4 Histology Answers and Explanations I. Definition and Classification of of Tissues A. Mult Multip iple le Choi Choice ce Ques Questio tions ns 1. (d) – Tissues are classifi classified ed using using structura structurall and and functional functional attributes. attributes. 2. (a) – In a medical medical histology histology course, course, students students learn learn what what constitutes constitutes normal normal histologica histologicall structure. structure. A course in histology is usually followed by one in pathology, in which abnormal, or diseased, tissues are studied. 3. (a) – Epithelia Epitheliall tissues tissues cover body organs organs and line body body cavities, cavities, tubes, tubes, and and ducts. 4. (b) – Cart Cartilag ilagee is a speci specific fic type type of of connect connective ive tiss tissue. ue. B. True– True–Fal False se Ques Questio tions ns 1. True – Tissues fit between between cells and organs organs in the levels levels of of body organization. organization. 2. False – In certain certain tissues, tissues, the the matrix matrix is semisoli semisolid d and in others it it is solid-rig solid-rigid. id. 3. False – The The outer layer layer of skin, skin, called called the epidermis, epidermis, is composed composed of stratified stratified squamou squamouss epithelial epithelial tissue. tissue. 4. True – Connective Connective tissues tissues bind bind and support support structur structures es or organs, organs, such such as muscles. muscles. II. II.
Deve Develo lopm pmen enta tall Exp Expos ositi ition on of Tiss Tissue uess A. Mult Multip iple le Choi Choice ce Ques Questio tions ns 1. (c) – For the the most part, part, the placenta placenta is is derived derived from trophoblas trophoblastt cells that that have specializ specialized ed from the the morula. 2. (b) – The formatio formation n of ectoderm ectoderm and endoderm endoderm promotes promotes the developmen developmentt of mesoderm. mesoderm. The The hypodermis hypodermis is not a primary germ layer. 3. (b) – The The nervous nervous system system and the epidermis epidermis of the skin skin both both form from ectoderm ectoderm.. B. True– True–Fal False se Ques Questio tions ns 1. False – A zygote is is diploid. diploid. Twenty-three Twenty-three chromoso chromosomes mes are contribut contributed ed by the sperm sperm cell cell and 23 chromosomes are contributed by the ovum. 2. True – Most Most of the placenta placenta develops from the trophoblast, trophoblast, and the the remainder remainder develops develops from from maternal maternal endothelial tissue. 3. False False – This This space space is is referre referred d to as the the amniot amniotic ic cavit cavity. y. 4. True – The endoderm forms the the developing developing gut (GI (GI tract) tract) and structures structures that that derive derive from the the gut, such such as the liver and pancreas.
III III.
Epit Epithe heli lia al Tiss Tissu ue A. Mult Multip iple le Choi Choice ce Ques Questio tions ns 1. (a) – The thinness thinness of of simple squamous squamous epithelium epithelium facilitate facilitatess diffusion diffusion (e.g., within the pulmonary pulmonary alveoli) and filtration (e.g., within the glomeruli of the kidneys). 2. (a) – Simp Simple le colum columnar nar epith epitheli elium um lines lines the the GI tract. tract. 3. (d) – The fact fact that each each cell of of pseudostratifi pseudostratified ed squamous squamous epithelium epithelium contacts contacts the the basement basement membrane membrane precludes stratification of the cells of this tissue. 4. (b) – Nonkeratini Nonkeratinized zed stratified stratified squamous squamous epithelium epithelium is found found lining lining the cavities cavities that open into the body, such as the oral cavity and the anal cavity 5. (c) – The distensio distension n capability capability of this this epithelium epithelium permits permits the the urinary bladder to to expand as as it stores stores urine. 6. (d) – Sebaceou Sebaceouss glands glands of of the skin are holoc holocrine rine..
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B. True– True–Fal False se Ques Questio tions ns 1. True – Simple Simple epithelia epithelia consist consist of a single single layer layer of cells, cells, so that that each cell cell has an exposed exposed surface surface and a surface in contact with the basement membrane. 2. True – These are are specialized specialized sensory epithelial epithelial cells, cells, such as those within the nasal nasal cavity. cavity. 3. True – The process of of mitosis mitosis within within this layer layer ensures ensures replenishment replenishment of worn and and damaged damaged cells on the exposed surface. 4. True – The process process of of dehydration dehydration and flattenin flattening g is called cornification. cornification. 5. False – A rich blood blood supply into the epithelia epitheliall layer composin composing g the wall wall of the oral oral cavity ensures that that the cells of this layer remain alive. 6. False – Unicellu Unicellular lar exocrine exocrine glands glands are ductless; ductless; multicel multicellular lular exocrine exocrine glands glands secrete secrete through through ducts to to the surface of tissues. C. Labe Labeli ling ng Que Quest stio ions ns 1. sim simple ple tubu tubula lar; r; intestinal glands; aid digestion 2. simp simple le coil coiled ed tubu tubula lar; r; sweat glands; regulate temperature 3. bran branch ched ed acin acinar ar;; sebaceous glands of the skin; skin conditioners IV. IV.
Con Connec nectiv tive Tis Tissue A. Mult Multip iple le Choi Choice ce Ques Questio tions ns 1. (d) – Fibrobl Fibroblast astss are remarka remarkable ble in their their abili ability ty to differ differenti entiate. ate. 2. (a) – Loose Loose connec connective tive tissu tissuee is a bindin binding g and packin packing g type tissu tissue. e. 3. (c) – Tightly Tightly packed, packed, interwoven interwoven collagenous collagenous fibers fibers within within tendons tendons and ligamen ligaments ts provide provide incredible incredible strength as well as flexibility. 4. (b) – The The deriv derivatio ation n of this this term term convey conveyss its mean meaning: ing: peri peri– means “around”; chondro means “cartilage.” 5. (a) – The fibrocart fibrocartilage ilage in interver intervertebral tebral discs discs permits permits compression compression,, which facilita facilitates tes spinal spinal movements. movements. 6. (c) – There There is a singl singlee osteocyt osteocytee in each each lacuna lacuna (plural (plural,, lacunae) lacunae).. 7. (d) – Critical Critical numbers numbers of of healthy healthy platelets platelets (thrombocytes) (thrombocytes) facilitate facilitate clotting. clotting. B. True– True–Fal False se Ques Questio tions ns 1. True – Mesenchym Mesenchymee is found only only in the embryo, where it it plays a crucial crucial role role in the formati formation on of organs. organs. 2. False False – Mast cells cells actua actually lly produce produce an an anticoag anticoagulan ulant, t, heparin heparin.. 3. False – The lipid lipid content content is eliminat eliminated ed from the tissue, tissue, but but the cells cells remain. remain. 4. False – Fibrocarti Fibrocartilage lage is found found at the symphysis symphysis pubis, pubis, and hyaline hyaline cartilage cartilage is found found between between the ribs ribs and the sternum. 5. True – The mineralize mineralized d matrix matrix of bone bone tissue tissue gives the skeletal skeletal system system its its strength. strength. 6. False – The The hardness hardness is due to to the calcium calcium phosphate phosphate crystals crystals within within the bone matrix; matrix; collagenous collagenous fibers fibers provide some flexibility. C. Matc Matchi hing ng Que Quest stio ions ns 1. (g) 2. (d) 3. ( f ) 4. (c )
5. ( a) 6. ( e) 7. ( b )
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V.
Muscle Tissue A. Mult Multip iple le Choi Choice ce Que Questi stion on 1. (b) – The The intercalated intercalated discs of of muscle muscle tissue tissue help to hold adjacent adjacent fibers together. together. 2. (c) – Of Of the three three muscle muscle tissue tissue types, types, only only skeletal skeletal muscle muscle fibers fibers are multinucleated multinucleated.. B. True– True–Fal False se Ques Questio tions ns 1. True – Being elongated elongated in this this direction direction provides provides maximum maximum strength strength during contraction. contraction. 2. False False – Smooth Smooth muscle muscle is is nonstr nonstriate iated d and invo involunt luntary. ary. 3. False – The The fibers of skeletal skeletal muscles muscles are elongated elongated and and multinucleat multinucleated, ed, but they they do not bifurcate bifurcate..
VI.
Nervous Tissue A. Mult Multip iple le Choi Choice ce Ques Questio tions ns 1. (a) – A dendrite dendrite receives receives a stimulu stimuluss and passes passes the impulse impulse through through the cell cell body and and axon of the neuron. neuron. 2. (d) – The The nucleus nucleus of a neuro neuron n is contain contained ed within within the the cell cell body. body. B. True– True–Fal False se Ques Questio tions ns 1. False – A nerve fiber fiber is generally generally considere considered d to be the axon axon of a neuron. neuron. It may may be myelinated myelinated or or nonmyelinated. 2. False – Neurons are the basic units; units; neuroglia neuroglia assist the neurons neurons in various ways. 3. True True – Neuroglia Neuroglia can can mitoti mitoticall cally y divide, divide, but but neurons neurons cannot. cannot. 4. False False – Only Only the neuro neurons ns transm transmit it nerve nerve impu impulses lses..
VII. VII.
Clin Clinic ical al Consi Conside dera rati tion onss A. Mult Multip iple le Choi Choice ce Ques Questio tions ns 1. (a) – Atrophy Atrophy is the the consequ consequence ence of lack lack of use. 2. (c) (c) – The The pref prefix ix iso– means “equal”; “like.” B. True– True–Fal False se Ques Questio tions ns 1. True True – Necro Necrosis sis is deri derived ved from the Greek Greek nekros, meaning “corpse.” 2. False – Living tissue tissue is is removed removed during during a biopsy, biopsy, although although it it dies shortly thereafter. thereafter.
VIII. VIII. Chapte Chapterr Rev Review iew A. Comp Complet letio ion n Que Questi stion onss 1. matrix 2. primary germ 3. basement membrane 4. endothelium/mesothelium 5. compound acinar/apocrine 6. Goblet 7. keratin 8. heparin 9. Leukocytes
10. 11. 12. 13. 14. 15. 16. 17. 18.
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neuroglia basale Exocrine ground substance mesenchyme edema lacunae intercalated discs nerve fiber
