David Taylor dcmtlivacuk httppcwwwlivacukdcmthpoapptx Resources I have used Naish Kumar and Clarke Davidsons And there are dozens of other webbased resources wwwmedicinenetcompregnancyarticlehtm ID: 553655
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Slide1
Physiological changes during pregnancy
David Taylor
dcmt@liv.ac.uk
http://pcwww.liv.ac.uk/~dcmt/hpoa.pptxSlide2
Resources
I have used
Naish
Kumar and Clarke
Davidson’s
And there are dozens of other web-based resources
www.medicinenet.com/pregnancy/article.htm#
has lots of pictures....Slide3
scenario
After 3 months, when her menstrual period is 6 days late, Ms Garnett buys a testing kit. They are pleased that it confirms pregnancy.
“
Don’t
fuss, Mum.
I’m
pregnant – not ill… feeling sick, lots of hormones, lots to decide, and
I’ve
got my first appointment with the doctor soon!” Slide4
Learning outcomes
Outline the hormonal control of menstruation and the menstrual cycle (with reference to the structure and function of the pituitary and hypothalamus)
Outline
the key features of normal pregnancy including physiological
, immunological, biochemical, and anatomical
changes to the mother, and the main hormonal controls (the endocrine system) on maintaining pregnancy
and developing breast function and producing breast-milk,
including the structure and function of the breast
Slide5
Hypothalamic-pituitary axis
Understanding this is fundamental to understanding endocrinology.
We will be focussing on its effect on the female reproductive organs,
but remember that the hypothalamus is also part of the limbic system.Slide6
Anatomical relations
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2.1 Japan
LicenceSlide7
MRI scan of brain removed for copyright reasons
Kumar and Clarke,2009
7
th
edition
Fig 18.6Slide8
In more detail
This image, originally from the 1918 version of Gray’s Anatomy, is in the
public domain
because its copyright has expiredSlide9
Posterior pituitary
The axons of hypothalamic neurones pass down the
infundibulum
. Hormones formed in the
hypothalmus
are transported by axonal transport and are released from the nerve terminals in the posterior pituitary into the circulation (inferior hypothalamic artery).
Examples of these hormones are
Oxytocin
(smooth muscle contraction)
ADH (blood pressure)Slide10
ADH and Oxytocin
Inferior
Hypothalamic
artery
To target tissue
StimulusSlide11
The others
Stimulus
Superior
Hypothalamic
artery
To target tissueSlide12
The hypophyseal
portal system
1. Releasing/inhibitory hormones
3. Hormones to target tissues
2Slide13
Anterior pituitary hormones
Dopamine
VIP
TRH
Somatostatin
GRH
Dopamine
GnRH
CRH
PRL
TSH
GH
FSH/LH
ACTH
Mammary glands
Thyroid
Liver and others
Gonads
AdrenalsSlide14
Focus on menstrual cycle
hypothalamus
pituitary
follicle
GnRH
LH
FSH
oestradiol
inhibin
Early follicular
hypothalamus
pituitary
Antral
follicle
GnRH
LH
FSH
oestradiol
Pre-
ovulatorySlide15
Focus on menstrual cycle
hypothalamus
pituitary
Corpus
luteum
GnRH
LH
FSH
progesterone
oestradiol
Early
luteal
hypothalamus
pituitary
Antral
follicle
GnRH
LH
FSH
oestradiol
Pre-
ovulatorySlide16
The menstrual cycle
The growing follicle produces
Oestradiol
Which enhances FSH/LH release
The Corpus
luteum
produces progesterone
Graph of hormonal changes during menstrual cycle removed for copyright reasons.
Naish
et al.,
2009
1
st
edition
Fig
10.2Slide17
oestradiol
Endometrial proliferation
Genital development and lubrication
Breast proliferation
Bone
epiphyseal
closure and mineral content
Brain
Body fat
Skin sebum
progesterone
Endometrial
secretory
change
Increased
myometrial
contractility
Thermogenesis
Breast swellingSlide18
http://i497.photobucket.com/albums/rr332/hbomb1984/untitled.jpgSlide19
Hormone changes during pregnancy
The
syncytiotrophoblast
produces
hCG
Human chorionic
gonadrotrophin
hCG
binds to LH receptors, and maintains the corpus
luteum
which produces progesterone
As the placenta develops it takes over the production of progesterone.Slide20
Cardiovascular changes in pregnancy
Peripheral vascular resistance decreases
progesterone decreases vascular smooth muscle tone
Oestrogen causes
vasodilation
through nitric oxide
Placenta releases
prostacyclin
(vasodilator)
Consequently blood volume, cardiac output and GFR increase
Blood pressure, plasma
creatinine
and urea should decrease in 1
st
trimester.Slide21
Respiratory changes in prgnancy
Progesterone increase body temperature, therefore metabolic rate
So oxygen consumption increases
Progesterone increases sensitivity of central
chemosensors
to CO
2
increasing tidal volume but not respiration rate
Also physical changes in space available means that more of the
inspiratory
reserve volume is used.Slide22
GI changes in pregnancy
Energy intake needs to increase by 1200kJ/day
Smooth muscle tone and motility decreased due to progesterone
Constipation
Increased transit time for food
Acid reflux to the above and physical pressure
Nausea and vomiting in 1
st
trimester are due to rising levels of ovarian
steriodsSlide23
Brain adaptations
Not really understood (progesterone metabolites on GABA pathways?), but the
neuroendocrine
response to stress is reduced in pregnancy.
Pituitary increases in size during pregnancy
Due to increased
prolactin
and ACTH secretion from AP
And increased
oxytocin
production from PP (where it is stored until progesterone levels drop)Slide24
Other endocrine changes
T3 and T4 increase due to
hCG
, but remain bound to plasma proteins
Because oestrogen increases
thyroxine
-binding globulin (TBG)
Maternal bound T4 is a “reservoir” of thyroid hormone for the foetus
Foetus uses Calcium, which stimulates maternal PTH output
Increased absorption,
reabsorption
and mobilisation of Ca
2+Slide25
Learning outcomes
Outline the hormonal control of menstruation and the menstrual cycle (with reference to the structure and function of the pituitary and hypothalamus)
Outline
the key features of normal pregnancy including physiological
, immunological, biochemical, and anatomical
changes to the mother, and the main hormonal controls (the endocrine system) on maintaining pregnancy
and developing breast function and producing breast-milk,
including the structure and function of the breast