Homeostasis Flashcards
Define homeostasis
It is the ability of a system or living organism to adjust it’s internal environment to mantain a stable equilibrium
What is the purpose of homeostasis?
To provide an optimal fluid environment for cellular function
What is meant by extrinsic homeostatic control?
The control system is outside the tissue being controlled (e.g. brain controlling the homestaiss of a different organ tissue)
What is meant by intrinsic homeostatic control?
The regulation occurs from within the system being regulated (autoregullation)
What is meant by intracellular homeostatic control?
The regulation of homeostais in a cell by the cell itself
What can occur if homeostasis is not maintaned?
If homeostasis is not mainted and conditions within the cell fall outside their normal ranges, it can lead to protein denaturation, which is a threat to the life of the cell
What does damage in blood vessels from high glucose levels can lead to? (name 3)
Artherosclerosis, kidney disease, retinopathy
What is the normal ICF Na+ concentration?
15mM
Where is Na+ concentration high and K+ concentration low?
ECF
What is the normal interstitial fluid Na+ concentration?
145mM
What is the normal plasma a+ concentration?
142 mM
Reference value of arterial pH
7.35 to 7.45
Reference value of Glucose
75 -110mg/ 100ml – 4.4 -5.0mmol/L
Reference value of Na+
135 - 145 mEq/L
Reference value of Bicarbonate
24 - 28 mEq/L
Reference value of K+ serum
3.5 - 5.5 mEq/L
WHat are the steps of the feedback loop?
Stimulus –> Receptor –> Coordinator –> Effector –> Response
What is the name of the receptor that monitors pressure?
Barorecpetors
What do chemorecpetors monitor?
CHemical substances: e.g.oxygen, carbon dioxide, pH in carotid arteries, etc
What receptors monitor osmosis?
Osmoreceptors
What receptors monitor temperature?
Thermoreceptors
Which is more common in the body: negative feedback or positive feedback?
Negative feedback
Give one example of positive feedback
Lactation (secretion of milk)
Give two examples of negative feedback
Temperature regulation and Glucose regulation
What is meant by “anticipation”?
It is a predictive response. The reponse is activated before any changes, the body predicts those changes will occur
What are 4 types of adaptation responses?
Genetic adaptation (inherited reponse), Accomodation, Acclimation, Acclimatisation (all three are acquired reponses)
What is accomodation?
Immediate physiological change in sensitivity of cells to changes in extrenal environment
What is acclimation?
Long term physiological changes in response to exposure to artificial or simulated changes in environment
What is acclimatisation?
Long term physiological changes in response to exposure to natural changes in environment
What are two benefits of having a fever?
The high temperature kiils pathogens and enhances phagocytosis
List the steps of what happens during an infection that lead a fever to develop
bacteria enters the body –> causes bone marrow to produce more macrophages –> macrophages secrete endogenous pyrogens (educados piratas) –> secreted into the bloodstream –> cause the hypothalamic set point (the temp at which the hypothalamus regulates the body temp) to increase –> feedback mechanisms loops start in the body –> body temperature increases –> temperature rises above normal –> fever
Older adults may sometimes not show fevers, what are 4 symptoms they may show of an infection?
Feeling hot/cold, vivid dreams, hallucinations and hedaches
True or false: Children showcase higher temperatures than adults for relatively minor infections
True
What is a reason some people feel comfortable in temperatures that are too cold for those around them?
Their temperature set point might be naturally lower
What is an effector?
Any organ or tissue that receives information from the integrating centre and acts to bring about the changes needed for homestasis to be maintained
Name two diseases that result from homestatic imbalance
Diabetes and heart failure
True or false: Aging is a source of homeostatic imbalance as the control mechanisms of the feedback loops lose their efficiency, which can cause heart failure
True
What region of the brain controls temperature, heart rate, blood pressure, satiety and circadian rythms?
Hypothalamus
What is meant by sensitivity in homeostasis, give one example.
More than one stimulus can sensitize the loop. Low Po2 and high PCO2 both trigger increased ventilation however the response when both occur together is greater than the sum of when they occur independently
All homeostatic control mechanisms have at leats how many interdependent components for the variable being regulated?
At least three
