Week 11 - Pregnancy, Menopause, Ageing Flashcards
Fertilization steps
- Sperm enters corona radiata
- Sperm cell contacting zona pellucida (depolorization so other sperm cells cannot enter)
- Sperm enters oocyte
- Sperm and Oocyte nucleus undergo transformation to make Male and Female pronucleus (23 chromosones each)
- Pronucleus combine and form a Zygote (46 chromosomes)
What does the Zygote become a Blastocyst?
~Day 7 in the uterus
What day does the blastocyst burrow into the uterine wall?
Around day 7
Name all of the arrows on the left of this picture from top to bottom and what do these structures form?
Syncytiotrophoblast, Cytotrophoblast, Lacuna filled with maternal blood. They form a protective layer between the maternal arterioles and the embryonic vessels
Stages of pregnancy and the time
Zygote - once male and female nucleus combine
Blastocyst - first 2 weeks
Embryo - 2-8 weeks
Foetus - week 9 to birth
Pregnancy lasts 40 weeks
Human chorionic gonadotropin (hCG)
Secreted by blastocyst and placenta
Found in urine provides indication of pregnancy
Stimulates growth of the corpus luteum x2 in size
= increased amounts of oestrogen and progesterone
Relaxin
Secreted by the corpus luteum and placenta
Relaxes the ligaments of the body
What does the placenta secrete?
Oestrogen: increase water retention and protein synthesis
Progesterone: smooth muscle relaxation, raises body temp
Why do the physiological changes occur during pregnancy?
To provide a suitable environment for the growth, nutrition and development of the foetus
To protect and prepare the mother for the process of pregnancy and support the newborn
Maternal cardiovascular alterations
Blood volume +45-50%
Heart rate +15-25% at rest
Stroke volume increases 30%
Cardiac Output increases 40-50%
When can blood pressure decrease during pregnancy and why?
1st and 2nd Trimester, returns 3rd trimester
Increased progesterone causes vasodilation, heart is pushed upwards and to the side, which increases the size of the heart 70-80ml
Maternal respiratory alterations
Increases in Tidal volume (30-50%)
Minute volume (20-50%)
Decreases in Expiratory reserve volume and residual volume
Why does inspiration increase, but expiration doesn’t during pregnancy?
More oxygen is needed for the foetus, therefore more oxygen is breather in and used.
Maternal renal alterations
Kidneys enlarge - Rengal blood flow (30-50%)
Glomerular filtration rate (50%)
Increased urination
Why can glucosuria occur during pregnancy?
More urination occuring, meaning more glucose may be secreted into the filtrate and not reabsorbed
Thermoregulation during prengnacy
How does the body dissipate additional heat load?
Increase ventilation, increased skin blood flow.
Pregnant women should stay hydrated and avoid high environmental temperatures
Meternal endocrine changes
Anterior pituitary: Increased plasma concentrations of Prolactin
Placenta produces CRH and ACTH
GH, LH, FSH are supressed
Posterior Pituitary: Increased number of oxytocin receptors
Thyroid function increases
Physical changes during pregnancy
Weight gain to the anterior, ligament laxity - Relaxin, Joint mobility, COG moves forward, increased weight of uterus and breasts
Function of pelvic floor
What can happen when these muscles weaken?
Support the pelvic organs: uterus, bladder, bowel
Urinary incontinence, organ prolapse
Menopause occurs when and why and symptoms?
Between ages 40-60 years
Remaining number of follicles is small, Follicles left are less sensitive to FSH and LH, reduced amounts of oestrogen and progesterone
Uncomfortable sweating (hot flushes), anxiety, fatigue, emotional disturbances
Post-menopausal osteoporosis
1 in 3 women, reduction in bone mineral density due to hormonal factors = reduced oestrogen = increased bone loss, increased risk of fractures
Senescence
The process of deterioration with age
Causes of ageing
Complex and multifactorial
What occurs to our cardiovascular system when we age? (4)
Reduction in arterial elasticity - blood pressure can rise quickly due to less room in arteries, out of breath quickly as increased pulmonary capillary pressure
Cardiac tissue - accumulation of lipids and collagen stiffens the heart and makes it less compliant
Heart valves become less flexible
SA node cells decrease altering electrical activity
What happens to HR, SV, CO and VO2?
Declines
Ageing and the respiratory system? (5)
Vital capacity decreased, residual volume increases as we don’t have the power in our lungs to expire, decreased gas exchange across respiratory membrane, gradual rise in tidal volume, mucus builds up
Ageing and urinary system? (6)
Kidneys decrease in size, renal blood flow decreases, glomeruli are destroyed, ability to secrete and absorb declines, loss of responsiveness to ADH and aldosterone, decrease in renin secretion
Ageing and the digestive system? (5)
Thinning of mucosa and submucosa, decrease in blood supply, decrease in smooth muscle cells, less secretions from major secretory organs, muscles of mastication are weakened.
Ageing and the endocrine system (5)
Gradual decrease in secretory activity in some glands, GH levels decrease, Thyroid hormones decrease slightly, Increase in parathyroid hormone but reduced levels of Ca2+ makes bone matrix waste away, Thymosin decreases with age leading to easier infection
Ageing and thermoregulation (3)
Sweat gland secretions decrease, reduced peripheral blood flow = reduced ability to regulate temperature, increased risk of heat exhaustion and illness
