BRS Cell Biology and Histology (Board Review Series)
Format: PDF / Kindle (mobi) / ePub
BRS Cell Biology and Histology is an outline-format review for USMLE and course exams, with abundant electron micrographs and conceptual line drawings, high-yield Clinical Considerations boxes, review questions at the end of each chapter, and a comprehensive USMLE-format examination at the end of the book. This Sixth Edition features 60 new full-color photomicrographs and a new full-color design with colorized line drawings. Content and questions have been updated, new Clinical Considerations have been added, and Clinical Considerations have been better integrated into the content.
A companion website will offer the fully searchable text and an interactive question bank.
LWBK615-c03[32-55].qxd 05/31/2010 10:31 AM Page 55 Aptara Answers and Explanations 1. C. A peroxisome originates from preexisting peroxisomes. It imports specific cytosolic proteins and then undergoes fission. The other organelle that divides by fission is the mitochondrion (see Chapter 3 II A 10). 2. D. Cells import cholesterol by the receptor-mediated uptake of LDLs in coated vesicles. Certain individuals inherit defective genes and cannot make LDL receptors, or they make defective receptors
most common in connective tissue proper. 2. Dense regular connective tissue is present in (A) (B) (C) (D) (E) capsules of organs. basement membrane. tendons. skin. dermis. 3. Of the following cell types found in connective tissue, which is most often present along capillaries and resembles fibroblasts? (A) (B) (C) (D) (E) Plasma cell Lymphocyte Macrophage Mast cell Pericyte 4. Synovial fluids of normal joints are usually devoid of collagen. Patients with rheumatoid diseases have various
structures, and provide a calcium reserve (bone contains about 99% of the body’s calcium). It is a dynamic tissue that constantly undergoes changes in shape. Applied pressure results in bone resorption. Applied tension results in bone formation. B. Structure 1. Bone matrix a. The inorganic (calcified) portion of the bone matrix (about 65% of the dry weight) is composed of calcium, phosphate, bicarbonate, citrate, magnesium, potassium, and LWBK615-c07[92-108].qxd 05/31/2010 10:37 AM Page 96
bone growth. (D) Its inner layer contains osteoprogenitor cells. (E) Its outer layer is devoid of fibers. 3. Which one of the following statements is characteristic of osteocytes? (A) They communicate via gap junctions between their processes. (B) They contain large amounts of RER. (C) They are immature bone cells. (D) They are housed as isogenous groups in lacunae. (E) They give rise to osteoclasts. (A) (B) (C) (D) (E) Potassium Calcium Iron Carbohydrates Protein 6. A 22-year-old woman
lymphocytes and macrophages Induces mitosis of activated T and B cells Induces mitosis of B cells, their transformation into plasma cells; promotes isotype switching from IgM to IgG and IgE Induces mitosis, maturation of B cells; promotes isotype switching from IgM to IgE Activates T cells, induces maturation of B cells to IgG-forming plasma cells Inhibits formation of TH1 cells; retards their ability to manufacture cytokines Activates NK cells, facilitates formation of TH1-like cells Macrophages