Human Development Flashcards
Difference between:
a) Exocrine and endocrine glands
b) Exocrine and endocrine secretions
a) Exocrine - secrete via duct, Endocrine - direct into circulation
b) Exocrine - Outwith body, Endocrine - within body
Describe action and give example:
a) Paracrine
b) Autocrine
c) Neurocrine
d) Endocrine
e) Neuroendocrine
a) Acts on cell close by e.g. His from mast cells
b) Acts on same cell e.g. interleukins
c) Electrical signal passed on via synapse e.g. NT
d) Produce 1 prt body, travel in blood e.g. insulin
e) Elec signal passed on via circulation e.g. dopa inhibition of prolactin release
What is the difference between alpha and beta chain in glycoprotein hormones?
Alpha - Species specific
Beta - Hormone specific
What glycoprotein hormone is released from placenta?
Human Chorionic Gonadotropin
Function and example of:
a) Mineralocorticoid
b) Glucocorticoid
c) Sex steroid
a) Affect H20 + electrolyte balance e.g. aldosterone
b) A’’ carb + protein metabolism e.g. cortisol
c) Sexual characteristics e.g. oestr, testos
What types of hormones circulate in :
a) Free form?
b) Bound form?
a) Catecholamines, proteins/peptides
b) Thyroid + steroid hormones
What 2 types of hormones are stored in secretory granules/vesicles?
(How released)
Catecholamines + Peptides
Release via exocytosis, triggered by Ca2+
What are the 5 types of hormone release? + example
Pulsatile - episodic release e.g. LH/FSH hourly release
Circadian - based 24hr cycle e.g cortisol
Diurnal - synchronised to day/night cycle more animals
Infradian - Longer than 24hr cycle e.g. menstrual cycle
Seasonal - More animal e.g. prolactin
What types of hormones are:
a) Hydrophilic?
b) Lipophilic?
How does this affect binding to plasma proteins?
a) Catecholamines + Peptides
b) Thyroid + Steroid hormones
Hydrophilic x bind, lipophilic binds
How many parts does the pit. gland have?
What are they made up of?
Ant lobe (Adenohypophysis) - Pars distalis + tuberalis Neuro-intermediate lobe - Pars intermedia + nervosa Post lobe (neurohypophysis) - Pars nervosa + infundibulum
What is another name for pit. gland?
Hypophysis
Which part of the pit gland is not well developed in man?
Neuro intermediate lobe
What is the growth hormone inhibiting hormone?
Somatostatin
What is the:
a) Releasing hormone
b) Inhibitory factor/hormone
of prolactin?
a) TRH
b) Dopamine
What is the main cell type of ant pit?
What do they produce?
Somatotrophs
Growth hormones
What hormone suppresses menstrual cycle in lactating mother?
Prolactin
Via what receptors does dopamine inhibit prolactin?
How would you treat them in hyperprolactinemia?
D2 receptors
Selective D2 agonists e.g. bromocriptine, cabergoline
What types of somatostatin analogues work better on:
a) Type 2 somatostatin receptor
b) Type 5 somatostatin receptor
Which one is better?
a) Octreotide + Lanreotide
b) Pasireotide
Type 5, pasireotide
What carrier molecule is associated with:
a) Oxytocin?
b) ADH?
a) Neurophysin I
b) Neurophysin II
What happens to colloid space in:
a) Underactive thyroid?
b) Overactive thyroid?
a) Large colloid spaces
b) Little/no colloid spaces also hyperplasia of follicular cells
What happens to fetus if thyroid hormones are not properly delivered?
Cretinism
What is a goitrogen?
Substances disrupt production of thyroid hormones by interfering with iodine uptake in thyroid gland
Increase TSH secretion to form goitre
What is the additional effect of propylthiouracil?
Prevents peripheral conversion of T4 to T3
How much of the bodies iodine is found in the thyroid gland?
60-65%
What defines iodine deficiency?
Less than 50 micrograms a day
Where are adrenal glands located and shape?
On top of kidneys
RHS - pyramidal
LHS - oval shape
What are the layers of the kidney from outside to in?
Zona glomerulosa
Zona fasciculata
Zona reticularis
What does the medulla of the adrenal gland produce?
What percentage?
Adrenaline - 80%
Noradrenaline - 20%
What does the zona glomerulosa produce?
What enzyme does it lack and why?
Mineralocorticoids e.g. aldosterone
17-alpha hydroxylase, x produce cortisol
What does the zona fasciculata produce?
What enzyme does it lack and why?
Glucocorticoid e.g. cortisol
Aldosterone synthase, x produce aldosterone
What does the zona reticularis produce?
What enzyme does it lack and why?
Adrenal androgens eg. androstenedione, DHEA (a little cortisol)
Aldosterone synthase
What are all steroid hormones derived from?
Cholesterol
What is an example of an aldosterone antagonist?
Spironolactone
What is affected in these types of hypothyroidism?
a) Tertiary
b) Secondary
c) Primary
d) Resistance
a) Hypo/TRH
b) Pit. gland/TSH
c) Thyroid/T3+T4
d) Periphery/alpha thyroid receptors
Where is the pituitary gland located in the skull?
What is it called?
Sphenoid bone
Pituitary fossa
What structure is located above pit. gland?
Optic chiasm
What would you test for pituitary hypo function?
Measure pituitary hormone and target hormone
What are the 2 ways pituitary tumours can be categorised?
Sub categories?
Size - microadenoma (<10mm)/macroadenoma (>10mm)
Functioning - endocrine syndromes/non-functioning
What are 3 examples of diseases caused by non-functioning macroadenoma of the pit gland?
Cushing’s disease
Acromegaly
Prolactinoma
How are majority of:
a) Macroadenoma of pit gland
b) Microadenoma of pit gland treated?
What is used in regrowth?
a) Surgically (trans-sphenoidal)
b) Medically/Conservatively
Radiotherapy
What type of pit gland tumour can be treated well medically?
Prolactin secreting tumours
When would radio-iodine therapy be avoided in the treatment of hyperthyroidism?
Thyroid eye disease
What % of thyroid nodules are benign?
90%
What is the main type of thyroid cancer? (+ %)
What is the prognosis?
Papillary thyroid cancer, 85%
5 yr survival >98%
What is a pheochromocytoma?
Tumour of adrenal medulla
Meaning of ‘gravidity’ (relation to pregnancy)
No times uterus has been pregnant, inc current pregnancy
Meaning of ‘parity’ (relation to pregnancy)
No babies she has given birth to at 24 weeks or later, born alive/dead
+ superscript of other pregnancies up to
23 weeks (miscarriage, ectopic, TOP)
What blood pressure values are used for hypertension in pregnant women?
140/90 - hypertension
160/110 - severe hypertension
What is pre-eclampsia (PET) in pregnant women?
When does it usually occur?
Raised BP 140/90 + Protein in urine
After 20 weeks
Why should a pregnant women not be on her back more than a min?
Impaired venous return via IVC - supine hypotension
What observation chart is used in obstetrics?
MEOWS
What pregnancy stage is dating scan used?
What fetal measurement is used to calculate expected date of delivery?
11-13 weeks
Crown-rump length of fetus, calculates gestational age
What is the symphyseal- fundal height?
What body parts are included?
Assess growth of fetus + growth of uterus
Pubic symphysis - Fundus (top if uterus)
Cm
What stage of pregnancy is symphyseal- fundal height measured?
What is expected growth?
Every antenatal visit from 24 weeks
Same amount cm as weeks pregnant +/- 2cm
What is the name of the division of the testicles? (anatomically)
What is contained within them?
Lobules
Seminiferous tubules
What 2 types of cells line the seminiferous tubules of the testicles?
What do they do?
Spermatogonial stem cells - gamete (sperm) production
Sertoli cells - support, nutrit, protec, secretory, excretory
How much sperm is produced during spermatogenesis?
How long does the whole process take?
Approx 120 million p/day // 1500/sec
72 days
What is spermiogenesis?
Conversion of spermatid to mature sperm
Becomes longer + thinner, mito go around neck of sperm
What are the names of the different parts during spermatogenesis? (the different cell types)
Spermatogonia, Primary + 2ndary spermatocytes, Primary + 2ndary spermatids, spermatozoa (mature)
What is the structure of a mature sperm cell?
Head - nucleus, acrosome
Neck - mito
Tail
What compartment of the seminiferous tubules are mature sperm cells produced?
Luminal compartment
What comprises the interstitial compartment of the seminiferous tubules of the testicles?
Basal spermatogonial stem cells
Interstitial cells of Leydig
Why are there 2 compartments in the seminiferous tubules of the testicles?
Separates newly formed sperm cells
Protect from immune system from being seen foreign
What cells in seminiferous tubules of the testicles remove degenerate sperm cells?
Sertoli cells
What hormones do the Sertoli cells of the seminiferous tubules of the testicles produce?
Inhibin, ABP (androgen binding protein)
AMH (anti Müllerian hormone), growth factors
What hormone do the interstitial cells of Leydig secrete?
What is it’s actions?
Testosterone, C19
Anabolic, primary + 2ndary sexual character, libido, stimulates sertoli cells + spermatogenesis
What hormones inhibit:
a) FSH
b) LH
production in males?
a) Inhibin
b) Testosterone
What are the 4 stages of sperm transport (to get fertilised)?
Short Descrip
Ejaculation
Cervix - mucous barriers + crypts = sperm resevoir
Uterus + tubes - mild contraction to propel towards egg
Ampullary portion of tube - fertilisation
What is sperm capacitation?
What happens?
Sperm becomes ‘hyperactivated’, more speed
4 hours after ejaculation
Cholesterol loss + Ca2+ influx
What happens to sperm as it reaches the oocyte?
Interaction of ZP3 protein on oocyte membrane
Acrosome reaction releases enzymes
Facilitates penetration
What enzymes are contained within acrosome of sperm cell?
Hyaluronidase
Acrosin enzymes
How is the oocyte activated after penetration from sperm cells?
Release of cortical granules to block polyspermic penetration
Resumption of meiosis
What factors can affect sperm production?
Excess testost intake
Environ
Air pollution/Smoking
Food chain pollution
What is the mechanism that can affect sperm production?
Free O2 radicals e.g. O2, H2O2, OH
What is the NICE definition of infertility?
Woman of reproductive age who x conceived after 1 year of unprotected sexual intercourse
What 3 factors can affect chances of pregnancy?
Previous pregnancy
Duration less than 3 years
Age less than 30 years
How would you test ovulation?
Midluteal progesterone, 7 days before next expected period
How would you test semen?
Test: concentration, mobility, morphology
How would you test ovarian reserve?
Early follicular FSH
Antral follicle count (AFC) - measuring size of follicles
Anti-Mullerian Hormone (AMH)
Where is AMH produced in females?
When can it be measured (to test for ovarian reserve)?
Produced by granulosa cells from pre-antral + antral follicles
Measured anytime in cycle
What is anovulation?
What are the 3 types?
Ovaries x release oocyte during menstrual cycle
Group I: hypothalamic amenorrhoea/ hypogonadotropic hypogonadism, 20%
Group II: hypothalamic-pituitary-ovarian dysfunction
(predominately polycystic ovary syndrome)
Group III: ovarian insufficiency.
What 3 common drugs are used to treat anovulation?
Clomiphene citrate - selective oest receptor
Letrozole - aromatase inhibitor
Gonadotrophins
What is azoospermia?
What are the 2 types?
Semen present but no sperm
Obstructive - normal spermatogenesis, normal sized testes + FSH levels
Non-obstructive - impaired spermatogenesis, small testes + raised FSH
What are the common causes for the 2 types azoospermia?
Obstructive - post infection/vasectomy, congenital absence of vas deferens
Non-obstructive - testicular failure,
What is the common treatment for azoospermia?
Sperm retrieval
Percutaneous epididymal sperm aspiration (PESA)
Testicular sperm extraction (TESE)
What is ICSI?
Intracytoplasmic Sperm injection
Part of IVF to get sperm ready
When does a fetus acquire legal rights?
At birth
When was Abortion Act established?
What criteria have to be met?
1967
2 registered practitioners of opinion, 1/4 grounds exists
Carried out by Registered medical practitioner
Procedure performed in an approved place
Notified to Chief Medical Officer of DoH
When was the Abortion act amended?
1990
What abortion can be carried out at home?
How many weeks of pregnancy
First 10 weeks
What is ART?
Assisted Reproductive Technologies
e.g. IVF, artificial insemination, surrogacy
What is preimplantation genetic diagnosis(PGD)?
Cell from an embryo at 8-cell stage of development, Around 3-days old, + testing it
In the 1st 5 days of human development, what is formed?
Blastocyst
What is contained in a blastocyst?
Trophoblast layer - embryonic contribution to placenta
Inner cell mass - totipotent cell types
What does the inner cell mass of the blastocyst divide into?
Epiblast - ecto/meso/endoderm, amniotic membrane
Hypoblast - Heuser’s membrane
When is the heart and brain visible in a developing fetus?
Week 2
When does the heart start to beat?
Week 3
What is the embryonic development period in human development? (What weeks)
Weeks 3 -8
Most organs develop
What process leads to the germ layers in human development?
Gastrulation
What organs do the 3 germ layers give rise to?
Ectoderm - epidermis, nervous system
Mesoderm - skeleton, muscle, dermis, kidney, blood
Endoderm - gut, liver, pancreas, lungs
Where do the brain and spinal cord develop on the ectoderm?
On the midline
What is the name of:
a) Anterior
b) Posterior
when looking at fetus?
a) Rostral
b) Caudal
What are 3 examples of endodermal defects?
Lung aplasia - no lungs
Oesophageal atresia/fistula
Omphalocele
What are the 3 divisions of the mesoderm?
Paraxial mesoderm
Intermediate mesoderm
Lateral plate mesoderm - somatic + splanchnic mesoderm
What structures arise from lateral plate mesoderm?
Dermis of skin, Limb Skeleton, Heart, Blood vessels, Blood, connective tissue
Mucosal + muscle layers of gut
What structures arise from intermediate mesoderm?
Kidneys, M + F reproductive systems
What structures arise from paraxial mesoderm?
Vertebrae + ribs, muscles of body, dermis of skin (back)
What are the cell types in the neural crest?
What can they arise from?
Multipotent Cranial from brain Vagal from cordal hindbrain Trunk Sacral
What is Hirschsprung’s disease?
Failure of vagal/sacral neural crest to migrate ==> post regions of gut
Bowels contents build up proximal to affected region, causing it to expand
What is Liebenburg syndrome?
Abnormal expression of arms so have leg like characteristics
Mutation in Pitx1 gene that usu goes to leg
What viruses represent acronym TORCH?
Toxoplasma parasite Other viruses e.g. parvovirus Rubella Cytomegalovirus Herpes
What is a teratogen?
Agent that causes an abnormality following fetal exposure during pregnancy
How many births are affected by fetal alcohol syndrome?
1 in 500 live births
What is oligohydramnios?
Too little amniotic fluid
What are amniotic bands?
Bands of amnion (inner lining of amniotic sac) peel away from sac and attach/wrap around prts of fetus
What is the main concern for premature babies?
Lungs x fully developed, neonatal respiratory distress syndrome
Cut off survival 22 weeks
What week of pregnancy does the neural tube close in?
Week 3
Why can’t a baby survive before 22 weeks?
Lung x developed alveoli
What is reduced penetrance?
Proportion of mutation carriers who manifest clinical signs of condition
If some peeps mit mutation X develop features of disorder, condition has reduced/incomplete penetrance
Oft seen in hereditary cancer syndromes
What is variable expressivity?
Degree condition is expressed (ie severity) in person
Variable between families /within families
Oft seen in chromo deletion / duplication syndromes
What are the 2 parts of the ovaries?
What do they contain?
Medulla - blood vessels
Cortex - follicles at diff stages of development
What is ovarian reserve?
What’s the normal amount in a healthy woman?
Number of follicles visible in ovary at any given time
10-20 follicles
What is atresia in the ovaries?
Breakdown of ovarian follicles which contains an oocyte
What are the 3 phases of the Ovarian cycle?
Phase 1 - Follicular phase, Days 1-10
Phase 2 - Ovulatory phase, Days 11-14
Phase 3 - Luteal Phase
What happens during Phase 1 of Ovarian cycle?
Hormones signal causes 10-20 follicles to grow
Growing follicles produce estrogen
What happens during Phase 2 of Ovarian cycle?
Dominant Follicle causes signif rise of oestradiol
follow by LH surge
Follicle wall thins + ruptures
Oocyte enters abdominal cavity near fimbriae of fallopian tube
How is the oocyte propelled along the fallopian tubes?
By cilia and fallopian tube contractions
What happens during Phase 3 of Ovarian cycle?
After ovulation, hemorrhage into remains of follicle usu occurs
Structure corpus hemorrhagicum forms
Develops into corpus luteum (yellow body)
What reproductive hormones are present in women?
What do they do?
Gonadotropins - FSH (maturation), LH (release) act on ovaries
Oestrogen - maturation of reproductive organs, menstruation, + pregnancy
Progesterone - helps maintain uterine lining
What are the suspensory ligaments of the uterus?
Broad ligament
Uterosacral ligaments
Round ligaments
Lateral (cardinal ligaments)
What are the functions of the uterus?
Transports to tubes for fertilization Provides suitable environment for - implantation of the embryo - nourishment of embryo + fetus during pregnancy Mechanical protection of fetus Expels mature fetus at end of pregnancy
What are the 3 segments of the fallopian tube?
Infundibulum - lots fingerlike projections - fimbriae
- inner surface covered with cilia
Ampulla
Isthmus
What are the 5 layers of the fallopian tube (outside to in)
Tunica serosa Tunica muscularis Tunica submucosa Tunica mucosa Lumen
What part of the fallopian tube has a bigger lumen?
Ampulla
What is the embryology of the ovary?
Primordial germ cells (PGC) emerge in wall of yolk sac
as cluster of about 20 cells
Synchronised PGC migration to genital ridge
Sex differentiation from a bipotential gonad
At genital ridge – mitosis up to 8 weeks
Mitosis + meiosis from 8 to 28 weeks
20 weeks gestation ~ 7 million germ cells
From 20 weeks, atresia dominates
At birth, there are about 1-2 million germ cells
During 1st yr of life, ovaries migrate ==> true pelvis
What happens during oogenesis and folliculogenesis?
At birth all primordial oocytes (inside primordial
follicles) arrested at Prophase 1 of Meiosis I
Most primordial follicles undergo atresia from birth to menopause
Meiosis I makes 2ndary oocyte, 1st polar body (dies)
2ndary oocyte arrests at metaphase II of Meiosis II
Ovulation occurs
Meiosis II only completes when egg fertilized, 2nd polar body extruded to prevent triploidy
All happens alongside follicular development and
ovulation
How long can folliculogenesis take?
300 days+
What is the climacteric (in relation to menopause)?
Period of time around last menstrual period
AKA perimenopause
What is the difference between continuous and sequential HRT (in relation to menopause)?
Continual - oest + progest taken every day, same levels for rest of life
Sequential - oest taken every day, progest every 2 weeks
In the follicular stage of the ovarian cycle, what are the different stages (diff cell types)?
Primordial follicle, Primary follicle, 2ndary follicle, Tertiary follicle
Levels of which hormone spike before ovulation?
How many hours before?
LH
34-36 hours before
Where is the oocyte released into during ovulation?
Abdominal cavity near fimbriae of fallopian tube
What hormones does the corpus luteum produce?
Oestrogen and Progesterone
What happens to corpus luteum when:
a) Egg is fertilised?
b) Egg x fertilised?
a) Continues produce hormone until placenta formed
b) After 2 weeks, degenerates into corpus albicans, x produce hormones
What hormone is present that prevents corpus luteum from degenerating when an egg is fertilised?
Human chorionic gonadotropin (hCG)
What are the 3 stages of the uterine cycle?
Menstrual phase
Proliferative phase
Secretory phase
In what phase of the uterine cycle does growth of the follicles occur?
Menstrual phase
What phases of the uterine cycle does the growth of the endometrium occur?
When does it have good vasculature?
Proliferative + Secretory phase
Secretory phase
What are the 2 layers of the endometrium?
What layer sloughs off during menstruation?
Stratum basalis + functionalis
Stratum functionalis
When during the uterine cycle are progesterone levels at their highest?
When the walls of the endometrium are the thickest
What zone of adrenal gland is regulated by renin-angiotensin system?
Zona glomerulosa
What are 3 common causes of chromosomal aneuplodies?
Due to malsegregation either:
Gonads during meiosis ==> abnormal gametes
Mitosis in germline ==> mosaicism in gonad
Mitosis in early embryo ==> mosaicism in embryo
What is Robertsonian translocations?
Fusion of 2 acrocentric chromos - 13,14,15,21,22 (long arms fuse)
Prevalence 1 in 1000
What are reciprocal translocations?
Exchange of material between 2 non-homologous chromos
Prevalence 1 in 500
What are some invasive methodologies for prenatal testing?
Chorionic villus sampling (CVS)
Amniotic fluid sampling
Fetal blood sampling
What are some non invasive methodologies for prenatal testing?
Peripheral maternal blood sampling e.g. biochem screening
Analysis of free fetal DNA in maternal circulation (NIPT & NIPD)
What is the difference between:
a) Genetic testing
b) Genetic prenatal screening
in prenatal genetic tests?
a) sample from pregnancy for presence of specific disorders, invasive techniques, produces diagnosis
b) Risk figure of fetus having certain abnormalities, x diagnosis, +ve results follow up by specific diagnostic test
Antenatal testing for what conditions are offered routinely to pregnant women?
Infectious diseases - Hep B, HIV, Syphilis
Thalassemia
When is the fetal anomaly scanned carried out? (What stage of pregnancy?)
18-21 weeks
From what weeks of pregnancy is screening for Down syndrome. Edward’s + Patau’s syndrome offered?
What screenings can patients choose from?
10-14 weeks
All 3 conditions, Down syndrome only, Edwards’ + Patau only, No screening
What is the definition of:
a) Preconceptual?
b) Periconceptual?
a) 1-3 months prior to conception
b) Immediately prior to conception + early gestational phase
What weeks are the different trimesters in pregnancy?
1st - 0-13 weeks
2nd - 14-26 weeks
3rd - 27-40 weeks
What is:
a) Anencephaly?
b) Spina bifida?
a) Incomplete closure of upper end neural tube (x brain)
b) Incomplete closure of spinal cord (split spine)
What are the folate recommendations in UK for women planning pregnancy?
400 micrograms per day until 12 weeks postconceptually
What are some maternal adaptations to meet increased Ca requirements?
↑ intestinal absorption of dietary Ca
↑ reabsorption Ca by kidneys ==> enhanced retention
↑ bone turnover to release Ca
What are some maternal adaptations to meet increased Fe requirements?
Amenorrhoea, ↑ absorption of dietary non-heme Fe, mobilisation of maternal stores
Fetus acts ‘parasite’ drawing on maternal stores (risk Fe deficiency anaemia in mothers mit low Fe stores)
What is the definition of:
a) Exclusive breastfeeding
b) Weaning
c) Complementary feeding
a) X food/drink (inc H2O) ‘cept breast milk (exception vitamin/mineral supplements, medicines)
b) Expanding diet to inc food + drinks other than breast milk/ infant formula
c) Giving foods + liquids in addition to breast milk/infant formula) when these X longer sufficient meet nutritional needs of infants
For how long is exclusive breastfeeding recommended for?
What is the only recommended alternative to breastfeeding for infants <12 months?
First 6 months/26 weeks of infant’s life
Infant formula
What are the 3 signs of readiness for solid food (in an infant)?
- Can stay in a sitting position + hold their head steady
- Can coordinate eyes, hands + mouth so can look at
food, pick it up + put it in their mouth by themselves - Can swallow food, babies who X ready will push food back out
Why is there no placental blood flow during the first trimester?
Volume of endovascular trophoblast blocks mouths of arteries so maternal blood x flow into placenta
What type of nutrition does the embryo receive in the first trimester?
Histiotrophic nutrition - Nutritional material in spaces between maternal + fetal tissues, derived from maternal endometrium + uterine glands
What type of nutrition does the embryo receive when maternal blood flow to placenta is established?
Hemotrophic nutrition
What blood vessel carries oxygenated blood to the embryo?
Umbilical vein
How many umbilical blood vessels are there?
2 umbilical arteries
1 umbilical vein
What is the intervillous space in the placenta?
Pools of maternal blood
Does the maternal blood and placental blood mix?
No, substances diffuse via placental membrane
What are the 3 amino acid transporters across the placenta?
System A - Na dependant, transports small non-essential AA
System L - Na independant, non essential AA exchanged for essential AA
Taurine transporter - cotransport with NA + Chloride
What are the isoforms of the ‘System A’ AA transport in placenta?
Which one is the main contributor to system A activity?
SNAT1, SNAT2, SNAT4
SNAT1
What is:
a) System A
b) System L
regulated by? (AA transport in placenta)
a) Cytokines + hormones
b) mTOR nutrient sensing pathway
What transporter is mostly used for glc transport in second half of pregnancy?
GLUT1
How is FA transport carried out in placenta?
MATERNAL: Lipoprotein lipase releases non-esterified FA (NEFAS) from triglycs in lipoproteins (LP)
FETAL: NEFAS transported across trophoblast cells by FA transport proteins (FATP)
When are the intestinal villi formed in the fetal alimentary tract?
Intestinal villi formed by 16 weeks
Well developed by 19 weeks gestation
When does the fetus swallow amniotic fluid?
From 12 weeks gestation
What hormones does the fetal gut produce?
Gastrin, Motilin, Somatostatin
Present in gut at 13 weeks, maturity by 24 weeks
When are digestive enzymes present in in fetus?
Present by 9-10 weeks
Maturity at term
When does the fetus synthesise insulin?
9-11 weeks
What problems does macrosomia cause?
Problems in labour
Increased risk of stillbirth
Caesarean section oft needed
How much urine does the fetal bladder produce at term?
500-700ml per day
How often does the fetal bladder fill and empty?
Every 20-30 min
What is the:
a) Cardiac output to kidneys
b) GFR
in a fetus compared to an adult?
a) 3% (25% in adult)
b) 50% of an adults
Why is fetus urine dilute?
Kidney x concentrate urine due immature ADH
What are the contents of the amniotic fluid?
Urine Amniotic membrane secretions Fetal lung secretions Salivary secretions Fetal epithelial cells,amniotic cells,dermal fibroblasts
What structure prevents blood from flowing through fetal liver?
Ductus venosus
What is the fetal circulatory response to hypoxia?
Heart rate falls
Resistance in umbilical artery increases
Resistance in middle cerebral artery decreases, protecting flow to fetal brain
Blood flow increased to heart + adrenals
Blood flow reduced to kidneys producing oligohydramnios
What cardiac changes occur to baby during delivery of baby?
Cord occlusion decreases right atrial pressure, foramen ovale closes
Inspiration causes vasodilation of pulmonary
artery + decreased resistance in pulmonary
circulation, reducing flow through foramen ovale + ductus arteriosus
What does pulmonary surfactant contain?
When is is secreted in fetus?
70-80% phospholipids
10% protein
10% cholesterol
From 30 weeks
What hormone supplement can be given to mothers in premature labour/delivery to help fetal lung development?
What does the hormone do?
Glucocorticoids (usu late pregnancy rise in cortisol)
Stimulates surfactant synthesis + secretion
Epithelial cell differentiation
Lung liquid reabsorption
Increases activity of antioxidants
When does HbF start switching to HbA?
What is the ratio at birth?
28 weeks
HbF:HbA ==> 80:20
What changes happen at delivery when baby has 1st breath?
Pulmonary vascular resistance drops 8-fold partly due to increased arterial pO2
Gas exchange commences
Lung Liquid secretion stops + liquid cleared
Surfactant secretion continues
What is the average amount of weight a mother will gain during pregnancy?
30 lbs/ 13kg
What injuries can the fetus face if it is too big?
Shoulder dystocia Brachial plexus injury Clavicular/humeral fractures Cephalohematoma Subdural hemorrhage Facial palsy
What happens to maternal RBC during pregnancy?
Synthesis increases, stimulated by erythropoietin
No increases but apparent anemia due to dilution
Haematocrit falls from approx 40% - 32%
What happens to DPG levels in a pregnant woman?
Approx 30% increase, facilitate offload of O2 release to fetus
Why do most water soluble vitamins decrease during pregnancy?
Mother’s blood volume increases so get diluted
How does hCG stimulate maternal thyroid activity?
Binds to TSH receptors of thyroid cells
LH-hCG receptor is expressed in thyroid
Possibly stimulates thyroid activity via LH hCG receptor + TSH receptor
What are 3 metabolic actions of human placental lactogen (hPL)?
Maternal lipolysis + increase in maternal (NEFAs) -
Anti-insulin action - increase in maternal insulin
Potent angiogenic hormone - role in formation of fetal vasculature
What is function of leptin in pregnancy?
Stimulates placental AA/FA transport
Where is leptin:
a) Synthesised?
b) Secreted?
a) Early embryo
b) Cytotrophoblast cells + syncytiotrophoblast
What causes peripheral resistance (+ BP) to fall
in pregnancy?
Increased vascular endothelial nitric oxide synthesis
Increased endothelial prostacyclin synthesis
Increased compliance of vessels due to structural changes
What pulmonary changes occur during pregnancy?
Tidal volume increases
Deep breathing stimulated by progesterone
Respiratory rate unchanged
Expiratory reserve reduced
pCO2 decreases, pO2 increases, pH unchanged (HCO3 falls)
Costal margin + diaphragm altered
What is the difference between:
a) Gestational age?
b) Embryonic age?
a) Used clinically, time 0 = 1st day of LMP
b) Used embryology, time 0 = fertilisation
What are the 3 stages of implantation in pregnancy?
Apposition
Attachment
Penetration
What is the primitive placenta made up of?
What does it split into?
Primitive Trophoblast
Cytotrophoblast layer - inner layer of mononuclear cells
Syncytiotrophoblast - outer layer of multinucleated cells
What are the 2 components of the placenta once it’s fully developed and what are they formed by?
Maternal portion - decidual plate
Fetal portion - chorion frondosum
What are the 3 stages of embryo growth + fetal patterns?
Stage I - hyperplasia
Stage II - hyperplasia + hypertrophy
Stage III - hypertrophy
When does most fetal weight gain occur?
95% of fetal weight gain occurs during 2nd half of pregnancy
What measurements of the fetus are taken during the ultrasound in the second trimester to asses fetal growth?
Head Circumference (HC) Bi-Parietal Diameter (BPD) Abdominal Circumference (AC) Femur Length (FL) Combine to estimate fetal weight (EFW)
When is antenatal screening for sickle cell and thalassaemia offered and how is it carried out?
Preconception - 10 weeks
Blood test
When is antenatal screening for infectious disease offered and how is it carried out?
(examples of disease?)
At booking
Serology
HIV, Herpes, Syphilis
How is screening performed for chromosome abnormalities?
Combined test:
Fetal nuchal translucency
Maternal serum βHCG
Maternal serum PAPP_A
When is antenatal screening for fetal anomalies offered and how is it carried out?
Between 18-22 weeks
Ultrasound
What is the definition of maternal death?
Death during/up to 6 weeks after end of pregnancy
‘Late’ maternal death covers period from 6 weeks postpartum until 12 months after end of pregnancy
What are the 4 categories that cause maternal death?
Direct: due to pregnancy-induced condition
Indirect: due to condition X caused by pregnancy but may have exacerbated it
Unspecified
Incidental: due to external forces
Definition of maternal near miss
A woman who nearly died but survived a complication that occurred during pregnancy, childbirth/within 42 days of termination of pregnancy
Does peak respiratory flow rate change during pregnancy?
No, if it does could be linked to asthma
How much folic acid should a woman take if they’re planning a pregnancy?
How many months prior to conception should they start taking it?
How much should be taken if the woman has a higher risk of neural tube defects?
400mcg
3 months
5 mg
What is:
a) Meiotic error?
b) Mitotic error?
a) Abnormal gametes arise
b) Germline - gonadal mosaicism
Embryo - mosaic embryo
What are the common chromosomes that fuse during robertsonian translocations?
13:14 - 75%
then 14:21 - 10%
What pregnancy risk do female carriers of 14:21 have? (In Robertsonian translocation)
15% risk of trisomy 21 pregnancy
What is QF-PCR in prenatal screening?
Quantitative Fluorescent PCR
Microsatellite markers used to identify + count chromos 13, 18, 21, X/Y
How is array CGH analysis carried out?
Compares 2 complete genomes
Detects differences in copy no across entire genome
What is measured in the combined test for Down’s syndrome?
Maternal age
Measurement of nuchal translucency (12 week scan)
Gestational age from length of fetus (CRL length)
Level of PAPP-A + free B-hCG in maternal blood
How are the hormone levels affected in Down syndrome?
PAPP-A commonly decreased in T13, 18 + 21
Free β-hCG commonly increased in T21 + decreased
in T13 + 18
What is measured in the quadruple test for Down’s syndrome?
Alpha-fetoprotein (AFP)
Human chorionic gonadotropin (hCG)
Unconjugated estriol (uE3)
Inhibin A
What happens during the 1st stages of labour?
Days: Contractions develop + cervix softens
Hours :Regular contractions - 3 erry 10 min), dilation of cervix (3-4cm -10cm)
Oxytocin can be given to help
What happens during the 2nd stage of labour?
Cervix fully dilated - 10 cm
Strong propulsive contractions - 1-2 hours
What is the puerperium stage of pregnancy?
Time from end of 3rd stage through 1st few weeks after delivery, as woman’s body returns to non-pregnant state (usu 6-8 weeks)
AKA postnatal/postpartum
What are the prenatal effects on brain formation in weeks 3-4? (what defects occur?)
Affects induction dorsally
Myelomeningocele (spina bifida)
Genetic/nutritional
Motor + perceptual defects
What are the prenatal effects on brain formation in weeks 5-6? (what defects occur?)
Affects induction ventrally
Holoprosencephaly - failure form 2 hemispheres
Oft genetic origin
Usu incompatible with life
What are the prenatal effects on brain formation in months 2-5? (what defects occur?)
Affects proliferation
Microcephaly - early cessation cell division => abnormally small head
Genetic/trauma factors e.g. infection, fetal alcohol syndrome
Low intellectual abilities
What are the 4 developmental domains of childhood development?
Gross motor
Fine motor + vision
Hearing + language
Social + emotional
What are the 5 stages of language development?
Preverbal communication Phonological development Semantic development Syntax + grammar development Pragmatics development
What are the 4 key concepts of developing cognitive skills?
Scheme - internal cognitive structure, provides procedure to use in specific circumstances
Assimilation - process of using scheme to make sense of event/experience
Accommodation - changing scheme cos of new info
Equilibration - process of balancing assimilation + accommodation to create schemes that fit environ
What is the 1st main stage of developing cognitive skills?
Sensorimotor, 0-2 yrs
Initial reflexes via sensory motor schema.
Child interacts with environ + manipulates objects
Understanding of object permanence
What is the 2nd main stage of developing cognitive skills?
Preoperational, 2-6/7 yrs
Internal representation of concrete objects + situations
Child uses symbolic schemes like language
Ego-centric
Reasoning dominated by perception
What is the 3rd main stage of developing cognitive skills?
Concrete operations, 6/7 – 11/12 yrs
Reasoning involves >1 salient feature (conservation)
Logical reasoning only be applied to objects real/can be seen
What is the 4th main stage of developing cognitive skills?
Formal operations, 11/12 yrs +
Think logically about potential events/abstract ideas
Test hypotheses about hypothetical events
Definition of epigenetics?
Chem modifications to DNA + DNA-associated structures BUT X change DNA sequence
Can regulate gene expression + be inherited across mitotic cell division
How does DNA methylation occur?
Addition of Ch3 group onto 5th carbon
5 methylcytosine (5mC)
Methyltransferase enzyme
Definition of gonadarche?
Activation of gonads by pituitary hormones FSH-LH
Definition of adrenarche?
Increase production of androgens by adrenal cortex
Definition of thelarche?
Appearance of breast tissue, cause oestradiol (ovaries)
Definition of menarche?
1st menstrual bleed
Oestradiol on endometrial lining
Non ovulatory
Definition of spermarche?
1st sperm production
Nocturnal sperm emissions
FSH, LH ==> testosterone
Definition of pubarche?
Appearance of pubic hair ==> Androgens from adrenal gland
1st appearance of axillary hair, apocrine body odour + acne
What hormone starts puberty?
Surge in GnRH
What are some features of true central precocious puberty?
Gonadotropin dependent Early maturation of the HPG axis Sequential maturation Pathologic 40-75% of boys Pathologic in 10-20% of girls Sexual characteristics appropriate for child’s gender
What is the sequential order of puberty for girls?
Adrenarche, Gonadarche, Breast development (thelarche), Growth spurt, Auxiliary + Pubic hair (pubarche), Menarche
What is the sequential order of puberty for boys?
Adrenarche, Testicular enlargement (gonadarche), Auxiliary + Pubic hair (pubarche), Growth spurt, Facial hair, (androgenic hair growth) Voice deepening
What hormone does prolactin inhibit?
GnRH
Both acromegaly and hypothyroidism have symptoms of weight gain. How would you distinguish between them?
Acromegaly - facial features, unable to fit into clothes at all
Hypothyroidism - trunkal obesity e.g. can’t fit into jeans
What is the function of aldosterone?
Acts principal cells of kidneys to reduce K+ + increase Na+
Acts ATP pumps of nephrons to absorb bicarb - increases pH
Release controlled by RAAS
What is the function of cortisol?
Promotes gluconeogenesis
Increase glc
Released in response stress, low BG (blood glc)
In the development of the embryo, what is the name of the structure where the first cell differentiation takes place?
When does this occur?
Morula
4 days
On weight and height charts for babies, why is there not a measurement recorded in 0-2 weeks?
Natural weight loss as baby energy expenditure increases as it gets used to life outside the womb
Singular measurement doesn’t tell you if baby gaining lost weight or actually growing
What measurements on a growth chart prompts an investigation?
Measurements that drop off 2/more centiles
Single measurements below 0.4 centile/above 99th centile
