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75 Cards in this Set
- Front
- Back
Appearance of nucleous on micrograph
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Nuclear envelope continous with RER; euchromatin is white; heterochromatin is dark; central area of nucleolus is light and has DNA not being transcribed; peripheral granular dark area of nucleoulus contains ribosomal precursors in different stages of assembly.
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30nm solenoid chromatin fibers
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Composes heterochromatin and its inactive. Nucleosomes plus H1 molecules
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10nm solenoid chromatin fibers
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Compose euchromatin and its active. Histone octamers (nucleosomes)
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Nucleosome
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Composed of lysine/arginine-rich histone octamers with negatively-charged DNA wrapped around it.
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Nuclear lamina
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In the inner side of the nuclear envelope. Phosphorylation of the lamina disassembles nucleus during prophase.
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Function of the nucleus
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Replication and transcription of DNA. Ribosomal 40S subunit synthesis and assembly.
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Function of the nucleolus
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rRNA synthesis and ribosomal assembly of 60S subunits
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Functions of RER
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Synthesis of proteins destined to be secreted, lysosomes and cell membrane
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Functions of SER
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Detoxification reactions (steroid synthesis, hydroxylation via cytochrome P450, conjugation); Glycogenolysis and gluconeogenesis; Lipid metabolism; sequestration of Ca+.
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Functions of Golgi apparatus
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Posttranslational modifications (acetylation, gamma-carboxylation) Formation of glycoproteins and oligossachride chains (phosphorylation of mannose oligosacchride residues and I-cell disease, insulinase cleaves proinsulin into insulin and C-peptide)
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I-cell disease
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No phosphorylation of mannose residues in oligossacchride chains of glycoproteins fails to direct hydrolases to lysosomes. They are secreted instead. Skeletal abnormalities, coarse facial features, mental retardation.
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Functions of lysosomes
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Contain acid hydrolases for degradation of diverse substances. Hydrolases are assembled in the RER and modified in the GA by phosphorylation of mannose residues.
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Functions of peroxisomes
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Synthesis and degradation of H2O2; Beta oxidation of very long chain fatty acids; Bile acid synthesis.
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Structure of mitochondria
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Outer membrane (permeable); Inner membrane with cristae (impermeable, contain oxidative phosphorylation and electron transport enzymes); Matrix (contain dehydrogenases - pyruvate, fatty acids).
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Function of mitochondria
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Oxidative phosphorylation, electron transport and generation of ATP, beta oxidation, part of the urea cycle and gluconeogenesis
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Functions of microtubules
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Chromosomal movement during meiosis and mitosis; Intracellular organelle transport (kinesin, dynein); cilliary and flagellar movement.
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Chediak-Higashi
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Defect of microtubule polymerization. Prevents phagocytosis (delayed phagosome-lysosome fusion), partial albinism (increased fusion of melanosomes in melanocytes), granule accumulation in NK cells and platelets.
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Functions of microfilaments
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Composed of actin. Local movements (polymerization/depolymerization) and sliding movements via interaction with myosin
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Composition of the basement membrane
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Type IV collagen, glycoproteins (laminin), proteoglycans (heparan sulfate)
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Tight junctions (zonula occludens)
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Fusion of opposed membranes in the apical borders. Seals off the intercellular space. Forms barriers in epithelium.
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Zonula adherens
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Basal to the tight junctions. Attaches adjacent epithelial cells.
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Desmosomes (macula adherens)
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Juxtaposed spot welds that originate within the cytoplasm of two adjacent cells and hold them together.
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Gap junctions
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Tubules that connect and allow pasage of ions between cells.
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What are the apical surface specializations?
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Microvilli, cilia, stereocilia
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Functions of cilia
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Propel fluid and substances in one direction, clear mucus from respiratory tract
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Kartagener syndrome
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Absent or defective dynein arms of cilia. Chronic sinusitis, bronchiectasis, infertility, situs inversus.
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Axon hillock
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Interfase between neuron body and axon where depolarization begins.
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Unmyelinated axons
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In peripheral nerves, surrounded by Schwann cells, small diameter, slow conduction
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Myelinated axons
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Large diameter, fast conduction
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Schwann cells
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Myelinating cells of peripheral nervous system. Myelination begins in the fourth month.
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Oligodendrocytes
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Myelinating cells of CNS. Myelination begins in the 4th month until the 2nd decade of life. Degeneration of oligodendrocytes produces multiple sclerosis and demyelinating diseases.
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Node of Ranvier
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Unmyelinated segment in between myelinated segments of the axon. The action potential skips from node to node.
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Astrocytes
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Maintain the blood-brain barrier
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Microglia
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Derive from mesoderm and are phagocytes of the mononuclear system
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Ependymal cells
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Located in the ventricles, have cilia to move CSF.
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Structure of the sarcomere
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I band with Z line in between; A band with H band in between. H band contains thick myosin filaments. I band contains thin actin filaments. A band contains thick and thin filaments. H and I bands shorten during contraction.
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Actin
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Double helix component of thin filaments, has myosin crossbridges binding sites
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Tropomyosin
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Double helix component of thin filaments that run on actin filaments covering the myosin binding sites
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Troponins
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TnT binds tropomyosin; TnC binds calcium; TnI inhibits actin-myosin interaction. When calcium binds TnC, the troponin-tropomyosin complex moves and uncovers the actin binding sites for myosin crossbridges.
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Myosin
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Component of the thick filaments. Has a head and two tails. The head has ATPase activity and actin-binding sites to form crossbridges.
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Lymph node cortex
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B cells, follicles and germinal centers
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Lymph node paracortex
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Populated by T cells
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Spleen white pulp
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Surrounds arteries. Periarteriolar sheaths contain T cells and peripheral white pulp contains B cells and germinal centers.
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Spleen red pulp
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Is beyond the periarteriolar sheaths and contains macrophages that extract damaged erythrocytes from blood.
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Layers of epidermis
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Basale (columnar cells), spinosum (cuboidal), granulosum (flat), lucidum (flat anucleated), corneum (flat kertinized)
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Keratinocytes
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Produce keratin and have desmosomes. In pemphigus there are autoantibodies against keratinocyte desmosomes.
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Melanocytes
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Neural crest ectoderm derivatives. In dermis and epidermis produce melanin melanosomes.
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Langerhans cells
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Dendritic antigen presenting cells.
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Merkel cells
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Sensory cells with cathecolamine granules.
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Pemphigus
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Autoantibodies against keratinocyte desmosomes. Superficial blisters.
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Psoriasis
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Hyperplasia of basale and spinosum layers with increased turnonver and thickness. Produces descamation.
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Albinism
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Melanocytes won't produce melanin due to lack of tyrosinase. Increased risk of SCC and melanomas.
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Vitiligo
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Autoantibodies against melanocytes produce depigmentation
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Bullous pemphigoid
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Autoantibodies against hemidesmosomes in dermis/epidermis junction. Blisters and separation of dermis from epidermis.
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Dermis
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Derived from mesoderm. Supplies blood to epidermis and contains appendages.
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Eccrine sweat glands
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Most body parts, watery discharge, cholinergic innervation.
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Apocrine sweat glands
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Axila, areola and anal regions. Adrenergic innervation.
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Sebaceous glands
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Associated with hair follicles. Produce lubrication for hair and skin.
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Cells of the respiratory nasal cavities
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Pseudostratified, ciliated, columnar with goblet cells, mucous and serous glands. The conchae increase surface area, warms up the air and is richly vascularized and innervated.
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Cells of the olfactory nasal cavities
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In the posterosuperior nasal cavity, has pseudostratified bipolar neuron which can divide. Bowman glands produces serous fluids that dissolve odorous substances
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Paranasal sinuses
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Frontal, maxillary (2), sphenoid and ethmoid
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Type I pneumocytes
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Line the alveoli lumen and constitutes the main cell of the blood-air interface
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Type II pneumocytes
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Cuboidal cells that sit on the basal lamina and produce surfactant to reduce alveolar surface tension.
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Alveolar macrophages
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On the surface of alveoli. Phagocytosis of foreign particles.
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Esophagus histology
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Nonkeratinized stratified squamous epithelium. Skeletal muscle in upper 1/3, smooth muscle in lower 1/3.
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Barret's esophagus
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Squamous-columnar metaplasia at gastro-esophageal junction due to acid-reflux disease
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Cells of body and fundus of stomach
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Mucous cells (secrete mucous, tight junctions); Chief cells (pepsinogen, lipase); Parietal cells (IF, HCl)
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Cells of the pylorus
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Mucous cells (mucous and tight junctions); Parietal cells.
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Characteristics of duodenum
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Brunner glands secrete alkaline secretions; Goblet cells secrete acid glycoproteins that protect mucosa; Paneth cells; EE cells secrete CCK and secretin.
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Characteristics of jejunum
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Brunner glands secrete alkaline secretions; Goblet cells secrete acid glycoproteins that protect mucosa; Paneth cells; EE cells secrete CCK and secretin.
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Characteristics of ileum
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Peyer patches are lymph aggregations; M cells endocytose antigen from lumen to lymphoid cells.
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Layers of the digestive tract
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From the lumen out: mucosa, muscularis mucosa, submucosa, muscularis externa, serosa
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Parotid gland
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Serous acinars secrete amylase. Innervated by IX
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Visceral layer of Bowman's capsule
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Podocytes rest on basal lamina which is shared with the fenestrated capillary endothelium.
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Parietal layer of Bowman's capsule
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Simple squamous epithelium continous with proximal tubule epithelium.
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