General Pathology > Normal Cells and Matrix > Flashcards

Normal Cells and Matrix Flashcards

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1
Q

What are cells?

A
  • Organizational unit of an animal
    • Building blocks of tissues and organs
  • Provide focal point for learning pathology
  • All cells originate from a single primordial cell
    • Differentiates into a diverse population of different cells
  • Cell functions are highly interrelated
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2
Q

What is the plasma membrane?

A
  • A lipid bilayer interspersed with membrane proteins
  • Membrane proteins are critical for cell function and communication
  • The membrane is fluid and constantly changing
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3
Q

What is Cytosol?

A
  • Fluid that bathes all intracytoplasmic organelles
  • Site of most intermediary metabolism
  • Accounts for 50 - 60% of the total cell volume
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4
Q

What is mitochondria?

A
  • Responsible for energy production
  • Oxidative phosphorylation
    • 18x more efficient than anaerobic glycolysis
  • Energy is released as electrons move down the electron transport chain
    • ATP
  • May have originated as intracellular prokaryote
    • Rickettsia prowazekii
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5
Q

What is the Endoplasmic Reticulum?

A
  • Membrane-bound space where proteins, lipids, and carbohydrates are produced
    • These can be incorporated into organelles or are secreted
  • Rough ER produces proteins
    • contains ribosomes
  • Smooth ER produces lipids
    • Detoxification reactions also occur here
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6
Q

What is golgi apparatus?

A
  • Membrane-bound sacs that are closely associated with the ER
    • it modifies, sorts and exports products of the ER
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7
Q

What are Lysosomes?

A
  • Membrane-bound sacs of enzymes
    • primary lysosomes bud from the golgi apparatus
    • Secondary lysosomes are primary lysosomes that fuse with other organelles or cytoplasmic vacuoles
  • They degrade macromolecules d extracellular material taken up by the cell
    • Contents are predominately hydrolases
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8
Q

What are peroxisomes?

A
  • Small enzyme-containing vesicles
  • Mainly a site of oxidative reactions
    • Catalase accounts for 40% of protein content
    • Catalase converts H2O2 to H2O
  • Detoxification and fatty acid breakdown also occur here
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9
Q

What are the functions of the Cytoskeleton?

A
  • Provides properties of shape, organization and movement to a cell
  • Cytoskeletal assembly and disassembly is regulated by calcium
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10
Q

What proteins made up the cytoskeleton?

A
  • Microfilaments
  • Microtubules
  • Intermediate Filaments
  • Regulatory proteins
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11
Q

What is the Nucleus?

A
  • The location of chromatin
    • Chromatin consists of cellular DNA and associated proteins
    • Chromatin is organized into chromosomes
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12
Q

What is the nuclear evelope?

A
  • 2 layered membrane
  • separates the nucleus from the cytoplasm
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13
Q

What is the origin of a cell?

A
  • All cells are derived from a single primordial cell ; the zygote
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14
Q

What are the types of embryogenic cells?

A
  • Ectoderm
  • Mesoderm
  • Endoderm
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15
Q

What is made from Ectoderm?

A
  • Forms a cephalic disc and a neural tube
  • Cells and tissues derived from ectoderm include:
    • Central and peripheral nervous systems
    • Sensory epithelium
    • Epidermis
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16
Q

What is made from the Mesoderm?

A
  • Somites located adjacent to the neural tube
  • Cells and tissues derived from mesoderm include:
    • Connective tissue (mesenchyme)
      • Fibroblasts, osteoblasts, chondroblasts
    • Muscle
    • Kidney
    • Heart and blood vessels
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17
Q

What is the Entoderm?

A
  • Originates as a flat disc by the ectoderm
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18
Q

What is made from the Entoderm?

A
  • Gastrointestinal epithelium
  • Respiratory epithelium
  • Parenchymal organs
    • Liver
    • Pancreas
    • Endocrine glands
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19
Q

What is Cell Replication?

A
  • “The cell cycle”
  • Complex and critical to normal cell development and homeostasis
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20
Q

What is cell differentiation?

A
  • Most cells are adapted to perform a specific function
    • Neurons
    • Osteoblasts
    • Hepatocytes
    • Many more
  • Functions of cells are highly interrelated
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21
Q

How do cells grow and differentiate?

A
  • Depends on its microenvironment
    • Growth factors and other cytokines
      • regulate many cell activities within an organism from embryogenesis to aging
    • Features of the extracellular matrix
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22
Q

What are developmental anomalies?

A
  • Growth and differentiation of each cell line needs to occur in a well orchestrated and coordinated manner or sad things happen
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23
Q

Why do cells interact?

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A
  • A cell must be able to interact with it’s environment and other cells
    • Exchange nutrients/wastes, secretion of products, responding to stimuli, communication
      • For Homeostasis
      • For Coordination of activity
24
Q

What are the mechanisms of Cell interactions?

Study These Flashcards
A
  • Membrane pumps and enzyme systems
  • Receptors
    • Hormone and cytokines
  • Cell-to-cell connections
    • Membrane interactions (antigen presentation)
    • Channels between adjacent cells (connexins)
  • Exocytosis
  • Endocytosis
    • Pinocytosis
    • Phagocytosis
25
What are the mechanisms of intercellular interactions?
* Autocrine * self stimulation * Paracrine * Stimulate local cells * Endocrine * Stimulate cells throughout body
26
What is the Extracellular matrix?
* Structural framework in which cells organize, move, and interact * Has structural, adhesive, and absorptive components * Provides sites for cell adhesion and a conduit for exchange of cell nutrients and wastess
27
What are the functions of the ECM?
* Dictates tissue architecture and organization * Has specific features for each tissue/organs * Regulates or modifies many cell activities * Serves as a reservoir of growth factors and bioactive molecules * Constantly remodeling and changing
28
What are the components of the ECM?
* “matrisome” consists of over 300 different proteins * Fall into 3 categories: * Structural * Absorptive * Adhesive
29
What is the function of the structural components of the ECM?
* Build the framework for cells to exist upon and within
30
What are the Structural components of the ECM?
* Collagen * many types exist * Elastin * most prominent were elasticity is needed
31
What are the types of Collagen?
* 28 different types of collagen * I - Structural collagen of most tissues * fibrous tissue, bone * II - Major component of cartilage * IV - Basement membranes
32
What is the function of the Absorptive components of the ECM?
* Absorb water and other soluble substances which bathe surrounding cells * Exert important osmotic pressures to help maintain water balance
33
What are the major absorptive components of the ECM?
* Glycosaminoglycans * Proteoglycans * Proteins with GAG side-chains
34
What are glycsaminoglycans (GAG)?
* Polysaccharides * 4 main groups: * Hyaluronic acid * Heparan sulfate * Chondroitin/dermatan sulfate * Keratan sulfate
35
What is the function of the Adhesive components of the ECM?
* Sites of attachment for structural ECM components and cells * Mediate interactions of fixed or mobile cells with the ECM
36
What are the adhesive components of the ECM?
* Fibronectin * Laminin * Many others
37
What is Fibronectin?
* A cell adhesin * Links cell membrane integrins to ECM components * such s collagen and proteoglycans)
38
What is Laminin?
* Major component of basement membranes * along with Type IV collagen * Binds cell membrane integrins
39
What are some ECM abnormalites?
* ECM impacts all organs and tissues in the body * Defects of any component can result in a wide variety of conditions * Skin, Bone, and joint disease (collagen dysplasia's) * Muscle disease * Fibrosis * Neoplasia * Cardiovascular disease * Inflammation
40
What are the connections between cells?
* Various types of junctions link cells together to provide functional attributes to populations of cells * Adhering junctions * Tight Junctions * Gab Junctions * Desmosomes / Hemidesmosomes
41
What are cardiac myocytes?
intercalated disks connect cardiac myocytes to each other * Includes: * Desmosomes - mechanical coupling * Fascia adherens (anchoring junctions) - mechanical coupling * Gap Junctions - electrical transmission between (depolarization cue) - electrical couplimg
42
What is the result of Intercalated disc abnormalities?
* Damage (often ischemia / inflammation) to any component of the intercalated discs can lead to heath disease * Arrhythmia * Ventricular hypertrophy * Cardiomyopathy * Any of these can result in either acute or chronic heart failure
43
How are Enterocytes connected?
* Desmosomes * linking of cytoskeletons via **cadherin molecules** * Adherens junctions - (Zonula adherens) * Linking of cells via actin molecules * Gap Junctions * Connexins that allow small molecule exchange * Tight Junctions - (Zonula occludens) * Tight binding to form a seal between cells with selective permeability
44
What are enterocyte tight junction abnormalities?
* Over 40 different macromolecules are identified as contributing to tight junction * Major families of molecules include occludins, claudins, Junction Adhesion Molecules (JAMs), and tricellulins * Pathogenic enteric bacteria toxins, inflammation or non-inflammatory stimuli can disrupt the tight junction * Leaky intestine can expose the body to intralumenal components that can cause disease * Loss of fluid and electrolytes (diarrhea) * Systemic bacterial invasion (bacteremia and endotoxemia) * Antigen exposure and hypersensitivity or autoimmunity * Food or respiratory alergies (due to activation of mucosal immunity) * Immune-mediated islet cell destruction and type I diabetes mellitus * Metabolic disorders * Type II diabetes mellitus * Obesity * Chronic inflammatory bowel disease
45
How does aging affect cells?
* Functions of all cells and tissues progressively decline with age * Mechanisms: * Altered gene expression * Telomere shortening * Progressive metabolic injury
46
What does an aging cell look like?
* Irregular nuclei * Vacuolated mitochondria * Reduced endoplasmic reticulum * Lipofuscin * Accumulation of metabolic products
47
What is Apoptosis?
* Physiological cell death * This is the mechanism to remove damaged or unneeded cells in the least disruptive way possible * Maintains homeostasis, but can also be involved in pathological states * **Active process** that **requires energy** from the cell
48
What are the physiologic causes of Apoptosis?
* **Patterned death** during embryogenesis * **Hormone/cytokine-induced** death * Tissue involution * Maintain balance in proliferating populations * Removal of cells following completion of their purpose * Inflammatory cells following the end of the stimulus * Removal of **self-reactive lymphocytes**
49
What is the mechanism of Apoptosis?
* Initiation phase * Extrinsic pathway * Intrinsic pathway * Execution phase * Considerable overlap between the pathways and multiple areas where these can be modified to influence the outcome of the process
50
What is the Extrinsic Pathway for Apoptosis?
* Death receptor pathway * Membrane receptors are activated that contain a cytoplasmic death domain * TNF receptor family **- activated by TNF** * Fas (CD 95) - **activated by** **Fas-ligand** * **Activation leads to autocatalytic activation of procaspase 8**
51
What is the Intrinsic Pathway?
* Mitochondrial Pathway * Survival factors/growth factors stimulate production of anti-apoptotic Bcl-2 and Bcl-x * Maintain mitochondrial membrane integrity * Inhibit activation of Apoptosis activating factor-1 (Apaf-1) * Loss of survival factor stimulation or injury stimulates production of pro-apoptotic Bax, Bak, Bim * Loss of Bcl-2/Bcl-x increases mitochondrial permeability * Mitochondrial proteins (cytochrome C) leak into the cytosol * Cytochrome C activates Apaf-1, which then activates procaspase 9
52
What is the execution phase of apoptosis
* Various stimuli can initiate apoptosis, but they all converge to one final pathway * Caspases mediate this pathway * **Caspases 3, 6, 7 are the main “executioner” caspases** * End result is **cleavage of structural and functional cell proteins**
53
What are the Modifications present with Apoptosis?
* Many pro- and anti- apoptotic factors that can modify an initial signal for apoptosis, including: * **Pro-apoptotic** * **Bak, Bax, Bim** * **Smac/DIABLO** * Second mitochondria-derived activator of caspases * **Anti-apoptotic** * **Bcl-2 and Bcl-x** * **IAP** (Inhibitor of Apoptosis Protein)
54
What is the morphology of a cell going through apoptosis?
* **Cell shrinkage** * **Condensation** of cytoplasmic and nuclear components * Formation of membrane-bound vesicles * **Apoptotic bodies** * **No inflammation** or host response to the dead cell
55
What are the pathologic causes of apoptosis?
* **Unrepaired DNA damage** * Damaged transformed cells * **Heat** * **Hypoxia** * Mitochondrial injury * **Viral infection** * **Physical pressure** * ureteral or secretory duct obstruction
56
What are the diseases caused by abnormal apoptoss?
* Autoimmunity * Developmental anomalies * Neoplasia * Inflammatory disease * Neurodegeneration * Cardiovascular disease * Hepatic disease * Among others
General Pathology
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