Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Animal Phys - L2
| Question | Answer |
|---|---|
| Placentation | formation of the placenta after embryo attachment to the uterus |
| The placenta | a transient maternal-foetal organs that supports the embryo during gestation |
| where does fertilisation occur? | fallopian tube |
| where does implantation occur? | the uterus |
| placenta classification is determined by: | type of attachment to uterine wall degree of invasiveness or number of maternal tissue layers retained |
| ruminant placenta type | cotyledonary, epitheliochorial |
| ruminant placenta structure | foetal side: cotyledon maternal side: caruncle together form placentomes |
| Placentomes | points of attachment |
| pig placenta type | diffuse, epithiliochorial many small attachment sites spread across uterine surface |
| how many uterine horns do sows have? | 2, to support large litters |
| Human/rodent placenta | hemochorial foetal chorionic tissue projects directly into maternal blood pools |
| Hormonal regulation of placental growth | placenta acts as temporary endocrine organ not under direct control of the brain (autonomous hormone secretion) maintains pregnancy by secreting oestrogen and progesterone |
| where does the follicle form after ovulation? | Corpus luteum (CL) |
| what hormones does CL secrete? | oestrogen and progesterone |
| CL without pregnancy | CL degrades, hormones fall and cycle restarts |
| CL with pregnancy | placenta releases chorionic gonadotrophin maintains the CL sustains release of progesterone and oestrogen |
| Functions of oestrogen and progesterone | maintain uterine environment for foetal development reduced motility retains endometrial tissue uterine enlargement |
| maternal physiological changes | increased blood volume increased respiration activity increased urinary output placental lactogen helps redirect nutrients to foetus |
| Chorionic Gonadotropin (CG) | maintains CL of pregnancy; stimulates foetal testes (XY) testosterone |
| Oestrogen | stimulates uterine muscle (myometrium) growth; prepares mammary glands |
| Progesterone | Inhibits uterine contractions; promotes cervical mucus plug; prepares mammary glands |
| Chorionic Somatomammotropin (placental lactogen) | supports mammary gland development; reduces maternal glucose use, increases mat metabolism for foetal energy |
| Relaxin | softens cervix and loosens pelvic ligaments for birth |
| Placental PTHrp | Increases maternal Ca++ for foetal bone mineralisation |
| Peptide hormone transport | water-soluble, circulate freely |
| Amine derivatives | catecholamines and thyroid hormones |
| catecholamines | 50% bound to plasma proteins |
| thyroid hormones | lipid-soluble, mostly bound |
| steroid hormones | lipid-soluble, 99% bound; only free fraction active |
| IGF-2 role and function | expressed in foetal and placental tissues structurally similar to IGF-1 but not GH dependent major stimulator of foetal and placental growth acts through paracrine and endocrine mechanisms |
| where is IGF-1 mainly expressed? | liver (postnatal) |
| Where is IGF-2 mainly expressed? | placenta, muscle, chorion (foetal) |
| IGF-1 developmental role | postnatal growth |
| IGF-2 developmental role | foetal and placental growth |
| IGF-1 expression trend | low in gestation, increases postnatal |
| IGF-2 expression trend | high in gestation, declines postnatal |
| Genomic imprinting | gene expression depends on parent of origin rather than both alleles equally certain genes are silenced on one parental allele via epigenetic regulation |
| IGF-2 inheritance pattern | expressed from paternal allele |
| IGF-2R inheritance pattern | expressed from maternal allele |
| Epigenetic control | cells inherit both genes and instructions on how to express them |
| what does expression depend on? | developmental stage, tissue, and parent of origin |
| DNA methylation | occurs at CpG islands in gene promoters includes hypermethylation and hypomethylation |
| Hypermethylation | silences gene |
| Hypomethylation | activates gene |
| Callipyge gene | sheep expressed only when paternal allele mutates |
| Histones and Chromatin | DNA wrapped around histones forming nucleosomes, packed into chromatin chromatin compaction silences unnecessary genes important for turning off developmental genes after use |
Created by:
sakelleher29
Popular Agriculture sets