Problem 8 - Biology of Humans: Concepts, Applications, and Issues

Question

Which of the following is the correct pairing of a structure with its function? a. endometrium: the usual site of fertilization b. corpus luteum: production of estrogen and progesterone c. epididymis: production of testosterone d. seminal vesicles: storage of sperm while they mature

Step-by-Step Solution

Answer

b. corpus luteum: production of estrogen and progesterone

Step 1 - Understand the question

Identify the biological structures and the functions listed for each option.

Step 2 - Analyze option a

Option a states 'endometrium: the usual site of fertilization.' The endometrium is the inner lining of the uterus where a fertilized egg implants and develops during pregnancy. Fertilization usually occurs in the fallopian tubes, not the endometrium.

Step 3 - Analyze option b

Option b states 'corpus luteum: production of estrogen and progesterone.' The corpus luteum is a temporary endocrine structure in female ovaries and is indeed responsible for the production of estrogen and progesterone.

Step 4 - Analyze option c

Option c states 'epididymis: production of testosterone.' The epididymis is actually responsible for the storage and maturation of sperm, not the production of testosterone.

Step 5 - Analyze option d

Option d states 'seminal vesicles: storage of sperm while they mature.' The seminal vesicles produce seminal fluid, but they do not store sperm.

Step 6 - Determine the correct pairing

Compare the explanations for each option to decide which one correctly pairs the structure with its function.

Key Concepts

endometrium

The endometrium is the inner lining of the uterus. Its primary role is to support pregnancy. During the menstrual cycle, it thickens in response to hormonal changes. If fertilization of an egg occurs, the fertilized egg will implant into the endometrium for nourishment and development. Typically, fertilization occurs in the fallopian tubes, not in the endometrium. The abundant blood supply of the endometrium is crucial as it provides nutrients and oxygen to the developing embryo. When pregnancy does not occur, the endometrium breaks down and is shed during menstruation.

• location: inner lining of the uterus
• function: supports embryo implantation and development
• relation to menstruation: sheds if no pregnancy

corpus luteum

The corpus luteum forms in the ovary after an egg is released during ovulation. It is a temporary endocrine structure. Its primary function is to produce the hormones estrogen and progesterone. These hormones are crucial for regulating the menstrual cycle and sustaining early pregnancy. Progesterone, in particular, helps maintain the uterine lining for potential embryo implantation. If pregnancy does not occur, the corpus luteum breaks down, leading to a drop in hormone levels and the onset of menstruation.

• formation: post-ovulation in the ovary
• primary hormones: estrogen and progesterone
• duration: temporary structure

epididymis

The epididymis is a long, coiled tube located at the back of the testes. It is the site where sperm mature and are stored. Unlike the corpus luteum, the epididymis does not produce hormones. Instead, it provides an environment for sperm to gain motility and the ability to fertilize an egg. The journey of sperm through the epididymis can take several days. Once matured, sperm are stored in the tail of the epididymis until ejaculation.

• location: behind the testes
• function: sperm maturation and storage
• hormone production: none

seminal vesicles

The seminal vesicles are two glands located behind the bladder, near the base of the penis. They do not store sperm; instead, they produce seminal fluid, which makes up a significant portion of semen. This fluid contains nutrients like fructose, which provide energy for sperm, and substances that help in the mobility and survival of sperm within the female reproductive tract. When a man ejaculates, the seminal fluid from the seminal vesicles mixes with sperm from the epididymis, forming the semen that is expelled.

• location: behind the bladder
• function: produce seminal fluid
• contribution to ejaculation: mixes with sperm to form semen