Chapter 3 - Terrestrial Environment Flashcards
How do temperature, humidity, and concentrations of gases and particulate matter differ between the micro- and macroenvironment? Light?
Often higher in microenvironment, while light is lower.
How SHOULD animals be housed?
SHOULD be housed within temp and humidity ranges appropriate for species, to which they can adapt with minimal stress and physiologic alteration.
What is the thermoneutral zone? What is it bound by?
TNZ - ambient temperature range in which thermoregulation occurs without the need to increase metabolic heat production or activate evaporative heat loss mechanisms. Bounded by lower and upper critical temperatures.
What is the TNZ of mice, rats, gerbils, rabbits, and dogs/cats?
Mice: 26-34C
Rats: 26-30C
Gerbils: 28-32C
Rabbits: 15-20C
Cats/Dogs: 20-25C
Where SHOULD dry-bulb temperatures be set in animal housing rooms? Why? What SHOULD be provided?
Should be set below the animals’ lower critical temperature to avoid heat stress. Should provide adequate resources for thermoregulation.
How does the LCT of newborns compare to adults?
LCT is higher in neonates.
Where should temperatures be maintained in reference to the ranges provided in the Guide?
In the middle of the ranges with minimal fluctuation.
What animals generally require a thermal gradient in their primary enclosures to meet basic physiological processes?
Poikilotherms and young birds
Abnormally high and low humidity is associated with what in mice? In rats?
Increased preweaning mortality in mice, ringtail in rats.
Elevated microenvironmental relative humidity in rodent isolators may impact what other cage parameter?
Can lead to high intracage ammonia concentrations
What physical structures impact how the microenvironments are ventilated and SHOULD be considered?
Type and location of supply air diffusers and exhaust registers in regards to primary enclosures.
What SHOULD be avoided in regards to air speed? This is particularly important for what animals?
Direct exposure to air moving at high velocity (drafts). Problematic for neonatal homeotherms, mutants lacking fur, and semiaquatic amphibians that can dessicate.
Modern HVAC systems allow ventilation rates to be set in accordance with heat load and other variables, but SHOULD always provide what?
Should always provide a minimum amount of air exchange, as recommended for general use laboratories.
If IVCs ventilate cages, why SHOULD the macroenvironment be ventilated? (4)
To address heat load, particulates, odors, and waste gases from primary enclosures
How is air exhausted from microenvironments handled?
If adequate filtration to address contamination risk, can be exhausted to animal housing room. Generally preferable to exhaust directly into building’s exhaust to reduce heat load and macroenvironmental contamination.
What is an advantage of recycled air? A risk? How SHOULD exhausted air be recycled? What SHOULD also be considered?
Saves energy but risks cross contamination. Should be filtered at minimum with 85-95% ASHRAE efficient filters to remove airborne particles. Also consider filtering volatile substances (ammonia).
What SHOULD be addressed in areas that require filtration to ensure personnel and/or animal safety?
Filter integrity, efficiency, and loading.
What HVAC parameters SHOULD be monitored?
Supply and exhaust air volumes, fluctuations in temp and relative humidity, and air pressure differentials between spaces
What are three potential photostressors?
Inappropriate photoperiod, photointensity, and spectral quality of light.
Intrinsically photosensitive retinal ganglion cells are important for what types of regulation? (3)
Neuroendocrine, circadian, and neurobehavioral
In general, what SHOULD light provided to an animal holding room provide?
Should be diffused throughout an animal holding area and permit sufficient illumination for animal well-being while permitting good housekeeping practices, adequate animal inspection including for the bottom-most cage, and safe working conditions. SHOULD provide for adequate vision and neuroendocrine regulation of diurnal and circadian cycles.
Photoperiod is a critical regulator of what?
Reproductive behavior
Will chickens eat in the dark? Why is this important?
Will not eat in low light or darkness, so illumination cycles SHOULD be limited to a duration that will not compromise their well-being.
What SHOULD be used to control the light cycle? How SHOULD this be maintained?
Should use a time-controlled lighting cycle to ensure a regular diurnal cycle, which should be checked regularly to ensure proper cycling.
