Connective tissue fibers include:

Correct Answer: C

Rationale: The correct answer is C: Reticular, elastic, and collagen fibers. Reticular fibers provide structural support, elastic fibers allow flexibility, and collagen fibers offer strength to connective tissues. Purkinje fibers are specialized cardiac muscle fibers, not connective tissue fibers. Choice A is incorrect because it includes Purkinje fibers, which are not part of connective tissue. Choice B is incorrect as it includes Purkinje fibers instead of reticular fibers. Choice D is incorrect because it lacks elastic fibers, which are essential for tissue flexibility. Therefore, choice C is the correct answer as it includes all three types of essential connective tissue fibers.

Correct Answer: A

Rationale: The correct answer is A: Secretory phase. During the secretory phase of the menstrual cycle, the endometrial thickness is greatest due to increased progesterone levels, leading to thickening of the endometrium in preparation for potential implantation of a fertilized egg. This phase occurs after ovulation and is characterized by glandular secretions and increased vascularity to support a potential pregnancy. Summary: - Menstrual phase (B) is incorrect as it is characterized by shedding of the endometrial lining. - Proliferative phase (C) is incorrect as it involves endometrial thickening but not to the extent seen in the secretory phase. - Late follicular phase (D) is incorrect as it precedes ovulation and is primarily characterized by follicular development rather than significant endometrial thickening.

Correct Answer: C

Rationale: The correct answer is C: 7. The cervical spine consists of 7 vertebrae, labeled as C1 to C7. Each vertebra plays a vital role in supporting the head and facilitating neck movement. C1 is known as the atlas, C2 is the axis, and C3 to C7 are structurally similar cervical vertebrae. These vertebrae house the spinal cord and provide flexibility for head movements. Choices A, B, and D are incorrect because the cervical spine does not have 2, 5, or 8 vertebrae. It is crucial to understand the anatomical structure of the spine to determine the correct number of cervical vertebrae.

Correct Answer: A

Rationale: The correct answer is A: Corpus callosum. The corpus callosum is the main commissural fiber in the brain that connects the two cerebral hemispheres, allowing for communication and coordination between them. It is the largest and most prominent commissural fiber in the brain, making it the correct choice. Summary of why other choices are incorrect: B: Anterior commissure - Connects certain regions of the cerebral hemispheres, but not as prominent or as large as the corpus callosum. C: Posterior commissure - Connects certain structures in the brainstem, not the cerebral hemispheres. D: Hippocampal commissure - Connects the two hippocampi, not the cerebral hemispheres.

Correct Answer: C

Rationale: The correct answer is C: Stenosis of aqueduct of Sylvia. This condition causes obstruction in the Sylvian aqueduct, leading to hydrocephalus with enlarged lateral and third ventricles but a normal fourth ventricle. Holoprosencephaly (A) is a midline defect, not specific to ventricle enlargement. Disorder of prosencephalon (B) is too broad and doesn't specifically address ventricle enlargement. Meningitis with blockage of arachnoid villi (D) is typically associated with communicating hydrocephalus, not specific to the aqueductal stenosis pattern seen in this case.