Midterm 1- Lesson 1-3 Flashcards
Discuss the role of blood as a transport system.
Blood carries oxygen from the lungs to the tissues and carbon dioxide, excreted as expired air, from the tissues to the lungs. Blood also carries nutrients from the digestive tract to the individual cells so that the cells can extract nutrients for growth and energy. The blood carries waste products from the cells to the kidneys, from which the waste is excreted in the urine. It also carries hormones from the endocrine glands to other organs of the body and transports heat to the surface of the skin to control body temperature.
Explain how the arteries and veins differ in their functions.
The arteries carry blood from the heart to other organs and tissues, where oxygen and nutrients are transported through the arterioles (tiny branches of the arteries) and the capillaries (smaller vessels that branch off from the arteries) to individual cells. Veins, on the other hand, return the deoxygenated blood to the heart.
Distinguish between the systole and diastole phases of the cardiac cycle:
The heart performs regular rhythmic phases of contraction and relaxation knows as the cardiac cycle. There are two phases in the cardiac cycle, systole and diastole. During systole, blood is pumped out of the heart, and blood pressure in the blood vessels increases. During diastole, blood pressure drops and blood is taken into the heart as the muscles of the heart relax.
Identify the factors that affect heart rate.
During exercise, emotional excitement, or stress, the heart speeds up and the cardiac cycle is completed in a shorter time. Most of this speedup comes out of the diastolic period so that a chronically rapid heart rate reduces overall time for rest. Consequently, a chronically or excessively rapid heart rate can decrease the heat’s strength, which may reduce the volume of blood that is pumped.
Heart rate is also regulated by the amount of blood flowing into the veins. The larger the quantity of blood available, the harder the heart will have to pump. On the other hand, a lower supply of blood leads to a weaker and less frequent heartbeat.
Atherosclerosis
This heart disease is caused by deposits of cholesterol and other substances on the arterial walls, which form plaques that narrow the arteries. Tissue damage occurs when the presence of atherosclerotic plaques reduces the flow of blood through the arteries and interferes with the passage of nutrients from the capillaries into the cells. Poor health habits such as smoking and a high-fat diet have led to two primary clinical manifestations associated with atherosclerosis:
o Angina pectoris, or chest pain, occurs because the muscle tissue of the hear must continue its activity without a sufficient supply of oxygen or adequate removal of carbon dioxide and other waste products.
o Myocardial infarction is most likely to occur when a clot has developed in a coronary vessel and blocks the flow of blood to the heart. A myocardial infarction, also known as a heart attack, can cause death.
Angina pectoris
or chest pain, occurs because the muscle tissue of the hear must continue its activity without a sufficient supply of oxygen or adequate removal of carbon dioxide and other waste products.
Myocardial infarction
most likely to occur when a clot has developed in a coronary vessel and blocks the flow of blood to the heart. A myocardial infarction, also known as a heart attack, can cause death.
Arteriosclerosis
a vessel disorder that hardens the arteries, and results when calcium, slats, and scar tissue react with the elastic tissue of the arteries. The consequence is to decrease the elasticity of the arteries, making them rigid and hard. Blood pressure then increases because the arteries cannot dilate and constrict to help blood move, and hypertension (high blood pressure) may result.
Phlebitis
a disorder that produces inflammation of a vein wall, often accompanied by water retention and pain. The condition typically results from an infection surrounding the vein, from varicose veins, from pregnancy-related bodily changes, or from the pressure of a tumor on the vein. The chief threat posed by phlebitis is that it can encourage the production of blood clots, which then block circulation.
Varicose veins
are superficial veins that have become dilated or swollen. Typically, veins in the lower extremities of the body are most susceptible because they are subjected to great pressure from the force of gravity.
Rheumatic Fever
a bacterial infection that originated in the connective tissue and can spread to the heart, potentially affecting the functioning of the heart valves. The flaps of the valves may be changed into rigid, thickened structures that interfere with the flow of blood between the atrium and the ventricle. People with rheumatic fever, or with congenital heart disease, are particularly vulnerable to endocarditis, the inflammation of the membrane that lines the cavities of the heart, which is caused by staphylococcus or streptococcus organisms
anemia
a condition in which the number of red blood cells or amount of hemoglobin is below normal. Through loss of blood, much vital iron (essential for the production of hemoglobin) is lost. Iron supplements must sometimes be taken to offset this problem. Other forms of anemia, including aplastic anemia, may occur because the bone marrow is unable to produce a sufficient number of red blood cells. The result if a decrease in the blood’s transport capabilities, causing tissues to receive too little oxygen and to be left with to much carbon dioxide.
Erythrocytosis
a disorder characterized by an excess of red blood cells. It may result from a lack of oxygen in the tissues or as a secondary manifestation of other diseases. It also increases the viscosity of the blood and reduces the rate of blood flow.
sickle-cell anemia
a disease related to red blood cell production. A genetically transmitted inability to produce normal red blood cells. These cells are sickle-shaped instead of flattened spheres, and they contain abnormal hemoglobin.
Hemophilia
: a clotting dysfunction that affects individuals who are unable to produce thromboplastin and fibrin. Therefore, their blood cannot clot naturally in response to injury, and they may bleed to death unless they receive medication.
Identify the factors that influence blood pressure (3)
- Cardiac output: Pressure against the arterial walls is greater as the volume of blood flow increases.
- Peripheral Resistance: the resistance to blood flow in the small arteries of the body (arterioles). Peripheral resistance is influenced by the viscosity (thickness) of the blood – specifically, the number of red blood cells and the amount of plasma the blood contains.
- Highly viscous blood produces higher blood pressure
2 components of blood
- ) plasma
2. ) blood cells
plasma
is the fluid portion of blood, occupying approximately 55% if the blood volume. The blood cells are suspended in the plasma, which contains plasma proteins and plasma electrolytes (salts) plus the substances that are being transported by the blood (oxygen and nutrients or carbon dioxide and waste materials).
