If the second stimulus is beyond the refractory period, then the second depolarization peak appears before complete repolarization has taken place, which appears like two adjacent peaks. Such double peaks are always followed…
The period of time between the effective refractory period and phase 4 is the ‘relative refractory period’. The refractory period of cardiac muscle is about 250 milliseconds—almost as long as the contraction of the heart.
Summation does not occur in the heart muscle contraction. The refractory period of the heart muscles is longer than that in the skeletal muscles, therefore heart twitches do not overlap and hence increased (summed) ventricular contraction is not seen.
Summation would result in more powerful contraction of the ventricle causing irregular high cardiac output. Heart might find it diffult to recvoer from this ‘double-twitch’, i.e. repolarization might take a long time. This irregular pumping of heart would cause dysrhythmia.
Vagus nerves are the part of para-sympathetic nervous system and act by decreasing the heart rate by direct effect on the SA and AV nodes in the heart atrium. Parasympathetic stimulation by the vagal nerve endings in the atrium results in slowing down of the heart rate and can bring the cardiac output to almost zero.
Vagus nerves are parasympathetic and supply to AV and SA nodes. Parasympathetic stimulation result in decrease in the heart rate and cardiac output. Since the vagal fibers are primarily distributed in the atria, they result in a decrease in the heart rate. Decrease in the heart rate along with slight decrease in ventricular contraction can decrease the cardiac output by 50%.
The cardiac muscle has inherent autorhythmicity, i.e. they can generate the contraction activity automatically. However, the un-stimulated heart beats at a much slower rate and needs continuous sypathetic stimulation to maintain the nornal heart rate, i.e. 70 pulses a minute. Also, sympathetic stimulation increases the power of the ventricular contraction to as much as double the normal, thereby increasing the volume of blood pumped and increasing the ejection pressure. The vagal nerve endings ...
b) While walking at a constant speed with the same container filled with water, the water is at a state of rest. c) After walking in a straight line at a constant speed then making an abrupt right hand turn, the water inside the container will experience turbulence caused by the sudden change of speed.
"Mesomorphs rank high on strength, endurance and agility and therefore is best suited for the above mentioned sports."
A. Hydration Level and DXA Test: Ideally with a decrease in hydration there should be an increase in element content (like Na, K, Cl) leading to a higher molecular weight of the body and thus change in attenuation coefficient.
(American Heart Association, 2008) Body composition tests help us scrutinize and analyze if our body compositions, especially body fats, are at normal and healthy levels. A test such as the blood lactate measurement is used by sport scientists, coaches and athletes to accurately
GFR depends upon a) the difference in the pressure in the afferent arteriole and the glomerulus and b) the total blood flow to the nephrons. Increasing the afferent radius increased the pressure in the glomerulus and
Hyoid bone: easy to locate by moving inferiorly on the neck from below the mandible. Highly mobile bone, easily palpated upon swallowing, especially in males (Drake, Vogl, and Mitchell).
Spinous processes: the relative ease
Spinous processes: the relative ease of location and palpation increases from the cervical, to the thoracic and lumbar spine. Locate the spine and palpate along the edges with the subject recumbent, bony prominences would be felt. Easier in children and in subject 1.
The seed cones are closed before fertilization and after fertilization, they develop into seeds and the scale opens. When the scales near the top of the cone were opened, the seeds were visible and they contained a wing. The