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Anatomy - Ch. 2
Anatomy - Chapter 2 - Cytology
Question | Answer |
---|---|
Cytology | is the scientific study of cellular structure and function |
True or False; cellular function = METABOLISM | True |
True or False; cells aren't important from a clinical perspective because many body dysfunctions and diseases do NOT originate at the cellular level. | False |
The basis of disease is what? | breakdown in the proper functioning of cells (whether caused by microorganisms, inherited defects or by injury) |
True or False; Aging occurs at the cellular level? | True |
Cell Theory key points | Every living organism is made of cells Cells arise only through the division of pre-existing cells rather than springing spontaneously from nonliving matter All cells have the same basic chemical components |
Simple Squamous cell description | thin, flat, scaly shape |
line esophagus and form surface layer of skin | simple squamous |
Simple Cuboidal cell description | squarish, about equal in height and width |
liver cells | simple cuboidal cells |
Simple Columnar cell description | distinctly taller than wide |
inner lining of intestines | Simple Columnar cells |
Polygonal cells descriptions | irregular angular shapes with four or more sides |
Stellate cells descriptions | multiple pointed processes give cells a somewhat starlike shape |
cell bodies of nerve cells | Stellate cells |
Spheroid to ovoid cells descriptions | round to oval |
egg cells and white blood cells | Spheroid to ovoid |
Discoid cells descriptions | disc-shaped, as in red blood cells |
Fusiform cells descriptions | spindle-shaped; elongated, with a thick middle and tapered ends |
smooth muscle cells | Fusiform cells |
Fibrous cells descriptions | long, slender, and threadlike |
skeletal muscle cells and the axons (nerve fibers) of nerve cells | Fibrous cells |
Plasma membrane (cell membrane) | forms the surface boundary of the cell |
cytoplasm | Material between plasma membrane and nucleus |
nucleoplasm | Material within the nucleus |
Functions of Membrane Proteins: Receptor | Binds to chemical messengers such as hormones sent by other cells |
Functions of Membrane Proteins: Enzyme | Breaks down a chemical messenger and terminates its effect on the target cell. |
Functions of Membrane Proteins: Channel protein | A channel that is constantly open and allows solutes to pass into and out of the cell |
Functions of Membrane Proteins: Gated channel | A gated channel that opens and closes to allow solutes through only at certain times |
Functions of Membrane Proteins: Cell-identity marker | A glycoprotein acting as a cell-identity marker distingushing the body's own cells from foreign cells. |
Functions of Membrane Proteins: Cell-adhesion molecule (CAM) | A (CAM) that binds one cell to another |
Microvilli | Plasma membrane extension; Increase surface area; Brush border |
Cilia | Primary cilium; Motile cilia; Axoneme – microtubules; Dynein – motor protein; |
Flagella | Long, singular cilium; Sperm cell |
Surface extensions: Microvilli | best developed on cells that specialize in absorption (i.e., intestines) function to increase the surface are of cells 15-40 times more absorptive surface area |
Surface extensions: Cilia | hair-like processes that extend from cells some sensory (inner ear) others function to move things (respiratory tract, uterine tubes) |
Surface extensions: Flagella | longer and fewer (only 1 or 2 per cell) only human cell to have one is the male sex cell or sperm - locomotive structure |
At the cell surface are certain arrangements of proteins called... | intercellular junctions |
intercellular junctions | Link cells together and attach them to the extracellular material |
3 types of intercellular junctions | 1) tight junctions 2) desmosomes 3) gap junctions |
Tight Junctions | Join it tightly to the neighboring cells Zipperlike Seals off intercellular space and makes it difficult for substances to pass between cells |
Desmosomes | A patch that holds cells together. More like a snap than a zipper. Not continuous. Resists mechanical stress. |
Gap (Communicating) Junctions | A gap junction is ringlike and surrounds a water-filled channel Fluids can diffuse through the channel directly from the cytoplasm of one cell into the next |
intracellular fluid (ICF) | fluid within the cell (the cytosol) |
All body fluids not contained in the cells are collectively called.. | extracellular fluid (ECF) or tissue (interstitial) fluid |
Blood plasma, lymph, and cerebrospinal fluid are examples of what? | extracellular fluid (ECF) |
Structures in the cytoplasm are classified into three groups: | Cytoskeleton, Inclusions, Organelles; Embedded in a clear gel: the cytosol |
Cytoskeleton | a supportive framework of protein filaments and tubules |
Inclusions | non metabolically active parts of the cell stored cell products such as lipids and pigments foreign bodies such as dust and bacteria |
The Nucleus: Description | Round; Near center of cell; Largest organelle; Nucleoplasm (cytoplasm equivalent); |
Organelles | The minute, metabolically active structures within a cell are called organelles (literally “little organs”) because they are to the cell what organs are to the body—structures that play individual roles in the survival of the whole |
Ribosomes | small granules of protein and ribonucleic acid (RNA); Synthesize proteins |
Endoplasmic Reticulum | a system of interconnected flattened membrane |
rough endoplasmic reticulum | covered with ribosomes |
smooth endoplasmic reticulum | no ribosomes |
Endoplasmic Reticulum; Action | synthesizes steroids and other lipids, detoxifies alcohol and other drugs, and manufactures all of the membranes of the cell |
Golgi Complex | Stack of flattened membranous sacs |
Golgi Complex; Action | Synthesize carbohydrates |
Lysosome | a package of enzymes contained in a single unit membrane. (apoptosis) |
apoptosis | “cell suicide” in which cells that are no longer needed undergo a prearranged death |
Mitochondria | are organelles specialized for ATP synthesis; Sac-like; Powerhouse of the cell |
centriole | a bundle of microtubules |
centrosome | a small, clear patch of cytoplasm that contain a pair of mutually perpendicular centrioles; These centrioles play a role in cell division |
This cell cycle is divided into four main phases | G1,S,G2,and M |
The Cell Cycle – The first gap (G1) phase | a cell synthesizes proteins, grows, and carries out its preordained tasks for the body |
The Cell Cycle – synthesis (S) phase | a cell carries out DNA replication |
A cell begins the __ phase with 46 molecules of DNA and ends this phase with 92 The cell then has two identical sets of DNA molecules, which are available to be divided up between daughter cells at the next cell division | synthesis (S) phase |
The Cell Cycle - second gap (G2) phase | a cell finishes replicating its centrioles and synthesizes enzymes that control cell division |
The Cell Cycle – mitotic (M) phase | the period in which a cell replicates its nucleus, divides its DNA into two identical sets |
Interphase | Phases G1, S, and G2 are collectively called interphase — the time between M phases |
Mitosis | cells divide by two mechanisms |
Meiosis | only sex cells |
Mitosis; Farther functions | the development of an individual continued growth of all the organs after birth the replacement of cells that die the repair of damaged tissues |
Four phases of mitosis are recognizable as | prophase, metaphase, anaphase, and telophase |
Prophase | Chromatin condenses. Nucleoli and nuclear envelope break down. Spindle fibers grow from centrioles. Centrioles migrate to opposite poles of cell |
Metaphase | Chromosomes lie along midline of cell. Some spindle fibers attach to kinetochores. Fibers of aster attach to plasma membrane. |
Anaphase | Centromeres divide in two. Spindle fibers pull sister chromatids to opposite poles of cell. Each pole now has an identical set of genes. |
Telophase | Chromosomes gather at each pole of cell. Chromatin decondenses. New nuclear envelope appears at each pole. Mitotic spindle vanishes. |
Cytokinesis | division of the cytoplasm |
cleavage furrow | a crease around the equator of the cell, and the cell eventually pinches in two |
Stem Cells | mmature cells with the ability to develop into one or more types of mature, specialized cells |
Adult stem (AS) cells | multiply and replace older cells that are lost to damage or normal cellular turnover |
Embryonic stem (ES) cells | comprise human embryos of up to 150 cells |