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# 13.58: Male Reproductive Structures

Difficulty Level: At Grade Created by: CK-12
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Practice Male Reproductive Structures
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Would you believe the male reproductive structures are over 100 feet long?

The male reproductive system has two goals: to produce and deliver sperm and to secrete testosterone. Might seem simple. But there are a number of complicated processes and structures - including over 100 feet of tubules - that go into these simple goals.

### Male Reproductive Structures

The reproductive system in both males and females consists of structures that produce reproductive cells, or gametes, and secrete sex hormones. A gamete is a haploid cell that combines with another haploid gamete during fertilization. Sex hormones are chemical messengers that control sexual development and reproduction. The male reproductive system consists of structures that produce male gametes called sperm and secrete the male sex hormone testosterone.

The main structures of the male reproductive system are shown in Figure below . Locate them in the figure as you read about them below. You can also watch an animation about male reproductive structures at this link: http://www.medindia.net/animation/male_reproductive_system.asp .

Male Reproductive Structures. Organs of the male reproductive system include the penis, testes, and epididymis. Several ducts and glands are also part of the system. Do you know the reproductive functions of any of these structures?

#### Penis

The penis is an external genital organ with a long shaft and enlarged tip called the glans penis. The shaft of the penis contains erectile tissues that can fill with blood and cause an erection. When this occurs, the penis gets bigger and stiffer. The urethra passes through the penis. Sperm pass out of the body through the urethra. (During urination, the urethra carries urine from the bladder.)

#### Testes

The two testes (singular, testis) are located below the penis. They hang between the thighs in a sac of skin called the scrotum . Each testis contains more than 30 meters (90 feet) of tiny, tightly packed tubules called seminiferous tubules . These tubules are the functional units of the testes. They produce sperm and secrete testosterone .

#### Epididymis

The seminiferous tubules within each testis join to form the epididymis. The epididymis (plural, epididymes) is a coiled tube about 6 meters (20 feet) long lying atop the testis inside the scrotum. The functions of the epididymis are to mature and store sperm until they leave the body.

#### Ducts and Glands

In addition to these organs, the male reproductive system consists of a series of ducts and glands. Ducts include the vas deferens and ejaculatory ducts. They transport sperm from the epididymes to the urethra in the penis. Glands include the seminal vesicles and prostate gland . They secrete substances that become part of semen.

#### Semen

Semen is the fluid that carries sperm through the urethra and out of the body. In addition to sperm, it contains secretions from the glands. The secretions control pH and provide sperm with nutrients for energy.

### Summary

• The male reproductive system consists of structures that produce sperm and secrete testosterone.
• Male reproductive structures include the penis, testes, and epididymes.

### Practice I

Use this resource to answer the questions that follow.

• http://www.hippocampus.org/Biology $\rightarrow$ Biology for AP* $\rightarrow$ Search: Reproductive Anatomy
1. What is the role of the reproductive system?
2. Why are the testes outside the body?
3. Describe the route of sperm through the reproductive system.
4. What comprises semen?
5. Describe the role of the prostate gland.

### Review

1. What are the two major roles of the male reproductive system?

2. Name two male reproductive organs and identify their functions.

### Vocabulary Language: English Spanish

epididymis

epididymis

(plural, epididymes): One of two male reproductive organs where sperm mature and are stored until they leave the body.
penis

penis

Male reproductive organ containing the urethra, through which sperm and urine pass out of the body.
prostate gland

prostate gland

Gland that secretes substances that become part of semen.
reproductive system

reproductive system

System of organs that produces gametes and secretes sex hormones.
scrotum

scrotum

Sac of skin that holds the testes.
semen

semen

Fluid containing sperm and gland secretions that nourish sperm and carry them through the urethra and out of the body.
seminal vesicles

seminal vesicles

Gland that secretes substances that become part of semen.
seminiferous tubules

seminiferous tubules

The functional units of the testes.
testis

testis

(plural, testes): Male reproductive organ that produces sperm and secretes testosterone.
testosterone

testosterone

Male sex hormone secreted by the testes.
vas deferens

vas deferens

Tubes that transport sperm from the epididymis in anticipation of ejaculation.

## Date Created:

Feb 24, 2012

Nov 02, 2015
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