1. Which of the following drugs is a non-selective beta-blocker?
a) Atenolol
b) Propranolol
c) Metoprolol
d) Bisoprolol
Ans: b
Propranolol is a non-selective beta-blocker that inhibits both β1 and β2 adrenergic receptors. It is commonly used for managing hypertension, anxiety, and certain types of arrhythmias. In contrast, atenolol, metoprolol, and bisoprolol are selective for β1 receptors, primarily affecting cardiac output and heart rate without significantly influencing bronchial tone.
2. The term “metaplasia” refers to:
a)Increased cell size
b)Replacement of one cell type with another
c)Abnormal cell growth
d)Cell death
Ans: b
Metaplasia involves the transformation of one differentiated cell type into another, often as an adaptive response to chronic stressors, such as smoking leading to respiratory epithelium changing from ciliated columnar to squamous cells. While metaplasia can be reversible, it may predispose tissues to dysplasia or cancer if the irritant persists.
3. Which of the following is the most common type of oral cancer?
a)Squamous Cell Carcinoma
b)Adenoid Cystic Carcinoma
c)Mucoepidermoid Carcinoma
d)Osteosarcoma
Ans: a
Squamous Cell Carcinoma (SCC) is the most prevalent oral cancer, making up approximately 90% of all oral malignancies. It often arises in the oral cavity, especially on the lateral borders of the tongue and the floor of the mouth. Key risk factors include tobacco use (smoking and chewing), heavy alcohol consumption, and infection with high-risk strains of the Human Papillomavirus (HPV). Early detection and intervention significantly improve survival rates.
4. Which of the following lesions is characterized by a “ground-glass” appearance on radiographs?
a)Osteoma
b)Osteosarcoma
c)Fibrous Dysplasia
d)Paget’s Disease
Ans: c
Fibrous dysplasia is a benign condition resulting from the abnormal development of bone and is characterized radiographically by a “ground-glass” appearance. This occurs due to the replacement of normal bone with fibrous tissue, leading to weakened structural integrity. Fibrous dysplasia can generally display the following three main imaging features:
Beyond that, appearances are usually smooth and homogeneous with endosteal scalloping and cortical thinning 5. The borders are well defined and the cortex is usually intact but thinned due to the expansive nature of the lesion 5. Other features include:
5. In which type of hypersensitivity reaction do IgE antibodies play a significant role?
a)Type I
b)Type II
c)Type III
d)Type IV
Ans: a
ype I hypersensitivity, or immediate hypersensitivity, is mediated by IgE antibodies that bind to allergens and trigger mast cells and basophils to release histamine and other mediators. Type I hypersensitivities include atopic diseases, which are an exaggerated IgE mediated immune responses (i.e., allergic: asthma, rhinitis, conjunctivitis, and dermatitis), and allergic diseases, which are immune responses to foreign allergens (i.e., anaphylaxis, urticaria, angioedema, food, and drug allergies).
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