Development and Inheritance Flashcards
In which part of the reproductive tract does fertilization usually occur?
The uterine (Fallopian) tubes
How long after ovulation does fertilization usually occur?
Within 12-24 hours
Define the term capacitation?
Changes the sperm within the female reproductive tract which enables them to carry out the process of fertilization
Define the term cleavage.
The early divisions of the zygote that occur without an increase in cell size
What is a morula?
A solid ball of cells caused by cleavage divisions
What is a blastocyst?
The development of the morula to form a hollow ball of cells
For how long is the developing human considered to be an embryo?
The first 2 months (8 weeks)
Name the 3 primary germ layers.
Ectoderm
Endoderm
Mesoderm
Describe the chorion.
The outermost of the embryonic membranes that surrounds the fetus and becomes the embryonic part of the placenta
Identify the principal function of the placenta.
To provide for the exchange of nutrient and waste products b/w the fetus and the mother
Which structures are found within the umbilical cord?
Umbilical arteries
Umbilical vein
Mucous connective tissue (Wharton’s jelly)
What is the function of human chorionic gonadotropin?
To maintain the structure and function of the corpus luteum
Name the 3 stages of labour?
Dilation
Expulsion
Placental
Define the term genotype.
The specific genetic makeup of an individual
Define the term heterozygous.
Having 2 different forms of the same gene for any particular trait of one individual
Describe what is meant by the term x-linked inheritance.
Refers to a trait carried on the x chromosome
Developmental biology may be best defined as the study of:
Fertilization of a secondary oocyte to the formation of an adult organism
Fertilization is best described as the union of:
A spermatozoa and ovum into a single nucleus
The fertilized ovum - consisting of a segmentation nucleus cytoplasm and zona pellucida - is called a:
Zygote
The embryonic membrane that is closest to the developing embryo is the:
Amnion
Which of the following are changes associated with pregnancy?
Stress incontinence
Increased pigmentation
Constipation
What is capacitation?
The functional changes in sperm after they have been deposited in the female reproductive tract that enable them to fertilize a secondary oocyte.
What is the histological difference between a morula and a blastocyst?
A morula is a ball of solid cells; a blastocyst consists of a rim of cells (trophoblast) surrounding a cavity (blastocyst cavity) and an embryoblast
How does the blastocyst merge with and burrow into the endometrium?
The blastocyst secretes digestive enzymes that eat away the endometrial lining at the site of implantation
At implantation, how is the blastocyst oriented?
The blastocyst is oriented so that the embryoblast is closest to the endometrium
How is the bilaminar embryonic disc connected to the trophoblast?
It is attached to the trophoblast by the connecting stalk
What is the significance of gastrulation?
It converts a bilaminar embryonic disc into a trilaminar embryonic disc
Why is development of the chorionic villi important?
Chorionic villi help to bring the fetal and maternal blood vessels close to eachother
What is the function of the placenta?
Functions in exchange of materials between the fetus and mother, serves Asa protective barrier against many microbes and stores nutrients
How does mid-feral weight compare to end-fetal weight?
During this time, fetal weight doubles
Name 2 functions of oxytocin.
Stimulates contraction of myoepithelial cells in the breasts which squeezes the glandular duct cells and causes milk ejection; stimulates uterine contractions during delivery of a baby
What are chromosomes other than sex chromosomes called?
Autosomes
