A nurse is teaching an anatomy class about the external male genitalia. Which of the following are components of the penis? Select all that apply

Reproductive system function involves the generation and support of gametes, secretion of essential hormones, and coordination of structures for fertilization. The system includes gonads, ducts, accessory glands, and external genitalia, all of which coordinate to ensure gamete production, transport, and hormonal regulation. Major hormones such as testosterone in males (normal range: 300–1,000 ng/dL) and estrogen in females (estradiol normal range: 30–400 pg/mL, depending on phase) regulate secondary sexual characteristics, libido, and reproductive organ development.

Rationale for correct answers

B. The reproductive system's primary role includes the production of gametes: spermatozoa in males and ova in females. This function is performed by the testes and ovaries, respectively, through spermatogenesis and oogenesis.

C. Gametes must be transported and stored effectively to allow for fertilization. In males, sperm are transported through the vas deferens and stored temporarily in the epididymis. In females, ova travel via the fallopian tubes where fertilization occurs.

E. The reproductive system produces sex hormones such as testosterone, estrogen, and progesterone, which are essential for the development of secondary sexual characteristics like facial hair, breast development, voice changes, and body fat distribution.

Rationale for incorrect answers

A. Regulation of blood pressure is primarily governed by the renin-angiotensin-aldosterone system (RAAS), autonomic nervous system, and kidneys, not the reproductive system. While reproductive hormones can influence vascular tone indirectly, they are not central to blood pressure homeostasis.

D. Regulation of body temperature is the function of the hypothalamus in the brain, using mechanisms such as sweating, vasodilation, and shivering. The reproductive system is not directly responsible for thermoregulation, though testes rely on cooler temperatures (~2–4°C below body temp) for spermatogenesis.

Take home points

• The reproductive system produces, stores, and transports gametes.
• Sex hormones regulate secondary sexual features and reproductive organ development.
• The hypothalamus and kidneys control body temperature and blood pressure, not reproductive structures.
• Gametogenesis occurs in gonads—testes in males and ovaries in females.

Penile anatomy includes specialized erectile tissues, vascular structures, and sensory regions that function in urination, copulation, and ejaculation. The penis is composed of two corpora cavernosa and one corpus spongiosum, all enveloped in dense connective tissue. The glans penis, an extension of the corpus spongiosum, houses numerous sensory receptors. Normal penile erection involves vasodilation and blood filling of erectile tissues, with typical penile length in erect state ranging from 1B.9 to 1E.5 cm and penile arterial systolic velocity >30 cm/s indicating normal erectile function.

Rationale for correct answers

A. The corpora cavernosa are paired cylindrical erectile tissues located dorsolaterally in the penis. They are primarily responsible for penile rigidity during erection by engorging with blood via deep penile arteries.

C. The glans penis is the bulbous distal end of the penis, formed by the expansion of the corpus spongiosum. It is richly innervated and plays a key role in tactile sensation and sexual stimulation.

E. The corpus spongiosum is a single midline erectile structure surrounding the urethra. It prevents urethral compression during erection and expands distally to form the glans penis, contributing to both structure and function.

Rationale for incorrect answers

B. The rete testis is not a penile structure. It is a network of interconnecting tubules located in the mediastinum testis, responsible for collecting sperm from seminiferous tubules and transporting it to the epididymis. It has no structural or functional association with the penis.

D. The corpus luteum is a temporary endocrine structure formed from the ruptured ovarian follicle after ovulation in females. It secretes progesterone and estrogen. It is exclusive to the female reproductive system and unrelated to male genital anatomy.

Take home points

• The penis consists of corpora cavernosa, corpus spongiosum, and glans penis.
• Rete testis is located within the testes, not the penis.
• Corpus luteum is a female ovarian structure, not present in males.
• Erectile tissues are essential for penile rigidity and reproductive function.