Problem 2 - Campbell Biology

Question

Knowledge/Comprehension In male mammals, excretory and reproductive systems share (A) the vas deferens. \(\quad\) (C) the seminal vesicle. (B) the urethra. \(\quad\) (D) the prostate.

Step-by-Step Solution

Answer

B. the urethra.

Step 1: Understand the Systems Involved

First, identify the two systems mentioned: the excretory system, which removes waste from the body, and the reproductive system, which is responsible for reproduction.

Step 2: Identify the Shared Structures

Determine which structures are part of both the excretory and reproductive systems in male mammals. These structures will facilitate both waste excretion and the transport of reproductive cells or fluids.

Step 3: Analyze Each Option

Review each option to see which ones are involved in both systems: A. The vas deferens – a part of the reproductive system that transports sperm.B. The urethra – a tube that carries urine from the bladder and also conducts semen.C. The seminal vesicle – a gland that adds fluid to semen.D. The prostate – a gland that also adds fluids to semen.

Step 4: Determine the Correct Answer

Since the urethra is the only structure that functions in both the excretory system (carrying urine) and the reproductive system (conducting semen), the correct answer is B.

Key Concepts

Excretory System

The excretory system is vital for removing waste products from the body. This system includes kidneys, ureters, the bladder, and the urethra.

Key functions are:

• Filtering waste and excess substances from the bloodstream via the kidneys.
• Transporting urine from the kidneys to the bladder through the ureters.
• Storing urine in the bladder until it is ready for excretion.
• Excreting urine through the urethra.

The main objective is to maintain the body's internal environment, ensuring it stays balanced by removing potentially harmful waste products.

Reproductive System

In male mammals, the reproductive system plays a crucial role in producing and transporting reproductive cells (sperm). This system includes the testes, vas deferens, seminal vesicles, prostate gland, and urethra.

Key functions include:

• Producing sperm in the testes.
• Transporting sperm via the vas deferens.
• Adding fluid to sperm via seminal vesicles to form semen.
• Adding additional fluids through the prostate gland.
• Conducting semen out of the body through the urethra during ejaculation.

These processes ensure that the sperm can successfully reach and fertilize an egg, leading to reproduction.

Urethra

In male mammals, the urethra is a shared structure between the excretory and reproductive systems.

Functions it serves are:

• Carrying urine from the bladder to the outside of the body.
• Conducting semen during ejaculation.

This dual-function aspect is unique and critical. It means that the urethra must seamlessly switch between roles depending on whether it is excreting waste (urine) or transporting reproductive fluids (semen).