Exam 5: Spermatogenesis and Oogenesis

Question 1

What is spermatogenesis?

Answer 1

Process of the formation of sperm

Question 2

What is the site of formation of sperm?

Answer 2

Seminiferous tubule of the testicle

Question 3

What is spermatogenesis regulated by?

Answer 3

Testosterone

Question 4

When does spermatogenesis begin?

Answer 4

Puberty

Question 5

Look at the process of sperm cell development

Answer 5

Look at the process of sperm cell development

Question 6

What does the pampiniform plexus do?

Answer 6

Cools blood that comes into the testis

Helps recirculate testosterone in the testis

Question 7

Describe hormone regulation

Answer 7

Testosterone secreted by Leydig cells has a negative feedback
LH stimulates Leydig cells to secrete testosterone
FSH stimulates Sertoli cells to produce inhibin and convert testosterone to estrogen

Question 8

How is LH released for in spermatogenesis?

Answer 8

Pulsatile fashion

Question 9

What does the pulsatile fashion of LH release do?

Answer 9

Prevents refractoriness to sustained LH

Question 10

What is the spermatogenesis secretion of testosterone like?

Answer 10

Short and pulsatile

Question 11

What is essential for spermatogenesis?

Answer 11

Elevated testosterone in testis

Question 12

What are the 3 biological events involved in spermatogenesis?

Answer 12

Mitosis
Meiosis
Spermiogenesis

Question 13

What is mitosis in spermatogenesis?

Answer 13

Proliferation phases which allows for continual supply of germ cells

Question 14

What does meiosis allow for in spermatogenesis?

Answer 14

Allow for diploid to haploid
Allows for crossing over
Assures genetic diversity

Question 15

What is spermiogenesis?

Answer 15

Dramatic morphological changes from spermatids to spermatozoa

Question 16

What happens to spermatagonoia during spermatogenesis?

Answer 16

Migrate along Sertoli cells toward lumen of the tubule

Undergo maturation and become primary spermatocytes

Question 17

What is occurring during the process of spermatogonia becoming primary spermatocytes? What is special about this process?

Answer 17

Mitosis is occurring here

This is a heat sensitive process

Question 18

What happens to primary spermatocytes after they undergo meiosis I?

Answer 18

Forms 2 secondary spermatocytes with haploid

Question 19

What happens to secondary spermatocytes after they undergo meiosis II?

Answer 19

They become spermatids

Question 20

What is the cycle of seminiferous tubule?

Answer 20

Arbitrarily defined cellular associations that transition one to the next at predictable levels

Question 21

How many stage does a bull have in the cycle of the seminiferous tubule?

Answer 21

8

Question 22

How many cycles does complete spermatogenesis take?

Answer 22

4.5

Question 23

What temperature must spermatogenesis occur at?

Answer 23

3-7 degrees Celsius cooler than the body temperature

Question 24

What things are involved in the regulation of temperature?

Answer 24

Scrotal sweating
Tunica dartos muscle
Cremastor muscle
Pampiniform plexus

Question 25

What creates the blood testis barrier?

Answer 25

Sertoli cells are joined by tight junctions which effectively create a barrier from the immune system

Question 26

What does the blood testis barrier serve to do?

Answer 26

Allow metabolism of developing sperm to occur in a controlled environment

Question 27

Why are developing sperm not allowed to access the interstitial space?

Answer 27

The immune system will recognize them as foreign

Question 28

What chromosome do females contribute? Males?

Answer 28

Only X | X or Y

Question 29

What is the sex of the offspring determined by?

Answer 29

Whether an X or Y bearing sperm fertilizes the oocyte

Question 30

What is sperm composed of?

Answer 30

Head Midpiece Tail

Question 31

Describe the head of sperm

Answer 31

Contains the DNA | Acrosome cap contains enzymes which aid in fertilization

Question 32

Describe the midpiece of sperm

Answer 32

Contains mitochondria which provide power for the tail action

Question 33

Describe the tail of sperm

Answer 33

Flagellum like action provides movement | 1-4 mm/minute in fluid environment

Question 34

What is semen?

Answer 34

Sperm and associate fluid which are ejaculated

Question 35

What contribute to the fluid volume of semen?

Answer 35

Accessory sex glands

Question 36

What are the accessory sex glands?

Answer 36

Ampulla Prostate Seminal vesicles Bulbourethral glands

Question 37

What is oogenesis?

Answer 37

Development of the oocyte

Question 38

What happens to oogonia during prenatal growth?

Answer 38

They undergo meiosis

Question 39

Describe what happens to oogonia at birth

Answer 39

They enter meiosis near the time of birth but remain resting in prophase until puberty when meiosis resumes in a few cells each cycle

Question 40

What is produced following oogenesis?

Answer 40

1 ovum and 3 polar bodies

Question 41

What are the differences between male and female germ production?

Answer 41

Males constantly replenish germ cells through ongoing mitosis Females are born with all they will ever have and slowly deplete their supply Great increase in number of sperm by mitosis in the male Oogenesis involves only a limited number of oogonia each cycle