buffer system

Buffer Syste

ms

By

Team B.N.Y.S

S-VYASA

And there

relatio

n with

nutritio

n

Contents…... INTRODUCTION ACIDS & BASES TYPES OF ACIDS & BASES pH BUFFERS TYPES OF BUFFER (MECHANISM) DISORDERS ROLE OF NUTRITION

Introduction

Acid-base regulation

–Regulation of hydrogen ion

• Buffer system

• Respiratory regulation

• Renal regulation

Why To Regulate

To maintain homeostasis

Regulates enzymatic functions

Acids And Bases

Acids

–Release protons (H) ;Eg-H2CO3 , HCL

Bases

–Accept protons (H) ; Eg-HCO3

Types of acids and bases Strong acids

–Release large amount of Hydrogen ions Weak acids

–Release small amount of Hydrogen ions Strong bases

–Accept large amount of Hydrogen ions Weak bases

–Accept small amount of Hydrogen ions

pH Hydrogen ion conc. Determines pH

What Is Buffer ??? A buffer is a solution (or a substance) that has

the ability to maintain pH and bring it back to

its optimal value by addition or removal of

hydrogen ions

Buffer + H H buffer

Contd…. When Hydrogen ion conc. Increases

–Reaction shifts towards right When Hydrogen ion conc. Decreases

–Reaction shifts towards left

In this way hydrogen ion concentration is maintained

Types of chemical buffer

–Carbonic acid-bicarbonate –

–Buffering changes caused by organic and fixed

acids

–Protein buffer system-Amino acids

–Minor buffering system-

–Phosphate –Buffer pH in the ICF

Buffer Systems in Body Fluids

Figure 27.7

Carbonic acid-bicarbonate buffer system

Weak acid – H2CO3

Bicarbonate salt (NaHCO3)

Strong acid is added

–When HCL is added Hydrogen conc.

increases

– CO2 + H2O H2CO3 H + HCO3

Carbonic Acid-Bicarbonate Buffering

System

Contd…

Strong base is addedH+ conc. Reduces

NaOH + H2CO3 NaHCO3+H2O

In this way CO2 conc. decreases

This inhibits respiration.

Carbonic Acid-Bicarbonate Buffer System

Bicarbonate buffer- Has the following limitations:

–Cannot protect the ECF from pH changes due to increased or depressed CO2 levels

–Only functions when respiratory system and control centers are working normally

– It is limited by availability of bicarbonate

ions (bicarbonate reserve).

Phosphate buffer system-

Main elements of phosphate buffer system-

- H2PO4, and HPO4

Phosphoric acid changes pretty quickly into

dihydrogen phosphate, or H2PO4-.  

This dihydrogen phosphate is an efficient buffer.

Contd…

Contd…. Phosphate buffer system in the ECF is low

compared to the bicarbonate buffer.

Its buffering power is less compared to the

bicarbonate buffer.

It has its importance in the renal

tubules of kidneys for two reasons.

.

Contd

1.Conc. of phosphate is more in tubules.

2. Tubular fluid has lower pH.

Conc. of phosphate is more in ICF compared

to ECF.

Proteins are made up of amino acids Amino acids have a central carbon with four

groups off of it:

1.a carboxyl group (COOH)

2.an amino group (NH2)

3.a hydrogen atom

4.an R group

.  

Protein buffer system

Structure of amino acids

Contd… The carboxyl and amino groups are what enable

proteins to act as buffers.

Carboxyl group is attached to the amino acid central carbon:   C - COOH

Carboxyl group consists of a double bond

to one of the oxygens and a single bond to the

hydroxyl group. 

Contd...

At neutral pH the carboxyl ion is present as COO instead of COOH.

Acidic medium – becomes COOH

Basic medium – becomes COO.

Contd…

Amino group is attached to the amino acid central carbon:  C - NH2.

Neutral pH, the amino group is actually- NH3

+ rather than just NH2.

Acidic medium – becomes NH3+

Basic medium- becomes NH2

Contd..

Respiratory regulation

When alveolar ventilation increases

CO2 conc. In ECF decreases

H+ conc. decreases

Or vice versa.......

Respiratory regulation Contd…

Pulmonary expiration of CO2 balances metabolic formation of CO2

–1.2 mol/L of dissolved CO2 is present in the ECF corresponding to pCO2 of 40 mm/hg

–Rate of pulmonary ventilation is inversely proportional to CO2 & pCO2

–So either pulmonary ventilation rate of CO2

– or its formation by tissues can change pCO2

in ECF.

Contd…

Increasing alveolar ventilation decreases ECF

hydrogen ion conc. And raises pH

– If alveolar ventilation increases the pCO2 decreases.

– If alveolar ventilation decreases the

pCO2 increases.

–Twice rise of AV--rises pH of ECF by about 0.23

–Decrease of AV to ¼ -- decreases pH by 0.45

Contd…

Increased Hydrogen ion conc. Stimulates alveolar ventilation

Change in alveolar ventilation rate is much greater in reduced levels of pH than in increased levels of pH

Reason

Alveolar ventilation rate decreases

Increases pH

O2 added in blood reduces

Demand of O2 in blood increases

pO2 also decreases

Stimulates ventilation

Feedback control of Hydrogen ion conc. By

RSH conc. Falls below normal

Respiration is depressed

Alveolar ventilation decreases

H increases back to normal

Bufffering power of RS

The kidneys work in elimination of hydrogen ion conc. and control imbalance.

Its capacity is 1-2 times as much as other chemical buffers.

Impairment of lungs function:

Impairment of lung function leads to

emphysema and respiratory disorders.

Kidneys play a major physiologic mechanism

for returning pH to normal

Renal mechanism of acid-base regulation

Kidneys regulate the blood pH by

1. maintaining alkali reserves

2. excreting / reabsorbing acid/base.

Urine pH is lower than blood pH

Kidneys- Acidification of urine.

Contd…

Excretion of hydrogen ions

Reabsorption of bicarbonate ion

Excretion of ammonium ions

What if th

ese buffer

syste

ms do not f

unction

properly…..?

??????

????

Disorders of acid-base regulation

MAY LEAD TO---------

ALKALOSIS--

OR

ACIDOSIS--

Disorders of acid-base regulation cont…

Respiratory acidosis

Respiratory alkalosis

Metabolic acidosis

Metabolic alkalosis

Contd…

Respiratory acid-base disorders are initiated by an increase or decrease in partial pressure of carbondioxide whereas metabolic disorders are initiated by an increase or decrease in bicarbonate ion.

Contd…

Alkalosis - Partial pressure of oxygen increases.

Acidosis – Partial pressure of carbondioxide increases.

Contd…

Respiratory acidosis- Decrease in rate of pulmonary ventilation- Increased pCO2 of ECF.

Respiratory alkalosis- Increased rate of ventilation- Decrease the pCO2

Respiratory acidosis

Figure 27.12a

Respiratory alkalosis

Figure 27.12b

Contd…

Metabolic acidosis- Decreased ECF bicarbonate ion conc.

Metabolic alkalosis- Increased ECF bicarbonate ion conc.

Contd…DISTURBANCE pH PRIMARY

CHANGERATIO SECONDARY

CHANGE

Metabolic Acidosis Decreased Deficit of bi-carbonate

<20 Decrease in PaCO2

MetabolicAlkalosis

Increased Excess of bicarbonate

>20 Increase in PaCO2

Respiratoryacidosis

Decreased Excess of carbonic acid

<20 Increase in bicarbonate

Respiratoryalkalosis

Increased Deficit of carbonic acid

>20 Decrease in bicarbonate

Contd…

Causes - Metabolic acidosis 1. Renal tubular acidosis 2. Diarrhea 3. Vomiting of intestinal contents 4. Diabetes Mellitus 5. Ingestion of acids 6. Chronic renal failure

Contd…

Causes- Metabolic alkalosis 1. Vomiting of gastric contents 2. Ingestion of alkaline drugs etc.

Correction by renal for…

Acidosis- Increased excretion of hydrogen ions and

addition of bicarbonate ions to the ECF.

Alkalosis- Decreased tubular secretion of hydrogen ions

and increased excretion of HCO3_

How can w

e enhance th

e

buffer syst

ems of o

ur

body and balance

pH

thro

ugh nutri

tion??

???

Acid\Alkaline food chartHighly Alkaline Moderately Alkaline Mildly Alkaline Neutral/ Mildly Acidic Moderately

AcidicHighly Acidic

pH 9.5 alkaline water Himalayan salt Grasses Cucumber Kale Kelp Spinach Parsley Broccoli Sprouts(soy, alfalfa etc) Sea Vegetables (Kelp) Green drinks All Sprouted Beans/ Sprouts 

Avocado Beetroot Capsicum/Pepper Cabbage Celery Collard/Spring Greens Endive Garlic Ginger Green Beans Lettuce Mustard Greens Okra Onion Radish Red Onion Rocket/Arugula Tomato Lemon Lime Butter Beans Soy Beans White Haricot Beans Chia/Salba Quinoa  

Artichokes Asparagus Brussels Sprouts Cauliflower Carrot Chives Courgette/Zucchini Leeks New Baby Potatoes Peas Rhubarb Swede Watercress Grapefruit Coconut Buckwheat Spelt Lentils Tofu Other Beans & Legumes Goat & Almond Milk Most Herbs & Spices Avocado Oil Olive Oil Coconut Oil Flax Oil/ Udo’s Oil  

Black Beans Chickpeas/Garbanzos Kidney Beans Seitan Cantaloupe Currants Fresh Dates Nectarine Plum Sweet Cherry Watermelon Amaranth Millet Oats/Oatmeal Spelt Soybeans Rice/Soy/Hemp Protein Freshwater Wild Fish Rice & Soy Milk Brazil Nuts Pecan Nuts Hazel Nuts Sunflower Oil Grapeseed Oil  `

Fresh, Natural Juice Ketchup Mayonnaise Butter Apple Apricot Banana Blackberry Blueberry Cranberry Grapes Mango Mangosteen Orange Peach Papaya Pineapple Strawberry Brown Rice Oats Rye Bread Wheat Wholemeal Bread Wild Rice Wholemeal Pasta Ocean Fish

Alcohol Coffee & Black Tea Fruit Juice (Sweetened) Cocoa Honey Jam Jelly Mustard Miso Rice Syrup Soy Sauce Vinegar Yeast Dried Fruit Beef Chicken Eggs Farmed Fish Pork Shellfish Cheese Dairy Artificial Sweeteners Syrup Mushroom 

EAT MORE -- Alkaline (80%)EAT LESS -- Acidic (20%)

SO WHY NOT CONTROL THE ACID BASE BALANCE

WITH FOOD…???

References

Guyton's medical physiology,(Buffer System)

Ionic changes By Rudolf Jensen

Thank you…

Figure 27.11a

The Central Role of the Carbonic Acid-Bicarbonate Buffer System in

the Regulation of Plasma pH

Figure 27.11b

The Central Role of the Carbonic Acid-Bicarbonate Buffer System in

the Regulation of Plasma pH

Respiratory acid base disorders– Result when abnormal respiratory function causes

rise or fall in CO2 in ECF

Metabolic acid-base disorders– Generation of organic or fixed acids– Anything affecting concentration of bicarbonate ions

in ECF

Acid-Base Disorders

Results from excessive levels of CO2 in body fluids

Respiratory acidosis

Relatively rare condition Associated with hyperventilation

Respiratory alkalosis

Major causes are:– Depletion of bicarbonate reserve– Inability to excrete hydrogen ions at kidneys– Production of large numbers of fixed / organic acids– Bicarbonate loss due to chronic diarrhea

Metabolic acidosis

Figure 27.13

Figure 27.13 The Response to Metabolic Acidosis

Figure 27.14

Figure 27.14 Metabolic Alkalosis

Diagnostic blood tests– Blood pH– PCO2

– Bicarbonate levels Distinguish between respiratory and

metabolic

Detection of acidosis and alkalosis

Animation: Acid-Base Homeostasis

Reduced total body water content Impaired ability to perform renal compensation Increased water demands

– Reduced ability to concentrate urine– Reduced sensitivity to ADH/ aldosterone

Net loss of minerals Inability to perform respiratory compensation Secondary conditions that affect fluid, electrolyte, acid-base

balance

Changes with age include

What is meant by “fluid balance,” “electrolyte balance,” and “acid-base balance”

The compositions of intracellular and extracellular fluids

The hormones that play important roles in regulating fluid and electrolyte balance

The movement of fluid that takes place within the ECF, between the ECF and the ICF, and between the ECF and the environment

You should now be familiar with:

How sodium, potassium, calcium and chloride ions are regulated to maintain electrolyte balance

The buffering systems that balance the pH of the intracellular and extracellular fluids

The compensatory mechanisms involved in acid-base balance

You should now be familiar with:

Thank you…