homeostasis and the acid base/ balance Flashcards
what is homeostasis
Homeostasis is the process by which living organisms maintain a stable internal environment despite changes in external conditions.
inis essential for the survival an proper functioning of organisms
what are they key points of homeostasis
-balance and stability
-feedback mechanisms
-negative feedback
-positive feedback
-dynamic equilibrium
-used to keep boys internal environment in a state of balance.
what are feedback mechanisms and what do they typically involve
they are used to detect changes and respond accordingly.
they typical involve:
-sensors
-control centre
-effectors
what is negative feedback
This is the most common type of feedback mechanism. When a change is detected, negative feedback works to counteract the change and bring conditions back to their normal range.
e.g: if body temp rises, you sweat and increase blood flow to skin to cool your body down.
how does blood clotting work including positive feedback
Injury: When you get a cut or wound, blood vessels are damaged, and bleeding starts.
Platelet Activation: Platelets in the blood become activated and start to stick to the site of the injury.
Chemical Signals: These activated platelets release chemicals that attract even more platelets to the site.
More Platelets: The arrival of more platelets releases even more chemicals, attracting even more platelets.
Clot Formation: This cycle continues, rapidly increasing the number of platelets at the site, forming a blood clot that seals the wound.
This process amplifies the initial response (platelet activation) to quickly stop bleeding and promote healing.
does homeostasis involve keep everything equal or maintain variables within a range
maintaining variables within a range that supports life, sort is constant;y adjusting to change.
what is acid-base balance
the mechanisms of the body uses to maintain its blood an other bodily fluids within a narrow pH range that is crucial for normal cellular functions.
bloods normal pH level is between 7.35 and 7.45.
what are the key components to maintaining blood pH
-buffers: help keep pH stable by soaking up excess H+ ions hydroxide ions.
-respiratory system: controls pH by adjusting CO2 levels
-renal system: maintains pH balance by excreting H+ (lowers acidity) and reabsorbs HCO3 (neutralises acid)
what is acidosis
when blood becomes too acidic
what is alkalosis
when blood becomes to acidic
what happens to anaerobic metabolism, CO2 accumulation and combines acidosis during cardiac arrest
Anaerobic Metabolism: During cardiac arrest, reduced blood flow leads to a lack of oxygen. Cells switch to a less efficient process called anaerobic metabolism, which produces lactic acid and causes metabolic acidosis.
CO2 Accumulation: With ineffective breathing and circulation, CO₂ builds up in the blood. CO₂ mixes with water to form carbonic acid, leading to respiratory acidosis.
Combined Acidosis: Both types of acidosis (metabolic and respiratory) can occur together during cardiac arrest, significantly lowering blood pH and disrupting cell function.
what effect does acidosis have on the heart and resuscitation
Reduced Heart Function: Acidosis weakens the heart’s ability to contract effectively, making it harder for the heart to pump blood properly when circulation is restored.
Electrolyte Imbalance: Acidosis disrupts electrolyte levels, such as potassium and calcium, which are crucial for normal heart function. High potassium levels can lead to dangerous heart rhythms.
Defibrillation Effectiveness: Severe acidosis can make defibrillation less effective, reducing its ability to restore a normal heart rhythm during cardiac arrest.
summary of acidosis on cardiac arrest
The acid base balance is carefully regulated to optimise cellular metabolism
During cardiac arrest, the build-up of metabolites & CO2 may cause acidosis, which acts to reduce oxygen delivery to cells, reduce myocardial contractility, & cause myocardial irritability
This makes ROSC more difficult to achieve
The longer the ‘arrest’ the greater the acidosis
how can paramedics prevent acidosis
-ventilate at the correct respiratory rate
-ventilating to tidal volume
-CPR depth/rate/rhythm.
