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Questions and Answers
Which of the following diseases can decrease the production rate of red blood cells (RBC)?
What is a potential result of haemolysis in the body?
Which of the following substances is known to decrease the activity of blood-forming tissues?
Which gas competes with oxygen for binding sites on hemoglobin, leading to reduced oxygen availability?
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What dietary components are essential to support the production of red blood cells?
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What is the primary component of haemoglobin responsible for carrying oxygen?
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Which type of haemoglobin is found predominantly in normal adult blood?
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Which vitamins and minerals are essential for haemoglobin synthesis?
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What role does myoglobin play in muscle tissues?
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What happens to foetal haemoglobin (HbF) after birth?
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How many polypeptide chains are present in a single haemoglobin molecule?
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Which factor does NOT directly affect the synthesis of haemoglobin in the bone marrow?
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How does myoglobin compare to haemoglobin in terms of oxygen binding strength?
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What process describes the movement of oxygen from an area of high concentration to an area of low concentration?
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What is the primary molecule that oxygen binds to in the blood?
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How many oxygen molecules can one haemoglobin molecule bind to at maximum?
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In which location does oxygen generally flow from the blood to tissues?
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What form of haemoglobin is favored when oxygen is released in the tissues?
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What increases the concentration of oxygen in the alveoli of the lungs?
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What happens to the iron (Fe2+) atoms in haemoglobin when oxygen pressure is high?
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What is the direction of carbon dioxide diffusion in relation to blood concentration?
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What is the normal pH range of urine excreted by the kidneys?
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Which of the following is a cause of acidosis?
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Which mineral belongs to the macrominerals group?
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What is the principal cation in extracellular fluid?
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How does the body primarily lose water?
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Which process is NOT involved in conserving fixed bases in the kidneys?
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What percentage of body water is stored intracellularly?
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Which of the following is an example of a micromineral?
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What does the presence of protein in urine indicate?
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Which condition is associated with the presence of glucose in urine?
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What is the primary water content percentage in urine?
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What is the normal range for urine pH?
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What does a fruity odor in urine typically indicate?
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Which abnormal constituent in urine indicates an obstruction in the bile flow?
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In which condition is the specific gravity of urine likely to be low?
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Elevated levels of uric acid in urine can indicate which of the following?
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Which of the following is a result of hemolysis of red blood cells?
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What does the term oliguria refer to?
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What does the presence of ketone bodies in urine signify?
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What is the function of testing urine with Benedict's reagent?
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What does an offensive odor in urine typically suggest?
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Study Notes
Haemoglobin
- Red pigment in red blood cells that transports oxygen to tissues
- Conjugated protein containing globin (protein part) and haem (iron containing part)
- Synthesized in the bone marrow
- Haemoglobin synthesis is dependent on iron, folic acid, vitamin B12, and amino acids
- Deficiency of any of these factors can decrease the ability of the bone marrow to synthesize haemoglobin
- Each haemoglobin molecule contains 4 polypeptide chains and 4 haem molecules
- Each haem molecule is located in a pocket formed by the folding of the polypeptide chain
- Haem contains a porphyrin ring with one iron (Fe2+) atom at the center
- Oxygen binds to the Fe2+ atoms of the haem
- CO2 binds to the α-amino group of the N-terminal end of the polypeptide chain
Types of Haemoglobin
- Normal adult blood is composed of two types of haemoglobin: HbA1 (97% of total Hb) and HbA2 (3% of total Hb)
- Foetuses and newborns contain another type of haemoglobin called foetal haemoglobin (HbF)
- HbF binds oxygen more tightly than adult haemoglobin, allowing foetuses to draw oxygen from their mothers' blood
- Foetal haemoglobin transforms to normal haemoglobin soon after birth
Myoglobin
- Globular protein similar to haemoglobin (contains haem group)
- Haemoglobin transports oxygen to tissues, while myoglobin stores oxygen in red muscle tissues like the heart muscle
- Myoglobin binds oxygen more strongly than haemoglobin
- Myoglobin is a monomeric protein
- Under conditions of oxygen deprivation, myoglobin releases oxygen to the heart muscle for the synthesis of ATP
Transportation of Oxygen and Carbon Dioxide
- Oxygen is carried from the lungs to the tissues by haemoglobin in the blood.
- Carbon dioxide is carried from the tissues to the lungs by haemoglobin in the blood.
- Gases always diffuse from an area of high concentration to one of lower concentration.
- Inspired air has a higher concentration of oxygen than blood in the alveoli of the lungs.
- Cells have a higher concentration of carbon dioxide than blood.
Oxygen Transportation
- Oxygen binds to the Fe2+ atoms of the haem portion of the haemoglobin (HHb) molecule to form oxyhaemoglobin (HbO2-).
- Since each haemoglobin molecule has 4 haem groups, each haemoglobin molecule can bind a total of four oxygen molecules.
- When oxygen enters the lungs, the oxygen pressure is high, making all the Fe2+ ions in haemoglobin saturated with oxygen molecules
- Oxygen is carried from the lungs to the tissues as oxyhaemoglobin.
- In the tissues, the oxygen pressure is low, causing oxygen to flow from arterial blood to tissues.
- The release of oxygen in the tissues favours the deoxygenated form of haemoglobin.
Carbon Dioxide Transportation
- Carbon dioxide in the blood is transported in three ways:
- Dissolved in plasma (5- 10%)
- Combined with haemoglobin to form carbaminohaemoglobin (20-30%)
- As bicarbonate (HCO3-) ions (60-70%)
Acid-Base Balance
- Kidneys maintain acid-base balance through:
- Excreting acidic or basic urine (pH range 4.5-9.5)
- Reabsorption, secretion, or excretion of non-volatile acids (e.g., lactic acid, pyruvic acid)
- Conserving fixed bases through the production of ammonia (acid substances in the blood combine with ammonia and are excreted as ammonium salts, which saves sodium and potassium ions)
Acidosis
- pH falls below 7.35
- Causes include uncontrolled diabetes with ketosis, severe exercise, renal failure, poisoning with acid, severe diarrhoea, and severe dehydration
Alkalosis
- pH of blood rises above 7.45
- Causes include prolonged vomiting, gastric suction, renal disease, massive blood transfusions, and diuretic therapy
Fluid Electrolyte Balance
- Normally, water intake is balanced by water output.
- Oedema: intake exceeds output.
- Dehydration: output exceeds intake.
Water Balance
-
The body replenishes its water supply through:
- Ingestion of liquids
- Ingestion of foods
- Metabolic processes taking place in the body
-
The body loses water through:
- Kidneys (urine)
- Skin (perspiration)
- Lungs (exhaled moisture)
- Faeces
Distribution of Water in the Body
- Two major areas:
- Intracellular (55%)
- Extracellular (45%)
Electrolyte Balance
- Ions are divided into 2 groups:
- Cations (positively charged ions):
- Na+, K+, Mg2+, Ca2+
- Anions (negatively charged ions):
- Cl-, HCO3-, PO43-, etc.
- Principal cation in intracellular fluid is potassium.
- Principal cation in the extracellular fluid is sodium.
- Cations (positively charged ions):
Mineral Cations and Anions
- Minerals required for the body can be divided into two main groups:
- Macrominerals:
- Required in amounts greater than 100mg per day
- Sodium ions, Potassium ions, Calcium ions, Magnesium ions, Chloride ions & Phosphate ions
- Microminerals (Trace Elements):
- Required in amounts less than 100mg per day
- Iron ions, Copper ions, Zinc ions etc
- Macrominerals:
Urine - General Properties
- Slightly acidic
- pH varies to compensate for diet and products of metabolism (pH range 4.5-8)
- Pale yellow to amber colour
- Colour intensity correlates with urine concentration
- Freshly voided urine is clear
- Distinctive odour (aromatic odour due to aromatic acids in normal urine)
- Specific gravity measures the amount of substances dissolved in urine
- The greater the concentration of solutes, the greater the density.
- Specific gravity is a measure of the kidney's ability to concentrate urine.
- If kidneys make urine with a high amount of water, urine has a low specific gravity.
Urine Composition
- Urine is a complex fluid composed of 95% water and 5% solids.
- Urine contains end products of metabolism carried out by the cells in the body.
- Almost all substances in urine are also in the blood (but at different concentrations).
Urine Constituents - Organic
- Urea: end product of protein metabolism
- Uric acid: Product of metabolism of purines from nucleoproteins
- Increased output in leukemia, severe liver disease, various stages of gout
- Deposits of uric acid in joints are characteristic of gout
- Under certain conditions, it can crystallize in the kidneys, forming kidney stones.
- Creatine: Produced in the body from three amino acids (arginine, methionine & glycine)
- Usually present in muscle, brain and blood
- Creatinuria: Abnormal amounts of creatine in the urine May occur during starvation, diabetes mellitus & prolonged fevers
- Creatinine: Product of the breakdown of creatine
- Small amounts of vitamins, other hormones & enzymes
Urine Constituents - Inorganic
- Chloride ions: Varies with intake of NaCl (Excretion decreased in fevers)
- Sodium ions: Varies with intake and body's requirements
- Phosphates: Depends on diet (Increased when diet contains food high in phosphorus)
- Sulphates: Derived from metabolism of sulfur-containing proteins (Influenced by diet)
- Ammonium Ions: Derived from the hydrolysis of urea
- Other Ions: Calcium, magnesium and potassium
Urine Constituents - Abnormal
- Protein:
- Urine should not normally contain protein.
- Proteinuria: Presence of protein in urine (kidney disease)
- Test for proteins in urine based on the fact that protein coagulates when heated.
- Glucose:
- Glucosuria: Presence of glucose in urine
- Test with Benedict’s reagent
- May be found in urine after heavy muscular exercise, a meal high in carbohydrates, diabetes mellitus or liver damage.
- Other sugars:
- Lactose & galactose during pregnancy and lactation
- Ketone Bodies: During diabetes mellitus, starvation or inadequate carbohydrate intake.
- Kidneys produce more ammonia to neutralize the ketone bodies.
- Blood:
- Haematuria: Presence of blood in the urine
- Result from lesions or stones in the kidneys/ urinary tract.
- Haemoglobinuria: Presence of haemoglobin in the urine
- Result from haemolysis of RBC caused by injection of hypotonic solution, severe burns, or blackwater fever.
- Phenylpyruvic acid: Intermediate product in the metabolism of the essential amino acid phenylalanine.
- Present in the urine of a person with Phenylketonuria.
- Haematuria: Presence of blood in the urine
- Bile: Indicates obstruction of flow to the intestines
- Bilirubin: Bile pigments not normally present in urine. Present in patients with conjugated hyperbilirubinemia.
- Urobilinogen: Indicative of haemolytic jaundice
- Creatine: Normally small amounts of creatine are present in urine. Elevated levels are indicative of muscle wasting disease.
- Uric Acid: Elevated levels can indicate gout.
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Description
This quiz explores the structure, synthesis, and types of haemoglobin, including its critical role in oxygen transport within red blood cells. It covers the biochemical components necessary for haemoglobin formation and the differences between adult and fetal haemoglobin. Test your knowledge on this essential protein and its functions!
