Bock 1 (+ incorporated muscle theory)

To determine osmotic resistance, use centrifuge tubes marked with NaCl concentrations, add blood, incubate, and centrifuge. Clear supernatant indicates no hemolysis, while reddish supernatant indicates hemolysis.

The osmotic resistance of blood equals the NaCl concentration of the most diluted solution with a clear supernatant and red precipitate. The concentration of the most concentrated solution without a red precipitate indicates the limit of complete hemolysis.

In myogenic lesions, the amplitude of the motor unit potential and maximal contraction is smaller than normal, with no resting/spontaneous activity (isoelectric line during relaxation). Complete interference is present but with small amplitude.

A large amplitude with no complete interference during maximal contraction indicates a neurogenic lesion.

In a neurogenic lesion, there is spontaneous activity characterized by fibrillation and fasciculation, leading to increased size of motor units over time due to regeneration, resulting in larger motor potentials (amplitude and duration).

Insertional activity is normal in healthy muscle, increased in neurogenic lesions, and normal in myogenic lesions, but can also be increased in cases of myopathy or polymyositis.

In neurogenic lesions, spontaneous activity includes fibrillation and positive waves. In myogenic lesions, spontaneous activity can also include fibrillation and positive waves, but it is less common.

In neurogenic lesions, motor unit potentials are large with limited recruitment. In myogenic lesions, motor unit potentials are small with early recruitment.

In normal conditions, the interference pattern is full. In neurogenic lesions, it is reduced with a fast firing rate, while in myogenic lesions, it is reduced with a slow firing rate, and both can show full low amplitude patterns.

Smooth muscle cells are 1-5 um in diameter and 20-500 um in length. They are composed of myocytes, which are thin elongated cells with a single nucleus, containing organelles like mitochondria and filaments (actin and myosin). The arrangement of actin and myosin filaments differs from that in skeletal muscle, with actin filaments attached to dense bodies, which serve a similar role to Z-disks in skeletal muscle.

The two types of smooth muscle are:

1. Multi-unit smooth muscle:

   • Cells function separately.
   • Contraction is initiated by a transmitter, not by action potentials.
   • Examples: uterus, respiratory muscles (bronchi, bronchioles).

2. Single-unit smooth muscle:

   • Cells form a functional unit with stimuli spreading through gap junctions.
   • Contractions are usually caused by action potentials (phasic contractions).
   • Examples: pupillary muscle (pupillary sphincter and dilator muscle), arrector pili.

Smooth muscle can contract as much as 80 percent of its length, while skeletal muscle can only contract about 30 percent of its length. This is due to the unique arrangement of actin and myosin filaments in smooth muscle, allowing for more extensive contraction.

Smooth muscle contraction is initiated by calmodulin, which binds calcium ions and activates myosin light chain kinase (MLCK).

In smooth muscle, most calcium ions needed for contraction come from the extracellular space, while in skeletal muscle, calcium ions are primarily produced by the sarcoplasmic reticulum.

The ratio of actin to myosin in smooth muscle is 15/1, whereas in skeletal muscle it is 2/1.

Neurotransmitters from vegetative nerves can cause smooth muscle contraction by being released into the interstitial fluid and acting on the muscle fibers.

The two types of action potentials in smooth muscle are those with a plateau phase (e.g., arteries) and those without a plateau phase (e.g., antrum pyloricum).

Glial cells contribute to the function of neurons by:

• Forming a myelin sheath around axons
• Increasing membrane resistance
• Providing electrical isolation
• Maintaining extracellular homeostasis

The nodes of Ranvier are significant in myelinated fibers because they allow for saltatory conduction, where excitation spreads rapidly from one node to the next, resulting in higher conduction velocity. The nodes contain rapid Na+ channels, while the membrane under the myelin sheath contains mostly rapid K+ channels.

Myelination increases conduction velocity in neurons because it allows for saltatory conduction, where action potentials jump from one node of Ranvier to another, leading to faster transmission of electrical impulses compared to unmyelinated fibers.

Oligodendrocytes.

Axon hillock.

From the axon hillock.

The rapid voltage gated Na⁺-channels have 2 gates: an activation gate (faster) and an inactivation gate (slower). Ion flow occurs only if both gates are opened. The activation gate is closed during resting potential and opens rapidly by depolarization when the threshold is reached. The inactivation gate is closed by depolarization.

The sodium-potassium ATPase pumps 3 Na+ ions out of the cell and 2 K+ ions in at the cost of one ATP, maintaining the concentration gradient necessary for resting membrane potential.

There are two types of postsynaptic potentials:

1. Excitatory Postsynaptic Potentials (EPSP): Causes depolarization, making the neuron more likely to generate an action potential.
2. Inhibitory Postsynaptic Potentials (IPSP): Causes hyperpolarization, making the neuron less likely to generate an action potential.

The end plate potential (EPP) is a depolarization of skeletal muscle fibers caused by neurotransmitters binding to the postsynaptic membrane at the neuromuscular junction. One EPP is sufficient to cause contraction in the post-synaptic skeletal muscle cell, unlike one EPSP which is not enough to trigger an action potential.

Action potential is generated by voltage-gated ion channels that change the membrane potential without significantly altering ion concentrations.

The all or none law states that if an action potential occurs, it is propagated to every part of the membrane, and its amplitude does not change with increasing stimulus intensity.

Fast voltage-gated sodium channels can be blocked by local anesthetic drugs such as lidocaine and tetrodotoxin (TTX).

Fast voltage-gated potassium channels are located everywhere under the myelin sheath.

Voltage-gated potassium channels can be inhibited by tetraethylammonium (TEA).

The resting membrane potential of a neuron is maintained by the Na+/K+-ATPase, which pumps 3 Na+ ions in and 2 K+ ions out.

Ligand-gated ion channels open below the threshold in a neuron.

Excitatory neurotransmitters: Glutamate, Aspartate Inhibitory neurotransmitters: GABA, Glycine

In an excitatory synapse, the membrane becomes less negative due to the inflow of sodium and/or calcium ions, resulting in an excitatory postsynaptic potential (EPSP).

In an IPSP, the membrane becomes more negative due to the outflow of potassium (K+) and the inflow of chloride (Cl-) ions.

+55mV

Positive membrane potential

There will be an outflow of sodium to decrease the membrane potential.

There will be an inflow of sodium.

There will be an inflow of sodium.

There will be an inflow of sodium.

-120 mV will have the strongest sodium inflow.

Net sodium flow will be 0.

The functional unit of skeletal muscle is the muscle fibre, which varies in length depending on the specific muscle.

A-alpha motoneurons have the following characteristics:

• Conduction velocity: 70-120 m/s
• Diameter: 15 μm
• Myelinated axons
• Associated with glial cells, specifically Schwann cells.

A motor unit consists of a motoneuron and all the muscle fibres it innervates. Each muscle fibre is innervated by only one motoneuron, while one motoneuron can innervate numerous muscle fibres (10-1000).

The innervation ratio is the number of muscle fibres innervated by a single motoneuron. It varies depending on the muscle type:

• Smaller muscles with finer movements (e.g., extraocular muscles) have a lower innervation ratio (3-10 muscle fibres).
• Larger muscles (e.g., quadriceps) have a higher innervation ratio, with one motoneuron innervating around 1000 muscle fibres.

The motor unit potential is the sum of action potentials from one motor unit.

No, a muscle fibre is only innervated by one motoneuron.

Voltage-gated calcium channels open when the action potential reaches the axon terminal, allowing calcium ions to flow into the terminal. This influx of calcium is crucial for the release of neurotransmitters from vesicles into the neuromuscular junction.

The action potential travels in a saltatory manner, jumping from one node of Ranvier to the next, which increases the conduction velocity of the action potential.

The release of neurotransmitters is triggered by the influx of calcium ions into the axon terminal, which occurs when voltage-gated calcium channels open in response to the action potential.

The electrochemical gradient causes calcium ions to flow into the axon terminal because the concentration of calcium is lower inside the terminal compared to the extracellular space, facilitating neurotransmitter release.

Acetylcholine is the neurotransmitter that binds to muscle type nicotinic acetylcholine receptors, which are ligand-gated ion channels. This binding opens sodium channels, allowing sodium to flow into the muscle cell, leading to depolarization.

The resting membrane potential of skeletal muscle is normally -90 mV.

The sodium-potassium-ATPase pump maintains the resting membrane potential by pumping out 3 Na+ ions and bringing in 2 K+ ions, which helps keep the inside of the cell more negative compared to the outside.

During depolarization, the membrane potential becomes less negative, and if the end plate potential reaches the threshold, voltage-gated sodium channels open, causing a rapid influx of sodium and the generation of an action potential.

Hyperpolarization occurs when the membrane potential becomes more negative than the resting membrane potential, following repolarization after an action potential.

Sarcoplasmic reticulum

The main function of the sarcoplasmic reticulum is to store and release calcium ions (Ca++) which are essential for muscle contraction.

DHP receptors are situated in the wall of the T-tubule. Their function is to activate ryanodine receptors.

Ryanodine receptors are located in the wall of the terminal cisternae. Their function is to release calcium.

The space inside the T-tubule is extracellular.

The calcium source for muscle contraction in skeletal muscle is intracellular, coming from the sarcoplasmic reticulum, which is inside the cell.

One molecule of troponin C can bind to 4 calcium ions.

The optimal length of a sarcomere to exert the maximal contraction force is between 2-2.2 micrometers (um).

The thin filaments in a sarcomere consist of:

• Actin
• Dystrophin
• Nebulin
• Tropomyosin
• Troponin I, Troponin C, Troponin T

Titin connects the Z-line to the myosin and back, anchoring the myosin to the Z-line, and is as long as the sarcomere itself.

The A-band is as long as the myosin itself and contains both thick and thin filaments.

The H-band is the length between the two actin molecules and contains only thick filaments.

The I-band extends from the end of one myosin to the next and contains only thin filaments.

Yes, DHP receptors are present in the heart.

Yes, ryanodine receptors are present in the heart.

Nebulin is as long as the actin filament and functions to support it.

The H-band and I-band get shorter during contraction.

During relaxation, there are no calcium signals, and ATP is needed to relax the muscle.

The calcium-ATPase pumps calcium back from the myoplasm to the sarcoplasmic reticulum during relaxation.

The troponin-tropomyosin complex occupies the myosin binding site on the actin filament during relaxation.

The troponin-tropomyosin complex consists of Tropomyosin, Troponin I (inhibits), Troponin C (binds to calcium), and Troponin T.

Both ATP and calcium are required for muscle activation during contraction.

When troponin C binds to calcium, it changes conformation, which also alters the conformation of the troponin-tropomyosin complex.

During muscle contraction, the angle between the myosin head and the myosin neck is 45°, while during relaxation it is 90°.

The myosin head binds to the actin site and tilts from 90° to 45°, allowing it to slide towards the Z-line and bind to the next actin, facilitating contraction.

The action potential reaches the axon terminal, opening voltage-gated calcium channels, leading to calcium inflow, neurotransmitter release (acetylcholine), and subsequent muscle cell depolarization and contraction.

DHP receptors in the T-tubules are triggered by the action potential, which then activates ryanodine receptors to release calcium from the sarcoplasmic reticulum into the sarcoplasm, initiating contraction.

The sliding filament mechanism occurs when the angle between the myosin head and neck changes, allowing myosin to bind to actin and slide, resulting in muscle contraction.

The amplitude of contraction is higher in smooth muscle, as seen in the uterus's ability to contract back after childbirth.

Muscle fatigue is a reversible decrease in the ability of skeletal muscle to exert force in response to physical activity. Its significance is to protect the body from complete or final depletion.

The types of muscle fatigue are:

1. Peripheral: Involves motoneurons and/or muscle fibers.
   • Transmissional: Lack of acetylcholine.
   • Contractional: Lack of energy sources and ions.
2. Central: Involves the CNS, mainly caused by hypoglycemia.
3. Mental (psychic): Involves factors like motivation, tolerance, attention, and focus.

The causes of peripheral fatigue include:

• Lactic acid formation leading to decreased pH
• Hypoxia
• Hypoglycemia
• Hyperthermia
• Dehydration

The order in which muscle uses energy sources is:

1. ATP
2. Phosphocreatine
3. Muscle glycogen
4. Liver glycogen

When there is no ATP, the muscle cannot contract or relax, leading to a condition known as 'Rigor Mortis', where the muscle becomes stiff.

Type I-A muscle fibers are red fibers caused by myoglobin, are slow-twitch, utilize aerobic glycolysis, show muscle fatigue later, are antigravitational muscles, have lots of mitochondria, and are typically used by marathon runners.

Type II-B muscle fibers are white fibers caused by glycogen, are fast-twitch, utilize anaerobic glycolysis, show muscle fatigue early, produce more lactate, and are typically used by 100m sprinters and weightlifters.

Regular muscle workouts do not increase the number of muscle fibers; instead, they lead to an increase in size known as hypertrophy.

The effects of training on muscle include:

1. Hypertrophy (bigger, stronger muscles)
2. Increased O2 uptake
3. Increased function and number of mitochondria
4. Increased aerobic enzyme capacity (from low intensity long training)
5. Increased anaerobic enzyme capacity (from high intensity interval training)
6. Increased lactate tolerance

Muscle strain is caused by microtrauma, which leads to sterile inflammation in the muscle.

EMG stands for electrical myography and it records the electrical activity of skeletal muscle.

The differences between surface and deep electrodes in EMG are:

The transducer converts the mechanical signal into an electrical signal.

The amplifier increases the amplitude of the electrical signal.

The filter removes parts of the noise; for example, to examine signals between 0.5Hz and 50Hz, a 0.5Hz high pass filter and a 50Hz low pass filter are used.

The minimum stimulus threshold is the single pulse with the lowest intensity that can induce a single twitch.

The maximal recruitment threshold is the stimulus intensity above which the amplitude of the contraction force stops increasing.

If a second action potential arrives before the muscle is fully relaxed, the force of the next contraction will be greater, a phenomenon known as summation or superposition.

When the stimulus frequency is increased and the muscle does not fully relax, the individual twitches will fuse into a single sustained contraction. If the twitches are still recognizable, it is called incomplete tetanus; if they fuse completely, it is called complete tetanus.

Myasthenia gravis is a chronic autoimmune neuromuscular disease that causes weakness in the skeletal muscles due to the production of antibodies against the nicotinic acetylcholine receptors (N-Ach-R) at the neuromuscular junction.

Malignant hyperthermia is caused by a mutation of the ryanodine receptors, leading to a severe reaction to certain anesthetic drugs. This reaction causes muscle activation and an increase in body temperature (hyperthermia), making temperature monitoring during surgery crucial.

The main treatment for malignant hyperthermia is the administration of dantrolene. Anesthesiologists give this drug immediately if malignant hyperthermia is suspected, stop the anesthetic, and the surgeon ends the surgery as soon as possible.

In neurogenic lesions, there is spontaneous activation of the muscle even when the patient is asked to relax, resulting in EMG signals. The motor unit potential is larger than normal, and there is no complete interference.

1. Resting phase: Myosin heads are not bound to actin (bound to ATP).
2. Depolarization: Action potential causes Ca2+ inflow, leading to depolarization.
3. Activation: Ca2+ binds to calmodulin, activating myosin light chain kinase, which phosphorylates myosin head.
4. Contraction: Phosphorylated myosin binds to actin, forming cross bridges, leading to sliding filament mechanism.
5. Maintaining phase: Unique to smooth muscle, uses a few ATP molecules.
6. Repolarization: ADP dissociates, Ca2+ levels normalize via Ca2+ pump and Na+/Ca2+ exchange.
7. Relaxation: Ca2+ decreases, myosin head detaches from actin, returns to 90°, binds new ATP.

• Tonic contraction: Long action potential with plateau phase, resulting in long-lasting contraction.
• Phasic contraction: Short-lasting, rhythmic contractions.

Ca2+ is sourced both intracellularly and extracellularly during smooth muscle contraction.

Smooth muscles are innervated by the autonomic nervous system, which is involuntary.

The resting membrane potential of smooth muscle ranges from -40 mV to -70 mV, which is considered unstable.

The duration of action potential in smooth muscle is longer compared to that in skeletal muscle, lasting approximately 25 times longer.

• Ligand gated Ca2+ channels
• K+ channels
• Voltage gated Ca2+ channels

Dens plaque

ATP

Activate MCL (myosin light chain) kinase

Yes, both muscles are working simultaneously.

• Increased oxygen uptake capacity
• Increased glucose uptake capacity
• Increased number and function of mitochondria
• Increased aerobic capacity
• Increased anaerobic glycolysis
• Increased lactate tolerance

• Troponin I inhibits the binding of actin and myosin
• Troponin C binds to calcium

Intracellular

Yes

2-2.2 um

The titin is as long as the sarcomere.

The nebulin is as long as the actin.

Both thick and thin filaments.

Thin filaments.

Thick filaments.

Curare is a non-depolarisation muscle relaxer; it doesn't change the membrane potential, it only inhibits the nicotinic Ach receptors.

Reversible

Direct: stimulate the muscle directly; Indirect: stimulate the nerve that stimulates the muscle.

There will be a contraction only when stimulated directly, as curare inhibits the receptors on the muscle membrane for indirect stimulation.

Curare inhibits the nicotinic acetylcholine (Ach) receptors on the muscle during both direct and indirect stimulation.

When the maximal threshold is reached, the maximal recruitment of muscle fibers is also reached, and the amplitude of the contraction cannot increase further.

The equipment used includes:

1. Stimulator (placed over the nerve)
2. Ground electrode
3. Electrode pair (2x)
4. EMG electrode
5. AD-setup

The grip force decreases due to muscle fatigue.

Factors that can influence muscle fatigue include:

• Nutrition
• Drug
• Sleep
• Physical state
• Mentality

During exercise, the systolic pressure primarily increases as more blood needs to be pumped out of the heart.

All living cells have membrane potential, but only excitable cells like skeletal, neural, and cardiac cells can generate action potential.

About 60% of the body weight of an adult human is fluid.

The two main types of body fluids are intracellular fluid (2/3 of body water) and extracellular fluid (1/3 of body water).

The extracellular fluid contains a large amount of sodium, chloride, bicarbonate, and nutrients such as oxygen, glucose, fatty acids, and amino acids.

The intracellular fluid contains a large amount of potassium, magnesium, and phosphate ions.

The total body water (TBW) of an average man weighing 70kg is 42kg.

The normal concentration range for sodium ions (Na+) in extracellular fluid is 135-152 mmol/L.

The normal concentration range for potassium ions (K+) in extracellular fluid is 3.8-5.2 mmol/L.

Fluid volumes can be measured using different dilution methods.

Total body water can be measured using heavy water (D₂O), tritium oxide (T₂O), or antipyrine. These substances are injected into the body, spread throughout body fluids, and their concentration is measured through a blood test after a certain period.

Extracellular fluid can be measured using the inulin dilution method or Mannitol. Inulin can enter interstitial and intravascular fluids but not intracellular fluid, allowing for the measurement of only extracellular fluid.

Hypernatremia refers to too high concentrations of sodium in the extracellular space, while hyponatremia refers to too low concentrations of sodium in the extracellular space.

Hyperkalaemia is a condition where potassium concentration in the extracellular space is higher than normal values. It can cause irregular heart rhythm or even stop the heart.

Hypokalaemia refers to too low levels of potassium in the extracellular space. It is dangerous because it can lead to arrhythmias.

The concentration of calcium (Ca2+) is higher in the intracellular space.

Hypomagnesia means too little magnesium in the extracellular space, which can cause an irregular heart rate.

The dominant ion in the extracellular space is sodium (Na+), while the dominant ion in the intracellular space is potassium (K+).

Plasma volume = blood volume * (1 – Htc)

Blood plasma consists of more than 90% water, along with inorganic and organic elements.

Blood serum is the blood plasma without the fibrinogen.

• Maintain colloid osmotic/oncotic pressure
• Function as buffers for blood pH regulation (normal 7.35-7.45)
• Maintain blood viscosity (4-6)
• Transport substances (e.g., iron by transferrin, hormones, and ions by albumin)
• Storage
• Humoral immune function (immunoglobulins)
• Hemostasis (blood coagulation/clotting)
• Participate in metabolic processes

• Females: 3.8-5.3 million / µl
• Males: 4.3-6 million / µl

Hypoxia, or lack of oxygen, stimulates the kidney to produce erythropoietin (EPO).

The lifespan of erythrocytes (RBCs) is 100-120 days.

• Low RBC count: Anemia (due to deficiencies in iron, vitamin, erythropoietin, or renal failure)
• High RBC count: Erythrocytosis (polycythemia) due to dehydration or polycythemia vera

The materials used include:

• Bürker's chamber
• Hayem's solution
• Mixing pipette
• Coverslip
• Microscope
• Capillary blood sample

The reticulocyte count is determined using the stain Brilliant cresyl blue.

The ratio of reticulocytes to mature RBCs reflects the activity of erythropoiesis.

The size in diameter of erythrocytes (RBCs) is 7-8 µm.

RBCs are released from the red bone marrow as reticulocytes, which are immature red blood cells.

RBC count = average number of RBCs × volume of square × dilution. For example, if the average number of RBCs is 10, the calculation would be: RBC count = 10 x 4000 x 100 = 4,000,000.

1. Stain a glass slide with brilliant cresyl blue staining and let it dry for a few minutes.
2. Place a small drop of blood on top of a coverslip and turn it upside down onto the stained coverslip.
3. After a few minutes, apply one drop of immersion oil on top of the coverslip.
4. Evaluate the preparation under the microscope using the immersion lens (100x) and count all the RBCs in one view field, looking for reticulocytes using the meander pattern.

The normal range of reticulocytes is 0.7-1.5% of the total RBCs.

Low reticulocyte counts can be caused by decreased erythropoiesis. High reticulocyte counts may indicate an increased rate of RBC production in the bone marrow, a compensatory process, or a sign of bone marrow tumors producing excess RBCs.

Materials needed: 0.9% NaCl solution, glass slide, coverslip, microscope with an eyepiece graticule, immersion oil, calibration slide, and capillary venous sample.

Steps:

1. Calibrate the scale of the eyepiece graticule to determine the length of one unit.
2. Dilute one drop of blood with a larger drop of physiological NaCl solution on the glass slide and cover it with a coverslip.
3. Place one drop of immersion oil on the coverslip.
4. Measure the diameter of 100-200 RBCs under the microscope.
5. Calculate the mean diameter by averaging the measured diameters of the RBCs.

The Price Jones curve illustrates the distribution of RBC sizes, showing a symmetric Gaussian curve with a peak at the mean diameter of normal RBCs (7-8 µm). It helps in understanding variations in RBC sizes, such as microcytosis (smaller RBCs) and macrocytosis (larger RBCs).

During RBC degradation, hemoglobin is released when the cell membrane ruptures. It is then phagocytized by tissue macrophages, where it splits into heme and globin. The heme is further processed to release free iron, which is recycled, while the globin is broken down into amino acids.

Indirect bilirubin is water insoluble and is transported in the blood by strongly binding to albumin, a water-soluble plasma protein, which allows it to circulate throughout the bloodstream.

The degradation of red blood cells primarily occurs in the reticuloendothelial system of the spleen, where macrophages phagocytize the aged RBCs and process hemoglobin.

Indirect bilirubin is absorbed through the hepatic cell membrane in the liver, where it is converted into conjugated bilirubin (active bilirubin), which is then exported to the bile canaliculi and into the intestines.

The initial step is the conversion of fragile red blood cells into heme by the reticuloendothelial system.

In the liver, unconjugated bilirubin is converted into conjugated bilirubin.

The two pathways are:

1. Some urobilinogen moves to the kidneys.
2. Urobilinogen undergoes bacterial action and is converted into stercobilinogen, which is then oxidized into stercobilin in the intestinal contents.

In the kidneys, urobilinogen can be oxidized into urobilin and then excreted in the urine.

Hematocrit is the volume proportion of the formed elements in the blood, specifically the ratio of the volume of blood cells to the volume of whole blood.

Hematocrit levels depend on several factors including:

• RBC count (99%)
• Iron
• Folic acid
• Vitamin B12
• Intrinsic factor
• Kidney function
• EPO (Erythropoietin)
• Altitude
• Hypoxia
• WBC count
• Platelet count

Normal values of hematocrit (Htc) are:

• Males: 0.41 - 0.52 / μl = 41-52%
• Females: 0.37 – 0.47 / μl = 37-47%

The cells contributing to the hematocrit are:

• Red blood cells: 99%
• White blood cells: 0.1-0.2%
• Thrombocytes: 0.8-0.9%

To determine hematocrit:

1. Fill a heparin-coated capillary with blood from a punctured fingertip until 4/5 full.
2. Seal the other end with plasticine.
3. Centrifuge the capillary for 5 minutes at 10,000 RPM.
4. Place the capillary on the hematocrit chart with the bottom of the blood column on the 'O' line and move horizontally until the top of the plasma column intersects the '100' line. The intersection point determines the hematocrit value.

MCV stands for mean corpuscular volume and indicates the average size of one red blood cell.

The normal range for MCV is 82-92 fl. Macrocytosis indicates RBC size higher than 94 fl, while microcytosis indicates RBC size lower than 80 fl.

MCH stands for mean corpuscular hemoglobin and measures the average amount of hemoglobin present in a single red blood cell.

The normal value for MCH is between 28-36 pg. Higher values indicate macrocytic anemia, while lower values indicate microcytic anemia.

Microcytic anemia can be caused by iron deficiency.

Macrocytic anemia can be caused by:

• Vitamin B12 deficiency (involved in DNA synthesis)
• Intrinsic factor deficiency (produced by parietal cells, leads to vitamin B12 deficiency)
• Folic acid deficiency (needed for DNA synthesis for erythropoietin cells).

MCHC stands for mean corpuscular hemoglobin concentration and indicates the average concentration of hemoglobin in 1L of red blood cells.

The normal values for MCHC are 310-360 g/L (adults). A lack of hemoglobin in the blood may indicate anemia.

The mnemonic is 'Never Let Monkeys Eat Bananas'.

Neutrophils are the largest fraction of white blood cells and are primarily involved in fighting bacterial infections. A high number of young neutrophils (left shift) can indicate a bacterial infection.

T-lymphocytes are involved in the cellular immune response, fighting against other cells, while B-lymphocytes produce antibodies (immunoglobulins) for the humoral immune response.

Monocytes are the largest white blood cells and can leave the bloodstream to become macrophages in tissues, where they are involved in antigen presentation.

Eosinophils fight against parasitic infections and allergic reactions, and they also regulate basophil granulocytes.

Basophil granulocytes produce histamine and their numbers can increase in response to exogenic parasite infections or allergies.

The blood smear film is stained using diluted May-Grunwald staining for 3 minutes, followed by a mixture of deionised water and May-Grunwald solution for 1-3 minutes, and finally with deionised water and Giemsa solution for 10-15 minutes.

Türk's solution is used for white blood cell counting, and the rate of dilution of the blood sample is 1:10.

The large square of the Bürker's chamber is used for leukocyte count.

WBC count is calculated using the formula:

WBC count = Average WBCs x volume of square x dilution

For this case: WBC count = 4 x 250 x 10 = 10,000.

The lymphocyte count is calculated using the formula:

Lymphocytes = WBC count / 100 x percentage of the cell type

Thus, Lymphocytes = 10,000 / 100 x 40% = 4000 / µl.

Thrombocytes, also known as platelets, are crucial for the formation of the thrombocyte/platelet plug. They lack nuclei and cannot reproduce, but contain actin, myosin, and the contractile protein thrombosthenin.

The normal range of thrombocytes/platelets is 150,000 – 400,000 per μl.

The formation of thrombocytes in the bone marrow is stimulated by thrombopoietin, which is produced in the kidney.

Too high levels of platelets are called thrombocytosis, while too low levels are referred to as thrombocytopenia.

The materials used include a Bürker's chamber, coverslip, microscope, pipette, test tube, and Rees-Ecker's solution.

1. Pipette 0.9 ml of Rees-Ecker's solution into a test tube.
2. Add 0.1 ml of blood and mix.
3. Incubate the test tube for 1-2 hours.
4. Observe the thrombocyte rich plasma as a whitish layer on the surface.
5. Sample this layer and place it on both sides of the Bürker's chamber.
6. Count the platelets in over ten of the large rectangles using the L-law under the microscope.

Platelet count is calculated using the formula: Platelet count = average number of platelets x volume of rectangle x dilution. For example, if the average number of platelets is 20, the platelet count would be 20 × 1000 × 10 = 200,000.

The first step is vasoconstriction, which involves the contraction of smooth muscle in the wall of the broken vessel. This decreases blood flow by shrinking the lumen, facilitating plug formation and reducing blood loss.

Key vasoconstrictors include:

• Serotonin
• ATP
• Prostaglandin-F2 (PgF2)
• Adrenalin (epinephrine) via alpha-1 receptors
• Noradrenalin (norepinephrine) via alpha-1 receptors
• Thromboxane A2
• Endothelin (strongest one)
• Hormones such as angiotensin II and ADH (antidiuretic hormone/vasopressin)

During thrombocyte plug formation, when the endothelium is damaged, platelets bind to collagen in the surrounding tissue, activating them. Activated platelets release granule contents like serotonin, ADP, and thromboxane A2, which stimulate further vasoconstriction and activate nearby platelets, leading to the formation of a platelet plug.

Prolonged bleeding time can be caused by malfunction of the thrombocytes or thrombocytopenia (low levels of thrombocytes).

A bleeding time lower than normal is generally considered not pathological, meaning it is within acceptable limits and not a cause for concern.

Bleeding time increases to longer than 5 minutes.

The intrinsic pathway starts with the activation of prekallikrein to kallikrein, which activates factor XII, leading to a cascade that ultimately activates factor X, contributing to the formation of the prothrombin complex.

The intrinsic tenase complex consists of IXa, VIIIa, Ca2+, and phospholipids.

The prothrombin complex includes Xa, Va, Ca2+, and phospholipids, which are essential for converting prothrombin (factor II) into thrombin (active factor II).

The extrinsic pathway is initiated by tissue factor activating factor VII, which becomes VIla, leading to the activation of factor X.

The main difference is that the intrinsic pathway is activated in vitro without tissue factors, while the extrinsic pathway is activated in vivo by tissue factor.

The extrinsic tenase complex consists of tissue factor, VIIa, Ca2+, and phospholipid.

The four substances are:

1. Sodium oxalate
2. Sodium acetate
3. Sodium citrate
4. EDTA

The clotting factors that do not have protease activity are:

• XIIa
• Va
• VIIa
• IV (Ca2+)
• Ia (fibrin)

Thrombin (factor IIa) has several functions:

• Activates thrombocytes
• Converts fibrinogen (factor I) to fibrin
• Activates clotting factors V, VIII, XI, and XIII
• Together with thrombomodulin, it activates protein C.

In the case of liver failure, the clotting time increases because the liver produces plasma proteins, and most clotting factors are plasma proteins.

The vitamin-K dependent clotting factors produced in the liver are:

• Factor II (prothrombin)
• Factor VII
• Factor IX
• Factor X

In case of vitamin-K deficiency:

• Prothrombin time – increased
• INR – increased
• Prothrombin (Quick) index - decreased

When vitamin-K antagonists such as Coumarin or Warfarin are administered:

• Prothrombin time – increased
• INR – increased
• Prothrombin (Quick) index - decreased

The vitamin-K dependent anticoagulant factors are:

• Protein C
• Protein S

The normal prothrombin time range is 13-22 seconds.

Intrinsic pathway activation can be measured by prothrombin time. The procedure involves:

1. Pipetting 100µl sample plasma on a watch glass in a 37 °C water bath.
2. After some minutes, adding 200µl thromboplastin-Ca2+ reagent into the plasma sample and starting the stopwatch.
3. Stopping the stopwatch when the first fibrin fibre appears.
4. Repeating the steps with standard plasma and calculating the results.

The prothrombin index is calculated using the formula:

Prothrombin index (%) = (Prothrombin time of standard plasma / Prothrombin time of sample plasma) * 100%

The normal value of prothrombin index is 70-120%.

The normal value of INR (International Normalized Ratio) is 0.8-1.2. It is calculated using the formula:

INR = (PTsample / PTstandard)^ISI

A higher INR and lower Quick index indicate a prolonged clotting time, which increases the risk of bleeding.

The prothrombin index is calculated as follows:

Prothrombin index = (15/30) * 100% = 50%

• Prothrombin time: Increase
• INR: Increase
• Prothrombin (Quick) index: Decrease

This occurs because vitamin K, a fat-soluble vitamin, is not absorbed, affecting vitamin K dependent factors (II, VII, IX, and X), leading to longer clotting times.

• The clotting time will be longer.
• Prothrombin time: Increase
• INR: Increase
• Prothrombin (Quick) index: Decrease

This is due to the anticoagulant effect of Warfarin or Coumarin, which inhibits vitamin K dependent factors.

In case of hypercalcemia, there will be no change in the clotting time. While calcium is necessary for clotting, excess calcium does not accelerate the process.

Hemoglobin primarily functions as an oxygen transporter in the blood and also aids in carbon dioxide transport. Additionally, it acts as a buffer for pH due to its high concentration and the presence of histidine molecules.

A right shift in the O2-hemoglobin dissociation curve indicates that more oxygen pressure is needed to achieve the same saturation, reflecting a decreased affinity of hemoglobin for oxygen. This shift can occur due to hypercapnia, acidosis, hyperthermia, and increased concentration of diphosphoglycerate (2,3-DPG), often during exercise.

A left shift in the O2-hemoglobin dissociation curve is caused by factors such as hypocapnia, alkalosis, hypothermia, and decreased concentration of diphosphoglycerate (2,3-DPG). This shift indicates an increased affinity of hemoglobin for oxygen.

The normal hemoglobin concentration range for females is 120-160 g/L.

The normal hemoglobin concentration range for males is 140-180 g/L.

The O2-Hb curve shifts to the right, indicating acidosis.

The O2-Hb curve shifts to the left.

The O2-Hb curve shifts to the left.

The O2-Hb curve shifts to the right.

Drabkin's method involves osmotic hemolysis of RBCs followed by the transformation of Hb molecules to cyan-hemoglobin, which is stable and can be measured photometrically at 540 nm.

A hemoglobinnometer compares the absorption of light through a hemolysed blood sample to that of a calibrated prism, using a 546 nm optical filter to measure the sample's color against a standard color, providing results in g/100 ml or as a percentage of the mean value.

The effective filtration pressure is calculated as follows: 30 mmHg - 25 mmHg - 5 mmHg + 5 mmHg = 5 mmHg.

When the effective filtration pressure is positive, water moves from the capillaries to the interstitium.

Factors that increase filtration include:

1. High blood pressure
2. Low protein intake
3. Histamine (increases permeability of vessels)
4. Low hydrostatic pressure of interstitial fluid
5. Thrombosis (blood clot in vein)
6. Glycoprotein outside the vessel
7. Liver failure

Factors that decrease filtration include:

1. Low blood pressure
2. Blood loss
3. Dehydration
4. Hyperproteinaemia
5. High hydrostatic pressure of interstitial fluid
6. Increase in histaminase (degrades histamine)
7. Massage (pressure)

An increase in glycoprotein in the interstitial space increases filtration because it raises the colloid osmotic pressure.

In liver failure, filtration increases because the liver cannot produce plasma proteins, leading to a decrease in colloid osmotic pressure of the plasma and a decrease in the inward force of the capillary.

The ABO blood group system consists of four main blood types: A, B, AB, and O.

Type A blood contains anti-B antibodies in the plasma.

The immunoglobulin responsible for ABO blood type groups is IgM.

Type O blood contains neither type A nor B antigens on the RBCs, but both anti-A and anti-B antibodies in the blood plasma.

The alleles coding for the A and B antigens are codominant against the recessive O allele, which codes for an inactive variant of the enzyme that leaves the H antigen unchanged.

Type AB blood contains no antibodies in the blood plasma.

Blood type is determined by using test serums containing antibodies to detect the antigens present on the surface of red blood cells. The presence or absence of agglutination indicates the blood type:

• Type A: Agglutination with anti-A serum
• Type B: Agglutination with anti-B serum
• Type O: No agglutination with either serum
• Type AB: Agglutination with both anti-A and anti-B serums.

When anti-A antibodies are added to blood type A, agglutination occurs because type A blood contains A antigens on the surface of the red blood cells.

Adding anti-B antibodies to blood type B results in agglutination because blood type B contains B antigens on the surface of the red blood cells.

Agglutination indicates the presence of specific antigens on the red blood cells. It helps in identifying the blood type:

• Type A: Agglutination with anti-A
• Type B: Agglutination with anti-B
• Type AB: Agglutination with both
• Type O: No agglutination.

If agglutination is not detected in any reactions, it indicates that the subject has blood type O, as there are no A or B antigens present on the red blood cells.

If agglutination is detected in reaction C, the test is considered invalid and must be repeated to ensure accurate results.

The Rh blood group system is primarily characterized by the presence of the D-antigen, which is the most immunogenic and routinely tested antigen. Individuals with the D antigen are Rh positive, while those without it are Rh negative.

The presence of the D antigen can be determined using a hemagglutination test, where a blood sample is mixed with anti-D serum. If agglutination occurs, the blood sample is Rh(D) positive.

The anti-D antibody is classified as IgG.

Rh- blood type can develop anti-D antibodies if it comes into contact with Rh+ blood, leading to the formation of these antibodies.

The universal blood donor group is O-, and the universal blood receiver group is AB+.

The Bombay blood group is defined by the lack of H-antigen, A-antigen, and B-antigen on the surface of RBCs. Individuals in this group have anti-A, anti-B, and anti-H antibodies in their blood plasma.

The patient's blood group could be O-.

The possible blood types of the patient are B+, B-, AB+, and AB-.

The D-antigen is not ubiquitous; in Rh-negative blood, it is not certain that there are no anti-D antibodies in the blood plasma, hence we cannot exclude that Rh is negative.

The possible blood types are A+, A-, AB+, and AB-.

The ESR is the rate at which red blood cells (RBCs) settle down in a tube for one hour, measured in mm/hour.

Biological factors include:

1. Shape and size of RBCs
2. RBC count
3. Viscosity of the plasma
4. Albumin/globulin-fibrinogen ratio of plasma (most important factor)

Technical factors include:

1. High temperature (↑ ESR)
2. Tilted position of the tube (↑ ESR)
3. Underdilution (↑ ESR) / overdilution (↓ ESR) of the blood sample

A higher ratio of albumin to globulin and fibrinogens results in a lower ESR, while a lower ratio leads to a higher ESR. This is because RBCs that stick together (rouleaux) settle faster than individual RBCs, and the negative charge on RBC surfaces prevents rouleaux formation, which is reduced by globulins and fibrinogens.

Factors that increase ESR include:

• ↑ Globulin level (e.g., infections, malignancies, tissue necrosis)
• ↑ Fibrinogen level (e.g., inflammation)
• ↓ Albumin level
• Pregnancy
• Menstruation
• Anemia
• Macrocytosis

Factors that decrease ESR include:

• Increased blood viscosity
• Polycythemia
• Microcytosis
• Abnormal RBCs (sickle cells)

Osmotic resistance of RBCs is the concentration of the most diluted NaCl solution which the RBCs do not hemolyse. It indicates how well RBCs can withstand osmotic pressure without bursting.

In hypertonic solutions, red blood cells shrink due to water loss, resulting in a crumpled appearance.

In hypotonic solutions, red blood cells take up extra water and swell. If the osmotic concentration is too low, the cell membrane may rupture, leading to hemolysis.

The normal osmotic resistance for red blood cells is between 0.46% and 0.42% NaCl solution.

By marking five glass slides with numbers 1-5 and adding different solutions: 1 – 3% NaCl, 2 – 0.9% NaCl, 3 – 0.4% NaCl, 4 - deionised water, 5 – 0.9% NaCl solution and diethyl ether. A drop of blood is added to each slide, covered with a cover slip, and examined under a microscope using the 100x objective with immersion oil.

Osmotic resistance decreases in spherocytosis and increases in iron deficiency and sickle cell disease.

RBCs will rupture earlier at higher osmotic resistance.

A centrifuge is used in hematocrit and the quantitative osmotic resistance of RBCs measurements.

The four compartments of a neuron are:

1. Dendrites (input)
2. Axon hillock (integration)
3. Axon (conductor)
4. Synapse (output)

In the node of Ranvier.

The different types of neurons based on their function are:

• Afferent (sensory) neurons
• Efferent (motor) neurons
• Interneurons (connects other neurons)
• Associative neurons (only in the CNS)