Molecular adaptations to endurance exercise and skeletal muscle fibre plasticity
Adam P. Sharples, James P. Morton, Henning Wackerhage in Molecular Exercise Physiology, 2022
The function of the cardiovascular system is to deliver O2 and nutrients to muscles and other organs, to remove CO2 and other waste products from the tissues, and regulate core temperature and pH. The performance of the system depends on cardiac output, which is the volume of blood pumped by the heart per minute, and the O2 carrying capacity of the blood (red blood cell mass). Since maximal cardiac output (13), and increasing the oxygen carrying capacity (14) correlates with increased V̇O2max, it is widely assumed that oxygen delivery to the working muscle is the primary determinant of V̇O2max. Endurance exercise training increases the volume and the oxygen carrying capacity (red blood cell mass) of the blood (15) and at sea level this plays a small role in increasing V̇O2max; however, this chapter will focus on the adaptations that occur to the heart and skeletal muscle as a result of training.
The Cardiovascular System
Charles Paul Lambert in Physiology and Nutrition for Amateur Wrestling, 2020
The heart and all the blood vessels of the body make up the cardiovascular system. The heart is a four-chambered organ with right and left atria and right and left ventricles. The atria are involved in delivering the blood to the ventricles and the ventricles are involved in the delivery of the blood to the lungs and to the systemic circulation. The circulatory system starts at the largest artery in the body of the aorta. The oxygenated blood is pumped from the left ventricle through the aorta to the systemic circulation. From the aorta the oxygenated blood goes to the arteries, the arterioles which have a muscular precapillary sphincter, and to the capillaries where oxygen/nutrient and CO2/waste exchange occur. After this exchange at the capillary level, deoxygenated blood is returned to the heart by way of the venules, veins, and then great veins. Once the blood reaches the great veins (Superior and Inferior Vena Cava) the blood is then dumped into the right atrium. After the blood is dumped into the right atrium, the blood goes into the right ventricle, and the right ventricle then pumps the blood through the pulmonary artery to the lungs. After the blood goes to the lungs, it comes back to the left atrium and then left ventricle and is then pumped to the systemic circulation as discussed above.
Summary and Development of a New Approach to Senescence
Nate F. Cardarelli in The Thymus in Health and Senescence, 2019
In considering senescence at the superficial level, one observes the results of physiological and mental deterioration. These are manifested as a decrease in cognitive ability, affective disorders, body weight, skin and hair changes, decrease in ability to cope with mental and physiological stress, and the like. Once we have removed the outer layer, which is symptomatology, a closer look reveals the formal causes. Skin changes are characterized by changes in elastin and collagen; muscle wasting and arthritic pains arise from the presence of autoantibodies, senile plaque, and neural tangles; and cell loss in the brain underlies affective disorders and dementias. Infectious diseases of bacterial and viral origin have detrimental effects on kidney, liver, stomach, and gut. Uncontrolled cell growth gives rise to neoplasms that interfere mechanically and chemically with body function. The gradual development of plaque in the cardiovascular system (atherosclerosis) leads to various defects in respiration and nutrient delivery to the cells. The multitude of cause-effect relationships buttressing senescence are fairly well known, and it serves no purpose to dwell on them here.
Developing human tissue engineered arterial constructs to simulate human in vivo thrombus formation
Published in Platelets, 2023
Jacob Ranjbar, Ying Yang, Alan G.S. Harper
The need for such models is critical for enhancing our understanding of the pathological mechanisms and treatment of both arterial and venous thrombosis. Whilst both involve unwanted blood clotting, arterial and venous thrombosis occur in parts of the circulatory system with significantly different structures –Arterial thrombosis is elicited by atherosclerotic plaque formation and rupture, whilst venous thrombosis is elicited by venous stasis within the pockets of venous valves. Thus in vitro models will need to accurately reproduce the differing vascular geometries, rheology, mechanical and cellular properties of the different sides of the blood circulation that contribute to these distinct pathologies. Although there are currently excellent in vitro models to study venous thrombosis currently being produced [19], in this review we will focus on the
Modelling and simulation of fluid flow through stenosis and aneurysm blood vessel: a computational hemodynamic analysis
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2023
J. V. Ramana Reddy, Hojin Ha, S. Sundar
Blood vessels play an important role in the circulatory system; These are in the form of tubes that carry blood between the heart and all parts of the body. The blood vessel size varies enormously; in the case of arteries, it varies from 1 mm to 8 µm while 1 mm to 20 µm for veins. An artery carries oxidized blood away from the heart, whereas a vein is the blood vessel that collects and transports blood toward the heart. The general appearance of the arteries is rounded lumen, while veins are irregular and often collapse. As compared to arteries, veins are thin-walled vessels with a large and irregular lumen. The diseases of arteries, veins, and lymph vessels alert to blood flow disorders that affect circulation, thus resulting in disturbance in organ function. An aneurysm is a pathological condition. It weakens the blood vessel wall due to the bulging area in that area, resulting in an abnormal widening or ballooning more significant than 50% of the standard diameter. The arteries are mostly exposed to an aneurysm rather than a vein among the several blood vessels.
Pulsatile flow of thixotropic blood in artery under external body acceleration
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2023
Louiza Cheffar, Abdelhakim Benslimane, Djamel Sadaoui, Adel Benchabane, Karim Bekkour
In most cases, arteries are assumed to be immobile, i.e. under normal physiological conditions. In this case, blood flow is driven by a biological pump: the heart producing a pulsatile pressure gradient in the cardiovascular system (Shit and Roy 2011). However, this excludes other important situations that occur in daily human life, in which the human body is subjected to external body acceleration, e.g. running, driving a vehicle, traveling in an airplane. A long exposure of body to such acceleration in time can leads to many health problems namely: increase in pulse rate, abdominal pain, venous pooling of blood in the extremities (Frolov et al. 2018). To this end, several researchers (Sud et al. 1983; Misra and Sahu 1988; Srivastava et al. 1994; Massoudi and Phuoc 2008) focused their studies on understanding blood flow in arteries under periodic body acceleration.