Factors Leading to Coronary Heart Disease (CHD)

As of 2010 the leading cause of death is coronary heart disease resulting in over 7 million deaths. Coronary heart disease or short CHD is a heart disease which is caused by gradual build up of fatty material inside the coronary artery which supply's the heart with oxygen as show in picture 1.

Picture 1: Coronary Heart Disease

The arteries get narrowed stopping the red blood cells to reach the heart. This process is is called atherosclerosis and the fatty material is called atheroma. The fatty material that builds up in the arteries is mostly low density lipoprotein (LDL) or bad cholesterol. Lipoprotein is a molecule that carries cholesterol throughout the bloodstream. Cholesterol is a fat that is produce by the liver from the saturated fat in the diet.

There are many factors that lead to coronary heart disease. One of them is obesity. If people are obese they have a greater chance of heart failure because fatty material build up more gradually since they intake more fats in their diet than they need. There is a greater chance of a blood clot and a stroke because there is too much fatty material on artery walls.

Obesity also raises blood pressure which also affects the chance of getting a stroke. Since the heart pumps faster and stronger in order to get enough blood it builds up pressure inside the arteries which can damage them and make them weaker. High blood pressure can also be cause by stress even if you are not obese. Your heart will work faster and the pressure will still raise.

Another factor that causes CHD is smoking. Smoking can damage lining of arteries making it easier for fatty material to build up. Also the carbon-monoxide from cigarettes can decrease the amount of oxygen in the blood which makes the hearth pump stronger raising the blood pressure. Also nicotine increases the level of adrenaline in the body which makes the heart beat faster which also raises blood pressure. Blood is also more likely to clot.

People who have diabetes have a much higher chance of getting CHD than people without it. Diabetes causes high levels of glucose in the body which affects the strength of artery walls and makes them more likely to develop fatty deposits.

High levels of cholesterol can also cause CHD. There are two types of cholesterol. The LDL as mentioned before and HDL. HDL is a high density lipoprotein which is also known as good cholesterol. While LDL builds up on the artery walls HDL is cleaning it. It is due to the structure of the lipoproteins as shown in picture 2. High concentration of triglyceride makes LDL stick to artery walls while HDL structure, which contains more protein is dissolving it. The lower the level of HDL the bigger the chance of getting CHD.

Picture 2: Structures of HDL and LDL

Coronary heart disease is the leading cause of death as of 2010. Research is being done in order to prevent it by the American Heart Assosiation.


Bibliography:

"Prevention of Sudden Deaths from Heart Disease." American Heart Journal5.3 (2010): 386. Web.

"Diabetes and Your Heart." Diabetes. N.p., n.d. Web. 22 Jan. 2016. <https://www.bhf.org.uk/heart-health/risk-factors/diabetes>.

"Smoking." - Heart Health. N.p., n.d. Web. 22 Jan. 2016. <https://www.bhf.org.uk/heart-health/risk-factors/smoking>.

"Coronary Artery Disease - Coronary Heart Disease." Coronary Artery Disease - Coronary Heart Disease. N.p., n.d. Web. 22 Jan. 2016. <http://www.heart.org/HEARTORG/Conditions/More/MyHeartandStrokeNews/Coronary-Artery-Disease---Coronary-Heart-Disease_UCM_436416_Article.jsp#.VqFMCfmrTIU>.

"HDL Cholesterol: "The Good Cholesterol"" WebMD. WebMD, n.d. Web. 22 Jan. 2016. <http://www.webmd.com/cholesterol-management/hdl-cholesterol-the-good-cholesterol>.

"LDL Cholesterol: How It Effects Your Heart Disease Risk." WebMD. WebMD, n.d. Web. 22 Jan. 2016. <http://www.webmd.com/cholesterol-management/ldl-cholesterol-the-bad-cholesterol>.

"Obesity and Heart Disease." Obesity and Heart Disease. N.p., n.d. Web. 22 Jan. 2016. <http://circ.ahajournals.org/content/96/9/3248.full>.

"Coronary Heart Disease - Causes ." Coronary Heart Disease. N.p., n.d. Web. 22 Jan. 2016. <http://www.nhs.uk/Conditions/Coronary-heart-disease/Pages/Causes.aspx>.

"Heart Disease and Stroke Statistics-2015 Update." Heart Disease and Stroke Statistics-2015 Update. N.p., n.d. Web. 22 Jan. 2016. <http://circ.ahajournals.org/content/131/4/e29.full.pdf+html>

Factors that lead to CHD

Aron T.

Biology 11

1/20/2016

Factors That Lead to Coronary Heart Disease

Coronary Heart Disease (CHD) is when blood flow to the heart is temporarily or permanently blocked. This is problematic to the wellbeing of one’s heart, because blood transports the materials (nutrients, minerals, oxygen) that are required for heart muscles (or any muscle) to contract and sustain the life of those cells. Caption #1 shows the muscles in the heart that are affected by CHD. Coronary Heart Disease can be caused by the buildup of plaque (cholesterol) in the arteries which direct blood to the heart, and by the increase in blood pressure.

Caption #1: Shows the muscles that are damaged by CHD	Caption #2: Shows the changes on a fatty acid after hydrogenation.

Plaque building up in the arteries, also called atherosclerosis, is mainly affected by one’s diet, specifically in the ingestion of lipids. The lipids that are likely to cause CHD are: saturated fats, and trans fats. Trans fats are created artificially from hydrogenated vegetable oils, which would usually be unsaturated, which changes the physical properties of the lipids. Caption #2 shows how the hydrogenation of an unsaturated fat results in a saturated fat that has hydrogen atoms added to its structure. The physical changes allow trans fats to become solid at room temperature. Trans fats also increases LDL (low-density lipoprotein) cholesterol in the body, while decreasing the concentration of HDL (high-density lipoprotein). LDL and HDL transport cholesterol through the body, and LDL is considered to be negative since it contributes to plaque (cholesterol) buildup in arteries.

Caption #3: Shows the results of hypertension on blood vessels.

CHD can also be caused if the blood pressure of an individual is too high, which can be caused by the ingestion of salts. High blood pressure causes hypertension, which accounts for the slight damage to blood vessels and can cause blood vessels to narrow. The narrowing of blood vessels may also contribute to plaque (cholesterol) and fat buildup (atherosclerosis) in the arteries. Caption #3 shows how an increase in blood pressure can affect the buildup of plaque (cholesterol) in blood vessels.

Other factors that can help the rate of CHD, which are not diet related, may be seen as: smoking, physical inactivity, and diabetes. Smoking regularly may raise blood pressure (caused by nicotine), damage the lining of one’s blood vessels, and (similar to trans fats) increases LDL while lowering HDL. Physical activity can help reduce the risk of CHD by regulating blood pressure and the levels of lipids in blood cells. Without regular physical activity, these benefits are not being exploited, and a high blood pressure and high lipid concentration may lead to CHD. Diabetes is a risk for CHD because it promotes high glucose levels in blood cells. This is because the hormone insulin, that helps transport glucose to other cells, is not being created or isn’t being used properly. The result could be an abnormal level of sugar in blood cells. These symptoms can lead to CHD, because it also promotes hypertension and abnormal lipid levels in the body.

While scientists have found connections with trans fats, and other lipids, to CHD, there are often many roadblocks in the development of this research. Human volunteers for the experiment would have to undergo certain diets and exercise, which might be hard to sustain over long periods of time (Allott/Mindorff 84). The outcome of the experiments could also be affected by the patient's’ DNA, and finding a group with the same genes would be difficult (Allott/Mindorff 84). While scientists have also tried to experiment on animals, the data collected would not necessarily fit symptoms for humans (Allott/Mindorff 84).

Word Count: 591

Bibliography

"About Heart Disease." Centers for Disease Control and Prevention. Centers for Disease Control and Prevention, 2015. Web. 21 Jan. 2016. <http://www.cdc.gov/heartdisease/about.htm>.

"Cardiovascular Disease Risk Factors." Cardiovascular Disease Risk Factors. Web. 21 Jan. 2016. <http://www.world-heart-federation.org/cardiovascular-health/cardiovascular-disease-risk-factors/>.

"Trans Fats." Trans Fats. American Heart Association. Web. 21 Jan. 2016. <http://www.heart.org/HEARTORG/HealthyLiving/HealthyEating/Nutrition/Trans-Fats_UCM_301120_Article.jsp#.VqDgLPkrLIU>.

"Good vs. Bad Cholesterol." Good vs. Bad Cholesterol. American Heart Association. Web. 21 Jan. 2016. <http://www.heart.org/HEARTORG/Conditions/Cholesterol/AboutCholesterol/Good-vs-Bad-Cholesterol_UCM_305561_Article.jsp#.VqDh8PkrLIU>.

"Basics About Diabetes." Centers for Disease Control and Prevention. Centers for Disease Control and Prevention, 2015. Web. 21 Jan. 2016. <http://www.cdc.gov/diabetes/basics/diabetes.html>.

Allott, Andrew, and David Mindorff. IB Biology. 2014 ed. Oxford UP. Print.

Coronary Heart Disease

Fatty Acids, Good or Bad? 

by Celine Ernest

Figure 1- Shows the different stages from being anorexic to obese and vise versa.

It is important for us humans to stay well nourished, in other words, keeping a healthy diet. Staying well nourished depends on the foods and drinks a person consumes daily. Fats can however affect peoples lives, while on the other hand people can lack levels of fats that affect their lives as well. For example, there are mental and physical circumstances connected to eating. A person can discover a psychological condition that involves voluntary starvation, which then leads to a loss of body mass. The condition is called anorexia nervosa, anorexia is the third most common psychological condition amongst teens. Anorexia has affected the majority of the population as it is the most common cause of death. The opposite of Anorexia is Obesity, when a person is obese they tend to intake more goods (usually considered to be unhealthy containing unhealthy fats), without any additional exercises. Obesity can lead to coronary heat disease and type two diabetes, CHD reduces life expectancy, as well as increasing health costs. "More than 35% of U.S adults are obese.". Both conditions are caused by either the lack of fats or the excessive intake of fats as shown in Figure 1. 

Figure 2- Displays the Saturated fatty acid and the Unsaturated
Fatty Acid. As shown above Saturated fatty acids contain single
bonds whereas Unsaturated fatty acids one or more double bonds.

 Fatty acids are part of the carboxyl group (-COOH). A long hydrocarbon chain made up of a chain of carbon atoms with hydrogen atoms liked by single covalent bonds. The chain can be up to 14-20 atoms long. The chain is either saturated or unsaturated. Saturated fatty acids contain single bonds between all carbon atoms, therefore containing a lot of extra hydrogen. Unsaturated fatty acids is when the molecule contains one or more double bonds. However trans fats or trans-unsaturated fatty acids are uncommon to find but are produced artificially by hydrogenation of vegetable or fish oils. According to Harvard T.H. Chan, trans fat raise LDL cholesterol levels and lower HDL cholesterol levels. Which means that once a person overly abuses trans fats, it will increase risks of developing heart diseases such as coronary heart disease. 

Figure 3- Shows the difference between a normal
artery with a healthy blood flow, versus an artery
showing fatty plaque.

Coronary heart disease can be a side affect of obesity. Coronary heat disease, is when your coronary arteries become narrowed down by fatty material (atheroma) within their walls. The arteries affected are those that supply the heart with oxygen and rich blood. Over many years the build up of plaque occurs in the artery, which is called atherosclerosis. However, correlation has been found that saturated fatty acid does not affect rates of CHD. In the text book, they mention the Maasai of Kenya whom have a diet that is rich in meat, fat, blood and milk. Maasai do however stay active and work, and are in need of those fats in order to give them minerals, vitamins, and energy. And Maasai's do not have enough food to eat for Breakfast, Lunch and Dinner, meaning that the next meal can be in over a day or two. This additional information does show that their comparison is too specific and should be generalized to people who consume too many of the fats such as saturated fatty acids, cis- monounsaturated fatty acids, trans fat, etc. It all concludes to the importance of staying nourished, keeping active, having a healthy social life as stress can cause heart diseases too (chronic stress). Too much of a substance will always remain to be unhealthy as our body is in need of a balanced diet. 

Bibliography:

"How Many People Are Affected By/at Risk for Obesity & Overweight?" NIH, n.d. Web.

Allott, Andrew. Biology for the IB Diploma: Standard and Higher Level. Oxford: Oxford UP, 2011. Print.

"Anorexia Facts and Statistics - Futures." Futures of Palm Beach. N.p., n.d. Web. 20 Jan. 2016.

"The Truth about Fats: The Good, the Bad, and the In-between." Harvard Health Publications, 3 Feb. 2015. Web. 20 Jan. 2016.

Elena: Factors Leading to Coronary Heart Disease (CHD)

Coronary Heard Disease is a condition which defines the blockage of arteries that supply blood to the heart. Our heart is a muscle and cannot function without oxygen. The blood flowing through the arteries contains oxygen, therefore the blockage of these arteries leads to the dysfunction of our heart muscle. As visible in figure 1, an artery of an individual with the condition of CHD has a lower rate of blood supply due to the clotting within the artery, while an individual that does not suffer such disease provides the heart with maximum supply of blood.

Figure 1: comparison beween a healthy and clotted artery.

Figure 2: Human heart diagram with labelled coronary arteries

 In figure 2, we can see that there are two main coronary arteries in the human heart, the left and the right, which separate into many smaller arteries in order to distribute the oxygen-filled blood throughout the entire heart.

However, once there is blockage in one artery, that doesn't cut down the circulation of blood throughout the entire heart, but only that particular part of the heart. This partial blockage leads to severe chest pain, which spreads towards the shoulders, arms, neck, upper back, the general area around the chest. This pain is also known as angina. However, if there is blockage in both main arteries, a heart attack occurs, which if strong enough may lead to death.

There are many ways that an unhealthy lifestyle leads to heart disease, such as smoking, diabetes, or obesity. A person's diet with high doses of cholesterol or fat causes plaque, also known as patches formed that cause clotting, to form on the inside of arteries, taking up space, therefore preventing blood flow. This condition is also known as atherosclerosis. On the other hand, CHD isn't only caused through and unhealthy living, sometimes there are genetic factors that determine the situation, and also aging. When we age, it is very possible that our artery walls form a more fixed, less elastic shape and become less flexible, limiting the efficiency of blood flow.

The usual symptom of CHD is angina, as mentioned above. However, there is a way of testing your heart activity in order to draw a reliable conclusion. One of the least painful and reliable ways to test your cardiovascular health is through an electrocardiogram or EKG test. Stress testing is also another way to test your health. Whether the stress testing shows abnormality in one's blood pressure or heart rate, length of breaths taken or condition of the chest pain, it is likely one is diagnosed with CHD. Other ways doctors test this disease is through blood samples and X rays as well.

Figure 3: ways to treat coronary heart disease (medications,
angioplasty, and surgery).

The positive aspect is that there are medications and ways to improve your daily life and treat this condition. The main way to not only treat, but also avoid CHD is by making healthy diet and life choices, which include avoiding smoking, forming a low fat, salt and sugar diet, and exercise. On the other hand, if one;s condition is much more severe and cannot be cured with only changing their lifestyle, medications will be suggested by a doctor which will raise the level of oxygen within an individual's blood stream and cause their heart to work more efficiently. Lastly, another way that severe heart conditions are cured is through surgery, all including the increase of blood supply to one's body. Figure 3 provides a visual representation of three effective ways to treat this disease. As already mentioned, medication and surgery, but also angioplasty which has multiple methods to insert tools inside the artery and separate the plaque into small fragments that are later washed away by the blood.


Works Cited:

"How is coronary heart disease diagnosed?" National Heart, Lung, and Blood Institute. N.p., n.d.Web. 21 Jan. 2016. <http://www.nhlbi.nih.gov/health/health-topics/topics/cad/diagnosis>.

"Coronary Heart Disease." British Heart Foundation. N.p., n.d. Web. 21 Jan. 2016.<https://www.bhf.org.uk/heart-health/conditions/coronary-heart-disease>. 

"Heart Disease Health Center." WebMD. N.p., n.d. Web. 21 Jan. 2016. <http://www.webmd.com/heart-disease/guide/heart-disease-coronary-artery-disease>. 

"Cholesterol Health." BergaMet. N.p., n.d. Web. 21 Jan. 2016. <http://bergamet.co.uk/cholesterol-health>. 

"Treatment of Coronary Artery Disease." Heart Point. N.p., n.d. Web. 21 Jan. 2016.<http://www.heartpoint.com/treatcoronaryartdis.html>. 

Mitosis Ana Djurica

Mitosis is cell division in the cell cycle, that ends with producing two identical cells-daughter cells. The 1st stage of cell division is interphase. Interphase is the phase of the cell cycle in which a typical cell spends most of it's life, the 'daily living' or metabolic phase of the cell, in which the cell obtains nutrients and metabolizes them, grows, reads it's DNA, and conducts other "normal" cell functions... It is divided into 3 phases; G1(gap phase 1), S(synthesis) and G2(gap phase 2). 

The ilustration of interphase

• G1-cell grows larger

• S-genome is replicated

• G2-separates the newly replicated genome and marks the end of interphase.

The cell cycle

Mitosis-events that occur in 4 phases of it:

1. Prophase-the spindle microtubules grow and extend from each pole to the equator, chromosomes super coil and become short and bulky and the nuclear envelope breaks down.
2. Metaphase-the chromatids move to the equator and the spindle microtubules from each pole attach to each centromere on opposite sides.
3. Anaphase-the spindle microtubules pull the sister chromatids apart splitting the centromeres. This splits the sister chromatids into chromosomes. Each identical chromosome is pulled to opposite poles.
4. Telophase-the spindle microtubules break down and the chromosomes uncoil and so are no longer individually visible. Also the nuclear membrane reforms. The cell then divides by cytokinesis to form two daughter cells with identical genetic nuclei.

Interphase+4 phases of mitosis

Sources:

•  http://ibguides.com/biology/notes/cell-division
• https://en.wikipedia.org/wiki/Interphase

MITOSIS

Mitosis is the  a process of cell division in which two new nuclei are formed, each containing the original number of chromosomes. The two newly formed nuclei are known as identical daughter cells. When mitosis occurs the chromosomes from one nucleus split into two matching sets which inhabit each daughter cell. The duplication and split of the chromosomes occurs in order for the twin daughter cells to be able to obtain information for future functions.

Figure 1:
The S stage

In order for this process to occur, each cell must undergo a repeating set of events, which occur in the beginning stages of the cell cycle also known as the interphase. The replication of genetically identical nuclei is reached through the four phases of mitosis; prophase, metaphase, anaphase and telophase. The first stage, the interphase can be further broken down into 3 stages/phases. The G1 stage, the S stage and the G2 stage. However the duplication of the DNA only occurs in the S stage. During the S phase, the DNA replicates resulting in the production of 2 copies of each chromosome, as shown in Figure 1. The cell then moves onto phase G2, where it continues to prepare for mitosis and cell division.

Mitosis, as mentioned above is a process composed of 4 stages, the first stage being prophase. During prophase the chromosomes, begin to condense or in other words thicken. The twin copies of each chromosome are called the sister chromatids. The nuclear membrane which surrounds and protects the cell nucleus disintegrates (breaks apart into pieces), the nucleolus then disappears, and the centrosomes move towards opposite poles of the cell. During the movement of the centrosomes the spindle fibers, which grow out of the centrioles, form and move to opposite poles of the cells as well. Metaphase is the second stage of mitosis. During this stage the duplicated chromosomes line up in the center of the cell. The spindle fibers are now fully grown and formed allowing them to attach itself to each sister chromatids. The third phase, anaphase occurs when the sister chromatids of each chromosome begin to divide. The centromeres which have moved to opposite poles of the cell, and hold the sister chromatids together, split resulting in the chromosomes moving away from each other along the attached spindle fibers. The last phase, telophase is the phase in which the two groups of chromosomes reach opposite ends of the cell. The nuclear membrane as well as the nucleus begin to form around each group while the spindle fibers detach themselves from the chromosomes.

Post the process of mitosis, the last and final stage of the cycle occurs. This stage is called the cytokinesis and it is the stage in which the cell along with the cytoplasm split and divide into two identical daughter cells. Each daughter cell is made up of its nucleus which is a replica of the genetic material from the ‘’parent cell’’.

Figure 2
Visual representation of the stages of mitosis 

Mitosis KKesic

How does mitosis produce two genetically identical nuclei?


Mitosis is a type of cell division that in the end produces two daughter cells, with each having the same kind and same number of chromosomes as the parent nucleus.
 Two daughter cells -  occurs when a cell undergoes the cell cycle. The cell cycle has a couple of phases.The first being the interphase; which, as well,  has a couple of stages. The first stage is when the cell grows and matures. The second is when the DNA is copied. The third is when the cell is prepared for division, at this phase the two daughter cells still are not format because their process starts in the mitosis phase but in that phase they are still not developed but the nucleus divides into 2 identical nuclei and from that point in the next phase the two daughter cells are formed.. Mitosis is where the devision of diploid eukaryotic nucleus. The development of the two daughter cells is completed in the cytokinesis phase where the division of the cytoplasm occurs to from two daughter cells.

Figure 1: Cell cycle - from mitosis to two daughter cells which each contain the exact copies of the parent cell's chromosomes.
(Google Images) 

Mitosis is divided intro four stages:

• Prophase - the spindle microtubules grow and extend from each other to the equator from each pole. As they become short an bulky the nuclear envelope breaks down.
• Metaphase - chromatids move to the equator and the spindle microtubules from each pole attach to each centromere on opposite sides.
• Anaphase - the spindle microtubules pull the sister chromatids apart ,which splits the centromeres. This splits the sister chromatids into identical chromosomes. As they are then pulled to opposite poles.
• Telophase - the spindle microtubules break down. The chromosomes unhelix and they are not individually visible. The nuclear membrane reforms. Then, the cell divides to from two daughter cells with identical genetic nuclei. 

During the prophase, the chromosomes become more visible under a light microscope as they superhelix and become shorter and more ponderous. Then, the nuclear envelope fractures. Afterwards, the spindle microtubules grow and extend from each pole to the equator. So, at the metaphase the chromatids move to the equator. The sister chromatids are are two DNA molecules, that are formed by DNA replication; that is also how they are identical. In the anaphase, these sister chromatids are separated. While the spindle microtubules attaches to centromere and pulls the chromatids to opposite poles. The chromosome then occurs - while the sister chromatids are separated they are called chromosomes. Which would mean that each pole has the same chromosomes ( it is the same genetic material). The final step is when the microtubules break down. While the chromosomes unhelix and the nuclear membrane reforms. Then the cell divides into two daughter cells with each having genetically identical nuclei.

Figure 2: How a chromosome looks when duplicated
(Google images)

In further detail, during the DNA replication each chromosome produces an identical of itself; but at this point they are called chromatids and they are attached at the centromere. Then, the chromatids separate at mitosis and from the two identical daughter nuclei.

Figure3: Two daughter cells - showing how they are exactly the same and have the identical nuclei.
(Google images)

Resources:

"IB Biology HL Exam Study." - LiveBinder. N.p., n.d. Web. 11 Nov. 2015.

"The Cell Cycle, Mitosis and Meiosis." — University of Leicester. N.p., n.d. Web. 11 Nov. 2015.

Allott, Andrew, and David Mindorff. IB Biology. Oxford: Oxford UP, 2014. Print. IB Diploma Program - Biology Course Companion.

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