Sexual Behavior Flashcards
What are the advantages of sexual reproduction? Why do we have sex instead of asexual reproduction?
+Decrease pathogens and limit mutations
How many sets of chromosomes do we have?
How many sets of autosomes?
How many sets of sex chromosomes?
23 sets of chromosomes
22 sets of autosomes
1 set of sex chromosome
What type of sex chromosome (genotypes) are females vs. males? (XX vs. XY)
Females = XX Males = XY
Which chromosome determines sex?
X or Y?
Y - in a vacuum, we can say males determine sex of baby
Up to the ___ week, males and females have undifferentiated primordial gonads.
What happens after this week?
Up to the 6th week…
If the cell contains a Y-chromosome, at about the 6th week, the sex-determining region of the Y chromosome (SRY) gene is expressed in MALES.
When the SRY gene is expressed, it encodes the Testes Determining Factor, and turns the gonad tissues into Testes.
When the SRY gene is expressed, what does it encode?
It encodes the Testes determining factor.
It turns the gonads into Testes.
What happens once the gonads have been determined as either Testes or Ovaries?
If Testes, it produces testosterone.
If Ovaries, they do NOTHING.
What are the 2 systems that make up the internal sex organs?
- Wolffian system - Male, develops into epididymis and the seminal vesicles (ball sack).
- Mullerian system - Female, develops into fimbria, fallopian tubes, uterus, inner 2/3 vagina
What happens after the gonadal tissue develops into testes?
*2 things that have to happen in order to develop into a male…
2 things will happen:
- It starts to produce testosterone. That testosterone will stimulate the Wolffian system to develop.
- It will also secrete ANTI-MULLERIAN hormone to suppress the Mullerian system.
What happens if you don’t have the anti-mullerian hormone but have testosterone, what system will you get?
You get development of both systems for internal organs.
What happens if you have anti-mullerian hormone, but don’t have testosterone, what system will you get?
You will get no internal sex organs.
Describe the chromosomal malfunction of Turner’s syndrome.
What type of sex organs do they have/not have?
Condition that results from either an incomplete pairing of gametes, or pairing of X with O gamete - O gametes have no sex chromosomes (XO).
There is no gonads (No Y) or ovaries (need both XX).
However, Mullerian system develops so the internal and external sex organs are female.
In the absence of any hormones, what’s the default form?
Females - nature favors the female.
Can ppl with Turner’s syndrome get pregnant?
They cannot have biological children bc they don’t have gonads - but they CAN carry babies to term with embryo implants and hormone supplementation bc they have the internal (uterus) and external organs.
What type of genotype do Klinefelter syndrome patients have?
What type of internal and external sex characteristics?
XXY - due to the SRY gene of the Y chromosome, they develop testes.
Internal and External = Male characteristics
They do sometimes have feminine characteristics (pubic hair, fat distribution)
What type of genotype do Jacob’s syndrome patients have?
How did they get that genotype?
What type of internal and external sex characteristics?
What are some of non-sexual symptoms of Jacob’s syndrome?
XYY
Due to problems during fertilization - There’s 2 Y’s instead of 2 X’s…
Produce Testes Determining Factor due to their Y chromosome - Internal & External male characteristics.
Acne, tallness, lean… fertility issues.
What were inmates with XXY or Jacob’s syndrome in jail for?
Why does this matter?
They were in jail for things like theft… it was mostly NON-VIOLENT crimes - this disproved the theory that an extra Y chrom. made them more aggressive (due to excess testosterone).
What type of genotype do Androgen-Insensitivity Syndrome (AIS) patients have?
What type of internal and external sex characteristics?
XY genotype - BUT defective Testosterone receptors.
XY = Gonads become Testes and secrete Testosterone and Anti-Mullerian hormone BUT bc of the defective Testosterone receptors, there is NO development of the Wolffian system. The testes don’t descend. - AIS - They HAVE NO INTERNAL SEXUAL ORGANS.
Since Wolffian system is not stimulated, it withers away.
Anti-Mullerian hormone IS recognized and suppressed-so there is no Internal sex organs, but externally develop female sex organs since androgens are not recognized- default to female form.
What do you need to develop external genitalia into male sex pattern?
Androgens (testosterone)
If someone fails to menstruate or grow secondary hairs during puberty - what type of syndrome might they have and why?
They probably have AIS - androgen-insensitivity syndrome. They do not have internal female sex organs.
The secondary hair factor is controlled by testosterone - and AIS is insensitive to testosterone…
What happened during development inCongenital Adrenal Hyperplasia (CAH)?
What type of internal and external sex characteristics?
*Testosterone’s effect…
Heritable condition in which the fetus’s adrenal glands, NOT THE TESTES, release excess androgens.
INTERNAL GENITALIA: The extra testosterone in females, causes Wolffian system to not completely wither away (causing issues with reproduction) - AND gonads are set as ovaries because it developed before the testosterone was expressed by the adrenal glands.
Since there is NO testes and the Anti-Mullerian system is inactive- the Mullerian system develops by itself - PLUS a little dash of Testosterone
External Genitalia = Females can get ambiguous genitals (ex: micropenis, vagina and penis)
How are prenatal effects organized?
Prenatal effects of testosterone (no prenatal estrogen) organizes gonadal, internal, and external tissue to develop in certain ways.
What is happening during activation effects during puberty?
Activation effects - Not permanent, only see effects when the hormones are high (ex: females with higher estrogen levels will cause them to eat more; etc).
When does secondary sexual characteristics develop?
What are the secondary characteristics
During puberty.
\+Increased hairs \+Fat deposition patterns change; males = trunk, females = butt, thighs, breast \+Bone growth \+Males = Muscles \+Females = Menstrual
How old do females go into puberty now?
What are some explanations as to why females go into puberty earlier now than at 200 years ago?
+9 or 10 years old.
+Fat tissues - we are getting fatter earlier, so we can sustain pregnancies.
+RBST, estrogen hormones.
How is puberty started, neurochemically?
What do these chemicals do for females vs. males?
+Begins with the hypothalamus releasing the GnRH (gonadotropin-releasing hormone).
+Then the GnRH signals to the Anterior Pituitary gland to produce FSH (follicle-stimulating hormone) and LH (luteinizing hormone).
> Released in BOTH males and females.
+Females = begin menstrual cycles by stimulating ovaries (egg-making machines)
+Males = FSH increases sperm production.
What is FSH and LH’s role in males?
What does their initial production of testosterone do?
> FSH and LH increases gamete production (sperm) through increased production of Testosterone.
> Initial production of Testosterone promotes the development of male sec. sex. characteristics, such as muscle mass, external genitalia maturity, regulation of sperm production.
Why would males have a weaker immune system than females?
What does this say about the theory of sex attraction?
Testosterone weakens the immune system - It decreases the T and B cells, making males more vulnerable to disease.
The theory of sex attraction states that females are attracted to males with big muscles and strong jaws - They are signals of High Testosterone levels, and the advantages is that he probably has a kick-ass immune system.
