Unit 2 Compendium Review

Outline:

1. Types of blood vessels

arteries

capillaries

veins

2. cardiovascular system

pulse

blood pressure

3. Blood Types

type a

type b

type ab

type o

4. Microbes and Immunity

microbes

bacteria

viruses

5. Aids

first recognized

how it is transmitted

Types of Blood Vessels

Arteries: The arterial wall has three layers. The innermost layer is a thin layer of cells called endothelium, the middle layer is a relatively thick layer of smooth muscle and elastic tissueand the outer layer is connective tissue. The elastic tissue allows an artery to expand to absorb pressure. Kinda like a balloon when you blow air into it and it expands. When an artery gets clogged it is not a good thing.

Capillaries: Capillaries are extremely narrow microscopic tube with a wall composed only of endothelium with a basement membrane. Their total surface area in humans is about 6,300 square meters. In tissues only certain capillaries are open at any given time.

Veins: The walls of venules have the same three layers as arteries but there is less smooth muscle in the middle layer and less connective tissue in the outer layer. Veins often have valves which allow blood to flow only toward the heart when open and prevent the backward flow of blood when closed.

Cardiovascular System

Pulse: You can feel your pulse by placing your first two fingers on the radial artery which is near the outer border of the palm side of your wrist. The pulse rate is usually 70 beats per minute but it can vary between 60 and 80 beats per minute.

Blood Pressure: Taking blood pressure isn't as easy as it looks. It takes a lot of practice and you have to have good ears also. Blood pressure is the pressure of blood against the wall of a blood vessel. A blood pressure cuff is used to take blood pressure. The highest arterial pressure called the systolic pressure is reached during ejection of blood from the heart. The lowest arterial pressure called the diastolic pressure occurs while the heart ventricles are relaxing. Normal blood pressure for a young adult is 120/80.

Blood Types

Type A Blood- Type A surface antigens; plasma has anti-B antibodies.

Type B Blood- Type B surface antigens; plasma has anti-A antibodies.

Type AB Blood- Both type A and B surface antigens; plasma has neither anti-A nor anti-B antibodies.(universal recipient)

Type O- Neither type A nor type B surface antigens; plasma has both anti-A and anti-B antigens.(universal donor)

Microbes:

Microbes are widely distributed in the environment. They cover inanimate objects and the surfaces of plants and animals; they are on and within our bodies. Microbes perform valuable services, but they also cause diseases. Human infectious diseases are typically caused by bacteria and viruses, collectively called pathogens. The body has three lines of defense against invasion: barriers to entry, such as the skin and mucousmembranes of body cavities, act to prevent pathogens from gaining entrance into the body. First responders, such as the phagocytic white blood cells, act to prevent an infection after an invasion has occurred. Specific defenses overcome an infection by killing the particular disease-causing agent that has entered the body. Specific defenses also protect us against cancer.

Bacteria:

Bacteria are single-celled prokaryotes and they don't have a nucleus. They have three common shapes- a bacillus has a rod shape, a coccus has a spherical shape and a spirillum is curved. Bacteria have a cell wall that contains a unique amino-disaccharide. The cillin antibiotics interfere with thr production of the cell wall. The cell wall of some bacteria is surrounded by a capsule that has a thick gummy consistency. Capsules often allow bacteria to stick to surfacessuch as teeth. They also prevent phagocytic white blood cells from taking them up and destroying them.Bacteria are independent cells that are metabolically competent. Their DNA is packaged in a chromosome that occupies the center of the cell.

Viruses:

Viruses bridge the gap between the living and the nonliving. Outside a host viruses are essentially chemicals that can be stored on a shelf. But when the opportunity arises viruses replicate inside cells and during this period of time they clearly appear to be alive. Viruses are acellular not composed of cells. They are obligate parasites and they do not live independently. Viruses cause disease such as colds, flu, measles, chicken pox, polio, rabies,AIDS, genital warts, and genital herpes. A virus always has two parts- an outer capsid composed of protein units and an inner core of nucleic acid. A virus carries the genetic information needed to reproduce itself.

AIDS:

First recognized as a disease in 1981. It was known to have orginated from chimpanzees. Transmission from chimps to humans probably occured while animals were butchered for food in sub-Suharan Africa with animal blood contaminating wounds of humans. HIV is transimmited through sexual activity enters the bloodstream via mucous membranes lining the vagina, rectum, and mouth. Once HIV has entered the body the immune system initiates anti HIV antibody and cytotoxic T cell production. It can take 6 months for an individual exposed to HIV to produce measurable quantities of antibody. The immune response is weakened as memory T cells are destroyed.

HIV is not transmitted through kissing, hugging, or being in the same room with someone else who has HIV. It has to be blood to blood or sexual intercourse. Today AIDS isn't as big of a deal as TB is. Although people who have bee exposed should be checked for 6 months after the insident.