Juglar Vein
This vein drains blood from head to heart.
Sub-clavian Vein
This vein drain blood from shoulder to heart.
Plant cells have vacuoles and these can either store useful products or waste products. The cell can get ride of the waste by bringing it to the cell membrane and then the cell membrane closes around the garbage. All of this is possible because of the vacuoles.
Atoms in a molecule are said to be bonded when they share pairs of electrons with each other and this type of bonding is known as covalent bonding. When they share equal number of electrons in a pair and a full electron shell is completed, they become the most stable. But when the electrons are shared unequally by the atoms in a molecule, a POLAR COVALENT BOND is said to be shared by them. This happens as a result of two atoms sharing electron with different electronegativity i.e. the tendency to attract a shared pair of electrons.
The body's first line of defense is actually the non-specific immune system which is also called innate immunity.
Innate immunity employs both physical and chemical barriers that form the first line of defense. These include:
1. The intact skin. The skin is made up of keratin in its outermost layer. Keratin makes skin tough and resistant and pathogens usually cannot penetrate unless the skin is broken.
2. The mucus membrane. This is a thin membrane that forms a protective lining inside many organs and other parts of the body such as the trachea. Mucus produced by the membrane traps bacteria and other harmful particle which are then expelled from the body.
3. Tears. Tears from our eyes contain lysozyme, a chemical that kills bacteria.
If the pathogen gets through or evades these types of defenses, then it is dealt with by the second line of defense which is called specific immunity or acquired immunity. It is here that white blood cells namely the B lymphocytes and T lymphocytes attack, kill or neutralize pathogens.
