Exam 5: BIOD 351/ BIOD351 Module 5: Pharmacology | Latest 2025/ 2026 Update | 100 OUT OF 100 |Questions and Verified Answers | GRADED A – Portage Learning.

Exam 5: BIOD 351/ BIOD351 Module 5: Pharmacology | Latest 2025/ 2026 Update | 100 OUT OF 100 |Questions and Verified Answers | GRADED A – Portage Learning. Exposing an embryo to cyclopamine early in development is most like to impact the anatomic structures derived from _________________. - ventral midline of the posterior region. - dorsal midline of the anterior region - dorsal midline of the posterior region. - ventral midline of the anterior region - ventral midline of the anterior region LEC 5.1 Slides 12 & 13 SHH is highly expressed along the VENTRAL MIDLINE in ANTERIOR REGIONS of the embryo. SHH pathway mutations or environmental manipulations lead to varying degrees of: 1) Midline patterning defects 2) Cleft palate/lip 3) Cyclopia* *(which was seen to affect pregnant goats when they eat corn lily plants known to have cyclopamine and jervine) Which of the following congenital heart defects is most commonly caused by disruption of the cardiac neural crest cells? - Persistent Truncus Arteriosus - Atrial Septal Defect - Tetralogy of Fallot - Ventricular Septal Defect - Persistent Truncus Arteriosus LEC 5.3 Slides 4-5 The cardiac neural crest (they migrate down and populate the aortic arch, arteries, etc) contributes to the SEPTA that separates the TRUNCUS ARTERIOSIS into the pulmonary artery and aorta. textbook: "Mutations of the Pax3 gene result in fewer cardiac neural crest cells, which in turn leads to persistent truncus arteriosus (failure of the aorta and pulmonary artery to separate) as well as to defects in the thymus, thyroid, and parathyroid glands (Conway et al. 1997, 2000)." NIH: "Conditional inactivation of Dgcr8 in neural crest cells, results in a variety of cardiovascular defects, including persistent truncus arteriosus, interrupted aortic arch, aberrant origin of the right subclavian artery and ventricular septal defect (Chapnik et al., 2011)." In the hemogenic endothelium model of hematopoiesis, the source of the adult hematopoietic stem cells (HSCs) are which of the following? - Hemogenic endothelial cells of the aorta - Hemangioblasts of the blood islands - Hemangioblasts in the yolk sac - Angioblasts in the mesoderm - Hemogenic endothelial cells of the aorta LEC 5.2 Slide 2 ^ Briefly discussed hematopoietic stem cells (HSCs) and how they contribute to the formation of blood islands. Mote, the question is asking for the source of hematopoietic stem cells (HSCs) themselves. See below: textbook: "FIGURE 18.22 Pathway for hematopoietic stem cell formation. (A) In the developing mouse, hematopoietic stem cells arise from the hemogenic endothelium of the aorta." If you treated embryos with a Notch inhibitor, how would this affect the specification of venous and arterial endothelial cells? - All endothelial cells would be venous - No effect, normal specification. - All endothelial cells would be arterial - No endothelial cells would be specified. - All endothelial cells would be arterial pretty sure this is wrong but idk??? - regraded to be correct -- possible explanation: The Notch signaling pathway plays a crucial role in determining the fate of cells during embryonic development, especially in the specification of venous and arterial cells. When a Notch inhibitor is applied to embryos, it blocks the Notch signaling pathway, preventing the normal funcitoning Notch receptors and their downstream signaling events. The inhibition of Notch signaling leads toa specific outcome in the specification of endothelial cells. In the absence of Notch signaling, all endothelial cells tend to adopt an arterial fate. (?) If Vascular Endothelial Growth factor (VEGF) is knocked out in mouse embryos which of the following is most likely responsible for the phenotype? - Cardiogenic mesoderm will not be specified - Hemangioblasts will not be specified in the splanchnic mesoderm. - Blood vessels will not recruit pericytes. - Hemangioblasts will not differentiate into angioblasts. - Hemangioblasts will not differentiate into angioblasts. never learned in lecture; it's a guess???? -- update: correct During embryonic development the vessels of the vasculature must correctly connect. Which of the following molecules mediate this event? - SHH and Smoothened - Ephrin B2 and Eph B4 - Notch1 and Jagged1 - Wnt3 and Frizzled - Notch1 and Jagged1 UPDATE: THIS ANSWER IS APPARENTLY WRONG: correct answer: - Ephrin B2 and Eph B4 (^ this was not covered in the slides or the textbook) textbook: "Ephrins Juxtacrine ligands. Binding between an ephrin ligand on one cell and an Eph receptor on an adjacent cell results in signals being sent to both cells. These signals are often those of either attraction or repulsion, and ephrins are often seen directing cell migration and defining where cell boundaries are to form. As well as directing neural crest cell migration, ephrins and Eph receptors function in the formation of blood vessels, neurons, and somites." textbook for Notch :/ "Though the apically situated cell bodies of B cells can be quite a distance from blood vessels, their basal endfeet are intimately associated with the vasculature (see Figure 5.12). As discussed earlier, Notch signaling is fundamental in controlling B1 cell quiescence. Notch receptors in the B cell's endfoot bind to the Jagged1 (Jag1) transmembrane receptor in endothelial cells, which causes Notch to be processed into its NICD transcription factor, and B1 cell quiescence is maintained as a result (Ottone et al. 2014)." In the bone marrow stem cell niche, signaling regulates self-renewal and regulates maintenance of stemness or plasticity. Use the letters on the diagram to fill in the blanks. - D, C - B, E - A, B - E,D - D, C ??? (regraded to be correct but still not sure) Which of the following organs is not derived from the embryonic gut tube? - kidneys - lungs - liver - pancreas - kidney LEC 5.4 Slide 3-11 Bipotential gonads arise as thickening of intermediate mesoderm adjacent to the developing kidney - this is the genital ridge. Wnts play an important role in promoting EMT in developing neural crest progenitors. What is the receptor for secreted Wnts? - Patched - Lunatic fringe - Smoothened - Frizzled - Frizzled LEC 1.4 slide 10 LEC 1.4 Quiz Q!! Copy & paste :) You are examining embryos at different stages of development. The embryos harbor a Wnt1:Cre allele that has excised the STOP cassette in Rosa26 LacZ reporter (Wnt1:Cre; R26-loxp-STOP-loxp-LacZ). What cells do you expect to NOT see LacZ positive? Choose the best answer - melanocytes - pharyngeal arches - glial cells - hemangioblasts - glial cells ??? LEC 5.1 Slide 3 and LEC 5.3 Slide 2 Lac + is seen in the Pharyngeal Arches and the Cardiac Crest possible answer from the internet: Hemangioblasts: Hemangioblasts are precursor cells capable of differentiating into both blood cells and endothelial cells that line blood vessels. The Wnt1:Cre; R26-loxp-STOP-loxpLacZ genetic system is expected to activate LacZ expression in cells where the Wnt1 promoter is active, including hemangioblasts. Therefore, in embryos harbouring the Whti. Ile allele, hemangioblasts would be expected to show LacZ expression and appear LacZ positive. Neural crest cells, which derive from the dorsal lip of the neural tube, contribute to skeletal structures such as the skull. - True - False - True LEC 5.1 Slide 6 LEC 5.1 quiz Q: Q: The craniofacial skeletal tissues are primarily derived from a combination of ___________ and _________? A: Cranial neural crest, mesoderm Multiple dropdowns. Choose the best answer for each. The cardiac mesoderm forms _______________ to the hemangiogenic mesoderm, and this is attributed to the inhibition of ___________. OPT #1: ["anterior", "posterior"] OPT #2: ["Notch", "Fgf8", "Shh", "Wnt"] OPT #1: anterior OPT #2: Wnt LEC 5.2 Slide 4 * Wnt must FIRST be inhibited in order to progress down the "anterior"/cardiac mesoderm pathway. All heart cells derive from a common progenitor referred to as the ___________. Fill in the blank with the best answer. - definitive endoderm - precardiac mesoderm - hemangioblasts - bipotential myogenic progenitor - precardiac mesoderm LEC 5.2 Slide 5 All heart cells comes from a common progenitor = precardiac mesoderm! Multiple dropdowns. Choose the best answer for each. The primary heart field only contributes to the ____________ of the 4 chamber heart, but is important for ________________. OPT #1: ["left atrium", "aorta", "right ventricle", "left ventricle"] OPT #2: ["adding cells to both ends of the heart tube", "generating the endocardial cushion", "forming the initial scaffold", "contributing to the outflow tract"] OPT #1: "left ventricle" ? (not correct? 0.5/1 pts) OPT #2: "adding cells to both ends of the heart tube" LEC 5.2 Slide 11 The first heart field forms the initial scaffold, the cardiac primordial, and the initial linear heart and will become the ventricle. The second heart field is now also specified and these cells add to either end of the primordia. The linear heart tube consists of endocardium and myocardium. At the time of fusion, the cells are __________. Complete the sentence. - infiltrated with neural crest cells - differentiated - looped - specified - differentiated UPDATE: INCORRECT (correct answer unknown) LEC 5.2 Slides 9-11 Because at the time of fusion, the cells in the linear heart are differentiated, meaning they have already specialized into their respective cell types, such as the endocardial cells and myocardial cells. Differentiation is a key process in development where stem cells or progenitor cells transform into specialized cells with specific functions. A loop is not the answer because it is a process that occurs after the formation of the linear heart tube during cardiac development. As the heart tube elongates and it forms loops that eventually give rise to the four chambers in the mature heart. Infiltrated with neural crest cells is a process that occurs during cardiac development, but it happens slightly later than the fusion of the linear heart... ________ produces four chambers in the heart. Choose the best answer. - Specification - Septation - Dextrocardia - Looping - Septation LEC 5.2 Slides 9, *17, & 19 On slide 17: "Septation creates four distinct chambers of the heart." Cardiac neural crest cells contribute to septa that separate the trunk arterioles into the pulmonary artery and aorta, such that lack of these neural crest cells can lead to __________. Complete the sentence with the best answer below. - increased electrical activity - thickening of the artrial wall - mixing of oxygenated/de-oxygenated blood - no effect - mixing of oxygenated/de-oxygenated blood LEC 5.2 Slides 21, 23-24 Defects of the endocardial cushions will contribute to many abnormalities including atrial and ventricular septal defects; this is just a fancy way of saying that the septum will cause the ventricles to mix their blood. Defects of the cushions and septum will also cause abnormalities to the great vessels (e.g., transportation of great vessels and Tetralogy of Fallot). ***Defects are often associated with CRANIOFACIAL DEFECTS! This is, when looking at the root-cause, defects of the neural crest composition, etc. ------------------- Cardiac neural crest cells contribute to septa that separate the trunk arterioles into the pulmonary artery and aorta, such that lack of these neural crest cells can lead to mixing of oxygenated/de-oxygenated blood. The pulmonary artery is responsible for carrying deoxygenated blood to the lungs, while the function of aorta is to carry oxygenated blood throughout the body. Multiple dropdowns. Choose the best answer for each. Melanocytes derive from ______________________ and migrate __________________. OPT #1: ["neural crest cells", "notochord cells", "definitive endoderm", "sclerotome"] OPT #2: ["dorsolaterally", "above the epidermis", "ventrally", "through the somite"] OPT #1: "neural crest cells" OPT #2: "dorsolaterally" LEC 5.3 Slides 10-11 The CRANIAL TRUNK DORSOLATERAL NEURAL CREST generates melanocytes (which generate pigmentation). In the periphery, arteries are commonly aligned with __________. Fill in the blank. - satellite cells - lymph nodes - peripheral nerves - muscle - peripheral nerves ?? update: correct Which (putative) cells of the endoderm are specified by the highest levels of Wnt and BMP? - thyroid - esophagus - hindgut - liver - lung - pancreas - hindgut LEC 5.2 Slides 4, 13 LEC 5.5 Slide 9! textbook: Those in the posterior region are exposed to high levels of Wnts, BMPs, and FGFs and become midgut-hindgut (MG-HG) cells that generate the intestines.