Answer:
Cell organelles are small structures that exist within cells and perform specialized functions
Based upon the presence and absence of membrane cell organelles can be classified into three types:
- Membrane less: Cell organelle that lack membrane for example ribosomes they are not bounded by any membrane.
- Single membraned: Cell organelle that are bounded by single membrane but they are only found in Eukaryotic cell. For example lysosome, Endoplasmic reticulum, lysosome, vacuole.
- Double membraned: Cell organelle that are bounded by double membrane. Example chloroplast and mitochondria, they are only present in eukaryotic cell.
Answer:
Cell differentiation is the process by which dividing cells change their function. DNA is essential in gene expression, which gives the ability of cells that are specializing to be able to adequately perform the role they are trying to carry out. It is generally understand that all the cells in our body contain the same DNA, yet they carry out different functions. The key is understanding that specific parts/combinations of the genome are activated which changes the function and shape of the cell. Additionally, if the DNA is damaged or mutated in certain areas of the chromosome, it can cause certain differentiated cells to not function properly.
Explanation:
<u>The heart is a cone-shaped muscular organ located within the mediastinum of the thorax.</u>
The mediastinum is the space lined with membranous tissue between the lungs. The mediastinum contains not only the heart but also the great vessels (pulmonary artery, aorta, pulmonary veins, and the superior and inferior vena cava), as well as parts of the esophagus and the trachea.
<span><u>Its apex rests on the </u><u>diaphragm</u><u> and its superior margin lies at the level of the </u><u>2nd</u><u> rib.</u>
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The apex of the heart is the conical area created by the confluence of the ventricles, but mainly by the left ventricle. It rests on the diaphragm. The superior margin of the heart, also known as the base, lies at the level of the second rib.
<span><u>Approximately two-thirds of the heart mass is seen to the left of the </u><u>midsternal border</u><span><u>.</u>
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This is because to the left of the midsternal border lies the left ventricle which comprises most of the heart mass as the left ventricle is the one responsible for pumping blood throughout the systemic circulation and significant pressure should be overcame; resulting to the physiologic hypertrophy of the left ventricle.
</span><span><u>The heart is enclosed in a serosal sac called the </u><u>pericardium</u><u>. The loosely fitting double outer layer consists of the outermost fibrous pericardium, lined by the parietal layer of the serous pericardium.</u></span>
The pericardium is one of three layers of the heart (other ones being the myocardium and the endocardium); and is the outer layer of the heart. The pericardium is composed of two tissues, the fibrous pericardium and the serous pericardium. The pericardium functions to lubricate the movement of the heart by the action of the pericardial fluid.
<span><u>The heart has </u><u>four</u><u> chambers. R</u></span><span><u>elative to the roles of these chambers, the </u><u>atria </u><u>are the receiving chambers, </u></span><span><u>whereas the </u><u>ventricles </u><u>are the discharging chambers.</u>
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The four chambers of the heart are namely the right atrium, right ventricle, left atrium, and the left ventricle. Venous blood goes to the right atrium via the vena cavas then to the right ventricle via the tricuspid valve; then to the pulmonary circulation via the pulmonary artery where it will be oxygenated. From the pulmonary circulation, the left atrium will receive the oxygenated blood via the pulmonary veins then to the left ventricle via the mitral valve where it will be pumped to the systemic circulation via the aorta.
1: False. Chemical.
2: False. Endocrine.
<span>This allows the muscles to become active and use the glucose as a way of creating energy to be able to perform the exercise. The more the glucose is being used instead of stored, the more likely it will be that the person will be able to lower their overall levels and keep them in check.</span>