Reproduction 2

Question 1

What are the different components of a sperm?

Answer 1

Head:

• Acrosome (contains enzymes for fertilization)
• Nucleus

Midpiece:
-Mitochondria

Tail (whiplike movements propel sperm)

Question 2

What is spermatogenesis? Process?

Answer 2

Production of sperm

Process:

• Chromosomes replicate
• Meiosis I (produces spermatocytes with 2n)
• Meiosis II (Produces four spermatids with 1n)
• Differentiation (Produces spermatazoa with 1n)

Question 3

How does sperm maturation occur?

Answer 3

Spermatazoa released into lumen of seminiferous tubules

• immotile
• 20days

Move to epididymis by peristaltic contractions and flow of lumenal fluid where they acquire motility

Move to vas deferens by peristalsis
-Remain in vas deferens until equaculation

Question 4

How is the sexual response in males controlled and how does it occur?

Answer 4

Controlled by autonomic nervous system through spinal reflexes in phases

Phases:

• Erection - parasympathetic nervous system
• Emission - sympathetic nervous system
• Ejaculation - sympathetic nervous system

Question 5

What are the receptors for sexual response in males?

Answer 5

Stimuli

• mechanoreceptors of penis and erogenous zones
• descending signals from higher brain centers

Question 6

How does emission occur?

Answer 6

Response to mechanical stimulation continues from erection to emission
-Neural activity shifts from parasympathetic control to sympathetic control

• Contractions of epididymus, vas deferens and ejaculatory duct
• Secretions from seminal vesicles and prostate
• Result - movement of semen in urethra

Question 7

What is the average sperm count?

Answer 7

Average volume of semen - 2.75ml (can be between 2-6ml)
-66million sperm/ml
therefore 180million sperm

Infertile sperm count is less than 20million

Question 8

What is the function of male reproductive tracts?

Answer 8

• Production of sperm

- Delivery of sperm to the female

Question 9

What is the function of female reproductive tracts?

Answer 9

• Production of ova
• Reception of sperm
• Transport of the sperm and ovum to common site for union
• Maintenance of the developing fetus until it can survive
• Giving birth (parturition)
• Nourishing the infant after birth (lactation)

Question 10

What are the characteristics of the female reproductive system?

Answer 10

• Cyclic changes in activity (menstrual cycle)
• Restricted periods of fertility (ovulation)
• Limited gamete production (pool established at birth)

Question 11

What are the female reproductive organs?

Answer 11

Gonads = ovaries
Reproductive tract = uterus, uterine tubes, vagina
External genetalia = vulva

Ovaries are the site of ova maturation consisting of connective tissue with follicles separate from reproductive tract

Question 12

Where are the follicles and what do they contain?

Answer 12

Found in the ovaries and contain one ovum

Question 13

What do granulosa cells do?

Answer 13

-Target cells of estrogen and FSH
which secrete chemical messengers in response
-Secrete inhibin which provides negative feedback to FSH secretion
-Transport nutrients to oocytes through gap junctions
-Secrete estrogens

Question 14

What is the vagina?

Answer 14

The female organ of copulation

• Wall contains smooth muscle
• Inner surface bathed in acid fluid secretion from uterus or glands in cervix (protects against bacterial infections)

Question 15

What is the uterus?

Answer 15

Site of fetal development

Question 16

What are the uterine tubes?

Answer 16

Also called fallopian tubes

-Ova transported from ovaries to uterus

Question 17

What is Oogenesis?

Answer 17

Creation of an ovum

Question 18

What is the menstrual cycle?

Answer 18

Repeated changes in the ovary and uterus through time

Includes:
Ovarian cycle
Uterine cycle

Caused by changes in estrogen and progesterone concentrations

Question 19

What are the two phases of the ovarian cycle?

Answer 19

• Follicular phase (mensturation approx 14 days)

- Luteal phase (Ovulation to before menstruation approx 14 days)

Question 20

What occurs during the follicular phase?

Answer 20

A few follicles begin to develop from primordial follicles

• Oocyte grows, granulosa cells proliferate
• Dominant follicle continues development
• FSH and estrogens stimulate follicle growth and development

Question 21

What occurs during the Luteal Phase?

Answer 21

• Ruptured follicle
• Corpus luteum secretes estrogens and progesterone
• Corpus luteum reaches max activity 10days, then degenerates
• If oocyte fertilized, degeneration does not occur

Question 22

How do fraternal twins occur?

Answer 22

• Two or more follicles may become dominant and released at ovulation
• If both are fertilized - fraternal twins
• Also called dizygotic twin

Question 23

What occurs during the menstrual phase of the uterine cycle?

Answer 23

• Shedding of uterine lining
• Blood flow to tissue decreases
• Tissues die and slough into vagina causing menstrual flow
• Triggered by decreased estrogens and progesterones

Question 24

What occurs during the proliferative phase?

Answer 24

• Uterus prepares for fertilized ovum
• Endometrial lining develops, the layer grows, the glands enlarge
• Smooth muscle layer thickens
• Cervical glands secrete mucus
• Estrogens stimulate development of uterine linings

Question 25

What occurs during the secretory phase?

Answer 25

Endometrium prepared for implantation

• Blood supply increased
• Glands enlarge and secrete glycogen-rich fluids
• Cervical secretions more sticky forming a plug

Question 26

How do hormones fluctuate during the menstrual cycle?

Answer 26

• Estrogen is first secreted from follicle, then from the corpus luteum
• Progesterone secreted from corpus luteum
• LH and FSH secreted from anterior pituitary
• Estrogens and progesterone inhibit LH and FSH secretion

Question 27

What are the actions of estrogens?

Answer 27

Follicular phase:

• Promote endometrial growth
• Promote oogenesis and follicle development
• Increase in LH secretion (late follicular phase)

Pregnancy and Luteal phase:

• Promote growth of duct tissue and deposition of fat in breasts
• Suppress lactation
• Increase in prolactin secretion
• Growth and contractile activity of uterine smooth muscle
• Promotion in fluid retention

Question 28

What are the actions of progesterone?

Answer 28

During Luteal Phase and pregnancy:

• Promotes secretory-phase uterine conditions
• Suppresses uterine contractile activity
• Promotes growth of glandular tissue in breasts
• Suppresses milk production