MSK_MT1_ILS1 (Histology of ConnTiss&Muscle) Flashcards

1
Q

Epithelial Tissue

A
  • continuous sheets of cells that line internal surfaces and cover the external surface of the body
  • glands are derived from epithelium
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2
Q

Connective Tissue

A

supports, binds together, and protects tissues and organs.

It is composed of cells in an abundant extracellular matrix.

includes cartilage, bone, and blood.

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3
Q

Muscle Tissues

A
  • cells that have the ability to contract.
  • Uses the contractile proteins actin and myosin.
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4
Q

Nervous Tissues

A
  • specialized for the rapid communication of information from one region of the body to another.
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5
Q

Connective Tissue Function

A
  • Tissue for connecting, linking and holding other tissues.
  • Contains cells and extracellular matrix of fibers and ground substance
  • Function: structural support, defense, repair, storage (water, electrolytes, proteins, fat)

acts as a medium for exchange of nutrients and wastes between the blood and tissues, protects against microorganisms, repairs damaged tissues, and stores fat.

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6
Q

Embryonic Connective Tissue

A

Mesenchymal tissue is found only in embryos.

It consists of a gel-like amorphous matrix, a few scattered reticular fibers, star-shaped (stellate) fibroplasts, pale-staining mesenchymal cells

Mucous tissue (Wharton jelly) is a loose CT located in umbilical cord

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7
Q

Areolar / Loose Connective Tissue

A
  • More ground substance and cells with few fibers
  • Flexible and well vascularized
  • Little tensile strength, not resistant to stress
  • Lamina propria in the digestive tract
  • More abundant than dense connective tissue
  • space filler of deep skin
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8
Q

Dense Regular Connective Tissue

A
  • Abundant collegen fibers arranged in parallel bundles with few cells/ECM
  • strong/resistant to stress
  • skin thick deep layer of dermis
  • Found in tendons, ligaments, aponeuroses
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9
Q

Elastic Connective Tissue

A
  • More elastin-based proteins than collagen
  • Found in large arteries
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10
Q

Specialized Connective Tissue: Adipose Tissue

A
  • Unilocular or white fat
  • secrete hormones/cytokines (eg. leptin and adiponeptin; multilocular or brown fat)
  • Adipocytes contain numerous mitochondria for metabolic generation of heat
  • Flattened nucleus found around the rim of cytoplasm
  • RARELY divides
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11
Q

Connective Tissue Components: Permanent Residents

A
  1. Fibroblasts: synthesize fibers, secrete ground substance
  2. Macrophages: protection and immunity
  3. Mast cells: inflammation, allergy
  4. Adipocytes: lipid storage
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12
Q

Connective Tissue Components: Transient Cells

A
  1. Plasma cells
  2. Leukocytes/ Lymphocytes
  3. Neutrophils and Eosinophils
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13
Q

Fibroblast

A
  1. Most abundant cells, Spindle-shaped
  2. Synthesize fibers (collagen, elastic fibers)
  3. Secrete ground substance
  4. Normally non-mitotic but can replicate
  5. Makes protein: contains rough ER and large Golgi complex
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14
Q

Macrophage

A
  1. Derived from blood monocytes
  2. MIGRATE into CT and stay (histiocytes)
  3. Phagocytic: contains lysosomes and residual bodies
  4. Exist as Kupffer cells in liver
  5. Initiate immune responses (present antigens to lymphocytes); secretehydrolyticenzymes(eg.collagenase);
  6. Can replicate
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15
Q

Mast Cell

A

Contain basophilic cytoplasmic granules that obscure the nucleus

  • Granules contain histamine and heparin (involved in allergic reactions)
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16
Q

Plasma Cells

A
  1. Derived from mitotic B-lymphocytes
  2. Secrete anti-BODIES
    • ​contains rough ER and prominent Golgi complex
  3. Eccentric nucleus with clock-face arrangement
  4. 10-20 day lifespan
  5. Involved in immune response
17
Q

Lymphocytes

A
  1. Smallest free cell in CT (Nucleus occupies most of the cell)
  2. B cells and T cells
  3. Involved in infection, tissue inflammation and immunity
18
Q

Extracellular Matrix is composed of…

A
  1. ground substance
  2. fibers

ECM provides a medium for the transfer of nutrients & waste between connective tissue cells ⇌ the blood stream

19
Q

Ground Substance

A
  • colorless, transparent, gel-like material (contains fibers)
    • glycosaminoglycans, proteoglycans, and glycoproteins
  • Serves as a lubricant, helps to prevent invasion of tissues by foreign agents, and resists compression.
  • in ECM
20
Q

Fibers

A
  • in ECM
  • types: collagen, reticular, and elastic
21
Q

Collagen Fibers

A
  • most common: types I and III collagen
  • Fibroblasts synthesize alpha chain proteins → rER → procollagen → secreted out of cell:
    • Procollagen → tropocollagen → collage → self-assembly takes place outside the cell
  • great tensile strength
22
Q

Type I Collagen Fibrils

A

banding pattern on the surface of collagen fibrils

23
Q

Reticular Fibers

A
  • extremely thin diameter
  • composed type III collagen
  • Stain black with silver salts (b/c high carbohydrate content)
  • Arranged in a mesh pattern
  • Found in small blood vessels, nerves, muscle cells.
  • Present in wound healing and scar tissue
  • Supporting stroma in lymphatic tissue (Reticulocytes)
  • Provide early strength to newly synthesized ECM
    • Gradually replaced* by *stronger Type I collagen
24
Q

Elastic Fibers

A
  • are coiled branching fibers that sometimes form loose networks.
  • These fibers stretch up to 150% of their resting length.
  • They consist of Elastin and thin microfibrils (fibrillin-1 which is bound to elastin)
25
Q

Glycosaminoglycans (GAGs)

A
  • Ground Substance
  • large unbranchedpolysaccharide chains
  • eg. hyaluronic acid, chondroitin sulfate
26
Q

Proteoglycans

A
  • Ground Substance
  • core protein backbone to which GAGs are attached
  • responsible for viscosity and gel-like consistency (binds to water and cations )
27
Q

Adhesive Glycoproteins

A
  • Ground Substance
  • globular protein with short branched carbohydrates
  • eg. fibronectin, laminin
28
Q

Muscle Histology Overview

A
  • sarco = flesh:
  • sarcolemma = plasma membrane
  • sarcoplasm = cytoplasm
  • sarcoplasmic reticulum = endoplasmic reticulum
29
Q

Non-Striated Muscle

A
  • smooth, involuntary
  • located in blood vessels, viscera; hair follicles
30
Q

Striated Muscle

A
  1. skeletal (voluntary): attached to the skeleton
  2. cardiac (involuntary): heart, base of large veins
31
Q

Smooth Muscle

A
  • elongated fusiform shapes with tapered ends
  • Connected by gap junctions
  • Cytoplasm appears evenly eosinophilic in H&E light microscopy (pink)
  • The nucleus.. appears elongated in longitudinal sections, and round in transverse sections
  • contains myosin and actin filaments but NO SACROMERES
  • contains intermediate fibers (desmin and vimentin)
  • type III and type IV collagen