane up its concentration gradient. Sodium potassium pump
- Vesicular transport
- move large particles, droplets of fluid, or numerous molecules at once through the membrane, contained in bubblelike vesicles of membrane
- endocytosis
- vesicular processes that bring matter into a cell
- exocytosis
- vesicular proccesses that release material from a cell
- Two forms of endocytosis
- phagocytosis and pinocytosis
- Phagocytosis
- cell eating, is the process of engulfing particles such as bacteria, dust, and cellular debis, particles large enough to be seen with a microscope. Occurs in some human cells
- Phagosome
- part of a neutrophil and is a vesicle in the cytoplasm surrounded by a unit membrane.
- Pinocytosis
- cell drinking is the process of takin in droplets of ECF containing molecules of some use to the cell. Occurs in all human cells
- pinocytotic vesicles
- contain droplets of the ECF and ar in the cytoplasm
- Receptor mediated endocytosis
- Phagocytosis or pinocytosis in which specific solute particles bind to receptors on the plasma membrane, and are then taken into the cell in clathrin-coated vesicles with a minimal amount of fluid
- transcytosis
- transport of a substance across a cell
- nucleus
- largest organelle and usually the only one visible with the light microscope. spheroid to elliptical
- anuclear
- no nucleus. RBC
- multinuclear
- having 2-50 nuclei, liver cells, skeletal muscle
- nuclear envelope
- covers the nucleus with nuclear pores on it
- nucleoplasm
- material in the nucleus
- chromatin
- in the nuceleoplasm and is fine thread like matter composed of DNA and protein
- nucleoli
- in the nuceloplasm and there are one or more of these and they are dark staining masses where ribosomes are porduced
- Endoplasmic Reticulum
- an extensive system of interconnected cytoplasmic tubules or channnels; classified as rough ER or smooth ER depending on the presence or absence of ribosomes on its membrane
- Rough Endoplasmic Reticulum
- network is composed of parallel flattened sac covered wtih granules called ribosomes. Protein synthesis and manufatcture of cellular membranes
- smooth Endoplasmic Reticulum
- branching network of tubules with smooth surface usually broken into small segments in TEM photos. Lipid syntesis detoxification calcium storage
- Ribosomes
- small dark granuels free in cytosol or on suface of rough ER. Interpret the genetic code and synthesize polypeptides make them
- Golgi complex
- several closely spaced, parallel cisternae with thick edges, usually near nucleus, often with many GOlgi vesicles nearby. Receives and modifies newly synthesized polypeptides, synthesizes carbohydrates, adds carbohydrates to glycoproteins; packages cell products in to GOlgi vessicles
- golgi vesicles
- round to irregular sacs near golgi complex. Become secretory vesicles and carry cell products to apical surface for exocytosis or become lysosomes
- autophagy
- digesting and disposing of worn out mitochondria and other organelles by the lysosomes
- autolysis
- digestion of surplus cells by their own lysosomal enzymes
- Lysosomes
- package of enzymes bounded by a single unit membrane. Contain enzymes for intracellular digestion, autophagy, programmed cell death, and glucose mobilization
- Peroxisomes
- similar to lysosomes but contain different enzymes and are not produced by the golgi complex. neutralized free radicals and detoxify alcohol and other drugs, and oxidize fatty acids
- Mitochondria
- Synthesize ATP. Round, rod-shaped, bean shaped, or threadlike structures with double unit membrane and shelflike infoldings calle crisate
- matrix
- contains ribosomes, enzymes in ATP synthesis, and small circular DNA molecules. IN space between cristae
- Centriole
- Short cylindrical bodies, each composed of a circle of nie triplets of microtubles. Form mitotic spindle during cell division; unpaired centrioles form basal bodies of cilia and flagella
- Centrosome
- clear area near nucleus containing a pair of centrioles. Organizing center for formation of microtubules of cytoskeleton and mitotic spindle
- Microfillaments
- thin protein filaments (6nm) in diameter, often in parallel bundles or dense networks in cytoplasm. Support microvilli; invovled in muscle contraction and other cell motility, endocytosis and cell division.
- Intermediate filaments
- thicker protein filaments (8-10nm) extending throughout cytoplasm, or concentrated at cell-to cell junctions. give shape a physical support to cell; ancho cells to each other and to extracellular material; compartmentalize cell contents
- Microtubules
- hollow protein cylinders (25nm) form axonemes of cilia and flagella, centrioles, basal bodies, and mitotic spindles; enable motility of cell parts; direct organelles and macromolecules to their destinatino within a cell.
- Inclusion
- Highly variable fat droplets, glycogen granules, protin crytals, dust, bacteria, viruses; never enclosed in unit membranes. Storage products or other products of cellular metabolism, or foreing matter retained in cytoplasm