puberty and adolescence
Terms in this set (90)
early sex maturation, before puberty
-usually between 6 - 8 years
what happens to the adrenal cortex during adrenarche?
the adrenal cortex forms a new layer called the ZONA RETICULARIS
formed during adrenarche, in the adrenal cortex
-secretes weak androgens (DHEA, DHEAS)
the juvenile stage starts around age of 7 when the adrenal cortex secretes weak androgens
what are the result of juvenile stage?
-the brain increases in SA - cognitive development
-less dependent on parents
-height growth rate is increased
biological change from sexually immature to sexually mature
the stage between the start of pubertal changes until sexual maturation
(from adrenarche to puberty)
period between puberty until social adulthood
upon completion of puberty, how does the body weight differ between males and females?
females body weight has a higher percentage of fat than males
is the classification of pubertal changes
-jphysical characteristics that change in a predicted manner
it allows physicians to see where the child is a long puberty chronology
which physical traits are examine for females when looking for tanner stages?
the breast and the pubic hair
which traits are examed for males when looking for tanner stages?
penis, testis, and pubic hair
stage 1 for female breast development
stage 2 for female breast development
breast and nipple elevate and the areola increases in size
stage 3 in female breast development
breast and areola enlarge, no contour separation
stage 4 in female breat development
the nipple forms a secondary mound which produces a contour seperation
stage 5 in female breast development
nipple projects and areola becomes part of general breast contour
pubic hair tanner stages in females and males
the hair gradually grows
tanner stages in testes length
the testes grow from less than 2.5 cm to more than 4.5 cm
female- 9 years
avg. age to start showing early pubertal changes like:
-fat deposition increased
-accelerated skeletal growth
female- 10 years
avg. age for sex characteristics to appear
-early breast development
-widening of the pelvis
-fat deposition in breast and hips
female - 11 years
ovaries and sex accessory ducts grow
female - 12 years
menarche - first period
female -13 years
skeletal growth rate declines
sweat and sebaceous skin glands develop
what is the avg, age for menarche?
what is the avg. age for females voice to deepen slightly?
when do females reach adult height?
what causes females to reach adult height?
the high amount of estrogen in the body stops bone growth
when does the pelvis reach full final size?
at least 4 years after menarche
-it is the last part of the bones to mature
is maturation of the pelvis bone connected to menarchy? when do females reach full pelvic maturation?
the pelvic bone growth seems to be independent of menarchy
-it reaches full growth @ avg. 17-18 years
precocious puberty in females
-breast development and pubic hair develop BEFORE age 7
delayed puberty in females
no breast or skeletal growth by age 14
additional causes of primary amenorrhea
male - 9 years
avg. age for males to show early pubertal changes
-leydig cells activate and begin secreting androgens
male 10 years
increase subcutaneous fat deposition
males- 11 years
skeletal growth spurt
increase in penis and scrotum size
increase in spontaneous erections
growth in seminal vesicles and prostate gland
male - 12 years
pubic hair development
male - 13 years
hair appears on axilla and upper lip
voice deepens because the larynx grows
male - 14 years
spermachy - first fertile ejaculation
male - 15 years
sweat and sebaceous glands to develop
male - 16 years
accelerated muscle growth
broadening of shoulders
male - 17 years
avg. age to reach adult height
when do males brain reach final size?
precocious puberty in males
sexual development before the age of 9
delayed puberty in males
no testicular growth has happened by age 14
no skeletal growth spurt by age 18
are leydig cells present at birth? are they active?
they are present at birth but they are inactive
-active in the fetus, and reactivate at age 9
when does spermatogenesis begin?
avg. age 9 - the beginning of pubertal changes
testes fail to descend into scrotum by birht
what are the consequences to cryptochordism still at age 10?
spermatogenesis cannot begin
causes infertility because of temp
which hormones are responsible for bone growth in both sexes?
growth hormone (GH) and androgens
thyroid hormones at puberty in both sexes
thyroid hormone increases at puberty
supports body growth
rise in metabolic rate
where is estradiol made?
from the follicle in the ovary
where is estrone made?
made from body fat
congenital adrenal hyperplasia
disease due to lack of an enzyme needed by the adrenal gland to make cortisol and aldosterone
-without the enzyme, more androgens are made which causes male characteristics -> for males its fine -> for females it could enlarge the clitoris
in males, which hormones cause the beginning of spermatogenesis and testosterone secretion?
LH and FSH
do males have estrogen during puberty?
yes, most likely made by sertoli cells
- some males have the nipple form a lump
-estrogen levels rise slightly in before and during puberty
Acne is caused by -
androgens cause the skin to make sebaceous glands that can become clogged and infected with bacterial = acne
how does the hypothalums in children compare to that of adults in terms of negative feeback?
childrens hypothalamus is 6-15 times more sensitive to steroidal negative feedback
is there positive feedback on GnRH in children?
how does stress affect GnIH?
stress can cause an increase of GnIH in the hypothalamus
-could be why females dont ovulate when stressed
-stress can also cause females to have delayed menarchy
is the GnRH pulse generator activated in children?
no the pulse generator is inhibited
-it is speculated that this inhibition is due to GnIH, which is present in childhood and most likely drops before puberty
at puberty do both female and males go through positive feedback of GnRH?
No only females
what causes there to be a positive feedback of GnRH?
the maturation of the hypothalamic GnRH surge center so it can make FSH & LH
Also the ability of the pituitary to store adequante amounts of gonadotropins
what happens to the level of melatonin before puberty?
the level of melatonin lowers before puberty
-melatonin can inhibit reproductive function
light/darkness and menarchy
in the darkness -> more melatonin
in constant light -> less melatonin -> earlier onset of menarche
how does kisspeptin regulate gonadotropins?
kisspeptin is a hormone that triggers the release of GnRH which increases the production of LH and FSH
kisspeptin binds into the which receptor?
how does kisspeptin affect seasonal reproduction?
sex drive appears to be high when in favorable environments
-this seems to be regulated by kisspeptin
is a protein produced in fat cells
what is the level of leptin in the blood before the onset of puberty in females and males?
leptin increases before puberty
-it has a PERMISSIVE EFFECT
-increases the rate of GnRH pulses
since leptin is made in fat cells, how does obesity affect puberty?
obese females will have higher levels of leptin and will enter puberty earlier
how has the age of menarche change over the last 100 years?
it has decreased by 2 years
what could be some of the reasons the age of menarche is decreasing globally?
improved nutrition and access to food
less physical activity and more weight gain
what does leptin signal to GnRH neurons?
what does insulin signal to GnRH neurons?
metabolic fuel availability
what does ghrelin signal to GnRH neurons?
indicates an empty digestive tract
fetal and childhood nutrition can determine age of menarchy
if the nutritional stress is in fetal stage then the age of menarchy will be earlier
if the nutritional stress in later in childhood, then age of menarchy will be later
light at birth and heavy at 8 years
have the earliest menarchy
heavy at birth and light at 8 years
have the latest menarchy
8 years old - low weight and and nutritionally deficient
the body will delay menarchy
8 years old - heavy weight and overabundance of nutrition
malnutrition and menarchy
if malnutritioned, then there is low fat -> delay menarchy
what percentage of fat is needed for sexual maturation to begin?
what effect does adoption have on menarchy?
girls that are adopted from other countries, experience precocious menarchy
-could be due to psychosocial stress they faced in early childhood
girls raised in a conflict household will or raised without a father -
-reach menarchy 5 months earlier
- pass through pubertal stages more quickly
- have children at an earlier age
- spent less effort and time with their children
- formed less stable bonds with their partners
female children who experience coercive and negative family relationships will have -
an accelerated sexual maturation
female children from homes with warm and nurturin environments will -
go into menarchy later
-the body thinks that since it is stable environment, sexual maturation can occur later when the girl is older and better equited for sexual maturation
which gene influences breakdown of testosterone
what is the result of having a low ratio of testosterone:estrogen?
there will be an earlier initiation of sexual development