capillaries
Capillaries are the blood vessels that surround the alveoli, or air sacs, in your lungs. These capillaries are the site of gas exchange.
The air sacs send oxygen to the cells.
kidney glomeruli, air sacs of the lungs, lining of the heart, blood vessels, and lymphatic vessels, lining of the ventral cavity (serosae).
air sacs are in the lungs and when you breathe in blood carries it to the lungs.
lungs
Capillaries . The smallest of the blood vessels: capillaries.
A lot of the lung tissue can be damaged by smoking, but you seem to be asking about the alveoli (singular = alveolus). These are small sacs surrounded by blood vessels that are located at the end of the various branches of the air passageways inside the lungs.
Because the air sacs carry oxygen to the blood!
They are the alveoli.
The lungs take in oxygen, this oxygen travels down to the alveoli (thin, permeable sacs), which are covered in blood vessels, and the oxygen travels into the blood due to a pressure difference and CO2 goes from the blood to the lungs to be exhaled. The body needs that oxygen for almost every system in the body.
# Oxygen and carbon dioxide travels to and from tiny air sacs in the lungs, through the walls of the capillaries, into the blood. Once blood travels through the pulmonic valve, it enters your lungs. This is called the pulmonary circulation. From your pulmonic valve, blood travels to the pulmonary artery to tiny capillary vessels in the lungs. Here, oxygen travels from the tiny air sacs in the lungs, through the walls of the capillaries, into the blood. At the same time, carbon dioxide, a waste product of metabolism, passes from the blood into the air sacs. Carbon dioxide leaves the body when you exhale. Once the blood is purified and oxygenated, it travels back to the left atrium through the pulmonary veins.
Capillaries The smallest of the blood vessels: capillaries.