<h2>Functions of spleen</h2>
Explanation:
The major functions of spleen besides filtering the blood of foreign materials and phagocytosis of old defective erythrocytes are:
- Initiate immune responses against infections by liberation of antigen and activation of lymphocytes (T and B cells)
- Secretes bactericidal agents which act against invading bacteria
- Secretes interleukins which promote the growth of lymphocytes or antibodies that act against pathogens
- Reservoir: Pools blood by storing thrombocytes, immature erythrocytes.
- Hematopoiesis: Blood cells like erythrocytes, lymphocytes and monocytes develop and mature in spleen especially during the early fetal life.
A lack of blood flow determines the number of cell layers that can
survive when they are transplanted
nucleic acids. certain proteins. cell membranes. certain carbohydrates.
Astronomy can best be described as a "<span>a. study of objects beyond earths atmosphere", although the subject of astronomy can be much more complicated. </span>
The skin is composed of thin membranous tissue that is quite permeable to water and contains a large network of blood vessels. The thin membranous skin is allows the respiratory gases to readily diffuse directly down their gradients between the blood vessels and the surroundings. When the frog is out of the water, mucus glands in the skin keep the frog moist, which helps absorb dissolved oxygen from the air.
A frog may also breathe much like a human, by taking air in through their nostrils and down into their lungs. The mechanism of taking air into the lungs is however sligthly different than in humans. Frogs do not have ribs nor a diaphragm, which in humans helps serve in expand the chest and thereby decreasing the pressure in the lungs allowing outside air to flow in.
In order to draw air into its mouth the frog lowers the floor of its mouth, which causes the throat to expand. Then the nostrils open allowing air to enter the enlarged mouth. The nostrils then close and the air in the mouth is forced into the lungs by contraction of the floor of the mouth. To elimate the carbon dioxide in the lungs the floor of the mouth moves down, drawing the air out of the lungs and into the mouth. Finally the nostrils are opened and the floor of the mouth moved up pushing the air out of the nostrils.
Frogs also have a respiratory surface on the lining of their mouth on which gas exchange takes place readily. While at rest, this process is their predominate form of breathing, only fills the lungs occasionally. This is because the lungs, which only adults have, are poorly developed.
