Part 1- Connective Tissue Flashcards

1
Q

Main characteristics of connective tissue

A
1- large amounts of ECM between cells
- Ground substance 
- Fibers
A- collagen fibers (Type I)
B- reticular fibers (Type III)
C- elastic fibers

2- variable type and number of cells

  • CT cells: fibroblasts, adipose cells
  • wandering cells: macrophages, plasma cells, mast cells, visiting WBC’s

3- CT contains many blood and lymphatic vessels and nerves

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2
Q

CT is classified according to

A

The predominant fiber type and organization

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3
Q

Adult CT is derived from

A

Mesenchyme tissues

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4
Q

_______ is a malignant neoplasm can develop from CT and fibroblasts

A

Sarcomas

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5
Q

Ground substance

A

Amorphous gelatinous material with high water content occupying the space between cells and fibers

It is composed of tissue fluid with water, electrolytes, glycosaminoglycans, proteoglycans, and multi adhesive glycoproteins (laminin, fibronectin)

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6
Q

Increase fluid in the ground substance results in

A

Tissue swelling or edema

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7
Q

Ground substance allows

A

the diffusion of oxygen, nutrients, waste products, and hormones between cells and capillaries

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8
Q

3 types of fibers present in all connective tissue

A

Collagen fibers (Type I)
Reticular fibers
Elastic fibers

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9
Q

Collagen fibers - made up of? Appearance? Function?

A

Large fibers formed mainly from Type I collagen, most common form of collagen

Easily seen as visible acidophilic bundles

Very strong and flexible, main component in tendons and ligaments

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10
Q

Reticular fibers - components? Appearance? Function?

A

Delicate, thin fibers made of Type III collagen. Fibers cross link to form a meshwork

Visible only with special silver stains

Forms a delicate supporting framework for cells, common in highly cellular lymphoid organs (spleen, lymph node, bone marrow, liver). Forms reticular lamina of basement membranes

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11
Q

Elastic fibers- components? Appearance? Function?

A

Thin, branching fibers made of elastin with microfibrillar proteins

Not visible, unless in large amounts. Special stains usually needed

For stretch and recoil. In elastic arteries like the aorta the fibers are organized into sheets

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12
Q

Types of collagen

A

Types I- IV

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13
Q

Type I Collagen- function and appearance, major distribution, major sources

A

Flexible but strong. Provides resistance to force, tension, and stretch. 90% of all collagen

It’s everywhere! All CT’s including loose, dense regular and irregular. As well as bone, fibrocartilage, dentin, cementum, periodontal ligament.

Fibroblasts, osteoblasts, chondrocytes, chondroblasts, odontoblasts, cementocytes, also smooth muscle

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14
Q

Type II Collagen- function/appearance, major distribution, major sources

A

Resistance to pressure, fibrils visible in EM

Only in cartilage! Hyaline cartilage, elastic cartilage

Chondroblasts, chondrocytes

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15
Q

Type III Collagen- function/appearance, major distribution, major sources

A

Reticular fibers- fibers form a flexible meshwork for cell support. Visible with special stains

All connective tissues! As well as Blood vessels, smooth muscle, nerves, stroma for hemopoietic tissues, stroma for lymphatic tissues

Fibroblasts, adipocytes, smooth muscle, EC’s, smooth muscle cells, Schwann cells, reticular cells. Form reticular lamina of basement membrane!

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16
Q

Type IV collagen- function/appearance, major distribution, major sources

A

Organized into a meshwork. Provides support, attachment to the underlying CT and filtration barriers

Basal lamina

Epithelial cells. Endothelial cells- adipose cells, Schwann cells, all 3 types of muscle cells

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17
Q

Fibroblasts

A

The principal cell of connective tissue

Fibroblasts secrete and maintain the ECM including all fibers (collagen, elastic, and reticular) and most of the ground substance. It is motile and can reproduce

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18
Q

Myofibroblasts

A

Contractile cells that appear in wounds. They display properties of both fibroblasts and smooth muscle cells

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19
Q

A feature of many diverse diseases is overproduction of __________________ as a result of damage

A

Fibroblasts and collagen deposition (fibrosis)

20
Q

Fibroblasts appearance

A

Appear as a long, thin spindle shaped cell with a flat, heterochromatic nucleus. It’s cytoplasm is usually not visible, just its nucleus

21
Q

Adipose cell (adipocyte)

A

Unilocular (white) adipocyte is a large cell with a giant lipid droplet

They store neutral fat

22
Q

Adipose cell appearance

A

In H&E, the lipid is removed leaving a large empty space with a thin, rim of cytoplasm and a flat heterochromatic nucleus pressed to one side. Adipocytes secrete a basal lamina

23
Q

Multiloculat

A

Brown adipocytes primarily present in fetuses and newborns with small remnants in adults

Their cytoplasm contains multiple lipid droplets and abundant mitochondria.

They play a role in heat production, especially around the time of birth

24
Q

Macrophage (histiocyte)

A

Phagocytic cells derived from blood cells called monocytes

25
Q

Monocytes

A

Migrate from the blood into the CT, where they differentiate into a variety of cells including macrophages

26
Q

Macrophages are called ______ in the lung, _______ in the liver. The macrophages of the CNS are called ________

A

Dust cells

Kupffer cells

Microglia

27
Q

Macrophages appearance

A

Easily identified when they have visible ingested material in their cytoplasm

They look like dirty amoebas with an indented or kidney-shaped nucleus. Numerous lysosomes are present in their cytoplasm

28
Q

Function of macrophages

A

Phagocytosis of invaders (bacteria), removal of debris, and a number of other immune functions including presentation of antigens to lymphocytes

29
Q

Macrophages can fuse to form

A

A large cell with up to 100 nuclei. These multinucleated foreign body giant cells are capable of walling off relatively large masses of foreign material like splinters

30
Q

Plasma Cells

A

Small round cells with basophilic cytoplasm (RER) and an eccentric nucleus

31
Q

Plasma cells secrete ______ and are derived from _______

A
Circulating antibodies (immunoglobulins)
B-lymphocytes
32
Q

Mast cells

A

The large, motile cell is often amoeboid in shape filled with secretory granules, obscuring the small round nucleus

33
Q

Mast cells secrete

A

Heparin, histamine, and leukotrienes

34
Q

The secretion of mast cell granules (degranulation) can affect the leakage of the ________________. This can result in ____________

A

Plasma into CT

Immediate hypersensitivity reactions, allergy, anaphylaxis

35
Q

Other cells present in the CT as well as in blood include

A

Monocytes, lymphocytes, neutrophils, eosinophils

36
Q

Mesenchyme

A

Embroyonic looks connective tissue
Star shaped cells, abundant ground substance, and very few fibers
Pluripotent and can differentiate into all the support tissues

37
Q

Mesenchyme is derived from _______

A

Mesoderm germ layer with the exception of mesenchyme in head & neck, where it is derived from ectoderm

38
Q

Wharton’s jelly

A

A gelatinous loose connective tissue present in the umbilical cord

39
Q

3 types of adult CT

A

Loose CT
Dense irregular CT
Dense regular CT

40
Q

Specialized CT

A

Adipose tissue
Elastic CT
Reticular CT

41
Q

Loose CT (areolar)

A

Loose CT contains a small number of poorly organized fibers

42
Q

Dense irregular CT

A

The tissue primarily contains large bundles of collagen fibers arranged in a haphazard irregular organization

Fibroblasts- the main cell type

Can resist stress in multiple directions ex. Dermis

43
Q

Dense regular CT

A

This tissue is filled with large bundles of collagen fibers arranged in parallel bundles, extending in the direction of tension

Ex. Tendons, ligaments, and cornea

44
Q

Adipose tissue is highly vascular, true or false?

A

True

Lipomas - the most common mesenchymal tumor in adults

45
Q

Elastic CT

A

Specialized type of dense regular CT in which the predominant type of fiber is elastic

Present in the vocal cords and in the tissue connecting adjacent vertebrae (ligamenta Flava)

46
Q

Reticular CT

A

CT framework or stroma of the lymphatic (lymph node, spleen) and hemopoietic tissues (bone marrow, spleen, liver)

It provides a delicate, flexible meshwork to support the cells