Dentosphere : World of Dentistry

 # Which of the following types of fibers are found in loose connective tissue?  a. Yellow elastic and white collagen.  b. White fibrous, elastic, and reticular.  c. Elastic and collagenous.  d. Fine reticular The correct answer is: A. Yellow elastic and white collagen. Yellow elastic and white collagen are found in loose connective tissue. White fibrous, elastic, and reticular fibers are found in dense irregular connective tissue. Elastic and collagenous fibers are found in elastic cartilage. Fine reticular fibers are found in reticular tissue.  CLICK HERE FOR MORE MCQs  

# Bone replaces cartilage by which of the following processes?  a. Interstitial growth b. Endochondral development c. Intramembranous bone formation d. Membranous bone formation The correct answer is: B. Endochondral development. Interstitial growth is growth within the cartilage matrix by each cartilage cell enlarging and forming matrix around each cell. Bone replaces cartilage by a process termed endochondral bone development. Intramembranous bone is formed when collagen fibers of connective tissue organize into closely knit meshwork, and this matrix gradually calcifies into bone. Intramembranous bone formation is also known as membranous bone formation. CLICK HERE FOR MORE MCQs  

 # The cerebral hemispheres develop from which of the following vesicles?  a. Forebrain b. Midbrain c. Hindbrain d. Primary brain The correct answer is a. Forebrain.  The cerebral hemispheres develop from the forebrain vesicles. CLICK HERE FOR MORE MCQs

 # The first step of mitosis is which of the following?  a. Telophase b. Metaphase c. Prophase d. Anaphase  The correct answer is: C. Prophase. Prophase is the first step of mitosis in which four structural changes occur. CLICK HERE FOR MORE MCQs

 # Melanoblastoma are derived from: A. Basal epidermal cells B. Neural crest cells C. Prickle cells of epidermis D. Somato pleuric mesoderm The correct answer is B. Neural crest cells. Melanoblastoma are derived from Neural crest cells. CLICK HERE FOR MORE MCQs

 # Notochord develops in: A. 3rd week B. 3rd month C. 6th month D. 10th month The correct answer is A. 3rd week. The notochord arises from axial mesoderm at about 16 days and is completely formed by the beginning of the fourth week. It defines the longitudinal axis of the embryo, determines the orientation of the vertebral column, and persists as the nucleus pulposus of the intervertebral discs. CLICK  HERE FOR MORE MCQs

 # Implantation occurs at the stage of: A. Zygote B. Morula C. Blastocyst D. Primary villi The correct answer is C. Blastocyst. The blastocyst is a structure formed in the early development of mammals. It possesses an inner cell mass (ICM) which subsequently forms the embryo. The outer layer of the blastocyst consists of cells collectively called the trophoblast. This layer surrounds the inner cell mass and a fluid-filled cavity known as the blastocoel. The trophoblast gives rise to the chorion and amnion that surround the embryo. In humans, blastocyst formation begins about 5 days after fertilization when a fluid-filled cavity opens up in the morula, the early embryonic stage of a ball of 16 cells. The blastocyst has a diameter of about 0.1–0.2 mm and comprises 200–300 cells following rapid cleavage (cell division). About seven days after fertilization, the blastocyst undergoes implantation, embedding into the endometrium of the uterine wall. There it will undergo further developm...