102 terms

Animal Biology Test 4


Terms in this set (...)

paired organs in females
produce eggs and secrete sex hormone
women are born with all the eggs they'll ever have
onset of first menstrual cycle
ovarian follicles
oocyte is surrounded by follicular cells
secrete estrogen
in varying stages of development
as development proceeds, number of follicular cells increases
space between oocyte and follicular cells form
release of egg from ovary
mature follicle ruptures through ovary wall
egg is released into pelvic cavity
hormone that brings about primary and secondary sex characteristics
primary sex characteristic
development and maintenance of female reproductive organs
secondary sex characteristics
thicker layer of fat under skin than men
corpus luteum
endocrine structure that develops from remnants of ovarian follicle after ovulation
secretes progesterone
promotes gestation
increases secretions of uterine glands
decreases contractions of smooth muscle in the uterus
uterine tubes
not physically attached
lies near the ovaries
equipped with finger-like projections that are lined with cilia
fertilization occurs here
finger-like projections at the end of the uterine tubes
fertilized egg implants here
attachment of the fertilized egg to the wall of the uterus
ectopic pregnancy
implantation of fertilized egg outside the uterus
tubal pregnancy
ectopic pregnancy in the uterine tube
life threatening
most common ectopic pregnancy
lining of the uterus
implantation occurs here
2 regions: functional layer, basal layer
functional layer
inner layer of endometrium
detaches during menstrual cycle and sloughs off
tissue and blood loss
basal layer
outer layer of endometrium
remains intact during period
smooth muscle layer of uterus
region of uterus that projects into vagina
receptacle for penis
birth canal
female external genitalia
mons pubis
labia majora
labia minora
labia majora
female organ homologous to the scrotum
female organ homologous to the penis
follicle stimulating hormone
hormone that targets the anterior pituitary lobe
follicle development and estrogen secretion
luteinizing hormone
hormone that targets the anterior pituitary lobe
progesterone secretion by corpus luteum
ovarian cycle
all the changes that occur in the ovaries over a 28 day period
due to fluctuating blood levels of FSH and LH
happens in 3 phases: follicular, ovulation, luteal
follicular phase
day 1-13 of ovarian cycle
high FSH
development of ovarian follicles and estrogen secretion by follicles
day 14 of ovarian cycle
LH surge
release of egg by the ovary
luteal phase
day 15-28 of ovarian cycle
high LH
progesterone secretion by corpus luteum
uterine cycle
changes in the uterus over the same 28 day period as the ovarian cycle
due to fluctuating levels of estrogen and progesterone
3 phases: menstrual, proliferative, secretory
menstrual cycle
day 1-5 of the uterine cycle
low estrogen
estrogen is too low to maintain endometrium
functional layer of endometrium sloughs away
proliferative phase
day 6-14 of the uterine cycle
increase in estrogen
promotes repair of functional layer of endometrium
secretory phase
day 14-28 of the uterine cycle
rising progesterone levels
increases output of uterine glands
source of nutrition for the fertilized egg
inhibits contraction of myometrium
prevents fertilized egg from expelling out of the body
units of instruction for producing or influencing a trait
different forms of the same gene
actual genes present
both alleles code for the same form of the trait
the alleles are different forms of the trait
observable trait
in the nucleus in eukaryotes
DNA and protein
before cell divides, this condenses
condensed chromatin
not involved in determining sex
humans: pairs 1-22
sex chromosomes
X and Y chromosomes
involved in determining sex
somatic cells
body cells
46 chromosomes
44 autosomes
2 sex chromosomes
sex cells
egg, sperm
23 chromosomes
22 autosomes
1 sex chromosome
picture of all chromosomes in one cell
number, size, and structure are analyzed
often blood cells
created when cells are dividing
female sex chromosomes
male sex chromosomes
based on Y sex chromosome
codes for testis determining factor
testis determining factor
early in development, gonads are neither male nor female
this hormone targets the early gonads and the testes develop
sex linked traits
traits by genes on sex chromosomes
X-linked or Y-linked
sex linked traits that can only be expressed by males
most sex linked traits
genes on the X sex chromosome
ex.- colorblind, faulty tooth enamel
chromosomal nondisjunction
failure of the chromosomes to be separated properly during gamete formation
errors made during spermatogenesis or oogenesis
eggs and sperm form with abnormal numbers of chromosomes
offspring inherit 1 additional chromosome or are missing 1 chromosome
offspring are missing one chromosome compared to parental number
offspring have one extra chromosome compared to parental number
turner syndrome
involves sex chromosomes
missing second sex chromosome
genotypic females
shorter life expectancy
learning disabilities
widely spaced nipples
"webbed neck"
down syndrome
trisomy 21
extra 21st chromosome
involves autosomes
mild to severe mental impairment
shorter life expectancy
klinefelter syndrome
involves sex chromosomes
genotypic males
extra X sex chromosome
testes are 1/3 normal size
learning disabilities
breast development
jacob's syndrome
involves sex chromosomes
genotypic males
extra Y sex chromosome
may have learning disabilities
most function normally in society
triple X syndrome
involves sex chromosomes
extra X sex chromosome
may have menstrual problems
zona pellucida
acellular layer that surrounds eggs
corona radiata
thin layer of follicular cells that surrounds the zona pellucida
union of a sperm and egg
forms a zygote
fertilized egg
early cell divisions
cells increase in number but not in size
cellular division with increase in number and in size
the embryo begins to take shape
tissues and organs emerge
unspecialized cells develop into cells with special structures and functions
extraembryonic membranes
yolk sac
fetal contribution to the placenta
gives rise to the bladder and the blood vessels of the umbilical cord that carry blood to and from the uterus
yolk sac
contains many blood vessels and is where blood cells first form
secretes amniotic fluid that cushions and protects the embryo
surrounds the embryo
stages of development
pre-embryonic development
embryonic development
fetal development
development after birth
pre-embryonic development
1st week of development after fertilization
after fertilization, zygote divides repeatedly as it passes down the oviduct to the uterus
the early appearance of the chorion emphasizes the complete dependence of the developing embryo on this extraembryonic membrane
compact ball of embryonic cells
morula develops into this
inner cell mass, trophoblast
blastocyst becomes organized into these 2 things
inner cell mass
eventually becomes the embryo
eventually becomes the chorion
embryonic development
2nd week after fertilization until the end of the 2nd month
fetal development
the 3rd through the 9th months of development
development after birth
stages of life including infancy, childhood, adolescence, and adulthood
human chorionic gonadotropin
secreted by the blastocyst that maintains the corpus luteum and emndometrium
basis for pregnancy test
week 3
nervous system begins to develop
development of the heart begins
week 4
embryo is slightly larger than the height of the print in your book
umbilical cord forms
limb buds form
week 5
head enlarges
eyes, ears, and nose become prominent
weeks 6-8
embryo begins to look like a human being
reflex actions occur
all organ systems have been established
38 mm by the end of this period and weight is about the same as an aspirin tablet
months 3-4
hair develops
the head slows in growth so that the body size can catch up
cartilage begins to be replaced by bone
able to distinguish male from female
can hear heartbeat with a stethoscope
by the end of this period, fetus is about 6 inches and 6 ounces
months 5-7
movement can be felt by mother
fetus is in fetal position
eyelids are fully open
about 12 inches and 3 pounds
months 8-9
gains about 1 pound per week
fetus rotates so that head is toward the cervix
about 7.5 pounds and 20.5 inches
characterized by uterine contractions that occur every 15-20 minutes and last for at least 40 seconds each
occurs in 3 stages
stage 1 of birth
effacement occurs in which the cervical canal slowly disappears and the baby's head acts as a wedge to cause cervical dilation
stage 2 of birth
uterine contractions every 1-2 minutes, lasting for a minute each
an incision is made to the opening to help the baby as its head reaches the exterior
once the baby is born, the umbilical cord is cut and tied
stage 3 of birth
the afterbirth is delivered, usually about 15 minutes after the birth of the baby
giving birth to many offspring at one time
only giving birth to one offspring at a time
monozygotic twins
identical twins
twins derived from 1 zygote
identical genomes
1 egg is fertilized
blastomeres become separated or inner cell mass splits
may separate early and have separate placentas
2/3 share a placenta
dizygotic twins
fraternal twins
twins develop from 2 zygotes
2 eggs fertilized by 2 different sperm
not genetically identical