Intro to Physiology Flashcards
What is animal physiology?
the study of how animals work, focuses on function of tissues, organs and organ systems. relies on understanding of structure and function
explain levels of organization
a framework to describe scale in the organism. Different levels include organs to tissues to cells
Systems involved in regulating body temp
integumentary
muscular
cardiovascular
nervous
systems involved in body fluid composition
digestive
cardiovascular
urinary
skeletal
respiratory
lymphatic
systems involved in body fluid volume
urinary
digestive
integumentary
cardiovascular
lymphatic
systems involved in waste concentration
urinary
digestive
cardiovascular
systems involved in blood pressure
cardiovascular
nervous
endocrine
define homeostasis
the integrative actions of the systems of an organism that results in maintenance of optimal internal environment despite variations and fluctuations in external conditions
how is homeostasis controlled?
feedback loops or reflex control pathways
what are the two major homeostatic control systems of many animals?
nervous and endocrine
requirements for homeostasis, and briefly describe them
a receptor - senses any change in conditions
a control centre - receives and processes information and initiates response
effector - carries out response dictated by control centre.
negative feedback
opposes the original stimulus
positive feedback
enhances stimulus
rarer than negative
where is adherence to set point determined?
in the integration centre. the sensor just reports information, the integration centre is what knows if the information is good or bad
negative feedback loops, explain what they are and their end goal
negative feedback is the primary mechanism of homeostatic regulation. Provides long term control over internal conditions and systems
end goal: restore homeostatic normal range
what are the receptors, control centre and effectors for body temperature regulation for overheating/coldness
receptor: temperature sensors in body
control centre: the brain (hypothalamus)
effector:
too hot- blood vessels and sweat glands in skin (increase blood flow to skin to release heat, increased sweating)
too cold- shivering, reduced blood flow to skin, decreased sweating
why are positive feedback loops so rare?
stimuli rarely need to be enhanced. they are only used in dangerous or stressful situations, when homeostasis needs to be controlled quickly.
example of positive feedback loop
Severe cut
consequences: lower blood pressure and reduce cardiac efficiency. Dangerous! Calls for positive feedback mechanism
The loop: damaged cells release chemicals triggering blood clotting. these chemicals trigger chain reactions, a clot is formed, and each component added to the clot releases more chemicals that recruits more cells, proteins, etc. to further clot. this escalation is a positive feedback loop.
regulators
maintain relatively constant internal conditions despite external conditions. can counter environmental changes to an extent (dont know when this limit is)
conformers
allow internal conditions to change when faced with variation in environment. much less metabolically costly. system parameters paralleled the environment.
