Chapter 3 & 4 Flashcards
Forms a selectively permeable barrier between the nuclear and cytoplasmic compartments
Nuclear envelope
It is the command center of the cell also contains the molecular Machinery to replicate the DNA and to synthesize and process all types of RNA
Nucleus
A narrow space that separates the two concentric membranes of the nuclear envelope
Perinuclear space
And organized meshwork of proteins which stabilizes the nuclear envelope
Nuclear lamina
Class of intermediate filament proteins that bind to the membrane proteins and associate with chromatin and non-dividing cells
Lamins
Inner and outer nuclear membranes are bridged at this
Nuclear pore complexes
Various core proteins of a nuclear pore complex
Nucleoporins
A sex chromatin
Barr Body
A basic protein that extensively packages DNA and chromatin
Histones
Hey structural units of DNA and histone which has a core of eight histones
(2 copies each of histones H2A H2B H3 and H4) around which is wrapped DNA with about 150 base pairs
Nuclesome
Each long DNA double helix with it’s associated proteins
Chromatid
Two chromatids held together by complexes of cohesion proteins
Chromosome
Barr bodies or gender chromatin permit gender to be determined microscopically in patients whose external sex organs do not permit as in ______________ & _______________
Hermaphroditism , pseudohermaphroditism
The presence of XXY chromosomes __________________ which causes testicular abnormalities and __________ ( absence of sperm)
Klinefelter syndrome, azoospermia
Contains pairs of chromosomes
Diploid
Although from different parents they contain forms ( alleles) of the same genes
Homologous
Stained chromosomal regions ( bands) that can be analyzed
Karyotypes
___________Is important for many prenatal diagnosis in which home is on analysis of cultured cells from the fetus or Amnion can detect certain genetic anomalies. as with karyotypes of adults, missing or extra chromosomes chromosome deletions or translocations are readily seen
Karyotyping
A spherical highly basophilic subdomain of nuclei in cells, actively making proteins
Nucleolus
Is the sequence of events that controls cell growth and division
Cell cycle
Is the longest part of the cycle begins immediately after mitosis and includes all preparations for DNA replication
G1 Phase
The period of DNA and histone syntheses
S Phase
A short phase where the cell prepares for division during mitosis
G2 Phase
Cell cycling is controlled by the sequential appearance of Cytoplasmic proteins the _________ which bind ______________
Cycling, cyclin-dependent kinases (CDKs)
Phosphorylate and activate the enzymes and transcription factors whose functions characterize each phase of the cell cycle
CDKs
When cell cycle activities may be temporarily or permanently suspended the cells are referred to as being in the ______ space
G0
The stages of mitosis
Prophase, metaphase, anaphase, telophase,cytokinesis
Occur in all tissues with rapid cell turnover they divide slowly in a asymmetric manner with one daughter cell remaining a stem cell and becoming committed toward differentiation
Stem cells
Cells committed to differentiate typically divide more rapidly than stem cells before slowing stopping division to differentiate
Transit amplifying or progenitor cells
Is the process by which two successive cells divisions produce cells gametes containing half the number of chromosomes found in somatic cells
Meiosis
Prophase of the fist meiotic division is a unique, extended period in which homologous chromosomes pair and undergo genetic recombination during the process called ______
Synapsis
Is the process by which redundant or defective cells are rapidly eliminated in a manner that does not provoke a local inflammatory reaction in the tissue
Apoptosis
Apoptosis involves a cascade of events controlled by the _______ family of proteins regulating the release of death-promoting factors from mitochondria
Bcl-2
Cytochrome c from mitochondria activates cytoplasmic Proteases called __________ which degrade proteins of the cytosol, cytoskeleton and cell membrane
Capases
Degrade all nuclear DNA
Endonucleases
Late In apoptosis the cell into many small _____________ that undergo ______________ by neighboring cells
Apoptotic bodies, phagocytosis
___________ typically follows damage to the DNA of proto-oncogenes and failure of the cells to be eliminated ________ growth can either be benign or malignant ( commonly called cancer)
Neoplastic proliferation, neoplastic
Certain mutants in the gene __________ are associated with a subtype of the disorder progeria which causes ______________ in this and other rare laminopathies the nuclear envelope is abnormal
Lamin A, premature aging
Many mitogenic growth factors for research are produced commercially from microorganisms or cells with recombinant DNA have important med uses ex. Include analogs of _________________
granulocyte colony-stimulating factor (G-CSF)
Many genes coding proteins important in the control of cell proliferation and differentiation are often called ________________
Proto-oncogenes
Changing in the structure or expressing of these can convert them to _____________ causing uncontrolled cell and a potential for cancer
Oncogenes
A type of cancer occurring in the eyes, usually in young children one form of the disease is inherited or familial. Lead to the discovery of the gene Rb, which blocks the cell cycle progression until a mitogenic stimulus arrives
Retinoblastoma
The active cyclin-CDK complex which occurs in the early G1 phase
Cyclin D-CDK4 or 6
The active cyclin-CDK complex which occurs in the late G1/ entry of S phase
Cyclin E-CDK2
The active cyclin-CDK complex which occurs in the progression through the S phase
Cyclin A-CDK2
The active cyclin-CDK complex which occurs in the G2 entry of M Phase
Cyclin A-CDK1
The active cyclin-CDK complex which occurs in the progression through the M Phase
Cyclin B-CDK1
Examples of target cells if Cyclin D-CDK4 or 6 are
Phosphorylates Rb protein, releasing E2F a transcription factor that activates genes for many G1 activities and for cyclin A
Examples of target cells if Cyclin E-CDK2
Further activation E2F mediated gene transcription; protein p53; other kinases
Examples of target cells if Cyclin A-CDK2
DNA polymerase and other proteins for DNA replication
Examples of target cells if Cyclin A-CDK1
Specific phosphatases and cyclin B
Examples of target cells if Cyclin B-CDK1
Nuclear lamins; histone H1; chromatin and centrosome associated proteins
Down syndrome is associated with morphologic and cognitive impairments of the _______ chromosome
21
_________ cells often deactivate the genes that control the Apoptotic process , thus preventing their elimination in this type of cell death and allowing progression toward a more malignant state
Cancer
Nuclei of cells in __________ ____________ are often enlarged, abnormally shaped, and extremely dark staining
Malignant tumors
Is a tissue in which cells are bound tightly together structurally and functionally to form a sheetlike or tubular structure with little extra cellular material between the cells
Epithelium
Facing the sheet’s free surface
Apical side
Facing a basement membrane and under-lying connective tissue
Basal side
Epithelial are often specialized for absorption or ___________, pinicyctosis of material at the apical and exocyctosis at the basolateral side ( or vice versa)
Transcytosis
Most epithelial exhibit ___________ ___________ with the locations of stem cells and rates of cell turnover variable in various specialized epithelia
Continuous renewal
The extra cellular layer of specialized proteins, usually having 2 parts: a basal lamina and more fibrous reticular lamina
Basement membrane
A thin mesh work of type IV collagen and laminin produced by the epithelial cells
Basal lamina
Contains type III collagen and anchoring fibrils of VII collagen, all secreted by cells of the immediately adjacent connective tissue
Reticular lamina
Are formed by interacting transmembrane proteins such as claudin and occludin; linear arrangements of those linked proteins surround the apical ends of the cells and prevent para cellular passage of substances
Tight or occluding junctions
Formed by interacting proteins of the cadherin family, are points of strong attachment holding together cells of the epithelium
Adherent or Anchoring junctions
Adherent junctions may form ___________ that encircle epithelial cells just below their tight junctions or scattered
Zonula adherens
Scattered Spot like attachment sites
Desmosomes or maculae adherens
Composed of transmembrane integrins attach cells to proteins of the basal lamina
Hemidesmosomes
Points of cell contact where both plasma membranes have numerous hexameric complexes of transmembrane connexons each forming a channel allowing passage of small molecules from one cell to the other
Gap or communicating junctions
A hexameric complex of transmembrane protein which has a central hydrophilic pore about 1.5 nm in diameter
Connexon
Small membrane projections with core of actin filaments that generally function to increase epithelial cell’s apical surface area of absorption
Microvilli
Long microvilli with specialized mechanosensory function in cells of the inner ear and for absorption in tissues of the male reproductive tract
Stereocilia
Are larger projecting structures with well organized core of microtubules ( 9+2 arrangement) in which restricted, dynein based sliding of microtubules causes ciliary movement that propel material along an epithelial surface
Cilia
Microtubules in an 9+2 arrangement
Axoneme
A epithelium in which the basement membrane has one cell layer
Simple
epithelium that are very thin
Squamous
Epithelium where cell width and and thickness are roughly similar
Cuboidal
Epithelium where cells are taller than they are wide
Columnar
Cells of stratified squamous epithelia move gradually from the basal to the surface layers, changing shape and becoming filled with ______ intermediate filaments
Keratin
Epithelia with two or more layers
Stratified
Stratified epithelia in which the outer cell layers are thin and flat
Stratified squamous
Stratified squamous epithelia such as the epidermis cover the body surface, ________ underlying tissues from excess water loss ( dehydration) and microbial invasion
Protecting
Are thick and appear to have several cell layers; all cells attach to the basal lamina but not all extend to the free epithelial surface
Pseudostratified epithelia
Found only in the lining of the urinary system, is stratified, with large rounded surface cells protective against urine
Transitional epithelium or urothelium
The major function in many epithelial cells is synthesis and secretion of specialized products; organs composed primarily of such epithelia are called___________
Glands
Have epithelial ducts carrying secretions and specific sites also retain their connection with the surface epithelium ( have ducts)
Exocrine glands
Lack ducts; secreted substances are hormones carried throughout the body by the interstitial fluid and blood, with specificity produced by the hormone receptors of target cells (lose connection to their original epithelium)
Endocrine glands
Glands have 3 secretory mechanisms
Merocrine, Holocrine, apocrine
Secretory mechanism that uses exocyctosis
Merocrine
Secretory mechanism in which terminally differentiated cells filled with lipid product are released
Holocrine
Secretory mechanism in which apical, filled areas of cells are extruded
Apocrine
A unicellular gland found in the lining of the small intestine and respiratory tract, which secretes lubricating mucus that aids the function of these organs
Goblet cells
Oligosaccharides components of mucus stain poorly with routine dyes but stain well with________ stain
PAS
Glands with ducts that are not branched
Simple ducts
Glands with ducts that are branched
Compound glands
Secretory portions of glands that are either short or long and coiled
Tubular
Secretory portions of glands that are rounded or saclike
Acinar
Located inside the basal lamina around the basal ends of secretory or duct cells long processes of these cells embrace an acinus as an octopus might embrace a boulder are rich in actin and myosin ( their contractions serve to help propel secretory into and up the duct system)
Myoepithelial
________ __________ common among habitual smokers is where the number of goblet cells in the lining of airways in
The lungs often increases greatly, which leads to excessive mucus production in areas with few ciliated cells
Chronic bronchitis
Malignant tumors of epithelial origin
Carcinomas
Malignant tumors derived from glandular epithelial tissue ( most common in adults after age 45)
Adenocarcinomas
A precancerous growth
Neoplasia
Under abnormal conditions, one type of epithelial tissue may undergo transformation into another type in another reversible process
Metaplasia
Individuals with _______ ________ ___ deficiency, epithelial tissues of the type found in the bronchi and urinary bladder are gradually replaced by stratified squamous epithelium
Chronic Vitamin A
Exocrine glands producing largely enzymes ( proteins) are called ( stain darkly with H&E due to cell’s content of RER and secretory granules
Serous glands