Physiology of Pregnancy Flashcards
What are the components of the female reproductive system
2 ovaries 2 fallopian (uterine) tubes Uterus
What are the functions of an ovary
To produce hormones, to develop the ova
What are the functions of a fallopian tube
Connects ovaries to the uterus, site of fertilisation
What are the functions of the uterus
Cavity, site of implantation of fertilised ovum, where the foetus develops
What are the two components of the uterus
- A cavity lined with epithelial cells (endometrium) 2. An underlying muscle layer (myometrium)
What are the functions of the endometrium
It changes each month to receive a fertilised egg, if fertilisation occurs it develops into a placenta
What is the function of the myometrium
It is required for muscular contractions to give birth
What are the two types of epithelial cells in the fallopian tubes
Ciliated and secretory cells
What is the function of ciliated epithelial cells in the fallopian tubes
They have hairs that waft the ova along the tube towards the uterus
What is the function of secretory epithelial cells in the fallopian tubes
They produce mucus which lubricates the fallopian tubes and keeps them hydrated
What is the function of the muscle layer of the fallopian tubes
To contract in peristaltic movement to propel the ova and sperm and then fertilised egg
What is the developmental process of sperm
Formed in testes, mature as it passes through a series of ducts in the scrotum, final maturation occurs in the female reproductive tract
What is the developmental process of the ovum
Produced in the ovary, oogenesis: occurs in multiple phases, start in utero but only completes if fertilisation occurs
What two cycles make up the female reproductive cycle
Uterine cycle and Ovarian cycle
What is a hormone
A chemical released from an endocrine gland into the blood that causes a reaction often by another organ
What is the purpose of the female reproductive cycle
To release a mature ovum and to prepare the uterus for implantation of the fertilised ovum
Which stages make up the uterine cycle
- Menstruation 2. Proliferative phase 3. Secretory phase
Which stages make up the ovarian cycle
- Follicular phase 2. Ovulation 3. Luteal phase
What is the follicular phase
Development and expansion of the follicular cells
What is ovulation
The release of an ovum
What is the luteal phase
Secretion of progesterone
Summarise the ovarian cycle
- Release of follicle stimulating hormone (FSH) 2. Stimulates follicle growth 3. At ovulation, follicle breaks open to release ovum 4. Ruptures follicle develops into a corpus luteum
What is oogenesis
Process of formation of female gametes (ova)
What is oogonia
Eggs form during early foetal development and undergo mitosis
What are primary oocytes
Division of early eggs gives millions of eggs, most die without further development, the remainder develop into primordial oocytes (one is released every month)
Which hormones are involved in the follicular phase and what do they do
LH and FSH stimulate the growth of follicules
What does LH stand for
Luteinising hormone
What does FSH stand for
Follicle stimulating hormone
Which hormones are involved in the ovulation and what do they do
A surge in LH stimulates the release of the ovum. Oestrogen levels increase resulting in ovulation
Which hormone is secreted by the follicles
Oestrogen
Which hormones are involved in the luteal phase and what do they do
LH transforms an empty follicle to form a corpus luteum. Oestrogen and progesterone are secreted
Which hormones are secreted by the corpus luteum
Oestrogen and progesterone
Which phase of the uterine cycle does the follicular phase relate to
The proliferative phase
Which phase of the uterine cycle does the luteal phase relate to
The secretory phase
What happens in the proliferative phase
Oestrogen stimulates the thickening of the endometrium (part of the uterus preparing for implantation)
What happens in the secretory phase
The corpus luteum maintains the development of endometrium (as it secretes hormones) and the endometrial glands secrete a nutrient fluid (as implantation occurs to feed to embryo)
What happens in the menstrual phase
Loss of the corpus luteum and ovarian hormones occurs (as levels of LH fall), disintegration of the endometrium occurs and menstrual (blood) flow occurs.
How long after ovulation does fertilisation occur
12-24 hours after
How long is an oocyte viable for
24 hours
How many sperm enter the vagina
300 million
How many sperm reach the cervix
60 million
How many sperm pass through the cervix
6 million
How many sperm reach the fallopian tubes
100
What is capacitation
The removal of glycoprotein from the plasma membrane around the surface of the head of the sperm
How long do sperm have to be in the female reproductive system until they are fertile
7 hours in order to be able to undergo capacitation
Describe the 5 stages of fertilisation
- Interaction of sperm with the outer region of the egg 2. Release of enzymes from the sperm head 3. Enzymes digest a path through the outer oocyte 4. Enzymes interact with the outer membrane of the oocyte 5. The sperm moves into the egg
What happens on day 1 of the first week
Ovulation and formation of a secondary oocyte
What happens on day 2 of the first week
A fertilized ovum is formed via fertilisation and meiosis II
What happens on day 3 of the first week
Fusion of pronuclei produces a zygote
What happens on 4 of the first week
A zygote is formed
What happens on day 5 of the first week
Cleavage forms a morula
What happens on day 6 of the first week
Differentiation forms a blastocyst
What happens on day 7 of the first week
Hatching occurs
When does implantation occur
On day 8 after differentiation
How long is pregnancy from ovulation
266 days (38 weeks)
How long is pregnancy from last menstrual period
280 days (40 weeks)
What does the first trimester consist of
Conception, implantation, development of the placenta and organogenesis
When are all organs in place by
Week 8, they are not nature but they are present
When does the heart start to beat
Week 4
When is it known as an embryo
From implantation to week 8
When is it known as a foetus
When all organs are formed, so from week 8
What does the placenta develop from
The mother and embryo
What does the mother contribute to the placenta
The endometrium if the uterus
What does the embryo contribute to the placenta
Trophoblast cells which form the villi Foetal blood supply is located within the villi
What are the 6 functions of the placenta
- Synthesis of hormones 2. Respiratory gas exchange 3. Nutrient transfer 4. Waste product removal 5. Heat transfer- ensures the foetus remains at a constant temperature 6. Protection of the foetus Some Girls Nuke Women Hair Perfume
What is transferred from mother to foetus by the placenta
Oxygen, nutrients, hormones and antibodies
What is transferred from foetus to mother by the placenta
CO2, other metabolic waste, hormones and water
What happens during the second trimester of pregnancy
The foetus grows to 30cm and is very active. The uterus has to cope with the needs of the growing foetus
What happens during the third trimester of pregnancy
- Growth of the foetus as it reaches 3-4kg in weight and 50cm in length 2. Foetal activity decreases due to a lack of space 3. Labour
What changes happen to the cardiovascular system during preganacy
- Increased blood volume and blood cells 2. Increased cardiac output 3. Increased blood flow to organs
What does increased blood volume and blood cells do
To make sure there is sufficient blood going to the placenta
What does increased cardiac output do
Push more blood around the body
Where is blood flow increased to and why
- To the kidneys for waste disposal 2. To the uterus as it takes substances to and from the placenta 3. To the skin for heat loss 4. To the breasts for mammary development to prepare for lactation
What changes happen to the respiratory system during pregnancy
- An increase in oxygen taken into the lungs 2. An increase in oxygen passing across the alveoli 3. Rapid removal of CO2 The above combined ensures sufficient oxygen for the foetus
What changes happen to the gastrointestinal system during pregnancy
- An increase in food intake 2. Slow transit of food through the GI tract 3. Increased absorption from the GI tract Results in ensuring there is a good nutrient supply
What changes happen to metabolic function during pregnancy
- Reducing mother’s dependence on glucose 2. Increasing fat breakdown 3. Inhibiting amino acid breakdown Results in increased waste removal and retention of salt and water
What is the purpose of maternal adaptations
To ensure that the foetus gets oxygen and nutrients that waste is removed
Why is development of the ovum correlated with preparation of the endometrium
So that the endometrium is ready to receive the fertilised egg
What do all stages of pregnancy require
The correct balance of hormones
What is the purpose of placenta development
To provide a good exchange system between mother and foetus
Describe the adaptations to pregnancy
Adaptation
Describe the stages of the first week of pregnancy
Summarise the ovarian cycle
Describe the structure of an ovary
Describe a placenta
