Nerves Hormones and Target Tissue


Animal Reproduction - the regulation of nerves, hormones and target tissues
Alannah Kelly
Flashcards by Alannah Kelly, updated more than 1 year ago
Alannah Kelly
Created by Alannah Kelly almost 11 years ago

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Question Answer
Highlight the difference between a simple neural reflex and neuroendocrine reflex. Simple: employs nerves that release their neurotransmitters directly onto target tissue. Neuroendocrine: requires that a neurohormone enters the blood and acts on the remote target tissue.
What Hormones does the hypothalamic nuclei produce? GnRH and Oxytocin.
How does the paraventricular nucleus and surge/tonic centres communicate with the posterior and anterior pituitary respectively? anterior: a special circulatory modification called the hypothalamo-hypophyseal portal system. posterior: neurons are deposited directly into capillaries in the posterior pituitary.
Classify reproductive hormones by their glandular origin. Hypothalamus Pituitary Gonads Uterus Placenta
What hormones does the hypothalamus produce? GnRH Gonadotropin releasing hormone
What hormones does the pituitary produce? FSH: follicle stimulating hormone LH: luteinizing hormone Oxytocin
What hormones do the gonads produce? In the ovary: estrogens, progesterones, inhibin, some testosterone, oxytocin and relaxin. In the testes: testosterone and other androgens, inhibin and some estrogens.
What hormones are produces in the uterus and placenta? Uterus: prostaglandin F (PGF) Placenta: progesterone, estrogen, equine chorionic gonadotrophin (eCG) and human chorionic gonadotrophin (hCG)
Classify reproductive hormones by their mode of action. Neurohormones Releasing hormones Gonadotrophins Sexual Promoters Maintenance of Pregnancy Luteolytic
Classify reproductive hormones by their biochemical structure. Proteins Inhibin and activin steroids prostaglandins
The strength of hormone action is influenced by: The pattern and duration of secretion. The half-life of the hormone. The density of the receptors on the target organ. Receptor-Hormone affinity.
Define Agonists: Analogs (having similar chemical structures) that bind to receptors and initially cause the same biological effect as the hormone. Some artificial hormones are more efficient than the native hormones.
Define Antagonists greater affinity for the hormone receptor but promote weaker biological activity by blocking receptors.
How are steroid and protein reproductive hormones metabolised by the liver and excreted in the urine and faeces? 1. Steroid secreted by gonads. 2. Steroid enters blood and goes to target tissue. 3. Steroid causes change in target tissue. 4. Steroid in blood passes through the liver. 5. Liver renders steroid H2O soluble. 6. Reenters blood and kidney or enters bile. 7. Excreted in urine and/or faeces as glucuronide or sulfate.
What are the practical implications of being able to measure hormones in urine, faeces and saliva? -non invasive but you are measuring hormone metabolites not the biological active hormone. - a lot of work and theres a lag phase.
What are the typical patterns of hormonal secretion by the reproductive system and give an example of each? Episodic: usually hormones under direct nervous control (GnRH, LH and T) Basal or tonic: low but fluctuates with low amplitude pulses (FSH) Sustained: hormone remains elevated but secreted in a stable stead state (Progesterone)
Define Up-regulation: Receptor density is elevated.
Define Down-Regulation: Reduced receptor density.
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