Cellular Tissue Organisation

Soft connective tissue consists of cells embedded in what?

The volume of the matrix of soft connective tissue is greater than that which is occupied by cells.

What is responsible for the synthesis and secretion of extracellular matrix?

The cells and collagen fibres of the extracellular matrix are embedded in a gel formed by proteoglycans. What are proteoglycans?

What is the best description of the shape of a fibroblast?

What is the name given to the amorphous gel-like substance found in the extracellular space which contains all the components of the ECM apart from collagen and elastin fibres?

What is the name of the adhesive proteins in the extracellular matrix that cross-link cells to proteins via the cytoskeleton?

Fill in the blanks below to describe the strucure of the proteoglycans. Proteoglycans are long [blank_start]proteins[blank_end] with glycosaminoglycan polymers extending from them. Glycosaminoglycans are [blank_start]polysaccharides[blank_end] which are too stiff to fold into compact structures due to the [blank_start]repulsion[blank_end] of their subunits. This means that they adopt a highly [blank_start]extended[blank_end] shape. Proteoglycans have a high density of negative charge due to [blank_start]sulfate[blank_end] groups. These produce as osmotically active 'ion cloud' that readily attracts [blank_start]water[blank_end] to form gels. This gel creates [blank_start]turgor[blank_end] pressure that allows the extracellular matrix to withstand [blank_start]compression[blank_end].

The glycosaminoglycan is a polymer of repeating units of what?

Fill in the blanks below to describe the structure of collagen. Collagen molecules consist of [blank_start]3[blank_end] polypeptides wound in a [blank_start]triple[blank_end] helix. These helices become bundled and crosslinked into [blank_start]fibrils[blank_end] and then into [blank_start]fibres[blank_end].

Fibril-forming collagens are visible. Type [blank_start]I[blank_end] occurs in skin, tendon, bone and dentin and is resistant to [blank_start]tension[blank_end]. Type [blank_start]II[blank_end] occurs in cartilage and the vitreous of the eye. It is resistant to [blank_start]pressure[blank_end]. Type [blank_start]III[blank_end] occurs in skin, muscle, blood vessels, liver and provides structural framework and [blank_start]stability[blank_end].

Which type of collagen - a network-forming type collagen - is present in all basement membranes which serves to support cells and filter materials?

Which fibril-associated collagens with interrupted triple helices (FACITs) are associated with type I and type II fibrils which serve to bind fibrils together or bind fibrils to the ECM? Check all that apply.

Which type of collagen - an anchoring filament type collagen - occurs in the epithelial tissue and serves to link the epidermis to the basal lamina?

Sheet collagens form part of the underlying layer of the basement membrane. Like other collagens, they form a triple helix.

Which type of soft connective tissue is found in the embryo and bone marrow and is required for embryonic development as well as growth/repair?

Which type of soft connective tissue is required to maintain organ position by attaching epithelial tissue to underlying tissue?

Which type of soft connective tissue provides tensile strength through elastic fibres and is thus found in tendons, the dermis and organ capsules?

What type of soft connective tissue provides support for organs and is thus found in the lymphatic tissue, bone marrow and spleen?

Which type of soft connective tissue serves as a storage of fat as an energy source and shock absorber, occurring around the organs and in the breasts?

Fill in the blanks below to describe the structure of elastin. Elastic fibres consist of a network of microfibrils of [blank_start]fibrillin[blank_end] with a core of cross-linked elastin. Elastin forms [blank_start]low[blank_end] energy [blank_start]coiled[blank_end] protein structures with [blank_start]covalent[blank_end] linkages between neighbouring molecules. Under pressure, elastin stores energy as it [blank_start]stretches[blank_end]. It uses this stored energy to [blank_start]recoil[blank_end] and adopt its previous lower energy conformation when the pressure is released.

Elastin is continuously made throughout life.

Elastin is sensitive to damage from what?

What name is given to a type of cell that is produced in the same region in which it will perform its specialised function?

What name is given to a type of cell that moves to a region in response to a bodily condition, for example the leukocytes?

Mast cells are examples of [blank_start]progenitor[blank_end] cells. These are similar to stem cells but are more specific - they have the tendency to differentiate into a certain cell type instead of any cell. They remain in the [blank_start]connective tissue[blank_end] permanently and rapidly [blank_start]divide[blank_end] to replace themselves.