Anatomy and Physiology of the Reproductive System

The reproductive system is a collection of organs that work together for the purpose of producing a new life. The major organs of the reproductive system include the external genitalia and internal organs. The anatomy of male and female reproductive system is different. The male reproductive system includes the scrotum, testicles, spermatic ducts, sex glands and penis. The female reproductive anatomy includes vagina, uterus, ovaries, and fallopian tubes.

Reproductive physical maturity and the capacity for human reproduction begin during puberty. During puberty, the hypothalamus produces hormones, which stimulate the gonads to produce testosterone (males) and estrogen and progesterone (females).

Male puberty generally occurs between the ages of 13-15 and is characterized by the secretion of the male hormone testosterone, which stimulates spermatogenesis, and the development of secondary sexual characteristics (increased height and weight, broadening shoulders, voice deepening, and muscle development).

Female puberty generally occurs between the ages of 9-13, and results in ovulation and menstruation, which involve cyclic hormonal changes in estrogen and progesterone. Secondary sexual characteristics (breast enlargement, widening hips, increased height, weight and fat distribution) also occur as part of the female pubertal process.

Function of the reproductive system is reproduction. Fertilization is the first step in pregnancy. During coitus (sexual intercourse) between a male and a female, semen is released into the vagina and transported through the uterus into the fallopian tube. Fertilization can only occur if intercourse takes place before the time of ovulation that usually occurs “mid-cycle”, or about 14 days before the woman's next menstrual period. At the time of ovulation, the ovum is released from the ovary and transported in the fallopian tube where it remains for about 24-48 hours. Pregnancy is most likely to occur if fresh semen is present when ovulation occurs.

Sperm cells remain viable within the female reproductive tract for about 72 hours. During fertilization, the sperm enters the cell membrane of the ovum so the nuclei of the sperm and egg cells combine to form a zygote. The zygote will remain in the fallopian tube for approximately three days before it travels to the uterus where it will remain for approximately four to five days before implantation into the uterine lining.

 

1. Answer the questions:

1. What is the reproductive system?

2. What does the word puberty mean?

3. What does the hypothalamus regulate?

4. When does male puberty occur?

5. When does female puberty occur?

6. When can fertilization occur?

7. How long do sperm cells remain viable in the reproductive tract?

8. What is zygote?

 

2. Match the terms with the definitions:

1. puberty 2. testosterone 3. estrogen 4. progesterone 5. fertilization 7. gonads

a) A white crystalline steroid hormone produced primarily in the testes and responsible for the development and maintenance of male secondary sex characteristics. b) A steroid hormone, secreted by the corpus luteum of the ovary and by the placenta, that acts to prepare the uterus for implantation of the fertilized ovum, to maintain pregnancy, and to promote development of the mammary glands. c) The act or process of initiating biological reproduction by insemination or pollination. d) The stage of adolescence in which an individual becomes physiologically capable of sexual reproduction. e) Any of several steroid hormones produced chiefly by the ovaries and responsible for promoting estrus and the development and maintenance of female secondary sex characteristics. f) Any organ or gland in which gametes are produced; an ovary or testis.

Text 5

Read and translate the text:

The Endocrine Glands

All glands in the human body can be divided into glands with ducts and ductless. Ductless glands have no duct but they make a secretion which they pour into the blood stream. These secretions are called internal secretions or hormones, and glands which produce them are also called endocrine glands.

The chief ductless glands are: the thyroid gland, the adrenal glands and the pituitary gland.

There are also other important glands which produce internal secretions as well as other substances, e.g. the pancreas, the liver and the reproductive glands.

The thyroid gland lies in the front of the neck. It consists of two lobes lying on either side, joined by a narrow band which crosses the trachea immediately below the larynx. The gland is well supplied with blood vessels and consists essentially of secreting cells. The cells secrete thyroxin, which passes into the circulation. Thyroxin controls the general metabolism or activity of the body tissues.

The adrenal glands are two small triangular glands lying one over each kidney. They consist of two parts, cortex and medulla. The outer part produces a secretion which affects sex. Oversecretion produces masculinity in the female and in the male it produces too early development of the male reproductive organs.

The medulla produces a very important secretion called adrenalin, It secreted amount increases in excitement and strong emotions such as fear or anger. The adrenals are therefore sometimes called the glands of “flight and fight”.

The pituitary gland (hypophysis) is a small gland about the size of a pea and yet is of great importance. It lies in the pituitary fossa in the base of the skull. It consists of an anterior and a posterior lobe.

The anterior lobe is the larger and produces a number of important hormones affecting growth and sexual development and the functioning of the ductless glands, particularly the thyroid and the adrenal glands. Undersecretion of this lobe in childhood causes dwarfing. Oversecretion causes overgrowth or gigantism. In the adult this oversecretion causes overgrowth of the head, hands, and feet, particularly affecting the lower jaw. This condition is known as acromegaly.

The posterior lobe produces the secretion known as pituitrin. This stimulates involuntary muscle and therefore contracts the blood vessels and raises blood pressure, stimulates peristalsis, contracts the uterus; it affects the use of water by the body.

 

1. Answer the questions:

1. How are glands in the human body classified?

2. What is hormone?

3. What are the main ductless glands?

4. What is the structure of the thyroid gland?

5. What does thyroxin control?

6. What is the structure of the adrenal glands?

7. When is adrenalin secreted?

8. What is the structure of the pituitary gland?

9. What does the pituitary gland affect?

 

2. Open the brackets using the correct form of the verb. Translate the sentences:

1. Thyroxin (to control) the general metabolism or activity of the body tissues.

2. The anterior lobe of the hypothesis (to produce) a number of important hormones.

3. The thyroid gland (to supply) well with blood vessels.

4. The hormones (to deliver) to various organs.

5. The chemical composition of some hormones (to be) well-known.

6. Each gland (to consist) of glandular epithelial tissue.

7. The outer part of the adrenal glands (to produce) a secretion which affects sex.

8. The hormones (to affect) the functions of the different parts of the nervous system.