Pregnancy & Birth Flashcards
Functions of the Placenta: Endocrine
Secretes a # of hormones necessary for maintaining the pregnancy
Functions of the Placenta: Excretory
Transports nitrogenous wastes such as urea, uric acid, ammonia and creatinine from the foetal blood to the mother’s blood supply for excretion by the mother’s kidneys.
Functions of the Placenta: Immune
Transports antibodies from the mother into the foetal blood supply so that the foetus has immunity to some infectious diseases
Functions of the Placenta: Nutritional
Transports nutrients such as glucose, amino acids, fatty acids, vitamins and minerals from the mother’s blood to the foetal blood; stores some essential nutrients early in pregnancy and releases them later when the demand is greater.
Functions of the Placenta: Respiratory
Transport oxygen from the mother to foetus, and carbon dioxide from the foetus to the mother.
Insemination
When male ejaculates and the sperm are released in the vagina at the entrance of the uterus
The secondary oocyte is surrounded by what two layers?
Corona Radiata
Zona Pellucida
Corona Radiata
Outer layer consists of follicle cells held together by cementing materials that contain acid
Zona Pellucida
Inner layer is a glycoprotein matrix surrounding the plasma membrane of the oocyte.
What does the enzyme on the outer surface of the acrosome (sperm head) do?
Capable of breaking down the acid in the cementing material that holds the cells of the corona radiate together.
Causes digestive enzymes from the acrosome to be released when encountering the zona pellucida.
Outline fertilisation of the egg
Once the sperm has entered the oocyte the tail is absorbed and the head begins to move through the cytoplasm in the form of a male pronucleus - the haploid nucleus of the sperm.
The entrance of the sperm stimulates the oocyte to complete the second meiotic division.
The nucleus of the oocyte develops into a female pronucleus, which fuses with the male pronucleus to form a single nucleus that now has the diploid number of chromosomes.
Fertilisation is complete and the fertilised oocyte is a zygote.
Pregnancy
Period from conception to birth when a woman carries a developing foetus in her uterus.
Duration: 265 days
Zygote
Diploid cell resulting from the fusion of a sperm and an egg
Blastocyst
Hall ball of cells that surround a cavity filled with fluid
- The zygote travels down the uterine tube and begins to divide by mitosis.
By about 6 days after fertilisation, the zygote has developed into a blastocyst and reached the uterus.
- It has become a ball of rapidly dividing cells
When does HCG peak & what is its source?
Peak: 2nd Month
Source: Chorion
When does Progesterone peak & what is its source?
Peak: 9th Month
Source: Corpus luteum / placenta
When does oestrogen peak & what is its source?
Peak: 9th month
Source: Ovary / Placenta
When does prolactin peak & what is its source?
Peak: After Birth
Source: Pituitary gland
Embryonic period
First 2 months of pregnancy
Foetus
The developing individual
(Called that after the 2nd month)