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
Monocytes
Migrate from the blood into the CT, where they differentiate into a variety of cells including macrophages
26
Macrophages are called ______ in the lung, _______ in the liver. The macrophages of the CNS are called ________
Dust cells Kupffer cells Microglia
27
Macrophages appearance
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
Function of macrophages
Phagocytosis of invaders (bacteria), removal of debris, and a number of other immune functions including presentation of antigens to lymphocytes
29
Macrophages can fuse to form
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
Plasma Cells
Small round cells with basophilic cytoplasm (RER) and an eccentric nucleus
31
Plasma cells secrete ______ and are derived from _______
``` Circulating antibodies (immunoglobulins) B-lymphocytes ```
32
Mast cells
The large, motile cell is often amoeboid in shape filled with secretory granules, obscuring the small round nucleus
33
Mast cells secrete
Heparin, histamine, and leukotrienes
34
The secretion of mast cell granules (degranulation) can affect the leakage of the ________________. This can result in ____________
Plasma into CT Immediate hypersensitivity reactions, allergy, anaphylaxis
35
Other cells present in the CT as well as in blood include
Monocytes, lymphocytes, neutrophils, eosinophils
36
Mesenchyme
Embroyonic looks connective tissue Star shaped cells, abundant ground substance, and very few fibers Pluripotent and can differentiate into all the support tissues
37
Mesenchyme is derived from _______
Mesoderm germ layer with the exception of mesenchyme in head & neck, where it is derived from ectoderm
38
Wharton’s jelly
A gelatinous loose connective tissue present in the umbilical cord
39
3 types of adult CT
Loose CT Dense irregular CT Dense regular CT
40
Specialized CT
Adipose tissue Elastic CT Reticular CT
41
Loose CT (areolar)
Loose CT contains a small number of poorly organized fibers
42
Dense irregular CT
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
Dense regular CT
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
Adipose tissue is highly vascular, true or false?
True | Lipomas - the most common mesenchymal tumor in adults
45
Elastic CT
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
Reticular CT
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