SAQ FR

Question 1

In CHF, the heart fails to efficiently pump blood around the body. The kidneys sense the decreased blood flow. The liver and glands release hormones to try to enhance blood flow by retaining more water in the body. The increased water volume in the blood vessels puts more stress on the heart, which further reduces blood flow to the kidneys and other organs.
A. Do you think the example above is a description of a negative feedback loop or a positive feedback loop? Why? What evidence supports your answer?

Answer 1

• I think that this is an example of a positive feedback loop.
• Despite the body enacting counter measures, such as the release of hormones to enhance blood flow, the effect of CHF is still being amplified by the body’s reaction. - - The positive feedback loop is clear in the fact that the body’s response results in the increased water volume that stresses the heart and reduces blood flow further.

Question 2

In the CHF example what is the sensor: In CHF, the heart fails to efficiently pump blood around the body. The kidneys sense the decreased blood flow. The liver and glands release hormones to try to enhance blood flow by retaining more water in the body. The increased water volume in the blood vessels puts more stress on the heart, which further reduces blood flow to the kidneys and other organs.

Answer 2

The kidneys are the sensor, as they are the first to recognize the decreased blood flow

Question 3

What is the effector in this example: In CHF, the heart fails to efficiently pump blood around the body. The kidneys sense the decreased blood flow. The liver and glands release hormones to try to enhance blood flow by retaining more water in the body. The increased water volume in the blood vessels puts more stress on the heart, which further reduces blood flow to the kidneys and other organs.

Answer 3

The liver and glands are the effectors in this example. After the imbalance is sensed. The liver and glands release hormones to try to fix the issue.
- It is the effector because it brings around the change that can alter the body’s condition

Question 4

How do the respiratory and cardiovascular systems cooperate to deliver oxygen to body cells and remove carbon dioxide from the tissues

Answer 4

• The process starts with the respiratory system, with the inhalation of oxygen that filters into the lungs.
• Once in the lungs, it goes through the bronchi into the bronchioles, and enters the alvioli
• The alvioli are little sacs on the end of the bronchioles that are the site of gas exchange between air and blood. - - Oxygen rich blood is then taken to the heart through the pulmonary vein
• the cardiovascular system then takes over and it enters the right side of the heart, going through the left atrium, bicuspid valve, and left ventricle, before making to the aorta to be spread to the body
• red blood cells contain hemoglobin, which has an iron molecule in the middle, allowing four oxygen to attach and be carried throughout the body.
• oxygenated blood then gets pumped to through arteries to parts of the body
• after the cells use the oxygen, they produce carbon dioxide, which is transported by the erythrocytes through veins back to the heart, where it goes through the inferior vena cava, right atrium, tricuspid valve, right ventricle, pulmonary valve, pulmonary artery and back to the respiratory system, the lungs to be re oxygenated and start the cycle again

Question 5

Agree or disagree:
“Evolution is a biological process that aims
to improve an individual organism over long periods of time.”

Answer 5

Disagree. Evolution does not take effect through one individual, but through generations of individuals. This process is not a proccess of improvement but of random genetic mutations that allow some to be better suited for their environment than others.

Question 6

Fever is a failure of homeostasis

Answer 6

Disagree. Fever is evidence that homeostasis is working. When a foreign object enters the body, it will respond through negative feedback by increasing the internal temperature to try to remove it.

Question 7

Organisms evolve through survival of the fittest

Answer 7

Disagree. Organisms evolve through reproduction of the fittest. This means that it it not necessarily the strongest that succeed, but the ones that are most well adapted through random gene mutation, that can reproduce and pass down that dna.

Question 8

Before taking bio 2 I thought obesity was caused by exercise and low physical activity

Answer 8

I now understand that obesity is a complex combination of risk factors, the most important of which is evolution. Early in out history, our ancestors frequently went through periods without food. Random gene mutation shaped our bodies to hold as much fat as possible to prepare for these events. Now, due to our sedentary lifestyle and frequent access to food, this evolutionary trait makes it very difficult to lose weight. For type 2 diabetes, this comes in the way of increased unhealthy food intake and insulin resistance after an excess in glucose molecules cannot make it into fat cells. Leptin and insulin resistance make it very difficult for people to lose the weight that they quickly gain.

Question 9

Before bio 2 i thought there was one scientific explanation for the origins of life

Answer 9

Now I understand that there are many.
1. This includes the RNA world theory, which posits that RNA was able to replicate because it is made up of nucleotides that can arise spontaneously. The storage of those cells inside a vesicle, or lipid bag, made natural selection possible and eventually the existence of a DNA/ rna cell possible.
2. Thermal vents at the bottom of the oceans provided all the necessary elements to synthesize organic monomers
3. Some comets and meteorites have organic molecules that could have provided the building blocks for the chemical origin of life

Question 10

What is one thing you learned in biol 2 that will someday help you make a decision in your daily life

Answer 10

Learning about cardiac health will I’m sure continue to impact my actions as I age. I already work out frequently and eat healthily, but that only becomes more important with age. Knowing that exercise helps increase the flexibility and strength of blood vessels, and that smoking increases risk for plaque, will factor into my decisions down the line.