Homeostasis Flashcards
Homeostasis is the process by which _______ is maintained inside an animal
an internal balance of materials and energy (or steady state)
Can Homeostasis be at a cellular level?
Yes
What is the overall result of Homeostasis?
Animal more independent of the environment
How is homeostasis maintained?
Regulation through positive or negative feedback (via chemical or electrical communications between tissues)
Conformity (conformer):
unable to maintain homeostasis for internal conditions (internal conditions vary with environment)
Regulation (Regulator):
use biochem, physical, behavioral mechanisms to regulate internal changes over range of environmental changes
Invertebrates are?
Vertebrates are?
Conformer
Regulator
Thermoregulation:
maintain body temp within tolerable range
Osmoregulation(acid-base homeostasis):
regulate solute balance and gain/loss of water
Excretion:
Removal of nitrogen containing waste products of metabolism such as urea
Types of regulation in animal body
Thermoregulation Regulation of hormone secretion Osmoregulation Excretion Oxygen Regulation
Examples of regulated variables
temp blood glucose concentration blood ph blood oxygen hormone
Blood Glucose regulation(for increase):
When glucose level increases _____ cells secrete _______ Awhich converts glucose to ______ so that extra glucose can be ______.
beta
insulin
glycogen
stored
Blood Glucose regulation (decrease):
When glucose level falls ____ cell’s secrete _____ which converts stored glycogen to _______. Bringing back to normal level
alpha
glucagon
glucose
Hypothalamus does what? and how?
monitors blood temperature flowing through it
by receiving info of external temp from thermoceptors
What are passive and active processes for core temp?
passive: when core temp changes slightly, regulates through control of heat conductance by varying blood flow or insulating fur/ feathers
active: for major changes of temp: thermogenesis or evaporative heat loss develops
Mechanisms of Thermoregulation
Behavioral
Structural/anatomical
physiological
thermogenesis
Mechanisms of thermoregulation change what factors?
surface area
temp gradient
thermal conductivity
radiation and convection
Behavioral Thermoregulation
Change posture, find better environment
ex: huddle, panting, go in water
Structural/anatomical thermoregulation
Insulation increase/decrease (fur, hair, feathers, blubber)
Philoerection:
hairs stand up when cold to trap more air and increase insulation
Vasodilation: expansion of diameter of ________ to elevate _______ in the skin and increase ________ to a cool environment
superficial blood vessels
blood flow
heat transfer
Vasoconstriction:
reduces ______ and _______ by decreasing diameter of ________.
blood flow
heat transfer
superficial vessels
Countercurrent heat exchange: special arrangement of _________ that help trap ______ in the body core and reduce _______
blood vessels
heat
heat loss
Physiological Thermoregulation
sweating, panting
torpor, dormancy (hibernation): reserve energy during environmental extremes ( no heat transfer)
How do small birds make it through winter in winnipeg?
Decrease thermal conductance by increasing fur thickness and dropping core temp
How seal, whale and polar bear survive cold water?
increase metabolic rate
increase skin insulation (more blubber under skin)
blood can bypass blubber
