1.
1. The hypothalamic-hpophyseal tract:
Correct Answer
D. Is partly contained within the infundibulum
Explanation
The hypothalamic-hypophyseal tract is a connection between the hypothalamus and the pituitary gland. It is responsible for transporting hormones from the hypothalamus to the pituitary gland. The infundibulum is a structure that connects the hypothalamus to the pituitary gland, and it contains a portion of the hypothalamic-hypophyseal tract. Therefore, the statement "is partly contained within the infundibulum" is a correct explanation.
2.
The immediate response to blood vessel injury is:
Correct Answer
C. Vascular spasm
Explanation
The immediate response to blood vessel injury is vascular spasm. When a blood vessel is injured, the smooth muscles in the vessel walls contract, causing the vessel to constrict. This constriction helps to reduce blood flow to the injured area and minimize bleeding. Vascular spasm is the first step in the process of hemostasis, which is the body's mechanism for stopping bleeding.
3.
Which of the following is true about Calcium homeostasis?
Correct Answer
D. Parathyroid hormone is the single most important regulator of calcium levels in the blood.
Explanation
Parathyroid hormone is the single most important regulator of calcium levels in the blood. This hormone is released by the parathyroid glands in response to low blood calcium levels. It acts on the bones, kidneys, and intestines to increase calcium levels in the blood. It stimulates osteoclasts to break down bone tissue, releasing calcium into the bloodstream. It also enhances the reabsorption of calcium in the kidneys and promotes the activation of vitamin D, which aids in the absorption of calcium from the intestines. Overall, parathyroid hormone plays a crucial role in maintaining calcium homeostasis in the body.
4.
The hormone that triggers ovulation of an egg from the female ovary is:
Correct Answer
D. Luteinizing hormone
Explanation
Luteinizing hormone is the correct answer because it is responsible for triggering ovulation in females. During the menstrual cycle, luteinizing hormone levels increase, causing the release of an egg from the ovary. This hormone plays a crucial role in the reproductive system and is essential for fertility. Follicle-stimulating hormone, prolactin, and progesterone have important roles in the reproductive system but do not directly trigger ovulation.
5.
Which of the following is not a cause of bleeding disorders?
Correct Answer
C. Excess secretion of platelet-derived growth factor (PDGF)
Explanation
Excess secretion of platelet-derived growth factor (PDGF) is not a cause of bleeding disorders. Bleeding disorders can be caused by thrombocytopenia, which is a decrease in circulating platelets, a defect in the clotting cascade, and vitamin K deficiency. PDGF is a protein that plays a role in cell growth and division, but it is not directly involved in the clotting process or platelet function. Therefore, excess secretion of PDGF does not contribute to bleeding disorders.
6.
Which of the following is not a formed element
Correct Answer
C. Plasma
Explanation
Plasma is not a formed element because it is a component of blood that is not a cell. It is the liquid portion of blood that carries various substances, such as nutrients, hormones, and waste products. Formed elements, on the other hand, are the cellular components of blood, including red blood cells (erythrocytes), white blood cells (leucocytes), and platelets.
7.
The special type of hemoglobin preent in fetal red blood cells is:
Correct Answer
A. Hemoglobin F
Explanation
Hemoglobin F is the correct answer because it is the special type of hemoglobin found in fetal red blood cells. This type of hemoglobin has a higher affinity for oxygen than adult hemoglobin, allowing the fetus to efficiently extract oxygen from the mother's blood through the placenta. Hemoglobin S is associated with sickle cell disease, hemoglobin A is the predominant type in adult red blood cells, and hemoglobin B is not a recognized type of hemoglobin.
8.
Prostaglandins are:
Correct Answer
C. Lipid hormones manufactured in cell plasma membranes
Explanation
Prostaglandins are lipid hormones that are synthesized in the cell plasma membranes. They are derived from fatty acids and play a crucial role in various physiological processes, including inflammation, blood clotting, and pain sensation. Being lipid-based, prostaglandins can easily diffuse across cell membranes to exert their effects locally.
9.
Select the correct statement about equilibrium.
Correct Answer
A. Cristae respond to angular acceleration.
Explanation
The correct statement about equilibrium is that Cristae respond to angular acceleration.
10.
Place the following in correct developmental sequence:1. reticulocyte2. proerythroblast3. normoblast4. late erythroblast
Correct Answer
A. 2, 4, 3, 1
Explanation
The correct developmental sequence for the given cells is as follows: proerythroblast (2), late erythroblast (4), normoblast (3), reticulocyte (1). This sequence represents the progression of red blood cell development, starting with the proerythroblast which is an early precursor cell, followed by the late erythroblast which is a more mature precursor cell, then the normoblast which is even more mature, and finally the reticulocyte which is the final stage before the red blood cell is fully matured and released into the bloodstream.
11.
Virtually all of the protein or amino acid-based hormones exert their effects through intracellular:
Correct Answer
B. Second messengers
Explanation
Protein or amino acid-based hormones typically cannot enter cells directly, so they exert their effects through second messengers. Second messengers are molecules that transmit signals from the hormone receptor on the cell surface to the inside of the cell, where they can trigger various cellular responses. These second messengers can include molecules such as cyclic adenosine monophosphate (cAMP), calcium ions, or inositol triphosphate (IP3). By utilizing second messengers, protein or amino acid-based hormones can efficiently and rapidly communicate signals within cells and regulate various physiological processes.
12.
Which of the following is a protective function of blood?
Correct Answer
C. Prevention of blood loss
Explanation
The protective function of blood is the prevention of blood loss. Blood contains platelets and clotting factors that work together to form a clot and stop bleeding when a blood vessel is damaged. This clotting process helps to prevent excessive blood loss and promotes the healing of the injured blood vessel.
13.
Which sequence is correct for the following events:1. fibrinogen -- fibrin2. clot retraction3. formation of thromboplastin4. prothrombin -- thrombin
Correct Answer
D. 3, 4, 1, 2
Explanation
The correct sequence for the events is: 3. formation of thromboplastin, 4. prothrombin -- thrombin, 1. fibrinogen -- fibrin, 2. clot retraction. Thromboplastin is formed first, which then converts prothrombin into thrombin. Thrombin then acts on fibrinogen to form fibrin, which is the main component of a blood clot. Finally, clot retraction occurs, which is the process of the clot shrinking and becoming more compact.
14.
The eye muscle that elevates and turns the eye laterally is the:
Correct Answer
D. Inferior oblique
Explanation
The correct answer is the inferior oblique. This muscle is responsible for elevating and turning the eye laterally. The superior oblique muscle is responsible for depressing and turning the eye laterally. The lateral rectus muscle is responsible for turning the eye laterally, while the medial rectus muscle is responsible for turning the eye medially.
15.
Which of the following is NOT an action of the catecholamines:
Correct Answer
E. Decreased blood pressure
Explanation
Catecholamines, such as adrenaline and noradrenaline, are known for their role in the "fight or flight" response. They typically cause an increase in heart rate, stimulate the sympathetic nervous system, and increase blood glucose levels to provide energy during stressful situations. However, they do not cause a decrease in blood pressure. In fact, catecholamines often lead to an increase in blood pressure due to their vasoconstrictive effects. Therefore, decreased blood pressure is not an action of catecholamines.
16.
Blood is a:
Correct Answer
A. Suspension
Explanation
Blood is considered a suspension because it consists of various components that are not chemically bonded together. These components include red blood cells, white blood cells, platelets, and plasma. When blood is left undisturbed, these components settle down due to gravity, indicating that it is a suspension. Additionally, blood can be separated into its components through a process called centrifugation, further confirming its classification as a suspension.
17.
Together, leukocytes and platelets comprise approximately _______ % of total blood volume
Correct Answer
D. 1
Explanation
The correct answer is 1 because leukocytes and platelets make up a very small percentage of total blood volume compared to other components like red blood cells and plasma. Leukocytes, also known as white blood cells, are responsible for fighting infections and comprise only about 1% of total blood volume. Platelets, on the other hand, are responsible for blood clotting and make up an even smaller percentage of total blood volume. Therefore, the combined percentage of leukocytes and platelets is very low, closer to 1% rather than 10%, 45%, or 75%.
18.
The reflexive movement of the eyes medially when viewing close objects is called
Correct Answer
E. Convergence
Explanation
Convergence refers to the reflexive movement of the eyes medially when viewing close objects. This movement allows both eyes to focus on the same point, ensuring clear and single vision.
19.
The hormone that is antagonistic to calcitonin is:
Correct Answer
E. Parathyroid hormone
Explanation
Parathyroid hormone is the hormone that is antagonistic to calcitonin. Calcitonin is responsible for reducing the levels of calcium in the blood, while parathyroid hormone works to increase the levels of calcium. These two hormones have opposing effects on calcium regulation in the body.
20.
Olfactory cells an taste buds are normally stimulated by:
Correct Answer
D. Substances in solution
Explanation
Olfactory cells and taste buds are normally stimulated by substances in solution. This is because both the olfactory cells in the nose and the taste buds on the tongue detect and respond to different chemicals present in the substances we smell or taste. When these chemicals dissolve in a solution, they interact with the receptors in the olfactory cells and taste buds, triggering nerve signals that are then transmitted to the brain, allowing us to perceive different smells and tastes. Therefore, substances in solution play a crucial role in stimulating olfactory cells and taste buds.
21.
What is the main function of the rods in the eye?
Correct Answer
B. Vision in dim light
Explanation
The main function of the rods in the eye is to provide vision in dim light. Rods are photoreceptor cells that are highly sensitive to light and are responsible for detecting low levels of light. They are concentrated in the peripheral areas of the retina and are essential for night vision and seeing in dark environments. Rods do not distinguish colors or provide detailed vision, but they are crucial for detecting movement and shapes in low light conditions.
22.
Taste buds are not found:
Correct Answer
C. In filiform papillae
Explanation
Filiform papillae are small, cone-shaped structures on the surface of the tongue that do not contain taste buds. They are responsible for providing texture and friction to help manipulate food while eating. Unlike circumvallate and fungiform papillae, which do contain taste buds and are involved in the perception of taste, filiform papillae do not have taste receptor cells. Instead, they play a role in the mechanical aspects of eating and do not contribute to the sense of taste.
23.
Catecholamines and/or peptide hormones bind to receptors on the surface of cells that comprise target organs. This binding causes:
Correct Answer
D. Adenylate cyclase to generate cyclic AMP from ATP
Explanation
When catecholamines and/or peptide hormones bind to receptors on the surface of cells, it causes adenylate cyclase to generate cyclic AMP from ATP. Adenylate cyclase is an enzyme that catalyzes the conversion of ATP to cyclic AMP, which is a secondary messenger molecule. Cyclic AMP then activates protein kinase A, which phosphorylates target proteins and leads to various cellular responses. This signaling pathway is important for the regulation of many physiological processes, including hormone secretion, metabolism, and gene expression.
24.
_________ is a pivotal molecule associated with the external surfaces of aggregated platelets and is involved in the intrinsic and extrinsic mechanisms of blood clotting.
Correct Answer
B. PF3
Explanation
PF3, also known as platelet factor 3, is a pivotal molecule associated with the external surfaces of aggregated platelets and is involved in the intrinsic and extrinsic mechanisms of blood clotting. It plays a crucial role in the activation of prothrombin, leading to the formation of thrombin, which is essential for the clotting process. PF3 acts as a catalyst for the conversion of prothrombin to thrombin, which then promotes the conversion of fibrinogen to fibrin, forming a stable blood clot.
25.
Growth hormone:
Correct Answer
A. Promotes long bone growth during the formative years
Explanation
The growth hormone is responsible for promoting long bone growth during the formative years. This hormone plays a crucial role in stimulating the growth plates in the long bones, leading to an increase in height and overall bone development. It is not regulated by humoral mechanisms, as humoral mechanisms refer to the regulation of hormones by substances in the blood. The growth hormone is not called somatostatin, as somatostatin is a different hormone that inhibits the release of growth hormone. Secretion of growth hormone does not result in a decrease in muscle mass, but rather promotes muscle growth and development.
26.
Which organ is responsible for synthesizing ANP?
Correct Answer
A. The heart
Explanation
The correct answer is the heart. Atrial natriuretic peptide (ANP) is a hormone that is synthesized and released by the cells of the heart. It plays a crucial role in regulating blood pressure and fluid balance in the body. When the heart detects an increase in blood volume or pressure, it releases ANP, which acts to dilate blood vessels, increase urine production, and decrease sodium reabsorption in the kidneys. This helps to lower blood pressure and reduce fluid retention. Therefore, the heart is responsible for synthesizing ANP.
27.
Which of the following cannot be seen as one looks into the eye with an ophthalmoscope?
Correct Answer
D. Optic chiasma
Explanation
The optic chiasma is a structure located at the base of the brain where the optic nerves partially cross over. When looking into the eye with an ophthalmoscope, the optic chiasma cannot be directly visualized because it is situated deep within the brain. The ophthalmoscope allows visualization of the retina and its structures, such as the fovea centralis, macula lutea, and optic disk, but not the optic chiasma.
28.
Which of the following is NOT produced by the adrenal cortex:
Correct Answer
D. EpinepHrine
Explanation
Epinephrine is NOT produced by the adrenal cortex. Epinephrine, also known as adrenaline, is produced by the adrenal medulla, which is located in the center of the adrenal glands. The adrenal cortex, on the other hand, produces aldosterone, mineralocorticoids, glucocorticoids, and sex hormones. Epinephrine is a hormone that is released in response to stress or danger, and it plays a role in the body's fight-or-flight response.
29.
Sickling of red blood cells can be produced in those with sickle-cell anemia by:
Correct Answer
B. Travel at high altitude and vigorous exercise
Explanation
Sickling of red blood cells can be produced in those with sickle-cell anemia by travel at high altitude and vigorous exercise. High altitude reduces the oxygen levels in the blood, causing the red blood cells to sickle. Vigorous exercise further increases the demand for oxygen, exacerbating the sickling process. This combination of factors can lead to a higher risk of complications in individuals with sickle-cell anemia, such as pain crises and organ damage.
30.
Damage to the medial recti muscles would probably affect:
Correct Answer
D. Convergence
Explanation
Damage to the medial recti muscles would likely affect convergence. Convergence is the ability of the eyes to turn inward and focus on a nearby object. The medial recti muscles are responsible for this movement, allowing the eyes to move towards each other and maintain binocular vision. If these muscles are damaged, it would impair the ability to converge the eyes, resulting in difficulty focusing on nearby objects and potentially causing double vision.
31.
Cells that respond to peptide hormones usually do so through a sequence of biochemical reactions involving receptor and kinase activation. In order for cells to respond, it is necessary for first and second messengers to communicate. This is possible because:
Correct Answer
C. G protein acts as the link between first and second messengers
Explanation
G proteins act as the link between first and second messengers in the sequence of biochemical reactions that occur when cells respond to peptide hormones. G proteins are activated by hormone-receptor binding, and they transmit signals from the receptor to the effector enzyme or ion channel, which then produces the second messenger. This allows for the communication between the initial hormone signal and the subsequent cellular response.
32.
Accommodation is:
Correct Answer
C. Adjustment of the thickness of the lens during vision of close objects
Explanation
Accommodation refers to the adjustment of the thickness of the lens in the eye, specifically when focusing on close objects. When we look at something up close, the ciliary muscles in the eye contract, causing the lens to become thicker and rounder. This change in lens shape allows the eye to focus the incoming light rays onto the retina, resulting in clear vision of nearby objects. Therefore, the correct answer is "adjustment of the thickness of the lens during vision of close objects."
33.
Tropic hormones:
Correct Answer
D. Include ACTH and TSH
Explanation
Tropic hormones include ACTH and TSH. Tropic hormones are a type of hormone that regulate the function of other endocrine glands. They stimulate the release of hormones from these glands, which in turn affect the target cells. These hormones do not exert their effects on cells by direct gene activation. Therefore, the correct answer is that tropic hormones include ACTH and TSH, and they do not regulate the function of other endocrine glands.
34.
The major targets of growth hormone are:
Correct Answer
C. Bones and skeletal muscles
Explanation
Growth hormone primarily targets bones and skeletal muscles. It stimulates the growth and development of these tissues by promoting the synthesis of proteins and increasing the uptake of amino acids. Growth hormone also enhances the division and multiplication of cells in bones and muscles, leading to their overall growth and strengthening. Additionally, growth hormone stimulates the production of insulin-like growth factor 1 (IGF-1) in the liver, which further promotes growth and development in bones and muscles.
35.
The cells of the retina in which action potentials are generated are the:
Correct Answer
C. Ganglion cells
Explanation
The ganglion cells are responsible for generating action potentials in the cells of the retina. These cells receive input from bipolar cells, which in turn receive input from rods and cones. The ganglion cells then transmit the visual information from the retina to the brain via their axons, forming the optic nerve. Amacrine cells, on the other hand, are involved in lateral communication between different types of retinal cells, while rods and cones are responsible for detecting light and converting it into electrical signals.
36.
Visual prcessing in the thalamus does not contribute significantly to:
Correct Answer
C. Night vision
Explanation
The thalamus is a part of the brain that processes and relays sensory information to other areas. Visual processing in the thalamus primarily contributes to high-acuity vision and depth perception. It helps in perceiving fine details and judging distances. Additionally, the thalamus also plays a role in movement perception, aiding in the detection and interpretation of motion. However, it does not significantly contribute to night vision, which is mainly mediated by the specialized cells in the retina called rods. These cells are responsible for detecting low levels of light and are not heavily influenced by the thalamus.
37.
Thromboembolytic disorders:
Correct Answer
A. Include embolus formation, a clot moving within the circulatory system
Explanation
Thromboembolytic disorders involve the formation of an embolus, which is a clot that moves within the circulatory system. This means that a blood clot forms and then breaks free, traveling through the blood vessels. This can be dangerous as the clot can block blood flow to vital organs or get lodged in a smaller blood vessel, causing a blockage. Vitamin K deficiency is not a cause of thromboembolytic disorders. Uncontrolled bleeding is not a result of these disorders. Thrombus formation refers to the formation of a clot within a broken blood vessel, which is not specifically mentioned in the given description of thromboembolytic disorders.
38.
What is the average normal Ph of blood?
Correct Answer
C. 7.4
Explanation
The average normal pH of blood is 7.4. pH is a measure of the acidity or alkalinity of a solution, with a pH of 7 considered neutral. Since blood is slightly alkaline, a pH of 7.4 is within the normal range. Any significant deviation from this pH can indicate an imbalance in the body's acid-base balance and may be a sign of underlying health conditions.
39.
The type of endocrine stimulus that involves changing levels of certain blood-borne ions and nutrients is called
Correct Answer
C. Humoral stimulus
Explanation
Humoral stimulus refers to the type of endocrine stimulus that involves changing levels of certain blood-borne ions and nutrients. In this type of stimulus, the endocrine glands respond to changes in the concentration of specific substances in the blood, such as glucose or calcium. The secretion of hormones is triggered by these changes in order to maintain homeostasis and regulate bodily functions. This type of stimulus is different from neural stimulus, which involves the nervous system, and hormonal stimulus, which is regulated by other hormones. Steroid stimulus and cell-mediated stimulus are not accurate descriptions of this type of endocrine stimulus.
40.
As red blood cells age:
Correct Answer
A. Membranes "wear our" and the cells become damaged
Explanation
As red blood cells age, their membranes start to "wear out" and become damaged. This is because the membranes of the cells undergo wear and tear over time, leading to their deterioration. This process is a natural part of the aging process for red blood cells.
41.
Select the correct statement about hormonal structure or function.
Correct Answer
C. An amino acid derivative can be a hormone.
Explanation
An amino acid derivative can be a hormone because hormones can be derived from various sources, including amino acids. Examples of amino acid derivative hormones include adrenaline and thyroxine. These hormones are synthesized from specific amino acids and play important roles in regulating various physiological processes in the body.
42.
The receptor membranes of gustatory cells are:
Correct Answer
D. Gustatory hairs
Explanation
The receptor membranes of gustatory cells are called gustatory hairs. These hairs are located on the taste buds, which are specialized structures found on the tongue and other parts of the oral cavity. When food or drink comes into contact with the gustatory hairs, they send signals to the brain, allowing us to perceive different tastes such as sweet, sour, salty, and bitter.
43.
Which statement about sound localization is NOT true?
Correct Answer
D. It requires processing at the cortical level.
Explanation
Sound localization does not require processing at the cortical level. Instead, it involves the brainstem and the auditory pathway. The brainstem receives inputs from both ears and analyzes the time and intensity differences between the sounds reaching each ear. This information is then processed and integrated in the brainstem and the superior olivary complex, allowing us to localize the sound source accurately. While cortical processing may further refine and enhance sound localization, it is not a requirement for basic sound localization abilities.
44.
The most important regulator of electrolyte concentrations in extracellular fluids is:
Correct Answer
D. Aldosterone
Explanation
Aldosterone is the correct answer because it is a hormone produced by the adrenal glands that plays a crucial role in regulating electrolyte concentrations in extracellular fluids. It specifically acts on the kidneys, promoting the reabsorption of sodium ions and the excretion of potassium ions. This helps to maintain the balance of electrolytes in the body, which is essential for proper cell function, nerve transmission, and fluid balance. Cortisol, insulin, and glucagon do not have the same specific role in regulating electrolyte concentrations as aldosterone.
45.
The transparent central anterior portion of the eye through which light enters the eye is called the:
Correct Answer
A. Cornea
Explanation
The cornea is the transparent central anterior portion of the eye that allows light to enter the eye. It is responsible for refracting light and focusing it onto the retina, which then converts the light into electrical signals that can be interpreted by the brain. The cornea also plays a crucial role in protecting the eye from dust, germs, and other foreign particles.
46.
What organ in the body regulates erythrocyte production?
Correct Answer
B. Kidney
Explanation
The kidney is responsible for regulating erythrocyte production in the body. It produces a hormone called erythropoietin (EPO), which stimulates the bone marrow to produce more red blood cells. When the oxygen levels in the body are low, the kidney senses this and releases EPO, which then signals the bone marrow to increase red blood cell production. This process helps to maintain the balance of red blood cells in the body and ensure proper oxygen delivery to tissues and organs.
47.
Normal development of the immune response is due in part to hormones produced by the:
Correct Answer
D. Thymus gland
Explanation
The thymus gland is responsible for the normal development of the immune response. It produces hormones that play a crucial role in the maturation of T-cells, which are a type of white blood cell involved in immune responses. These hormones help T-cells differentiate into mature and functional cells that can effectively recognize and eliminate pathogens. Without the hormones produced by the thymus gland, the immune response may not develop properly, leading to an increased susceptibility to infections and diseases.
48.
Which of the following is a regulatory function of blood?
Correct Answer
B. Maintenance of normal pH in body tissues
Explanation
Blood plays a regulatory role in maintaining the normal pH in body tissues. It does so by buffering the acids and bases present in the body. This is important because even slight changes in pH can disrupt various physiological processes. Blood contains bicarbonate ions that can accept or donate hydrogen ions to maintain the pH within a narrow range. This regulatory function of blood ensures that the body's cells and tissues can function optimally and maintain homeostasis.
49.
Select the correct statement about olfaction.
Correct Answer
B. Some of the sensation of olfaction is actually one of pain.
Explanation
Olfaction refers to the sense of smell. The statement "Some of the sensation of olfaction is actually one of pain" is incorrect. Olfaction is not associated with pain sensation. Instead, it is the sense that allows us to detect and perceive different odors. The correct answer is that olfactory receptors have a high degree of specificity toward a single type of chemical, meaning that each receptor is specialized to detect a particular odorant molecule.
50.
Aldosterone:
Correct Answer
C. Functions to increase sodium resorption.
Explanation
Aldosterone is a hormone that plays a crucial role in regulating the balance of sodium and potassium in the body. It acts on the kidneys to increase the reabsorption of sodium, leading to an increase in sodium concentration in the blood. This helps to maintain proper fluid balance and blood pressure. Therefore, the statement "Functions to increase sodium resorption" accurately describes the role of aldosterone in the body.