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.
Ice age is an interval of geologic time between 2 million and 10,000 years ago during that period the northern hemisphere experienced several episodes of continental glacial advan
in natural vegetative propagation which structure gives rise to new individuals?
MICROBODIES Single unit membrane bound small spherical structures. Microbodies are structurally related to lysosome. On the basis of functions microbodies are of four typ
Equine herpes virus infections (equine rhinopneumonitis, abortions) Equine herpes virus infections in horses and foal are caused by Alphaherpes virus of herpesviridae family p
A simple osmometer Remove the bottom from a small glass bottle about 2.5 cm in diameter. Fit a one-hole stopper tightly into the bottom and put a 50 cm length of glass tubing o
Explain the concpet of Dressing Dressing: Means medicine wound covering; a bandage or other sterile covering is put on a wound to protect it from infection or further damage.
Ovule The ovule, also known as the megasporangium is the forerunner of the seed. It consists of a central mound of tissue called the nucellus, which is enveloped by one or tw
Q. What are the major representatives of the pteridophytes? Is this plant group phanerogamic or cryptogamic? The better known pteridophytes are the ferns and the maidenhairs, f
#qwhy is it necessary to grind the foo sample before testing uestion..
Q. Explain Spoilage by fungi and bacteria? The dominant spoilage organisms in fruits are fungi, as their pH is low (normally 5),whereas the pH of vegetables is fiom 5.0 to 7
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