ANSC 431 Exam 4 Study Guide - Toxicology and Reproductive Biology

These flashcards cover key vocabulary and concepts related to toxicology and reproduction in various species, particularly focusing on endocrine disruptors, reproductive strategies in birds, sharks, and fish.

Endocrine Disrupting Chemicals (EDCs)

Substances causing adverse health effects by disturbing hormone production or activity.

Agonist

A substance that mimics hormones and activates their receptors.

Antagonist

A substance that binds to receptors but does not activate the signaling pathway.

Non-monotonic Dose Response Curve

A graph showing that effects do not consistently increase or decrease with dose.

Examples of EDCs

Includes dioxins, phthalates, PFAS, bisphenol, found in various products.

Exposure routes for EDCs

EDCs can enter the body through breathing, eating, drinking, or touching.

Cocktail effect

Substances in mixtures having different effects than individually.

Heavy metal contaminants

Toxic elements like mercury, lead, cadmium, and arsenic affecting health.

Mercury sources

Methyl mercury from seafood; ethyl mercury from vaccines.

Lead exposure

Inhalation of contaminated air; ingestion via lead pipes or paint.

Cadmium sources

Found in cigarette smoke and certain vegetables.

Arsenic contamination

Presence in contaminated water supplies.

Effects of heavy metals on males

Disruption of testis barrier and decreased testosterone due to oxidative stress.

Effects of heavy metals on females

Decreased levels of sex hormones like GnRH, FSH, LH, and reduced ovarian function.

Ovulatory cycle of hens

Follicle growth stimulated by FSH; ovulation triggered by an LH surge.

Estrogen role in hens

Stimulates albumen synthesis and yolk protein development in follicles.

Oviposition mechanics

Contraction of shell gland stimulated by posterior pituitary secretions.

Timing of egg laying in hens

Eggs are ovulated 6 hours after an LH surge and laid 26.5 hours later.

Estradiol's role in LH surge

Rising estradiol levels stimulate the LH surge necessary for ovulation.

Testicular regression in seasonal breeders

Occurs in non-breeding season leading to reduced reproductive function.

Testosterone effects in male birds

Regulates song, aggression, and sexual displays.

Sperm storage in female birds

Sperm can survive in utero-vaginal junction folds for 2-15 weeks.

Determinacy in egg laying

Fixed clutch size, unaffected by environmental changes.

Indeterminacy in egg laying

Variable clutch size, responsive to environmental cues.

Altricial young

Hatch helpless, featherless, and with closed eyes.

Precocial young

Hatch with open eyes and down feathers; can move shortly after hatching.

Components of the egg

Yolk, albumen, shell membranes, and shell serving protective functions.

Amnion

Membrane surrounding the embryo that secretes amniotic fluid.

Chorion

Protective membrane surrounding all embryonic structures.

Allantois

Membrane involved in respiration and excretion, growing larger with embryo.

GnRH in males

Increases in late fall to stimulate testis size for breeding.

Melatonin's role in reproduction

Regulates reproductive cycles based on daylength.

Thyroid hormones in reproduction

Increase TSH, T4, and T3 with increasing daylength, activating GnRH.

Photostimulation

Occurs with increased daylength, stimulating reproductive hormones.

Photorefractoriness

Inhibits reproductive system in response to long photoperiods.

Photosensitivity

Resets reproductive cycles during extended short photoperiods.

Prolactin in birds

Important for nesting and parental behavior.

Sharks' reproductive cycle

Stages include immature females; breeding frequency may vary.

Shark reproductive lifespan

Slow to mature, with gestation longer than 12 months.

Oviparity in sharks

Lay eggs in ocean; no care for eggs afterward.

Viviparity in sharks

Live birth with developing young nourished through placenta.

Ovoviviparity in sharks

Eggs hatch inside female's body with no placenta.

Neuroendocrine regulation in sharks

Involves GnRHI and GnRHII for reproductive cycles.

Fertilization methods

Oviparous, ovoviviparous, viviparous.

Fish reproductive strategies

Dioecism and hermaphroditism, influencing mating behavior.

Mating partnerships in fish

Monogamy, polygyny, polyandry, and polygynandry.

Types of fish spawning

Pelagic and benthic, affecting egg survival strategies.