Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Lower Respiratory Tract:
Trachea:
Trachea or windpipe is 12 cm long, 2.5 cm in diameter lying in front of the esophagus and ends opposite the fourth dorsal vertebrae where it divides into main bronchi. It consists of a number of c-shaped rings of cartilage connected byfibrous tissues and having the opening of the C posteriorly. The hnction of the rings of cartilage is to keep trachea open and prevent the collapse of the wall like those of the esophagus. It is lined with ciliated columnar epithelium and cells which secrete mucus.
Bronchi and Bronchioles:
Trachea ends by bifurcating into right and left bronchi at the carina, the level of fourth dorsal vertebra. Each bronchus passes to the corresponding lung. From each main bronchus smaller bronchi are given off, like branches of a tree, and the smallest bronchi is called bronchioles. The structure of the bronchi is similar to that of the bronchi, but they contain no cartilaginous loops, instead there are more muscle fibers. Mucus is secreted by goblet cells interspersed between the ciliated cells and by sub-mucosal mucus-secreting glands.
Each bronchioles terminate in an alveolar sac made up of number of air pockets wihc are lined with delicate layer of flattened epithelial cells and are surrounded by network of capillaries through the walls of which interchange of gasses takes place. Blood in the capillaries is brought by the pulmonary artery from the right ventricle and drained into the left atrium through the pulmonary veins. Alveoli which number 300 millions in adults are minute sacs that arise from the walls of the respiratory bronchioles and alveolar ducts. The alveolus is composed of a single layer of squamous epithelium and elastic basement membrane. These two layers together with the interstitium and the endothelial and basement layers of the adjacent capillary, from the alveolar-capillary membrane or interface. It is across this membrane diffusion of carbon dioxide and oxygen occurs. The structure of millions alveoli provides a large surface area for gaseous diffusion to occur. In addition to this respiratory hnction the alveoli prevent lung collapse by producting surfactant, a phospholipid that decreases surface tension and prevents intersititial fluid from transferring into the lung space.
What are the two divisions of the angiosperms? The angiosperms are separated into monocotyledonous and dicotyledonous. (These categories are defined later in this text.) Pla
Q. Give the biological effects of aflatoxin and List the various natural toxins present in food? Biological effects of aflatoxin include hepatotoxicosis, carcinogenesis and liv
Define the Growth and Development of the infant? Infancy is a period of rapid growth. During the first year of life, the infant grows and develops far more rapidly than at any
Slight or no Metamorphosis In primitive wingless insects (Apterygota) such as spring tails, silver fish etc. and in secondarily apterous insects the young ones which hatch fr
What is Centrioles in cell structure? Most cells of higher organisms contain pairs of cylindrical bodies called centrioles, which help to organize microtubules in cell division
If a person is heterozygous for the 32 allele of the CCR5 gene, how many of the four daughter cells produced by meiosis will have the 32 allele?
Natality - Population Parameters and Regulation Natality is the ability of a population to increase. Natality rate is equivalent to birth rate which means the production of ne
name five animals in it''s trinomial nomenclature.
Q. What is pus? Pus is a residual of the inflammatory reaction and it contains a mixture of fragments of dead infectious agents (generally bacteria), leukocytes and tissues.
Explain Healthcare Burden OF HEART DISEASES? CAD and its complications use up a substantial portion of the scarce healthcare resource of the country. It has been reported that
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd