Module 2 Section 1

Question 1

explain the reproductive system

Answer 1

• successful sexual reproduction depends on the union of male and female gametes in order to form a new individual with a full set of chromosomes
• male and female reproductive systems are dramatically different but have the common purpose of producing gametes and are designed for allowing the union of female and male gametes

Question 2

what are the primary reproductive organs

Answer 2

• gonads
• testes in males and ovaries in females
• male and female reproductive system include a reproductive tract allowing for the transport of gametes after they are produced as well as many accessory sex glands that release supportive secretions into the reproductive tract

Question 3

Name each structure

Answer 3

Question 4

what are the two essential reproductive functions in males

Answer 4

1. the production of sperm
2. the delivery of sperm to the female

Question 5

explain the production of sperm

Answer 5

• sperm are the gamete cells of the male reproductive system and are produced in the testes
• the testes are found outside the abdominal cavity suspended in the scrotum

Question 6

explain the delivery of sperm to the female

Answer 6

• sperm exit the testes through the male reproductive tract and are suspended in secretions from the accessory sex glands: the seminal vesicles, the prostate gland, and the bulbourethral glands
• these secretions are critical for sperm viability and for the delivery of the sperm to the female reproductive system via the penis

Question 7

name each structure

Answer 7

Question 8

what are the 6 essential functions of female reproduction

Answer 8

1. the production of ova
2. reception of sperm
3. transport of ovum and sperm to a common site for fertilization
4. maintenance of the developing fetus
5. birth of the baby
6. nourishing the baby by milk production

Question 9

explain the production of ova

Answer 9

ova or eggs are produced in the ovaries and individual ova undergo cyclical maturation

Question 10

explain the reception of sperm

Answer 10

the reception of sperm occurs in the vagina, which is a muscular tube that connects the uterus, via the cervical canal, to the external environment

Question 11

explain the transport of ovum and sperm to a common site for fertilization

Answer 11

the ova leave the ovaries and move into the Fallopian tubes, where they can be fertilized by sperm that have traveled from the vagina, through the cervical canal, into the uterus, and ultimately into the Fallopian tubes

Question 12

explain the maintenance of the developing fetus

Answer 12

this occurs within the uterus for about nine months during pregnancy

Question 13

explain the birth of the baby

Answer 13

referred to as parturition

Question 14

explain nourishing the baby through milk production

Answer 14

referred to as lactation

Question 15

what is sexual differentiation

Answer 15

• refers to the embryonic development of both the external genitalia and the reproductive tract
• this process occurs due to the differences between males and females at 3 levels
  1. genetic
  2. gonadal
  3. phenotypic

Question 16

explain sexual differentiation - genetic

Answer 16

• genetic sex is determined by the combination of sex chromosomes at conception
• the gametes are produced via meiosis, in which diploid parent cells divide to produce haploid gamete cells (sperm and ova)
• half the sperm produced cary an X chromosome, while the other half have a Y chromosome
• all ova have X chromosome

Question 17

what happens when 2 haploid cells combine

Answer 17

• they create a fertilized ovum with 2 sets of 23 chromosomes, or 46 total
• if a sperm carrying an X chromosome fertilizes an ovum, then the genetic sex of the developing embryo is XX (female)
• if a sperm carrying a Y chromosome fertilizes an ovum, then the embryos genetic sex is XY (male)

Question 18

explain sexual differentiation - gonadal

Answer 18

• gonadal sex is determined by the presence or absence of a Y chromosome
• for the first 6 weeks of gestation, the reproductive systems of male and female embryos are identical
• at week 7 of gestation, the sex-determining region of the Y chromosome (SRY) stimulates the production of H-Y antigen, which acts on the gonads to differentiate into testes
• in the absence of H-Y antigen, the gonads differentiate into ovaries

Question 19

explain sexual differentiation - phenotypic

Answer 19

• the apparent anatomical sex of an individual and is dependent upon the gonadal sex
• as with undifferentiated gonads, embryos of both sexes have the potential to develop either male or female external genitalia and reproductive tracts
• in the presence of androgens secreted by the developing testes, male-type reproductive systems are developed
• the absence of androgens results in a female-type reproductive system

Question 20

what are the 2 primitive duct systems in the undifferentiated embryo

Answer 20

1. wolffian ducts
2. müllerian ducts

Question 21

explain wolffian ducts

Answer 21

• the placenta secretes human chorionic gonadotropin (hCG)
• if testes are present, hCG stimulates them to produce and secrete testosterone
• this testosterone will then stimulate the wolffian ducts to develop into the male reproductive system
• testosterone is also converted to dihydrotestosterone, which is responsible for the development of male external genitalia
• the testes secrete Müllerian-inhibiting factor, which causes the degradation for the müllerian ducts

Question 22

explain müllerian ducts

Answer 22

• in the absence of testosterone, the wolffian ducts degrade and the müllerian ducts develop into the female reproductive tract and external genitalia
• developing embryos are exposed to high levels of female sex hormones throughout gestation
• without the addition of testosterone, all fetuses would be feminized