All of RDA Flashcards
Summaris the hormonal axis of the male repoductive system
GnRH
LH/FSH
- LH stimmulates Testosterone production from the Leydig cells
- FHS together with Testosterone acts on Sertori cells
- produce Sperm from Germ cells
- produce inhibin
Both Testosterone and Inhibin have a -ve feedback on Hypothalamus and Pituitary
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/019/a_image_thumb.png?1586934786)
What is the epidymis?
Part where Sperm Are stored before being ejeculated
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/020/a_image_thumb.png?1586934787)
Where does spermatogenesis occur?
What are the main cells involved?
It takes place in the Seminiferous tubule, cells pass from outsid to in for ripe sperm cells
- Sertoni cells= grey
- Leydic cells= associated
- spermatogonia are the visible cells
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/021/a_image_thumb.png?1586934788)
Explain the cyclical changes in the feedback loop of the femaly reproducive system
Oestrogen has an
- inhibiting role in first part of cycle
- enhancing (+ve feedback) for mid cycle (triggers ovulation)
And Progesterone has generally
- -ve feedback on hypothalamic Pituitary axis
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/022/a_image_thumb.png?1586934789)
Explain the process of male ejaculation
At ejaculation
- sperm pass from epidymis through
- the two Vas Deferens (which are contractile),
- mixed with fluid from the seminal vesicles
- leaves the ejaculatory duct,
- and passes into the urethra where it
- mixes with secretions from the prostate gland.
Summarist the circulating steroid hormonal changes and LH/FSH changes in the female cycle
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/023/a_image_thumb.png?1586934790)
Explain the changes in the endometrial lining during the menstrual cycle
- Thickening from 2-3mm to 7-16mm in first 3/4 (Etrogen only)
- imlantation happens at maximal thickness
- Menstruation (shedding of Endometrium) –> E2+ Progesterone
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/024/a_image_thumb.png?1586934791)
Summarist the stages of Follicuogenensis and its timing
- Primary follicle with primary oocyte starts to form
- Growing follicle
- Antral Ovum
- Oculation
- Formation of Corpus Luteum
- Degradation of Corpus Luteum
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/025/a_image_thumb.png?1586934792)
Happens over 3 Months! Several eggs in both ovaries
Which neuroendocrine system is involved in Reward and pleasure?
The mesolimbis dopaminergic pathway
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/026/a_image_thumb.png?1586934794)
Which neuroendocrine system is involved regulation of fertility and parenting?
Hypothalamus to pituitary
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/027/a_image_thumb.png?1586934795)
Explain the role of FSH in femal reproduction
•FSH stimulates (some) development of ovarian follicles & 17b-estradiol synthesis
Explain the role of LH in female reproduction
•LH stimulates progesterone production
+ acts on thecal cells to stimmulate androgen production (converted to oestregen by granulosa cells under influence of FSH)
Explain the precess of oogenesis
- 1st mitotic devison happens in utero
- Cell reusmes with 2nd mitotic devision when it ripenes –> 2 month before Menstrutation
- BUT: stops at Metaphase II at ovulation
- Only resume with Fertilisation!
Differentiate between sexual reproduction, sexual intercourse and biological sex
Definitions
Sexual reproduction – produce genetically different offspring.
Sexual intercourse – required for – sexual reproduction, sexual activity, sexual pleasure, human bonding.
Biological sex – identifies gender, a result of chromosomes, produces different gametes.
What are the changes to the penis that occur during erection?
- Initiated by: increased parasympathetic activity to smooth muscle of pudendal artery
- increase in NO
- NO–> increases cGMP –> dilatation of arterial smooth muscle.
- counteracts sympathetic-maintained myogenic tone
- increases blood flow in corpus cavernosum
- which compresses the dorsal vein, restricting the outflow of blood
- The urethra is protected from increased pressure by surrounding corpus spongiosum (less turgid)
What are the Risk of pregnancies in the first trimester?
There is a high risk of miscarriage, often due to
- placental abnormalities
- chromosomal abnormalitiesof the foetus
*
What are the features of the first trimestern in pregnancy for the mother?
- Altered brain function [1st & later]
- Altered emotional state [1st & laterr
- due to: Altered hormones [1st & later]
- Altered appetite (quantity and quality) [1st & later] – GI imbalance
- Altered immune system [1st & later]
What are the main changes that happen to the mother during the 2nd trimester of pregnancy?
- Altered fluid balance [2nd & later]
- Increased blood volume [2nd & later]
- Increased blood clotting tendency [2nd & later]
- Decreased blood pressure [2nd]
+ all changes from 1st trimester
What are the main maternal changes in the 3rd trimester?
Increased weight [3rd]
Altered joints [3rd]
–> plus symptoms from 1st and 2nd trimester
Explain the differentiation and characteristics of the trimesters of pregnancy
- 0-13 Weeks
- High risk of miscarriage
- 13-26 Weeks
- (Barely) no viability if delivery before that
- 26-40 Weeks
- Term, viable outside uterus
Summarise the hormonal changes during Pregnancy
Overall: very very high hormone levels
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/050/a_image_thumb.png?1586934810)
What are the main maternal risks of Pregnancy?
Generally: Low risk except delivery itself (risk of bleeding)
What is a conceptus?
Conceptus – everything resulting from the fertilised egg (baby, placenta, fetal membranes, umbilical cord)
What is an embryo?
Embryo – the baby before it is clearly human Ca. 0-9ssw
What is a fetus?
Fetus – the baby for the rest of pregnancy (clearly human and not just an embryo)
When does Pregnancy start?
Normally counted as the first day of the last menstrual cycle
- because ovulation is difficult to determine (expecially with infrequent periods etc)
But embryologist would start at time of conception/fertilisation
What is the source of the high levels of progesterone in pregnancy?
0-8 Weeks: Corpus Luteum
After 10 Weeks: Placental produces all progesteone
–> Called: ‘luteo-placental shift’
Steroidogenesis: recognise pregnancy as a three-way interaction between mother, fetus and placenta with steroidogenesis as an example of this
The human placenta does not express the enzyme (Cytochrome P450 17A1, or CYP 17, or Cytochrome P450 17,20-lyase) that converts pregnenolone to androgens, so this part of biosynthesis takes place in the fetal adrenals (which are large and well-developed even in the first trimester). The weak androgen produced (dehydroepiandrosterone, DHEA) is sulphated as well to give DHEA-S, which is inactive. Hence a female fetus is not exposed to an androgen during development. The DHEA-S circulates to the placenta, where it is converted to 17beta-oestradiol as shown.
In human pregnancy, very high levels of oestriol are found, which are produced by a parallel mechanism (Figure 3.5), which includes hydroxylation of DHEA-S in the fetal liver to produce the precursor 16OH-DHEA-S.
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/051/a_image_thumb.png?1586934812)
What are the sources of the high oestrogen levels in pregnancy?
Early Weeks: Corpus Luteum
Then: Shift to
- Maternal adrenals
- Placenta
- And Fetal Adrenals/Liver
Explain the immunological changes durig pregnancy
Need to tolerate foreign Baby
- downregulation of maternal immune system
- HLA (almost invariant) expression on Placenta
What is the implication of the different counting of pregnancy (fertilisation and LMB)
Normally not relevant at full term but important in early development (or when deciding, whether fetus viable or not)
What is the main structural (and functional) unit of the placenta?
Cotyledons (structural SU with groovs inbetween that are filled with maternal tissue)
- One cotyledon can have one or several villi (placental villous trees)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/052/a_image_thumb.png?1586934813)
Explain the basic structure of a placental villous tree
Structure that allows exchange between maternal and fetal circulation
- it has one main branch
- with many small branches coming off again
- complex blood supply, including arterial and venous vessels, connected to smaller capillaries in the terminal portions of each villus
- huge surface area
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/053/a_image_thumb.png?1586934815)
What is the state of the placenta 9 days post fertilisation?
The conceptus is almost fully implanted
- Placenta will form from Cytotrophoblast
- Proliferate under layer of syncytiotrophoblast, which contain fluid-filled lacunae
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/054/a_image_thumb.png?1586934816)
What happens to placental development after implantation?
cytotrophoblast proliferate into the syncytium
- first a columnar structure is formed (cytotrophoblast column),
- which then undergoes branching (villous sprouts).
- At the centre of each villus are mesenchymal (extra-embryonic mesoderm) cells, from which the villus vascular system develops.
- –> Further Branching later in pregnancy
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/055/a_image_thumb.png?1586934818)
What is the cytotrophoblast shell?
Shell that is formed around the developing fetus that minimised exchange between Fetus and Mother
- To protect fetus (e.g. from free oxygen radicals) (fetus is cery vulnerable during that time)
- Achieved via cytotrophoblast plugs that block spiral arteries
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/056/a_image_thumb.png?1586934819)
What are Spiral arteries?
Are modulated wide, maternal arteries without SM layer or endoethelial layer but replacement with cytotrophoblast cells –> no contraction and allows constant high Blood flow to Baby
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/057/a_image_thumb.png?1586934820)
What is a Teratogens
A substance that can interfere with normal embryological development
What are the functions of the placenta?
-
Exchange
- of nutrients (maternal to fetal) and waste products (fetal to maternal)
- Between the vascular systems of the mother and embryo or fetus.
-
Connection (or anchorage)
- to keep the fetus and the connection to maternal blood vessels intact
-
Separation
- e.g. to not cause rejection, etc.
-
Biosynthesis
- very active, e.g. in hormone production etc.
- Immunoregulation
What is the main nutritional supply of the fetus in the first 10 Weeks of Pregnancy? How does it change after that?
First 10 Weeks
- via decidual glands (hypertrophy) –> supply with glands: histotrophic nutrition
After 10 Weeks:
- Maternal blood (haemotrophic nutrition) will supply nutrients
What might happen during the junction of the fetal and maternal circulation?
There is an increased risk of miscarriage (late first trimester) due to
- the placenta is not fully anchored to maternal decidua but
- the increase in pressure as it is exposed to the maternal arterial supply can detach the placenta
How is regulation of placental growth achieved?
Autocrine regluation by Placenta itself
What are the consequences of placental mal-development?
- Miscarriage (late first trimester + 2nd trimester)
- Pre-eclampsia (early delivery)
- Fetal growth restriction (small infant)
What is Stillbirth?
Stillbirth refers to the death of an infant within the uterus, so that it is delivered without any signs of life
Hard to define (age wise), viability can be used as indicator (before that: miscarriage)
What are counted as term deliveries?
Deliveries between 37 and 41 Weeks of Pregnancy
When do post-term deliveries take place?
After 42 Weeks of pregnancy
When do pre-term deliveries take place?
How can you differentiate?
Pre-term= deliveries between 22-37 weeks
- Extremely preterm
- 22-28 weeks
- Very preterm
- 28-32 weeks
- Moderate to late preterm
- 32-36 weeks
What are misscarriages?
How can you distinguish between them?
Miscarriage: Less than 22 weeks (non viable infant delivered).
- Early miscarriage
- First trimester (common, often due to problems in anchoring and vascular formation)
- Late miscarriage
- Second trimester less than 22 weeks
What are the key tissues involved in Labour?
- The mxometrium
- Cervix and the
- Fetal membranes
What is the clinical definition of labour?
Fundally dominant contractions
- coordinated contraction of the myometrium combined with
Cervical ripening & effacement
- change in cervical structure –> softens
Also involved:
- Rupture of fetal membranes
- Delivery of infant
- Delivery of placenta
What is the latent stage (of labour?)
It is the stage about 8 weeks prior to delivery myometrial remoddeling (+ practice contractions) happen
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/072/a_image_thumb.png?1586934833)
What happens in the three stages of labour?
How long do they take?
- Stage 1= Contractions, cervical changes (usually rupture of fetal membranes) (variable, many hours)
- Stage 2= Baby delivered (hours)
- Stage 3= delivery of placenta (around 30 min)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/073/a_image_thumb.png?1586934834)
What are factors that might trigger preterm initiation of labour?
- Intrauterine infection
- activation of inflammatory cascade (NF-kß)
- Intrauterine bleeding
- Multiple pregnancy
- Stress (maternal)
- Others
Which factors initiate full term labour in humans?
–Not really sure!!!
–Estrogens; low progesterone?; CRH?; oxytocin?
What happens during cervical ripening and effacement in labour?
It is an inflammatory change!!
- Change from rigid to flexible structure
- Remodelling (loss) of extracellular matrix
- Recruitment of leukocytes (neutrophils)
- Inflammatory process
- Prostaglandin E2, interleukin-8
- Local (paracrine) change in IL-8
Explain the key characteristics and that happen to the endometrium during labour and the most important mediators
- Fundal dominance
- Increased co-ordination and power of contractions
- Key mediators
- Prostaglandin F2a (E2) levels increased from fetal membranes
- Oxytocin receptor increased
- Contraction associated proteins
What is involution?
What is its significance?
It is tue poweful contraction of the uterus after delivery of the placenta
–> prevents mother from bleeding to death
What happens to the fetal membranes during labour?
What are the key mediators?
Also Inflammatory
- Rupture of fetal membranes
- Loss of strength due to changes in amnion basement component
- Inflammatory changes, leukocyte recruitment
- Modest in normal labour, exacerbated in preterm labour
- Increased levels and activity of MMPs (matrix Metalloproteases)
- PGs and interleukins
Explain the role of Platelet-activating factor
It is a fetal signal of maturity that might lead to initiation of Labour (via upregulation of inflammatory processes)
- Part of lung surfactant
- Produced by maturing lung, before birth
- Increased levels before birth
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/074/a_image_thumb.png?1586934835)
Explain the role of CRH in labour
CRH up-regulate inflammatory pathways in fetal membranes via stimmulation of Progesterones and IL
- Maternal CRH causes production of fetal corticosteroids leading to
- +ve feedback of CRH production in the placenta
- Production of Estrogens (leading to further modulation e.g. in oxytocin receptors)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/075/a_image_thumb.png?1586934836)
Explain the role of Progesterone in labour
Thought to possibel initiate labour
- High levels are needed to keep pregnancy
- High levels of Progesterone Receptors inhibit NF-kB during pregnancy leading to
- lower levels of inflammation
- At term: less of Progesterone Receptors B (that are the main mediators of levels of progesterone in comparison to PR A can mediate the reponse less)
- Activation of NF-kB
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/076/a_image_thumb.png?1586934838)
Which biochemical pathways of labour are affected by progesterone?
Via the increase expression of NF-kB
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/077/a_image_thumb.png?1586934839)
Explain how examination of the cervix is used to assess the progress of labour
- The cervix must be 10 cm dilated and 100% effaced (thinned out) for delivery (can be felt)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/078/a_image_thumb.png?1586934839)
What is the role of NF-kß in labour?
How is it activated?
Seems to be activated by many initiators of laborur
And is the main regulator, driver of labour
- +ve feedback loop (causes inflammation and inflammation causes expression of NF-kß)
*
What does activation of NF-kB lead to?
It is a Transcription factor
- binds to promoters of pro-labour gene
- upregulation of these genes and driving of inflammation leading to expression of
- COX-2 (prostaglandins - PGs),
- IL-8, IL-1b,
- MMPs,
- Oxytocin and PG
- contraction-associated proteins
- upregulation of these genes and driving of inflammation leading to expression of
Explain the role of Platelet-activating factor
It is a fetal signal of maturity that might lead to initiation of Labour (via upregulation of inflammatory processes)
- Part of lung surfactant
- Produced by maturing lung, before birth
- Increased levels before birth
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/081/a_image_thumb.png?1586934859)
Explain the role of CRH in labour
CRH up-regulate inflammatory pathways in fetal membranes via stimmulation of Progesterones and IL
- Maternal CRH causes production of fetal corticosteroids leading to
- +ve feedback of CRH production in the placenta
- Production of Estrogens (leading to further modulation e.g. in oxytocin receptors)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/082/a_image_thumb.png?1586934859)
Explain the role of Progesterone in labour
Thought to possibel initiate labour
- High levels are needed to keep pregnancy
- High levels of Progesterone Receptors inhibit NF-kB during pregnancy leading to
- lower levels of inflammation
- At term: less of Progesterone Receptors B (that are the main mediators of levels of progesterone in comparison to PR A can mediate the reponse less)
- Activation of NF-kB
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/083/a_image_thumb.png?1586934861)
Which biochemical pathways of labour are affected by progesterone?
Via the increase expression of NF-kB
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/084/a_image_thumb.png?1586934861)
Explain how examination of the cervix is used to assess the progress of labour
- The cervix must be 10 cm dilated and 100% effaced (thinned out) for delivery (can be felt)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/085/a_image_thumb.png?1586934862)
What are the cellular processes that happen in embryology?
They overall function the exact same as other cells
Everything also happens via
- proliferation
- differentiation
- reorganisation and
- apoptosis
What happes during the first two month of human development?
Mainly lay down of all important organs
After 8 Weeks: mainly growth and elaboration of the structures that develop during the first two months
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/108/a_image_thumb.png?1586934878)
What happens to the fertilised egg in the Preimplantation state?
Preimplantation about 6 days
- Serious of cleavage –> Every time doubeling the cell number
- Egg develops into a Morula (=ball of undifferentiated cells)
- Differentiates so outer cells differ from inner cells
- Develops into a Balastocyte
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/109/a_image_thumb.png?1586934880)
Explain the structure of a Blastocyst
structure that has an
outer layer of trophectoderm (surrounded by zona pellucida)
, an inner cell mass,
and a fluid-filled cavity.
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/110/a_image_thumb.png?1586934880)
What is gastulation?
When does it occur?
14-18 days postfertilisation
which converts the bilayer of hypoblast and epiblast cells into a trilaminar embryo,
containing the three layers of Germ Cells
- (Ectoderm,
- Mesoderm and
- Endoderm),
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/111/a_image_thumb.png?1586934880)
Explain the process of gastrolation
- Epiblast cells proliferate and differentiate to form mesoderm cells
- These cells move to space between hypoblast and epiblast
- Mesoderm Cells differentiate and replace the hyoblast cells with endoderm cells
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/112/a_image_thumb.png?1586934881)
When does implantation take place?
How does is happen?
The blastocyst seperates from outer zona pellucida and merges with the uterine lining (finished at day 10)
How does a Blastocyst differentate further (during implantation)?
The inner cell mass ot blastocyte becoms a bilayer disk, composed of
- hypoblast and
- epiblast cells
–> This bilayer disk gives rise to all the tissues of the human fetus
What is Neurolation
What is it controlled by?
It is formation of the Neural tube (Brain + Spinal Chord) controlled by the Notocord (in the mesoderm)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/113/a_image_thumb.png?1586934882)
Explain the earyl process of neurolation
- Development of the neural plate
- It develops two folds
- They grow and meet over the neural groove
- to form the neural tube
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/114/a_image_thumb.png?1586934883)
When does the neural tube close?
Closing continues in Week four
- Cranial End about 22 days
- Rostral End about 23/24 days
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/115/a_image_thumb.png?1586934884)
Explain the process of embryological folding
When does this happen?
3-4 Weeks
- Tissues fold laterally and fuse in the ventral midline
- In anteroposterior direction
- Folds the primordial germ cells (PGCs) from caudal end into hindgut and heart progenitor cells under head of embryo
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/116/a_image_thumb.png?1586934884)
What is the state of the embryo at the End of Week 4?
Precursor of all internal organs have been laid down
External structures start to develop
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/117/a_image_thumb.png?1586934886)
Summarist the embryological development of the limbs
Occurs over a number of weeks
- Forelimb bud appears at d27/8
- Hindlimb bud at d29
- Grow out from lateral plate mesoderm rapidly under control of special signalling regions (+rotation etc)
- Fully formed and patterned by d56.
- develop further (finger differentiation)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/118/a_image_thumb.png?1586934887)
What controlls the pattern of digit development?
By the sonic Hedgehodge SHH protein in the:
The ZPA = Zone of Polarising activity
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/119/a_image_thumb.png?1586934888)
Explain the use of thalidomide (historically and present) and its complications
Historically: was used as treatment against morning sickenss in first trimester of pregnancy –> caused many deformations (not just limbs but also more organ systems)
- Now: As cancer treatment+ against leprosy
- it damages developing blood vessels, thus depriving the adjacent cells of nutrients and preventing their proper growth and development –> most seen in upper limb development
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/120/a_image_thumb.png?1586934888)
Summarist the development of the kidneys?
Closly interconected with genital formation
- Will develop from urogenital ridge in Mesoderm at around Week 4
- Pronephrons
- Week 4
- in cervical region of embryo
- get degraded around Week 6
- Mesonephrons
- develops caudally to pronephrons
- Month 2
- Metanephrons
- adult type of Kidney
- Apperars in 5th week of kidney, fully functional at 12th week
- Ascent from pelvic region to abdomen
- Pronephrons
–> Sequential development and degradation of pronephrons, mesonephrons and metanephrons
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/121/a_image_thumb.png?1586934889)
Explain the formation of the male reproducitve system
- Primordial germ cells migrate to the genital ridge on the nephrogenic chord (intermediated mesoderm)
- Form gondads, attached to mesonephric duct (Wolffian)
- surrounded by paramesonephric duct
Up to this point: sex is indistinguishable
Then
- SRY+ (on y chromosome)
- Maternal hCG binds to leydig cells –> induction of production of testosterone and Anti-mullerian Hormone
- AMH= regression of mullerian (paramesonephric) + formation of wolffian (mesonephric) system
- External Genitalia: Tostesterone
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/122/a_image_thumb.png?1586934890)
Explain the formation of the Female reproductive system
- Primordial germ cells migrate to the genital ridge on the nephrogenic chord (intermediated mesoderm)
- Form gondads, attached to mesonephric duct (Wolffian)
- surrounded by paramesonephric duct (Müllerian system)
Up to this point: indistinguishable
- Absence of SRY- and Testosterone
- formation of female tract of the pararmesonephric ducts and female external genitalia
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/123/a_image_thumb.png?1586934891)
What kind of tissues to mesoderm cells differntiate?
muscles, blood, skeleton, heart and kidney
What kind of tissues to ectoderm cells differntiate to?
Skin and CNS
Summarise the embryological development of the heart
- two heart tubes form which fuse to give rise to
- single heart tube (21 days post fertilisation)
- Complex Looping/Folding of Heart
4.
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/124/a_image_thumb.png?1586934892)
Explain the fetal circulation
Blood recieved from umbilical chord
goes through ductus venosus into IVC
to Right atrium
can go to left atrium via foramen ovale
Ductus arteriosum connects “pulmonary artery” directly to aorta
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/125/a_image_thumb.png?1586934893)
What are the most common cardiac abnormalities in developmen
Relativly common but can be severe
- often structual –> can be cured by surgery
- Most important: Septal defects
- But rare but might also occur: transposition of blood vessels
- e.g. aorta attached to right ventricle, pulmonary artery attahced to left ventricle
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/126/a_image_thumb.png?1586934894)
Which tissues to endoderm differentiate to?
Into
- Gut
- Lung
- Liver
But: Muscular and vascular tissue are generally of mesodermal origin, so tissues are normally a mixture of germ layer types (e.g. muscle in the skin and gut).
Summarist the process and timing of embryological facial development
Most structures are formes in first 5 Weeks (bilaterally!
Migrate and meet in centre (over a period of about 5 Weeks)
- Movement thought to happen via
- Cleft formation and loss of tissue
- Filling of cleft with migrating tissue
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/127/a_image_thumb.png?1586934894)
Explain the formation of a cleft lip
- Usually unilateral upper lip and palate
- Might be bilaterally (cleft lip)
- Or symmetrical (palatine cleft)
- because of the way they come together (picture)
- Developmental Error about Week 10
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/128/a_image_thumb.png?1586934895)
Identify the five stages of lung development and Identify the changes in structure that occur in these stages.
- Embryonic
- Bronchi form
- Pseudoglandular
- Bronchioles and terminal bronchioles form
- Cannicular
- Respiratory bronchioles form
- Saccular
- alveolar ducts form
- Alveolar stage
- alveolar sacs form
![](https://s3.amazonaws.com/brainscape-prod/system/cm/308/661/129/a_image_thumb.png?1586934896)
As overview: what happens during Month 2 of embryological develompent?
Mostly elaborate the tissues formed in first weeks
- urogenital
- cardiac
- facial
- lung development
+
- Limbs
Summarise the development of the gonads
Develop from: The gonads arise from intermediate mesoderm within the urogenital ridges of the embryo
- The genital ducts arise from paired mesonephric and paramesonephric ducts (up to 7 Weeks: no differentiation)
- Differential development of the male reproductive system is dependent on the activity of sex-determining region Y (SRY) protein, coded for by the SRY gene on the Y chromosome.
- The mesonephric ducts give rise to MALE genital ducts
- The paramesonephric ducts give rise to FEMALE genital ducts
What are the main causes that might lead to abnormal development of the male reproductive system?
- inability to produce Testosterone/ AMH (anti-mullerian hormone)
- inability of tissues to respond to the stimmuli
Name examples of disorders of the reproductive system
- Androgen Insensitivity Syndrome Variable phenotypes
- genetic mutation in androgen receptor
- external genitalia: female
- Internal genitalia
- mesonephric (Woolffian) ducts are rudimentary/ lacking
- no descending of testicles
- But: AMH normal: no female structures possible
- Congenital Adrenal Hyperplasia
- enzyme deficiency (endo) of cortisol production
- high ACTH
- overstimmulation of adrenals
- androgen production
- Partial virilisation of the external genitalia
- Internal genitalia: female
- enzyme deficiency (endo) of cortisol production
Explain the time and formation and risk factors of spina bifida
Defect in closing of neural tube (around day 21/22)
Occurs early in development
–> Many cases can be prevented with supply with folate acid
What is anencephaly?
When does this developmental defect originate?
No closure of the anterior neuropore
–> open skull and lack of part of the brain
Also at around 22 after fertilisation
When does surfactant production start?
What is its role in delivery and delivery of premature babies?
Production begins in early 3rd trimester of pregnancy and increases
- production needed for normal lung function at birth
- Can be accelerated by glucocorticoid injection
- ofte therefore: preterm babies suffer from lung complications (low surfactant production)
- might lead to Respiratory Destress syndrome
*
- might lead to Respiratory Destress syndrome
Where is most historical data about fetal growth from?
What is used today?
Historically: from miscariages (but problem: often fetus that have growth restiction are more likely to die)
Now: ultrasound