Bio 208 Exam III

According to Starling's law of the heart, the cardiac output is directly related to venous return. This means that the amount of blood returning to the heart from the veins has a direct impact on the volume of blood pumped out by the heart per minute. When there is an increase in venous return, the heart stretches and contracts more forcefully, resulting in an increase in cardiac output. Conversely, a decrease in venous return leads to a decrease in cardiac output. Therefore, venous return plays a crucial role in regulating cardiac output.

Anemia is a condition characterized by a decrease in the number of red blood cells or a decrease in their ability to carry oxygen. Hematocrit is a measure of the volume of red blood cells in the blood. A hematocrit value of less than 40 indicates a lower than normal concentration of red blood cells, which can lead to anemia. Therefore, anemia is most closely associated with a hematocrit value of less than 40.

Parathyroid hormone is the correct answer because it acts as the antagonist of calcitonin. Calcitonin is responsible for lowering blood calcium levels, while parathyroid hormone works to increase blood calcium levels. These two hormones have opposing effects on calcium regulation in the body, making parathyroid hormone the antagonist of calcitonin.

The spleen is the largest collection of lymphatic tissue in the adult body. It is responsible for filtering and removing old or damaged red blood cells, as well as producing and storing white blood cells to help fight off infections. The spleen also plays a role in immune responses by producing antibodies and removing bacteria and other foreign substances from the bloodstream.

A heart sound is heard when the valves close. This is because the closing of the valves creates a turbulent flow of blood, which produces the sound. The closure of the valves prevents the backflow of blood and ensures that blood flows in the correct direction through the heart.

The given symptoms of a thin, nervous patient with protruding eye balls are characteristic of Graves disease. Graves disease is an autoimmune disorder that affects the thyroid gland, causing it to produce excessive amounts of thyroid hormones. This leads to symptoms such as weight loss, nervousness, and bulging eyes (exophthalmos). Therefore, the correct answer is that the patient suffers from Graves disease.

Insulin-dependent diabetes mellitus, also known as Type I diabetes, is characterized by the body's inability to produce insulin. This type of diabetes requires the use of insulin injections or an insulin pump to regulate blood sugar levels. It is different from non-insulin dependent diabetes (Type II diabetes), which typically occurs later in life and can often be managed with lifestyle changes and oral medications. Type III diabetes and diabetes insipidus are unrelated conditions and not alternative names for insulin-dependent diabetes mellitus.

Erythropoietin (EPO) is the correct answer because it is a hormone that primarily regulates the production of red blood cells (RBCs). EPO is produced by the kidneys in response to low oxygen levels in the body. It stimulates the bone marrow to produce more RBCs, which helps to increase the oxygen-carrying capacity of the blood. Thymosin, angiotensin, ACTH, and LH do not play a significant role in the regulation of RBC production.

Histamine is a chemical released by mast cells during inflammation. It causes vasodilation, which increases blood flow to the area, leading to redness and heat. Histamine also increases vascular permeability, allowing fluid and proteins to leak into the tissue, resulting in swelling. This increased permeability also facilitates the localization of proteins and cells necessary for the body's defense mechanisms. Therefore, all of the given changes (redness, swelling, heat, localization of proteins and cells) occur during inflammation due to the actions of histamine.

Ventricular diastole refers to the relaxation of the ventricles and the filling of the atria. During this phase of the cardiac cycle, the ventricles are relaxed and blood flows from the atria into the ventricles. This is an important part of the cardiac cycle as it allows the ventricles to fill with blood before they contract during ventricular systole. Ventricular diastole is essential for maintaining proper blood flow and ensuring efficient cardiac function.

Excessive immune responses to antigens are characteristic of allergies. Allergies occur when the immune system overreacts to substances that are normally harmless, such as pollen, dust mites, or certain foods. The immune system mistakenly identifies these substances as threats and releases chemicals, such as histamine, which cause symptoms like sneezing, itching, and swelling. Unlike immunodeficiency diseases or HIV infection, allergies do not involve a weakened immune system. Similarly, while allergies can occur in people of any age, they are not specifically common in the elderly. Therefore, the correct answer is allergies.

When the diameter of blood vessels decreases, it leads to vasoconstriction, which restricts blood flow to the tissue. This reduces the amount of blood reaching the tissue and therefore does not result in increased blood flow. The other options, such as increased blood volume, increased blood pressure, decreased peripheral resistance, and relaxation of precapillary sphincters, all contribute to increased blood flow to the tissue in different ways.

The basilar membrane is the structure that separates the cochlear duct from the tympanic duct. It is a thin, flexible membrane that runs along the length of the cochlea. When sound waves enter the cochlea, they cause vibrations in the basilar membrane. These vibrations are then converted into electrical signals by the hair cells in the organ of Corti, which is located on top of the basilar membrane. These electrical signals are then sent to the brain, where they are interpreted as sound.

Dark current refers to the movement of sodium ions into photoreceptors in complete darkness. In the absence of light, photoreceptors are depolarized and continuously release neurotransmitters, which allows for the detection of low levels of light. This depolarization is maintained by a constant influx of sodium ions into the photoreceptors through ion channels.

Excess secretion of growth hormone after puberty can lead to acromegaly. Acromegaly is a condition characterized by the enlargement of bones and tissues, particularly in the hands, feet, and face. This occurs because the growth plates in the bones have already closed after puberty, preventing longitudinal growth. Instead, the excess growth hormone causes the bones and tissues to thicken and enlarge. Symptoms of acromegaly include enlarged facial features, enlarged hands and feet, joint pain, and organ enlargement.

Plasma cells are responsible for the production of circulating antibodies. These cells are a type of B lymphocyte that has been activated by an antigen. Once activated, plasma cells produce large amounts of antibodies that are released into the bloodstream, where they can bind to and neutralize pathogens or foreign substances. This immune response helps to eliminate infections and protect the body from harmful invaders. NK cells, helper T cells, cytotoxic T cells, and suppressor T cells have different roles in the immune system, but they are not directly involved in the production of antibodies.

The heart valve occurring between the LA and LV is called the mitral (bicuspid) valve. This valve is located between the left atrium (LA) and the left ventricle (LV) and is composed of two flaps or cusps, hence the term "bicuspid." It prevents the backflow of blood from the LV to the LA during ventricular contraction, ensuring that blood flows in one direction through the heart.

Cardiac output is a measure of the amount of blood pumped by the heart per minute. It is determined by multiplying the heart rate (the number of times the heart beats per minute) by the stroke volume (the amount of blood pumped by the heart with each beat). This calculation reflects the total volume of blood circulated by the heart in a given time period. Therefore, the correct answer is "the product of heart rate and stroke volume."

The spleen is responsible for the breakdown of aged and damaged red blood cells (RBCs). It filters the blood and removes old or damaged RBCs from circulation. The spleen contains specialized cells called macrophages, which engulf and break down the RBCs. This process helps to remove any RBCs that are no longer functioning properly and allows for the recycling of their components. The other options, such as the yellow bone marrow, kidneys, digestive tract, and thymus gland, do not play a significant role in the breakdown of RBCs.

Blood osmotic pressure is primarily determined by the concentration of plasma proteins. Osmotic pressure is the force that helps maintain the balance of fluids between the blood vessels and the surrounding tissues. Plasma proteins, such as albumin, exert a significant osmotic effect by attracting water molecules and preventing excessive fluid loss from the blood vessels into the tissues. Therefore, any changes in the concentration of plasma proteins can directly impact blood osmotic pressure. Changes in the concentration of plasma sodium ions, waste glucose, waste proteins, or the number of white blood cells do not have as significant an effect on blood osmotic pressure.

FSH, or follicle-stimulating hormone, is the pituitary hormone that promotes egg development in ovaries and sperm development in testes. In females, FSH stimulates the growth and maturation of ovarian follicles, which contain the eggs. In males, FSH stimulates the production of sperm in the testes. Therefore, FSH plays a crucial role in the reproductive processes of both males and females.

The left and right pulmonary veins carry oxygenated blood from the lungs back to the heart. The left pulmonary veins specifically carry blood from the left lung, while the right pulmonary veins carry blood from the right lung. This oxygenated blood is then pumped into the left atrium of the heart, which acts as a receiving chamber for blood returning from the lungs. From the left atrium, the blood is then pumped into the left ventricle, which is responsible for pumping blood out to the rest of the body. Therefore, the correct answer is left atrium.

An embolus is a drifting blood clot that travels through the bloodstream and can potentially block blood vessels in different parts of the body. Unlike a thrombus, which is a stationary blood clot, an embolus can break off from its original location and cause a blockage elsewhere. This can lead to serious health issues if the embolus blocks a vital blood vessel, such as in the heart or brain. Therefore, out of the given options, embolus is the correct term for a drifting blood clot.

Adrenaline is an example of a hormone that functions as a vasoconstrictor. When released into the bloodstream, adrenaline causes the blood vessels to constrict or narrow. This constriction helps to increase blood pressure and redirect blood flow to vital organs and muscles, preparing the body for a "fight or flight" response. By constricting blood vessels, adrenaline helps to ensure that blood is delivered efficiently to areas of the body that need it most during times of stress or danger.

Kwashiorkor Edema is a form of protein-energy malnutrition that occurs due to inadequate protein intake. It is characterized by a lowering of plasma protein levels, which leads to a decrease in osmotic pressure. This decrease in osmotic pressure causes an increase in interstitial volume, resulting in the accumulation of fluid in the tissues and the development of edema. Although edema can occur due to various reasons, it is not caused by a blockage of lymphatic ducts in the case of Kwashiorkor Edema.

Thalassemia is a genetic disorder that affects the production of red blood cells (RBCs). It is characterized by abnormal hemoglobin production, leading to a reduced number of RBCs and impaired oxygen-carrying capacity. This condition can result in anemia and other complications. Hemophilia is a bleeding disorder, diapedesis is the process of RBCs squeezing through blood vessel walls, hemostasemia is not a recognized medical term, and leukemia is a cancer of the blood and bone marrow. Therefore, thalassemia is the most closely associated with the inability to produce proper RBCs.

The cochlea is responsible for discriminating different pitches of sounds. This is achieved by stimulating or vibrating different patches of the basilar membrane. As sound waves travel through the cochlea, they cause specific areas of the basilar membrane to vibrate based on their frequency. This vibration stimulates the hair cells located on the membrane, which then send electrical signals to the brain for interpretation. By stimulating different patches of the basilar membrane, the cochlea can differentiate between different frequencies and allow us to perceive different pitches of sounds.

The adrenal cortex is responsible for releasing steroids into the bloodstream. Steroids are hormones that play a crucial role in regulating various bodily functions, including metabolism, immune response, and stress response. The adrenal cortex produces hormones like cortisol, aldosterone, and sex hormones, which are all types of steroids. These hormones are released into the bloodstream and transported to different parts of the body to exert their effects. Therefore, the adrenal cortex is the correct answer as it is the specific gland that releases steroids into the bloodstream.

When the heart is an insufficient pump, it is unable to effectively pump blood throughout the body. This can lead to a backup of blood in the veins, causing an increase in pressure within the capillaries. This increased pressure can force fluid out of the capillaries and into the surrounding tissues, resulting in the formation of edema. Edema is the accumulation of excess fluid in the interstitial spaces, causing swelling and discomfort.

Serum is the liquid portion of blood that remains after the clotting proteins have been removed from plasma. It is similar to blood plasma but does not contain the proteins involved in blood clotting. Therefore, the correct answer is "is plasma minus the clotting proteins."

IgE is the correct answer because immunoglobulins that attach to mast cells and basophils and are involved in allergic reactions are IgE. IgE plays a crucial role in triggering the release of histamine and other chemicals that cause allergic symptoms such as itching, swelling, and inflammation. It is responsible for immediate hypersensitivity reactions, such as hay fever, asthma, and anaphylaxis. IgA, IgD, IgG, and IgM are involved in different immune responses but are not specifically associated with allergic reactions involving mast cells and basophils.

B cells are primarily activated by the activities of helper T cells. Helper T cells play a crucial role in the immune response by recognizing antigens presented by antigen-presenting cells (such as macrophages) and activating B cells. Upon activation, B cells differentiate into plasma cells, which produce antibodies specific to the antigens. Therefore, while antigens, antibodies, macrophages, and plasma cells are all involved in the immune response, it is the helper T cells that primarily activate B cells.

In response to hemorrhage, there is mobilization of venous reserve. This means that the body will increase the amount of blood stored in the veins in order to compensate for the loss of blood due to hemorrhage. This helps to maintain blood pressure and ensure that enough blood is available for circulation. The other options, increased parasympathetic stimulation of the heart and decreased vasomotor tone, may also occur in response to hemorrhage, but they are not the only responses and do not encompass all the possible physiological changes that can occur. Therefore, the correct answer is mobilization of venous reserve.