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this is all about buffer system and human physiology
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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…