Diagrams & Processes (Reproduction)

Question 1

1. What is the function of the scrotum and the cremaster and dartos muscles?

Answer 1

To regulate the temperature of the testes. They contract in cold temp to bring testes closer to body and wrinkle scrotum which reduces heat loss and relax in hot temp to lower testes, smooth out scrotum to allow cooling.

Question 2

2. Describe the structure of the testes.

Answer 2

Paired oval glands in the scrotum, 5cm by 2.5cm diameter. Serous membrane=Tunica vaginalis

covers tough white connective tissue layer of tunica albuginea. Septa of tunica albuginea form 200300 lobules within testis. Seminiferous tubules (1-3) fill each lobule.

Question 3

3. Where in the testes are sperm produced?

Answer 3

Seminiferous tubules

Question 4

What are the functions of the Sertoli and Leydig cells and where in the testes are they located?

Answer 4

Sertoli cells- form blood-testis barrier, support and protect developing spermatogenic cells, release sperm into lumen of seminiferous tubule, produce fluid for sperm transport, secrete inhibin when sperm numbers sufficient for efficient reproduction. Located inside seminiferous tubules.

Question 5

Leydig cells

Answer 5

secrete testosterone. Located between adjacent seminiferous tubules.

Question 6

How does anaphase I of meiosis differed from anaphase of mitosis and anaphase II of meiosis?

Answer 6

Paired chromatids remain attached at centromere, ie. Chromosome pairs are separated rather than

the chromatids of the individual chromosomes.

Question 7

What is the significance of meiosis I?

Answer 7

Reduction division, as each resulting cell contains the haploid number of chromosomes because it contains only one member of each pair of homologous chromosomes present in the starting cell.

Question 8

Describe the process of spermatogenesis, including the final stage, spermiogenesis.

Answer 8

Spermatogenesis takes 65-75 days. Spermatogonia (2n) undergo mitosis and some spermatogonia stay near basement membrane while others squeeze through blood –testis barrier, undergo developmental changes and become primary spermatocytes (2n). Meiosis I begins and secondary spermatocytes (n) are formed. Meiosis II forms 4 spermatids (n). Cytoplasmic bridges link the 4 spermatids. In the final stage, spermiogenesis, spermatids are freed from their cytoplasmic bridges

and elongate to form sperm cells.

Question 9

What are the functions of the sperm cell acrosome and middle piece?

Answer 9

Acrosome-enzymes contained within cap like vesicle help sperm penetrate a secondary oocyte to complete fertilisation

Question 10

Describe the hormonal control of spermatogenesis and testosterone secretion.

Answer 10

LH stimulates Leydig cells to release testosterone. FSH and testosterone act synergistically to cause spermatogenesis. FSH acts on the Sertoli cells to begin meiosis and FSH and testosterone stimulate Sertoli cell secretion of androgen-binding protein (ABP) which maintains high levels of testosterone

necessary for final stages of spermatogenesis in seminiferous tubules.

Question 11

What are the functions of testosterone?

Answer 11

Pre-natal testosterone causes development of male reproductive organs and ducts, later causes development of male sexual characteristics, sexual function and stimulation of anabolism.

Question 12

List the components of the duct system of the male reproductive system in order, from testes to urethra.

Answer 12

Seminiferous tubules, straight tubules, rete testis, efferent ducts, ductus epididymis, ductus (vas) deferens, ampulla of ductus deferens, ejaculatory duct, prostatic urethra.

Question 13

Name the structures in the spermatic cord.

Answer 13

Ductus (vas) deferens, testicular artery, veins from testes, nerves, lymph vessels, cremaster muscle.

Question 14

Describe the entry of the spermatic cord through the abdominal wall.

Answer 14

Passes through the inguinal canal which is an oblique passage way about 4-5cm long, in the anterior abdominal wall.

Question 15

What are the three subdivisions of the male urethra?

Answer 15

Prostatic, membranous and spongy urethra

Question 16

Describe the locations and functions of the accessory sex glands.

Answer 16

Seminal vesicles- paired convoluted pouch-like structures about 5cm long, posterior to base of

urinary bladder, joins ampulla of ductus deferens before forming ejaculatory duct. Secrete alkaline

Question 17

Which accessory sex gland contributes the majority of seminal fluid?

Answer 17

Seminal vesicles

Question 18

Which tissue masses form the erectile tissue in the penis and how do they become rigid during sexual arousal?

Answer 18

Corpora cavernosa (paired) and corpus spongiosum. Parasympathetic fibres cause dilation of smooth muscle in arterioles of erectile tissue which allows increased blood filling and closes off veins draining the erectile tissue.

Question 19

Which tissue mass keeps the urethra open during ejaculation?

Answer 19

Corpus spongiosum

Question 20

Explain the physiological processes involved in ejaculation.

Answer 20

Sympathetic reflex; peristaltic contractions of epididymis, ductus deferens, seminal vesicles, ejaculatory ducts and prostate propel semen into spongy urethra prior to ejaculation, smooth muscle sphincter at base of bladder closes, musculature of penis contracts.

Question 21

What are the functions of the ovaries?

Answer 21

Production of secondary oocytes, that develop into mature ova after fertilisation, production of the hormones, estrogen, progesterone, inhibin and relaxin

Question 22

How are they held in place in the pelvic cavity?

Answer 22

Broad ligament of the uterus and mesovarium enclose ovaries and attaches them to pelvic wall; ovarian ligament anchors ovaries to uterus; suspensory ligament attaches ovaries laterally to the pelvic wall.

Question 23

Which structures in the ovary serve an endocrine function, and which hormones do they secrete?

Answer 23

Follicles produce estrogen. Corpus luteum secretes progesterone, estrogen, relaxin and inhibin

Question 24

How does the age of a primary oocyte in a female compare with the age of a primary spermatocyte in a male?

Answer 24

Primary oocytes are produced during foetal development while primary spermatocytes are produced after puberty in males.

Question 25

From which follicle does ovulation occur?

Answer 25

Mature (Graafian) follicle

Question 26

Relate meiosis I and meiosis II to the development of follicles during oogenesis and after ovulation.

Answer 26

Meiosis I begins in foetus and is completed after puberty when secondary oocyte is formed from

primary oocyte. Meiosis II starts with the secondary oocyte which is ovulated at metaphase II stage. Fertilisation by the sperm completes meiosis II. If fertilisation does not occur meiosis II is not

completed.

Question 27

Where are the uterine tubes located?

Answer 27

They extend about 10cm, laterally from the top of the uterus.

Question 28

What are the functions of the cells that line the uterine tubes?

Answer 28

To sweep the fertilised ovum (or secondary oocyte) toward the uterus via action of the cilia.

Question 29

What are the principal parts of the uterus?

Answer 29

Fundus (dome shaped superior portion), body (tapering central portion), cervix (inferior narrow portion).

Question 30

How is the uterus held in its normal position in the pelvic cavity?

Answer 30

paired broad ligaments attach it to pelvic cavity; paired uterosacral ligaments connect uterus to sacrum; cardinal ligaments extend from the cervix to the vagina and lateral pelvic wall; round

ligaments extend from uterus to labia majora.

Question 31

Which of the structural features of the endometrium and myometrium contribute to their function?

Answer 31

Endometrium- 2 layers of endometrium, the stratum functionalis which sloughs off during menstruation and stratum basalis, which gives rise to new stratum functionalis after each menstruation.

Myometrium- 3 layers of smooth muscle fibres that function in labour and childbirth.

Question 32

What are the functions of the vagina?

Answer 32

Receptacle for the penis during intercourse, outlet for menstrual flow, passageway for childbirth

Question 33

What structures comprise the vulva?

Answer 33

External genetalia of the female comprised of mons pubis (adipose tissue that cushions pubic symphysis), labia majora (2 protective longitudinal folds of skin), labia minora (2 smaller protective folds of skin), clitoris (cylindrical mass of erectile tissue), vestibule (region between labia minora), bulb of vestibule (2 elongated masses of erectile tissue deep to labia on either side of vaginal orifice).

Question 34

Which structures in males are homologous to the ovaries, the clitoris, the greater vestibular glands, the bulb of the vestibule?

Answer 34

Ovaries-testes

Clitoris- glans penis

Greater vestibular glands- bulbourethral glands

Bulb of vestibule- corpus spongiosum and bulb of penis

Question 35

Which surface structures are anterior to the vaginal opening?

Answer 35

Mons pubis, external urethral orifice, clitoris

Question 36

Which surface structures are lateral to the vaginal opening?

Answer 36

Labia majora and labia minora

Question 37

How are breasts supported?

Answer 37

Suspensory ligaments

Question 38

Through which structures does milk pass from its production site to its exit from the breast?

Answer 38

Alveoli, secondary tubules, mammary ducts, lactiferous sinuses, lactiferous ducts, exterior.

Question 39

Which hormones regulate the synthesis and ejection of milk?

Answer 39

Synthesis – prolactin, estrogens, progesterone

Ejection- oxytocin