NEUR533 - sex and the brain Flashcards
1
Q
A
2
Q
How many autosomes (first 22 pairs of chromosomes) are there in genetics?
A
44
3
Q
Is the X chromosome larger than Y?
A
Yes
4
Q
How many genes does the X and Y chromosomes contain?
A
X = 800 genes
Y = 50 genes
5
Q
Is the SRY gene on the X or Y chromosome?
A
Y
6
Q
What are autosomes?
A
- First 22 pairs of chromosomes
- Contain genes responsible for traits and characteristics
7
Q
A
8
Q
A
9
Q
What enzyme converts testosterone to oestradiol
A
Aromatase
10
Q
What are 2 gonadotropin hormones
A
- LH
- FSH
11
Q
What do the gonadotropic hormones LH and FSH do specifically in males?
A
- LH: stimulates testosterone
- FSH: aids sperm maturation
12
Q
What neurotransmitters relax smooth muscle in the penis and clitoris?
A
- ACh
- Vasoactive intestinal polypeptide (VIP)
- NO
13
Q
What is the main bonding hormones in males and females?
A
- Females; oxytocin
Males - vasopressin
Oxytocin is also both - especially with intercourse
14
Q
What does PAG stand for in the brain?
A
Periaqueductal Grey matter
15
Q
Look into COX inhibitors and the sexual brain
A
16
Q
Is vasopressin receptors and increased dendritic spine density associated with paternal motivation and behaviour? Y/N
A
Yes
17
Q
How many chromosomes in total is the DNA organised into?
A
46
23 maternal
23 paternal
18
Q
Where is LH and FSH hormones released?
A
anterior pituitary gland
19
Q
What hormone does the hypothalamus secrete to release LH and FSH from the anterior pituitary gland?
A
Gonadotropin-releasing hormone
20
Q
Define polygyny and polyandry
A
polygyny: males mates with many females
polyandry: females mate with many men
21
Q
Whats another term for vasopressin?
A
Antidiuretic hormone ADH
22
Q
What is the name of the vole that exhibits solid family values?
A
Prairie vole
23
Q
What is the clearest dimorphic nuclei found to be twice as large in men than women?
A
INAH-3
INAH-3 in homosexual men is similar in size to that of women.
24
Q
For example, certain metabolites (breakdown products) of progesterone bind to the inhibitory GABAA receptor and poten- tiate the amount of chloride current activated by GABA. The effects of these progesterone metabolites are quite similar to the sedative and anticonvul- sant effects of the benzodiazepine class of drugs
A
25
Does leptin suppress or increase appetite?
suppress
26
Other research has found the anterior commissure and suprachiasmatic nucleus to be larger in male homosexuals than in male heterosexuals.
One study reported that the bed nucleus of the stria terminalis is larger in men than women and that male-to-female transsexuals have a nucleus comparable in size to females.
27
DNA is organized into____ chromosomes
46
23 from the father and 23 from the mother
28
it is usually stated that there are___ autosomes (22 pairs of matching chromosomes) and two sex chromosomes.
44
29
any defect in the single X chromosome of a male can lead to a developmental defect. Such a defect is called an_________ disease, and there are many.
X-linked
30
Sex-determining region of the Y chromosome (SRY), codes for a protein called ____ _______ ______
testis-determining factor (TDF).
31
Turner syndrome is a partial or complete absence of one___ chromosome in a female (XO genotype), affecting about one in 2500 female births.
X
32
In about one in 1000 male births, there is an extra X chromosome; this defect is known as____________ syndrome. These XXY individuals are male because of the presence of the SRY gene on the Y chromosome.
Klinefelter
33
Steroids are fatty and can easily pass through cell membranes and bind to receptors within the cytoplasm, giving them direct access to the________ and______ expression.
nucleus
gene
34
What hormone does the hypothalamus secrete for sex hormone production in the ovaries or testes?
Gonadotrophin releasing hormone
35
What does GnRH stimulate?
The anterior pituitary gland
36
In the__________ cycle of non-primate mammals, such as rats and mice, the LUTEAL phase is much shorter.
estrous
37
full sexual response cycle consists of________ followed by plateau, orgasm, and resolution phases.
arousal
38
The external genitals are densely innervated by_______________, particularly within the clitoris and the glans of the penis
mechanoreceptors
39
The best evidence that engorgement can be generated by a simple spinal reflex is that most men who have suffered a complete transection of the spinal cord at the thoracic or lumbar level can nevertheless experience an erection when their penis is mechanically stimulated.
40
Axons from mechanoreceptors in the penis and clitoris collect in the_______ roots of the sacral spinal cord. They then send branches into the _____ ____ of the cord, and into the _____ ________, through which they project toward the brain.
dorsal
dorsal horns
dorsal columns
41
In order to keep the organs sliding easily during copulation throughout the plateau phase, parasym- pathetic activity also stimulates the secretion of lubricating fluids from the woman’s vaginal wall and from the man’s____________ gland.
bulbo-urethral
42
Completing the sexual response cycle requires activity from the ________ division of the ANS
sympa- thetic
43
As sensory axons, particularly from the penis or clitoris, become highly active, they, together with activity descending from the brain, excite sympathetic neurons in the______ and _______ segments of the spinal cord
thoracic
lumbar
44
In men, the sympathetic efferent axons then trigger the process of__________: Muscular contractions move sperm from storage sites near the testes through two tubes called the vas deferens, combine the sperm with fluids produced by various glands, and propel the resulting mixture (called semen) into the urethra.
emission
45
In the surgical treatment of epilepsy, electrical stimulation of the _____ _______ lobe or the basal forebrain has been reported to cause sexual arousal in some patients.
medial temporal
46
KNOW AND DRAW OUT ...
47
What do the parasympathetic pathways innovate from the sacral segments of the spinal cord to the sex organs?
Labia, clitoris
and penis
48
What do the sympathetic pathways innovate from the LUMBAR segments of the spinal cord to the sex organs?
Uterus, Vagina
Prostate gland
49
Where are oxytocin and vasopressin synthesised and released?
Synthesised - paraventricular nuclei of the hypothalamus
Released - capillaries directly into posterior pituitary gland
50
vasopressin is synthesized in the supraoptic and_________ nuclei of the hypothalamus.
paraventricular
51
Several brain areas, including the ________ _______ cortex, the caudate nucleus, and the striatum, are more activated by one’s child and partner than by pictures of unrelated people.
anterior cingulate
52
The DNA sequences that code vasopressin receptors in montane and prairie voles are nearly identical, but the monogamous prairie voles have a DNA sequence adjacent to the gene that encodes the _____ vasopressin subtype (called a gene variant).
V1aR
53
Sexual dimorphism in rats.
54
The aptly named sexually dimorphic nucleus (SDN) is five to eight times larger in______ than in females
males
55
There are four clusters of neurons called the _____ _____ __ __ ________ ___________
interstitial nuclei of the anterior hypothalamus (INAH).
In different studies INAH-1, INAH-2, and INAH-3 have all been reported to be larger in men than women.
56
The direct and indirect effects of ste- roids on neurons
57
Steroids can act quickly _______________- to alter membrane excitability, sensitivity to neurotrans- mitters, or neurotransmitter release.
(within seconds or less)
58
Steroid Receptors with bound steroid can either promote or inhibit the transcription of specific genes in the nucleus, a process that can take _______ ___ _______.
minutes to hours
59
the ability of testosterone to alter very young genitals and brain circuitry, leading to distinctly male genitals and masculine behaviors later in life, can be thought of as the ____________ effects of the hormone. The hormone organizes the perinatal tissues in irreversible ways that allow it to generate male functions after sexual maturity has been reached
organizational
60
For a mature animal to express sexual behaviors fully, however, it is often necessary for steroid hormones to circulate again during periods of sexual activity, providing ___________ effects on the nervous system. Thus, for example, testosterone levels might surge in the body of a male songbird in the spring, activating changes in certain parts of his brain that are essential for normal reproductive behavior
activational
61
The rise in testosterone that occurs pre-natally actually leads to an______ in estrogen, which binds to estradiol receptors, thereby triggering___________ of the developing nervous system.
increase
masculinization
62
63
Some humans also experience mismatches between their chromosomes and sex hormones. For example, genetic males (XY) who carry a defective androgen receptor gene may have profound androgen insensitivity. The androgen receptor gene is on the __chromosome; males thus have only one copy of it, and males with the defective gene cannot produce functioning androgen receptors.
X
64
If the____ gene is absent in a male fly, male courtship behaviors are significantly reduced or nonexistent. Conversely, females made to express fru exhibit male courtship behaviors and resist courtship by males.
fru
65
testosterone levels rise in_________ of a sexual act or even while fantasizing about it.
anticipation
66
__________ enhances the influence of dopamine released by neurons projecting from the ventral tegmental area (VTA) into the nucleus accum- bens (NA)
Lactation
67
Estradiol may also alter hippocampal function by decreasing synaptic inhibition. Estradiol causes some inhibitory cells to produce less GABA, their neurotransmitter, and therefore synaptic inhibition becomes less effective.
In rats, the hippocampus is particularly important for spatial memory and navigational skills, and several studies demonstrate that estradiol enhances such forms of memory formation.
68
It is interesting to note that the memory benefit associated with the estradiol disappears if the estrogen is given__ hours after training. Evidently, estrogens can facilitate memory, but they must be present near in time to the learning experience.
2
69
there is no evidence that sexual orientation is related to activational effects of hormones in adults. For example, administering androgens or estrogens to adults, or removing the gonads, has no effect on sexual orientation. As an alternative, perhaps homosexual and het- erosexual brains are structurally different due to_____________ effects.
organizational
70
We saw earlier that in animals, there are sex differences in the ante- rior hypothalamus. In rats, the ______ ______ _______ in the preoptic area of the anterior hypothalamus is much larger in males than females.
SDN (sexually dimorphic nucleus)
After a surgical lesion to this brain area, male rats spend more time with sexually active males than with sexually receptive females, a reversal of their preference before surgery.
71
In humans, the ______ nucleus (one of the interstitial nuclei of the anterior hypothalamus) is about twice as large in men as in women, a difference that may be related to sexually dimorphic behaviour.
Some studies of the INAH suggest that there are differences between homosexual and heterosexual brains that might be related to sexual orientation.
INAH-3
INAH-3 in gay men is only half the size of the nucleus in straight men
= smaller INAH-3 = preference for men
72
Other research has found the anterior commissure and suprachiasmatic nucleus to be larger in male homosexuals than in male heterosexuals. One study reported that the bed nucleus of the stria terminalis is larger in men than women and that male-to-female transsexuals have a nucleus com- parable in size to females. Collectively, these studies offer the intriguing prospect that complex aspects of human sexual behavior may ultimately be linked to distinct brain organization.
73
