Tutor profile: Alexandra O.
Subject: Biomedical Science
Fiona was born and raised in San Diego, CA. She has just flown into Denver, CO to start college next Spring. She is very excited to experience the mountains, and decides to go for a sunset hike at Pikes Peak later the same day. You are a Colorado native, and don't want Fiona to faint, pass out, or potentially die by taking this hike too soon. Explain to Fiona why she should wait at least 3-4 days before hiking. Be sure to think of the following: 1) Explain how her hemoglobin might react differently than yours. Think about PO2. 2) Explain why Fiona would experience alkalosis if she took the hike. 3) Using the carbonic anayhydrase equation, explain why you would recommend she drinks lots of water before hiking?
1+2) Her Hb would hold on to O2 more than at sea level. Her exchange of CO2 would be greater, and since CO2 will stay longer in the blood stream than O2 (since that will diffuse easily), then she will need to hyperventilate to "blow off" the CO2 to push the equation to the left. When pushed to the left, it will cause a decrease of H+ protons. This will increase pH and make her blood more alkaline. 3) By drinking more water, you can push the equation back to the right to help equilibrate the pH.
Compare and contrast steroid versus peptide cell signaling as it pertains to the cell membrane of a human cell.
Cells contain a phospholipid bilayer that encapsulate all of the cell's organelles and structures. Within this bilayer, many proteins are poking out into the intracellular space as well as the extracellular space. These proteins are waiting for their target protein (such as a peptide hormone) to lock into their receptor to stimulate some sort of response. This response can be a cascade of intracellular events that may lead to the production (or ceasing to produce) related proteins and/or other cell signaling molecules. This response is typically very quick, and involves many contributing enzymes or modulators to help progress the intended response. This is in contrast to a steroid response. Within the phospholipid bilayer, there are a sea of phospholipids that are similar in structure to steroid hormones. Thus, when steroid hormones find their target cell, these steroids can simply diffuse from the extracellular space and enter into the intracellularspace. Once they are within the cell's cytoplasm, they are then looking for their intended receptor. This receptor could be within the cell's cytoplasm, or it may be within the cell's nucleus, which would involve a second diffusion into the intra-nuclear space. Once the steroid finds its receptor and binds, the production of the intended protein or cell signaling molecule can be made. Since this entire process depends on the steroid bumping into its intended cell and them diffusing into the cell, the process is much longer, and the recruitment of other cellular structures is not as common.
Your patient has been admitted to the emergency room with an occipital injury from an industrial saw. He has lost a significant volume of blood. What effect has this blood loss likely had on his blood pressure, and why?
Due to the immediate loss of systemic blood volume, one would expect blood pressure to dramatically decrease before any cardiovascular systems can recover. In order to explain the relationship between blood volume and blood pressure, an understanding of cardiac output is important. Cardiac output (CO) is one of two primary contributors to systemic blood pressure. CO is a measurement of how effective the heart is at moving blood out of the aorta and into the systemic capillaries. CO is measured by multiplying heart rate (HR) by stroke volume (SV). HR is primarily affected by neurological and hormonal factors, as is SV, however SV is also directly affected by venous return of blood. Venous return is defined as the amount of blood that returns to the right atrium during the cardiac cycle (ventricular and atrial diastole). If less blood is available to return to the right atrium, perhaps due to hemorrhagic loss, then SV is minimized. SV is defined as the amount of blood ejected during a single left ventricular contraction. Since SV is proportional to CO, and if SV is less due to blood loss, then we would expect CO to also be less. If CO is less, then systemic blood pressure will also be dramatically decreased.
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