Micro Exam 1

Phospholipids are ___________ to charged, water soluble ion

Impermeable

Phospholipids are ___________ to uncharged polar molecules

Permeable

• cellular barcode

• Phospholipids w/ attached carb

• Immunologic recognition

Glycolipids

• passive

• Via protein channels

Facilitated diffusion

• small polar molecules down conc gradient

• Solute binding site

Carrier protein mediated

• Active

• Requires ATP

Primary pump

• Active

• No ATP

• Powered by movement of co-transported ion down conc gradient

Secondary pump

Direct method of cell signaling

Gap junction:

• connexons

• Cardiac, bone, smooth m cells

Indirect methods of cell signaling

• Contact dependent

• Autocrine

• Paracrine (nonspecific signal)

• Endocrine (bloodstream)

• Mechanical

  • Stretch activated receptors (ECM stretches, channels open)

• 2 actin strands in double helix

• Smallest fibers

• Cross link to form network

• Forms core of microvilli + sterocilia

Microfilament/Actin

Functions of _____:

• Muscle contraction

• Endo + exocytosis

• Cellular movement

• Intracellular movement of materials

• Cell shape changes

• Cytokinesis (following a signal)

• Anchor to cell membrane

Microfilament/Actin

4 protofibrils (1 protofibril = 4 rodlike proteins)

Intermediate filaments

• Hollow tubes

• Largest fiber

• Positive + negative ends

  • + end adds, - end shrinks (dynamic length)

• Associated w/ motor proteins:

  • Kinesin

  • Dynein

• Subunits: alpha + beta tubulin

Microtubules

Motor protein that moves toward + end (take materials)

Kinesin

Motor protein that moves toward - end (return materials)

Dynein

Motor protein on microfilaments/actin

Myosin

1 glucose makes…

30 ATP

Suppresses translation by binding to mRNA (tRNA can’t read it)

microRNA

1. DNA

2. RNA

3. Ribosome

4. Free polyribosome (not attached to membrane)

5. Release to cytoskeleton, organelles, or vesicles

Intracellular proteins

1. DNA

2. RNA

3. Ribosome

4. RER bound polyribosome (making protein inside RER)

5. Golgi apparatus

6. Extracellular delivery

Extracellular protein

• Cytoplasmic filled w/ hydrolytic/digestive enzymes

• Recycles amino acids, free fatty acids, etc (ECM remodeling)

• Stores waste products

• Auto and heterophagy

• Controlled exocytosis

  • Uncontrolled release: chronic inflammation

Lysosomes

Degrades only cellular proteins

Proteosomes

• Destruction of toxins and drugs

• Involved in production of bile and cholesterol

• B oxidation of fatty acids

Perioxisomes

Tissue renewable process only in liver

Mitosis

Replacement tissue renewal

• No mitosis

• Stem cells

• Progenitor cells

  • Muscle: satellite cells

  • Periosteum: osteoblasts, chondroblasts

Which tissues are unrenewable?

Nerves and myocardium

• Programed cell death

• No inflammatory reaction

Apoptosis

• Uncontrolled cell death

• Inflammatory reaction

Necrosis

Reversible change of cell type

Metaplasia

(Neuron part)

• Receptors

• Transport vesicles along cytoskeleton

• Electrical signal

• Chemical signal

Dendrites

(Neuron part)

• Signal processing

• Protein production

  • Intra: cytoskeleton

  • Extra: neurotransmitters

Cell body

Transmitting action potential

1. Na+ and K+ channels open to allow ions down conc gradient

   ATPase pump required to restore resting potential

2. Golgi packages and ships neurotransmitters in vesicles

3. Attached to kinesin (towards +)

4. Moves along microtubule to axon terminal

5. Exocytosis at synapse

Single layer epithelium

Simple

Multilayer of epithelium

Stratified

(type of epithelial layer)

• all cells on basement membrane

• Nuclei on various levels

• Not all reach apical surface

psuedostratified

• width > height

• Can be keratinized

Squamous

Width = height

Cuboidal

Height > width

Columnar

• “Umbrella cells”

• Manage distention

• Kidneys to urethra

Transitional

molecule travels through cell

Transcellular

Molecule travels through cell adhesions (C Diff)

Paracellular

(Cell adhesion)

• Most apical

• Continuous band (occludin)

• Ziplock seal

• Blocks paracellular diffusion of proteins and lipids

  • Tight adhesion, restrict movement

Tight junctions

(Cell adhesions)

• Intermediate barrier

  • Big molecules can’t go through

• Continuous band (e-cadherins binding to actin)

• Transmembrane GPs bind adj. cells together

Adherens junctions

(Cell adhesions)

• Scattered across lateral borders

• Discrete-spot junctions

• Attached to intermediate filaments

• Transmembrane GPs bind adj. cells together

• Disperse physical force

• Cardiac and smooth m

Demosomes

(Cell adhesions)

• Molecular tubes between cells

• Allows small ions/molecules between cells

• Cellular signaling

Gap junctions

• 2 thin layers of extracellular matrix

  • Basal lamina (epithelial)

  • Reticular lamina (connective)

• Selective barrier

• Structural support

• Repair and scaffold

• Bind and conc signaling molecules

Basal membrane

• ECM produced by epithelial cells

• Type 4 collagen

• Laminin (large GP)

  • Attaches basal surface of epithelium to _________

Basal lamina

• Produced by fibroblasts of connective tissue

• Reticular fibers (type 3 collagen)

• Anchoring fibrils of type 7 collagen

• Ground substance

Reticular lamina

• Hemidemosomes

• Focal adhesions

Basal surface anchoring

• Intermediate filaments to integrins to basal lamina

• Mechanotransduction

Hemidesmosomes

• Actin to binding proteins to laminin and fibronectin

• Signaling molecules for adhesions, mobility, and gene expression

Focal adhesions

• Only on simple columnar or cuboidal cells

• Inc absorption

• Propel substances along epithelium

Apical cellular extensions

• Inc surface area

• Core:

  • Actin

  • Actin binding proteins

  • Motor proteins: myosin 1, dyenin, kinesin

• Motion due to actin sliding on actin

Microvilli

• Move fluid over surface

• Mucus in respiratory tracts

• Core of microtubules, linking and motor proteins

• Sweeping motion from micro tubules bending and moving as dynein moves across

Cilia

• Propellor

• Moves through fluid

Flagella

• Long microvilli

• Absorptive (male epidymis)

• Sensory (auditory and vestibular sensory organs)

Stereocilia

(Glands)

Secretion reaches epithelial surface through duct

Exocrine glands

(Glands)

Secretions enter blood vessels for distribution

Endocrine glands

(Glands)

Cell makes enzyme, released through exocytosis

Merocrine glands

(Glands)

Break up themselves

• Lipids from lipid bilayer are released (thick, oily)

Holocrine glands

(Glands)

Only apical part of cytoplasm is released

Apocrine glands

(Product of glands)

Protein, high water content

Serous

(Products of glands)

Glycoprotein (GP), viscous

Mucous

(Products of glands)

Basal nuclei, apical secretory granules

Polarized

• Abnormal or uncontrolled cell growth

• May be reversible early

• Skin: benign or malignant

Neoplasia

• Reversible cell adaptations

• Typically due to external irritants or stress

• May become cancerous

• Ex: esophagus

Metaplasia

Roles of Connective Tissue

• Support other tissues

• Protect other tissues

• Bind other tissues

• Nurture other tissues

• Remodel to adapt to environment

Specialized Connective Tissue

• Blood

• Bone

• Cartilage

• Adipose

• Reticular

_____ Fibers:

• Structural support while allowing size changes (stretch, rebound)

• Small amounts in proper CT

• High amounts in BLOOD VESSELS (aorta: a lot, VC: few), dermis, _____ ligs., _____ cartilage

• Rubber band-like: FIBRILLIN + ELASTIN

• Cross linking

Elastic fibers

_______ Fibers:

• Primarily collagen type 2

• Mesh-like structure

• Supports hemopoietic and lymphatic tissue

• Supports epithelia as _____ lamina

• Surrounds: smooth m cells, axons, etc

Reticular fibers

• Most abundant protein (type 1)

• Alpha chain composition determines type

• Categories:

  • Fibril forming

  • Network forming

  • Linkage/anchoring

Collagen

(Collagen)

• Resist tension

• Provides tissue structure

Fibril forming

(Collagen)

• Highest tensile strength

• Resists forces, tension, and stretch

• Locations: dermis, bone, tendon, lig. fascia, organ capsules, late scar tissue

Type 1 (fibril forming)

(Collagen)

• Medium tensile strength

• Resists intermittent pressure

• Locations: hyaline and elastic cartilage, intervertebral discs

Type 2 (fibril forming)

(Collagen)

• Lowest tensile strength

• Supportive scaffolding

• Loose network, thin fibers

• Locations: granulation tissue (becomes scar tissue), early scar tissue, lungs, blood vessels, endoneurium, other organs

Type 3 (fibril forming)

(Collagen)

• Supports type 1

• Locations: skin, bone, interstitial tissue

Type 5 (fibril forming)

(Collagen)

• Supports type 2

• Locations: cartilage

Type 11 (fibril forming)

(Collagen)

• Supports epithelium

• Inc tissue density

• Locations: basal lamina

Network collagens (4, 10)

(Collagen)

• Anchors basal lamina

• Binds different collagens together

Linking/anchoring collagens

(7, 9, 12, 14)

Collagen Synthesis: order of organelles

1. RER

2. Golgi

3. Extracellular space

   Procollagen → collagen → collagen fibrils → collagen fibers

Collagen synthesis: RER

• mRNA produce alpha chains

  • Inserted into RER

  • proline + lysine predominate (triple helix formation and molecule stability)

• Alpha chains processed

  • Requires VITAMIN C, iron, and oxygen (stabilize, helix formation, strength)

• 3 alpha chains bind together

• Adds molecular caps to end: now a PROCOLLAGEN MOLECULE

Collagen synthesis: Golgi Apparatus

Packed and exocytosis

Collagen synthesis: Extracellular space

• Caps removed: COLLAGEN MOLECULE

• collagen molecules assemble: COLLAGEN FIBRILS

• Fibrils crosslink: COLLAGEN FIBERS

  • Inc tensile strength

  • Chronic hyperglycemia inc crosslinks

• Type 1 forms large fibers and fiber bundles

• Regulator proteins control rate of assembly, size of fibrils, fibers, and bundles, and density of packing

• Mutation of an alpha chains Inserted into in type 1 collagen

• Brittle bones

  • Frequent fractures, short stature, scoliosis, bowing in bones

• Restrictive pulmonary disease

Osteogenesis Imperfecta

• Lack of Vitamin C

  • Unstable alpha chains, impaired triple helix formation

  • Defective dentin

    • Tooth loss, hemorrhage, altered bone growth in children

Scurvy

• Family of disorders

• Genetic mutations

  • Collagen (esp. 1, 3, 5)

  • Enzymes for post translation

• Deficient formation of collagen fibrils

Ehlers Danlos

• Resident cells

• Primary producer of ECM components

• Responds to growth factors

• Active

  • Large, ovoid nuclei

  • Abundant in RER and Golgi

• Quiescent:

  • Smaller nuclei

  • Minimal RER and Golgi

  • Fibrocyte

Fibroblast

• Resident cells

• Fat/energy storage

• Secondary functions: cushion, insulate, heat generation

• Primarily cytoplasm

• Nuclei on edges

Adipocytes

• Residents in most CT

• Oval/kidney shaped nuclei

• Irregular surface (legs)

• Numerous lysosomes, RER, Golgi

• Derived from monocytes (circulating WBCs become ______ once in tissue)

Macrophages

Macrophage Functions

• Phagocytosis

  • Maintain, repair, monitor

  • Foreign material, necrotic cells and debris, ECM material, damaged ECM (# inc w/ injury and inflammation)

• Injury response

  • Oversees inflammatory response

  • Recruits and manages other cells

• Antigen presentation to lymphocytes/WBCs

• Cellular signaling

  • Lymphokines: cytokines produced to attract lymphocytes/WBCs

  • Mediators and resolution of inflammation

  • Growth factors (call for repair crew)

• Collection of macrophage-like cells derived from embryonic monocytes

• Liver: kupffer cells

• CNS: microglia

• Bone: osteoclast

• Epidermis of skin: langerhans

• Lymph nodes/Spleen: dendritic cells

• Pathological conditions: multi-nuclear giant cells

Mononuclear Phagocyte System

• Resident B cells

• Produce antibodies (abundant RER and golgi)

• Neutralizes toxins

• Enhances phagocytosis of antigens (vaccine)

• Activates mast cells and basophils (produces IgEs)

Plasma cells

• Residents in most CTs

• Abundance of secretory granules

• Outer membrane coated w/ IgE antibody receptors

• Prominent in LOOSE CT

  • Dermis, respiratory tract, GI tract

Mast cells

Mast cell functions

• Synthesizes, stores, and releases chemical mediators of inflammation

  • Stored granules (vesicles)

  • Histamine

    • anticoagulant

  • Heparin

    • vasodilation, inc vascular permeability (leakiness) bronchial smooth m contraction (asthma)

  • Prostaglandins

    • everything heparin does, reversed by epinephrine

When are granules released by mast cells?

When IgE binds

• Inflammation begins

• Immediate hypersensitivity reactions

• Abnormal response to harmless substance

• Mast cells release granules to commonly encountered substances

• Anaphylactic shock, allergies

Immediate hypersensitivity reactions

• GAGs, PG, multi-adhesive GPs, tissue fluid

• Amorphous, hydrated, viscous gel

Ground substance

Ground substance functions

• Barrier

• Diffusion

• Cell movement

• Lubricant

• Binding site for chemical signaling factors (growth factors)

• Polysaccharides

• Very hydrophilic

• Hydraluronic acid/hyaluronon: largest, most abundant ____

Glycosaminoglycans (GAGs)

• GAGs linked to a protein core

• Assembled in golgi, exocytosis to ECM

• Cell surface ____:

  • Integral proteins of cell membrane

  • Binds growth factors/cytokines

  • Anchors cell to matrix

Proteoglycans (PGs)