BIO 140 Human Biology I - Questions and Solutions

1. Connective tissue is made of which three essential components?

1. cells, ground substance, and carbohydrate fibers
2. cells, ground substance, and protein fibers
3. collagen, ground substance, and protein fibers
4. matrix, ground substance, and fluid

2. Under the microscope, a tissue specimen shows cells located in spaces scattered in a transparent background. This is probably ________.

1. loose connective tissue
2. a tendon
3. bone
4. hyaline cartilage

3. Which connective tissue specializes in storage of fat?

1. tendon
2. adipose tissue
3. reticular tissue
4. dense connective tissue

4. Ligaments connect bones together and withstand a lot of stress. What type of connective tissue should you expect ligaments to contain?

1. areolar tissue
2. adipose tissue
3. dense regular connective tissue
4. dense irregular connective tissue

5. In adults, new connective tissue cells originate from the ________.

1. mesoderm
2. mesenchyme
3. ectoderm
4. endoderm

6. In bone, the main cells are ________.

1. fibroblasts
2. chondrocytes
3. lymphocytes
4. osteocytes

1. One of the main functions of connective tissue is to integrate organs and organ systems in the body. Discuss how blood fulfills this role.

Solution: Blood is a fluid connective tissue, a variety of specialized cells that circulate in a watery fluid containing salts, nutrients, and dissolved proteins in a liquid extracellular matrix. Blood contains formed elements derived from bone marrow. Erythrocytes, or red blood cells, transport the gases oxygen and carbon dioxide. Leukocytes, or white blood cells, are responsible for the defense of the organism against potentially harmful microorganisms or molecules. Platelets are cell fragments involved in blood clotting. Some cells have the ability to cross the endothelial layer that lines vessels and enter adjacent tissues. Nutrients, salts, and waste are dissolved in the liquid matrix and transported through the body.

2. Why does an injury to cartilage, especially hyaline cartilage, heal much more slowly than a bone fracture?

Solution: A layer of dense irregular connective tissue covers cartilage. No blood vessels supply cartilage tissue. Injuries to cartilage heal very slowly because cells and nutrients needed for repair diffuse slowly to the injury site.