Chapter 12: Sex and Behavior Flashcards
1
Q
sexual behavior
A
neural circuitry of the brain that regulates reproductive behavior
2
Q
what guides reproductive behavior in many species?
A
pheromones
3
Q
reproductive behavior stages
A
- sexual attraction
- appetite behavior
- copulation
- postcopulatory behavior
4
Q
sexual attraction
A
brings males and females together
5
Q
sexual attraction can be synchronized with…
A
- physiological readiness to reproduce, indicated by odors reflecting estrogen levels in females
- learned associations, such as appearances
6
Q
appetite behavior
A
establish, maintain, or promote sexual interaction
7
Q
appetite behavior is _____
A
proceptive
- behavioral cue that a female displays to initiate or maintain sexual interaction with a male
8
Q
copulation
A
one or more intromissions in which a male penis is inserted with the female vagina
9
Q
what occurs after copulation?
A
male ejaculates sperm bearing semen into female
10
Q
what happens after first copulatory phase?
A
refractory phase: cannot have another orgasm
- lengthens with age
11
Q
coolidge effect
A
faster resumption of mating behavior, with a different partner
12
Q
what is estrus? and who shows it?
A
females who are willing to copulate are in estrus
estrus: sexually receptive
13
Q
postcopulatory behavior
A
the activity that occurs immediately after copulation between two animals
14
Q
copulatory lock
A
penis swells temporarily and cannot be withdrawn from female
15
Q
what does postcopulatory behaviors include?
A
parental behaviors to nurture offspring
- varies among species
16
Q
internal fertilization
A
fusion of gametes to produce a zygote inside the body
gametes: sperm in male and ova in females
17
Q
external fertilization
A
occurs outside body
- fishes and frogs release gametes into water
18
Q
ovulation
A
releasing eggs
19
Q
estrus
A
female displays proceptive behavior and adopts a posture called lordosis
20
Q
lordosis
A
allows intromission
21
Q
pair bonds
A
strong social relationship formed between two animals of the same species who live together before and after copulation
22
Q
sex steroids
A
important for mating behaviors
23
Q
castrated
A
testosterone is no longer produced, causes losing interest in mating
24
Q
activational effect
A
hormones briefly activate behavior
- can restore behavior
25
which estrogens are important for female proceptive behavior in rats?
estrogens produced in the beginning of the ovulatory cycle
26
progesterone
more increases in proceptive behavior and make females receptive
27
what do females without ovaries respond to?
combination of estrogen and progesterone treatments to make her proceptive and receptive
28
what brain structure is crucial for lordosis response through steroid actions?
ventromedial hypothalamus
29
what does the VMH do in the ovulatory cycle?
sends axons to periaqueductal gray in the midbrain >>> medullary reticular formation>> spinal cord >> reticulospinal tract
30
what does estrogen cause?
increase in dendritic trees of neurons in VMH and production of progesterone receptors, which contributes to lordosis through protein production
31
what brain structure coordinates male copulatory behavior?
medial preoptic area (mPOA)
32
what does the mPOA do in the reproductive cycle?
sends axons to ventral midbrain >>> basal ganglia >> brainstem nuclei >>> spinal cord
33
what does the paragigantocellular nucleus do for the male reproductive behavior?
inhibits erection response, then the mPOA signals counteract the inhibition
34
vomeronasal organ
detects pheromones that activate male arousal
35
where does the VMO send axons?
medial amygdala and turn to the mPOA
36
4 phases of response in human sexual behavior
1. excitement
2. plateau
3. orgasm
4. resolution
37
excitement
phallus becomes erect and there in increased blood flow to the vagina, leading to lubrication of fluids
38
orgasm
activation of variety of brain structures
39
what brain structures activate during an orgasm?
amygdala, cingulate cortex, nucleus accumbens, hippocampus
40
what are the activation of hypothalamic areas responsible for?
release of oxytocin, which occurs after an orgasm
41
sexual response in women
more selective in choosing someone for potential romance
42
sexual response in males
have absolute refractory phase following an orgasm
have stronger sex drives
43
sexual response in paralyzed women
can still have orgasms because the vagal nerve detects stimulation which leads to same activation of brain structures
44
example of pheromones affecting human reproductive behavior
menstrual cycles of women living together can synchronize
45
Major Histocompability Complex
group of immune-related genes with many alleles
46
women's preferences in MHC
prefer the smell of men with MHCs not too similar or dissimilar to their own
47
precocial
animals that are born in a relatively developed state and are able to survive with little maternal care
48
what are precocial animals born with?
well developed sensory and motor systems
example: horses
49
altricial
animals born in an undeveloped state and depend on maternal care
example: humans
50
who is involved in caring for their young in altricial animals?
males and females
51
rat mother behaviors
1. nest building
2. crouching over pups
3. retrieving pups
4. nursing
52
what prepares rat mothers for maternal behavior?
during pregnancy, exposure to hormones prepares her brain to display these behaviors immediately after giving birth
53
parabiotic
surgical preparation that joins two animals to share a single blood supply
54
example of parabiotic
nonpregnant female exposed to circulating hormones of a pregnant rat with display the same maternal behaviors
55
what brain structure is involved in maternal behaviors?
mPOA and periaqaeductal gray
56
sexual differentiation
physical process by which individuals develop male or females' body and behavior
57
sexual determination
genetic development even that decides if a fetus will be male or female
58
when does sexual determination begin?
in utero and continues into adulthood
59
what is the sex determining cell that carries either X or Y?
sperm
60
what always contains an X chromosome?
ovum
61
genes for male and female
XX = female
XY = male
62
indifferent gonads
undifferentiated gonads of the early vertebrate fetus, which develop into testes or ovaries in the first month
63
SRY gene
sex determining region on the Y chromosome, responsible for tests
- leads to domino effect in development of sex
64
what happens with an SRY gene on the Y chromosome?
an ovary forms
65
which gonad produces several hormones and which produces little hormone?
testes produce several hormone
ovaries produce little hormones
66
what directs sexual differentiation?
hormones secreted by gonads, mainly testes
67
exposure of testicular hormones
when exposed to testicular hormones, many tissues of the body begin developing masculine characters
- if cells are not exposed to testicular hormones, they develop feminine characters
68
what does differential exposure lead to?
differential exposure to sex steroids leads to differences in gene expression throughout body
69
what type of tissues do embryos have?
embryos have early tissues for both male and female structures
70
wolffian duct
duct system in the embryo that develops into male structures and mullerian duct shrinks
71
male structures
epididymis, vas deferens, seminal vesicles
72
mullerian ducts
duct system in the embryo that develops into female structures and part of the wolffian duct remains
73
female structures
fallopian tubes, uterus, vagina
74
what hormones from testes make the system masculine?
testosterone: promotes development of wolffian system
anti-mullerian hormone (AMH): induces reversal of the mullerian system
75
5a-reductase
enzyme that converts testosterone into more powerful dihydrotestosterone
- found in genital skin
76
dihydrotestosterone
potent androgen necessary to form genitalia
77
what happens without local DHT production?
genitalia becomes partially masculinized
78
what happens without any testosterone?
genitals become labia and clitoris
79
turner's syndrome
person only has one sex chromosome, a single X
80
what does a person with turners syndrome develop as?
female, without the SRY gene
has recognizable ovaries but underdeveloped and no masculinizing effects take place
81
congenital adrenal hyperplasia
result of female exposure to androgens before birth
82
how does CAH occur?
adrenal glads fail to produce corticosteroids and produce androgens >>> leads to intersex appearance
83
cloacal extrophy
genetic males born with testes but no penises
84
androgen insensitivity syndrome (AIS)
occurs in XY people whose androgen receptors do not produce testosterone
85
what occurs in people with AIS?
testes produce testosterone and AMH but no androgen receptors prevents the development of male features
86
what external genitalia do those with AIS have?
female genitals and develop as women
87
organizational effect
permanent alteration of nervous system, causing permanent change in behavior, resulting from action of a steroid hormone early in development
88
steroids
have organizational effect only when present during a sensitive period in early development
89
sensitive period
period during development in which an organism can be permanently altered by particular experience or treatment
90
sensitive period times
neonatal period and puberty
91
organizational hypothesis
explains sexual differentiation
92
aromatization hypothesis
says that testosterone enters the brain and is converted into estrogens
93
aromatization
enzyme aromatase converts testosterone to estradiol
94
A-fetoprotein
binds estrogen keeping it in the blood stream and prevents it from entering brain
- prevents aromatization and masculinization
- does not bind testosterone
95
sexual dimorphism
refers to sex differences in behavior or in structure
96
preoptic area
nucleus in POA is larger in male rats than female rats
97
what makes the POA in male rats larger?
testicular androgens
98
what does genital licking do for rats?
for males: greater licking masculinizes the developing system and important for SNB cell survival
for females: greater licking creates more attentive mothers in the future
99
what happens during puberty for males?
testosterone leads to development of small penis and body becomes masculinized
- become sexually interested in women and start behaving as men
100
guevedoces
boys who are raised as girls, but grow penis and then behave as men in adulthood
101
two classes of influence on sexual orientation
society's instruction on how should behave when grown up
biological factor
102
biological factor
varying levels of fetal androgens directs whether developing brains are attracted to females or males in adulthood
103
what is the conclusion on sexual orientation?
sexual orientation in both sexes is determined early in life
