Homeostasis

Homeostasis

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Maintaining and regulating Internal balance 

Maintenance of a state of dynamic equilibrium and homeostasis control systems use the principle of negative feedback to maintain systems within narrow limits 

Dynamic = something that changes all the time 

Equilibrium = the same/equal

Negative feedback restores the system to within the narrow limits, these levels are detected by the sensory receptors. The information is then relayed to the coordination centre. 

Nervous system vs endocrine system 

Nervous system

Endocrine system

Detect our surroundings and respond to stimuli and coordinate our behaviour. Message carried in nerves to specific location eg: muscle 

Made of endocrine glands which secrete hormones directly into the blood and produce an effect on target organs

Uses electrical impulses to communicate 

Uses chemical messages(hormones)to communicate 

Fast acting 

Generally slow acting

ENZYMES

pH in blood = 7.35 - 7.45

Optimum temp and pH is important because:

Increase in CO2 results in an accumulation of H+ ions in the cytoplasm of red blood cells - haemoglobin

Catalyse the addition of  phosphate ion to ADP when protons flow from the intermembrane space to the mitochondrial matrix  - ATP synthase

Catalyse the reactions that form phosphodiester bonds between DNA nucleotides in the synthesis of the leading strand - DNA polymerase 

Glucose concentration:

Too much - liver stores the excess glucose but if it stays to high could end up with hyperglycemia 

damage to vessel, loss of  limb

peripheral nerve damage, damage to eyes(pressure)

Weight loss, frequent urination 

Too little - shakiness, irregular heartbeat,

cells starved for energy 

Water potential & osmosis

• Pure water has the highest possible water potential (0kPa)

• When solute is added…