Unit 1 - Parturition & Reproductive technologies Flashcards by Imogen Brown

What does Partuition require?

Signal from foetus
Cervical Softening
Co-ordinated myometrial contractions

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What occurs in stage one of Parturition? How long does this last?

(2-6 hours)

regular uterine contractions
cervical shortening and dilation occurs

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What is a latent phase of cervical dilation? How is this different from active phase?

latent- slow dilation

active- rapid dilation

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What occurs in stage two of Parturition? How long does this stage last?

(30-120 mins)

complete delivery of foetus, rupture of membranes and abdominal contractions

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What occurs in stage three of Parturition? How long does this stage last?

(5-8 hours)

Delivery of placenta

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What is hypertrophy in relation to Parturition?

oestrogen stimulates the muscle cell size to increase

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How does the myometrium contract? (4 steps)

spontaneous depolarizing pacemaker potential occurs
when the magnitude of these potentials is higher than the critical threshold a burst of action potentials occur
intracellular calcium increases in the extracellular fluid and endoplasmic reticulum
the calcium binds to regulatory sites on actin & myosin, allowing expression of ATPase & causing contractions

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What is Brachystasis?

Which cells undergo this process?

when contractions retract the lower uterine segment at the cervix to create a birth canal.
Myometrial cells

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What is the junction between the upper and lower segments of a uterus called?

Retraction Ring

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What is the role of hormones in Contractions?

Oxytocin lowers excitation threshold of muscle cells

Prostaglandins stimulate liberation of Calcium from intracellular stores

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How is Oxytocin regulated?

What does it lead to?

synthesised in the hypothalamus and transported axonally to the posterior pituitary.
Released in response to the stimulation of the cervix by the foetus
Leads to..
Myometrial contraction (+ve feedback loop)
Prostaglandin release

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What is the Fergusson reflex?

contraction initiated by pressure at the cervix or vaginal walls

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What is Primary Uterine Inertia? What is is caused by?

failure to initiate contractions at start of parturition

caused by lack of oxytocin

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What is secondary uterine inertia?

When is this most common?

uterine contractions at start, uterus then becomes fatigued and therefore contractions stop.
Common in large litters

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Cervical softening involves what three things?

reduction of collagen fibres
increase in proteoglycan matrix fibres
endocrine control

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What hormone is involved in Cervical Softening?

Prostaglandins - breakdowns collagen & stimulate uterine contractions

What is Ring Womb?

What is it caused by?

failure of the cervix to soften despite uterine contractions being normal
Caused by -
lack of prostaglandin
also linked to selenium deficiency

How is a Vaginal/ Uterine prolapse treated?

Vulva suture, prolapse harness or cull after parturition

How is Parturition started in Sheep? [what hormones are involved?]

Foetus becomes stressed and releases ACTH (adrenocorticotropic hormone) leading to cortisol increase
Rise in cortical leads to decrease in progesterone

What is ART technology? What is the purpose of it?

Assisted Reproductive Technology

increase chances of fertilisation & achieve pregnancy

What are the 6 steps of IVF (in-vitro fertilisation)?

Superovulation
Egg retrieved from ovary
Semen Collection
Insemination & Embryo Culture
Embryo Transfer
Luteal Support

What does Superovulation mean?

What are some side effects of this?

ovary is stimulated to produce multiple follicles using FSH & LH

IVF drugs linked to ovarian cancer (but infertile women are predisposed to develop cancer)
ovarian hyperstimulation syndrome

How is an ultrasound used in IVF?

Hint- used mainly in egg retrieving

Use transvaginal ultrasound to monitor follicular development
oocytes are then aspirated by ultrasound guided catheter

Once an egg is fertilised in vitro (in IVF) it is allowed to mature up to…….

4-8 cell stage using maturation media

What does Luteal support in IVF consist of?

administration of medication (particularly those that help maintain the Corus Luteum e.g. Progesterone)

What is Intra-Cytoplasmic Sperm Injection?

modified IVF technique | sperm injected directly into oocyte so higher success rates

When is Intra Cytoplasmic Sperm Injection used?

If sperm is unable to fertilise due to abnormal morphology, motility or damaged acrosome

What is Pre- implantation Genetic Diagnosis?

screens embryos for genetic disease e.g. sickle cell anaemia, cystic fibrosis

What is the Method for Pre-Implantation Genetic Diagnosis?

1. Patient undergoes a routine IVF treatment & embryo matures to 8 cell stage 2. A sharp pipette is used to break through the Zona Pellucida to suck up blastomere (known as Zona Drilling). 3. Blastomere is broken down to get the genetic content & test for markers of genetic conditions.

Why is Mitochondrial Donation performed before IVF in some cases?

defects in mitochondrial DNA affect how cells use energy

How does Mitochondrial Donation work?

1. Remove the nucleus from a harvested oocyte 2. Remove and discard the nucleus from a donors oocyte (healthy mitochondria) 3. Insert the patients nucleus into the donor oocyte 4. Fertilise the oocyte with sperm (IVF or ICSI) and implant into patient

What is gene editing?

form of genetic engineering, enables identification, removal and replacement of 'faulty' genes

What is CRISPR-Cas9?

restriction enzyme complex used in gene editing to edit human germ line

How does CRISPR-Cas9?

1. Disable/ insert DNA into an embryo 2. CRISPR RNA sequence is generated to reflect the sequence of a target gene using Cas9 as the restriction enzyme 3. The CRISPR-Cas9 complex is introduced to the embryo 4. The target sequence is snipped out of cellular DNA and the synthetic DNA can be introduced.

How can CRISPR-Cas9 be applied to agriculture/ farming?

``` Aqua Advantage Salmon- twice growth rate & consume less food Muscle Mass (Cows)- embryos edited to double muscle mass ```

How can gene editing be used in organ transplantation?

CRISPR-Cas9 can be used to remove disease (PERV- Porcine Endogenous Retrovirus) in pig kidneys and lungs

What is the uses of Stem Cell Transplantation in Infertility treatments?

Can introduce Spermatogonial stem cells (SSC's) into a host testis when host does not make his own sperm or testis

What are the advantages of Stem Cell Transplantation in Infertility?

- preserve endangered species - can be used to breed from an animal after its death - reintroduce fertility in cancer survivors

How does Stem Cell Transplantation in relation to Infertility work?

[Spermatogonia stem cells divide asymmetrically- 1 cell enters spermatogenesis & 1 cell replaces the stem cell pool] 1. Isolate the Spermatogonia using surface proteins 2. Multiply these in cell culture 3. Transplant the stem cells into the testis via the rete testis or vas efferentia.