Connective Tissue Proper (Part 2 of 3)

Question 1

Name the primary germ layer that connective tissue is derived from?

Answer 1

Mesoderm

Question 2

Describe the basic components of connective tissue?

Answer 2

Protein Fibres:
- Strengthen & support the tissue.
- 3 types: collagen fibres, elastic fibres, reticular fibres.

Cells:
- Scattered throughout the tissue.

Ground Substance:
- The material that suspends the connective tissue cells and protein Fibres (aka cytoplasm).
- Can be fluid, semisolid, or solid.
- Mainly composed of protein and carbohydrate & varying amounts of water.

Question 3

Describe the functions of connective tissue? (1)

(PBS STI)

Answer 3

Physical Protection:
- Connective tissue surrounds and therefore protects the organs of the body.
- Example: fat around the kidneys provides a cushion to protect them from injury.

Binding:
Connective tissue binds other tissues together.
- Ligaments connect bone to bone.

Support:
- Provides the framework for organs and other structures of the body.
- Example: Connective tissue forms capsules surrounding organs such as the spleen.

Question 4

Describe the functions of connective tissue? (2)

(PBS STI)

Answer 4

Storage:
- Fat = major form of energy storage.
- Bone = stores minerals such as calcium and phosphorus.

Transport:
- Blood transports different substances (eg gases, hormones, nutrients and waste products around the body).

Immune Protection:
- Some leukocytes (or WBC) can leave the bloodstream and enter the surrounding connective tissue to fight infection.

Question 5

Name the five types of connective tissue and classify them as either connective tissue proper or specialised connective tissue?

Answer 5

Question 6

Label this diagram of cells in connective tissue proper?

Answer 6

Question 7

Label this diagram of protein fibres in connective tissue proper?

Answer 7

Question 8

Describe the structure, function and location of the areolar (loose) connective tissue?

Answer 8

Structure:
1. Contains all connective tissue cell and protein fibre types.

Function:
1. Support, protect and bind other tissues and structure in the body.

Location:
1. Dermis layer of the skin.
2. Subcutaneous layer underneath the skin and surrounding organs, blood vessels, nerves and other structures.

Question 9

Describe the structure, function and location of the adipose (loose) connective tissue?

Answer 9

Structure:
1. Composed of adipocytes (aka fat cells), which are tightly packed within the viscous ground substance.

Function:
1. Store energy, provide cushioning, and shock absorption for organs.
2. Act as an insulator to minimize heat loss.

Location:
1. Found in the subcutaneous layer underneath the skin and surrounding organs such as the kidneys.

Question 10

Describe the structure, function and location of the reticular (loose) connective tissue?

Answer 10

Structure:
1. Network of reticular fibres.
2. Scattered fibroblasts and leukocytes within the viscous ground substance.

Function:
1. Mesh-like arrangement of reticular fibres = form the framework of organs, which is called stroma.

Location:
1. Forming the stroma of the liver, spleen, thymus, and lymph nodes.

Question 11

Describe the structure, function and location of the dense regular connective tissue? DENSE

Answer 11

Structure:
1. Tightly packed collagen fibres arranged in parallel bundles.
2. Fibroblasts are arranged in rows in between the parallel bundles.

Function:
1. Bind other structures together.
2. Capable of resisting stress in one direction (bundles of collagen fibres are aligned in the direction in which forces are applied).

Location:
1. Found in ligaments (connect bone to bone).
2. Found in tendons (connect muscle to bone).

Question 12

Describe the structure, function and location of the dense irregular connective tissue? DENSE

Answer 12

Structure:
1. Tightly packed collagen fibres arranged in bundles that are aligned in different directions.
2. Fibroblasts scattered in the spaces between these bundles.

Function:
1. Capable of resisting stress in multiple directions (due to the random alignment of the collagen bundles).
2. Protect other tissues and organs from forces applied to them in multiple directions.

Location:
1. Dermis of the skin.
2. In the periosteum and perichondrium (the connective tissue coverings of bone and cartilage.
3. In the capsules of organs such as the liver, kidney and spleen.

Question 13

Describe the structure, function and location of the elastic connective tissue? DENSE

Answer 13

Structure:
1. Primarily composed of elastic fibres, with fibroblasts scattered in the spaces between the fibres.

Function:
1. Abundance of elastic fibres = allows structures to stretch and then recoil back to their original shape.

Location:
1. Walls of elastic arteries.
2. Parts of the respiratory tract (trachea and bronchi).
3. Vocal cords.
4. Some ligaments.

Question 14

What is the main difference between loose connective tissue and dense connective tissue?

Answer 14

Loose connective tissue has a relatively lower proportion of cells and protein fibres and a relatively higher proportion of ground substance than dense connective tissue.

Question 15

Label this diagram of cells in connective tissue proper?

Answer 15

Question 16

What are the 2 categories that cells can be divided in and what are their location and primary function.

Answer 16

Resident cells:
- Location = fixed within the connective tissue.
- Function = supporting and maintaining the extracellular environment.

Wandering cells:
- Location = move throughout the connective tissue.
- Function = immune protection and tissue repair.

Question 17

Describe the structure and function of the 2 resident cells in connective tissue proper?

Answer 17

Fibroblasts:
Structure = large, flat cells with tapered ends and a flattened, centrally located nucleus.
Function = producing the protein fibres and ground substance (i.e. extracellular matrix).

Adipocytes:
Structure = large cells containing a central lipid droplet.
Function = Lipid droplet –> pushes the nucleus to the periphery of the cell.

Question 18

Describe the structure and function of the 4 wandering cells in connective tissue proper?

MC
PC

Answer 18

Mast Cells:
Structure = small cells with a granule-filled cytoplasm.
Function = inflammatory response by releasing…
1. Heparin to prevent blood clotting.
2. Histamine to dilate blood vessels = increased blood flow.

Plasma Cells (B-lymphocytes):
Function = produce antibodies (a protein) that fight specific antigens, or foreign bodies that induce an immune system.

Question 19

Describe the function of the 4 wandering cells in connective tissue proper?

M
OL

Answer 19

Macrophages (monocyte):
Function = engulfs anything that is foreign or damaged (phagocytic).

Other leukocytes (mainly neutrophils):
Function = respond to bacterial infection by engulfing the bacteria causing the infection (phagocytic).

Question 20

Describe the 3 protein fibres in connective tissue?

Answer 20

Structure:

Collagen = forms long, cable-like fibres that are strong and flexible.

Elastic = thin fibres that contain the protein elastin, making them stretchy and capable of recoiling.

Reticular = thin, delicate fibres & intertwine to form strong, flexible networks.