Answer: True
Explanation:
<u>A cell membrane consists of a lipid bilayer made of polar phosphate head and a nonpolar lipid tail.</u> It is semipermeable and regulates the transport of materials through it. For this,<u> it is selectively permeable</u> and since it is made of lipids, hydrophobic and small polar molecules can diffuse easily through it by simple diffusion and down their concentration gradient. However, polar molecules, large molecules (such as glucose) and ions are not able to pass through it because they are repelled.
To accomplish the transport of these molecules that can not diffuse, proteins embebbed in the membrane function as carriers that enable the transport of polar molecules, large molecules and ions by passive (through facilitated diffusion, down its concentration gradient) or active transport (movement against its concentration gradient).
<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.
I believe the answer is b
Answer:
I think C
Explanation:
New neurons are born not from mature nerve cells but rather develop from neural stem cells that remain in our brains throughout life. Indeed, in some brain areas, there is continual turnover of neurons - old ones die and new ones are born - and these new neurons can participate in circuits that underlie learning.
Answer:
The electron transport chain is a cluster of proteins that transfer electrons through a membrane to create a gradient of protons that creates ATP (adenosine triphosphate) or energy that is needed in metabolic processes for cellular function.
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