Anatomy and Physiology Flashcards

The pelvic floor is primarily composed of which muscle group?

Answer: Levator ani and coccygeus muscles

The pelvic diaphragm consists of the levator ani (pubococcygeus, puborectalis, iliococcygeus) and coccygeus muscles, which support the pelvic viscera.

Which pelvic diameter is the most clinically critical for assessing safe vaginal delivery?

Answer: Obstetric conjugate

The obstetric conjugate (from the inner surface of the pubic symphysis to the sacral promontory) is the shortest AP diameter of the pelvic inlet and is the critical measurement for engagement of the fetal head.

Which hormone is responsible for the milk ejection (let-down) reflex during breastfeeding?

Answer: Oxytocin

Oxytocin, released from the posterior pituitary in response to nipple stimulation, causes contraction of myoepithelial cells around alveoli, ejecting milk into the ducts.

In the cardinal movements of labor, which sequence correctly describes the progression?

Answer: Engagement, descent, flexion, internal rotation, extension, external rotation, expulsion

The seven cardinal movements are: engagement, descent, flexion, internal rotation, extension, external rotation (restitution), and expulsion — occurring as the fetal head negotiates the birth canal.

Fetal station is measured relative to which pelvic landmark?

Answer: Ischial spines

Station describes the relationship of the fetal presenting part to the ischial spines; station 0 means the presenting part is at the level of the spines, with negative values above and positive values below.

Cooper's suspensory ligaments are fibrous structures found within which anatomical structure?

Answer: Breast

Cooper's ligaments are fibrous bands that extend from the breast skin to the underlying pectoral fascia, providing structural support to breast tissue; their distortion can cause skin dimpling in malignancy.

Which hormone primarily stimulates milk production (lactogenesis) in the postpartum period?

Answer: Prolactin

Prolactin, secreted by the anterior pituitary, drives alveolar cell milk synthesis; the postpartum drop in estrogen and progesterone removes their inhibitory effect, allowing prolactin to act.