Reproductive system 1 Flashcards
Compare and contrast asexual with sexual reproduction
Number of parents: one vs two
Type of cell division: mitosis vs meiosis (and mitosis before puberty)
Variability of offspring: clones vs genetically variable
Advantages: abundancy vs variability and adaptation
How do bacteria produce
both sexually (conjugation) and asexually (binary fission) – they decide to produce asexually when the environment is stable and sexually when it changes (greater chance of survival with greater genetic variability) – competent bacteria
What is spermatogenesis/oogenesis? What is caused by testosterone/estrogen and progesterone?
production of sperm cells and production of testosterone by testes
production of egg cells and estrogen and progesterone by ovaries
primary and secondary sex traits in men/women
Female reproductive system anatomy (structures and their functions) – draw an annotated diagram
1) Uterus – muscle composed of a myometrium and the endometrium which supports and nurtures the embryo
a. Myometrium – thick layer of smooth muscle (produces contractions during labor)
b. Endometrium – thin inner lining (changeable thickness, menstruation, and pregnancy dependent). If a person has never been pregnant the opposite sides of the endometrium stick together, creating a virtual cavity, and if they have then there is an actual cavity
2) Cervix – thick and firm neck of uterus located between the uterus and vagina that provides support during pregnancy (keeps the baby inside the uterus) and dilates during childbirth
3) Fallopian tube (oviduct) – collects ovulated eggs and the site of fertilization, an early embryo moves down the oviduct towards the uterus
4) Fimbriae – protrusions inside the uterine tube that constantly vibrate and attract ovulated egg cells (otherwise, they float away and fertilization can happen in the abdominal cavity)
5) Ovaries – site of oogenesis
6) Clitoris – same structure as erectile tissue in the penis
7) Labia majora and labia minora make the vulva (external part of female reproductive system) which protects the internal parts of the reproductive system
8) Vagina – creates birth canal during labor
Sex determination of the embryo
Early embryo (from conception till 8th week) develops gonads (sex glands) that can become both ovaries and testes. There is a sex determining region on the Y chromosome (SRY gene) so if Y chromosome is present, the region will stimulate the production of TDF (testis determining factor) protein which stimulates testes development. Testes develop testosterone which then definitely leads to the development of male primary and secondary sex traits.
If there is no Y chromosome, no testosterone gets produced and so the maternal estrogen and progesterone lead to ovary development
Male reproductive system anatomy (structures and their functions) – draw an annotated diagram
1) Testes – site of spermatogenesis, made out of thousands of seminiferous tubules (convoluted hollow tubules)
2) Each seminiferous tubule is surrounded by a basement membrane and has a thick wall with multiple cell layers:
a. at the edge are germinal epithelial cells that undergo mitotic division until puberty to replenish spermatogonia that grow into larger cells with a rich cytoplasm called primary spermatocytes (sperm cells are made from germinal epithelium)
b. in puberty, they are stimulated to go through meiosis, and daughter cells called spermatids are pushed toward the interior of the tubule (they are tailless and need to differentiate)
c. in the differentiation process into sperm cells, they go further towards the center, and at one point they detach from the wall and swim through the tubule towards the epididymis
d. Sertoli cells in the seminiferous tubules nourish and allow spermatocytes to differentiate to spermatozoa and later into sperm cells
3) Epididymis(highly tubular structure) is a physical extension of the testes where sperm mature – they become fully mobile and are deposited until ejaculation
4) Vas deferens, also called sperm duct, leads from epididymis into the seminal vesicle
5) The seminal vesicle produces an alkaline liquid (made out of proteins, the reason why semen is sticky) that combines with sperm cells and gets into the prostate gland
6) In the prostate gland, more fructose, glucose, and alkaline fluid are produced and that is how semen is created. Fructose and glucose in the semen are a source of ATP that sperm cells require for movement. The alkaline properties of the fluid neutralize the acidity of the vagina and allow sperm cells to survive
7) The urethra is a common duct for semen and urine
8) Penis has erectile tissue (gland penis, foreskin)
9) Scrotum hold the testes and epididymis at a lower than body temperature
10) The pubic bone is a part of the pelvis
11) In between seminiferous tubules there is interstitial fluid and interstitial cells (Leydig cells) that produce testosterone.
12) There are also blood vessels in the interstitial space that distribute the testosterone produced since interstitial cells are a part of the endocrine system
Stages germ cells goes through to become a mature sperm cell:
- Primordial germ cell
(mitosis, slight differentiation) - Spermatogonium
(mitosis, slight differentiation, DNA replication) - Primary spermatocyte (2n)
(meiosis I) - Secondary spermatocyte (n)
(meiosis II) - Spermatids (n)
(differentiation) - Spermatozoa (released into the lumen of the tubule and travels to the epididymis)
- Mature sperm cells
