PPP - homeostasis, body fluids, flow & pressure Flashcards
What is the purpose of short term homeostasis?
immediate survival
What is the purpose of long term homeostasis?
health and reproductive capability
What are some medium-term variables?
temperature, metabolic rate, appetite, GI secretions
What is an example of a long term variable?
steroid hormone levels
Give an example of hierarchy of importance for physiological variables?
Plasma osmolality will be maintained at the expense of blood volume by taking in more water - leading to hypertension
What is the purpose of negative feedback?
to move a variable back to a set point when it is altered?
When can the set point of a physiological variable be altered?
in fever or exercise
What are the 3 types of negative feedback?
neuronal, endocrine and local/chemical
Where are the integrating centres for negative feedback mechanisms?
in the midbrain and brainstem
Give examples of peptide hormones?
ACH, oxytocin
Example of a polypeptide hormone?
GH, insulin
Example of a glycoprotein hormone?
LH, FSH, TSH
Exampe of amino acid dervivative hormones?
adrenaline, T4
Example of steroid hormones?
progesterone, androgens, glucocorticoids
How do protein hormones work?
receptor binding on membrane induces 2nd messenger action
- effects are rapid and transient
How do steroid/thyroid hormones work?
intracellular receptor binding alters gene transcription
- effects are slow and prolonged
What is an example of local negative feedback?
local control of blood flow
control of blood volume
What is feedforward control
anticipation of a change brings about a response before the change is detected
What type of feedback is feedforward normally?
neuronal