The penis consists of three parallel erectile tissues. Which of the following occurs as a pair?

• A. Corpora cavernosa
• B. Glans penis
• C. Tunica albuginea
• D. Corpus spongiosum

Answer: (A)

Verified step by step guidance

1. Step 1: Begin by identifying the anatomical structures listed in the problem: Corpora cavernosa, Glans penis, Tunica albuginea, and Corpus spongiosum. Understand their roles and locations within the penis.
2. Step 2: Recall that the penis contains three parallel erectile tissues: two corpora cavernosa and one corpus spongiosum. These tissues are responsible for engorgement during erection.
3. Step 3: Focus on the term 'occurs as a pair.' This indicates that the structure being referred to must exist in two identical units within the penis.
4. Step 4: Analyze the options: The corpora cavernosa are paired structures located on the dorsal side of the penis, while the corpus spongiosum is a single structure surrounding the urethra. The glans penis is the expanded distal end of the corpus spongiosum, and the tunica albuginea is a connective tissue layer surrounding the erectile tissues.
5. Step 5: Conclude that the corpora cavernosa are the correct answer because they are the only structure listed that occurs as a pair in the penis.