Medical education diagram: Menstrual Cycle - a clean horizontal timeline showing a 28-day cycle with two main phases labeled: Follicular Phase (Days 1-14, proliferative) and Luteal Phase (Days 14-28, secretory). Include hormone curves for FSH, LH, Estrogen (Estradiol), and Progesterone. Mark Day 14 ovulation with an upward arrow. Show endometrial changes beneath: Menstruation (Days 1-5), Proliferative phase growth, then Secretory phase. Below that, show ovarian events: primordial follicle → growing follicle → Graafian follicle → Ovulation → Corpus Luteum → Corpus albicans. Clean, colorful, labeled arrows and curves on white background.

Medical education flowchart: Spermatogenesis - step-by-step vertical flow showing: Spermatogonium (2n) → [Mitosis] → Primary Spermatocyte (2n) → [Meiosis I] → Two Secondary Spermatocytes (n) → [Meiosis II] → Four Spermatids (n) → [Spermiogenesis] → Four Mature Spermatozoa. Each step in a labeled box with arrows. Alongside show Spermiogenesis detail: acrosome cap formation from Golgi, tail (flagellum) development from centrioles, mitochondrial sheath formation, loss of residual cytoplasm. Show Sertoli cell support and Leydig cell testosterone influence with labeled arrows. Clean blue and purple color scheme, medical textbook style.

Medical education flowchart: Hypothalamo-Pituitary-Ovarian Axis - vertical cascade diagram. Top box: Hypothalamus secretes GnRH (pulsatile). Arrow down to: Anterior Pituitary secretes FSH and LH. Arrow down to: Ovary showing follicle development and corpus luteum. Ovary produces Estrogen and Progesterone. Show negative feedback loops with dashed arrows returning up: low estrogen = negative feedback on both; high estrogen (preovulatory) = positive feedback causing LH surge triggering ovulation. Label each hormone, each organ, and each feedback loop clearly. Show that FSH stimulates follicle growth and LH triggers ovulation and luteinization. Clean diagram on white background, blue and pink color scheme.