126 terms

Animal Biology Lecture Test 4- Gay Williamson


Terms in this set (...)

How many eggs are females born with?
all the eggs they'll ever have
the release of eggs by ovary; release of egg into the pelvic cavity
paired organs, produce eggs and secrete female sex hormones, contain ovarian follicles, about 400,000 ova per ovary at menarche
ovarian follicles
composed of an oocyte surrounded by follicular cells, follicles secrete estrogen, follicles are in varying stages of development
as follicular development proceeds...
the number of follicular cells increases
as the follicles mature...
a space forms between the oocyte and the follicle cells and fills with a fluid
fluid pressure within follicle leads to...
the follicle rupturing and egg releases into pelvic cavity
release of egg by follicle from ovary, egg released into pelvic cavity
when a follicle ruptures...
it ruptures through the wall of the ovary
required development and maintenance of female reproductive organs
females have thicker layer of adipose tissue (fat) deposited beneath their skin; softer touch to skin than males
corpus luteum
yellow, endocrine structure that develops from the remnants of the ovarian follicle after ovulation, secretes progesterone
promote gestation, increase secretions of uterine glands, increase contraction of uterine smooth muscle
uterine tubes
oviducts/fallopian tubes, not physically attached to the ovaries, sister of fertilization
region that lies near the ovary and is equipped with finger like projections , lined by ciliated cells that generate a current and draw the egg into the uterine tube
"womb", organ in which implantation of fertilized egg occurs
attachment of the fertilized egg to the wall of the uterus at the beginning of a pregnancy
ectopic pregnancy
implantation of fertilized egg outside of the uterus
tubal pregnancy
ectopic pregnancy in the uterine tube, most common site of ectopic pregnancy, life threatening for mother
lining of the uterus, implantation occurs in this layer
functional layer
functionalis, inner layer, detaches during the menstrual cycles, tissue and blood loss
basal layer
basalis, outer layer, remains in tact during menstrual cycle
smooth muscle layer of the uterus, incredibly thick smooth muscle layer
region of the uterus that projects into the vagina, lining will not be sloughed away during menstrual cycle
receptacle for penis, serves as the birth canal
female external genitalia
labia majora
homologous to scrotum in males (similar origin)
homologous to penis
blood levels of FSH, LH, estrogen, and progesterone....
fluctuate widely over a 28 day period
gonadotropin releasing hormone (GnRH)
secreted by the hypothalamus, FSH and LH secretion by pituitary
follicle stimulating hormone (FSH)
secreted by the anterior pituitary, initiates follicle development and estrogen secretion
luteinizing hormone (LH)
secreted by the anterior pituitary, progesterone secretion by corpus luteum
ovarian cycle
changes in ovary over 28 day cycle, occurs due to change in blood levels of FSH and LH by pituitary
Days 1-13, Follicular Phase
high blood levels of FSH, FSH stimulating follicle development and estrogen secretion
Day 14, Ovulation
LH surge, release of egg by ovary
Day 15-28, Luteal
high blood levels of LH, progesterone secretion by corpus luteum
uterine cycle
refers to all the changes occurring in the uterus over 28 day cycle, these changes are due to fluctuating blood levels of estrogen and progesterone
Day 1-5, Menstrual
low blood levels of estrogen, blood estrogen levels are too low to maintain endometrium, stratum functionalis detaches and sloughs away
Day 6-13, Proliferate
rising blood estrogen levels; as blood estrogen levels increase, functionalis proliferates and repairs itself
Day 14-18, Secretory
progesterone, uterine glands increase secretory activity, myometrium is inhibited from contracting
How many genes do humans have?
about 25,000
Each somatic cell contains....
about 2 meters of DNA
Enough DNA to go from the Earth to the Sun and back how many times?
units of instruction for producing or influencing a trait
-you inherit 2 genes for each trait:
one gene from father in sperm, one gene from mother in egg
different forms of a gene for a specific trait
ex. trait: eye color, so alleles: blue, green, brown, etc.
the actual genes present
homozygous (bb)
if both genes (alleles) code for same form of a trait
heterozygous (Bb)
if both genes (alleles) code for different form of a trait
the observable trait
located in the nucleus of eukaryotic cells, composed of DNA and protein, thread-like, before a cell condenses the chromatin condenses
condensed chromatin
chromosomes not involved in sex determination
-in humans: 1-22 chromosome pairs
sex chromosomes
involved in sex determination, X and Y chromosomes in humans
the nucleus of each somatic (body) cell
contains 46 chromosomes:
44 autosomes and 2 sex chromosomes
homologous pairs or homologs
chromosomes are present in pairs
- 1 inherited from mother in egg, other from father in sperm
the nucleus of the sex cell (egg or sperm)
contains 22 total chromosomes:
22 autosomes and 1 sex chromosome
visual representation of chromosomes within a cell; number of chromosomes, size and structure analyzed; blood cells often used
karyotype analysis
done on cells when their dividing chromosomes are clearly visible then
2 types of sex chromosomes
X , Y
SRY gene
located on Y sex chromosome; codes for testis determining factor
Testis Determining Factor (TDF)
Early in development, the gonads are neither testes nor ovaries. They are sexually indifferent. TDF targets the early gonads and in response testes develop.
sex-linked traits
traits coded by genes on the sex chromosomes, designated as X-linked or Y-linked
Y-linked traits
genes on Y chromosome concerned with gender determination, only expressed in males
X-linked traits
traits coded by genes on the X sex chromosome, most sex linked traits are X-linked
capital letter
dominant gene
lower case letter
recessive gene
Examples of X-linked Traits
1. colorblindness
2. duchene muscular dystrophy
3. fragile X syndrome
4. production of faulty tooth enamel
normal development depends on...
the presence of exactly 2 of each type (autosome and sex chromosomes) in somatic cells
abnormal #'s of chromosomes...
lead to developmental abnormalities
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 #s of chromosomes
offspring inherit one additional chromosome or are missing one chromosome
offspring missing one chromosome compared to parental number
offspring have one extra chromosome compared to parental number
Turner Syndrome
involves sex chromosomes
sex chromosome X,O
O represents missing sex chromosomes
Genotypic females
shorter life expectancy
learning disabilities
widely spaced nipples
"webbed" neck
Down Syndrome
trisomy 21
extra copy of chromosome #21
involves autosomes
mild to severe mental impairment
shorter life expectancy
heart problems
poor muscle tone
Klinefelter Syndrome
involves sex chromosomes
genotypic males
sex chromosomes: XXY
extra X sex chromosomes
sterile: teses 1/3 of normal size
learning disabilities
breast development
Jacob's Syndrome
Involves sex chromosomes
genotypic males
sex chromosomes: XYY
extra Y sex chromosomes
may have learning disability
most function normally in society
Triple X Syndrome
involves sex chromosome
sex chromosomes: XXX
extra X chromosome
may have menstrual problems
offspring have multiple copies of all parental chromosomes
ex. humans: 69, 92, 115, etc.
In humans: not compatible with life
In plants: common
Polyploid plants are sterile and have no seeds.
They produce seedless fruits (watermelon, grapes)
-union of the egg and sperm
-forms a single cell called the zygote from which we all develop
-occurs 12-14 hours after ovulation
zona pellucida
the acellular membrane that surrounds the egg plasma membrane
corona radiata
a thin layer of follicular cells that are attached to the zone pellucida
Events occurring during ferlization
1. several sperm penetrate the corona radiate
2. acrosomal enzymes digest a portion of the zona pellucida
3. sperm binds to and fuses with the egg's plasma membrane
4. sperm nucleus enters egg
5. cortical granules release enzymes and zona pellucida becomes the fertilization membrane
6. sperm and egg nuclei fuse
early cell divisions resulting in an increase in the number of cells but not the size of the organism
-30 hrs to day 3 after ovulation
cells undergo division as well as increase in size
embryo begins to take shape as cells migrate
cells take on specific structure and functions
(nervous system is first visible system)
pre-embryonic development
first week following fertilization
-zygote divides repeatedly as it passes from oviduct to uterus
compact ball of embryonic cells
-forms 3rd to 4th day after ovulation
hollow ball of cells; 5th day through 2nd week of development; embeds in uterus between days 6&7; forms trophoblast and inner cell mass
inner cell mass
embryo develops from this region
becomes the chorion
secretes amniotic fluid that cushions and protects the embryo
yolk sac
blood cells first form here; very little yolk is present in human's
forms portion of the placenta
organ that provides embryo with nourishment and gets rid of wastes
gives rise to the bladder and the blood vessels of the umbilical cord that carries blood to and from the fetus
embryonic period
second week through the end of the second month
formation of the 3 primary germ layers: ectoderm, mesoderm, and endoderm
epidermis, nervous system
skeletion, muscles, debris, cardiovascular system, reproductive system, urinary system
epithelial lining of the digestive, respiratory, and urinary bladder
fetal period
beginning of month three extending through month nine, period of rapid growth
true labor is characterized by uterine contractions that occur every 15-20 minutes and last for at least 40 seconds each
stage 1: effacement
cervix shortens (moves toward head of baby), softens, and becomes thinner
stage 2: episiotomy
incision made in the perineum to enlarge the passageway for the baby to come through
-uterine contractions occur every 1-2 minutes, lasting for 1 minute each
-once baby is born, umbilical cord is cut and tied
stage 3
delivery of the placenta (afterbirth); usually about 15 minutes after the birth of the baby
identical (monozygotic) twins
one egg is fertilized; genetically identical; result from separation of blastomeres or splitting of the inner cell mass
fraternal (dizygotic) twins
two eggs are fertilized by two different sperm; each embryo has its own amnion and placenta; frequency increases with age of mother; "runs" in families
second week
implantation occurs; amnion and yolk sac appear; embryo has tissues; placenta begins to form
third week
nervous system begins to develop; allantois and blood vessels are present; placenta is well formed
fourth week
limb buds form; heart is noticeable and beating; nervous system is prominent; embryo has a tail; other systems form
third month
gender can be distinguished by ultrasound; fingernails appear
seventh month
testes descend into scrotum; eyes are open; fetus is about 300 mm (12 in) long and weighs about 1,350 grams (3 lbs)
ninth month
fetus is ready for birth; it is about 530 mm (20.5 in) long and weighs about 3,400 grams (7.5 lb.)
skin cancer
most common form of cancer in the US
> 3.5 new cases annually
more than cancers of the breast, prostate, lung and colon combined
basal cell carcinoma
-most common (2.8 million/year US)
-open sore that bleeds, oozes, or crusts
-heals but then bleeds again
-rarely fatal
squamous cell carcinoma
-2nd most common form
-rarely fatal
-persitent thick, rough, scaly, patch
-bleeds if bumped
-often look like warts
-may appear as open sores
-raised border
-crusted surface
-scaly red patch
-most dangerous type of skin cancer
-accounts for 4% of skin cancers
-77% of skin cancer deaths
-about 100,000 cases diagnosed each year
-about 90% attributed to UV radiation
A-Asymmetry: two halves do not match
B-Border: border uneven
C-Color: variety of colors black or blue
D-Diameter: usually large
E-Evolving: any changes
use of tanning beds
-2.5x more likely to develop squamous cell carcinoma
-1.5x more likely to develop basal cell carcinoma
1st exposure to tanning beds in youth
increases melanoma risk by 75%
-penetrates clouds and glass
-penetrates skin more deeply than UVB
-skin aging and wrinkling
-dominant tanning ray
-contributes to development of skin cancer
-redness and sunburn
-damages superficial layers
-key roles in skin cancer development
-poorly penetrates glass
-skin aging and wrinkling