the hypothalamus a part of the brain plays a crucial role in endocrine regulation it secretes gnrh gonadotropin releasing hormone which stimulates the

ATI TEAS 7

TEAS Test 7 science

1. The hypothalamus, a part of the brain, plays a crucial role in endocrine regulation. It secretes GnRH (Gonadotropin-releasing hormone) which stimulates the pituitary gland to produce FSH and LH. What is the MAIN function of FSH and LH?

A. Regulate blood sugar levels
B. Control growth and development
C. Stimulate the fight-or-flight response
D. Maintain calcium homeostasis

Correct answer: B

Rationale: FSH (Follicle-stimulating hormone) and LH (Luteinizing hormone) are hormones produced by the pituitary gland in response to GnRH from the hypothalamus. FSH plays a key role in the growth and development of ovarian follicles in females and sperm production in males. LH is essential for the maturation of the ovarian follicle, ovulation, and the formation of the corpus luteum in females, as well as the production of testosterone in males. Therefore, the main function of FSH and LH is to control growth and development in the reproductive system. Choices A, C, and D are incorrect as they do not align with the roles of FSH and LH in reproductive physiology. Regulating blood sugar levels is primarily the function of insulin and glucagon, controlling the fight-or-flight response involves hormones like adrenaline and noradrenaline, and maintaining calcium homeostasis is mainly regulated by parathyroid hormone and calcitonin.

2. What is the largest bone in the human body?

A. Femur (thigh bone)
B. Tibia (shin bone)
C. Humerus (upper arm bone)
D. Scapula (shoulder blade)

Correct answer: A

Rationale: The femur, also known as the thigh bone, holds the title of the largest bone in the human body. Situated in the upper leg, the femur plays a vital role in supporting the body's weight and enabling movement. While the tibia (shin bone), humerus (upper arm bone), and scapula (shoulder blade) are all essential bones, none of them match the femur in terms of size and importance. The tibia, humerus, and scapula are comparatively smaller bones with specific functions in their respective areas of the body, but they do not surpass the femur in size or significance.

3. Which radioactive isotope is commonly used in medical imaging techniques such as PET scans?

A. Uranium-235
B. Plutonium-239
C. Potassium-40
D. Fluorine-18

Correct answer: D

Rationale: Fluorine-18 is the radioactive isotope commonly used in medical imaging techniques such as PET scans. It is frequently used in the form of fluorodeoxyglucose (FDG) to locate areas of heightened metabolic activity in the body, such as in cancer cells. Uranium-235 and Plutonium-239 are not typically employed in medical imaging, and Potassium-40, while a naturally occurring radioactive isotope found in the human body, is not commonly used in medical imaging techniques.

4. Which part of the heart is responsible for generating the QRS complex on an ECG?

A. Sinoatrial node (SA node)
B. Atrioventricular node (AV node)
C. Bundle of His
D. Ventricular muscle cells

Correct answer: D

Rationale: The QRS complex on an ECG represents ventricular depolarization. This electrical activity is generated by the ventricular muscle cells. While the SA node generates the P wave, the AV node delays the impulse, and the Bundle of His and Purkinje fibers assist in rapidly conducting the impulse through the ventricles, it is the ventricular muscle cells that specifically create the QRS complex. Therefore, choice D, Ventricular muscle cells, is the correct answer. Choices A, B, and C are incorrect as they are primarily involved in initiating and coordinating the electrical impulses in the heart but do not directly generate the QRS complex on an ECG.

5. In a scientific investigation, what is the first step?

A. Analysis of results
B. Drawing conclusions
C. Formation of hypothesis
D. Performing the experiment

Correct answer: C

Rationale: The correct answer is C: Formation of hypothesis. In a scientific investigation, forming a hypothesis is the initial step. A hypothesis is an educated guess or prediction based on existing knowledge and observations. It helps guide the experiment and provides a direction for the research process. Without a hypothesis, there is no specific aim or goal for the experiment. Choices A, B, and D are incorrect because they occur after the formation of a hypothesis. Analysis of results and drawing conclusions typically come after the experiment has been conducted, while performing the experiment is done to test the hypothesis formed at the beginning of the investigation.