TEST Flashcards
What are genes ?
Segments of DNA (units of heredity) that provide instructions for synthesis of protein
What is a genome?
Genetic makeup of an organism with maternal and paternal genes
How many chromosomes are in non sex cells
46
How many pairs of autosomes are there?
22 pairs
How many pairs of sex hormones are there
1 pair
What are alleles?
They are copies of genes that differ from each other.
What term is used to describe alleles of a gene pair that are different?
Heterozygous
What term is used to describe alleles that are the same for a single trait
Homozygous dominant
What term is used to describe alleles that are suppressed by the dominant allele?
Homozygous recessive
Why are x linked diseases expressed much more commonly in males ?
Because males have only 1 x instead of 2 like females. The male would only need 1 recessive allele to express the disease whereas female would need 2 recessive alleles
What is the embryonic period?
First 8 weeks after fertilization
What is the fetal period
Week 9 to birth
In order for successful fertilization the sperm must reach the ovulated secondary oocyte.
When is the oocyte viable?
12-24 hours
When is the sperm viable?
24-48 hours
What happens when the sperm penetrates the secondary oocyte, what happens to the oocyte?
The oocyte completes meiosis 2 to form the ovum (a mature female reproductive cell)
What happens to the zygote as it moves toward the uterus?
Cell division process referred to as cleavage. Rapid mitotic division
After 72 hours there is a cluster of cells that contains 16 or more cells. What is the name of this solid ball of embryonic cells?
Morula
When do blastocysts form?
Around 4-5 days and consists of 100 cells
What is the composition of a blastocyst?
They consist of trophoblast and embryoblast called the inner cell mass
At what stage of embryonic development does implantation in the uterus occur?
Blastocyst
Know the order of cleavage
Fertilization, zygote, morula, blastocyst, implantation, development of chorionic villi
When does implantation occur?
6-7 days after ovulation
The trophoblast cells secrete chorionic gonadotropin. What is HCG’S function?
Stimulates corpus luteum to continue secretion of progesterone and estrogen
In later stages of pregnancy what produces estrogen and progesterone?
Placenta
What do pregnancy kits test for ?
HCG in urine
What develops into the embryonic organ systems?
Inner cell mass
What is gastrulation?
Occurs 3 weeks, embryonic disc transforms into 3 layered embryo with 3 primary germ layers
What develops from ectoderm?
Becomes the nervous system and skin epidermis
What develops from the endoderm?
Becomes epithelial lining of digestive , respiratory, urogenital systems and associated glands
What develops from mesoderms?
Muscular system
What type of blood is transported in the umbilical arteries
Deoxygenated blood from the fetus to the placenta
What type of blood is transported in the umbilical veins?
Carries oxygenated blood from the placenta to the fetus
What is the ductus venosus?
A shunt that bypasses the liver by draining the umbilical vein into the ductus venosus which empties into IVC
What is the foramen ovale
An opening in interatrial septum bypasses pulmonary circulation
What is ductus arteriosus
A shunt that bypasses pulmonary circulation by draining the pulmonary trunk into the ductus arteriosus into the aorta
When does the reproductive system become active?
It does not become active until puberty
What are gametes produced by the female and male organs?
Sperm produced by testes and ova produced by ovaries
How many chromosomes are in the gametes?
23- bc DNA is reduced during meiosis
What does haploid mean?
23 chromosomes which are present in sex cells
What nomenclature (name) is used to describe haploid?
n= 23 chromosomes
What does diploid mean?
Containing two complete sets of chromosomes 46 total chromosomes that are present in non sex cells
What namenclature is used to describe diploid?
2n,= 46 chromosomes
What is formed from the combination of genetic material formed through fertilization
Zygote
What hormone released from the hypothalamus controls the release of FSH and LH from the anterior pituitary gland?
GnRH controls the release of FSH and LH from the anterior pituitary
What function do these gonadotropins hormones have on the male and female gonads?
In the female LH causes ovulation and FSH stimulates the follicle to further develop in the ovaries. In males LH stimulates testosterone production and FSH stimulates spermatogenesis
What is the pathway for sperm to travel after leaving the testes
Epididymis, vas deferens, ejaculatory duct and urethra
Since the epididymis is the the first part of the duct system after the testes what is its function?
Primary region of sperm storage and maturation
What are the accessory gland of males reproductive system?
Seminal gland, prostate, bulbourethral gland
How are the testes different from the ovary ?
The testes require a lower temperature which is necessary for sperm production
Sperms and ovum carry?
Haploid numbers of chromosomes
