What do you mean by physiological buffers? What are the different types of buffers found in the blood? If possible, please state examples.

Answer 1

Physiological buffers are chemicals used by the body to prevent large changes in the #"pH"# of a bodily fluid.

The four physiological buffers are the bicarbonate, phosphate, hemoglobin, and protein systems.

The #"pH"# of a buffer is determined by the Henderson-Hasselbalch equation:
#"pH" = "p"K_a + log(["A"^-]/["HA"])#
The buffer is best able to resist changes in #"pH"# when the #"pH"# of the buffer is close to the #"pH"# of blood (7.37 to 7.42), so the #"p"K_a# of the acid should be close to 7.4.

Phosphate Diversion

The phosphate buffer system consists of #"H"_2"PO"_4^(-)# and #"HPO"_4^(2-)# ions.

The balance is

#"H"_2"PO"_4^(-)("aq") + "H"_2"O" ⇌ "H"_3"O"^+("aq") + "HPO"_4^(2-)("aq")#; #"p"K_a = 7.21#
The phosphate buffer can easily maintain a #"pH"# of 7.4.

Carbonate Suppressant

The balance is

#"H"_2"CO"_3("aq") + "H"_2"O(l)" ⇌ "HCO"_3^(-)("aq") + "H"_3"O"^+(aq)#; #"p"K_a = 6.1#
This buffer functions in exactly the same way as the phosphate buffer, but it is not ideal because its #"p"K_a# is too far from #"pH"# 7.4.
Perhaps more importantly, the enzyme carbonic anhydrase converts #"H"_2"CO"_3# into #"CO"_2# that is dissolved in the blood and is then exhaled as #"CO"_2 #gas.

Blood globin

The overall formula is:

#"HHb"^+ + "O"_2 + "H"_2"O" ⇌ "HbO"_2 + "H"_3"O"^+#; #"p"Ka = 6.8#
It shows that oxygenation of #"Hb"# promotes the formation of #"H"_3"O"^+#.
This shifts the bicarbonate buffer equilibrium towards #"CO"_2# formation, and #"CO"_2# is released from the red blood cells.

Proteins

A protein is a long chain of amino acid residues, but this long chain still has free carboxylate groups #"COO"^(-)# and free amino groups #"NH"_2#.

The formula for a protein buffer system could be expressed as

#"H"_3stackrel(+)("N")—"R—COO"^(-) + "H"_2"O" ⇌ "H"_2"N—R—COO"^(-) + "H"_3"O"^+#

After that, the protein can serve as a buffer.

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Answer 2

Physiological buffers are systems within the body that help maintain the pH balance of bodily fluids by regulating the concentration of hydrogen ions. The main types of buffers found in the blood are bicarbonate buffer system, phosphate buffer system, and protein buffer system. Examples include bicarbonate ions, phosphates, and plasma proteins like albumin and hemoglobin.

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

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