MCAT Biology : MCAT Biological Sciences

Study concepts, example questions & explanations for MCAT Biology

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Example Questions

Example Question #2 : Connective Tissue Types And Properties

Which of the following is a type of connective tissue?

Possible Answers:

Heart

Blood

Nerves

Muscles

Skin

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 #2 : Connective Tissue Types And Properties

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

Possible Answers:

The ears (pinna) or nose

Within haversian canals

The skull

Femoral diaphyses

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 #3 : Connective Tissue Types And Properties

What is the definition of tissue?    

Possible Answers:

An organized collection of many types of cells

A group of cells suspended in a noncellular matrix

Cells that all perform a similar function

Living cells suspended in a living or nonliving matrix

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 #814 : Mcat Biological Sciences

What are the three types of cartilage?

Possible Answers:

Fibrocartilage, rigid cartilage, and maxillary cartilage

Hyaline cartilage, rigid cartilage, and juvenile cartilage

Elastic cartilage, hyaline cartilage, and fibrocartilage

Maxillary cartilage, formative cartilage, and elastic cartilage

Hyaline cartilage, juvenile cartilage, and maxillary cartilage

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. 

Example Question #21 : Connective Tissue And Epithelium

What is the means by which organisms maintain a constant internal environment in spite of fluctuations in the external environment?    

Possible Answers:

Homeostasis

Geriatrics

Physiology

Homeopathy

Reflexology

Correct answer:

Homeostasis

Explanation:

Homeostasis, or "steady-state" physiology, is the system of feedback loops that enables an organism to create a stable, adaptive environment. For example, the pancreas and the brain together work to regulate the blood sugar levels via the hormones insulin and glucagon.

Example Question #22 : Connective Tissue And Epithelium

What are the four types of tissue?   

Possible Answers:

Muscular, cardiac, nervous, sensory

Sensory, connective, nervous, dermal

Muscular, dermal, gastric, epithelial

Muscular, connective, nervous, epithelial

Cardiac, connective, sensory, epithelial

Correct answer:

Muscular, connective, nervous, epithelial

Explanation:

The four types of tissue are muscular, connective, nervous, and epithelial.

Muscular tissue encompasses skeletal, cardiac, and smooth muscle. Nervous tissue creates the central and peripheral nervous systems (CNS, PNS) and consists of all neurons and glial cells. Epithelial tissue makes up "borders" and lines most organs. Connective tissue generally fills spaces and provides the suspensory matrices for the body, such as bone, fat, blood, and cartilage.

Example Question #811 : Mcat Biological Sciences

Which of the following is an example of an immovable joint?

Possible Answers:

Skull sutures

Phalanges

Tarsal joints

Pubic symphysis

Sacrailium

Correct answer:

Skull sutures

Explanation:

Immovable joints are fused shortly after birth, so that they are no longer functional for articulation. The bones of the skull remain open, joined with strips of cartilage, until an infant has passed through the birth canal. They stay open for a short period, giving the baby's brain room to grow. After the brain has finished its major growth stages, the bones of the skull knit together, forming a protective barrier.

Example Question #792 : Biology

Tendons connect which two structures?

Possible Answers:

Joint and bone

Muscle and muscle

Bone and bone

Muscle and bone

Fat and fascia

Correct answer:

Muscle and bone

Explanation:

Tendons connect muscles to bones, allowing for the muscle contraction to affect the bone and result in articulation. Tendons are essential to provide articulation and leverage points to for motion and locomotion.

Example Question #812 : Mcat Biological Sciences

Cartilage repair is slower than that of other connective tissues because __________.

Possible Answers:

chondrocytes have a larger surface area than cells of other connective tissues

cartilage contains a higher denisty of blood vessels than other connective tissue

chondrocytes are supplied by diffusion

chondrocytes produce a large amount of collagen

Correct answer:

chondrocytes are supplied by diffusion

Explanation:

Cartilage does not contain blood vessels. Chondrocytes, the specialized cells of cartilage, are supplied by diffusion, which slows growth and repair. While they do produce collagen, this is not the direct reason for the relatively slow growth of cartilage.

Example Question #21 : Connective Tissue And Epithelium

Passage:

In a fictional universe, a new life form is discovered that appears to have a number of similarities to humans. Since its discovery by humans, it has been studied with x-ray imaging, magnetic resonance imaging (MRI), computed tomography imaging (CT), as well as with blood chemistries and laboratory studies. Based upon such analyses, scientists have found that both structurally and functionally, this fictional species, called Lorempis marengis, is highly similar to humans. It has structures that appear similar to lungs that are active during respiration. It has a structure that is highly active at all times, especially so in different parts during different activities (similar to the human brain). It also appears to have a digestive tract with a mouth, esophagus, stomach, small intestine, large intestine, and anus that is assumed to carry out the same functions at the cellular level as the parts of the human digestive tract. Scientists are now hoping to continue studying the organism at the cellular level to confirm their assumption that the cellular functions are indeed similar to those of human tissues.

If we assume that the muscle types and cells present in Lorempis marengis are the same, structurally and functionally, as those found in humans, which of the following muscle types best describes the type of muscle cell that lines the walls of most blood vessels?

Possible Answers:

Smooth muscle

Striated muscle

Skeletal muscle

Biceps muscle

Cardiac muscle

Correct answer:

Smooth muscle

Explanation:

The type of muscle that lines the walls of most blood vessels in the human body is smooth muscle. We are told to make the assumption that the muscle types and cells present in Lorempis marengis are the same, structurally and functionally, as those found in humans. Therefore, the type of muscle that lines the walls of most blood vessels in Lorempis marengis is also smooth muscle.  Blood vessels contain a specific subtype of smooth muscle, called vascular smooth muscle, that helps to regulate the distribution of blood volume throughout the entire body by either appropriately contracting or relaxing to restrict or increase blood flow to various parts of the body to best meet bodily needs (typically oxygen delivery).

Skeletal muscle cells, also known as striated muscles, are the type of muscle cells that make up the larger, weight-bearing muscles of the body. These are not the type of muscle cells that are found within the walls of blood vessels. The biceps muscles are the muscles responsible for flexion of the forearm at the elbow. They are not a type of muscle cell, per se, and they are made up of skeletal muscle cells. 

Cardiac muscle cells are the type of muscle cells that make up the myocardium, or muscle cells of the heart. These are not the type of muscle cells that are found within the walls of blood vessels.

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