Answer:
Explanation:
1- the purpose of blood flow-circulatory system- is to convey Oxygenated blood, oxygen bonded with haemoglobin in the RBC with Nutrients - and distributed these through the arteries and capillaries away from the heart, to reach the cells and tissues, and transported the wastes of theses cells and tissues , with C02 through the veins back to the heart and the kidney.
2. During diastole,deoxygented blood from the inferior and superior vena cavae entering the R.atrium, passes through the tricuspid valve into the Right Ventricle. Simultaneously, oxygenated blood returning through the pulmonary veins enters the left Atrium,emptied through the bicuspid valve into the Left.Ventricle.
During systole, the two ventricles contracts. The Right ventricle contracts, the pressure of the blood forces the tricuspid valve to close,and therefore de -oxygenated blood pushes the pulmonary valves to open and blood passes through the pulmonary artery to reach the lungs where exchanges of oxygen with carbon dioxide occurs.The blood is now oxygenated and returns to the left atrium via pulmonary veins.
Simultaneously, the left ventricle contracts,the oxygenated blood it contains forced the bicuspid valve to close so that blood is forced through the aortic valve to empty into the aorta into the systemic circulation,branches of the carotid artery supplies the heart from the aorta.
The Whole cycle continues.
The same receptor that responds to norepinephrine also respond to epinephrine, increasing the action of both. Adrenal medulla is NOT affected by the parasympathetic division of the autonomic nervous system (ANS
Explanation:
Naturalists began to focus on the variability of species; the emergence of paleontology with the concept of extinction further undermined static views of nature. In the early 19th century Jean-Baptiste Lamarck (1744–1829) proposed his theory of the transmutation of species, the first fully formed theory of evolution.
In classical Latin, though, evolution had first denoted the unrolling of a scroll, and by the early 17th century, the English word evolution was often applied to 'the process of unrolling, opening out, or revealing'. It is this aspect of its application which may have been behind Darwin's reluctance to use the term.
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Answer:
Channel proteins and Carrier proteins
Explanation:
These are type of membrane proteins that transcend the entire length of phosphoslipid bi- layer in the plasma membrane.They facilitate the movement of ions and molecules across the walls of the plasma membranes.
Generally, substances like glucose, amino acids, are too large to pass through the phopholipid bilayers. Likewise ions of potassium, sodium calcium, because of their polarities can not pass through either. They are ferried across the phospholipid by group of protein structures called channel proteins. Some are also transported across by carrier proteins. The process by which these protein structures aided the diffusion of substances across the phospholipid bilayer is called Facilitated diffusion.
Channel proteins are pores, that are filled with water molecules with the entrance well gated. That is the entrance is controlled by part in the inner structure of the protein which can open or close the pores like a gate to control the movement of ions across it. e.g Sodium channels are gated for movement of sodium ions by voltage or ligands(chemicals) during nervous transmission to elicits action potential. Like wise Potassium channels allow diffusion of potassium ions across the phospholipid bilayers. it gates are shut when sodium channels are open; this regulate ion exchange.
Their structures are well fixed in shape , specific to the substance or ions being transported;and the rate of diffusion depends on the like hood of opening of the gate or closure.
Carrier molecules also in the membranes do not have a fixed shape, and their transport direction is determined by the direction of concentration gradients. Thus they can flip on either sides of the membranes to aid diffusion across. Their movement can be both passive and active, and the rates of diffusion depends on the number of available carrier proteins in the membrane. They are also specific to the ions they transport.And are not gated,
Therefore these two membrane integral proteins facilitate movements of substances across the phospholipild bilayers
Ancient organism remains, fossil layers, similarities among organisms alive today, similarities in DNA and similarities of embryos.
