Homeostasis Flashcards
What is homeostasis?
A condition of equilibrium (stability or balance) in the body’s internal environment
It is dynamic
Constant fluctuations of both the internal and external environment
Internal conditions usually vary within a very narrow range (pH blood 7.35-7.45)
Core body Temp
BP/HR/RR
BGL
What are the components of the feedback system?
Stimulus:
Any disruption to a controlled condition
Receptor/sensor:
Monitors the environment and responds to a stimulus
Control centre:
Determines set-point/range to be maintained. Analyses input and determines appropriate response (output).
Effector:
Muscles or glands which bring about a response or effect.
What is the negative feedback system?
Inhibitory, therefore negates a change
Prevent sudden severe changes within the body; reverses or negates original stimulus
Once equilibrium is achieved the response is reduced and the process “shut off”
More common
What is the positive feedback system?
Do not help to maintain equilibrium
Do not oppose a change in internal environment
Enhance and amplifies the effector so the response continues at a faster rate
Only stops when stimulus removed
Less common
What is disease (linked to homeostasis)?
What Is Disease?
Disease is any failure of normal physiological function that leads to negative symptoms.
While disease is often a result of infection or injury, most diseases involve the disruption of normal homeostasis.
Any disease process can lead to an imbalance of HOMEOSTASIS this imbalance is what we see in signs and symptoms.
What is necessary for homeostasis?
Effective receptors
Effective brain function–. control centre
Effective major organs
Skin / Musculoskeletal/ Lungs/ Heart/ kidneys/ Liver/Pancreas
An adequate blood volume
More cardiac specific
Effective blood vessels
An effective cardiac pump
Effective kidney function
What are the types of receptors?
Baroreceptors- pressure
Chemoreceptors-gases/chemical substances
Mechanoreceptors- stretch
Nociceptors- pain
Photoreceptors-light
Thermoreceptors- temperature
Homeostasis sign and symptoms?
The signs and symptoms we see are the result of the body’s way of maintaining HOMEOSTASIS
Therefore normal vital signs=normal homeostasis
Abnormal vital signs=a change in homeostasis, due to an acute situation or chronic disease process
What sign and symptoms will be present in DKA?
Hyperglycaemia
Severe fatigue
Polyuria
Polydipsia
Ketones in urine/pear breath
Increase RR
Acid base balance
pH of blood normal range for homeostasis is :
7.35-7.45 -> slightly alkaline
Discuss chronically high CO2 -> COPD patient may have a ‘normal’ mild respiratory acidosis…..
They have a chronic lung disease that is irreversible/ progressive and incurable
