Clanges typical of higher levels of activity D. a lower systolic blood pressure
ID: 272702 • Letter: C
Question
Clanges typical of higher levels of activity D. a lower systolic blood pressure E. a similar cardiac output. 27. The main difference between the pulmonary circuit and the systemic circuit is that the pulmonary circuit A. has lower pressures. D. has a lower flow volume per time E. has a lower cardiac output. B. is arranged in parallel. C. has a higher overall resistance. The principal function of the arterioles is to: A. allow white blood cells to leave the D. control the amount of blood flow to the circulation. tissue. E. hold the largest blood volume in the B. act as pressure reservoir. C. carry blood away from the capillaries. O. What is the best explanation for the prolonged duration of the cardiac action potential A. Voltage-gated Na" channel B. Voltage-gated Ca2 channels remain open C. Voltage-gated K' channels delay opening D. Both b and c E. all of the above s remain open The neuron converts an electrical signal to a chemical signal in the A. Dendrite B. Presynaptic terminal C. Axon D. Cell body E. Axon hillock dR. Which oxygen storage compartment tends to be the smallest in diving mammals? E. Hemoglobin A. Blood B. Lungs C. Myoglobin D. Interstitial fluidsExplanation / Answer
27] Option [a] has a lower pressure
Pulmonary circuit includes the flow of deoxygenated blood from the right ventricle to the lungs through the pulmonary arteries. In the lungs, exchange of CO2 and O2 takes place and the oxygenated blood is brought back to the left atrium by the pulmonary veins.
Systemic circulation includes all the blood vessels that take the oxygenated blood to every part of the body from the left ventricle. The left ventricle has to pump blood with great pressure so that the pure blood reaches every body tissue.
This is why left ventricle has thicker myocardial walls than the right ventricle. The blood flows at a higher pressure in the systemic blood vessels as compared to the pulmonary blood vessels.
a] Option--[b] act as a pressure reservoir
The arteries branch off into thinner blood vessels called arterioles. Arterioles furher branch to form the extremely thin capillaries. White blood cells and plasma ooze out of the walls of the capillaries due to the high pressure of blood through these vessels. This plasma and the white blood cells are then collected by the lymph vessels and brought back to the blood in the subclavian artery.
Arterioles have smooth muscle walls and are the primary sites of vascular resistance.The greatest change in blood pressure and velocity of blood flow occurs at the transition of arterioles to capillaries.
b] Option [d] both b and c
The inactivation of the Na+ channels reduce movement of these ions into the cell. At the same time K+ channels open and close quickly allowing for a brief flow of K+ ions out of the cell , making the membrane potential slightly more negative. Ca++ ions move into the cell which in turn opens more calcium channels . This is responsible for the contraction of the heart.
c] Option [ b] presynaptic terminal
The electric signal is translated into a chemical signal at the point of synaptic junction between two neurons. The chemical is a neurotransmitter which is then 'picked up' by the dendrites of the next neuron.
d] Option [ d] interstitial fluids
Myoglobin is the main oxygen storage compartment in diving mammals. Although lungs and blood are also considered as oxygen storage compartments for diving mammals but various research has shown that myoglobin concentration shows a steep rise in all diving mammals during a dive. This trait is more characteristic of deep sea divers than any changes in blood volume, hemoglobin concentration or respiratory volumes.
Interstitial fluids store very little volume of oxygen, if at all.