Reproduction Flashcards
First Law of Segregation (Disjunction)
- Mendel
The distribution of homologous pairs of chromosome to the 2 intermediate daughter cells is random with respect to paternal origin
Segregation
- Mendel
Separating of two homologous chromosomes
Second Law of Independent Assortment (Crossing Over)
- Mendel
Inheritance of one allele has no effect on the likelihood of inheriting certain alleles for other genes
Chiasma
Point of synapsis (where the chromosomes cross each other) where recombination occurs
X Chromosome
Carries a sizeable amount of genetic info; mutation in these genes cause sex linked (x-linked) disorders
Y Chromosome
Contains very little genetic info; Contains a sex determining region (SDR)
Follicle Stimulating Hormone (FSH) in Males
Stimulates the sertoli cells (nourish sperm) and triggers sperm maturation in the seminiferous tubules
Luteinizing Hormone (LH) in Males
Causes the interstitial cell of leydig to produce testosterone and other androgens (male sex hormones) - resulting in secondary sex characteristics
Spermatogenesis
- Spermatogonia (diploid - 2n)
- S Stage replicates DNA
- Primary Spermatocytes (diploid - 2n)
- Meiosis I
- Secondary Spermatocytes
- Meiosis II
- Spermatid (haploid - n)
- Maturation
- Spermatozoa (4 cells total)
Acrosome
Part of the sperm:
Derived from the golgi apparatus to penetrate the ovum
Tail and End Piece
Part of the sperm:
Consists of flagellum which gives the sperm its motility
Parts of the Sperm
- Acrosome [head]
- Plasma Membrane [head]
- Centriole [mid piece]
- Mitochondria (generate ATP to be used) [mid piece]
- Axial Filament [tail piece]
- flagellum [end piece]
Path of Ejaculation
Seminiferous tubules Epididymis Vas deferens Ejaculatory duct N(othing) Urethra Penis Seminal fluid
Seminiferous Tubules
Sperm are formed here
Epididymis
Flagella gain motility and are stored here until ejactulation
Vas Deferens
Ejaculation travels through here
Ejaculatory Duct
Ejaculation travels through here
Urethra
Where two ejaculatory ducts fuse (sperm + urine)
Penis
Sperm leave the body here
Seminal Fluid
Mixed with sperm during ejaculation to help combat the acidic vaginal environment and prevent sperm with nutrients
Seminal Vesicle
Contributes fructose to seminal fluid to nourish the sperm
Prostate
Contribute alkaline properties to seminal fluid to allow sperm survival in acidic female environment
Bulbourethral (Cowper’s) Gland
(Pre-Cum) : Produce a clear, viscous fluid that cleans out any remnants of urine and lubricates the urethra
Estrogen
- Secreted in response to FSH resulting in development and maintenance of female reproductive system and secondary characteristics.
- Leads to thickening of endometrial lining
- Estrogen establishes the endometrium
Progesterone
- Secreted by the Corpus Luteum
- Protects the endometrium
Corpus Luteum
Rementant follicle that remains after ovulation in response to LH
Path of Egg Through the Female Reproductive System
- Egg in Ovaries
- Egg ovulated through peritoneal sac (1 per month)
- Egg drawn into fallopian tube or oviduct cilia propel the egg forward
- From Fallopian tube into uterus - will remain here if it is a zygote
- Lower end of uterus (cervix) connects to the vaginal canal
- Vaginal canal leads to the vulva (external anatomy)
Path of Sperm Through the Female Reproductive System
- Sperm deposited in vaginal canal
- Moves from vaginal canal to the cervix (lower end of the uterus)
- Into the uterus
- From uterus to Fallopian tube- where it will reach the egg if woman is ovulating
Oogenesis
*All oogonia are formed as a fetus (by birth al oogonia have undergone DNA replication and are primary oocytes (2n) and arrested in Prophase I
- Primary oocytes (diploid - 2n)
- Meiosis I
- Secondary oocyte (ovulation) - remains arrested in metaphase II unless fertilization occurs
Zona Pellucida
Mix of glycoproteins that surrounds the oocyte to protect the egg and necessary for sperm cell binding
Corona Radiata
Outer layer that adheres to egg during ovulation. Meiosis II is triggered when a sperm penetrates this layer with enzymes
Menstrual Cycle Phases
- Menstruation
- Follicular Phase (pre-ovulatory)
- Ovulation
- Luteal Phase (post-ovulatory)
Follicular phase
Menstrual flow sheds uterine lining of previous cycles
- Low Estrogen and Progesterone (to regrow endometrial lining)
- GnRH increases
- FSH and LH increase to develop ovarian follicles
Ovulation
Release of secondary oocyte egg through the peritoneal sac (one per month)
- Increase LH to induce ovulation
- Estrogen, FSH and GnRH all increase
Luteal Phase
After ovulation the LH causes ruptured follicle to form the corpus luteum
- Progesterone increases as it is secreted by the corpus luteum
- GnRH, FSH and LH decrease to prevent ovulation of multiple eggs
- Estrogen remains high
Menstruation
No implantation of egg means the uterine lining is sloughed off
- Progesterone and Estrogen decrease
- GnRH is increased starting a new cycle
Menopause
Ovaries are less sensitive to FSH and LH resulting in ovarian atrophy
- Estrogen and Progesterone levels drop
- Blood levels of FSH and LH increase with no more negative feedback
- Endometrium atrophies
- Menstruation stops
Pregnancy
Zygote becomes a blastocyst which implants in the uterine lining which secretes human chorionic gonadotropin (hcG) to maintain corpus luteum
- Progesterone and Estrogen increase (during the second trimester the placenta will secrete these to prevent GnRH secretion)
