Chedy - theme 15

Question 1

Male reproductive structure: scrotum

Answer 1

Holds testes away from the body. Sperm develop at 2 degrees lower than core body temp.

Question 2

Sperm’s journey:

Answer 2

Developed in scrotum. Released into seminiferous tubules, where Leydig cells produce testosterone and Sertoli cells provide nutrients and protection. Reach maturation with motility and fertile in the epididymis. Vas deferens leads to ejaculatory duct.

Question 3

Composition of semen:

Answer 3

5% sperm, fluids from seminal vesicles, bulbourethral glands, and prostate.

Question 4

Acrosome:

Answer 4

An organelle developed in the Golgi apparatus that develops over the sperm head. It contains hyaluronidase and acrosine to break down the zona pellucida around the oocyte.

Question 5

Female reproductive tract: uterus

Answer 5

Endometrium: inner and glandular lining
Myometrium: outer muscular layer

Question 6

Embryonic tissue of male/female:

Answer 6

Labia majora is the same tissue as scrotum
Labia minora is the same tissue as urethral primordial tissue
Clitoris is the same tissue as the penis

Question 7

Endometrium: what it do

Answer 7

Without fertilization, it breaks down every month.

Question 8

Myometrium: what it do

Answer 8

Sensitive to progesterone, the main hormone in the second half of the menstrual cycle. Progesterone also provides stability during pregnancy.

Question 9

Hypothalamic regulation of pituitary gonadotropins:

Answer 9

GnRH is secreted in pulses. With normal pulsatility, FSH and LH are released for menstruation. In females, FSH and LH stimulate the ovaries to produce estrogen and progesterone. In males, FSH stimulates Sertoli cells and LH stimulates Leydig cells.

Question 10

What effect does the amount of GnRH have on menstrual cycle?

Answer 10

Counterintuitive - a high dose will actually block product synthesis. It’s the pulsatility, not the amount, that determines stimulation.

Question 11

Which sex has which hormones (mostly)?

Answer 11

Male - androgens

Female - estrogens and progesterone

Question 12

Effect of testosterone:

Answer 12

Development of male tissues like testes and prostate; promotes secondary sexual characteristics.

Question 13

Anabolic steroids mimic the effects of which cells?

Answer 13

Testosterone

Question 14

Timing of reproduction:

Answer 14

Tropical animals with stable climate and food source can reproduce all year round. Temperate animals’ reproductive cycles are controlled by photoperiod.

Question 15

Photocrine signalling:

Answer 15

Specialized retinal cells send light info to the suprachiasmatic nucleus. SCN can send two signals, to: pineal gland (melatonin) or hypothalamus (kisspeptin).

Question 16

Kisspeptin:

Answer 16

A brain protein produced in the hypothalamus that increases pulsatility of GnRH

Question 17

Pineal gland:

Answer 17

Pinecone-shaped structure in the middle of the brain. Secretes melatonin derived from tryptophan, regulates circadian rhythm.

Question 18

Melatonin:

Answer 18

Darkness hormone. Increases 10x at night. Short-day breeders get sexy during decreasing melatonin. Long-day breeders get sexy during increasing melatonin.

Question 19

Hormonal control of reproduction:

Answer 19

Negative feedback loop - sex hormones are inhibitory to hypothalamus and ant pit gland.

Question 20

Dual function of ovary:

Answer 20

Produces ova.

Endocrine organ - secretes estrogen and progesterone.

Question 21

Folliculogenesis:

Answer 21

Primary follicles join together to protect immature oocyte. Process ends when the remaining primary follicles are unable to respond to hormones.

Question 22

Oogenesis:

Answer 22

In the female fetus, a cohort of germ cells enter meiosis I and arrest until puberty. One gamete forms from each primary oocyte.

Question 23

Structure of ovum:

Answer 23

Two layers:
Zone pellucida - inside layer
Cumulus mass - the big thick layer all the way around

Question 24

Meiosis of ova:

Answer 24

Every meiotic division results in one large cell. In meiosis I, the secondary oocyte forms. In meiosis II, the polar bodies form. (Remember that only secondary oocyte becomes a mature egg; 3/4 haploid cells are polar bodies)

Question 25

Reproductive capabilities of ovaries - at birth and otherwise:

Answer 25

At birth, ovaries have a million arrested primary oocytes. By puberty, 200k are left. Each menstrual cycle, several oocytes begin maturation but only one is ovulated.

Question 26

Ovarian cycle:

Answer 26

Week 1 - primary follicles begin to develop.
Week 2 - one follicle continues development. Primary oocyte becomes secondary oocyte. Estradiol secretion begins.
Day 13 - cumulus oophorus opens and the oocyte is excreted. Oocyte becomes an ovum and is fertile. Ovum travels down fallopian tubes to be shed or implanted.

Question 27

Luteogenesis:

Answer 27

Ruptured follicle becomes corpus luteum, a steroidiogenic cluster of cells that maintains the endometrium (lots of progesterone, some estrogen).

Question 28

Progesterone and estrogen curves:

Answer 28

Estrogen peaks before ovulation, progesterone peaks slowly during luteal phase.

Question 29

Follicular phase: first half of menstrual cycle

Answer 29

Growth and differentiation of follicle. FSH and a lil LH promote slow increase of estradiol release. Estradiol has a negative feedback loop with FSH and LH to keep them from rising before oocyte is ready. When it is, estradiol production jumps, and becomes a pos feedback loop with LH, inducing ovulation.

Question 30

Luteal phase:

Answer 30

Corpus luteum develops and secretes progesterone. FSH and LH are inhibited. If fertilization occurs, cells surrounding embryo will produce hCG to maintain corpus luteum. If fertilization does not occur, corpus lutem degenerates over 2 weeks.

Question 31

Phases of menstruation:

Answer 31

Follicular (menstrual and proliferative), luteal (secretory)

Question 32

Menstrual cycle (the phase):

Answer 32

Begins when corpus luteum breaks down.

Question 33

Estrous cycles:

Answer 33

Some animals menstruate without bleeding. In the proliferative phase, endometrium thickens and becomes more vascularized. In the secretory phase, glands develop to sustain the embryo. If embryo does not implant, the lining is shed. If embryo implants, pregnancy begins.

Question 34

PMS:

Answer 34

A collection of physical and emotional symptoms. Starts at the end of the luteal phase.

Question 35

Hormonal contraception:

Answer 35

1. Combined method - progestin and estrogen suppress ovulation.
2. Progestogen only - progesterone or progestin reduces frequency of ovulation and changes cervical mucus.