Atelectasis be bibasal in pattern. Chest CT or Bronchoscopy may be necessary if the cause of atelectasis is not clinically apparent. Direct signs of atelectasis include displacement of interlobar fissures and mobile structures within the thorax, overinflation of the unaffected ipsilateral lobe or contralateral lung, and opacification of the collapsed lobe. Atelectasis may be an acute or chronic condition. In acute atelectasis, the lung has recently collapsed and is primarily notable only for airlessness. In chronic atelectasis, the affected area is often characterized by a complex mixture of airlessness, infection, widening of the bronchi (bronchiectasis), destruction, and scarring (fibrosis). The atmosphere
Sexual differentiation in humans Sexual differentiation in humans Sexual differentiation in humans is the process of development of sex differences in humans. It is defined as the development of phenotypic structures consequent to the action of hormones produced following gonadal determination. Sexual differentiation includes development of different genitalia and the internal genital tracts, breasts, body hair, and plays a role in gender identification. The development of sexual differences begins with the XY sex-determination system that is present in humans, and complex mechanisms are responsible for the development of the phenotypic differences between male and female humans from an undifferentiated zygote. Females have two X