Sheep Heart Dissection Questions

1. The pericardium serves to provide lubrication for the heart and protects against infection. It is the outermost layer of the heart.

2. The biggest difference between veins and arteries is that arteries take blood away from the heart, while veins bring blood to the heart. Veins have valves that prevent back-flow of blood. The veins also have thinner walls. Arteries have thick, muscular walls.

3. The auricles are like a balloon attached to the atria. They fill up with blood also, increasing the holding capacity of the atria.

4. The external structure gets narrower as we go down the heart. The atria are wider than the ventricles. This gives the appearance of the upside down triangle sort of shape.

6.

7. The chordae tendinae prevent the valve from reopening in response to the pressure lowering in the atrium during ventricular systole. The pressure in the atria becomes much lower, and because things naturally go from high to low concentration, the chordae tendinae and papillary muscles prevent this from happening.

8. The valve is a whitish color, different in texture from the endocardium lining of the chambers. This valve is bigger than the semilunar valves and the tricuspid valve.

9. Semilunar valves prevent back-flow from arteries back into the ventricles during ventricular diastole, and they also maintain the pressure in the arteries so they can effectively push the blood where it needs to go.

10. a) Blood can become backed up in other parts of the body if there is valve disease, causing swelling. If the blood can't get pumped back into the heart, it becomes stuck. b) Left side valve disease can cause tricuspid regurgitation.

11. The chordae tendinae of the bicuspid valve are super stringy, pulled taut with probe causes valve to be open. You can see through the aorta, or where the aortic arch would be.

12. The right side of the heart receives oxygen deprived blood and sends it to the lungs for reoxygenation. Conversely, the left side of the heart receives the oxygen rich blood from the lungs and sends it to the rest of the body through the left ventricle.

13.

Unit 3 Reflection

Review: This unit was about cardiovascular health, and how to maintain said health. The circulatory or cardiovascular system is comprised of three parts, the heart, the blood, and the blood vessels. The heart is the basis of operations: all blood in the body comes back to the heart to be reoxygenated and resent back to the body. The structure of the heart plays an important role in its function: four separated chambers operate through contraction and relaxation, called systole and diastole respectively, which pushed the blood out of arteries, particularly the pulmonary arteries and the aorta. The right side of the heart gets deoxygenated blood and sends it to the lungs, and the left side gets oxygenated blood and sends it to the body. The blood itself is comprised of different types of cells and fluid: red blood cells, white blood cells, plasma, and platelets. Blood vessels, like arteries, veins, and capillaries, transport the blood where it needs to go in the body.
Heart disease is caused by atherosclerosis, triggered by excess sugar, excess polyunsaturated fats, excess omega-6, and damaged blood vessels. Focusing on the latter, blood vessel damage occurs when LDL, the "bad cholesterol," sticks to the walls of the blood vessels, lodging itself in the walls. When this occurs, an inflammatory response is triggered, which results in a counterproductive process of creating "foamy" mast cells, creating a plaque in the walls. This plaque can break, which causes a blood clot. This blood clot can either block the blood in the same blood vessel, or break off and travel further in the body, where it clogs up there and causes a heart attack or a stroke. A stroke only occurs in the brain, and can be very fatal. Every minute during a stroke, 2 million blood cells die, making the treatment for strokes very time-sensitive. To promote your own cardiovascular health, maintain a healthy diet, exercise, do not smoke or drink alcohol in excess, and know your family history of hypertension.
Reflect: I am still struggling with differentiating between the different white blood cells. I struggled with the case study activity, which is concerning because that question format is a large portion of the test. Also, without my group members to collaborate with, I probably cannot identify structures on the sheep heart alone. If I had to look at another sheep heart that wasn't the one I was familiar with and hands-on with, I would be beyond confused.
Considering that it is currently past midnight and I'm still mid-study session, my sleep goal from last semester is not going so well. However, I was able to catch up on some of the midterm-stolen sleep over the weekend! These couple of weeks are extremely tough as many deadlines overlap. Most of the units in our various classes tend to end on a similar schedule, meaning that we have weeks of "chill" time and weeks of testing mayhem. This makes it hard as a student to allocate my time to all of my classes appropriately, and maintain my work schedule. In general, I'm a focused person, so I know that it's not lack of focus contributing to any poor marks, but rather just lack of time or biological ability to function. I do try as hard as I can.
Going back to the unit, a surprisingly fun activity was the dissection! I entered the activity with a negative mindset, intending to only take notes, but I was soon "two-glovin' it" and fully immersed, poking and prodding the heart with gusto. I'm happy with myself for pushing my learning to another level, despite my prior reservations.

Mid-Unit Summary

This unit, we are learning about the circulatory system. The heart of the circulatory system is, metaphorically and literally, the heart itself.
Let's look at the structure of the heart. Comprised of four chambers, the heart is hollow to allow for blood to be pumped in and out. The chambers are the left ventricle, right ventricle, left atrium, and right atrium. The atria are the upper chambers, and the ventricles are below. The right atrium receives oxygen deprived blood. The left atrium receives oxygen rich blood. The right ventricle pushes blood out of the heart to the lungs. The left ventricle discharges blood to the body. There are valves in the heart that prevent back-flow of blood: the sublunar pulmonary and aortic valves, the tricuspid valve, and the bicuspid valve. The heart sounds we hear are the slamming of these valves shut.
The circulatory system branches from the heart to the entire body. The 3 components are the heart, the network of tubes, and the blood. Blood flows in veins to the hearts, or arteries away from the heart. Small arteries are called arterioles, and small veins are called venules.
Blood itself is comprised of 55% plasma and 45% cellular stuff. The cellular stuff is red blood cells, white blood cells, platelets, and others. The white blood cells are neutrophils, basophils, eosinophils, lymphocytes, and  monocytes. Platelets help blood clot. Red blood cells carry oxygen in the blood.
When there is an excess amount of LDL, the bad cholesterol, it sticks to artery walls, becoming a plaque, which can then rupture and cause a blood clot. Blood clots can lead to strokes and heart attacks, which are very deadly.

https://upload.wikimedia.org/wikipedia/commons/e/e0/Heart_diagram-en.svg
https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&ved=0ahUKEwiVstrt8PvPAhUQ9mMKHX-6A8QQjRwIBw&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FWhite_blood_cell&psig=AFQjCNG_kW_UUtA4aTszmYdRUT-yfK7fWA&ust=1477688519713371

Blood Pressure Lab

Systole is the pressure of the blood in the body when the heart contracts, while diastole is the remaining pressure when the heart is relaxed. To measure heart rate, you can use a blood pressure cuff and a stethoscope, but you can also use a timer and your fingers placed on the radial or carotid arteries. Blood pressure is measured with a blood pressure cuff and a stethoscope. When you measure a pulse, don't use your thumb because your thumb has its own independent pulse that you may feel. To use a blood pressure cuff, place the cuff, with no air, on the bicep area of the uncovered arm. Put the stethoscope end under the cuff, on top of your veins in the inside of your elbow. Close the valve on the cuff and squeeze the bulb until the meter of the sphygimomanometer says 150 mm/Hg. Gently release the air from the valve, listening for the first heartbeat. Take note of the number on the meter when you hear it. Continue releasing the air until you no longer hear the heartbeat, and take note of the number on the meter when you stop hearing the heartbeat. The first number recorded is the systolic number, and the second is the diastolic.

Chalk Walk

We crafted a masterpiece on the hallway floor. As you can see in the video, oxygen-deprived blood enters the heart from the upper body through the superior vena cava, and from the lower body through the inferior vena cava. The blood enters the right atrium, then goes through the tricuspid valve into the right ventricle after the atrium contracts. There, the blood goes to the lungs through the pulmonary valve and out the pulmonary arteries to be reoxygenated. From the lungs, blood reenters the heart through the pulmonary veins, entering the left atrium. Blood then goes through the bicuspid valve into the left ventricle, the largest and strongest chamber of the heart, and through the aortic valve to the aorta, where it is pushed to the rest of the body.

Unit 2 Reflection

This unit, we focused on health. But what exactly is health? In the beginning of the unit, our group-made definitions included keywords like "exercise" and "mental and physical health." As we learned in class, health is the measure of our body's efficiency and overall well being. Health can be thought of as a triangle, with the three sides of mental health, physical health, and social health. Mental health is how we think and cope with situations, and whether we suffer from mental illnesses or disorders. Physical health is our body's ability to function. Social health is how we react to others in our environment. Health can also be thought of as a columned building with 5 pillars: nutrition, exercise, sleep, stress, and social life. Each of these pillars is essential to the building's foundation, and if one pillar is skewed, the building is structurally weak and may collapse.

When our bodies are physically healthy, certain hormones known as the Big Four are doing their jobs correctly. The first of these hormones is insulin, the hormone that facilitates the movement of macro-nutrients into the cells and regulates the blood glucose levels. In western society, we tend to "overcarbsume," which can lead to insulin resistance, a dangerous condition that affects the body's ability to detect insulin's presence. The second hormone is leptin, which tells the brain how much fat there is on the body. It also regulates the energy intake and expenditure, controlling how much we eat and feel the need to get moving. When we have a lack of fat, no leptin is released, which tells the brain to eat and retain fat. When we have an excess of fat, leptin is released, which tells the brain to stop eating and increase activity. The third hormone is glucagon, which allows access to the body's glycogen storage for energy. This can be stimulated by low blood sugar, stress, or an intake of protein. The last hormone is cortisol, not so affectionately known as the "stress hormone" because it is prevalent in response to stress. It raises blood pressure by stimulating glycogen breakdown, and can be dangerous if elevated for long periods of time.

Now, to focus back on the pillars of health, let's look at nutrition. A nutrient is a substance in food that exerts a biological function and is necessary to live. The classes of different nutrients are carbohydrates, lipids, proteins, minerals, vitamins, fiber, water, and phytochemicals. The amount of each nutrient needed varies. In order to maintain a healthy diet, follow these four rules: Adequacy, Moderate, Variety, and Balance. Always look for nutrient dense foods, which have lots of nutrients for relatively low calories. Carbohydrates in food can be simple (mono/disaccharides) like fruits, dairy, honey, sugar, syrup, and agave; complex (polysaccharides) like grains, legumes, and tubers; or fiber (soluble or insoluble) like whole grains, which is resistant to digestion and prevents constipation. For carbohydrates, choose fiber rich foods, limit foods with added sugar, choose a variety of fruits and vegetables, and half of your grains should be whole grains. Lipids in food can be saturated like coconut oil, butter, cheese, or lard; unsaturated like olive oil, avocado, nuts,or canola oil; or trans-fat like hydrogenated oils in processed/fried foods. There are 4 main types of fat in food, polyunsaturated fats (PUFAs), monounsaturated fats (MUFAs), saturated fats (SFAs), and trans-fats (TFAs). PUFAs like omega 3 help with brain and heart health, but too much omega 3 can lead to inflammation. MUFAs increase HDL, the good cholesterol. SFAs increase LDL, the bad cholesterol. TFAs increase LDL and decrease HDL, hardening the arteries. Limit your fat intake to 25-30%, choose low fat or fat free dairy, avoid trans-fats, and increase your intake of omega 3. Proteins in food account for the 9 amino acids that our bodies can’t produce and must obtain from food. They provide energy, repair things, transport and store molecules, increase immunity, and more. Eat high protein foods with low fat. Vitamins maintain growth and normal metabolism, act as coenzymes, and can be antioxidants. Water accounts for ⅔ of the body’s overall weight. We are dependant on water to survive, and will die without it in a few days. It regulates our body temperatures, lubricates joints, makes up saliva, and more. In general, drink either 6-8 glasses a day or half your bodyweight in ounces.

Now, we look at exercise. There are four types of exercise: aerobic, muscle strengthening, bone strengthening, and flexibility. Aerobic, known as cardio or endurance, works muscles as groups and increases the heart rate. Muscle strengthening works muscles against a force or a weight, creating tiny tears in the muscle that heal to strengthen it. Bone strengthening pits force on bones that promotes bone strength. Flexibility increases the range of motion, but should not be counted toward overall minutes of exercise. When we exercise, we rely on different metabolic pathways for energy throughout our workouts. First we use the phosphagen pathway for high power, short exercises, relying on creatine phosphate. Then we use the glycolic pathway for lower power exercise up to 10 minutes, relying on glycolysis until the lactic acid concentration in the body is too high. Then we use the oxidative pathway for exercise upwards of 10 minutes, relying on cellular respiration for energy.

Next, let’s look at sleep. Sleep is a sensory shutdown where we are no longer aware of our environment, and is reversible. There are 2 types of sleep that we cycle through each night, REM and Non-REM sleep. During REM sleep, pronounced “rem” and named for the binocularly synchronous “rapid eye movement” that occurs, the brain is very active and most of the body is paralyzed as we experience vivid dreaming, indistinguishable from reality until we wake up. In Non-REM sleep, the eyes roll slowly and independently, and the body is not paralyzed. The body has an internal biological clock called the Circadian Rhythm, controlled by the hypothalamus which dictates when certain biological processes, such as sleep, take place each day. Melatonin, the hormone secreted by the pineal gland and known as the “Dracula hormone,” causes you to fall asleep, while cortisol, the “stress hormone,” causes you to wake up. If you do not sleep an adequate amount, you amass sleep debt, which can lead to sleep deprivation, impaired performance, mood swings, hunger, etc. All sleep debt must be paid at some point.

Lastly, we shall look at the final pillar, stress. Stress is any event or demand that causes a predictable physiological response. Stress can be eustress, providing extra energy, momentum, and boosted productivity. But it can also be distress when it persists after the stressor is gone or persists daily. The first stage of stress is the alarm phase, or the “fight or flight” response. The body is ready for immediate physical activity. The second stage of stress is the resistance phase. Cortisol levels are high, and blood pressure and appetite are raised. The last stage of stress is exhaustion, where energy reserves deplete and feelings of lethargy raise. If this stage persists, death can occur.

At SHS, our sleep and stress pillars are very weak. We tend to pull all-nighters to finish assignments. A real-world application of what we learned is when my father was studied by various doctors to examine his sleep patterns, as he suffers from sleep apnea. Tethered to a plethora of wires and machines, he snored loudly on the dinky hospital bed. They concluded that his sleep apnea and snoring caused him to repeatedly slip in and out of deep sleep, preventing him from getting the full benefits of REM sleep. His espresso addiction suddenly made a lot more sense. He ended up attempting surgery for his deviated septum, but the surgery went poorly after they accidentally cut an artery in his neck and needed to fix that first. He still snores and relies on coffee, and is forgetful, cranky, and drowsy.

https://en.wikipedia.org/wiki/Food_pyramid_(nutrition)

https://commons.wikimedia.org/wiki/File:StressSymptoms.gif

https://en.wikipedia.org/wiki/Sleep_deprivation

https://en.wikipedia.org/wiki/Stress_(biology)

http://www.nhlbi.nih.gov/health/health-topics/topics/sleepapnea

Sleep Diary

The scariest part about the Sleep Diary activity was that I already knew I was going to be disappointed with the results, yet I still continuously went to sleep later than I should have. I slept, on average, 7.35 hours. The recommended amount for teens is around 9 hours, so I'm losing a lot of sleep time. Every night my sleep debt grows. It scares me, and I wonder if I'll ever get out of that debt. Because I wake up at 6:45 on school days, I should sleep by 10 at the latest every school night to be ready for the next day. I need to eliminate phone time before bed! It makes it easy to get distracted and keeps me restless. A question I have is about snoring. My friends and family tell me that sometimes I snore and sometimes I don't, and I wonder where that discrepancy comes from.