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Repro 2
sex determination
30
Physiology
Undergraduate 3
11/03/2015

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Cards

Term
Which 2 anterior pituitary hormones are controlled by both releasing AND inhibiting hormones?
Definition
PRL & GH
Term
The hypothalamus releases ______ which targets the _____ to release ______. This targets the breast tissue
Definition
PRH
anterior pituitary
breast
Term
Describe the structure of the mammary gland
Definition
15-20 milk lobes divided by adipose tissue

each lobe is subdivided into lobules

lobules contain alveoli

alveoli secrete milk
Term
Where does milk accumulate during nursing?
Definition
in the lumen of the lactiferous duct
Term
Alveoli secrete milk into _______
Definition
secondary tubules
Term
What effect does prolactin have on mammary glands?
Definition
stimulates milk production & growth and development of glands & ducts
Term
True or False, estrogen inhibits secretion of prolactin
Definition
true
Term
Why is milk production inhibited during pregnancy?
Definition
the placenta produces estrogen, which targets the hypothalamus to secrete PIH which inhibits the anterior pituitary from secreting prolactin
Term
What hormone controls milk production?
Definition
prolactin
Term
What hormone controls milk release?
Definition
oxytocin
Term
Oxytocin is released from the ______
Definition
posterior pituitary
Term
What triggers oxytocin release?
Definition
suckling stimulus, visual cues or auditory cyes
Term
Aside from triggering milk ejection, what other effect does oxytocin have?
Definition
it increases trust among humans
Term
True or False

Oxytocin is made by both males and females
Definition
true
Term
Where is the SRY gene found?
Definition
on the Y chromosome of all animals
Term
What causes sex differentiation into the female phenotype?
Definition
1. no SRY protein - gonadal tissue develops into ovaries
2. No testosterone, so Wolffian duct degenerates
3. No MIF so Mullerian duct becomes fallopian tubes/uterus/vagina
Term
What causes sex differentiation into the male phenotype?
Definition
1. SRY protein present - gonadal tissue develops into testes
2. Testosterone peresent so sertoli cells produce MIF, which maintains the Wolffian duct, Mullerian duct degenerates
3. Testosterone present so Wolffian duct becomes seminal vesicles, vas deferens, epidydimis
Term
All nucleated cells of the body except eggs & sperm contain how many chromosomes? How many are autosomes? How many sex chromosomes?
Definition
46

22 pairs of autosomes

1 pair of sex chromosomes
Term
Eggs and sperm each contain how many chromosomes?
Definition
23
Term
True or False

The SRY gene is necessary but not sufficient for testes development
Definition
False

necessary AND sufficient
Term
How can a mouse show a female phenotype but by SRY positive, XY positive?
Definition
Malfunctions in all 3 of the following insulin receptors will result in female phenotypes:

INSR
IGF1R
INSSR
Term
What are true hermaphrodites? What are the possible karyotypes?
Definition
They have both ovarian and testicular tissue

47XXY
46XX/46XY
46XX/47XXY
Term
What are pseudohermaphrodites?
Definition
Have external genitalia of one gender and internal sex organs of another
Term
What is the genetic 'issue' that is causing pseudohermaphroditism?
Definition
an endocrine disorder

males with a defective 5a-reductase gene
Term
What does 5a-reductase do?
Definition
converts testosterone to DHT (a potent androgen)
Term
Why does a defect in the 5a-reductase gene cause pseudohermaphroditism?
Definition
-lack of exposure to androgens in early gestation means male external genitalia don't fully develop during fetal development
-once puberty is reached, the testes resume testosterone secretion causing masculinization of external genitalia & secondary sex characteristics
Term
True or False, girls undergo the rapid growth & development of puberty earlier than boys
Definition
true
Term

What is the difference between puberty & adolesence?

 

forget this card they're both the same

Definition

puberty is the activation of HPF axis which causes maturation of the gonads

 

adolesence is the maturation of social & cognitive behaviours associated with adults

Term
What can you do to treat children with GnRH deficiencies?
Definition
administer GnRH pules to mimic the natural release pattern, will trigger puberty
Term
True or False

People living at higher altitudes have a later onset of puberty
Definition
true
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