This document discusses acid-base balance and the mechanisms that regulate pH levels in the human body. It covers topics like buffers, respiratory regulation, and renal regulation of pH. The three main points are:
1) Buffers like bicarbonate help maintain pH levels by neutralizing excess hydrogen ions. The Henderson-Hasselbalch equation describes the buffering capacity of bicarbonate.
2) The respiratory system regulates pH rapidly through exhalation of carbon dioxide. Hemoglobin transports carbon dioxide as bicarbonate from tissues to the lungs.
3) The kidneys regulate pH over longer periods through reabsorption of bicarbonate, and excretion of fixed acids, ammonium
Pka value of weak acid experiment by titrations method PdfSaver
Pka value of weak acid and strong bases by titrations method contains following content
☆aim
☆objective
☆defination of buffers
☆buffer capacity
☆necessity of buffers
☆determination of ph
☆POTENTIOMETRY
☆application of buffer
☆Henderson hasselbalch equation
☆requirement, procedure, formula, calculation, observation table , graph and results
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preparation of buffers, buffers and isotonic systems. Methods for adjustment of tonicity of solutions. Buffers in pharmaceutical and biological systems.
Acid–base homeostasis is the homeostatic regulation of the pH of the body's extracellular fluid (ECF). The proper balance between the acids and bases (i.e. the pH) in the ECF is crucial for the normal physiology of the body, and cellular metabolism. this is detailed study on acid base homeostasis ,explaining definition of terms ,anion gap,ph , mechanism of hydrogen ion homeostasis ,ph of a buffer system , major buffer systems etc.
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Maintenance of pH of body fluids and its disorders for undergraduate medical students and postgraduate students in medicine, paediatrics, respiratory medicine etc
Pka value of weak acid experiment by titrations method PdfSaver
Pka value of weak acid and strong bases by titrations method contains following content
☆aim
☆objective
☆defination of buffers
☆buffer capacity
☆necessity of buffers
☆determination of ph
☆POTENTIOMETRY
☆application of buffer
☆Henderson hasselbalch equation
☆requirement, procedure, formula, calculation, observation table , graph and results
珞Thanku......
preparation of buffers, buffers and isotonic systems. Methods for adjustment of tonicity of solutions. Buffers in pharmaceutical and biological systems.
Acid–base homeostasis is the homeostatic regulation of the pH of the body's extracellular fluid (ECF). The proper balance between the acids and bases (i.e. the pH) in the ECF is crucial for the normal physiology of the body, and cellular metabolism. this is detailed study on acid base homeostasis ,explaining definition of terms ,anion gap,ph , mechanism of hydrogen ion homeostasis ,ph of a buffer system , major buffer systems etc.
please comment
thank u
Maintenance of pH of body fluids and its disorders for undergraduate medical students and postgraduate students in medicine, paediatrics, respiratory medicine etc
The normal ranges for arterial blood gas values
Approach to arterial blood gas interpretation
Arterial blood gas abnormalities in special circumstances
MANAGEMENT OF ATRIOVENTRICULAR CONDUCTION BLOCK.pdfJim Jacob Roy
Cardiac conduction defects can occur due to various causes.
Atrioventricular conduction blocks ( AV blocks ) are classified into 3 types.
This document describes the acute management of AV block.
Flu Vaccine Alert in Bangalore Karnatakaaddon Scans
As flu season approaches, health officials in Bangalore, Karnataka, are urging residents to get their flu vaccinations. The seasonal flu, while common, can lead to severe health complications, particularly for vulnerable populations such as young children, the elderly, and those with underlying health conditions.
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This year, the flu season is expected to coincide with a potential increase in other respiratory illnesses. The Karnataka Health Department has launched an awareness campaign highlighting the significance of flu vaccinations. They have set up multiple vaccination centers across Bangalore, making it convenient for residents to receive their shots.
To encourage widespread vaccination, the government is also collaborating with local schools, workplaces, and community centers to facilitate vaccination drives. Special attention is being given to ensuring that the vaccine is accessible to all, including marginalized communities who may have limited access to healthcare.
Residents are reminded that the flu vaccine is safe and effective. Common side effects are mild and may include soreness at the injection site, mild fever, or muscle aches. These side effects are generally short-lived and far less severe than the flu itself.
Healthcare providers are also stressing the importance of continuing COVID-19 precautions. Wearing masks, practicing good hand hygiene, and maintaining social distancing are still crucial, especially in crowded places.
Protect yourself and your loved ones by getting vaccinated. Together, we can help keep Bangalore healthy and safe this flu season. For more information on vaccination centers and schedules, residents can visit the Karnataka Health Department’s official website or follow their social media pages.
Stay informed, stay safe, and get your flu shot today!
Tom Selleck Health: A Comprehensive Look at the Iconic Actor’s Wellness Journeygreendigital
Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
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Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
Early Life and Career
Childhood and Athletic Beginnings
Tom Selleck was born on January 29, 1945, in Detroit, Michigan, and grew up in Sherman Oaks, California. From an early age, he was involved in sports, particularly basketball. which played a significant role in his physical development. His athletic pursuits continued into college. where he attended the University of Southern California (USC) on a basketball scholarship. This early involvement in sports laid a strong foundation for his physical health and disciplined lifestyle.
Transition to Acting
Selleck's transition from an athlete to an actor came with its physical demands. His first significant role in "Magnum P.I." required him to perform various stunts and maintain a fit appearance. This role, which he played from 1980 to 1988. necessitated a rigorous fitness routine to meet the show's demands. setting the stage for his long-term commitment to health and wellness.
Fitness Regimen
Workout Routine
Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
Selleck adjusted his fitness routine as he aged to suit his body's needs. Today, his workouts focus on maintaining flexibility, strength, and cardiovascular health. He incorporates low-impact exercises such as swimming, walking, and light weightlifting. This balanced approach helps him stay fit without putting undue strain on his joints and muscles.
Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
New Directions in Targeted Therapeutic Approaches for Older Adults With Mantl...i3 Health
i3 Health is pleased to make the speaker slides from this activity available for use as a non-accredited self-study or teaching resource.
This slide deck presented by Dr. Kami Maddocks, Professor-Clinical in the Division of Hematology and
Associate Division Director for Ambulatory Operations
The Ohio State University Comprehensive Cancer Center, will provide insight into new directions in targeted therapeutic approaches for older adults with mantle cell lymphoma.
STATEMENT OF NEED
Mantle cell lymphoma (MCL) is a rare, aggressive B-cell non-Hodgkin lymphoma (NHL) accounting for 5% to 7% of all lymphomas. Its prognosis ranges from indolent disease that does not require treatment for years to very aggressive disease, which is associated with poor survival (Silkenstedt et al, 2021). Typically, MCL is diagnosed at advanced stage and in older patients who cannot tolerate intensive therapy (NCCN, 2022). Although recent advances have slightly increased remission rates, recurrence and relapse remain very common, leading to a median overall survival between 3 and 6 years (LLS, 2021). Though there are several effective options, progress is still needed towards establishing an accepted frontline approach for MCL (Castellino et al, 2022). Treatment selection and management of MCL are complicated by the heterogeneity of prognosis, advanced age and comorbidities of patients, and lack of an established standard approach for treatment, making it vital that clinicians be familiar with the latest research and advances in this area. In this activity chaired by Michael Wang, MD, Professor in the Department of Lymphoma & Myeloma at MD Anderson Cancer Center, expert faculty will discuss prognostic factors informing treatment, the promising results of recent trials in new therapeutic approaches, and the implications of treatment resistance in therapeutic selection for MCL.
Target Audience
Hematology/oncology fellows, attending faculty, and other health care professionals involved in the treatment of patients with mantle cell lymphoma (MCL).
Learning Objectives
1.) Identify clinical and biological prognostic factors that can guide treatment decision making for older adults with MCL
2.) Evaluate emerging data on targeted therapeutic approaches for treatment-naive and relapsed/refractory MCL and their applicability to older adults
3.) Assess mechanisms of resistance to targeted therapies for MCL and their implications for treatment selection
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
Prix Galien International 2024 Forum ProgramLevi Shapiro
June 20, 2024, Prix Galien International and Jerusalem Ethics Forum in ROME. Detailed agenda including panels:
- ADVANCES IN CARDIOLOGY: A NEW PARADIGM IS COMING
- WOMEN’S HEALTH: FERTILITY PRESERVATION
- WHAT’S NEW IN THE TREATMENT OF INFECTIOUS,
ONCOLOGICAL AND INFLAMMATORY SKIN DISEASES?
- ARTIFICIAL INTELLIGENCE AND ETHICS
- GENE THERAPY
- BEYOND BORDERS: GLOBAL INITIATIVES FOR DEMOCRATIZING LIFE SCIENCE TECHNOLOGIES AND PROMOTING ACCESS TO HEALTHCARE
- ETHICAL CHALLENGES IN LIFE SCIENCES
- Prix Galien International Awards Ceremony
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
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Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
Anti ulcer drugs and their Advance pharmacology ||
Anti-ulcer drugs are medications used to prevent and treat ulcers in the stomach and upper part of the small intestine (duodenal ulcers). These ulcers are often caused by an imbalance between stomach acid and the mucosal lining, which protects the stomach lining.
||Scope: Overview of various classes of anti-ulcer drugs, their mechanisms of action, indications, side effects, and clinical considerations.
2. Metabolic reactions are influenced by pH (hydrogen ion
concentration)
Any change in pH causes :
Distortion of protein structure
Enzyme activity is affected
Electrolytes can be affected
Hence any change in pH is closely guarded.
pH of Blood(ECF): 7.35-7.45
pH of ICF depends upon tissues
RBC: 7.2, Skeletal Muscle: 6.0
Hence 6.8-7.8 is appropriate for life
3. According to Bronsted and Lowry, Acids are substances that are
capable of Donating Protons and Bases are those that Accept
Protons. Acids are proton donors and bases are proton acceptors.
Acids and Bases Definition
Acids Bases
HA H+ + A– NH3 + H+ NH+
4
HCl H+ + Cl– HCO3
– +H+
H2CO3
H2CO3 H+ +
HCO3
–
4.
5. Term Definition and explanations
pH Negative logarithm of hydrogen ion
concentration.
Normal value 7.4 (range 7.38 -7.42)
Acids Proton donors; pH <7
Bases Proton acceptors; pH > 7
Strong acids Acids which ionize completely; e.g. HCl
Weak acids Acids which ionize incompletely e.g. H2CO3
pK value pH at which the acid is half ionized; Salt : Acid
= 1:1
Alkali reserve Bicarbonate available to neutralise acids;
Normal 24 mmol/L (range 22-26 mmol/L)
Buffers Solutions minimise changes in pH
Terms Explained
6. Strong acids dissociate completely in solution, while weak
acids ionize incompletely
HCl H+ + Cl–- (Complete)
H2CO3 H+ + HCO3
–- (Partial)
In a solution of HCl, almost all the molecules dissociate and exist as
H+ and Cl– ions. Hence the concentration of H+ is very high and it is
a strong acid.
But in the case of a weak acid (e.g. acetic acid),
it will ionize only partially. So, the number of acid molecules existing
in the ionized state is much less, may be only 50%.
Weak and Strong Acids the Extent of Dissociation
7. Dissociation of an acid is a freely reversible reaction. At equilibrium
the ratio between dissociated and undissociated particle is a constant.
Dissociation constant (Ka) of an acid is
[H+] [A–-]
Ka = ––––––––-
[HA]
where [H+] is the concentration of hydrogen ions, [A–] = the
concentration of anions or conjugate base, and [HA] is the
concentration of undissociated molecules.
The pH at which the acid is half ionized is called pKa of an acid
which is constant at a particular temperature and pressure.
Strong acids will have a low pKa and weak acids have a higher pKa.
Dissociation Constant
8. The acidity of a solution is measured by noting the hydrogen ion
concentration in the solution and obtained by the equation.
[acid] [HA]
[H+] = Ka –––––––– or ––––––
[base] [A––]
where Ka is the dissociation constant.
To make it easier, Sorensen expressed the H+ concentration as the
negative of the logarithm (logarithm to the base 10) of hydrogen ion
concentration, and is designated as the pH. Therefore,
_1_
pH = –log [H+] = log [H+]
Acidity of a Solution and pH
9. Thus the pH value is inversely proportional to the acidity.
Lower the pH, higher the acidity or hydrogen ion concentration.
Higher the pH, the acidity is lower.
The pH 7 indicates the neutral pH
11. The relationship between pH, pKa, concentration of acid and
conjugate base (or salt) is expressed by the
Henderson-Hasselbalch equation,
[base] [salt]
pH = pKa + log ––––– or pH = pKa + log –––––
[acid] [acid]
When [base] = [acid]; then pH = pKa
Therefore, when the concentrations of base and acid are the same,
then pH is equal to pKa.
The Effect of Salt upon the Dissociation
12. The pH of a buffer on addition of a known quantity of acid and alkali
can, therefore, be predicted by the equation.
Moreover, the concentration of salt or acid can be found out by
measuring the pH.
The Henderson-Hasselbalch’s equation, therefore, has great practical
application in clinical practice in assessing the acid-base status, and
predicting the limits of the compensation of body buffers.
Clinical Application of Henderson-Hasselbalch’s Equation
13. Buffers are solutions which can resist changes in pH when acid or
alkali is added.
Buffers are of two types:
a. Mixtures of weak acids with their salt with a strong base or
b. Mixtures of weak bases with their salt with a strong acid.
i. H2CO3 / NaHCO3 (Bicarbonate buffer)
(carbonic acid and sodium bicarbonate)
ii. CH3COOH / CH3COONa (Acetate buffer)
(acetic acid and sodium acetate)
iii. Na2HPO4 / NaH2PO4 (Phosphate buffer)
Buffers
14. The buffering capacity of a buffer is defined as the ability of
the buffer to resist changes in pH when an acid or base
is added.
Buffer capacity is determined by the actual concentrations of salt and
acid present, as well as by their ratio.
Buffering capacity is the number of grams of strong acid or alkali
which is necessary for a change in pH of one unit of one liter of
buffer solution.
Factors Affecting Buffer Capacity
15. Buffer solutions consist of mixtures of a weak acid or base
and its salt.
When hydrochloric acid is added to the acetate buffer, the salt reacts
with the acid forming the weak acid, acetic acid and its salt.
CH3–COONa + HCl ® CH3–COOH + NaCl
Thus changes in the pH are minimized.
Similarly when a base is added, the acid reacts with it forming salt
and water.
CH3–COOH + NaOH ® CH3–COONa + H2O
How do Buffers Act?
16. But the pH of the buffer is dependent on the relative
proportion of the salt and acid (Henderson-Hasselbalch's
equation).
The pH of a buffer on addition of a known quantity of acid and
alkali can, therefore, be predicted by the equation.
The Henderson-Hasselbalch's equation therefore, has great
practical application in clinical practice in assessing the acid-
base status, and predicting the limits of the compensation of
body buffers.
The Buffer Capacity is Determined by the Absolute
Concentration of the Salt and Acid
18. Normal pH of plasma is 7.4.
In normal life, the variation of plasma pH is very small.
The pH of plasma is maintained within a narrow range of 7.35 to
7.45.
The pH of the interstitial fluid is generally 0.5 units below that of
the plasma.
Acid-base Balance
19. If the pH is below 7.38, it is called acidosis. Life is threatened
when the pH is lowered below 7.25.
Acidosis leads to CNS depression and coma. Death occurs
when pH is below 7.0.
When the pH is more than 7.42, it is alkalosis. It is very
dangerous if pH is increased above 7.55.
Alkalosis induces neuromuscular hyperexcitability and tetany.
Death occurs when the pH is above 7.6.
20. Volatile acid is carbonic acid which is a weak acid.
The metabolism produces nearly 50 mmoles of carbonic
acid per day which is equal to 500 ml of sulphuric acid.
60-80 mEq of fixed acids per day.
Nonvolatile (fixed) acids are lactate, keto acids, sulfuric acid
and phosphoric acid.
1 mol of glucose produces 2 mols of lactic acid.
Volatile and Fixed Acids
21. The dietary protein content decides the amount of sulfuric and
phosphoric acids.
The sulfoproteins yield sulfuric acid and phosphoproteins and
nucleoproteins produce phosphoric acid.
On an average about 3g of phosphoric acid and about 3g sulfuric
acid are produced per day.
The carbonic acid, being volatile, is eliminated as CO2 by the
lungs.
The fixed acids are buffered and later on the H+ are excreted by
the kidney.
Volatile and Fixed Acids
22. 22
Normal human diet is almost neutral, but H ions are generated
because of various metabolic reactions.
1. Aerobic Metabolism:
Carbon, Hydrogen, Oxygen converted to Water and CO2
(20,000 mmol/day). This CO2 is responsible for generation
of Hydrogen ions
2. Lactic Acid: Anerobic Respiration
3. Phosphoric Acid: via Phospholipids
4. Sulphuric acids: sulphur containing Amino Acids
5. Keto Acids: lipid metabolism (approx 80 mEq/day).
From 2 – 5 are Non-Volatile Acids
GI secretions are acidic in nature and Non-GI secretions are
alkaline in nature.
24. There are three lines of defence operative in maintaining the blood pH.
HYDROGEN-ION HOMEOSTASIS
I. Buffer systems
II. Respiratory mechanism
III. Renal regulation
25. Buffers are the solutions which resist change in pH by the
addition of small amounts of acids or bases. Any substance that
can reversibly bind hydrogen ions can be labelled as a buffer.
Buffers can neither remove H+ ions from the body nor add them
to it. They can only keep H+ ions in a temporarily suspended
form. The H+ ions have to be ultimately eliminated by the kidneys
BUFFER SYSTEMS
26. There are three major buffer systems operative in the human body.
1. Bicarbonate buffer
2. Phosphate buffer
3. Protein buffer
27. Bicarbonate and carbonic acid pair (NaHCO3/H2CO3) is the
predominant buffer system in the extracellular fluid.
The concentration of the bicarbonate ion is not directly measured, it is
calculated from the Henderson–Hasselbalch equation.
BICARBONATE BUFFER
28. The above equation is popularly known as the Henderson–Hasselbalch
equation and is applicable for any buffer pair.
…Continues)
(Continued…
29. The Henderson–Hasselbalch equation for the bicarbonate buffer pair is
Substitute the values discussed earlier in the above equation (plasma pH = 7.4;
pKa for H2CO3 = 6.1; HCO3
– = 24 mmol/L; H2CO3 = 1.2 mmol/L).
(Continued…
31. It is conclusive from the above discussion that the concentration of
bicarbonate is almost 20 times more than that of carbonic acid in the
blood. This is referred to as the alkali reserve and is essential to meet
the challenge of buffering the H+ ions generated from the huge body
acid–load.
32. 32
Alkali Reserve:
▪ Plasma Bicarbonate (HCO3– ) represents the alkali
reserve and it has to be sufficiently high to meet the acid
load.
▪ If it was too low to give a ratio of 1, all the HCO3– would
have been exhausted within a very short time; and
buffering will not be effective.
▪ So, under physiological circumstances, the ratio of 20:1
(a high alkali reserve) ensures high buffering efficiency
against acids
33. 33
Phosphate Buffer:
Intracellular Buffer
Na2HPO4 (Disodium Hydrogen Phosphate-
NaH2PO4 (Sodium Dihydrogen Phosphate)
Mostly 5% of total buffering capacity but
effective because pKa is 6.8 hich is close to
pH of blood 7.4.
Base to acid Ratio is 4
34. 34
Protein Buffer:
albumin and Hemoglobin acts as a buffer
Buffering capacity depends on pKa of amino acids
and their ionizable groups
For eg : Histidine of Hb is having pka of 6.7 which
makes it as a buffer
Buffers have limited pH maintenance because H
ions are not added or removed
36. The respiratory system and the kidneys together maintain the body pH.
The respiratory response to the altered plasma pH is very swift (within
minutes) compared to the slow but steady response of the kidneys (hours
to days).
Respiratory system provides a rapid mechanism for the maintenance of
acid-base balance. This is achieved by regulating the concentration of
carbonic acid (H2CO3) in the blood
RESPIRATORY REGULATION OF PH
(Continued…
37. 37
The large volumes of CO2 produced by the cellular metabolic activity
endanger the acid base equilibrium of the body. But in normal
Circumstances all of this CO2 is eliminated from the body in the expired air
via the lungs.
Hemoglobin as a buffer : Haemoglobin of erythrocytes is also important in
the respiratory regulation of pH. At the tissue level, hemoglobin binds to H+
ions and helps to transport CO2 as HCO3 with a minimum change in pH
(referred to as Isohydric transport).
In the lungs, as hemoglobin combines with H+ ions are removed which
combine with HCO3 to form H2CO3 which after dissociates to release CO2
to be exhaled
38. 38
Generation of HCO3 by RBC :
Due to lack of aerobic metabolic pathways, RBC produce very little CO2.
The plasma CO2 diffuses into the RBC along the concentration gradient
where it combines with water to form H2CO3. This reaction is catalysed by
carbonic anhydrase.
In the RBC, H2CO3 dissociates to produce H+ and HCO3 .
The H+ ions are trapped and buffered by hemoglobin. As the
concentration of HCO3 increases in the RBC, it diffuses into plasma along
with the concentration gradient, in exchange for Cl- ions, to maintain
electrical neutrality. This phenomenon, referred to as chloride shift, helps
to generate HCO3
40. RENAL REGULATION OF pH
Regulation of pH by the kidneys is permanent mechanism of
pH balance. The pH of blood is 7.4 and Urine is 6.0 this
explains Kidney acidifies urine to maintain pH.
It excretes Hydrogen ions or retains them, and maintain alkali
reserve of the body.
41. 41
The basic mechanisms of renal regulation of pH include:
1. Reabsorption of bicarbonate
2. Excretion of Fixed Acids
3. Excretion of ammonium ions
4. Excretion of free H+ ions.
43. This mechanism is primarily responsible to conserve the blood HCO3,
with a simultaneous excretion of H+ ions. The normal urine is almost free
from HCO3.
43
45. 45
Fixed acids are also excreted in the form of sodium dihydrogen phosphate.
Titratable acidity is a measure of acid excreted into urine by the kidney
which is number of ml of 0.1 N NaOH required to titrate 1 L of urine to pH
7.4.
This can be estimated by titrating urine back to the normal pH of blood.
Titratable acidity reflects the H+ ions excreted into urine which resulted in a
fall of pH from 7.4.
The excreted H+ ions are actually buffered in the urine by phosphate buffer.
H + ion is secreted into the tubular lumen in exchange for Na+ ion.
46. 46
This Na+ is obtained from the base, disodium hydrogen
phosphate (Na2HPO4). The latter in turn combines with H+
to produce the acid, sodium dihydrogen phosphate
(NaH2PO4), in which form the major quantity of titratable
acid in urine is present.
As the tubular fluid moves down the renal tubules/ more and
more H+ ions are added, resulting in the acidification of
urine.
This causes a fall in the pH of urine to as low as 4.5.
48. 48
This is another mechanism to buffer H+ ions secreted into the tubular
fluid.
The H+ ion combines with NH3 to form ammonium ion.
The renal tubular cells de-amidate glutamine to glutamate and NH3. This
reaction is catalysed by the enzyme glutaminase
The NH3, liberated in this reaction, diffuses into the tubular lumen where
it
combines with H+ to form NH4.
Ammonium ions cannot diffuse back into tubular cells and, therefore, are
excreted into urine.
NH4 is a major urine acid.
50. 50
Excretion of H+ ions
Kidney is the only route through which the H+ can be eliminated from the body.
H+ excretion occurs in the PCT( renal tubular cells) and is coupled with the
regeneration of HCO3
-
Carbonic anhydrase catalyses the production of carbonic acid (H2CO3) from CO2
and H2O in the renal tubular cell.
H2CO3 then dissociates to H+ and HCO3
- . The H+ ions are secreted into the
tubular lumen in exchange for Na+.
The Na+ in association with HCO3
- is reabsorbed into the blood.
This is an effective mechanism to eliminate acids (H+) from the body with a
simultaneous generation of HCO3
-.
The H+ combines with a non-carbonate base and is excreted in urine.