Urogenital Flashcards

Question

Why do sertoli and leydig cells secrete oestradiol?

Answer 1

Regulates absorption of fluid into epididymis, allowing sperm maturation

Answer 2

* Stabilise nucleus - Condensation of nuclear chromatin * Stabilise plasma membrane - Addition of surfave glycoproteins (decapacitation factors) * cAMP levels increased in tail =\> motility

Answer 3

* **SYBR-14** stains intact plasma membranse green * **Propidium iodide** stains sperm with damaged membranes red * Sperm pass a laser which excites fluorescent particles * These can either be **counted** or a assigned an **electric charge dependant on fluorescent at certain wavelengths** * IF electrical charge is assigned sperm can be assorted * Allows for sorted semen which are viable and sexed

Answer 4

* Cell is placed in argarose gel and lysed * Electrophoresis * Intact DNA fragments to large to move * Poor DNA integrity will cause large fragmentation

Answer 5

Progressive destabilisation of the plasma membrane * Glycoproteins coating sperm head removed, exposing ZP3 * Membrane fluidity increased to aid breakdown of acrosome * Mobilisation of intracellular Ca⁺² in acrosomal reason

Answer 6

* Increased intracellular Ca+2 =\> increased cAMP * occurs in oviduct at uretotubal junction, isthmus * Increased head movement, velocity curvilinear (VCL) & decrease linearity (LIV)

Answer 7

_Computer assisted semen analysis_ ## Footnote Use motility measurments to determine the fertility of semen

Answer 8

* Fusion of **sperm plasma membrane** and **outer acrosomal membrane** * Fusion causes **vesiculation** and release of **hyaluronidase** and **acrosin** which digests a whole in zona pellucida & sperm moves into **pervitelline space** * Equatorial segment exposed for oocyte fusion. **equatorial segment** binds to oocyte **plasma membrane**. * **Cortical granules** released to prevent pollyspermy

Answer 9

* **Chlortetracylcine** staining * Binds to intracellular Ca⁺² * When sperm is **capacitated fluoroscene free band** can be seen in post acrosomal region * When sperm has undergone **acrosome** reaction theres dull or **absent fluorescence in head**

Answer 10

* Prevents transportation of animals which is stressful * Global genetic selection possible * Selective breeding * Preservation of endangered species * Biosecurity (foot and mouth)

Answer 11

1. _Room temperature_ - Decreases the metabolic rate. diluted in **'extender' solution**, similiar composition to seminal plasma. lasts for **3-5 days**. Does not allow for period of quarentine or long term storage. commonly used with pigs 2. _Semen freezing_ - Stored in **liquid nitrogen at -196** degrees. Fertile for 10+ years. Can breed from animal after death. is unsuccesful in pigs.

Answer 12

* Male and female pronuclei fuse * **Cleavage** occurs, series of mitotic divisions up to **8 cell stage (blastomers)** * After 8 cell stage now morula stage * 2 distinc layers form, **ICM & trophoblast** * **Outer cell mass** pumps sodium (obligatory **water**) into blastocyst, forming **blastoceole** * **ICM** forms **embryo** & **trophoblast** form **placenta** * In uterus, blastocyt has to **digest** zona pellucida to **allow implantation**

Answer 13

The lungs are filled with prostaglandin hydrogenase which will break down any prostaglandins in systemic circulation. therefore when released, PGF2a can diffuse between blood vessels keeping local concentration high

Answer 14

* Luteal phase only occurs after mating * During **pseudo-pregnancy**, CL lasts **40-45 days**. But duration of **gestation** is **60 days**. therefore MRP is required * **Prolactin!**

Answer 15

**_Interferon tau_** Uterine horns were surgically seperated. One side was maintaint pregnancy and the other wasnt. In the pregnant horn, interferon tau levels were high and oxytocin receptors were low. in the non pregnanct side interferon tau levels were low and oxytocin receptors werre high.

Answer 16

* MRP is **_oestradio_**l, foetus required in each horn or PGF2a will be produced and terminate pregnancy * Oestradiol **redirects PGF2a synthesis** towards **endometrial lumen (exocrine)** instead of **diffusing into blood** (endocrine). **Fails to reach ovary** * PGF2a in lumen is either **metabolised** or causes **contraction**, allowing even **distribution of foetuses** in available space * Oestradiol also promotes production of **PGE₂**which **promotes P₄ secretions from CL**

Answer 17

* Normal mare cycle is 21 days * day 36-38 trophoblast migrates into endometrium , forming endometrial cups. These secrete eCG * Therefore cant be MRP because it would have been secreted before 21 days eCG along with FSH stimulates secondary ovulation. Forms accessory CL, supplements P₄until day 100 where placenta takes over

Answer 18

* day 3 - Embryo secretes PGE2, for oviduct transport * day 5 - Embryo enters uterus * day 10 - Conceptus secretes oestrogens. These cause secretions of PGF2a and PGE2, aid in uterine transport * day 15 - Increase in uterine tone, fixation of foetus * day 35 - Endometrial cup formation

Answer 19

1. **Primitive endoderm** moves down covering the trophoblast cells, forming the **yolk sac** 2. Downwards moving **mesoderm** along with **trophoectoderm** form the **chorion** 3. The **yolk sac** can make contact with the **trophoectoderm**, facilitating exchage. **_Choriovitelline placenta._** (*non mammals/marsuples)]* 4. **Allantois** is then formed (***out pouch** from the embryo*). Contains blood vessels and its function is to **exchange nutrients/waste** 5. **Allantois** fuses with **chorion** forming **allantochorion** This is a _chorioallantoic placenta._ formed by **ruminants, pigs & humans.** **Horses** and **carnivores** have a choriovitelline placenta and then a _chorioallantoic placenta_

Answer 20

1) _Fetal membranes present:_ * **Choriovitelline** - Non mammals * **Choriovitelline** to **chorioallantois** - Carnivores & horse * **Chorioallantois** - Ruminants, pigs & humans 2) _Grass shape:_ * **Discoid** - humans, rodent * **Cotyledonary** - ruminants * **Zonary** (ring) - Carnivores * **Diffuse** - pigs, equids 3) _Implantation_: * **Centra** - superficial -ungulates * **Eccentric** - semi implanted - carnivores 4) _Cell layers, maternal to foetal membrane_ * **6 layers** - *epithelialchorial* - ungulates * **4 layers** - *endothelialchorial* - carnivores * **2/3 layers** - *haemochorial* - human/rodents. Trophoblast cells invade maternal blood vessels 5) _Interdigitation at attachment points_ * **Folded** - Pigs * **Lamellar** - carnivore * **Villous** - equids, ruminants and humans

Answer 21

* Chorioallantoic * diffuse * central * epitheliocortical * folded A vascular necrotic tips

Answer 22

* Choriovitteline to chorioallantoic * Epitheliochorial * central * Diffuse * Villous Contain microscopic microcotyeldon. Can only cope with one foetus as it requires nutrients from the whole uterus. Will abort at 9 months.

Answer 23

* Chorioallantoic * Cotyledonary * Central * epitheliochorial * Villous

Answer 24

* Choriovitelline to chorioallantoic * Zonary * Eccentric * endothelialchorial a band of tissue around around conceptus

Answer 25

* Na⁺, K⁺, Cl^-, fatty acids, steroid, gas and urea move by **simple diffusion** * **Less soluble** molecules needed in large amounts for **facilitated diffusion**. e.g glucose. **Glucose** transporters **asymmetrically** distruted on **trophoectoderm** to **stop excretion** **out** of placenta. * Oxygen diffuses freely across placenta, rapidly reaching equilibrium. Equilibrium exploited by : 1. Fetal haemoglobin has **higher affinity** 2. Fetal blood contains **more haemoglobin** 3. Fetus to mother l**oss of C0₂ enhances 0₂ transfer** 4. Mother to fetus **0₂ loss causes increased affinity for C0₂** * Potentially toxic (I-), igG, Na+,K+,Cl- exchanged by **active transport**

Answer 26

* _Mare_ - Progesterone dependant secretions of **uteroferrin** * _Carnivores_ - **Seppage** of **RBC**'s from mother taken up by trophoblast

Answer 27

* _Physical_ - **Amnion** associated with fluid **cushion** * _Teratogens_ are **external** influences that induce **developmental abnormalities**. Either **non iatrogenic** (Microrganisms, radiation) & **iatrogenic** (tetracyclines)

Answer 28

1. _Fetal evasion_ - **Reduced** expression of **MHC class I** at fetal/maternal interface**. No MHC class II** 2. _Defence mechanism_ - Derive products that modulate local environment. E.g **ID**O, which **deplet**es tryptophan and **inhibits Tcell proliferation** 3. _Shift_ - **Progesterone** induced uterine proteins **suppress prolifertion** of **lymphocytes** in **ruminant** uterus

Answer 29

* _Progesterone_ (**DHP** secreted by mare at 210 days when P4 dips * *_eCG_* - highly glycosylated LH, long half life. Luetrophin, causes of 2nd ovulation/CL * _Oestrogens_ - Growth of myometrium, **Proliferation of endometrium** and **stimulates uterine blood flow** * _Placental lactogens_ - Produced by placenta in ruminants, humans and rodents. **Alters carbs/protein metabolism, mammary development and Luteotrophic** * _oPL_ - Production of **IGF-1** in mother. causing **insulin resistance**. Causes glucose intolerance increasing glucose absorption in fetus. increase lipolysis, proteolysis & ketogenesis. * _Relaxin_ - Release just **prior to parturition**. Causes **relaxation** of the **uterine ligaments**, cervical softening, expansion of birth canal & **mammary gland devlopment.**

Answer 30

* _Streak canal_ - Keep milk in udder and bacteria out * _Teat cistern_ - Duct in teat, 30-40mml of milk. Seperated from streak canal via rosette * _Gland cistern_ - seperated from teat cistern by cricoid folds. holds 400mml of milk * _Stroma_ - Contains fibroblasts, adipocytes, plasma cells & blood vessels * _Alveoli_ - **Secreting epith**elium. each surrounded by **myopithelium** & **capillaries. Groups of alveoli empty into d**ucts, forming functional unit **lobule**=\> lobe.

Answer 31

_Median Suspensory ligament_ - Seperates left and right udders. Elastic tissue allows distention for weight of milk _Lateral suspensory ligament_ - Inflexible and surrounds outer udder. Attached to prepubic and sub pubic tendons

Answer 32

One gallon of milk requires 400 gallons of blood! * _External pudic artery_ has 2 branches. **1 for each udder**. Arranged in a **sigmoid flexure** to avoid damage due to excessive weight * _Mammary artery_ branches into **cranial** and **caudal mammary artery** Blood exits via: 1. **_Subcutaneous abdominal vein_** - When standing. **empties** into **cranial vena cava** 2. **_External pudic vein_** - when sitting. **Empties** into **caudual vena cava**

Answer 33

* **Mammary ridge proliferates** into **mesenchyme** (dermis) * **Branches out**, furthur penetrating dermis * Each branch lengthens forming **duct systems. Myoepitelial cells** surround teminal portions * **Parathyroid hormone like protein** induces **BMP4** receptors. Binding causes **MSX2** expression. causing no hair growth.

Answer 34

_Lactogenesis_ * Ability to secrete milk * Lactating in late gestation = stage 1 * Lactation after birth = stage 2 _Galactopoiesis_ * The production of milk **dependant on removal of milk.** * When its not removed, capillary supply decreases. **Supply demand response**

Answer 35

* _Osterogen_ - **Inhibits milk secretion**. develops stromal tissue & **growth of extensive ductal system.** * _Progesterone_ - **Promotes** lobule/**alveoli** development. **Inhibits milk secretion** * _Prolactin_ - **Promotes milk synthesis**. **Dopamine** usually **inhibits prolactin**. Increase in prolactin causes **increase in oxytocin**. **suckling inhibits dopamine**. * Decreases in progesterone and oestrogen causes increased prolactin * **GH** works **synergistically** with **oestrogen** to **develop ducts.** * _Glucocorticoids_ - maintain tight junctions in breast parenchyma

Answer 36

Suckling causes neuronal messages to **paraventricular** & **supraoptic nuclei** of hypothalamus =\> **oxytocin release**=\> **Myoepithelial contraction**

Answer 37

Epithelial cells de-differentiate during dry period. Non secretions within 7 days

Answer 38

* **Oestrogens** stimulate **hypertrophy** of **myometrium**. Forms gap junctions allowing myometrium to act as a **syncitium** * _Brachystasis_ - When myometrium contracts and shortens doesnt regain normal length on relaxation. * Uterus divided into 2 sections. **Upper contractile portion** and **lower passive region**. **retraction ring** can be felt between segments * _Oxytocin_ - **Lowers excitation threshold** of muscle cells * _Prostaglandins_ - Stimulates **liberation** of **Ca+2** from intracellular stores

Answer 39

* _Cervical softening_ - **Increase in GAG's** =\> **increase** *_keratin sulphate_* (binds collagen **loosely**) & **decreased** *_dermatin sulphate_* (binds collagen **tightly**) * _Cervical ripening_ - **Increased vascularisation, influx of monocytes** and raised levels of **IL6** & **IL8** * _Cervical dilation involves_ - **Increased hydration, disorganization and viscoelastibility** Regulated by 1. _Prostaglandins_ - Induce **collagen breakdown**, alter GAG & proteoglycan composition 2. _Nitric oxide_ - Inhibition of INOS prevents ripening & **NO induces PG's release** 3. _Relaxin_ - Increases dramatically during 38-42 weeks. released from CL

Answer 40

**Oestrogen** induces **liberation of PLA₂** from lysosomal stores, whereas **P4 stabilises lysosomal** membranes. When **E2:P4 increases, prostaglandin production increases** Oestrogen also increases uterine oxytocin receptors

Answer 41

* Foetal pressure on cervix causes oxytocin release * Oxytocin lowers threshold in myometrium, causing contractions * This causes an increase in pressure on the cervix thus more oxytocin released * Positive feedback loop

Answer 42

* Goats * Cow * Dogs * Pig * Rabbit Foetal stress induces **ACTH release** =\> **Cortisol**. Cortisol induce **aromatase**, which increases the conversion of **DHA** into **oestrogen**. oestrogen induces prostaglandin (PGF2a) =\> luteolysis

Answer 43

* Sheep * Guinea pig * Cat * Horse Foetal stress induces cortisol release. Cortisol up regulates **17a** **hydroxylase**, **C17-20 lyase** & **aromatase**. These convert progesterone into oestrogen. Humans lack 17a hyroxylase and C17-20 lyase enzymes, therefore cortisol doesnt initiate parturition.

Answer 44

* Prostagen increase at the end of gestation * **Oestrogen decrease at parturition**. Instead fetus produces large amounts of **equilin** and **equilenin**, **BUT classical oestrogens required for labour initiation** * Cortisol increases 2-3 days before parturition * **Oxytocin** decreases through pregnancy, **increases at parturition** * Fetus produces large amounts of **P5**, **converted to P4** in placenta then **DHP** by **5a reductase**

Answer 45

* *_Cow_* - PGF2a * _Sow_ - PGF2a * _Sheep_ - **Corticosteroids** at 144 days induce lambing in 48 hours * _Dog & cat_ - **Low dose oxytocin** with **anti progestin** induces parturition