Connective Tissue

Question 1

Which embryonic germ layer is Connective Tissue derived from

Answer 1

Mesoderm

Question 2

Functions of connective tissue (5)

Answer 2

-structural framework
-protection
-energy stores
-transport of nutrients
-defense from pathogens

Question 3

Connective tissue consists of (2)

Answer 3

-cells
-matrix (protein fibres and fluid ground substance)

Question 4

The matrix is (3)

Answer 4

-everything but the cells
-majority of volume
-fibres and ground substance

Question 5

Three categories of connective tissue

Answer 5

-connective tissue proper (loose and dense)
-supportive connective tissue (cartilage and bone)
-fluid connective tissue (blood and lymph)

Question 6

Tendons connect

Answer 6

Muscle to bone

Question 7

Ligaments connect

Answer 7

Bone to bone

Question 8

Connective Tissue Proper is composed of (3)

Answer 8

-cells (fixed or migratory)
-fibres (collagen, reticular, elastic)
-ground substance

Question 9

Fixed cells include (4) and their main purpose is (3)

Answer 9

-Fibroblasts
-Adipocytes
-Mesenchymal Stromal Cells (stem cells)
-Macrophages
—>local maintenance, repair, and energy storage

Question 10

Migratory cells include (6) and their purpose is to ____

Answer 10

-mast cells
-lymphocytes
-monocytes
-eosinophils
-neutrophils
-plasma cells
—>aggregate to defend against invading pathogens and repair damaged tissue

Question 11

Three main types of fibre

Answer 11

-collagen
-reticular
-elastic

Question 12

Collagen Fibres (4)

Answer 12

-long, straight, flexible, strong
-stain pink with eosin
-most common fibre in connective tissue proper
-tendons and ligaments

Question 13

Reticular Fibres (4)

Answer 13

-same protein as collagen but thinnner
-need a special silver stain to see
-tough, flexible, branching/interwoven network (called Stroma)
-found in parenchyma of spleen, liver, lymph nodes, glands, and bone marrow

Question 14

Elastic Fibres (6)

Answer 14

-composed of the protein Elastin
-branch and wavy
-stretch and recoil in a relaxed state
-organized into discontinuous sheets
-can only see with specialized stain
-found in internal and external elastic laminate of arteries and arterioles (helps maintain blood pressure)

Question 15

Ground Substance (3)

Answer 15

-surrounds the cells and fibres of connective tissue proper
-clear and viscous (slows passage of pathogens and facilitates phagocytosis)
-contains proteoglycans and glycoproteins

Question 16

Fibroblasts (6)

Answer 16

-most abundant type of fixed cell
-ONLY cells that are ALWAYS present
-involved in wound healing
-nucleus is oval shaped and centrally placed
-elongated, process lie along fibres
-secrete protein subunits that form the various fibres

Question 17

Mesenchymal Stem/Stromal Cells (MSCs) (5)

Answer 17

-smaller and less differentiated than fibroblasts
-stellate (star) or fusiform (spindle) shape
-oval nucleus with a prominent nucleolus
-along capillaries
-multipotent

Question 18

Which is the precursor cell from which other connective tissue tissue cells develop?

Answer 18

Mesenchymal Stem/Stromal Cells (MSCs)

Question 19

Adipocytes (Adipose Cells) (6)

Answer 19

-involved in lipid storage
-fixed cell of connective tissue proper
-main cell type in adipose tissue
-present in loose connective tissue
-contain one or more lipid droplets
-nucleus is displaced peripherally, cytoplasm is very narrow

Question 20

Macrophages (Histiocytes) (6)

Answer 20

-lie along fibres
-stellate (star) or fusiform (spindle) shape
-large, irregularly shaped nucleus
-can be difficult to distinguish from fibroblasts
-function is to phagocytose dead tissue and foreign material + activate immune system
-store antigenic material which is presented to antibody producing cells

Question 21

With the exception of ____, migratory cells of connective tissue proper are immigrants from the blood

Answer 21

Mast cells

Question 22

Define Amoeboid and provide 4 examples

Answer 22

Cells that can pass between endothelial cells of vessels to enter tissue (lymphocytes, monocytes, eosinophils, neutrophils)

Question 23

Plasma cells differentiate from ____

Answer 23

Lymphocytes

Question 24

Mast Cells (4)

Answer 24

-large cells, shape varies between species
-small, round nucleus
-basophilic granules contain Heparin and Histamine (released in response to injury and infection)
-can form tumours / produce overactive allergic reactions

Question 25

Plasma Cells (4)

Answer 25

-ovoid, basophilic cytoplasm -“cartwheel” pattern nucleus -high numbers present in lymph nodes and connective tissue of digestive tract -produce antibodies

Question 26

Loose (Areolar) Connective Tissue (8)

Answer 26

-the least specialized connective tissue -binds cells/structures but allows movement -mostly composed of ground substance (shock absorption and inhibition of microorganisms from entering) -loosely arrange fibres -cells resist infection and assist wound healing -fixed and migratory cells -highly vascular -form packing around organs and supports epithelial

Question 27

Dense Connective tissue can be

Answer 27

Regular or Irregular

Question 28

Dense Connective Tissue (3)

Answer 28

-high strength, few nerves and blood vessels -collagen fibres abundantly present -can be regular or irregular based on collagen fibre arrangement

Question 29

If collagen fibres run parallel, the tissue is

Answer 29

Regular Dense Connective Tissue

Question 30

Examples of Regular Dense Connective Tissue (3)

Answer 30

-tendons -ligaments -joint capsules

Question 31

If collagen fibres are randomly arranged, the tissue is called

Answer 31

Irregular Dense Connective Tissue

Question 32

Two examples of Irregular Dense Connective Tissue are

Answer 32

-dermis -organ capsules

Question 33

Elastic Connective Tissue (4)

Answer 33

-mainly made of elastic fibres -can be irregularly or regularly arranged -high elasticity, moderate strength -airways of respiratory tree, arteries, ligaments of abdominal cavities, and vertebral column

Question 34

Reticular Connective Tissue (2)

Answer 34

-forms the fibrous framework/support of soft tissues -spleen, liver, lymph nodes, and bone marrow

Question 35

Adipose Tissue can be

Answer 35

-white -brown

Question 36

Adipose Tissue (4)

Answer 36

-mostly Adipocytes (fat cells) -storage of energy and water -provides padding, packaging, and insulation -can be white or brown

Question 37

Which type of adipose tissue would be found in young animal and hibernators?

Answer 37

Brown Adipose Tissue

Question 38

White Adipose Tissue (3)

Answer 38

-makes up the bulk of body fat -cells are large and unilocular -peripheral nuclei with a rim of cytoplasm

Question 39

Brown Adipose Tissue (5)

Answer 39

-small, multilocular cells -nuclei is round and centrally placed -involved in heat production (especially in young animals and hibernators) -contains mainly capillaries and nerves -colour due to cytochrome respiratory pigment (mitochondria)

Question 40

Lipoma (7)

Answer 40

-a benign neoplasm composed of Adipocytes -very common in dogs -common in budgies and gallahs -rare in cats -can feel soft or moderate firm -can grow to a significant size -removed surgically