Tutor profile: Jodi L.
Subject: Biomedical Science
What are some risk factors for developing breast cancer?
When cancer forms in the cells of breast tissue, it is called breast cancer. It is a relatively common form of cancer in women, and there are varying forms depending on the location of the initial location of abnormal cells (Mayo Clinic, 2021). These cells typically accumulate into a lump, and can spread beyond the breast tissues if untreated. There is some understanding of risk factors when it comes to cancer in general, and breast cancer specifically which has gotten a remarkable amount of funding and research attention, though there are still some aspects of risk factors that could be better understood (Mayo Clinic, 2021). Two genes, breast cancer gene 1 and 2, are genetic indicators that greatly increase the possibility of a woman developing breast cancer and ovarian cancer (Mayo Clinic, 2021). Studies have also shown that breast cancer risk correlates to the duration of estrogen exposure in a woman’s life, in other words a woman who gets their period early or starts menopause late, will have an increased risk, and the same goes for other conditions of estrogen exposure (Marieb & Hoehn, 2019). There are some other risk factors to developing breast cancer as well. Women are more likely than men to get breast cancer, and the older one ages the higher their likelihood of developing many different forms of cancer (Mayo Clinic, 2021). Those that have experienced different forms of breast conditions including but not limited to previous occurrences of breast cancer, are at higher risk than those who have not (Mayo Clinic, 2021). Obesity, radiation exposure, and alcohol consumption are all breast cancer risk factors as well (Mayo Clinic, 2021).
Define nitrogen balance. List three factors that might lead to negative nitrogen balance and three that might result in positive nitrogen balance.
In its most simple form, nitrogen balance can be distilled down to the difference between the input and output of nitrogen in the body. Proteins are a unique macromolecule compared to fats and carbs as they contain nitrogen (Macdonald). The protein we ingest has a value of nitrogen, the body then uses this protein, and the nitrogen is excreted through primarily urine via urea. When someone is taking in more nitrogen than they are excreting i.e. using, they are in a state of positive nitrogen balance. And vice versa if someone is excreting or using more nitrogen than they are taking in, they are in a state of negative nitrogen balance (Marieb & Hoehn, 2019). For example, when a child is growing, they may have a relatively high protein intake, and when the nitrogen in the protein may be used in building new tissues or facilitating growth processes, leading to a lower value of released nitrogen, in other words, positive nitrogen balance. Similarly a pregnant women may show similar trends as the nitrogen is being incorporated into the fetal tissue, or even when someone is recovering from illness or injury, they may too be experiencing positive nitrogen balance (Marieb & Hoehn, 2019). Negative nitrogen balance, on the other hand, may appear in athletes who are cutting calories too harshly, or overtraining, wherein the athletes catabolic activities (ones which break down proteins sending nitrogen to the urea), are happening more frequently than anabolic activities (ones where the nitrogen is being incorporated into tissues as they are built/rebuilt) (Macdonald). Other scenarios that lead to negative nitrogen balance are generally malnutrition related, whether it be starvation, stress induced starvation, or low quality protein sources which do not contain essential amino acids, the low intake of nitrogen is easily overpowered by the output (Soeters, 2015).
Explain the action of drugs like sildenafil (Viagra) on the male reproductive system.
A man’s penis changes based on his state of sexual arousal, and drugs like sildenafil can aid in the transformation that the penis undergoes when a man goes from not being aroused to being aroused. When not aroused, a penis is flaccid, this is created by constricted arterioles that bring blood to the tissues in the penis that enable it to become erect (Marieb & Hoehn, 2019). This erectness of the penis is triggered by a parasympathetic response that naturally occurs during sexual arousal. Nitric oxide is released as a product of the parasympathetic response, this chemical relaxes penile tissue, thereby dilating the arteries, allowing blood to flow into the penis transforming what was once flaccid to erect (Marieb & Hoehn, 2019). Simultaneously the corpus cavernosa which is expanding from the influx of blood, compresses the veins of the penis, allowing the penis to remain engorged as it prevents the blood from flowing back out (Marieb & Hoehn, 2019). For almost half of men over the age of 40, erectile dysfunction, or the inability to attain or maintain an erection, is a common problem. Multiple influences such as drug induced altered states, psychological blocks, vascular issues, and nervous system issues, can be the impetus that impairs the cascade of events leading to a maintained erection. Nitrous oxide, being an essential driver in the process of becoming erect, can be a very effective mechanism to target with the intention of overcoming erectile dysfunction, and that is exactly what sildenafil and other similar drugs do, they enhance the effect of nitrous oxide, which is to relax the muscles in the penis, enabling men to overcome erectile dysfunction when necessary (Marieb & Hoehn, 2019).