Some adverse outcomes of toxicity can include (3):
1) Growth
2) Reproduction
3) Survival
Many compounds introduced into the environment by human activity are capable of disrupting the ____________________ of animals, including fish, wildlife, and humans. The consequences of such disruption can be profound
endocrine system
Exogenous substance or mixture that alter function(s) or the endocrine system and consequently cause adverse health effects in an intact organism, or its progeny, or subpopulations:
Endocrine disrupting chemicals
Name 2 things that EDCs can do:
1) EDCs can mimic natural hormones by binding to their receptors
2) EDCs can alter recognition, biosynthesis, storage, release, transport, and clearance of hormones
Name a few things that EDCs can do:
- Decline in sperm quality
- Impair fertility
- Increase spontaneous abortions
- Imposex in mollusks
- Declining sex ratios (less men)
- Endometriosis (uterine tissue)
- Precocious / early puberty
- Neurobehavioural disorders
- Many cancers (?)
- Population declines in wildlife
Review of endocrinology (1):
- the endocrine system is a collection of ____________ glands
- glands in humans include: _________________________________
- glands synthesize and secrete __________
- ductless
- hypothalamus, pituitary, thyroid, parathyroid. adrenals, pineal body, pancreas, ovaries, and testicles
- hormones
T or F: Hormones are body’s messengers: transfer information and instructions form one set of cells to another
T
What is the main function of the endocrine system and hormones:
Maintain homeostasis and long-term control by means of chemical signals
T or F: The endocrine system works in parallel with the nervous system
T
Why are we concerned about EDCs?
- Because they are bioavailable and bioaccumulate
- Small changes are amplified (signal transduction)
- Effects cause by less than ppb concentration (relevant)
- Multiple effects and toxicities
- Inter-generational effects
- Mixtures = synergies
EE2 additions in lakes of UK caused:
- High vitellogenin production in males
- Delayed sperm cells
- Population impacts / less males
What is vitellogenin:
protein created in the liver that is transported to the ovaries to nourish the egg
General Adaptation Syndrome was supported by:
Hans Selye
General Adaptation Syndrome develops in _________ stages
three
T or F: The body’s resistance to stress can only last so long before exhaustion sets in
T
What are the 3 phases of stress:
1) Phase 1 alarm reaction (mobilize resources)
2) Phase 2 resistance (cope with stressor)
3) Phase 3 exhaustion (reserves are depleted)
Hypothalamus (releasing factor) - Anterior pituitary - ACTH (through blood) - _________________
Adrenal cortex releases cortisol
Fish in polluted environments and their cortisol levels: (study) what was the conclusion
The results suggested that a life-long exposure to chemical pollutants may lead to an exhaustion of the cortisol-producing endocrine system, possibly as a result of prolonged hyperactivity of the system
What are some challenges associated with evaluating behavioral ecotoxicology?
- latency period
- inter species sensitivity
- not easy to monitor in nature / how do you ask a fish how they feel
- tolerance / resistance / adaptation
What are some common measures of behavioral ecotoxicology?
- Avoidance: change in response to stimulus (light, temperature, salinity)
- Activity level: fatigue and lethargy / hyperactivity
- Feeding: cessation or diminished
- Performance: swimming speed, orientation
- Predation: reduced ability to avoid predators; sub-optimal predator foraging or prey-switching
- Reproductive behavior: endocrine disruption, reduced fecundity
- Social interactions: grooming, nursing , preening, singing
