which hormone initiates the preparation of the endometrium of the uterus for pregnancy

HESI A2

HESI A2 Anatomy and Physiology Practice Test

1. Which hormone initiates the preparation of the endometrium of the uterus for pregnancy?

A. FSH
B. Estrogen
C. LH
D. Progesterone

Correct answer: D

Rationale: Progesterone initiates the preparation of the endometrium of the uterus for pregnancy. It promotes the growth of blood vessels and glands in the endometrial lining, making it conducive for implantation and supporting early pregnancy. While estrogen helps in thickening the endometrium, it is progesterone that plays a crucial role in preparing it for pregnancy. FSH (Follicle-stimulating hormone) is involved in stimulating ovarian follicles, not directly in preparing the endometrium. LH (Luteinizing hormone) triggers ovulation but does not primarily prepare the endometrium for pregnancy.

2. Which is another name for thiamine?

A. Vitamin B1
B. Vitamin B2
C. Vitamin B6
D. Vitamin D

Correct answer: A

Rationale: Thiamine is another name for Vitamin B1. It is an essential vitamin that plays a crucial role in energy metabolism and is important for the proper functioning of the nervous system. Vitamin B2 is riboflavin, not thiamine. Vitamin B6 is pyridoxine, not thiamine. Vitamin D is a different vitamin responsible for calcium absorption and bone health, not thiamine. Therefore, the correct answer is Vitamin B1.

3. Which structure in the brain regulates sleep and wakefulness?

A. Hypothalamus
B. Thalamus
C. Pineal gland
D. Cerebellum

Correct answer: C

Rationale: The pineal gland, located in the brain, is responsible for regulating sleep and wakefulness by secreting the hormone melatonin. Melatonin plays a crucial role in controlling the sleep-wake cycle, with higher levels at night inducing sleepiness. The hypothalamus (Choice A) regulates various physiological processes but is not primarily responsible for sleep-wake cycles. The thalamus (Choice B) is involved in relaying sensory information but not specifically in regulating sleep. The cerebellum (Choice D) plays a role in coordination and motor control rather than sleep regulation.

4. Which type of muscle is found in the walls of hollow organs?

A. Skeletal muscle
B. Cardiac muscle
C. Smooth muscle
D. Striated muscle

Correct answer: C

Rationale: Smooth muscle tissue is found in the walls of hollow organs, such as the intestines, blood vessels, and bladder. It contracts involuntarily, allowing for movements like peristalsis in the intestines and regulation of blood flow in blood vessels. Skeletal muscle (Choice A) is attached to bones and helps in voluntary movements. Cardiac muscle (Choice B) is found in the heart and contracts involuntarily to pump blood. Striated muscle (Choice D) refers to both skeletal and cardiac muscles, which have a striped appearance due to the organization of their filaments. However, smooth muscle (Choice C) is specifically the type found in hollow organs.

5. What type of joint is found at the elbow?

A. Ball and socket
B. Hinge
C. Pivot
D. Saddle

Correct answer: B

Rationale: The correct answer is B: Hinge. A hinge joint, such as the one found at the elbow, allows for movement primarily in one plane, enabling flexion and extension similar to the movement of a door hinge. This joint structure permits bending and straightening of the arm, controlling the range of motion in a specific direction. Choices A, C, and D are incorrect. A ball and socket joint allows for multi-axial movement like the hip joint, a pivot joint allows for rotation around an axis like the joint between the first and second cervical vertebrae, and a saddle joint allows for movement in two planes at right angles to each other like the joint at the base of the thumb.