4 Flashcards
Systole versus diastole + cardiac cycle
Cardiac cycle events can be divided into systole and diastole. During systole, blood pressure increases and the cardiac muscles contract. During diastole, blood pressure decreases and the cardiac muscles relax. Additionally, the cardiac cycle begins with atrial systole, then atrial diastole, then ventricular systole, then the semilunar valves close to prevent backflow, then ventricular diastole.
Sympathetic versus parasympathetic nervous system
The sympathetic nervous system releases hormones such as epinephrine to accelerate the heart rate. The parasympathetic nervous system releases the hormone acetylcholine to slow the heart rate.
Types of pathogens
The types of pathogens include parasitic worms (ex: tapeworms), parasitic protozoa (ex: amoebas), fungi (ex: mold), eubacteria (ex: e. coli), viruses (ex: HIV), and prions (ex: mad cow disease).
How are pathogens removed from the body?
Some ways that pathogens are removed from the body are through the shedding of skin cells, coughing, and the flushing of bodily fluids.
Mucous membranes
Mucous membranes act as physical barriers for exposed areas of the body. These membranes secrete sticky mucus containing enzymes, glycoproteins and lysozymes, that attack bacterial cell walls. They have antiseptic properties that reduce the growth of microbes.
Blood clotting
Blood clotting is a result of multiple reactions that are triggered by damage to a blood vessel. First, inactive clotting factors are activated by platelets. This triggers the conversion of inactive prothrombin into active thrombin. Then, thrombin catalyzes the reaction that converts soluble fibrinogen into insoluble fibrin. The fibrin then creates a clump of blood to form a clot.
B cells/lymphocytes
A B cells/lymphocytes secrete antibodies with the help of plasma B cells. The antibodies are attached to the B cell’s surface and have unique binding sites. When the B cell encounters an antigen, the B cells divide through mitosis to create multiple copies of itself. These copies become memory B cells so your immune system can recognize the antigens in the future.
T cells/lymphocytes
T cells/lymphocytes help destroy pathogens. The APC (Antigen Presenting Cell) traps the antigen and presents it to the T helper cell. Once the antigen has been recognized by the T helper cell, it triggers the production of antibodies and activates macrophages to engulf and destroy the antigen.
Florey & Chain
After the discovery of penicillin by Fleming, Florey & Chain infected 8 mice with pneumonia. Then, 4 out of 8 of the mice were injected with penicillin. The mice that were not treated died within 24 hours, while the mice that were treated survived. Florey & Chain then tested penicillin on infected human patients and most patients survived.
Antibiotic/antibiotic resistance
An antibiotic is a medicine that inhibits the growth of or destroys bacteria by destroying its cell wall. Antibiotics are ineffective against viruses because they do not have a cell wall for it to attack. In some cases, bacteria can exchange genes coding for antibiotic resistance and develop resistance to multiple antibiotics. An example of multidrug resistant bacteria is staphylococcus aureus.
Anaerobic respiration
Anaerobic respiration occurs in the cytoplasm as it involves only glycolysis. The two types of anaerobic respiration are alcoholic fermentation, which occurs in yeast, and lactic acid fermentation, which occurs in animal muscle cells. Anaerobic respiration produces a smaller amount of ATP than aerobic respiration.
Vaccinations
Vaccinations inject a weakened form of the pathogen into the body to ensure primary defense is triggered, but the disease is not contracted.
Histamine and antihistamine
Histamine is produced by white blood cells (basophils and mast cells). Its function is to dilate and increase permeability of capillaries. This enables white blood cells to invade infected tissues and engage allergens in the form of itchiness, swelling, and sneezing, for example. Antihistamines are drugs that inhibit the action of histamines by blocking histamine’s receptors.
Non-specific/innate immunity
Non-specific/innate immunity is the first line of defense. It does not distinguish one pathogen from another. Its response is rapid because it’s present before any exposure to pathogens. The response is short and it does not result in any immune memory. Some examples are macrophages and the skin.
Specific/adaptive immunity
The specific response is the second line of defense. It responds to a specific pathogen type. Its response is slower because it requires specialized cells/structures to be activated. The duration of the response is longer and builds immune memory. Some examples are B cells and T cells.
