HHP Review Flashcards
What do lipid rafts contain high concentrations of?
Cholesterol, glycosphingolipids, membrane associated proteins
How do bacteria and viruses take entry into cell through lipid rafts?
They hijack lipid rafts with their signaling mechanism
What are two types of lipid rafts?
Planar-Flotillin proteins
Caveolar- Caveolin proteins
What does flotillin/planar lipid raft function in?
Signaling pathways, recruitment of specific membrane proteins into rafts
What does caveolin lipid raft function in?
Invagination of plasma membrane initiates vesicle formation
What is actin attached to laminin by?
Integrin linker protein
What is role of cholesterol in membrane fluidity?
Prevents tight packing of saturated fatty acids therefore preventing membrane freezing in cold temperature
Structural buffer for unsaturated fatty acids therefore limits excessive fluidity in warm temperatures
Is macropinocytosis actin or clathrin dependent?
Actin dependent, clathrin independent
Is phagocytosis actin or clathrin dependent?
Actin dependent, clathrin independent
Is receptor mediated endocytosis actin or clathrin dependent?
Clathrin dependent
When does clathrin coated vesicles take place?
Receptor mediated endocytosis
Vesicle movement from golgi to endosomes
Trans face
When does coatomer coated vesicles take place?
Anterograde transport- vesicles move from rER to golgi, coated with COPII
Retrograde transport- vesicles move from golgi to rER, coated with COPI
When does caveolin coated vesicles take place?
Smooth muscle, endothelial cells
What do microvilli contain at core?
Where are they found?
Actin filaments
Absorptive cells; intestine, gall bladder, kidney tubules
What do cilia contain at core?
Where are they found?
Microtubules
Respiratory tract, oviduct
Where are basolateral folds found?
Absorptive cells; intestine, kidney tubules
Where is cytochrome C enzyme found?
Mitochondria
What is the importance of sarcoplasmic reticulum in striated muscle fibers?
Storage of calcium, trigger contraction of myofibrils
What is proteasome mediated protein degradation tagged by?
Ubiquitin, used by cells to destroy abnormal proteins
What does malfunction of proteasome mediated degradation lead to?
Decreased protein degradation- Alzhiemers disease, angleman syndrome
Overexpression, accelerated degradation of proteins -infection with HPV
What is lysosomal storage disease?
Absence of certain lysosomal enzymes, due to mutations in a gene that encodes lysosomal proteins
Tay-Sachs disease
Gauchers disease
Pompes disease
Neimann-Pick disease
What do peroxisomes regulate?
Hydrogen peroxides levels in cells, uses catalase enzymes
In sER
What does malfunction of peroxisome lead to?
Zellwger syndrome
Hypotonia, liver jaundice, polycystic kidney disease
What is karyokinesis?
Division of nucleus
What is cytokinesis?
Division of cytoplasm
What is importance of G0 phase?
Some cell types are quiescent, enter G0 and perform its function without actively preparing to divide, ex. Neuroblast
Other cells may restart division if they get right signal
Stem cells hang out here
What does p53 do for G1/S checkpoint?
If it senses DNA damage, it halts progression of cell cycle by blocking Cdk2 activity until damage is repaired
What does p53 do for G2/M checkpoint?
In case of damage to DNA after S phase, it halts cycle and inhibits action of Cdk1, stopping progression of cell from G2 to mitosis
Cdk cannot work without cyclins
True, only the cyclin CDK complex is an active kinase
What happens if p53 is not intact?
Abnormal/malignant cells are formed
What does G1 cyclin, cyclin D interact with?
CDK4 and CDK6
What does G1/S cyclins, cyclin E interact with?
CDK2, starts the system called START-triggers the G1/S phase transition, at this point cells are irreversibly committed to cell division
Further activates E2F mediated gene transcription, p53 and other kinases
What does S phase cyclins, cyclin A and E interact with?
Binds to CDK2 and are responsible for DNA synthesis
What does mitotic cyclins, B cyclins interact with?
CDK1, promotes progression though mitosis
Mitotic cyclin CDK complexes are synthesizes during S phase and G2, but activities are held in check until DNA synthesis is completed (B cyclin forms in previous phase, but becomes active in M phase)
Need laminin in nucleus to function properly, Histone H1 protein
What is the most important regulatory control that restricts cyclins to the appropriate cell cycle stage?
Ubiquitin-mediated protein degradation
Removes cyclin and CDK, they only function once during phase, new cyclin and CDK are used for every phase
CDKs play a important role in cell cycle regulation by?
Control cell division and modulate transcription in response to several extra and intracellular cues
Cyclin CDK complex provide a phosphate group to a number of proteins that control processes in cell cycle, activity can be further modulated by?
Phosphorylation and other binding proteins like p27
What is process of Rb protein and apoptosis?
Rb is tumor suppressor protein, it inhibits apoptosis
Phosphorylation of Rb protein releases E2F transcription factor that inhibits Rb gene, so apoptosis operates well
E2F also activates genes for many G1 activities and for cyclin A
What enzyme does sER need for detocxification?
Cytochrome P450
What is the fibrillae center/nucleolar organizer?
Contains different chromosomes that have the rRNA genes
What is the dense fibrillar component/pars fibrosa?
Contains ribosomal genes actively undergoing transcription, RNA coding happens here
What is the granular component/pars granulosa?
Site of initial ribosome assembly, small or large, then sent to cytoplasm and form complete ribosome
What is the nuclear pore complex?
Mediates transport of cellular material between nucleus and cytoplasm
What happens when nuclear lamin structure is impaired?
Can cause tissue specific diseases like nerve and skeletal muscle development, premature aging
What disease happens when there is mutation to lamin or lamin receptors?
Development of Emery-Dreifuss muscular dystrophy
What does a protein use to get into nucleus through nuclear pore complex?
Importin or lmp
What does a ribosomal subunit use to leave the nucleus through nuclear pore complex?
Exportin or exp
What are some cell loss disorders?
AIDS
Alzheimers
Parkinsons
Aplastic anemia
Myocardial infarction
What are some cell accumulation disorders?
Cancer
Lupus
Glomerulonephritis
Viral infections
What are characteristics of necrosis?
Rapid cell swelling and lysis, pro inflammatory
What are characteristics of apoptosis?
Nuclear DNA fragments, cytoskeleton destroyed, no spillage of contents
What is karyolysis?
Basophilia of chromatin fades due to loss of DNA by endonucleases
What is pyknosis?
Irreversible chromatin condensation, shrinking nuclei
What is karyorrhexis?
Fragmentation of the nucleus, disappears in 1 to 2 days
What do mitochondria release in apoptosis?
Cytochrome C and SMAC/DIABLO into cytoplasm, caspase activation is triggered
What is SMAC/DIABLO?
Second mitochondria derived activator of caspases/ direct inhibitor of apoptosis binding protein with low isoelectric point
What does cytochrome C activate?
Initiates initiator caspases, which activate executioner caspases, activates endonucleases which fragment DNA and destroy cytoskeleton
What are endonucleases activation dependent on?
Ca2+ and Mg2+
What is membrane blebbing in apoptosis?
Molecules like phosphatidylserine are moved from P face to E face, this signals all phagocytic cells to come and remove cell blebbing
What is intrinsic pathway of apoptosis?
Loss of nutrients, oncogenes, tumor suppressor p53 (p53 makes mitochondria discharge cytochrome C and SMAC/DIABLO)
What is extrinsic pathway of apoptosis?
Free radicals, oxidants, UV or ionizing radiation, cytokines (TGF-B), ligation of FAS, release of granzymes from cytotoxin T cells or NK cells can trigger apoptosis
What is most important regulator of apoptosis?
Bcl-2 family of proteins
What does Bcl-2 proteins consist of?
BAX-pro apoptitic Bcl2 protein, can activate and deactivate aopotosis
Regulate release of death promoting factors from mitochondria
p53 activates BAX which allows cytochrome C into cytoplasm
What is anoikis?
Apoptotic process that occurs in cells in response to loss of adhesion to ECM
Thought to involve signaling through integrins attached to ECM
What can go wrong if cells develop mechanisms to survive anoikis?
Metastatic cancers
What is paraptosis?
Cell death mediated by kinases, NOT caspases, can be induced in response to growth factor receptors
What is pyroptosis?
Inflammation induced death involving caspase 1
What is necroptosis?
Caspase independent cell death via FAS
What is DNA made of?
Eight histone proteins, H1 histone, wrapped into spiral called solenoid
What is heterochromatin?
Densely packed and looks dark and granular, DNA that is not being actively transcribed
What is euchromatin?
Looks clear or light, stretched out so gene transcription can take place, prominent in active cells like liver cells
What can a barr body in a neutrophil be used to identify?
Female genetic sex
Where is primary site of ribosomal production?
Nucleolus
What is lamin?
Protein of any class of fibrous proteins that provide structure and regulate transcription in a cell nucleus
What is laminin?
Any class of glycoproteins found in basement membranes
What is the interphase nucleus?
A nucleus of a non dividing cell
What is importance of uroplankin?
Protein makes the epithelium impermeable to water and toxic substances in urine
How is E coli able to attach to uroplankin and leads to UTI?
Penetrate into epithelium and attach to uroplankin
What is basement membrane made of?
Type 4 collagen, laminin, proteoglycans like nidogen and perlecan
What do integrins on basal surface of epithelial cells interact with?
Proteins on basement membrane
Why are laminins important?
Attach to integrins which attaches actin to basal lamina, important because it provides mechanical support and strength
What is basal lamina attached to underlying reticular fibers/reticular lamina by?
Anchoring fibrils which are type 7 collagen
Makes epithelium more stable
What is dystrophic epidermolysis bullosa?
Inherited blistering skin disease, occurs due to mutations of type 7 collagen gene
What do fibrillin microfibrils do?
Attach lamina densa to elastic fibers
What does mutation to fibrillin gene cause?
Marfan syndrome
What do projections of lamina densa do?
Interact with reticular lamina, an additional binding site with type 3 collagen
Reticular fibers are what type of collagen?
Type 3
What does mucosa consist of?
Basal lamina and epithelium
What does serosa consist of?
Mesothelium, basal lamina, and underlying connective tissue
What does microvilli contain at core?
Bundles of actin filaments, held together by crosslinking proteins Villin and fimbrin
What links actin filaments in microvilli to the plasma membrane?
Myosin 1 and calmodulin
What does the terminal web of the apical cytoplasm contain?
Actin, spectrin, Myosin II
What does contractile Myosin II do for microvilli?
Results in decreasing diameter of apex of intestinal absorptive cells, thereby the microvilli spread apart and the intermicrovillar space increases
Where can stereocilia be found?
Epididymis, Ductus deferens
What is internal filamentous structure of stereocilia?
Actin
What does cilia contain?
Microtubules, also called Axoneme, that are derived from centriole, basal body is a microtubule organizing center
What are microtubules made of?
Tubulin subunits
What is arrangement of cilia?
9+2 arrangement, peripheral microtubules are made of alpha and beta tubulin subunits (attached by Nexin)
Each doublet of cilia exhibits a pair of arms containing what?
Dyenin and ATPase
What does hydrolysis of ATP produce in cilia?
Sliding movement along the crossbridge between A microtubule and B microtubule of adjacent doublet, as a result the cilium beats
What is primary ciliary dyskinesia/Immotile cilia syndrome?
Autosomal recessive disease, abnormal ciliary motion and impaired muco-ciliary clearance, leading to persistent or recurrent respiratory injections, male infertility, sinusitis, otitis media
What is Kartagener syndrome?
When dyenin arms are absent in the cilia, leads to abnormal ciliary function, characterized by triad of situs inversus, chronic sinusitis, and bronchiectasis
What is primary cilia?
9+0 microtubule arrangement, non motile, bend by flow of fluid, function as signal receptors
What is nodal cilia?
9+0 microtubule arrangement, concentrated in area of primitive node, found in bilaminar embryonic disc, make rotational movements
What are basal folds usually oriented with?
Lots of mitochondria, provide energy for active transport
What do the basal folds and mitochondria together show?
Striated appearance
What transmembrane proteins are used in tight junction sealing?
Occludins, Claudins
Form a zipper seal
The cytoplasmic portion of occludin and claudin attach with signaling proteins known as zonula occludens proteins ZO-1,ZO-2, ZO-3, what do they do?
ZO proteins interact with cytoskeleton actin filaments
What are ZO-1 and ZO-2 proteins vulnerable to?
Toxins and pathogenic viruses
What causes happen to occluding junctions by toxins and pathogenic viruses?
Cause junctions to become permeable
What does H pylori do to occluding junctions?
Damages occluding junctions of the gastric mucosa, causes leakage of HCl into walls of stomach, leads to bleeding and peptic ulcers
What do occluding junctions do for blood brain barrier?
Prevents proteins in the circulating blood entering the nerve tissue
Chemotherapy cannot be used to treat brain tumors due to BBB
What is zonula adherens?
Continuous band like adhesion, surrounds cell and joins it to neighboring cell
What is desmosome or macula adherens?
Spot adhesion, does not go all the way around cell, located at sites on lateral surfaces of adjoining cells
What transmembrane protein does zonula adherens use?
E-cadherin, known to be tumor suppressor
Cytoplasmic domain of E cadherins bind with what?
Catenin, catenin binds with vinculin, vinculin binds with actin filaments
What does integrity of zonula adherens depend on?
Calcium, removal of calcium disrupts this junction, makes transmembrane proteins weak
What proteins associate with desmosomes?
Desmogleins, desmocollins
Provide strong attachment to cell
Cytoplasmic ends of proteins desmogleins and desmocollins bind with what?
Plakoglobins, plakoglobins bind with desmoplankins, desmoplankins bind with intermediate filaments or keratin filaments
Keratin filaments form cable like filaments called Tonofilaments
What transmembrane does Gap junction associate with?
Connexons, each connexon is made up of 6 connexin proteins
What do connexons do for gap junctions?
Precisely align cell membrane connexons with another cells corresponding connexons, tightly packed connexons create gap junctional plaque that provides communication between cells and exchange of ions
What are the attachment plaques of hemidesmosomes composed of?
Desmoplankins such as BP230, which attaches intermediate filaments to the attachment plaque
Plectin
Erbin
Attachment plaques of hemidesmosomes are attached to basal lamina by what transmembrane proteins?
BP180/Type 17 collagen, also known as anchoring filaments
Integrins
What is bullous pemphigoid?
Autoimmune condition where high levels of antibodies are formed against BP180 and BP230
Absence of functional BP230 causes blistering of the skin due to fluid build up between epidermis and dermis
How do focal adhesions connect cytoskeleton to the ECM?
Linking actin filaments to ECM proteins
Consists of 3 faces:
Cytoplasmic face-actin filaments
Transmembrane face-integrins
Extracellular face-laminin and fibronectin
What is merocrine secretion?
Secretion is release by exocytosis
ex. sweat glands
What is holocrine secretion?
Whole cell ruptures during release of product
ex. sebaceous glands
What is apocrine secretion?
Apical cytoplasm is lost with the secretion
ex. mammary gland
What are serous glands?
Secrete protein secretion, cytoplasm contains zymogen granules
Ex. exocrine pancreas, parotid
What are mucous glands?
Produce mucin, PAS positive, water soluble, cytoplasm appears foamy or vacuolated
Ex. sublingual salivary gland
Which organs epithelial tissue is arranged in the form of epithelioids?
Pancreas
Where is site of inflammatory reactions?
Loose connective tissue
What do fibroblasts secrete?
Collagen, elastin, reticular fibers, ground substance
Collagen biosynthesis
Genes for pro-a1 and pro-a2 chains are transcribed
mRNA moves into cytoplasm and interacts with ribosomes, after translation, it is referred to as pre-pro-polypeptide chain
Chain travels to rER for post translational modification
Three major modifications are made to chain for it to become pro-collagen:
The signal peptide on the N terminal is removed
Lysine and proline residues get additional hydroxyl groups added to them via hydroxylase enzyme which REQUIRE VIT C
Glycosylation of the selected hydroxyl groups on lysine with galactose and glucose b
Three of the hydroxylated and glycosylated pro-a-chains assemble by twisting into triple helix by pro-collagen
Procollagen molecules move to golgi via COPII, get packaged into secretory vesicles and ready to enter ECM
Enzymes known as collagen peptidase cleaves procollagen and molecule becomes Tropocollagen
Lysyl oxidase, copper dependent enzyme acts on lysine and hydroxylysines and tropocollagen molecules form covalent bonding between them, becoming collagen fibril
What is required for collagen biosysnthesis?
Vitamin C
What are myofibroblasts involved in?
Wound healing
What are classically activated macrophages M1?
Secretes interlukins to start inflammation, starts diapedesis
What are alternatively activated macrophages M2?
Not involved in phagocytosis, anti-inflammatory, stimulate angiogenesis, secrete fibronectin which is very important for wound repair/healing, also secretes multiadhesive proteins
What is a foreign body giant cell or Langhans cell?
Macrophages fused together to form large cell when encountering large foreign bodies
What do preadipocytes within lateral mesoderm form?
White adipocytes
What do preadipocytes within paraxial mesoderm form?
Brown adipocytes
What is function of brown adipocytes?
Mitochondrial metabolism of brown adipocytes releases heat rather than ATP
What is function of white adipocyte?
Storage of fat and energy as triglyceride lipid droplet, provides insulation and cushioning to vital organs
What does white adipocytes function AS and produce what?
Major endocrine organs
Produces Angiotensinogien AGE, Steroids, Leptin (which targets hypothalamus and regulates eating behavoir)
What are brown adipocytes associated with?
Capillaries and direct sympathetic innervation
Where do mast cells arise from?
Mast cell progenitors in bone marrow
What stimuli do mast cells respond to most?
Histamine and tryptase
What are mast cells preformed mediators?
Histamine, serine proteases which are typtase and chymase (generates angiotensin II in vascular injury), eosinophil and neutrophil chemotactic factors, heparin
What are mast cells newly synthesized mediators?
Leukotriene C (causes bronchiospasm), tumor necrosis factor alpha, several interleukins
What is mast cell metochromatic property?
Granules in cytoplasm that interact with chemical in blue dye and turn purple or blue
What are B lymphocytes?
Originate in bone marrow, can differentiate into plasma cells; secrete antibodies
What are T lymphocytes?
Originate in bone marrow, mature in thymus, function in cell immunity, memory cells
What are plasma cells?
Derived from B lymphocytes, produce specific antibodies to specific antigen
What characteristic do plasma cells have?
Clumps of heterochromatin and euchromatin that looks like cartwheel or clock face arrangement
What cells have receptor for IgE?
Mast cell and basophils, both cells have histamine and heparin
What is proteolytic degradation in collagen breakdown?
Occurs outside the cell via matrix metalloproteinases, invasive cancer cells secrete MMPs to break down ECM
What is most common collagen type?
Type 1, occurs in loose and dense CT, bone, and skin
Strong, provides tensile strength, if lost than bone is effected
Synthesized by osteoblasts
What is osteogenesis imperfecta?
Mutation of type 1 collagen gene, brittle bones
What is type 2 collagen?
Present in cartilage, vitreous body of eye
Synthesizes by chondroblasts
What is Kneist dysplasia?
Mutation of type 2 collagen gene, restricted joint mobility, holes in cartilage, will not reach correct height
What is type 3 collagen?
Reticular fibers
Synthesized by fibroblasts, reticular cells in bone marrow, smooth muscle cells
What is Ehlers-Danlos syndrome?
Mutation of collagen types 1,3,4,5
Hypermobility of joints, fragile skin, rupture of vessels and internal organs, delayed wound healing
What is type 4 collagen?
Present as meshwork sheets in basal lamina
Synthesized by epithelial cells, muscle cells, schwann cells
What is alport syndrome?
Renal failure due to structural changes in glomerular basement membrane of kidneys, hearing loss, ocular lesions
What is type 5 collagen?
Dense irregular CT, placenta, bone, blood vessel wall
What is type 7 collagen?
Anchoring fibrils
Synthesized by fibroblasts
What is dystrophic epidermolysis bullosa including kindler syndrome?
Severe blistering and scarring of skin after minor trauma, absence of anchoring fibrils
What are elastic fibers formed by?
Fibrillin microfibrils embedded in cross linked elastin
Synthesized by fibroblasts
The cross links between elastin subunits consist of what?
Desmosine, each of which involves 4 converted lysins into two elastin molecules, forming coiled appearance to elastic fiber
Elastin in elastic arteries is synthesized by what?
Smooth muscle cells, NOT fibroblasts
What are effects of sunlight on elastic fibers?
Fiber disintegration
Fiber thickening
Fiber proliferation
Contribute to decreased skin elasticity and appears as deep wrinkles
Where are reticular fibers/type 3 collagen formed?
In loose CT-formed by fibroblasts
In hematopoietic and lymphatic tissues-formed by reticular cells
What does ground substance contain?
Proteoglycans which are GAGs bound to a core protein
Multiadhesive glycoproteins
Glycosaminoglycans GAGs
Why is hydration of ECM is important?
So substances can diffuse through, resists compression and gives support
Negative charge to GAGs attracts water, resulting in formation of?
Highly hydrated gels; permits diffusion of water soluble substances
Failure of degredation results in accumulation of GAGs in genetic disorders like?
Hurler syndrome
Hunter syndrome
Sanfilippo syndrome
Morquio syndrome
What glycosaminoglycan exists as just a GAG, not as a proteoglycan?
Hyaluronic acid, does not attach to core protein
What does aggrecan exist in cartilage as?
Aggrecan-hyaluronan aggregates
What is perlecan?
Proteoglycan in all basal lamina
What is aggrecan?
Large proteoglycan with core protein bound with keratan sulphate and chrondriotin sulphate
What are examples of multiadhesive glycoproteins?
Laminin-binding sites for type 4 collagen, integrins, and specific proteoglycans
Fibronectin-binding sites for collagen and specific GAGs and integrins, important for cell adhesion and cellular migration through ECM
Tenascin-present in embryonic tissue and wound healing
Osteopontin-binds to osteoclasts and attaches them to bone, plays role in calcification of ECM
What do chondrocytes secrete?
Type II collagen, and ECM
What does hyaline cartilage consist of?
Type II collagen, proteoglycans, multiadhesive glycoproteins
What does elastic cartilage consist of?
Elastic fibers and elastic lamellae (condensation of fibers), type II collagen, proteoglycans, multiadhesive glycoproteins
What does fibrocartilage consist of?
Type 1 and type II collagen, proteoglycans, multiadhesive glycoproteins
What do fibroblasts secrete?
Type 1 collagen
Where can fibrocartilage be found?
Knee meniscus, pubic symphasis, intervetebral discs
Where can hyaline cartilage be found?
Nose, articular joint, costal cartilage, trachea, larynx, bronchi of lungs
Where can elastic cartilage be found?
Pinna of ear, epiglottis
What three GAGs does aggrecan hyaluronan aggregates have?
Chondrotin sulfate, hyaluronan, keratan sulfate
What does type IX collagen do in cartilage?
Facilitates fibril interaction with matrix proteoglycan
What does type X collagen do?
Organizes fibrils into three dimensional hexagonal lattices
What does type XI collagen do?
Regulates fibril size
What is role of multiadhesive glycoproteins in cartilage?
Influence the interaction between chondrocytes and matrix molecules
ex. Anchorin CII helps anchor chondrocytes to matrix, acts as collagen receptor on chondrocytes
What is clinical significance to multiadhesive glycoproteins?
Used as markers to detect cartilage turnover and degeneration
What is important role of aggrecans to cartilage ECM?
Binds water molecules with high affinity, hydrated ECM matrix provides resilience and diffusion of metabolites
What does calcification of ECM do to cartilage (happens with aging)?
Results in chondrocyte cell death
Where is highest concentration of proteoglycans, hyaluronan and multiadhesive glycoproteins at?
Capsular matrix, and only has type VI collagen fibrils
What does territorial matrix of cartilage contain?
Randomlly arranged type II collagen fibrils, less concentration of sulfated proteoglycans
What type of collagen assembles in interterritorial matrix?
Type II collagen
What concentration of proteoglycans does interterritorial matrix have?
Lowest concentration
What transcription factor triggers chondrogenic nodules to differentiate into chondroblasts?
SOX-9
What is endomysium made of?
Type 3 collagen, contains finest capillaries
What is perimysium made of?
Thick collagen, contains larger blood vessels
What is epimysium made of?
Type 1 collagen, contains major nerve and blood vessels
What does Titin do?
Center the thick filaments in middle between 2 z lines, also prevents excessive stretching of sarcomere
What does alpha actin do?
Anchors actin filaments to z line
What does nebulin do?
Helps alpha actin anchor actin filaments to z line, maintains length of actin filaments
What does myomesin do?
Has myosin binding protein, attaches mysoin filaments with each other, holds myosin filaments at M line
What does Mysoin binding protein C do?
Helps myomesin with its function
What does dystrophin do?
Attaches actin to laminin in the external lamina
What can be complication if dystrophin is abnormal?
Skeletal muscle contraction complications, Duchene muscular dystrophy
What does desmin do?
Attaches z discs to each other, and attaches z disc to the sarcolemma using linkage protein ANKYRIN
What is the length of TRIADS?
A-I junction to A-I junction
What are cardiac muscles characterized by?
Large mitochondria
What three types of junctional complexes are found in cardiac muscle?
Fascia adherens, macula adherens, gap junctions
What are e-cadherins dependent on?
Calcium
Where can fascia adherens be found in cardiac muscle?
Transverse portion
What do fascia adherens attach to in cardiac muscle?
Actin filaments of last sarcomere
Where are gap junctions located in cardiac muscle? What do they provide muscle?
Lateral portion
Allows communication and cardiac muscles to work as syncytium
What is the length of DIADS?
Z line to Z line
How are smooth muscle cells attached?
GAP junctions, called NEXUS junction
What are the intermediate filaments of cytoskeleton smooth muscle made of?
Desmin and (vimentin in blood vessels)
What thin filaments and intermediate filaments in smooth muscle attached to?
Dense bodies
Why is smooth muscle thrown in different directions when contracting?
Desmin attached to sarcolemma
What does smooth muscle have lots of that induce cisterna to discharge and regulate calcium?
Caveolin lipid rafts
What does smooth muscle have abundantly in extracellular area?
Reticular fibers
What thin actin filaments does smooth muscle contain?
Caldesmon and calponin, actin, tropomyosin
What do caldesmon and calponin do?
Actin binding proteins that block myosin binding sites, action is calcium dependent
What is arrangement of myosin II in smooth muscle?
Side-polar thick filament
What do smooth muscle cells synthesize?
CT matrix, type 4 collagen, type 3 collagen, synthesizes type 1 collagen and elastin in blood vessels, synthesizes proteoglycans and glycoproteins
What is repair process for smooth muscles?
Regenerate easily, can use undifferentiated stem cells
What is repair process for skeletal muscle?
Myocytes and myotubules
What is repair process for cardiac muscle?
Scar tissue formation for minor injury, cannot repair extensive injury
What is glycophorin A in RBCs?
Attachment to band 3, contains antigenic sites for determning ABO blood types
What is glycophorin C in RBCs?
Attachment to membrane lattice and plasma membrane
What is band 3 protein?
Stabilizes plasma membrane by means of attachment to submembranous lattice, anchors cytoskeleton proteins, binds hemoglobin, anion transport
What is spectrin?
Main peripheral membrane protein in plasma membrane, forms lattice of spectrin and contributes to the shape of erythrocytes and provides elastic properties
What is spectrin anchored to lipid bilayer by?
Band 4.1 protein and ankyrin complex
What is band 4.1 protein?
Contains band 4.1, actin, tropomyosin, tropomodulin, and adductin
Interacts with glycoprotein C
What is ankyrin protein complex?
Contains ankyrin and band 4.2 protein
Interacts with band 3 protein
Binds integral membrane proteins to the spectrin lattice by forming complex with band 4.2 protein
What causes rouleuax formation (coin stacking RBC)?
Increased levels of plasma immunoglobulin
What do WBC granulocytes and agranulocytes both have?
Primary granules, called Axurophilic granules- function as lysosomes
What granulocytes does WBC have?
Neutrophils, eosinophils, basophils
What agranulocytes does WBC have?
Monocytes, lymphocytes
What is most common circulating leukocyte?
Neutrophils
What is least common circulating leukocyte?
Basophil
What do azurophilic granules contain?
Myeloperoxidase, neutrophil defensin, acid hydrolases
What do neutrophil small granules contain?
Enzymes, antimicrobial peptides, membrane proteins
What do neutrophil tertiary granules contain?
Phosphatases, metalloprteinases-(break down ECM)
What is diapedesis?
Local tissue response leads to cytokine release
Cytokines signal post capillary venules to insert selectins E and P
Passing neutrophils attach to selectins
Neutrophil secretes integrins and endothelial cells produce integrin ligand ICAM-1
Neutrophils get firmly attached
Neutrophils put out pseudopodia and migrate into loosened ECM CT (ECM loosened by heparin and histamine secreted by perivascular mast cells)
Proteases secreted by neutrophil destroy basement membrane, neutrophil becomes active in CT matrix and move towards injury site
What reactions are eosinophils associated with?
Immediate allergic reactions, Helminth and parasitic infections
What characteristic do eosinophils have?
Crystalloid body, secretes major basic proteins
What do histaminases do in eosinophils?
Neutralizes histamines, reduces allergic reaction
What do mast cells and basophils have in common?
Histamine and heparin
IgE antibody surface receptors
What is the only cell that can circulate between lymphoid tissue and blood?
Lymphocyte
What do NK cells secrete?
Perforins, Granzyme (proteases)
What does the granulomere (inner) part of glycolyx coat contain?
Alpha granules, delta granules, lambda granules/lysosomes, microperoxisomes
What do platelet alpha granules do?
Facilitate blood coagulation and platelet aggregation, growth factors
What do platelet delta granules do?
Facilitate platelet adhesion and vasoconstriction
Contain ADP and ATP, serotonin, histamine
What do platelet lambda granules/lysosomes do?
Hydrolytic enzymes function in clot reabsorption
What is platelet open canalicular system?
Invaginations of plasma membrane
What is platelet dense tubular system of hylomere?
Stores calcium ions
