Homeostasis Flashcards
definition of homeostasis
the existence of a stable internal environment. conditions that must controlled include body temperature, blood content, CO2, blood sugar, BP.
what is homeostatic regulation
homeostatic regulation is the adjustment of physiological systems to preserve homeostasis
elements of homeostatic control- 1,2,3
1- stimulus (produces change in variable)
2- receptor- detects change
3-input- information sent along afferent pathway to control centre
elements of homeostatic control- 4,5
4- output- information sent along efferent pathway to effector
5- response- of effector feeds back to reduce the effect of stimulus and returns variable to homeostatic level
negative feedback system
is the primary mechanism for homeostatic regulation, maintain a normal range rather than a fixed variable (small changes are ignored)
example of negative feedback system
temperature control, pH, blood sugar
positive feedback system
not as common. typically found where potentially dangerous or stressful process must be completed
example of positive feedback system
haemostasis, labour and delivery
systems integration- body overheats
sweating, dehydration, blood volume lost- heart works harder, kidneys respond to keep more water
homeostatic regulation mechanisms- intrinsic
auto-regulation- cells tissues, and organs adjust automatically to environmental changes
homeostatic regulation mechanisms- extrinsic regulation- nervous system
fast, short lasting, crisis managememnt
homeostatic regulation mechanisms- extrinsic regulation- endocrine system
longer to react, longer lasting
extrinsic regulaiton- autonomic nervous system
homeostasis is a dynamic balance between autonomic branches
Parasympathetic system- rest and digest, slows down things, sympathetic system- fight and flight system, accelerator, speeds things up
why are young people vulnerable to homeostatic disruption
venerable to significant alterations in homeostasis due to immaturity of the system- immune system, renal function, endocrine system, thermoregulation (first 6-9 months children cannot control temp)
components of homeostasis
norm altered- detected by receptors- control centre- effector response- norm restored
