This document discusses acid-base regulation in the human body. It covers topics such as the carbonic acid-bicarbonate buffer system, respiratory regulation of hydrogen ion concentration, and disorders of acid-base balance like respiratory acidosis and alkalosis and metabolic acidosis and alkalosis. The key roles of the lungs, kidneys, and nutrition in maintaining acid-base homeostasis are also summarized.
6. 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
8. 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
9. 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
10. 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
12. Carbonic Acid-Bicarbonate
Buffering System
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
13. Contd…
Strong base is added
H+ conc. Reduces
NaOH + H2CO3 NaHCO3+H2O
In this way CO2 conc. decreases
This inhibits respiration.
15. 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).
16. 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.
18. 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.
.
19. 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.
20. Protein buffer system
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
.
22. 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.
23. Contd...
At neutral pH the carboxyl ion is present as
COO instead of COOH.
Acidic medium – becomes COOH
Basic medium – becomes COO.
24. 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
27. 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.
28. 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
29. 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
30. Reason
Alveolar ventilation rate decreases
Increases pH
O2 added in blood reduces
Demand of O2 in blood increases
pO2 also decreases
Stimulates ventilation
31. Feedback control of Hydrogen
ion conc. By RS
H conc. Falls below normal
Respiration is depressed
Alveolar ventilation decreases
H increases back to normal
32. 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.
33. 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
34. 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.
35. Contd…
Excretion of hydrogen ions
Reabsorption of bicarbonate ion
Excretion of ammonium ions
39. 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.
40. Contd…
Alkalosis - Partial pressure of oxygen
increases.
Acidosis – Partial pressure of carbondioxide
increases.
41. Contd…
Respiratory acidosis-
Decrease in rate of pulmonary ventilation-
Increased pCO2 of ECF.
Respiratory alkalosis-
Increased rate of ventilation-
Decrease the pCO2
47. Contd…
Causes- Metabolic alkalosis
1. Vomiting of gastric contents
2. Ingestion of alkaline drugs etc.
48. 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_
49.
50.
51. EAT MORE -- Alkaline (80%)
AcidAlkaline food chart
EAT LESS -- Acidic (20%)
Highly Alkaline Moderately Alkaline Mildly Alkaline Neutral/ Mildly Acidic Moderately Highly Acidic
Acidic
pH 9.5 alkaline water Avocado Artichokes Black Beans Fresh, Natural Juice Alcohol
Himalayan salt Beetroot Asparagus Chickpeas/Garbanzos Ketchup Coffee & Black Tea
Grasses Capsicum/Pepper Brussels Sprouts Kidney Beans Mayonnaise Fruit Juice
Cucumber Cabbage Cauliflower Seitan Butter (Sweetened)
Kale Celery Carrot Cantaloupe Apple Cocoa
Kelp Collard/Spring Greens Chives Currants Apricot Honey
Spinach Endive Courgette/Zucchini Fresh Dates Banana Jam
Parsley Garlic Leeks Nectarine Blackberry Jelly
Broccoli Ginger New Baby Potatoes Plum Blueberry Mustard Miso
Sprouts(soy, alfalfa etc) Green Beans Peas Sweet Cherry Cranberry Rice Syrup
Sea Vegetables (Kelp) Lettuce Rhubarb Watermelon Grapes Soy Sauce
Green drinks Mustard Greens Swede Amaranth Mango Vinegar
All Sprouted Beans/ Sprouts Okra Watercress Millet Mangosteen Yeast
Onion Grapefruit Oats/Oatmeal Orange Dried Fruit
Radish Coconut Spelt Peach Beef
Red Onion Buckwheat Soybeans Papaya Chicken
Rocket/Arugula Spelt Rice/Soy/Hemp Protein Pineapple Eggs
Tomato Lentils Freshwater Wild Fish Strawberry Farmed Fish
Lemon Tofu Rice & Soy Milk Brown Rice Pork
Lime Other Beans & Legumes Brazil Nuts Oats Shellfish
Butter Beans Goat & Almond Milk Pecan Nuts Rye Bread Cheese
Soy Beans Most Herbs & Spices Hazel Nuts Wheat Dairy
White Haricot Beans Avocado Oil Sunflower Oil Wholemeal Bread Artificial Sweeteners
Chia/Salba Olive Oil Grapeseed Oil Wild Rice Syrup
Quinoa Coconut Oil ` Wholemeal Pasta Mushroom
Flax Oil/ Udo’s Oil Ocean Fish
52. SO WHY NOT CONTROL THE
ACID BASE BALANCE WITH
FOOD…???
55. The Central Role of the Carbonic
Acid-Bicarbonate Buffer System in
the Regulation of Plasma pH
Figure 27.11a
56. The Central Role of the Carbonic
Acid-Bicarbonate Buffer System in
the Regulation of Plasma pH
Figure 27.11b
57. Acid-Base Disorders
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
60. Metabolic acidosis
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
63. Detection of acidosis and
alkalosis
Diagnostic blood tests
– Blood pH
– PCO2
– Bicarbonate levels
Distinguish between respiratory and
metabolic
Animation: Acid-Base Homeostasis
64. Changes with age include
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
65. You should now be familiar with:
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
66. 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