PLTW Heart Disease

How do LDL and HDL differ structurally and functionally?

Functionally - LDL takes the cholesterol to the cells, while HDL removes excess cholesterol from the bloodstream and takes it back to the liver Structurally - a general structure includes a core, which contains cholesterol esters and a surface monolayer of phospholipid, unesterified cholesterol and specific proteins; the difference is LDL has high density due to high protein/lipid ratio (50% cholesterol, 25% protein), and HDL is the highest in cholesterol esters and is made of 20% cholesterol and 50% protein

Given Anna's medical history, describe the most likely reason she needed a pacemaker.

With high blood pressure, sickle cell anemia, diabetes, she most likely needed a pacemaker because of all the work taking toil on her heart.

Describe how the structure of the aorta relates to its function in the heart.

The aorta is a tube that transports the oxidized blood to the rest of the body. It needs to be bigger because it must push all the blood through the rest of the body.

Cardiology

The study of the heart and its action and diseases.

Diastolic Pressure

Blood pressure that remains between heart contractions.

How are the concentrations of LDL and HDL associated with the risk for heart disease and associated disorders?

A high concentration of HDL can lower the risk for heart disease and associated disorders A high concentration of LDL shows risks for heart disease and associated disorders; LDL can build up in the arteries (can result in atheroscerlosis) and lead to the hardening of arteries and lead to heart diseases

What do the results of a cholesterol test mean? How do patients interpret each value?

The results of the cholesterol test show whether your cholesterol levels are healthy. Patients can interpret each value based upon scales for each molecule. For total cholesterol, less than 200 mg/dL is considered healthy, while 200 - 239 mg/dL is borderline high and 240 mg/dL is high. For HDL, less than 40 mg/dL is low for men and less than 50 mg/dL is low for women, and 60 mg/dL is considered healthy. For LDL, less than 100 mg/dL is optimal, 100 - 129 mg/dL is near or above optimal, 130 - 159 mg/dL borderline high, 160 - 189 mg/dL is high, and 190 mg/dL is very high. For triglycerides, less than 100 mg/dL is optimal, less than 150 mg/dL is normal, 150 - 199 mg/dL is borderline high, 200 - 499 mg/dL is high, and 500 mg/dL and above is very high. These are the ranges to interpret the cholesterol test, but other factors such as age, can affect the ranges, and your doctor can take these factors into account, and adjust the results.

How does intake of unsaturated, saturated, and trans fats affect cholesterol levels and overall health?

Unsaturated - help reduce LDL, and lower risk of heart disease and stroke; provide nutrients to help develop and maintain cells Saturated - raises the level of cholesterol in blood; high levels can increase the risk of heart disease and stroke Trans - partially hydrogenated, raises LDL, which can clog arteries and cause heart disease, and lower HDL

Valve

A body structure that temporarily closes a passage or orifice, or permits movement of fluid in only one direction

Heart Rate

A measure of cardiac activity usually expressed as the number of beats per minute.

Electrocardiogram (EKG)

A measurement of heart electrical activity.

Sinoatrial Node

A small mass of tissue that is made up of Purkinje fibers, ganglion cells, and nerve fibers, that is embedded in the musculature of the right atrium, and that originates the impulses stimulating the heartbeat -- called also S-A node, sinus node.

Atrioventricular Node

A specialized mass of conducting cells located at the atrioventricular junction in the heart.

Mitral Valve

A valve in the heart that guards the opening between the left atrium and the left ventricle; prevents the blood in the ventricle from returning to the atrium. Alternative name is bicuspid valve.

Tricuspid Valve

A valve that is situated at the opening of the right atrium of the heart into the right ventricle and that resembles the mitral valve in structure but consists of three triangular membranous flaps.

Inferior Vena Cava

A vein that is the largest vein in the human body and returns blood to the right atrium of the heart from bodily parts below the diaphragm.

Superior Vena Cava

A vein that is the second largest vein in the human body and returns blood to the right atrium of the heart from the upper half of the body.

Vein

A vessel that returns blood to the heart

Hypertension

An abnormally high blood pressure

Atrium

An anatomical cavity or passage; especially a chamber of the heart that receives blood from the veins and forces it into a ventricle or ventricles.

Pacemaker

An electrical device for stimulating or steadying the heartbeat or reestablishing the rhythm of an arrested heart.

Sphygmomanometer

An instrument for measuring blood pressure and especially arterial blood pressure.

Tissue

An integrated group of cells with a common function, structure, or both.

Artery

Any of the tubular branching muscular and elastic-walled vessels that carry blood from the heart through the body.

What structural differences did you notice between arteries and veins? Relate these differences to the function of the vessels.

Arteries and arterioles have thicker walls than veins, respectively. The increased amount of smooth muscle that is found in arteries gives them extra strength and elasticity to deal with the surges of blood from the heart. Veins have valves within them to prevent backflow of blood. Veins have wider inner diameters, too, that means that they can hold more blood. Since it would be impossible anyway to get all the blood back to the heart as quickly as it left the heart, the veins have to have more blood in them than the arteries.

Explain how cholesterol plays an important role in at least two different human body systems.

Cholesterol plays an important role in the endocrine system and the digestive system. Cholesterol is used in the synthesis of bile acids, which break down food in the digestive system. Cholesterol is also the precursor of pregnenolone, the precursor of all steroid hormones. So without cholesterol, the steroid hormones would not be made

Explain how cholesterol levels could be linked to health events such as strokes and heart attacks.

Cholesterol levels could be linked due to the concentration of HDL and LDL. With high levels of LDL, the arteries can begin to clog, leading to heart disease, strokes, and heart attacks. With high levels of HDL, the HDL can remove excess cholesterol from the bloodstream, and lower the risk of such health events

List five factors or behaviors that affect cholesterol levels in the body, how these factors affect cholesterol levels, and whether the effect is positive or negative with regards to a person's health.

Diet, Stress, Smoking, Physical Activity, and Weight management can all affect cholesterol levels. Diet can either be positive or negative depending on what the person is eating. If the diet is low in trans and saturated fats then the effects will be positive, and if the diet is high in trans and saturated fats then the effects are negative because it increases the "bad cholesterol" LDL. Lots of stress can be negative on a person's health, and have many effects. Long periods of stress can cause an increase in heart rate and blood pressure, which can damage artery walls. Smoking is very negative on a person's health, not only does it damage the lungs, but leads to a higher risk of developing chronic disorders such as buildup in the arteries, which can lead to heart disease. Physical Activity can be positive to a person's health, while it boosts mental wellness, it also decreases the risk of cancer, heart disease, and blood pressure. Physical activity can also raise levels of HDL, which is good for the body. Finally weight management, if the person is obese, that alone is a major risk factor for heart disease¸ and with the diet eaten to get to such a weight, involves high amounts of LDL.

Atherosclerosis

Hardening of the arteries is a common disorder. It occurs when fat, cholesterol, and other substances build up in the walls of arteries and form hard structures called plaques.

What do you think would happen in the heart if the AV node could no longer do its job? Explain how this would affect the contraction of the heart and the movement of blood.

If the AV node could no longer do its job, then the ventricles would not have the electrical charge needed to contract, and the blood would not be able to move through the rest of the body.

Now that you have seen a heart up close, explain how the actual structure differs from your heart box study tool.

In the actual structure, the arteries and veins are different sizes. The ventricles and atria are different sizes and thicknesses to comply to the needs of the right and left parts of the heart.

3. In most of the body, the arteries carry oxygenated blood and the veins carry deoxygenated blood. The exception to this pattern is the heart. Explain how and why specific arteries and veins of the heart are different from the pattern seen in the rest of the body.

In the exception of the heart, pulmonary veins transport oxygenated blood from the lungs to the heart. This is different from the rest of the body because the veins are supposed to carry deoxygenated blood.

Why do you think it is important to take an average resting heart rate versus relying on one value

It is important to take an average heart rate because external factors can impact the heart rate such as previous positions, temperature, previous physical activity, etc. This average allows for a reliable heart rate.

At the time of her cardiac work-up, Anna Garcia had an average resting heart rate of 98bpm. What does this say about her overall heart health?

It says overall that her heart is not at a healthy rate. It means that it requires more from the heart to pump blood to the rest of her body. This may overwork the heart, and cause other health problems. Overall, her heart health is lacking and may become worse.

Explain how an ACE inhibitor might have helped Anna mediate her blood pressure.

It works by blocking the body from producing a chemical called angiotensin II. Angiotensin II enters the blood stream, and makes your blood vessels become narrower, which gives your blood less room to move (raises blood pressure). The ACE inhibitor stops this chemical, and in turn relaxing the blood vessels and lowers blood pressure.

What are LDL and HDL?

LDL - low-density lipoprotein (transports cholesterol to and from the cells), takes cholesterol to the cells from the liver; high levels can lead to buildup in the arteries and result in heart disease HDL - high-density lipoprotein, removes excess cholesterol from the bloodstream and takes it back to the liver; can reduce risk of heart disease and stroke

Blood Pressure

Pressure exerted by the blood upon the walls of the blood vessels, especially arteries, usually measured by means of a sphygmomanometer and expressed in millimeters of mercury.

What can patients do to change the levels of LDL and HDL in their blood?

Patients can change the levels of LDL and HDL by changing their diet (lowering the saturated fat), increase in physical activity, losing weight, lowering stress, and medication

Propose reasons why the heart rates of different people are different when exposed to the same stressor or to the same physical activity, even though their resting heart rates are the same

People's heart rate may be different due to the way the brain may react to the stressor or physical activity. It may also be different due to the physical health of the individual, and rather they are healthy or not. These factors may all cause differences even if it is the same stressor.

What is prehypertension? Why do you think it is valuable to know if you are considered prehypertensive?

Prehypertension is a case before stage one of high blood pressure. It is valuable to know so that you can make proper changes to your lifestyle in order to keep your blood pressure at a healthy level.

Aortic Valve

The semilunar valve separating the aorta from the left ventricle that prevents blood from flowing back into the left ventricle.

Cell

The smallest structural unit of living matter capable of functioning independently.

In the space below, explain what an EKG can tell a physician about the heart of a specific patient.

The EKG can tell irregular heartbeat, irregular speed of contractions, angina (chest pain that can indicate tissue damage), or even tissue death (myocardial infarction, also known as a heart attack).

Systemic Circulation

The branch of the circulatory system that supplies all body organs and then returns oxygen-poor blood to the right atrium via the veins.

Anna's autopsy revealed that she had an external pacemaker. What does the pacemaker replace in the heart? Explain.

The electrical charge which is what makes the heart contract and pushes the blood through the body. The pacemaker is needed for regular beats and putting the blood through the whole paper. SA node

Using what you have learned about the structure and function of the heart, explain why left ventricular hypertrophy can be fatal if left untreated.

The enlarged muscle loses elasticity and stiffens, preventing the chamber from filling properly and leading to increased pressure in the heart. The enlarged muscle tissue compresses its own blood vessels (coronary arteries) and may restrict its own supply of blood. The overworked muscle weakens.

Aorta

The large arterial trunk that carries blood from the heart to be distributed by branch arteries through the body.

What are two differences you see when comparing the four chambers of the heart? Relate these differences to the function of each chamber.

The left chambers are larger than the right chambers. The right atrium and ventricle function is for transporting deoxidized blood, while the left atrium and ventricle functions for transporting oxidized blood.

Which chamber of the heart do you think is the most muscular? Explain your reasoning.

The left ventricle because it is in charge pumping blood through the aorta. This job is what gives the rest of the blood to the body, so it needs the most muscle to pump the blood through the rest of the body.

Systole

The stage of the heart cycle in which the heart muscle contracts and the chambers pump blood.

Diastole

The stage of the heart cycle in which the heart muscle is relaxed, allowing the chambers to fill with blood.

Pulmonary Circulation

The passage of venous blood from the right atrium of the heart through the right ventricle and pulmonary arteries to the lungs where it is oxygenated and its return via the pulmonary veins to enter the left atrium and participate in systemic circulation.

Systolic Pressure

The pressure generated by the left ventricle during systole

What do you feel are the pros and cons of using cholesterol-lowering drugs to treat high cholesterol?

The pros of using cholesterol-lowering drugs is it lowers the risk of heart disease and other associated diseases, while also mildly affecting and raising HDL and triglyceride count. While these may be positive things, there are many side effects for these drugs. They may be mild side effects or even rare afflictions, but they are still there, such as damage to the liver and muscle problems. In the end the pros outweigh the cons due to the small damage and rareness of side effects of the medication.

Pulse

The rhythmic expansion and recoil of arteries resulting from heart contraction; can be felt from the outside of the body

What did you need to keep constant in your experiments? Why was it important to keep these factors constant?

The same person, the same amount of time between readings and for the readings, the same number that is pumped to in the beginning, and the same temperature. These factors must remain constant because if not other factors that are not the independent variables could change the data, and the data would be corrupted.

Cardiovascular System

The transport system of the body responsible for carrying oxygen and nutrients to the body and carrying away carbon dioxide and other wastes; composed of the heart, blood vessels, and blood.

Anna's autopsy report noted mitral valve prolapse. This means that the mitral valve does not close properly. Explain why this could be a problem.

The valves are supposed to help the blood move in the right direction. If the valves do not work properly then the blood will not move in the right direction, and the body will not get the oxidized blood it needs.

2. A growing fetus has a vessel, the ductus arteriosus, in the heart that connects the pulmonary artery with the aorta and conducts blood directly from the right ventricle to the aorta. Why do you think this vessel closes soon after birth?

The vessel closes to have full separation between oxygenated blood and deoxygenated blood. The right atrium and ventricle are supposed to transport the deoxygenated blood, and the left atrium and ventricle are supposed to transport the oxygenated blood and then transfer to the aorta, where the blood will go to the rest of the body.

Explain what happens to tissues, such as the heart, or the brain, if oxygenated blood is not delivered in a timely manner.

Tissue starts to die if oxygenated blood is not delivered. If the tissue dies, then the organs will fail. If the organs fail then the body will not be able to operate and die. This is especially in the brain, brain tissues rely on oxygen, and without, significant brain damage can occur.

Why do doctors monitor the concentrations of LDL and HDL in patients' blood?

To evaluate the risk of heart disease and other associated disorders, 40 - 60 mg/dL for HDL, and less than 129 mg/dL for LDL

What other molecules in a patient's blood are monitored along with LDL and HDL?

Triglycerides, blood sugar level, total cholesterol

Describe the mechanisms in place to prevent the blood from flowing in the wrong direction through the heart.

Valves prevent the blood from flowing in the wrong direction. There are valves on the connecting arteries, and keep the blood moving in the right direction.

What are two causes of blood pressure changes that might occur in a person within a given day?

a. Eating. The flux of nutrients such as sodium, could change the blood pressure. These changes may be minor, but the food we eat affects our body and how it acts. b. Position. Different positions require different requirements from your body, so if you are lying down versus standing up, it might take more energy standing up. When you are relaxed lying down, then blood pressure will be lower due to the relaxation.

Did you get the same blood pressure reading manually as you did with the use of probes? Provide at least two reasons these values may be different.

a. No. i. Firstly, the probe could be more accurate than the manual reading. This could be to human error or just the fact of technology. ii. Secondly, other factors in between measuring the two readings could affect the reading. Temperature change, eating, position could all affect the readings.

What are some factors that can increase or decrease the heart rate and the beat you feel at each pulse point?

• Raise - stimulants, emotions, drugs, activity • Lower - position, drugs (depressants), alcohol