HARD HISTO Q_A 21

7. Epithelial tumors can be identified by the presence of a. BRCA1/BRCA2, blood b. Calcitonin, blood c. Cytokeratins, blood d. Beta-2-microglobulin, CSF 8. Cilia/Kinocilia are grown from what structure in the cortical cytoplasm? a. Basal lamina b. Basal bodies c. Axoneme core d. Brush border 9. Flagella in humans are only found in _______ . Flagella are highly organized into an _________. a. Spermatogonium; axoneme core b. Spermatozoa; axoneme core c. Spermatozoa; centriole d. Spermatogonium; centriole 10. Cholera toxins, as well as cytomegalovirus (CMV) permeabilize the cell junction by acting on: a. ZO-1/3 b. JAM c. Claudins d. Occludins 11. Junctional adhesion molecules (JAM) are often found with _______ and function to _________. a. Occludins ; transport protein products into the tissues b. Claudins ; transport of protein products into the tissues c. Occludins ; transport lymphocytes out of the bloodstream d. Claudins ; transport of lymphocytes out of the bloodstream 12. Match the junction with its correct function. a. Tight junctions → adhesion b. Anchoring junctions → barrier c. Desmosome → stability d. Zona occludentes → adhesion

25. Which type of microscopy would you use to evaluate blood composition? a. SEM b. Flow Cytometry c. FISH (antibody labelling) d. Fluorescence 26. Which of the following is NOT a preparation artifact? a. Postmortem changes b. Shrinkage or swelling c. Sectioning damage d. Cleaning damage NUCLEUS 27. Dying or dead cells have all of the following EXCEPT: a. Pyknosis b. Lipolysis c. Karyorrhexis d. Karyolysis 28. Mutations in the proteins of the nuclear pore complex can result in a. Carcinomas b. Muscular dystrophy c. Progeria(s) d. Leukemias 29. Mutations in the nuclear lamina can result in all of the following EXCEPT: a. Emery-Dreifuss Muscular Dystrophy b. Chromosomal disorders c. Progeria(s) d. Congenital scoliosis 30. Match the structure with the appropriate function or descriptor. a. Nucleolus → site of active rRNA transcription b. Pars Fibrosa → site in nucleus where ribosomes are assembled c. Pars Granulosa → site where ribosomal assembly starts d. Fibrillar Center → has a honeycomb appearance

43. Both Alport Syndrome and Goodpasture Syndrome involve targeting of Type IV Collagen. What is the major difference in characterization between the two syndromes? a. Alport Syndrome manifests with ocular issues, while Goodpasture Syndrome manifests with hemorrhage. b. Alport Syndrome is X-linked dominant, while Goodpasture Syndrome is autoimmune-mediated. c. Alport Syndrome has sensorineural deafness, while Goodpasture Syndrome manifests with congenital deafness. d. Alport Syndrome is autoimmune-mediated, while Goodpasture Syndrome requires viral exposure. NERVES 44. Select the correct statement regarding neuronal structure. a. Unmyelinated axons allow for faster saltatory conduction between areas of white matter. b. Schwann Cells produce myelin in the CNS. c. Oligodendrocytes produce myelin in the PNS. d. The terms “Myelin” and “White Matter” are describing the same substance. 45. Select the correct flow of incoming information through the neuron. a. Axons → Dendrites → Soma b. Dendrites → Axons → Soma c. Dendrites → Soma → Axons d. Axons → Soma → Dendrites 46. Which of the following are significant in protein synthesis? a. Ependymal cells b. Nissl bodies c. Microtubules d. Dendrocytes 47. Neurotubules are microtubules that line the ______ & _______ to function in transport. a. Axons & soma b. Incoming axons & outgoing axons c. Soma & dendrites d. Axons & dendrites 48. Anterograde (+) transport is done by ________, and retrograde transport (-) is done by ________. a. Kinesin, Dynein b. Dynein, Kinsein c. Actin, Myosin d. Myosin, Actin

61. Type IV collagen composes the a. Anchoring fibers in the basal lamina b. Reticular fibers c. Basal Lamina d. Hemidesmosomes 62. Type VII collagen composes the a. Anchoring fibers in the basal lamina b. Reticular fibers c. Basal Lamina d. Hemidesmosomes 63. Type XVII collagen composes the a. Anchoring fibers in the basal lamina b. Reticular fibers c. Basal Lamina d. Hemidesmosomes 64. Select the correct diagnosis with its pathophysiology. a. Scurvy → Mutations in alpha 1 & 2 genes b. Osteogenesis imperfecta → abnormal proline hydroxylation c. Ehlers-Danlos Syndrome → defect in either lysyl hydroxylase or lysyl oxidase d. Systemic Sclerosis → mutations in alpha 1 & 2 genes 65. Which of the following HAS hydroxylysine? a. Collagen Fibers b. Elastic Fibers c. A & B d. Neither 66. Marfan Syndrome is caused by a genetic mutation in a. Elastin b. Fibrillin-1 c. COL1A1 d. COL1A2

79. Osteoprogenitor cells do not produce WHICH cell type? a. Osteoblasts b. Osteoclasts c. Chondrocytes d. Fibroblasts 80. Osteoblasts secrete which collagen type? a. Collagen Type I b. Collagen Type II c. Collagen Type IV d. Collagen Type VII 81. Osteocytes develop long cellular processes that radiate from the a. Matrix b. Canaliculi c. Lacuna d. None of the above 82. Which of the following cells respond to mechanical stimuli to mediate bone remodeling and growth? a. Osteoprogenitor cells b. Osteoblasts c. Osteocytes d. Osteoclasts 83. In comparison to osteoblasts, osteocytes are a. Bigger b. The same size c. Smaller d. Cooler 84. Osteocytes communicate with other nearby osteocytes via _________ which travel through canaliculi. a. Dendrites b. Chemical messengers c. Gap junctions d. Tight junctions

96. Choose the best answer choice for the following statement: In excess, this hormone causes gigantism in children. In adults, it causes acromegaly. a. Testosterone b. Growth hormone c. Estrogen d. Calcitonin 97. Testosterone will stimulate a. Osteoblasts b. Epiphyseal plate growth c. Inhibits osteoblast apoptosis d. A & B e. A & C f. None of the above 98. Menopausal women are at an increased risk of a. Decreased folic acid synthesis b. Thyroid cancer c. Osteoporosis d. Osteomalacia 99. Select the most correct statement regarding parathyroid hormone (PTH). a. Produced by C cells of the thyroid b. Low, intermittent levels of PTH are always expected c. Prolonged treatment with PTH stimulates production of RANKL d. PTH increases serum calcium levels e. A & B f. A, B, & C g. B, C & D h. All of the above 100-105. Match the following cartilage types and features with its correct statement. 100. Hyaline cartilage a. Adjacent to chondrocytes, stains dark blue. 101. Elastic cartilage b. Stimulates collagen production 102. Fibrocartilage c. Contains Type I collagen 103. IGF-1 d. Does not calcify with age 104. Cortisol e. Contains Type II collagen 105. Territorial matrix f. Inhibits collagen production g. Space between chondrocytes, stains light blue.

121. A big physical difference between large elastic arteries and muscular arteries is: a. Muscular arteries have a more prominent internal elastic membrane b. Large elastic arteries have smooth muscle c. Muscular arteries have lots of elastic fibers d. Large elastic arteries contract to maintain BP during systole 122. A unique feature of metarterioles are a. The internal elastic membrane b. The basal lamina c. The presence of a sphincter d. The presence of Ca++ 123. Pericytes surround capillaries and work to support and stabilize the vessel. They also a. Prevent leakage b. Allow for flow of small, porous molecules through the capillary c. Allow leakage d. Can act as stem cells 124. Which type of vein will have NO tunica adventitia? a. Venules b. Small veins c. Medium veins d. Large veins 125. At which layer of the heart would you be likely to find Purkinje fibers? a. Endocardium b. Subendocardium c. Myocardium d. Epicardium 126. The Purkinje fibers function to (select the MOST correct answer): a. Generate electrical signals b. Receives electrical impulses c. Transmit impulses to the ventricles d. Receive impulses in the terminal portion

ANSWERS PLASMA MEMBRANE SPECIALIZATIONS + MICROSCOPIC IMAGES 1. C, Cells are organized into tissues which are organized into organs. Slide 2, lecture 11 (epithelium). 2. B, Bone is not a type of tissue. Slide 2, lecture 11 (epithelium). 3. A, Relaxation is not a function of epithelia. Slide 3, lecture 11 (epithelium). 4. B, Microvilli (1 um) < Cilia/Kinocilia (5-10 um) < Stereocilia (10-100 um) < Flagella (100 um). Plasma Membrane Specialization Notes, pages 1 through 2. 5. A, True , most types of epithelia CAN regenerate. Slide 4, lecture 11 (epithelium). 6. C, Carcinoma . Epitheliomas can be benign (papilloma/adenomas) to malignant (carcinomas). The other terms are descriptors used for various body protrusions. 7. C, Cytokeratins . BRCA1/BRCA2 refers to a genetic marker commonly used to evaluate risk of certain forms of breast cancer. Calcitonin is often measured when evaluating for thyroid cancer. Beta-2-microglobulin is measured in multiple myeloma, chronic lymphocytic leukemia, and other lymphomas. You don’t have to know any of that. Just the cytokeratins part. 8. B, Basal bodies . Plasma Membrane Specialization Notes, page 2. 9. B, Spermatozoa; axoneme core . Spermatozoa specifically refer to mature spermatocytes, while spermatogonium (early form of sperm in spermatogenesis) do not have flagella. Certain forms of cilia can be centriole-derived, but the centriole has 9 triplets in comparison to axoneme’s 9 doublets. Plasma Membrane Specialization Notes, page 2. 10. A, ZO-1/3 . Cholera/CMV permealize the junction by acting on zona occludens proteins. 11. D, Claudins ; transport of lymphocytes out of the bloodstream and into the tissues. 12. C, Desmosome → Stability . Reminder: zona occludentes = tight junctions, so A = D, and their function is a barrier. Anchoring junctions do adhesion. 13. D, Zonulae occludentes = tight junctions are a common target of pathogenic agents. Anchoring junctions (A) = zonula adherens (B) hehehehehe 14. B, Claudins . 15. C, Dust mites → Occludin + ZO-1 . H. pylori → ZO-1 + JAM, C. perfringens → Claudins, Reovirus → JAM. NSP4 is the viral endotoxin of reovirus, not the target protein. Sorry for the douche “more right” question.

16. D, Desmosome . It causes severe blistering of the skin. Vulgaris → “Vulgar” skin blisters. 17. B, Desmosomes . Fun CC-question-within-the-answer-section: Pemphigus Vulgaris patients are most likely at risk for what? Metastasizing tumors. Boom. 18. A, tight junction → adherens junction → desmosome . 19. B, Connexins are the major constituent of hemichannels while connexons are multiple hemichannels . The major constituent of gap junction transmembrane proteins are connexins; six molecules of connexin create a hemichannel, and when adjacent cells each provide one hemichannel, it forms a connexon. 20. A, 6 ; hemichannel . 6 molecules of connexin form a hemichannel, and multiple hemichannels form a connexon. 21. C, Cx-32 → demyelination of peripheral nerve s. Cx-26 → congenital deafness, Cx-46 + Cx-50 → cataracts of lens of eye. I totally made up Cx-23. 22. B, dermis and epidermis . 23. D, Integrins . Everything else I listed were ECM molecules associated with adhesion plaques (focal contacts). 24. C, Collagen type XVII . Bullous pemphigoid is an autoimmune disease due to antibody creation to proteins BP230/BPAG1, Collagen Type XVII/BPAG2. 25. B, Flow Cytometry , is for single-cell analyses and is especially good for blood composition. SEM is for looking at the surface of cells. FISH uses DNA probes to localize genes. Fluorescence is good for an immunoassay of a whole structure. 26. D, cleaning damage . I totally made up cleaning damage. Everything else is real.

NUCLEUS 27. B, lipolysis . Karyorrhexis is nuclear fragmentation, pyknosis is nuclear & chromatin condensation, and karyolysis is the complete disappearance of the nucleus. Lipolysis is the breakdown of fats and other lipids by hydrolysis to release fatty acids… I just picked something else with -lysis on the end. 28. D, Leukemias . Muscular dystrophy and progerias are associated with the nuclear lamina. Carcinoma I just threw in there. 29. B, Chromosomal disorders . Mutations in the nuclear lamina (laminopathies) are linked to diseases causing decline/wasting of tissues/organs or premature wasting. 30. C, Pars Granulosa → site where ribosomal assembly starts . The nucleolus is the site in the nucleus where ribosomes are assembled and has a honeycomb appearance; the pars fibrosa is the site of active rRNA transcription; the fibrillar center contains genes from the 5 acrocentric chromosomes & rRNA genes. 31. B, the q-Arm is the long arm of the chromosome . Humans have 46 chromosomes, the Hayflick Limit is the maximum # of replications that somatic cells can undergo, and barr bodies are inactivated X chromosomes. 32. D, 1. Dark, 2. Inactive, 3. Light, 4. Active 33. A, H1. A histone octamer, often referred to as “beads on a string” appearance, are made up of 2 copies of histones H2a, H2b, H3, and H4. H1 acts as “linker DNA” between the clusters of DNA & histone octamers to form nucleosomes. 34. B, Histone methylation increases condensation, resulting in decreased transcription . Here comes my crude memory hook: meth heads sweat a lot (methylation ↑ condensation) and forget things (↓ transcription). Acid makes you lay down (acetylation ↓ condensation) and trip (↑ transcription).

EPITHELIUM 35. B, Small ducts of exocrine are characterized with simple cuboidal. 36. D, Simple squamous . 37. A, Small intestine . Surface of ovary and kidney tubules are simple cuboidal, mesothelium is simple squamous. 38. C, Stratified Squamous . For examples of others listed, see the chart on Austin and I’s HY sheet pages 8-9. 39. C, Rarely . Cancer in children is rarely of epithelial origin, 90% of tumors in people >45 years are epithelial-derived. 40. G, IV & VII . 41. A, Type VII collagen . Type IV issues are associated with Alport Syndrome and Goodpasture syndrome. Other ones come later. 42. C, Glomerulonephritis . Retinopathy and lens dislocation are characteristics of Alport; pulmonary hemorrhage describes Goodpasture. 43. B, Alport Syndrome is X-linked dominant, while Goodpasture Syndrome is autoimmune-mediated . Answer choice A correctly associates symptoms with each, but it is not the major difference between the two syndromes. Give yourself a half point if you put A, I won’t tell anyone.

NERVES 44. D, The terms “Myelin” and “White Matter” are describing the same substance . Myelinated axons allow for faster saltatory conduction, Schwann Cells produce myelin in the PNS, Oligodendrocytes produce myelin in the CNS. 45. C, Dendrites → Soma → Axons . Dendrites directly receive incoming signals, and send them to the stoma for integration; the stoma receives, integrates, and sends signals; the axons send the sent signal from the stoma to the target cell/tissue. 46. B, Nissl bodies . Ependymal cells line brain ventricles and make CSF. Microtubules (MTs) have a variety of functions, but specifically, neurotubules are MTs that line axons & dendrites that function in transport. Dendrocytes are a dendritic cell that originates in bone marrow. 47. D, Axons & Dendrities . Think about the two parts of the neuron that function in movement of information. Soma just integrates. I through in ingoing & outgoing axons just to confuse you, there’s really just outgoing axons. 48. A, Kinesin, Dynein. Anterograde (+) = Kinesin, Retrograde (-) = Dynein. When you die you lose life (-). Myosin and actin I also just threw in to confuse you, but those are microfilaments, and we’re talkin microtubules. 49. B, Perineurium . Epineurium is the outermost layer and composed of dense CT, and the endoneurium surrounds a single nerve fiber. I made up myoneurium, and then Googled it to see if it was a real thing. It seems that the only other people who use it also make it up specifically to trick you, so watch out! 50. A, Pacinian Corpuscles . Pacinian corpuscles sense vibrations & deep pressure. Meissner’s Corpuscles sense light touch. These last two are not mentioned in the notes directly, so beyond the scope of knowledge, but: Merkel’s Corpuscle detects sustained pressure and underlies the perception of form and roughness on the skin, and Ruffini corpuscle detects tension deep in the skin and respond to stretch. 51. B, Meissner’s Corpuscles . See 50.

CONNECTIVE TISSUE 52. C, Vasoconstriction . Lower venous blood flow, increased capillary permeability, vasoDILATION, and starvation are all causes of edema. 53. B, Extra-cellular matrix (ECM) . This is a definition, so all of the rest is just wrong. 54. C, Chondronectin → allows chondrogenic cells to attach to collagen . First, I’m so sorry for this douche-move question. Secondly, Fibronectin functions in cell adhesion and migration (A/D). Laminin aids in epithelial cell adhesion to the basal lamina (B). Chondronectin (found in cartilage) and allows chondrocytes, not chondrogenic cells, to attach to Type 2 collagen. 55. C, Preprocollagen → Procollagen → Cleavage of Propeptides → Mature Collagen. Preprocollagen has the signal sequence cleaved in the ER to form procollagen (which prevents aggregation into fibrils inside of the cell). It then exits the cell and is cleaved of its propeptides, yielding mature collagen. 56. B, Lysyl oxidase . Others have little or no involvement in collagen synthesis. And no, to you super nerds, hydroxylase still isn’t right. Vitamin C allows for hydroxylation and crosslinking of pro-collagen catalyzed by lysyl hydroxylase. No lysyl hydroxylase doesn’t yield a lack of collagen, it yields brittle collagen OR mild Ehler-Dahlos route -_- Decreased lysyl oxidase levels are associated with Menkes disease, which is much more serious and presents with issues like growth failure and nervous system deterioration. Hence major enzyme. Don’t comment don’t @ 57. A, Type I. Type I collagen is found in connective tissue, bones, dentin, and capsules. 58. E, All of the above . :) 59. D, A & B = Hyaline & Elastic. 60. C, Reticular Fibers. It can be found in hematopoietic and parenchymal organs (blood vessels, liver, spleen, smooth muscle, etc.) 61. C, Basal Lamina . 62. A, Anchoring fibers in the basal lamina. 63. D, Hemidesmosomes . (just a few defining questions for ya <3 ) 64. C. Ehler-Danlos Syndrome → defect in either lysyl hydroxylase or lysyl oxidase . Scurvy → abnormal proline hydroxylation, osteogenesis imperfecta → mutations in alpha 1 & 2, systemic sclerosis → excessive collagen accumulation. 65. A, Collagen Fibers have hydroxylysine, elastic fibers do not. 66. B, Fibrillin-1 gene . Elastin is the mature component of the elastic fiber, or what Fibrillin may “eventually” yield to. COL1A1 and COL1A2 are both collagen genes. 67. D, Turn over ECM . Fibroblasts secrete ECM constantly to make CT, ground substance, & turn over various ECM portions. 68. D, Sentinel cells → contain granules of histamine. Mast cells (B) = Sentinel cells. Macrophages → initiation of immune response (A), plasma cells → produce antibodies (C).

69. B, Antibody recognition . Basophilic (purple) granules found within mast cells contain histamine, neutral proteases, neutrophil chemotactic factor (NCF), eosinophil chemotactic factor (ECF), Heparin, Il-1, and TNF. 70. D, IgE . This is beyond the point of knowledge, but here’s basically what happens: you have an allergen! → IgE Abs (antibodies) produced → Mast Cells bind to IgE → Sensitization → IgE/Receptor Cross-Link → Release of granules + produce leukotrienes. 71. C, Plasma Cell . Plasma cells produce antibodies and have a characteristically “clock-faced nucleus” and tons of rough ER. 72. C, Yellow, more; Brown, less. 73. D, Insulin, Norepinephrine . HSL = Hormone-Sensitive Lipase (Webster voice: it’s in the notes). HSL = activated when stored fat needs to be broken down into Free FAs and Glycerol, mostly for the purpose of “reharvesting” albumin to areas of need. More specific mechanism, so for you nerds: no, still not right. 74. A, Orbit. Fat from subcutaneous, mesenteric, and retroperitoneal areas is used first in times of starvation. Last utilized is fat from the hands, feet, and orbit. 75. B, Increased satiety. Leptin is known as the “Satiety Hormone”, and with an increase in leptin concentration, your patient would likely exhibit increased satiety, decreased appetite & energy use. It doesn’t affect thirst, it’s related to adipose concentration (↑ Leptin = ↑ Adipose). 76. C, Dense irregular connective tissue . Sorry for the super low-yield douche question. Dense irregular: dermis, capsules, & submucosa. Dense regular: tendons, ligaments, & aponeuroses.

CARTILAGE & BONE 77. C, Type 1 Collagen composes 90% of bone matrix protein. 78. D, Osteopontin . Sorry for the douche question. Osteoproginitor cells are best known for producing osteoblasts, so I decided to ask a question that… wasn’t that. They can become osteoblasts, fibroblasts, chondrocytes, muscle cells, and adipocytes. Osteopontin is a multi-adhesive glycoprotein that promotes attachment of cells to the bone matrix. Totes not involved. 79. B, Osteoclasts derive from mononuclear hematopoietic stem cells (MHSCs). See above. 80. A, Collagen Type I . 81. C, Lacuna . 82. B, Osteoblasts initiate calcification of bone & respond to mechanical stimuli to mediate bone remodeling and growth. 83. C, Smaller are osteocytes in comparison to osteoblasts cause they shrink. 84. C, Gap junctions . Random little tidbit in the notes I have a feeling he’ll whip out of nowhere. 85. B, Osteoblasts; Osteoclast . 86. A, Carbonic anhydrase . 87. B, Interstitial lamellae → remnants of previous concentric lamellae . Compact bone → composed of concentric lamellae (A), Volkmann’s canals → tunnels for blood vessels & nerves that travel (C), and Spongy bone → arranged in trabeculae (D). 88. D, All of the above . It doesn’t have an organized lamellar appearance fo sho, known as “woven bone.” 89. D, Matrix becomes mineralized and trapped osteoblasts become osteocytes. Osteoprogenitor cells (A) are the result of condensed mesenchymal cells, not the other way around; Osteoprogenitor cells differentiate into osteoblasts (B), and osteoblasts secrete unmineralized bone matrix (C). 90. A, Length ; Width. Interstitial growth increases the length of cartilage, and appositional growth increases the width of cartilage. 91. B, Diaphysis. Primary ossification centers are the site where bone begins to form in the diaphysis of a long bone. 92. B, Epiphysis, just postpartum . Secondary ossification centers form in the epiphysis shortly after birth. 93. C, Epiphysis . Epiphysis is the the proximal end of a long bone where metabolically active chondroblasts are. 94. C, Z/o Reserve Cartilage → Z/o Proliferation → Z/o Hypertrophy → Z/o Calcified Cartilage → Z/o Resorption . 95. B, Growth Hormone promotes bone growth via IGF-1 → chondrocyte division. 96. B, Growth Hormone excess in children causes gigantism, and in adults causes acromegaly (thickening of bones instead of lengthening).

97. D, A & B. Testosterone stimulates osteoblasts and epiphyseal plate growth. 98. C, Osteoporosis . Menopause causes a deficiency of estrogen. Estrogen inhibits osteoclast apoptosis & induces osteoclast apoptosis. Therefore, post-menopausal women have an increased risk of osteoporosis. For you super nerds: no, osteomalacia still isn’t right. Osteoporosis causes a reduction in the mass of bones, sure, but two main things: one, osteoporosis has to present with a fracture (which then induces the reconstruction and remodeling of the bones) and is specifically linked with estrogen deficiency in women. Osteomalacia is less common and occurs when the bone is inadequately mineralized; they both exhibit bone loss, but osteomalacia is described as a “softening of the bone” rather than the brittle bones of osteoporosis. 99. G, B, C, & D. All of the statements minus (A) are correct. PTH is secreted by the parathyroid glands, while calcitonin is produced by C cells of the thyroid. 100. E, Contains Type II collagen. Important for ↓ friction in joints. 101. D, does not calcify with age. Hyaline cartilage does. 102. C, Contains Type I collagen . IV discs, pubic symphysis, etc. Shock absorber. 103. B, stimulates collagen production . Also stimulated by GH, Thyroid hormones, & testosterone. 104. F, inhibits collagen production . Also inhibited by estradiol (estrogen). 105. A, adjacent to chondrocytes, stains dark blue . Answer choice (G) describes the interterritorial matrix.

MUSCLE 106. B, C, E. 107. C, F. A* → I think they are fast twitch, I need confirmation re: Austin. 108. A, D, F. 109. C, Z ; Z . A sarcomere is defined from Z line to Z line. Also, A & I are bands (A). 110. C, the thin filament contains both the I and A bands . The I band is the thin filament when stretched (A), the thick filament contains muscle myosin II (B), and the M line is in the center of the sarcomere (D). 111. D, Ca++. Terminal cisternae at the ends of the network function as Ca++ reservoirs, and T tubules are invaginations of the plasma membrane that allow for regulation of Ca++. 112. B, P i = inorganic phosphate is released when Myosin II binds to Actin, which triggers the power stroke. 113. C, Acetylcholine . The motor unit is the neuron + innervated muscle fibers. 114. D, All of the above . Sorry for the douche question. In skeletal muscle, muscle fibers are arranged in fascicles, which are surrounded by endomysium. Perimysium surrounds individual fasicles. Cardiac muscle also has endomysium as connective tissue. 115. D, Slow and prolonged . 116. A. Can regenerate . Satellite cells are myogenic precursor cells, which are normally quiescent; they proliferate and produce myoblasts after injury to regenerate muscle. 117. D, Are replaced with fibrous connective tissue. No stem cells in the heart, bitch. Make sure to tell the next person who breaks your heart that little factoid. 118. C, Relies upon mature cells to proliferate. Smooth muscle progenitor cells → undifferentiated mesenchymal cells → mature cells can proliferate. 119. B, Tunica media. Just wanted to throw another tunica in there re: D. 120. B, Tunica media. Tunica intima is the innermost layer that lines the blood vessel. Tunica adventitia interacts with other tissues. See 119 for D. 121. A, Muscular arteries have a more prominent internal elastic membrane than large elastic arteries. Large elastic arteries have elastic fibers (A), muscular fibers have lots of smooth muscle (C), and large elastic arteries contract to maintain BP during diasystole (D) (side note: both muscular and large maintain BP). 122. C, The presence of a sphincter . Metarterioles have an incomplete layer of smooth muscle, but has a sphincter which controls blood flow into capillaries. 123. D, Can act as stem cells , specifically precursors to endothelial and smooth muscle cells. 124. A, Venules only have a tunica intima composed of epithelium and pericytes. 125. B, Subendocardium contains the heart’s electrical conduction system. Endocardium contains the endothelium & underlying connective tissue (A), the myocardium contains the cardiac muscle (C), and the epicardium contains CT, adipose, blood vessels & nerves for heart (D). 126. D, Receive impulses in the terminal portion . SA Node generates electrical signals (A), AV node receives impulses (B), the Bundle of His transmits the impulses to the ventricles (C).