Atelectasis from the outside (tumor, lymph node, tubercle). Another cause is poor surfactant spreading during inspiration, causing the surface tension to be at its highest which tends to collapse smaller alveoli. Atelectasis may also occur during suction, as along with sputum, air is withdrawn from the lungs. There are several types of atelectasis according to their underlying mechanisms or the distribution of alveolar collapse; resorption, compression, microatelectasis and contraction atelectasis. Relaxation atelectasis (also called passive atelectasis) is when a pleural effusion or a pneumothorax disrupts the contact between the parietal and visceral pleurae. Risk factors associated with increased likelihood of the
Thermoregulation in humans are impermeable to sweat and thus do not facilitate heat loss through evaporation can actually contribute to heat stress. Adjusting the human body temperature downward has been used therapeutically, in particular, as a method of stabilizing a body following trauma. It has been suggested that adjusting the A1 receptor of the hypothalamus may allow humans to enter a hibernation-like state of reduced body temperature, which could be useful for applications such as long-duration space flight. Humans output from 70 watts to 870 watts, depending on the amount of physical activity undertaken. Thermoregulation in humans As in other mammals, thermoregulation in