MCAT Biology : Connective Tissue and Epithelium

Study concepts, example questions & explanations for MCAT Biology

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Example Questions

Example Question #11 : Epithelial Tissue And Integumentary System

Which term refers to the top layers of cells in the epidermis?

Possible Answers:

Subcutaneous layer

Stratum corneum

Sebaceous layer

Stratum germinativum

Dermis

Correct answer:

Stratum corneum

Explanation:

The stratum corneum encompasses the very top two layers of cells in the epidermis. It consists almost entirely of dead, keratinzed skin cells that have been pushed to the outermost layer. The stratum corneum forms a protective, waterproof barrier against the outside environment.

Example Question #12 : Epithelial Tissue And Integumentary System

The parietal cells of the stomach are vital for both food digestion and as a defense mechanism against pathogens. When the parietal cells are not functioning properly, diseases such sepsis due to Clostridium difficile and malnutrition may occur. To keep the digestive system healthy, proper nutrition as well as a balanced diet is vital.

The parietal cells of the stomach secrete hydrochloric acid via the hormone gastrin. Gastrin is released when the stomach distends, via the presence of proteins and/or indirectly by the vagus nerve from the parasympathetic nervous system. Hydrochloric acid breaks down certain ingested food as well as activates certain zymogens for further digestion of macromolecules. The high acidity of the stomach due to the release of hydrochloric acid by parietal cells also destroys most pathogens. When the parietal cell is not functioning properly, opportunistic pathogens may create health problems.

Parietal cells also secrete intrinsic factor, a glycoprotein which binds to vitamin B12 to prevent destruction of the vitamin by the hydrochloric acid. Down the gastrointestinal tract, the vitamin is absorbed by the ileum of the small intestine. Vitamin B12 is essential for red blood cell production. A diet low in vitamin B12 may lead to anemia.

The prolonged use of aspirin will significantly decrease the production of bicarbonate in the mucosal layer of the stomach. How might this lead to a gastric ulcer?

Possible Answers:

The inability to neutralize the high acidity of the stomach leading to gastric ulcer.

Excess in ability to neutralize the high acidity of the stomach leading to gastric ulcer.

Aspirin promotes the production of prostaglandin leading to excess secretion of hydrochloric acid by the parietal cell. Excess hydrochloric acid secretion lead to gastric ulcer.

When the production of bicarbonate in the stomach is low, the body tries to maintain homeostasis by producing more hydrochloric acid by the parietal cell. Excess acid in the stomach will result in gastric ulcer.

Aspirin inhibits prostaglandins leading to excess secretion of hydrochloric acid by the parietal cell. Excess hydrochloric acid secretion lead to gastric ulcer.

Correct answer:

The inability to neutralize the high acidity of the stomach leading to gastric ulcer.

Explanation:

The stomach produces bicarbonate along the mucosal layer to neutralize the high acidity of the stomach. Without proper neutralization of the acid along the mucosal layer, the acid can directly destroy the barrier. When the acid destroys the mucosal layer, gastric ulcers may occur.  

Example Question #1 : Connective Tissue Types And Properties

Bone is primarily composed of which type of tissue?

Possible Answers:

Muscle tissue

Nervous tissue

Endothelial tissue

Connective tissue

Epithelial tissue

Correct answer:

Connective tissue

Explanation:

Bone is considered a connective tissue. The hydroxyapatite crystal forms a generous amount of extracellular matrix, helping to connect the cells of the bone. This large amount of extracellular material is a defining characteristic of connective tissue.

Nervous tissue carries electrical impulses through the body. Muscular tissue is involved in contraction. Epithelium lines the biological lumens and areas exposed to the external environment, including the tracts for respiration, digestion, and excretion. Endothelium lines the tracts that are fully contained in the body, namely the circulatory system and heart chambers.

Example Question #1 : Connective Tissue Types And Properties

Which of the following connective tissues serves to link bone to bone?

Possible Answers:

Ligament

Tendon

Adipose

Cartilage

Correct answer:

Ligament

Explanation:

Ligaments serve to link bone to bone, mainly playing a role in stability rather than force transduction. Once a tendon has pulled on the bone, ligaments provide a mechanism for nearby bones to follow, allowing for a smooth and coordinated movement.

Tendons link skeletal muscle to bone. Cartilage is the main tissue of the ears and nose, and generally provides structure or biological cushioning. Adipose is fat tissue, responsible for storing water and nutrients for extended periods.

Example Question #1 : Connective Tissue Types And Properties

Which of the following connective tissues serves to link skeletal muscle to bone?

Possible Answers:

Cartilage

Adipose

Ligament

Tendon

Correct answer:

Tendon

Explanation:

Tendons link skeletal muscle to bone. When skeletal muscle contracts and shortens, the tendon pulls the bone in the direction of the muscle contraction to propel movement.

Ligaments serve to link bone to bone, mainly playing a role in stability rather than force transduction. Cartilage is the main tissue of the ears and nose, and generally provides structure or biological cushioning. Adipose is fat tissue, responsible for storing water and nutrients for extended periods.

Example Question #1 : Connective Tissue Types And Properties

Which of the following is not an example of connective tissue?

Possible Answers:

Skin

Bone

Adipose

Blood

Correct answer:

Skin

Explanation:

Skin is composed of epithelial cells, and is therefore not an example of connective tissue. The major types of connective tissue include bone, adipose, blood, and cartilage. Connective tissue is responsible for binding and support of other tissue.

Any tissues can essentially be broken down into epithelium (or endothelium), muscle tissue, neural tissue, or connective tissue.

Example Question #1 : Connective Tissue Types And Properties

Which of the following is a type of connective tissue?

Possible Answers:

Nerves

Skin

Heart

Blood

Muscles

Correct answer:

Blood

Explanation:

Connective tissues are defined as cells suspended in an expansive extracellular matrix. For blood, plasma serves as the matrix that suspends erythrocytes. Other types of connective tissue include cartilage, bone, and adipose.

Any kind of muscle, nervous, or epithelial cell is in its own category, separate from connective tissue. Skin is a type of epithelium, and the heart is composed of cardiac muscle tissue.

Example Question #1 : Connective Tissue Types And Properties

In what parts of the adult human body would you be most likely to find chondrin?

Possible Answers:

Femoral diaphyses

The skull

The ears (pinna) or nose

Within haversian canals

Correct answer:

The ears (pinna) or nose

Explanation:

Chondrin is the elastic matrix found in cartilaginous connective tissue. In order to identify where chondrin can be found in the body, we should identify where in the body we would find cartilage.

The ears and nose are some of the few structures on the adult human body that contain cartilage. Other cartilage structures include the vertebral discs, public symphysis, menisci in the knees, and most sternocostal joints.

The human skull is formed by intramembranous ossification, a process in which mesenchymal stem cells form osteoblasts and eventually bone. Note that there is no cartilage involved in this process. Long bones, such as the femur, are formed by the process of endochondral ossification, in which cartilage is converted into bone. This process occurs long before adulthood, however, and would not be a reasonable answer in this case. Diaphyses of bones are composed of compact and spongy bone. Haversian canals house blood vessels, nerves, and lymph within bone.

Example Question #1 : Connective Tissue Types And Properties

What is the definition of tissue?    

Possible Answers:

Living cells suspended in a living or nonliving matrix

A group of cells suspended in a noncellular matrix

An organized collection of many types of cells

Cells that all perform a similar function

Cells that all display similar traits

Correct answer:

Living cells suspended in a living or nonliving matrix

Explanation:

Tissue, by definition, is made up of groups of similar cells. However, these cells may be suspended in a living, cellular matrix, or in a nonliving, noncellular matrix. For example, muscle tissue is composed of tightly packed cells in an organized matrix; however, blood is comprised of scattered cells in an aqueous plasma matrix. It is important to remember that all living components of the body are made entirely of tissue, so bone, blood, fat, etc. must fit the definiton of tissue.

Example Question #1 : Connective Tissue Types And Properties

What are the three types of cartilage?

Possible Answers:

Maxillary cartilage, formative cartilage, and elastic cartilage

Hyaline cartilage, juvenile cartilage, and maxillary cartilage

Fibrocartilage, rigid cartilage, and maxillary cartilage

Hyaline cartilage, rigid cartilage, and juvenile cartilage

Elastic cartilage, hyaline cartilage, and fibrocartilage

Correct answer:

Elastic cartilage, hyaline cartilage, and fibrocartilage

Explanation:

Hyaline cartilage is rigid, glassy in appearance, and provides cushioning for smooth joints. Fibrocartilage is fibrous and provides support in high-stress areas, such as the pubic symphysis. Elastic cartilage is flexible and makes up fleshy appendages, such as the nose and ears. 

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