CHEMICAL FACTORS

CHEMICAL FACTORS - saliva, nasal mucus, and tissue fluids....

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
CHEMICAL FACTORS     1. S EBUM ---sebaceous (oil) glands of the skin produce this secretion to help skin and hair retain  moisture. Sebum also forms a protective film that inhibits growth of many pathogenic bacteria  and fungi. By producing a fairly acid pH (3 - 5), sebum discourages growth of many microbes.  Not all microbes are affected this way. Some bacteria are able to break down sebum for nutrients,  and play a big role in producing body odor. These bacteria also are involved in acne.       2. L YSOZYME ---this secretion also interferes with growth of bacteria. It contains enzymes  capable of breaking down cell walls of some bacteria (this is most successful against gram- positive species but can also work against gram-negative). It is found in perspiration, tears, 
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: saliva, nasal mucus, and tissue fluids. 3. G ASTRIC JUICE---this secretion of the gastric glands of the stomach is highly acidic (pH 1.2-3). Most bacteria and bacterial toxins are destroyed by the acidity. Unfortunately, the toxins of Staphylococcus aureus and Clostridium botulinum survive the stomach acid. Pathogens may also pass through the stomach unharmed when they are protected within food particles. One species, Helicobacter pylori, actually lives and grows in the wall of the stomach, causing most ulcers. Vaginal secretions are also somewhat acidic. 4. T RANSFERRINS---found in blood and inhibit microbial growth by reducing the amount of available iron....
View Full Document

Ask a homework question - tutors are online