homestasis

what do cells require?

a constant environment (INTERNAL ENVIRONMENT)

what is EXTRACELLULAR FLUID?

the internal environment within which cells exist

what is the internal environment affected by?

the external environment

what happens if a stable environment is not maintained?

disruption to internal environment

affects cellular function

what is the process by which the internal environment is maintained?

homeostasis

when does the state of homeostasis exist?

when all cell’s needs are met & functioning smoothly

what is essential between systems within the body in order to maintain homeostasis?

communication

what are the two regulatory systems involved in homeostasis?

nervous system

endocrine system

what does the endocrine system utilise?

hormones to regulate bodily functions

what does the nervous system regulate?

bodily activities via nerves & nerve impulses from regulatory centers within the CNS

role of the controlling centre

determine set point or range at which the variable being monitored is to be maintained

role of receptors

sensors of differing types which react to a stimulus

where do receptors send info

to the controlling centre following afferent pathways, or input

role of effectors

provide means by which the controlling centre effects the changes required to maintain the functions being controlled within the set point or range

what sort of pathway does info to effectors follow?

efferent pathway or output

what is the effect of these components relayed to the control centre referred as?

feedback

what is positive feedback referred to as?

stimulatory-stimulatory system

what is negative feedback referred to as?

stimulatory-inhibitory system

what does the positive feedback system do in response to the controlling system?

initiate a response which increases the variable to further deviate from the set point or range

examples of positive feedback

uterine contractions during childbirth

eating

blood clotting

what does negative feedback do in response?

brings the response variable back to the set point or range

examples of negative feedback

body temperature

blood pressure

blood glucose

what is the breakdown in homeostatic mechanism in older ppl seen as?

organs become less efficient leading to ill health