Topic 14: Reproduction I

Question 1

What are some types of asexual reproduction?

Answer 1

budding
fission
fragmentation and regeneration
parthenogenesis

Question 2

Advantages if asexual reproduction?

Answer 2

rapid
all of organisms genes passed on
don’t need to find a mate

Question 3

Define sexual reproduction?

Answer 3

reproduction involving production and fusion of gametes

Question 4

Characteristics of sperm? egg?

Answer 4

small, motile, flagellated

large, nonmotile, contains nutrients for embryo

Question 5

Disadvantages of sexual reproduction?

Answer 5

“reproductive handicap” - only 1/2 of population can actually reproduce
only half of organisms genes passed on

Question 6

Advantages of sexual reproduction?

Answer 6

promotes genetic diversity
new combinations of alleles:
- get rid of harmful alleles or combinations of alleles
- offspring may be more fit than parent
- more likely that some of population can survive enviormental changes

Question 7

What are the functions of the male reproductive system?

Answer 7

make sperm

deliver sperm to female reproductive tract

Question 8

Acronym to remember pathway of sperm

Answer 8

SEVEn UP

Question 9

What are the testes?

Answer 9

male gonads (reproductive organs)

Question 10

What does the testes include?

Answer 10

seminiferous tubules: site of spermatogenesis
hollow long tube, very small in diameter
leydig cells: produce testesterone and other sex hormones - scattered between seminiferous tubules

Question 11

What is the epididymis and what does it do?

Answer 11

coiled tube above testes (6m long)
transport system - takes about 3 weeks
maturation of sperm
storage of sperm

Question 12

What is the scrotum and what does it do?

Answer 12

skin-covered sac - contains testes and epididymis
external in most mammals, suspended from body
cooler than body temperature to improve sperm production and longevity

Question 13

What are the 2 types of ducts that the male reproductive system has?

Answer 13

vas deferens: sperm sucts - 1 from each epididymis
extend from scrotum to behind the bladder
ejaculatory duct: passes through prostate gland, joins urethra

Question 14

What is the penis, what does it do and what does it contain?

Answer 14

copulatory organ
delivers sperm into female reproductive tract
contains urethra: carries urine and semen through penis

Question 15

What is erectile tissue and what happens to it during sexual stimulation?

Answer 15

3 parallel columns of tissue
during sexual stimulation:
- NO released from endothelial cells
- arterial smooth muscles relax
- dilate arteries/ compress veins -> blood enters faster than it leaves

Question 16

What are glans and what are they homologous with?

Answer 16

tip of penis, contains most sensory neurons

homologous with clitoris in females

Question 17

What is the prepuce?

Answer 17

cuff of loose-fitting skin (foreskin), removed in circumcision

Question 18

What is semen made of?

Answer 18

sperm and fluids from accessory glands

Question 19

What do the seminal vesicles do?

Answer 19

secrete fluids into vas deferens
about 60% of semen volume
fluoresces - forensically important
Produce fluids rich in:
- fructose - E for sperm after ejaculation
- prostaglandins - stimulate contractions of uterus - help move sperm up female reproductive tract

Question 20

What does the prostate gland contain, secrete and statistics?

Answer 20

contains anticoagulant enzymes and citrate (nutrient)
secretes into urethra
> 1/2 of men >40 have enlarged prostate
about 3% of men die of prostate cancer

Question 21

What is the bulbourethral gland and what happens before ejaculation?

Answer 21

2 small round glands on either side of urethra
BEFORE ejaculation:
- secrete bulbourethral fluid into urethra - clear mucus to neutralize any acidic urine (contains sperm as well)

Question 22

Where is sperm produced?

Answer 22

in seminiferous tubules in testes

Question 23

Where is sperm stored and where does it travel through?

Answer 23

epididymis

Question 24

Where does sperm travel through during ejaculation?

Answer 24

travels from epididymis through vas deferens

Question 25

What is spermatogenesis? When does it happen?

Answer 25

production of mature sperm cells | about 7 weeks in humans, continuous after puberty

Question 26

What happens in embryonic testes before the male is born?

Answer 26

primordial germ cells divide, differentiate into spermatogonial stem cells

Question 27

What happens in mature testes (at/after puberty)?

Answer 27

spermatogonial stem cells divide via mitosis -> spermatogonia undifferentiated cells in walls of seminiferous tubules maintained via mitotic divisions some become primary spermatocytes

Question 28

How does a primary spermatocyte divide and what does it produce?

Answer 28

divides via meiosis 1 | meiosis 1 -> secondary spermatocyte

Question 29

How does a secondary spermatocyte divide and what does it produce?

Answer 29

divides via meiosis 2 | meiosis 2 -> spermatids

Question 30

What are the three parts of a sperm cell?

Answer 30

head, midpiece, tail

Question 31

What are androgens? Which is the most important? What is it needed for? What does it stimulate?

Answer 31

principle sex hormones in males testosterone - needed for spermatogenesis - growth of primary male sex characteristics - sex organs stimulates puberty -> secondary sex characteristics - physical, behavioral differences between males and females that aren't needed for reproduction - i.e. facial/ body hair, deep voice, muscle development about 10X higher in males than females

Question 32

What hormone does the hypothalamus release?

Answer 32

gonadotropin-releasing hormone (GnRH)

Question 33

What hormones do the anterior pituitary release?

Answer 33

luteinizing hormone | follicle stimulating hormone

Question 34

What hormone do the leydig cells release?

Answer 34

testosterone

Question 35

What does the sertoli cells produce?

Answer 35

androgen binding protein | inhibin

Question 36

What does the follicle stimulating hormone stimulate?

Answer 36

stimulates: - the development of seminiferous tubules - sertoli cells to produce, secrete androgen binding protein (ABP) sertoli cells binds testosterone and helps maintain high testosterone levels in testes

Question 37

What is FSH secretion inhibited by and what does this do?

Answer 37

inhibited by inhibin: peptide hormone secreted by sertoli cells