Exam 1 - Microanatomy
Terms
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- 4 Main Tissues
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1. Connective
2. Nervous
3. Muscle
4. Epithelium - Epithelial Characteristics
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-No blood vessels
-Protect, transport, gas exchange, excretion, secretion, absorption
-Derived from ectoderm, mesoderm, endoderm
-Basement membrane - Axoneme
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-Cilia structural unit
-9 microtubule pairs surrounding center microtubule pair - Microvilli
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-Smaller than cilia
-Actin filaments
-"Brush border", intestine - Stereocilia
- Like microvilli but branched
- Calcium Ion Dependent Cell Adhesion Molecules
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-Cadherins
-Selectins - Cadherins
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-Cell adhesion
-Tumor metasasis if cadherins broken
-Use catenins to attach to actin - Catinins
- Lambda, alpha, beta subunits attach cadherin to actin in cell cytoplasm
- Selectins
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-Attach to carbs via lectins
-Used in white blood cell migration (T-cell "homing") -
Selectin Types
(E, L, P) -
E: on active endothelial cells
L: on leukocytes (white b.c.)
P: on platelets and endothelial cells - Calcium Ion Independent Cell Adhesion Molecules
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-Ig Superfamily
-Integrins
-Desintegrins - Ig Superfamily
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-CAM (cell adhesion molecules)
-HIV receptor
-Folded domain like immunoglobins - Integrins
- Attached to outside (fibronectin and laminin) and inside (actin) of cell using alpha and beta subunits
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Transcellular Pathway;
Paracellular Pathway -
-Transcellular: ions, water move through the cell
-Paracellular: travel between cells - "zozamaga"
- zonula occludance, zonula adherance, macula adherance, gap juntions
- Occluding Junctions
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-Use zonula occludance ("belt" around cells)
-Tight junctions between cells
-Near apical domain - Anchoring Junctions
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-Zonula adherance: attach to actin, around cell, below zonula occludance
-Macula adherance: spot "desomosomes"/adherins - Hemidesmosomes
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-NOT intracellular juntion
-Attach basolateral domain to basement membrane
-Assymetrical (don't connect to another hemidesmosome) - Gap Junctions
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-Tunnel between two cells
-Formed by 6 connexins (membrane proteins) - Basement Membrane
- -Basal lamina + Reticular lamina
- Basal Lamina
- Made of laminins from epithelial cells and type IV collagen
- Reticluar Lamina
- Made of fibronectin from fibroblasts in CT
- 6 Cytoskeleton Functions
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1. Mobility
2. Change shape
3. Phagocytosis
4. Support
5. Cell division (cytoinesis)
5. Cell-cell adherance - Microfilaments
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- Part of cytoskeleton
- Made of actin filaments
- G-actin: single unit
- F-actin: chain of G-actin
- "Treadmilling": G-actin added to + end and removed at - end - Microtubules
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- Made of 13 alpha & beta dimers, 25 nm diameter
- Protofilament: column of dimers
- Help in mitosis - Saltatory & Axonal Vesicular Transport
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-Saltatory: continuous & random movement
-Axonal: directional - Kinesin & Cytoplasmic Dynein
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-Motor proteins
-Kinesin: anterograde transport; takes things away from cell center
-Cytoplasmic Dynein: retrograde transport; takes things toward cell center - Myosin II
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-Made of 2 chains (light & heavy)
-Found in muscle & non-muscle - Chromatin Phases: Euchromatin, Heterochromatin, Hyperchromatin, Pyknotic
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-Euchromatin: chromtin is unwound & ready for transcription
-Heterochromatin: chromain is wound, inactive
-Hyperchromain: in small lymphocytes
-Pyknotic: very condensed chromatin, cell is sick/dieing - Barr Body & Drumstick Body
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-Bump is inactive X chromosome in females
-Barr body: in epithelium
-Drumstick body: in neutrophil - Nucleolus
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-Site of rRNA synthesis in nucleus
-Indicates transcription when visible - Mitosis Phases
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-Prophase: chromatin condenses
-Metaphase: chromosomes align on equitorial plate
-Anaphase: sister chromatids divide
-Telophase: nuclear membrane reforms - Parenchyma & Stroma
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-Parenchyma: secreting portion of gland
-Stroma: "home" of parenchyma - Phospholipid Bilayer, Glycolipids, Cholesterol
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-5 diff phospholipids makeup 50% of membrane
-Glycolipids are cell identity markers
Cholesterol: adds stability - ER Leaflets: Exocytoplasmic & Protoplasmic
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Exotyoplasmic: faces lumen of ER
Protoplasmic: faces cytoplasm (cystolic compartment) - Rough ER
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-Ribosomes attached
-Produces proteins for outside of cell
-Sends proteins to golgi - Golgi Apparatus CIS & TRANS face
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-Modifies proteins from rough ER
-CIS: closest to ER
-TRANS: farthest from ER - Primary & Secondary Lysosomes
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Primary: new, not active
Secondary: actively "eating" - Phagocytosis, Pinocytosis, Clathrin-Coated Endocytosis
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- Phagocytosis: cell "eating"
- Pinocytosis: cell "drinking"
- Clathrin-Coated: brings in small macromolecules - 6 Steps of Receptor-Mediated Endocytosis
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1. Ligan attaches to receptor
2. Internalization of complex
3. Clathrin-coating of complex
4. Clathrin-coat detaches
5. Lysosome fuses w/ endosome containing ligand
6. Free receptor taken back to plasma membrane - Mitochondria
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-Produces ATP
-DNA from mother - Outer & Inner Mitochondrial Membranes
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-Outer: pores to allow ions in
-Inner: cristae (folds) & matrix, both where ATP is produced - Peroxisomes
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-Help w/ hydrogen peroxide metabolism
-Synthesize cholesterol & bile salts in liver
-Contain 50 diff enzymes - Syncytial
- Multi-nucleated skeletal muscle cells
- Epimyseum, Perimyseum, Endomyseum
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-Epimyseum: covers entire named muscle, dense CT
-Perimyseum: covers fascicle of muscle
-Endomyseum: covers single muscle cell/fiber - Sarcolemma, Sarcoplasm, Sarcosomes, Sarcoplasmic Reticulum
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-Sarcolemma: plama membrane of muscle cell/fiber
-Sarcoplasm: muscle cell cytoplasm
-Sarcosome: mitochondria
-Sarcoplasmic Reticulum: smooth ER - T-Tubules
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-Carry neural depolarization signal into muscle cell for contraction
-Release signal at A/I junction - Triads
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-In skeltal muscle
-2 sarcoplasmic cisternae (reticulums) around a T-tubule
-Depolarization signal transmitted to sarcoplasmic cisternae - Myofibrils, Sarcomeres
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-Myofibrils: long actin/myosin fibers in a muscle cell
-Sarcomeres: functional unit of muscle, between two Z bands - A, I, M, H, Z Bands
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-A Band: length of myosin, can have actin
-I Band: only actin, takes 2 sarcomeres to form complete I band (straddles Z band)
-M Band: where two sides of myosin combine in H band
H Band: only myosin
Z Band: form boundary of sarcomere - Actin Myofilament
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- Found in A & I bands
- G-actin: globular form
- F-actin: double-stranded fibrous form - Troponin & Tropomyosin
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-Troponin: T, I, & C attached to actin, C not in smooth muscle, Ca binds to tropoinin C so myosin can attach to actin
-Tropomyosin: in groove between 2 actin filaments - Myosin Myofilaments
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-In A & H bands
-Myosin II
-Globular head binds to F-actin during contraction - Nebulin, Desmin, Plectin, Alpha Actinin & Titin
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-Nebulin: template for actin
-Desmin: holds myofibrils together uniformly
-Plectin: binds 2 desmin strands together
-Alpha Actinin: "glue" that sticks actin to Z-band
-Titin: like a spring, keeps myosin in line - What Changes During Contraction
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-Sarcomere length decreases
-H band length decreases as more overlap of actin & myosin
-I band decreases as more overlapping of actin & myosin - What Does Not Change During Contraction
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-A band length cause length of myosin myofilament doesn't change
-Myofilament length of actin & myosin remainse the same - Basal Lamina & Neuromuscular Junction
- Basal lamina holds AcHase to break down AcH neurotransmitters
- Muscle Contraction Steps
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- T-tubule transports signal to triad at A/I junction
- Sarcoplasmic cisternae releases calcium
- Calcium causes release of troponin C from actin & mysosin head attaches and pulls actin
-Calsequestrin puts Ca back into sarcoplasmic cisternae - Cardiac Muscle Differences from Skeletal Muscle
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-T-tubule releases signal at Z band
-"Diad" instead of triad (1 sarcoplasmic cisternae & T-tubule)
-Purkinje fibers act as conducters
-1 nucleus - Intercalated Disks
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-In cardiac muscle
-Gap junctions and horizontal desmosomes between myocytes - Dense Bodies & Lipid Rafts
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-In smooth muscle
-Dense Bodies: striated w/ actin & myosin-like filaments
-Lipid Rafts: indentations, like T-tubules - Contraction In Smooth Muscle
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-No troponin; calmodulin takes its place
-Hormones can stimulate contractions - Red & White Muscle Fibers
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-Red: "slow twitch", high in myoglobin (blood), used for sustained contractions
-White: "fast twitch", low in myoglobin, used for bursts of activity - Development of Nervous System
- -Derived from ectoderm (outermost layer)
- 7 Structures the Neural Crest Derives
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1. Parasympathetic NS
2. Enteric ganglia
3. Dorsal root ganglia
4. Heart
5. Chromaffin cells (adrenal medulla)
6. Schwann cells
7. Branchial arches (face), skull - Neuron Anatomy & Their Functions
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-Stroma: aka perikaryon, cell body, receives & integrates signals
-Dendrites: at least 1 dendrite per neuron, receive signals
-Axon: 1 axon per neuron, transmit signals - Bipolar, Multipolar, Pseudounipolar Neurons
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-Multipolar: has 1 axon & many dendrites
-Golgi Type I: axon is longer than dendrites
-Golgi Type II: axon is shorter than dendrites
-Bipolar: 1 axon & 1 dendrite
-Pseudounipolar: looks to have 1 pole but actually has 2 - Necleus, Neurophil, Lamina, Ganglia
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-Nuclues: cluster of neurons in CNS
-Neurophil: small material & synapses (not large neurons)
-Lamina: neurons in layers
-Ganglia: cluster of neurons outside CNS - Nerves & Tracts
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-Nerves: group of axons outside CNS
-Tracts: group of axons inside CNS - 5 Types of Synapses
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1. Axoaxonic: axon "talks" to another axon
2. Axodendritic: axon talks to dendrite
3. Axospinoous: axon talks to spine of dendrite
4. Axosomatic: axon talks to soma
5. Somatoaxonic: soma talks to axon - Symmetrical & Asymmetrical Synapses
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-Symmetrical (FIGS): flattened vesicles, inhibitory, GABA, symmetrical
-Asymmetrical (AREA): aspartic, round vesicles, excitetory, asymmetrical - Anterograde & Retrograde Axonal Transporte
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-Anterograde: kinesin, soma to axon (away from cell)
-Retrograde: cytoplasmic dynein, axon to soma (toward cell center) - Astrocytes
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-Glial cells (supportive)
-Look like stars - Fibrous & Protoplasmic Astrocytes
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-Fibrous Astrocytes: in white matter (myelinated fibers)
-Protoplasmic Astrocytes: in grey matter - Glia Limitans
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-Glia limitans are foot processes of astrocytes
-Forms blood-brain barrier - Formation of Myelin in CNS & PNS
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-CNS: oligodendroglial cells, no basal lamina so can't repair itself, can myelinate up to 50 different axons
-PNS: Schwann cells, has basal lamina so can repair myelin sheath, can myelinate only 1 segment - Major Dense Line, Minor Dense Line/Intraperiod Line, Mesaxons
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-Major Dense Line: two cytoplasmic leaflets touching
-Minor Dense Line: space between cytoplasm
-Mesaxons: inner (where myelin starts) & outer (where myelin ends) - Nodes of Ranvier, Schmidt-Lanterman Clefts
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- Nodes of Ranvier: gap between Schwann cells
- Schmidt-Lanterman Clefts: splitting in membranes - Microglial Cells Derivation & Functions
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-Derive from mesoderm
-Phagocytose dead neurons
-Immune response - Ependymal Cells & Tanycytes
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-Ependymal Cells: line brain ventricles (cavities)
-Tanycytes: in 3rd ventricle, contact blood vessels - Choroid Plexus
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-Produce cerebral spinalfluid (CSF, filtrate of blood)
-Protects/supports brain
-Removes metabolic wastes - Epineurium, Perineurium, Endoneurium
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-Epineurium: covers entire named nerve
-Perineurium: surrounds a bundle of nerve fibers
-Endoneurium: surrounds individual nerve fiber - Nissl Bodies & Chromatolysis
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-Nissl Bodies: free ribosomes & rough ER in a neuron
-Chromatolysis: Nissl bodies disappear, cell is sick/damaged - Primary & Secondary Demyelination
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-Primary Demyelination: myelin is first to go
-Secondary Demyelination: axon degenerates first then myelin is lost - Plasma (albumins, fibrinogen, immunoglobulins)
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-Plasma: fluid component(92% water, 7% protein)
-Albumins: most abundant protein (50%)
-Fibrinogen: clotting factor
-Immunoglobulins: 2nd most abundant protein
-Also holds hormones, lipids, salts, & waste products - Hematocrit
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-Whole blood
-Plasma (55%)
-Sedimented red blood cells (45%)
-"Buffy coat" (1%, leukocytes & platelets) - Erythrocytes
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-Red blood cells
-7.5 um in diameter
-Live 120 days
-Mature RBCs have no nucleus or organelles - Leukocytes
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- White blood cells
- 7.5-20 um in diameter
- Outside blood vessels
- Functions: phagocytosis & some produce antibodies - Primary & Secondary Granules in Leukocytes
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-Primary Granules: all leukoctyes have them
-Secondary Granules: only granulocyte leukocytes have them - Neutrophil
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-Granuloctye
-Phagocytose bacteria
-First to respond
-Most numerous (60-70%) - Eosinophils
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-Granulocyte
-Combat parasitic infections, clean antigen-antibody complexes
-Stain bright red - Basophils
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-Granulocyte
-Leave blood vessels to become mast cells
-Have histamine granules to initiate inflammatory response & allergic reactions - Lymphocytes
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- Agranulocyte (only contain primary granules)
- B-lymphoctyes & T-lymphocyte
- Large (only 4%) & small
- Hyperchromatic nucleus in small lymphocytes - Monocytes
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-Agranulocyte
-Very good at phagocytosis
-Largest leukocyte (3x larger than a RBC)
-Leave blood vessels to become macrophages
-Give rise to osteoclasts -
Leukocyte Differential:
Never Let Monkeys Eat Bananas -
Never: Neutrophils (most)
Let: Lymphocytes
Monkeys: Monocytes
Eat: Eosinophils
Bananas: Basophils (least) - Platelets
- -Excess cytoplasm from a megakaryocyte
- Commited Progenitor Cells: Lymphoid, Myeloid, 5 Colony Forming Units
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-Lymphoid: produce lymphocytes
-Myeloid: become monocytes or neutrophils
-5 Colony Forming Units:
1. Basophils
2. Eosinophils
3. Granulocyte-Macrophage
4. Megakaryocyte
5. Erythroid - Hematopoeitic Growth Factors: CFU, Erythrophoietin, Thrombopoitin, Interleukens
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-CFU: colony stimulating growth factors
-Erythrophoietin: stimulates RBC production
-Thromoboitin: produces platelets
-Interleukens: like hormones, stimulate leukocyte (WBC) production