Gas Exchange In Humans Flashcards
What is the mammalian lung structure made up of?
Lungs, ribcage, trachea, bronchi, bronchioles, alveoli.
Gas exchange in humans?
Gas exchange in mammals is very high as aerobic organisms need a constant supply of oxygen to release ATP. Mammals are large and therefore have a large volume of respite from cells thus a small SA:V ratio. Also they need to maintain a high body temperature which is related to having a high metabolic rate and respiratory rate. Things with a small SA:V ration have a higher metabolic rate and maintain a core body temperature.
Why are lungs located inside the ribcage?
Because air is not sense enough to support and protect them outside the body, they would lose too much water and dry out.
What are the lungs?
A pair of lobed structures made up of bronchioles which end in tiny air sacs called alveoli.
What is the ribcage?
A bony box which can increase and decrease in size using muscles between them and therefore support the ventilation of lungs.
What is the trachea?
A flexible airway made of cartilage. Tracheal walls are made up of muscle lined with ciliates epithelium and goblet cells.
What are the bronchi?
Divisions of the trachea leading to each lung, similar to trachea and produce mucus and contain cilia. Larger bronchi are supported by cartilage.
What are the bronchioles?
Branching sub divisions of the bronchi. Walls are made of muscle lined with epithelial cells. Muscle allows them to construct so they can control air flow in and out of the alveoli.
What’s the alveoli?
Minute air sacs with a diameter of 100 micrometers and 300 micrometers at the end of each bronchioles.
What do the cells lining the trachea and bronchus do?
Protect the alveoli from damage, they are goblet cells which produce mucus to trap microorganisms and dirt and the cilia moves mucus up the trachea.
Define ventilation?
The scientific term for breathing where air pressure rises and falls moving air in and out of the lungs.
What is inspiration?
Also known as inhalation which occurs when air pressure in the atmosphere is greater than that of the lungs, forcing air into the alveoli. High air pressure of atmosphere + low air pressure in lungs = air forced into the alveoli = inspiration.
External intercostal muscle contraction leads to inspiration.
What is expiration?
Also known as exhalation which occurs when air pressure in the atmosphere is lower than that of the lungs, forcing air out of the alveoli. High air pressure of lungs + low air pressure in atmosphere = air forced out of the alveoli = expiration.
Internal intercostal muscles contraction leads to expiration.
What structures allow the changes of pressure?
- the diaphragm which is a sheet of muscle which separates the thorax from the abdomen.
- intercostal muscles which lie between the ribs, there are two sets internal and external.
What occurs during inspiration?
The external intercostal muscles contract pulling the ribs up and out, the internal intercostal muscles relax, the diaphragm contracts and air pressure in the lungs decreases and air movement occurs down a concentration gradient and into the lungs, lung volume increases.
