2 - Repro - Origin of the Sexes 2 Flashcards
At approx. which month of development do the testes reach the scrotum?
~ 9th month
What structure passes through the inguinal canal in females?
Round ligament of the uterus
Name the ligament which connects the ovary to the uterus:
Ovarian ligament
Name the ligament which connects the uterus to the labia majora:
Round ligament of the uterus
Name the syndrome caused by a (47, XXY) chromosome defect:
Klinefelter syndrome
If an embryo has no gonads due to a defect, would it develop male or female internal genitalia?
Female internal genitalia
- Mullerian ducts form, and Wolffian ducts regress due to lack of androgens
Is someone with Klinefelter syndrome a male or female?
Male, with small/undescended testes
Why may someone with Klinefelter syndrome have delayed/incomplete puberty?
Less than usual amount of testosterone produced
Name the syndrome caused by a (45, XO) chromosome defect:
Turner’s syndrome
Is someone with Turner’s syndrome a male or female?
Female, with no ovaries
When is Turner’s syndrome usually diagnosed? Why?
- At age when puberty usually occurs
- Girls with Turner’s syndrome do not go through puberty, due to lack of ovaries
If someone has a (46, XY) karyotype but the fetal genitalia is insensitive to testosterone and DHT, will they be born phenotypically female or male?
Female
- Have undescended testes
If someone has a (46, XX) karyotype but have excessive androgen secretion from adrenal glands, will they be born phenotypically female or male?
Male
List the reproductive hormones secreted by the hypothalamus:
- Peptide releasing factors
- GnRH
- PRH
- PIH (Dopamine)
List the reproductive hormone released by the posterior pituitary:
Oxytocin
List the reproductive hormones released by the anterior pituitary:
- FSH
- LH
- Prolactin
List the reproductive hormones released by gonads:
- Testosterone
- Oestrogens: Oestradiol, Oestrone, Oestriol
- Progesterone
- Inhibin
List the main reproductive hormones released by the placenta:
- hCG
- hPL
- Oestrogens: Oestradiol, Oestrone, Oestriol
- Progesterone
Which part of the pituitary gland is formed from the forebrain, and so called the ‘neurohypophysis’?
Posterior pituitary
Which part of the pituitary gland is formed from an evagination of the developing mouth ‘Rathke’s pouch’, and called the adenohypophysis?
Anterior pituitary
Approx how many seminiferous tubules are present in each testes?
~ 250 - 750 per testes
Name the cells found in the seminiferous tubules:
- Spermatocytes
- Spermatids
- Sertoli cells
- Myofibroblasts
- Leydig cells
What is the importance of the blood-testes barrier (tight junctions between sertoli cells in seminiferous tubules)?
The sperm are genetically different to the father’s cells, so must be kept apart otherwise high risk of autoimmune attack
Name the cells lining the rete testis and efferent ductules:
1) Columnar ciliated cells
2) Cuboidal cells (remove fluid and concentrate sperm)
What is the function of the cuboidal cells lining the rete testis and efferent ductules?
Absorb fluid, concentrating sperm
In what stage of meiosis does crossing over occur?
Prophase I
In what stage of meiosis does independent assortment take place?
Metaphase I
What is the main difference between meiosis in males and females?
Males = 1 germ cell forms 4 spermatogonia Females = 1 germ cell forms 1 oocyte
How many chromosomes is present in a gamete?
23 chromosomes
Approx. how many sperm are formed per day?
~ 200 million per day
