All MCAT Biology Resources
Example Questions
Example Question #1 : Other Muscle Concepts
Which of the following answer options is not a function of the sarcolemma?
Controls the tonic state of myocytes
Creates an ion potential across the muscle surface
Creates T-tubules from invaginations along the membrane
Allows attachment sites for communication hormones
Controls the iron levels of cardiac tissue
Controls the iron levels of cardiac tissue
The sarcolemma is the specialized cell membrane of a myocyte, or muscle cell. It performs all of the functions of a non-specialized plasmolemma, and forms T-tubules, which are important for muscle contraction.
Example Question #81 : Muscles And Myocytes
Which is not a function of muscle tissue?
Peristalsis
Motion
Leverage
Locomotion
Thermoregulation
Leverage
The primary functions of muscle tissue are motion and locomotion (movement in relation to the body, and movement of the entire body). Muscle is also responsible for the shiver response, used in thermoregulation. Finally, smooth muscles move substances through the body in the process known as peristalsis.
Leverage is a function primarily accomplished by bone.
Example Question #287 : Biology
What type of muscle cell is quadrangular, and features intercalated disks and multiple nuclei?
Smooth muscle
Cardiac muscle
None of the other answers
Thick muscle
Skeletal muscle
None of the other answers
None of the answer options satisfy all of the criteria given in the question. Cardiac muscle cells have intercalated discs, but are mononucleate.
Example Question #1 : Bone
A doctor oberves a teenager who noticed that one of his legs is about two inches longer than the other. He also sees that the patient had broken one of his legs when he was 8 years old, but the patient's notes don't indicate which leg. What conclusion is the doctor likely to come to?
The patient broke the shorter leg on the epiphyseal plate.
The patient broke the longer leg on the periosteum.
The patient broke the shorter leg on the diaphysis.
The patient broke the longer leg in the diaphysis.
The patient broke the longer leg on the epiphyseal plate.
The patient broke the shorter leg on the epiphyseal plate.
The epiphyseal plate is the site of longitudinal growth in bones. The patient likely broke the leg along the plate, which caused it to grow less than the other leg.
Example Question #1 : Bone
A fetal rat's femoral cartilage is injected with a marker prior to endochondral ossification. The marker becomes deactivated as the cartilage is converted to bone. In which part of the femur would we expect to see a high concentration of the marker once the rat reaches adulthood?
In the spongy bone of the diaphysis
Within the medullary cavity
On the articular surface of the bone
In the compact bone of the diaphysis
On the articular surface of the bone
The first important concept to understand for this question is the process of endochondral ossification. In this process, cartilage is converted into bone during the early life of an organism. Since the question specifies that the rat has reached adulthood, it must refer to the parts of the final bone product that remain as cartilage once endochondral ossification is complete.
Spongy bone and compact bone in the diaphysis have already ossified, and the medullary cavity contains bone marrow and adipose. To find cartilage in any of these regions would indicate a developmental abnormality.
The ends of bones that are in contact with other bones are protected from frictional damage by articular cartilage. Articular cartilage is essential to maintaining healthy joint function. Deterioration of this cartilage results in arthritis, or inflammation in the joints.
Example Question #281 : Systems Biology And Tissue Types
Which of the following is true relating cartilage to the skeletal system?
Cartilage is an intermediate that is stiffer than muscle, but softer than bone
Cartilage is not found in joints and vertebral discs
Cartilage has the ability to regenerate
There are two types of cartilage
Cartilage is produced via the breakdown of muscle and bone
Cartilage is an intermediate that is stiffer than muscle, but softer than bone
Cartilage is a flexible, avascular connective tissue. It is less flexible than muscle, but softer and more flexible than bone. These properties make it an ideal candidate for joints, providing a medium between the muscles and bones that enact forces on the joint. Cartilage is found on the epiphyses of long bones and between certain bones, such as vertebrae, to cushion the motion of the joints.
Due to its avascular nature, cartilage does not easily regenerate. It is formed by chondroblasts (cartilage cells) in a chondrin matrix. In endochondral ossification, cartilage can be used as a precursor to bone, but will never be formed as a result of bone breakdown. Finally, there are three types of cartilage: elastic cartilage, hyaline cartilage, and fibrous cartilage.
Example Question #3 : Bone
The diaphysis is able to grow in length because of thin layers of cartilage cells located in which of the following regions?
Periosteum
Medullary cavity
Marrow
Epiphyseal plate
Haversian canal
Epiphyseal plate
Thin layers of cartilage cells in the epiphyseal plate enable the diaphysis (bone shaft) to grow in length. The epiphyseal line forms when growth stops and ossification occurs, permanently fusing the diaphysis and epiphysis.
The periosteum is a tough connective tissue sheath that covers the outer surface of bones. The medullary cavity is a hollow cylinder inside the diaphysis. The medullary cavity contains bone marrow, which contains blood cells in different stages of development. The Haversian canals perforate bony structure and contain blood vessels, lymph vessels, and nerves.
Example Question #1 : Bone
What type of bone cell is responsible for resorbing bone tissue?
Osteocytes
Lacunae
Cartilage
Osteoblasts
Osteoclasts
Osteoclasts
Osteoclasts are bone cells that are responsible for resorbing—or breaking down—bone tissue. Osteoblasts, on the other hand, deposit bone tissue.
Cartilage is not a type of bone cell at all; it is a type of connective tissue consisting of chondrocytes suspended in an avascular matrix. Lacunae are small cavities within the bone matrix that house osteocytes; osteocytes are mature bone cells.
Example Question #2 : Bone
How do bones maintain a functional weight as they grow?
Osteocytes form long fibers around the medullary cavity
Osteoclasts lining the medullary cavity remove interior layers of matrix
Osteocytes create new Haversian systems to limit the bone weight
Osteoblasts secrete acidic compounds, which dissolve some of the adjoining matrix
Osteoblasts creates new lacuna to surround bone cells
Osteoclasts lining the medullary cavity remove interior layers of matrix
Osteoclasts dissolve bony matrix and repatriate calcium as the bone grows. This expands the meduallary cavity and maintains a manageable mass for the bones, while allowing the body to recycle valuable calcium deposits.
Example Question #5 : Bone Development And Growth
Where are osteocytes located?
The lacunae of Haversian systems
Beneath the periosteum
Surrounding the growth plates
Throughout the hydroxyapatite matrix
The lining of the medullary cavity
The lacunae of Haversian systems
Osteoytes, the long-lived star-shaped cells found in established bones, are primarily found within Haversian systems—the target-shaped tubes of bone matrix. They are encased in a bubble of interstitial fluid known as a lacuna.
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