Bio 2113 Test 2 -- Practice Test A

The differences in skin color among human races are primarily due to the amount of melanin produced by melanocytes. Melanin is a pigment that gives color to the skin, hair, and eyes. Melanocytes are cells that produce melanin. The more melanin produced, the darker the skin color. Therefore, variations in the amount of melanin produced by melanocytes account for the different skin colors observed among human races.

Epithelial tissue is a type of tissue that covers the surfaces of organs, lines cavities, and forms glands. It is characterized by tightly packed cells that are arranged in continuous sheets. Epithelial tissue is also known for its ability to regenerate and repair itself. However, it does not contain blood vessels. This is because epithelial cells rely on diffusion for nutrient exchange and waste removal, and blood vessels would interfere with this process. Therefore, the absence of blood vessels is a characteristic of epithelial tissue.

Skeletal muscle tissue is characterized as striated and voluntary. Striated refers to the presence of alternating light and dark bands in the muscle fibers, giving it a striped appearance. Voluntary means that this type of muscle tissue is under conscious control, allowing us to move our body voluntarily. Therefore, skeletal muscle is the correct answer as it possesses both of these characteristics. Visceral muscle is smooth and involuntary, while cardiac muscle is striated but involuntary.

The sacrum, a triangular bone at the base of the spine, forms a joint with the coccyx, also known as the tailbone. The sacrum and coccyx are part of the vertebral column and are located at the inferior end of the spine. This joint allows for slight movement and flexibility in the lower back and pelvis region. The sacrum does not form a joint with the pelvis, femur, or L5 (the fifth lumbar vertebra).

Melanin is the substance that protects you from ultraviolet light. Melanin is a pigment produced by specialized cells called melanocytes, which are located in the skin, hair, and eyes. When the skin is exposed to sunlight, melanocytes produce more melanin to absorb and scatter the harmful ultraviolet (UV) radiation. This helps to prevent damage to the DNA in skin cells and reduces the risk of sunburn, skin cancer, and other harmful effects of UV radiation.

Desmosomes are specialized structures found in the epidermis that play a crucial role in joining keratinocytes together. They act as strong adhesive connections between adjacent cells, providing structural support and stability to the epidermis. This helps to maintain the integrity of the skin and prevents the cells from separating under mechanical stress. Desmosomes contribute to the overall strength and cohesion of the epidermis, ensuring its protective function.

The distal epiphysis of the humerus forms a joint with the radius and ulna. The humerus is the bone located in the upper arm, and its distal epiphysis refers to the end of the bone that is closest to the hand. The radius and ulna are the two bones located in the forearm, and they articulate with the distal epiphysis of the humerus to form the elbow joint. This joint allows for movements such as flexion and extension of the forearm.

A fracture of the zygomatic bone would be most likely in this case because the zygomatic bone, also known as the cheekbone, is the bone that forms the prominence of the cheek. Since Johnny broke his "cheek bone," it suggests that the fracture occurred in the zygomatic bone. The other options, such as the vomer, mandible, and lacrimal bone, are not directly related to the cheek area.

Bone marrow is not primarily made up of collagen. It is a soft, spongy tissue found in the center of bones that is responsible for producing blood cells. While it does contain some collagen, it is mainly composed of hematopoietic stem cells, fat cells, and blood vessels. Collagen, on the other hand, is a fibrous protein that provides strength and structure to various tissues in the body, such as ligaments, tendons, and periosteum.

The cuboid bone is found in the foot. It is one of the seven tarsal bones, which are located in the midfoot region. The cuboid bone is situated on the lateral side of the foot, between the calcaneus (heel bone) and the fourth and fifth metatarsal bones. It helps to provide stability and support to the foot, allowing for proper movement and weight-bearing.

The hyoid bone is the only bone listed that is not part of the skull. It is a U-shaped bone located in the neck, just below the mandible. The zygomatic, frontal, and sphenoid bones are all part of the skull. Therefore, the hyoid bone is inferior to all of the others in terms of its anatomical position.

The reproducing cells of the epidermis are found in the stratum basale layer of the skin. This layer is also known as the basal cell layer and is located at the bottom of the epidermis. It is responsible for producing new skin cells through a process called mitosis. These new cells then migrate upwards to the upper layers of the epidermis, where they eventually become the outermost layer of the skin.

Based on the description provided, the presence of collagen fibers running in various directions indicates that the tissue is part of the dermis. The dermis is composed of two layers: the papillary layer and the reticular layer. The papillary layer is closer to the epidermis and contains loosely arranged collagen fibers, while the reticular layer is deeper and consists of dense irregular connective tissue with collagen fibers running in different directions. Therefore, the presence of collagen fibers in multiple orientations suggests that the tissue is located in the reticular layer of the dermis.

The proximal end of the tibia forms a joint with the femur. The tibia is one of the two bones in the lower leg, and its proximal end refers to the upper part of the bone. The joint formed between the tibia and the femur is known as the knee joint. This joint allows for movement and stability of the leg, and is crucial for activities such as walking, running, and jumping. The talus and calcaneus are bones in the foot, while the pelvis is a bone in the hip region, and they do not form a joint with the proximal end of the tibia.

Hematoma formation is the first step in bone repair. When a bone is fractured, blood vessels are also damaged, causing bleeding in the area. This leads to the formation of a blood clot or hematoma, which serves as a framework for the subsequent repair process. The hematoma provides a source of nutrients and immune cells that help clean up the damaged tissue and initiate the healing process.

The lateral end of the clavicle forms a joint with the scapula. This joint is known as the acromioclavicular joint and is located at the top of the shoulder. The clavicle connects to the scapula at the acromion process, allowing for movement and stability in the shoulder joint. The sternum, humerus, and 1st rib do not form a joint with the lateral end of the clavicle.

The pseudostratified epithelium and connective tissue of the trachea would be an example of a mucus membrane. Mucus membranes line various body cavities and organs that open to the exterior, such as the respiratory tract. The trachea is part of the respiratory system and its inner lining is composed of pseudostratified epithelium, which contains goblet cells that secrete mucus. The mucus helps to trap and remove foreign particles and pathogens from the airways, protecting the lungs. The connective tissue supports and nourishes the epithelial layer.

Holocrine sebaceous glands are responsible for producing sebum, an oily substance that lubricates the skin and hair. When these glands become clogged with excess sebum, bacteria can multiply, leading to inflammation and the formation of acne. This is why holocrine sebaceous glands are associated with acne.

If you are answered radius, you are not in anatomical position!

When it is 25 degrees F outside, the body would expect vasoconstriction of blood vessels to occur. Vasoconstriction is the narrowing of blood vessels, which helps to reduce blood flow to the skin and conserve heat. This is a physiological response that helps to maintain the body's core temperature in cold conditions. Vasodilation of blood vessels in the skin and increased secretion from sudoriferous glands are more likely to occur in warmer temperatures as the body tries to cool down. Therefore, vasoconstriction of blood vessels is the expected response in this situation.

The proximal phalanx is the bone located most distal. Distal refers to a position that is farther away from the center of the body or a point of reference. In this case, the proximal phalanx is the bone in the finger that is farthest away from the hand, making it the most distal bone among the options given.

The given tissue is called stratified squamous tissue because it has multiple layers of cells and the cells at the top are squamous in shape. The different shapes of the cells in the tissue, with columnar cells at the bottom and cuboidal cells in the middle, indicate that it is stratified. The squamous cells at the top further specify the type of tissue.

The presence of thick and thin purple lines weaving back and forth between the oblong cells indicates the presence of connective tissue. Connective tissue is characterized by its ability to connect, support, and protect different structures in the body. It is composed of various types of cells and extracellular matrix, which can contain fibers such as collagen (thick lines) and elastin (thin lines). This arrangement allows connective tissue to provide strength, flexibility, and structural integrity to organs and tissues.

Endochondral ossification is the process by which long bones develop and grow. It begins in the middle of the diaphysis, which is the shaft or main portion of the long bone. This is where the primary ossification center forms, and the bone tissue gradually replaces the cartilage model. The process then continues towards the ends of the bone, in the epiphyses. Therefore, the correct answer is "in the middle of the diaphysis."

When parathyroid levels are higher than normal, it indicates that there is an excess of parathyroid hormone being produced. Parathyroid hormone plays a crucial role in regulating calcium levels in the blood. Therefore, when parathyroid levels are increased, it leads to an increase in calcium levels in the blood.

Neuroglia cells readily undergo mitosis. Neuroglia cells are a type of support cells found in the nervous system. They play a crucial role in supporting and protecting neurons. Unlike neurons, which do not undergo mitosis and cannot be replaced if damaged, neuroglia cells have the ability to divide and undergo mitosis. This allows for the regeneration and repair of nervous tissue in response to injury or disease.

The Langerhans cell of the epidermis is responsible for providing immunity. These cells are a type of dendritic cell that play a crucial role in the body's immune response. They are able to capture and process antigens, which are foreign substances that can trigger an immune response. By presenting these antigens to other immune cells, such as T cells, the Langerhans cells help to initiate an immune reaction against potential threats. Therefore, the statement "provides immunity" is the correct answer.

The given answer states that all of the options mentioned - vasodilation of blood vessels, synthesis of scar tissue by fibroblasts, and granulation tissue formation - are typical events during deep wound healing. This implies that none of these options are not typical events during wound healing.

Desmosomes are cell adhesion structures that provide strong mechanical connections between cells. They are especially important in tissues that undergo a lot of stretch or mechanical stress, such as the skin or heart. Desmosomes anchor intermediate filaments within cells, allowing them to withstand tension and maintain tissue integrity. Therefore, in a tissue undergoing a lot of stretch, desmosomes would be the most important type of junction between cells to ensure the tissue remains intact and cohesive.

Mesenchyme is the correct answer because it is the embryonic connective tissue from which adipose tissue, bone tissue, hyaline cartilage tissue, and blood all develop. Mesenchyme is a type of undifferentiated tissue that has the ability to differentiate into various types of connective tissues and cells. It serves as a precursor for the development of these specialized tissues during embryonic development.

The cells that are responsible for the growth of hair are called the matrix. The matrix is located at the base of the hair follicle and contains actively dividing cells that produce new hair cells. These new cells are pushed upwards as the hair grows, eventually forming the hair shaft. The matrix is essential for hair growth and determines the thickness and length of the hair.

The correct answer is proximal phalanx II. The proximal phalanx II is the bone located at the base of the second toe. The toe ring is worn around this bone.

The opening of the ear canal is exposed to the external environment and is subjected to potential damage or infection. Stratified squamous tissue is a type of epithelial tissue that is well-suited for protection against abrasion and pathogens. It consists of multiple layers of flat cells that provide a barrier to prevent damage and infection. Therefore, it is expected to find stratified squamous tissue in the opening of the ear canal.

Collagen is the correct answer because it is the main organic component of bone matrix. It provides strength and flexibility to the bone, allowing it to withstand stress and resist fractures. Collagen fibers are arranged in a specific pattern, which contributes to the overall structure and function of the bone. Without collagen, the bone would be brittle and prone to breakage. Osteocytes, calcium phosphate salts, and haversian canals are also important components of bone, but they do not make up the organic component of the bone matrix.

Spongy bone is characterized by osteocytes in lacunae, which are small spaces or cavities within the bone matrix where the osteocytes, or bone cells, are located. This type of bone also contains Volkmann canals, which are channels that allow blood vessels and nerves to pass through the bone, and Haversian canals, which are central canals that contain blood vessels and nerves. Therefore, the correct answer is "all of the above" because all of these characteristics are present in spongy bone.

In the very center of the diaphysis of a long bone, fat would be found. The diaphysis is the long, cylindrical shaft of the bone, and it contains a hollow cavity called the medullary cavity. This medullary cavity is filled with yellow bone marrow, which is primarily composed of adipose (fat) tissue. This fat serves as a source of energy and also provides insulation and protection to the bone.

Chondroitin sulfate is a typical component of the matrix of hyaline cartilage. Hyaline cartilage is a type of connective tissue found in the body, such as in the nose, trachea, and joints. It provides support and flexibility to these structures. Chondroitin sulfate is a glycosaminoglycan that helps to maintain the integrity and structure of the cartilage matrix. It attracts water molecules, which contributes to the cushioning and lubrication of the cartilage. Therefore, chondroitin sulfate is a key component of hyaline cartilage.

Collagen is a protein that provides strength and flexibility to bones. Someone with "brittle bones" would have a deficiency of collagen in their bones, making them more prone to fractures and breaks. Calcium phosphate is responsible for the hardness of bones, osteocytes are bone cells that help maintain bone tissue, and blood vessels supply nutrients to bones. However, the lack of collagen is the main factor contributing to the brittleness of bones.

The epidermal cells receive their nourishment from blood vessels within the dermal papillae. The dermal papillae are small projections in the upper layer of the dermis that extend into the epidermis. These papillae contain blood vessels that supply oxygen and nutrients to the epidermal cells, allowing them to function properly. The other options, such as blood vessels within the stratum basale, keratinocytes, and sebaceous oil glands, do not play a direct role in providing nourishment to the epidermal cells.

Hyaline cartilage is a type of connective tissue that is found in various locations in the body. It is present in the external ear, trachea, and intervertebral discs. This type of cartilage provides support and flexibility to these structures. Therefore, the correct answer is "all of the above".

An osteoclast is a type of bone cell that is responsible for breaking down and resorbing bone tissue. In this scenario, if the cell is derived from a blood cell, it suggests that it has the ability to break down bone tissue, making it an osteoclast. Osteocytes are mature bone cells that are involved in maintaining bone tissue, but they do not have the ability to break it down. Osteoprogenitor cells are stem cells that can differentiate into osteoblasts, which are responsible for bone formation. Therefore, the most appropriate answer based on the given information is osteoclast.