Histology Flashcards
Muscle tissue: describe the basic fiber characteristics. Name the 3 types of muscle tissue.
- Elongated cells specialized for contraction. Shortest in smooth muscle of vessels.
- Arranged in parallel sheets or aggregated bundles (Sm. muscle).
- Smooth, Cardiac, and Skeletal
Identify and Describe structural features of smooth muscle.
- Grouped, fusiform cells, overlap.
- Eosinophilic. No cross-striactions.
- Long, central nucleus.
- Little extracellular CT.
Identify and Describe the following Smooth Muscle component:
-Sarcolemma
-Sarcolemma: cell membrane and external lamina of smooth muscle. Has many gap junctions and caveolae: regulate Calcium release.
Identify and Describe the following Smooth Muscle component:
-Sarcoplasm
-Sarcoplasm: cytoplasm of muscle fiber. SR stores Calcium. Has mitochondria, myofilaments, and dense bodies.
Identify and Describe the following Smooth Muscle component:
-Myofilaments
-Myofilaments:
Thick filaments: myosin
Thin filaments: actin. Tropomyosin, Calmodulin. Attach to dense bodies via alpha-actinin.
Intermediate filaments: Desmin, Vimentin, Attach to dense bodies via alpha-actinin.
Identify and Describe the following Smooth Muscle component:
-Dense bodies
- Located on sarcolemma and in sarcoplasm.
- Attachments for thin/intermediate filaments as well as adherent junctions.
- Transmits contractile force to adjacent cells and endomysium (CT)
Describe the relationship of the 3 CT layers seen in muscles.
- Endomysium (inner)
- Perimysium
- Epimysium
- Endomysium: surrounds individual muscle fibers/cells. made up of thin loose CT containing Fibroblasts, Largely reticular fibers (Type II collagen fibers, hold ells together during contractions), Nerves/Capillaries.
- Perimysium: thin loose CT septa. Surrounds fascicle (bundle of muscle fibers).
- Epimysium: not prominent in Smooth m (deep investing fascia). Surrounds entire muscle.
Describe the regenerative capacity of Smooth muscle.
After injury, viable cells undergo mitosis and replace damaged tissue. Hyperplasia: increase in number of cells.
Describe the pathway of the respiratory tree.
- Nasal cavities, Nasopharynx, Larynx, Trachea, Primary bronchi, Intrapulmonary bronchi, Terminal Bronchioles.
- Respiratory bronchioles, Alveolar ducts Alveolar sacs, Alveoli.
Identify and Describe respiratory epithelium.
- AKA?
- What does it line?
- 5 Cell types?
- AKA pseudo stratified ciliated columnar epithelium.
- Lines conduction portion of respiratory system (down to terminal bronchioles).
- Ciliated columnar, Basal, Goblet, Brush, Small granule.
Identify and Describe the 5 cell types of respiratory epithelium.
- -Ciliated columnar: abundant apical cilia.
- -Basal: small round cells at BM. Stem cells.
- -Goblet: dome shaped apical surface. Give sandpaper texture to apical surface. Produce mucin.
- -Brush: Chemosensory receptors. Blunt microvilli.
- -Small granule (Kuchitsky): dense core granules at basal surface. Hard to see.
Identify and describe the 3 layers of the tracheal wall.
- Mucosa (inner). Respiratory epithelium underlain by Lamina propria (loose fibroelastic CT and mucous/seromucous glands), then Elastic lamina fibers that separate submucosa.
- Submucosa (middle). Dense, irregular fibroelastic CT. Seromucous glands. Hyaline cartilage prevent tracheal collapse. Trachealis muscle bridges C-rings posteriorly. Contraction reduces tracheal diameter.
- Hyaline Cartilage is avascular, Type II collagen, Stains fuzzy or glassy. Chondrocytes in lacunae. - Adventitia (outside): Fibroelastic CT anchors trachea to adjoining structures, elastic prevents excessive luminal dissension, contains blood vessels. No definitive edge.
Identify and describe unique characteristics of Primary Bronchi
Similar to trachea but lamina propria is separated from submucosa by SM. Fewer seromucous glands. Flattened hyaline cartilage without distanct rings.
Identify and describe unique characteristics of intrapulmonary bronchi.
- AKA Secondary and Tertiary Bronchi.
- Alveoli surround the gradually decreasing diameter.
1. Mucosa has folded appearance.
2. Submucosa with irregular plates of hyaline cartilage.
Identify and describe unique characteristics of terminal bronchioles.
- No cartilage, No glands, No goblet cells. Clara cells present with dome shaped apical ends projecting into lumen (electron dense apical secretory granules for surfactant and immune defense).
- Lamina propria with lymphocytes.
Identify and describe unique characteristics of respiratory bronchioles.
- Have openings to alveoli for gas exchange. Smooth muscle only near alveoli openings.
- Clara cells.
- No goblet cells, No glands, No cartilage.
Identify and describe unique characteristics of alveolar ducts.
- These are simple squamous epithelium, end in alveolar sacs (grape bunches).
- Smooth muscle strands surround alveolar openings.
Identify and describe unique characteristics of alveolar sacs.
-Larger clusters of alveoli at the end of alveolar duct (occasionally along their length)
Identify and describe unique characteristics of alveoli.
- Fxn
- Components of Interalveolar wall.
- Pores
-Primary site of gas exchange.
- Interalveolar septa (wall) components:
1. Surface epithelium: continuous lining with Type I and II pneumocytes.
2. Capillaries: Form plexus around each alveolus.
3. Supporting CT: Fibroblasts, Macrophages, and Leukocytes. Elastic fibers allow expansion/contraction with respiration. Reticular fibers prevent collapse and excessive dissension of alveoli.
-Alveolar Pores: allow for collateral circulation of air by penetrating inter alveolar septa. Equalize air pressure in alveoli.
Identify and Describe the basic function of the Blood-Air Barrier as well as it’s cellular components.
- AKA respiratory membrane. Thinnest regions of inter alveolar septum. Air in alveoli separated from capillary blood by these 3 components below:
1. Pneumocytes lining alveolus.
2. Fused basal laminae of cells.
3. Endothelial cells of capillary.
Identify and describe the Type I pneumocytes present in alveoli.
- Presence
- Role in Blood air barrier
- Fxn
- 95% of alveolar surface
- Maintain alveolar side of blood-air barrier.
- Desmosomes and tight junctions Prevent ISF flowing into alveolar air space
Identify and describe Type II pneumocytes in alveoli.
- location
- Cell shape
- Fxn
- Thicknesses of the septum
- Cuboidal cells that bulge into alveoli and have short apical microvilli with LAMELLAR BODIES.
- Secrete pulmonary surfactant.
Identify and describe alveolar macrophages.
- AKA
- Shape
- Derivative
- Fxn
- AKA Dust cells
- Irregular shape with pseudopods, lysosomes, and indented nucleus.
- Derived from monocytes.
- Remove dust, bacteria, and phagocyose RBC from damaged capillaries.
Describe how the body reacts to inhalation f toxic gases damaging pneumocytes/alveolar lining.
TYpe II pneumocytes act as stem cells. Create both Type I and Type II. Turnover about 1% per day.
-Clara cells can divide and migrate to give rise to pneumocytes in response to toxic stress as well.
Describe the general layout of lung vasculature and lymphatics.
- Branches of the pulmonary artery follow the bronchial tree, share adventitia.
- Capillary networks are located in inter alveolar septa and surround each alveolus.
- Lymphatic vessels originate in CT of bronchioles and drain into lymph nodes at the hilum. (Won’t see them at alveolar duct or lower).
Identify and Describe mesothelium and loose CT as a part of the pleural membranes.
- Mesothelium is simple squamous epithelium that helps produce serous fluid.
- Underlyin loose CT contains collagen and elastic fibers of the visceral pleura that are continuous with those of the pulmonary parenchyma.
Identify and describe the functions and characteristics of erythrocytes.
- Shape/Contents
- Color pattern
- Describe Rouleax
- Flexible biconcave discs, no nuclei, densely packed with Hgb.
- Pale center, Eosinophilic peripheral zone (pink)
- Rouleaux; cells adhere to one another in stacks.
Identify and describe the functions and characteristics of neutrophils (type of granulocyte)
- 3-5 lobed nucleus.
- Faint/light pink granules
- 1-4 days lifespan
- Phagocytose bacteria
Identify and describe the functions and characteristics of eosinophils (type of granulocyte)
- Bilobed nucleus
- red/dark pink granules
- Specific Granules on EM (hot dog bun)
- 1-2 week lifespan
- Kill helminthic/parasites. Modulate local inflammation
Identify and describe the functions and characteristics of basophils (type of granulocyte)
- Bilobed/S-Shaped
- Dark blue/purple granules. Hard to see on LM.
- Several month lifespan
- release histamine during allergy. Modulate inflammation
IIdentify and describe the functions and characteristics of lymphocytes (type of agranulocyte)
- Spherical nucleus
- Hours-Years lifespan
- Effector and regulatory cells for adaptive immunity
Identify and describe the functions and characteristics of monocytes (type of agranulocyte)
- Indented/C-Shaped nucleus.
- Hours-Years lifespan
- Macrphage precursors
Identify and describe the functions and characteristics of megakaryocytes.
- Giant cells.
- Large, irregularly lobulated nuclei.
- Lightly basobhilic.
- Has pseuodpods.
Identify and describe the functions and characteristics of platelets
- Small, no nuclei, appear in clumps.
- Derived from megakaryocytic.
- Hyalmore: peripheral region is pale blue/pink
- Granulomere: central region: stains darker blue/purple. Delta and alpha granules.
Identify and describe the functions and characteristics of bone marrow (LM only)
- Types
- Components and gen. description
- Red marrow: active hemopoiesis. All marrow in newborns.
- yellow Marrow: filled with adipocytes.
- Stroma: loose CT: Retic fibers (Type III collagen), Stromal cells (fibroblasts), Adipocytes.
- Hemopoietic cords: Islands of cells. erthropoeitic cords closer to caps.
- Capillaries (aka sinusoids): between cords. endothelial lining. Leaky.
