Hi there :)
I would go with B. a gabbro of minerals.
Sorry if its wrong
-Take Care Now-
`Ans~
Medicine is that branch of science that helps us to know a human body and treat it in the right way to stay healthy as long as possible. So there are different factors which intrigue a person to chose medicine as their career of choice.
<h3><u>Explanation:</u></h3>
Medicine practically deals with knowledge about different disabilities as well as diseases that can attack a person to disturb his normal way of life. And for knowing the diseases, the medical practitioner needs to the normal functions of human body too. This fact attracts many person who are keen to know which mechanisms are going inside their body without even their knowledge.
Medicine also deals with different chemicals and compounds that are actually helpful in curing a disease. Thus, helping a person who is suffering from so much of pain because of a disease is so satisfying. There are many doctors who actually help different poor people who can't afford a good medical treatment. So medicine as a career is full of knowledge and experience, so worth taking as well.
<h2><u>
Heart and lungs:</u></h2>
The upper chamber of the heart is called atrium and lower chamber of the heart is called ventricles.
The blood circulation in the heart is basically under the functioning of three blood vessels namely:
<h3><u>Arteries:
</u></h3>
- They start with the aorta, the huge vein leaving the heart.
- Veins divert oxygen-rich blood from the heart to the majority of the body's tissues.
- They branch a few times, decreasing and littler as they convey blood more remote from the heart.
<h3><u>Capillaries:
</u></h3>
- These are little; flimsy blood vessels that associate the arteries and the veins.
- Their dainty dividers permit oxygen, supplements, carbon dioxide, and other waste items to go to and from our organ's cells.
<h3><u>Veins:
</u></h3>
- These are the blood vessels that return blood to the heart; this blood needs (oxygen-poor) and is wealthy in waste items that are to be discharged or expelled from the body.
- Veins become bigger and bigger as they draw nearer to the heart.
- The unrivaled vena cava is the huge vein that brings blood from the head and arms to the heart, and the second rate vena cava brings blood from the mid-region and legs into the heart.
A pathogen is a microorganism that is able to cause disease in a plant, animal or insect. Pathogenicity is the ability to produce disease in a host organism. Microbes express their pathogenicity by means of their virulence, a term which refers to the degree of pathogenicity of the microbe. Hence, the determinants of virulence of a pathogen are any of its genetic or biochemical or structural features that enable it to produce disease in a host.
The relationship between a host and a pathogen is dynamic, since each modifies the activities and functions of the other. The outcome of such a relationship depends on the virulence of the pathogen and the relative degree of resistance or susceptibility of the host, due mainly to the effectiveness of the host defense mechanisms. Staphylococcus aureus, arguably the most prevalent pathogen of humans, may cause up to one third of all bacterial diseases ranging from boils and pimples to food poisoning, to septicemia and toxic shock. Electron micrograph from Visuals Unlimited, with permission.
The Underlying Mechanisms of Bacterial Pathogenicity
Two broad qualities of pathogenic bacteria underlie the means by which they cause disease:
1. Invasiveness is the ability to invade tissues. It encompasses mechanisms for colonization (adherence and initial multiplication), production of extracellular substances which facilitate invasion (invasins) and ability to bypass or overcome host defense mechanisms.
2. Toxigenesis is the ability to produce toxins. Bacteria may produce two types of toxins called exotoxins and endotoxins. Exotoxins are released from bacterial cells and may act at tissue sites removed from the site of bacterial growth. Endotoxins are cell-associated substance. (In a classic sense, the term endotoxin refers to the lipopolysaccharide component of the outer membrane of Gram-negative bacteria). However, endotoxins may be released from growing bacterial cells and cells that are lysed as a result of effective host defense (e.g. lysozyme) or the activities of certain antibiotics (e.g. penicillins and cephalosporins). Hence, bacterial toxins, both soluble and cell-associated, may be transported by blood and lymph and cause cytotoxic effects at tissue sites remote from the original point of invasion or growth. Some bacterial toxins may also act at the site of colonization and play a role in invasion. Acid-fast stain of Mycobacterium tuberculosis, the agent of tuberculosis (TB). The bacteria are the small pink-staining rods. More than one-third of the world population is infected. The organism has caused more human deaths than any other bacterium in the history of mankind. Although its ability to produce disease is multifactorial, it is not completely understood. American Society of Microbiology, with permission.
