Lab Practical 1 - PNB 2275

Describe Basophils

Basophils are the least numerous type of leukocyte. They also have bi-lobed nuclei; what distinguishes them from eosinophils are their blue-violet granules.

What is beers law?

Beer's Law describes a linear relationship between concentration of a solute in the sample and the absorbance of light.

Besides polycythemia, name one more condition or disease state that can be detected/diagnosed using hematocrit, and describe how hematocrit would change and why.

Besides polycythemia, one more condition that can be detected using hematocrit is doping. At a normal level, the red blood cell level in a hematocrit is at about 40%. But with the action of doping, the hematocrit level is high. In other words, there is a higher percentage of red blood cells, making the ratio of red blood cells to total blood volume larger. This makes sense due to the fact that in blood doping a person, especially athletes, receive injections of EPO (erythropoietin) to stimulate excessive (higher than normal) production of red blood cells and also blood transfusions to again increase their red blood cell percentage.

What type of tissue is blood?

Blood is a type of connective tissue that is able to regenerate itself on a regular basis

What is blood responsible for?

Blood is responsible for transporting the gases, nutrients, and hormones our bodies need for normal functioning.

Describe the sympathetic system vs parasympathetic in relation to their main neurotransmitter release.

Both divisions have major and opposite effects on heart rate; the sympathetic through norepinephrine release and the parasympathetic through acetylcholine release.

Pre Lab 5

By end of lab, you will be able to: Name components of lymphatic system, and differentiate general functions of primary and secondary lymphoid organs. Indicate red and white pulp on a spleen slide. Differentiate between roles of B-cells and T-cells in immune response. Use Hemolytic Plaque Assay to demonstrate presence of antibody-producing plasma cells. Explain steps in E.L.I.S.A. Perform an experiment using E.L.I.S.A. technique, and interpret results of the experiment.

What is true at low partial pressures of oxygen? What happens as this increases?

Note that, at low partial pressures of oxygen, the curve has a shallow slope, indicating hemoglobin in a state of low oxygen affinity. As oxygen partial pressures increase, the curve becomes steeper, indicating an increasing affinity of hemoglobin for oxygen. The affinity remains high—a steep curve—until the percent binding of oxygen to hemoglobin levels off as we approach full saturation with oxygen. The curve is called a dissociation curve because of our interest in how the hemoglobin unloads, or dissociates from, oxygen under different conditions.

Describe an action potential in relation to ECG

Notice that the mechanical events of the cardiac cycle lag slightly behind the electrical signal, just as the contraction of a single cardiac muscle cell follows its action potential. However, an ECG is not the same as a single action potential. An action potential is one electrical event recorded from a single cell, often intracellularly; the ECG is an extracellular recording that represents the sum of multiple action potentials taking place in many heart muscle cells.

Describe Step 3: Measure amplitudes of R and S waves

Now let's estimate the area/amplitude of each of wave. We will consider the Q wave, R wave, and S wave separately. This is an easy step. We will determine how tall each wave is by counting how many squares there are, from the isoelectric line (shown in green) to the peak of the wave (shown in red). For the R wave in lead one, it is approximately 3.5 squares. Each square equals 1 mm, so the amplitude of R wave is 3.5 mm. For the S wave in the same lead, it is approximately 1 square going downward, so 1 mm in the other direction

Describe the flow of positive current moving from positive to negative

On the other hand, when positive current moving from positive to negative, it will create a negative deflection.

What is p50?

On the oxygen-hemoglobin dissociation curve, we can identify a point called the P50, which is the partial pressure of oxygen at which the hemoglobin is 50% saturated with oxygen. The P50 can be a useful reference point for comparisons.

Describe the tissue of a myocardial infarction

On the right, this tissue has suffered from myocardial infarction (also called a heart attack). This occurs when one of the arteries that supplies blood to the heart muscles becomes blocked. The blockage results in damaged tissue and a permanent loss of contraction of this portion of the heart muscle. It is very obvious that this slide has many purple-labeled cells - those are neutrophils. If you look carefully, you may see loss of cross-striation and that the nuclei are undergoing karyolysis. Dead myocytes lose their nuclei. The extensive neutrophilic infiltrate, along with loss of striation and nuclei suggests that this tissue may have been collected 2-3 days after the heart attack incident.

Describe Plasma, how much percent of the blood does it take up?

On top is a straw-colored liquid called plasma. It generally makes up about 55% of the blood. Plasma consists mostly of water, but also contains proteins and other dissolved solutes such as urea, salts, and organic nutrients.

The Q10 effect

One method used to decide whether a particular biological process is energy-dependent (e.g.; metabolism) or passive (e.g.; diffusion), is to calculate Q10 for the process. The following equation is used for this purpose. Where: t = temperature (°C), HR1 = heart rate at t1 and HR2 = heart rate at t2.

What can the direction of the vector indicate?

One of the most important properties of the triangular configuration is that we can make use of the multiple lead ECGs to calculate a vector that represents the average direction of current flow in the heart (mean electrical axis). The direction of the vector can indicate orientation of the heart as well as pattern of electrical excitation of the heart. This information has diagnostic significance. The simplest method of vectorial analysis of ECG makes use of recordings of any two leads of frontal plane (for example, Lead I and Lead III).

Where are pacemaker cells located in human hearts?

One thing that is probably not too obvious by mere inspection of the figures is that in the human heart, the pacemaker cells are located in the sino-atrial (or SA) node and atrioventricular (or AV) node

What is the angle of the vector recorded from your ECG? Is your calculated angle considered normal?

Our calculated angle of the vector recorded from our ECG was 71 degrees. Our angle is within 0 to 90 degrees, meaning it is within the normal range.

Describe Step 4: Calculate the overall QRS amplitude

Our next step for this lead is to subtract the heights of the negative going leads from the height of the positive going leads: So, the overall height of QRS complex = (Height of the R wave) - (Height of the Q wave) - (Height of the S wave). Since we have no Q wave in this example, this works out to: (Height of the R wave) - (Height of the S wave); 3.5 mm - 1 mm = 2.5 mm. We're not quite finished with this lead yet - we need to plot this number (2.5 mm) on the appropriate axis. Height of the R wave - Height of the Q wave - Height of the S wave (3.5 - 1 = 2.5 mm)

Refractory period

In this week's lab, we are also going to investigate the refractory period of cardiac muscle. Unlike action potentials generated in neurons and skeletal muscles, myocardial cells have a very long "plateau phase" before repolarization. You might want to ask why there is a prolonged sodium channel inactivation. The answer is that the calcium channels in the heart prevent the membrane potential from re-polarizing quickly. Why is this important? Due to the prolonged plateau-phase of the action potential, inactivation of Na channels is near-complete; the removal of inactivation gates from all Na+ channels on repolarization is somewhat delayed and therefore results in a longer refractory period.

Describe a indirect ELISA

Indirect ELISA involves having the secondary antibody conjugated to such a molecule. The secondary antibody is then used to bind to endogenously-produced antibody from blood serum.

Describe infectious mononucleosis

Infectious Mononucleosis is a widespread viral disease characterized by fever, sore throat, and fatigue. Infectious mononucleosis is most commonly caused by the Epstein-Barr Virus. Its histological phenotype is reactive or atypical lymphocytes, as you can see here.When the disease was first characterized, clinicians mis-identified those atypical lymphocytes as monocytes, and thus gave the disease the misleading name of mononucleosis. The reactive lymphocytes are larger than a typical lymphocyte, with abnormally-shaped nuclei. We cannot compare the size of the cells directly between these slides, but you can see the bright blue cytoplasm and should notice the unusual shape of the cells, which feature what is termed "cytoplasmic skirting" around the red blood cells.

What is isoproterenol?

Isoproterenol is a synthetic amine that is structurally related to epinephrine, acting as an agonist almost exclusively at beta receptors.

A lymph node is a...

It bears noting that, as it flows throughout the lymphatic system, lymph circulates through lymph nodes spread throughout the body (Fig. 4). A lymph node is an example of a secondary lymphoid organ.

Why is it necessary to add gelatin to the wells?

It is necessary to add gelatin to the wells during the ELISA process due to the fact that this gelatin covers the gaps between each antigen of which is exposing the PVC plastic. This ensures that the antibodies bind only to the antigens, not also the sticky plastic.

Prelab 2

Learning goals and objectives: Anatomy of the heart → Describe the major anatomical landmarks of the heart using a preserved sheep heart ECG and heart sound → Identify the major components of the ECG (P wave, QRS complex, T wave) → Calculate the mean QRS axis Histology of the cardiac tissue → Compare and contrast normal and pathological cardiovascular tissue

Pre Lab 4

Learning objectives: Introduction to spectrophotometry Calculation of sample concentration using Beer's Law Experimental tips for use of the spectrophotometer Oxygen-Hemoglobin dissociation curves Effects of different physiologic conditions on hemoglobin-oxygen binding

What is the lambda max?

Light wavelength is in units of nanometers and absorbance is measured in arbitrary units. Note that there are differences in absorbance at different wavelengths of light that are projected through the sample. The absorbance maximum (or lambda max) is the wavelength at which a particular substance maximally absorbs light.

Describe the shape of hemoglobin

Each hemoglobin molecule consists of four polypeptide chains called globins. Two of them are called alpha chains, and the other two are called beta chains. Each of these globin chains contains a ring-shaped nonprotein group called a heme group, with a divalent iron ion in the center. This iron ion allows for oxygen binding and transport in the blood. Since we have four rings, each hemoglobin molecule is capable of carrying 4 molecules of oxygen.

Describe Einthoven's triangle

Einthoven's triangle was proposed by a Dutch physiologist named Walter Einthoven at the beginning of the 20th century. He created a hypothetical triangle around the heart to describe the recorded electrical activity when electrodes are placed at the distal ends of a human body - normally both arms and the left leg as shown here (Fig. 1). The sides of the triangle are numbered to correspond with the three pairs of electrodes used for a recording, each pair of electrodes is called a lead.

Describe Eosinophils

Eosinophils have red or pink granules in their cytoplasm, and their nuclei are bi-lobed, with two lobes connected by a strand. It may help you to remember that Eos is the Greek goddess of the dawn, which brings a pink color to the eastern sky. Indeed, her name is related to the English word "east". Eosin stains these granules pink.

What will hemaggulation eventually lead to?

Eventually, hemagglutination will cause hemolysis, which is the rupture of the red blood cells. Cell contents and fragments will then get released into the blood, and this will cause mass activation of the immune system, which can lead to shock, kidney failure, and ultimately death.

Define hemoglobin and describe its function

Every red blood cell is filled with millions of molecules of a red-pigmented protein called hemoglobin. This protein transports oxygen and carbon dioxide and gives the red blood cells a characteristic bright red color.

What factors ca impact cardiac function?

Factors tested include: Temperature, ionic concentration, parasympathetic and sympathetic innervation, mechanical stretch, electrical blockage.

Describe atherosclerosis

Fatty plaque and cholesterol buildup inside arteries You probably noticed that the one on the left seems to have a large deposition of lipid or other debris on the inside. This condition is called atherosclerosis and is quite dangerous, and may contribute to many pathological conditions.

Describe Step 8: Find the mean QRS axis

Finally, draw a line from the zero point in the middle to where the two dashed lines you just drew intersect. This orange line is our mean QRS axis. You can see that what we measured in Lead I and Lead II are projections of the actual net electrical signals to these two axes. We can then measure the angle of this line starting with zero at the positive end of Lead I and going clockwise around. In this case, the angle is around 85 degrees or so.

where does the right lymphatic duct merge?

Lymphatic capillaries ultimately merge into larger lymph vessels and then into ducts: → The right lymphatic duct and the thoracic duct (Fig. 3).

Describe lymphocytes and monocytes

Lymphocytes have large, round nuclei, while monocyte nuclei are kidney shaped or C-shaped.

Describe Step 2 of an indirect ELISA

In Step 2 of an indirect ELISA, a primary antibody that is specific for the antigen of interest is added to the wells. The primary antibody is so called because it binds directly to the antigen of interest.In clinical tests, patient blood serum is added to the wells. If the patient has been exposed to an antigen, and has antibodies to that antigen in the serum, the patient's antibodies will bind specifically to the antigen coated on the wells.

Describe Step 3 of an indirect ELISA

In Step 3 of an indirect ELISA, a secondary antibody is added to the wells. The secondary antibody recognizes and binds to the Fc regions of the primary antibodies, which in the case of a clinical ELISA will be human patient antibodies. This secondary antibody is linked to an enzyme. The secondary antibody is so called because it does not bind directly to an antigen but to the primary antibody.

Describe Step 4 of an indirect ELISA

In Step 4 of an indirect ELISA, chromogenic (color-creating) substrate is added to the wells. In positive wells—that is, wells where the antigen has been bound by a primary antibody—the enzyme on the secondary antibody will convert the substrate to a colored end product. In negative wells—wells where no primary antibody bound—no color will develop.

Prelab 1

Overview: Part 1 - Formed Elements of Blood - Overview of components of blood and their general functions in maintaining homeostasis - Histology of formed elements of normal blood - Histology of formed elements in blood disorders Part 2 - Blood Typing - Physiologic basis for blood typing - Importance of blood types in transfusion - Technique and analysis of blood typing results - Demonstration of lab technique Part 3 - Hemoglobinometer and Hematocrit - Differentiate the two techniques - Interpretation of results - Make predictions for various pathological conditions - Demonstration of lab techniques

PQRST waves

P Wave: Atrial depolarization QRS Complex: Ventricular depolarization (contains atrial repolarization) T Wave: Ventricular repolarization

Where are the electrodes placed?

Pin the positive electrode on the right shoulder Pin the round electrode on the left thigh. → These electrodes allow you to view the ECG of the heart. It is important that you squirt the heart frequently with frog ringer's solutions. Negative electrode is on heart hook

If individuals were suffering from polycythemia, how would this affect their hematocrit?

Polycythemia is a disease that causes an elevated proportion of red blood cells, either by increasing the number of red blood cells or by decreasing blood plasma volume. On the other hand, the hematocrit is a technique used to assess the amount of red blood cells. It depicts the fraction of whole blood volume of which consists of red blood cells. Therefore, taking these two pieces of information into account, if an individual were suffering from polycythemia, a persons hematocrit would increase as the disease causes an increase in RBC and therefore a higher fraction of the blood consisting of red blood cells.

How does poor rinsing affect the results?

Poor rinsing results in the existence of free primary antibodies within the wells. These antibodies should have been removed as they can bind to the secondary antibodies and cause inaccurate positive results. Therefore, effective rinsing is extremely important.

What will be used to measure the mechanical and electrical signals of the frog heart?

Power lab and the force transducer will be used to measure the mechanical and electrical signals of the frog heart.

Define primary lymphoid organs and give examples

Primary lymphoid organs are sites where the cells of the immune system are generated and mature: → These include the bone marrow—where B-cells mature--and the thymus, where T-cells mature.

Describe the three types of cardiac tissues

Normal cardiac tissue -Note branching, striated fibers; centrally located nuclei, and intercalated discs. Myocardial infarction -When blood supply (and oxygen) to myocardium is interrupted, myocardial cells quickly die. The destruction of cell membranes results in release of cell contents into systemic circulation which can be detected by elevated levels of K+ and serum enzymes. Note destruction of myocardial tissue in this slide. Atherosclerosis -This slide shows a mostly occluded coronary artery. Note decreased size of arterial lumen due to accumulation of plaque (deposits of fat, fibrin, cellular debris, and calcium) on interior wall.

Describe cooperativity

The multiple subunits of hemoglobin cooperate in such a way that once one subunit binds to oxygen, more subunits are converted to the relaxed, oxygen-receptive state. Thus, the more oxygen that binds, the more receptive the hemoglobin becomes to binding even more oxygen molecules. This process, which puts the hemoglobin into progressively more high-affinity states, is called cooperativity. Cooperativity accounts for efficient oxygen loading onto hemoglobin at the lungs, where oxygen levels are high, as well as efficient unloading of oxygen from hemoglobin at the tissues, where oxygen levels are lower.

Describe the nerve bundle

The nerve bundle does not have any openings. It consists of many nerve fibers.

Describe the difference in calcium in the skeletal muscle vs the cardiac muscle

Recall that in skeletal muscle, calcium enters the cytosol exclusively through the ryanodine receptor on the sarcoplasmic reticulum, or SR. The sarcoplasmic reticulum surrounds the myofibrils and holds a reserve of the calcium ions needed to cause a muscle contraction in response to an action potential propagating through the T tubules. In cardiac muscle, the situation is largely the same, with one significant exception: calcium enters the cytoplasm through L-type calcium channels in the plasma membrane. This calcium also binds to and activates ryanodine receptors on the myocardial SR, in a process known as calcium-induced calcium release.

Describe the normal potassium ion concentrations

Recall that potassium concentrations inside the cell are relatively higher than those on the outside, creating a high inward-to-outward concentration gradient. This allows spontaneous potassium efflux from the cell and contributes to maintenance of a negative resting membrane potential, as positive charge is leaving the cell.

Describe the red pulp

Red pulp, highlighted here, is very vascular—that is, filled with blood vessels. These vessels are primarily sinusoid capillaries, which allow old blood cells to leak out. These old, damaged cells are then phagocytosed—taken up and eaten—by macrophages in the red pulp.

What does a lower percent saturation of hemoglobin with oxygen mean?

Remember that one way to examine these curves is by drawing vertical lines on the graph. If you draw a vertical line anywhere on this graph, you will see that the red-colored, right-shifted curve is almost always lower on that vertical line than the normal blue-colored curve.That means a lower percent saturation of hemoglobin with oxygen. This result also clearly tells us that that the right-shifted curve represents a lower oxygen affinity, and therefore more efficient unloading of oxygen from hemoglobin.

What percent of oxygen is carried on hemoglobin?

Remember that the vast majority—roughly 98 %--of oxygen transported in the blood is carried on hemoglobin in red blood cells.

How can you differentiate the atrial contractions from the ventricular contractions?

Tap lab table

Temperature and its affect on the heart

Temperature changes have a profound effect on nearly all biological processes. We can quantify temperature effects with a term called the Q10, or the temperature coefficient. The Q10 is a measure of how much the rate of a process increases with a temperature change of ten degrees. For most biological processes, the Q10 is around 2 or 3. This means, for example, that raising the temperature 10 degrees can cause an enzyme-catalyzed reaction to speed up about threefold.

What does the cortex of the thymus contain?

The cortex of the thymus is filled with developing T-cells, actively undergoing mitosis. This is where clonal expansion of T-cells takes place.

Describe a Direct ELISA

The difference between direct and indirect ELISA involves whether an antigen is being directly detected; or whether an antigen is being indirectly detected. In direct ELISA, a primary antibody that binds to the target antigen is conjugated to a molecule, such as an enzyme, that will aid in generating a visually-detectable signal.

Define Electrocardiogram

The electrocardiogram or ECG is obtained by placing electrodes on skin surface. Under suitable conditions, electrical activity generated by the heart, and conducted through body fluids, can be detected at the body surface. The electrical activity detected there is amplified and filtered. There is a normal pattern but various pathological conditions produce characteristic changes in this pattern.

What are the electrodes recording? what is the force transducer recording?

The electrodes are recording the ECG while the force transducer is recording the mechanical activities. (contraction and relaxation)

What is the first wave of electrical signaling initiated by?

The first wave of electrical signaling in a heartbeat is initiated by a group of pacemaker cells at the top of the heart in what is called the sinoatrial, or SA, node. Because heart muscle cells permit "spread" of electrical charge to adjacent muscle cells, this initial wave travels across the wall of the atrium from the SA node to the atrioventricular, or AV, node. Action potentials pass slowly through the AV node, which allows the atria time to contract. After that, action potentials pass rapidly along the atrioventricular bundle, which extends from the AV node into the interventricular septum. Thus, electrical signaling from the SA node causes the contraction of the atrium, which pushes blood into the ventricles

The five types of leukocytes are divided into what two classes?

The five types of leukocytes are divided into two distinguishable classes, granulocytes and agranulocytes, based upon the presence or absence of visible organelles called granules.

Is there mixing of oxygenated and deoxygenated blood In the frog heart?

The frog heart only has one ventricle, so there is some mixing of oxygenated and deoxygenated blood in the ventricle.

Describe the normal hematocrit values

The hematocrit refers to a percentage value; it is the fraction of whole blood volume that consists of red blood cells. The normal hematocrit value is around 45%. This value is slightly higher in adult males than adult females. This difference is largely due to the testosterone level difference found between males and females. Testosterone increases erythropoietin levels and promotes the generation of red blood cells. Hematocrit number changes in several physiological and pathological situations and could provide useful information for clinical diagnoses.

Describe the production of antibodies

→ B cells detect antigens on the pathogen in the lymphoid organs. → B cells then differentiate into plasma cells and produce and secrete antibodies.

There are four broad classes of pathogen against which the immune system helps provide protection:

→ Bacteria, such as salmonella. → Viruses, such as HIV. → Fungi, such as the ringworm fungus. → Other parasites such as microscopic protozoans and larger parasitic worms. Pathogens in the body may have many different types of identifying molecules, such as adhesion molecules on the surfaces of bacteria, or exotoxins secreted from bacteria. Virus surfaces typically feature numerous glycoproteins. Any of these molecular markers may be detected by antibodies.

What are the agranulocytes?

lymphocytes and monocytes Technically, they still have granules in their cytoplasm, but these granules are much smaller, so often they are overlooked. Lymphocytes and monocytes belong in this group.

Describe relationships between ECG and finger pulse data. (Make sure to discuss time differences and the physiological events associated with the traces.)

The relationship between ECG and finger pulse data is that after a full electrical trace (ECG), we then see a pulse trace. The said finger pulse trace occurs directly after the completed ECG trace due to the fact that finger is distant from the heart, meaning the time difference between the two is due to the distance needed to be traveled by the blood to the finger. In other words, upon completion of the ECG, blood is pushed out of the heart to be transported around the body, causing a subsequent pulse rate detection in the finger once the blood arrives.

What does the immune system protect against?

To begin our discussion of ELISA, we remind you that the immune system protects against pathogens which can be considered any infectious agent (e.g., viruses and microbes). To do this, the immune system must recognize pathogens as foreign to self.

Describe step 1, preparing the reference axes

To calculate the QRS axis, Let's move the three sides of the Einthoven's triangle and superimpose them at the zero points as shown on the right. Note that, when we do this, we keep the same orientation of these three sides. For example, the direction of each lead is retained and the plus (+) and minus (-) signs are still in the same place. To illustrate this, we have labeled the lead names at their positive ends. The reason that we moved the sides of Einthoven's triangle, also known as the reference axes, is because we will be using them to calculate the mean QRS axis.

Describe antibodies and why they are expressed by the immune system

To understand why certain blood types are incompatible, we need to introduce a new concept: antibodies. The immune system produces antibody proteins when a person is exposed to a foreign substance, for example, a protein on a bacterial cell wall. The bacterial protein would be termed an "antigen" since it is an "antibody generator". Upon exposure to an antigen, B lymphocytes will differentiate into plasma cells and make an antibody specific to that antigen. Any one given antibody is engineered to recognize and immobilize a specific antigen that your immune system perceives as foreign to your body. So a specific antibody is going to identify a pathogen (such as a bacterium or virus) presenting that particular antigen, it will bind to the antigen, and neutralize the pathogen or target it for destruction.

Which tube contains sheep blood? What features in the slide are you looking for to make this determination?

Tube B is the clear positive result, meaning it is the one to contain sheep red blood cells. To determine this, we looked for the presence of plaques (irregular and diffuse in appearance) in the featured slide.

What is the partial pressure of oxygen at the lungs?

Typically, the partial pressure of oxygen found in the alveoli of the lungs is near 100 millimeters of mercury. At this pressure, imagine a vertical line drawn upwards towards the sigmoidal oxygen-hemoglobin curve. We can see that hemoglobin is nearly 100% saturated with oxygen at this partial pressure of oxygen.

What causes a right shift in the hemoglobin curve?

Under certain conditions, for example, higher carbon dioxide levels, the behavior of hemoglobin changes in such a way that the graphical representation of its percent binding to oxygen shifts to the right. This shift moves the P50value to the right as well, making it a higher value; that is, a higher partial pressure of oxygen at which the hemoglobin will become 50% saturated. We can interpret this shift as meaning that the hemoglobin now has a lower affinity for oxygen

What do you use a hemoglobinometer for?

Use of the hemoglobinometer is the technique that directly assesses the hemoglobin level in blood. It is a relatively simple procedure where you insert the card into the machine, add a drop of blood, and read the measurement. One thing that is worth mentioning is that the unit is measured as grams per 100 mL or grams percent. The normal range for hemoglobin measurement falls roughly between 10 and 20 gram percent.

How can we view all the components of the layers of blood?

We can view all these components by preparing a slide called a "blood smear," as shown here. All you need is a small amount of blood, a drop of which you place on a slide. Then you use a second slide to spread the drop of blood across the first slide, basically smearing it. Then you are ready to view all these components under the microscope.

Describe the shape of an antibody

We should note that an antibody is a Y-shaped molecule, therefore, an antigen can bind to either antigen binding site, on each of the two arms of the Y. On the next slide, we will see that having TWO antigen binding sites is significant.

Describe Step 6: Repeat the process for the second lead

We then repeat this process with Lead II. The height of the R wave in Lead II is 14 mm. Since there is no Q or S wave, the height of the overall QRS complex is 14 mm. From the zero point in the middle, measure 14 mm distance on Lead II (the green line) and plot this amount. Pay attention to the direction in which you plot it. It should be in the positive direction.

Describe mechanism for how cold Ringer's decreased heart rate.

When cold ringer's was applied to the frog heart, heart rate decreased. The cold temperature decreases the efficiency of enzymes involved in mechanical contraction, therefore decreasing overall heart rate and contractile force. Essentially, everything within the heart is moving slower, meaning Ca2+ is diffusing into the cytoplasm at a slower rate than normal, causing heart rate to slow down due to the contractile cycle not completing itself as quickly as usual.

What to do if heart stops while applying ACh

When examining the effects of Ach, the heart might stop if the concentration is too high. If this occurs, quickly wash the heart with warm ringers. You can also apply a few drops of isuprel or massage the heart.

Describe the flow of positive current moving from negative to positive

When positive current moves from negative to positive, it will create a positive deflection in a trace.

Calculating Hemoglobin saturation:

% Hemoglobin Saturation = (A - B)/(A - C) x 100% A: Absorbance at 660nm of deoxygenated hemoglobin B: Absorbance at 660nm after each pressure reduction C: Absorbance at 660nm of oxygenated hemoglobin PO2 = (air pressure measured in mm Hg) x 0.21 Here is a reminder of our calculations for the lab. We calculate the percent saturation of hemoglobin with oxygen at each partial pressure using each time the difference between the measured absorbances for our fully deoxygenated, A, and fully oxygenated, C, reference points as the denominator. We subtract each absorbance measurement from the pressure reductions, B, from the fully deoxygenated reference point, A, and use that difference as our numerator. The quotient of A minus B over A minus C is multiplied by 100% to yield a percent saturation. Please remember that the partial pressure of oxygen in the air is calculated as the barometric air pressure in millimeters of mercury times 0.21, which is the mole fraction of oxygen in air.

Calculate % Saturation after each deoxygenation step using following equation:

% Saturation = (A-B)/(A-C) x 100% A = Absorbance after complete deoxygenation B = Absorbance after each deoxygentation step C = Absorbance before deoxygenation

The different leukocytes descriptions

- Lymphocytes - A large, darkly stained, spherical nucleus occupies most of the cell. - Monocytes - Usually contains a large, darkly stained "U" or kidney- shaped nucleus. - Eosinophils - Show large red granules in a clear cytoplasm. The nucleus is bi-lobed. - Neutrophils - Have fine reddish granules in a pale pink cytoplasm. The nucleus has 3-5 lobes. - Basophils - Have a clear cytoplasm with purplish-black granules. The nucleus is "S" or "U" shaped. LOOK AT CHART IN LAB

What are the trabeculae?

- numerous muscular strands and cords: the trabeculae The trabeculae, which give the ventricle a spongy texture, provide a site of attachment for papillary muscles, and may help serve both to reduce suction against the heart wall and to limit mixing of oxygenated and deoxygenated blood flows.

Describe the walls of arteries

As you can see, arteries have a thick wall and do not collapse when cross-sectioned.

Experimental tips for spectrophotometers

A few tips for using a spectrophotometer. Be sure to set the spectrophotometer to absorbance mode. If not, you will not be properly able to apply Beer's law to your data. Also, remember to calibrate the spectrophotometer by zeroing the absorbance reading with a blank cuvette tube between samples. Remember that the spectrophotometer must be turned on for 10minutes to warm up properly. Wipe your cuvette tubes with a kimwipe before placing them in the spectrophotometer to avoid having prints or other smudges contribute to light absorbance. If you are unable to close the lid on the spectrophotometer, cover the opening with a dark cloth to prevent the light entry into the sample.

Factors affecting the oxygen-hemoglobin dissociation curve

A number of additional factors such as pH (Bohr effect), PCO2, temperature, and diphosphoglycerate (or DPG), influence the oxygen-hemoglobin dissociation curve. In this exercise, you will investigate one of these factors as compared to a "normal" or "control" hemoglobin sample. For example, the bovine hemoglobin solution that you will be using may be "stripped" of its DPG during the preparation process. As a result, the dissociation curve will be shifted considerably to the left of its normal position, indicating a higher O2 binding affinity (see Figure below). When DPG is added back to the HbO2, the curve will show a shift to the right (decreased O2 binding affinity) and have a closer resemblance to the "normal" curve. DPG is produced by the RBC and is bound to the beta chains of deoxyhemoglobin. As a result, DPG causes HbO2 to release additional oxygen to the tissues. In this exercise you will use a spectrophotometer to quantify the oxygenation of a hemoglobin sample at different partial pressures of oxygen. The spectrophotometer is used to monitor the proportion of oxyhemoglobin present in the sample because oxyhemoglobin absorbs less red light at a wavelength of 660 nm than does deoxyhemoglobin. From the data obtained, you can construct oxygen dissociation curves for the two hemoglobin samples tested.

What is the complement system?

A group of serum proteins that act in a cascade to destroy invading microbes; these function to keep blood pathogen-free → This slide provides a quick reminder of the many functions of the complement system and the many immune cell types with which complement may interact. Take note that complement proteins play roles both in innate non-specific immunity, as well as in adaptive specific immunity. → Remember that one function of antibodies is to serve as a beacon for complement protein—providing a binding site for the C1 complement protein (Fig. 10). Through the classical complement pathway, two important proteins are produced: C3b protein, which allows macrophage attachment to the pathogen, thus facilitating phagocytosis. Additionally, and importantly for our purposes, C3b also helps initiate the formation of the membrane attack complex protein, or MAC. → The membrane attack complex, which is a large pore, inserts into the membrane of the pathogen and promotes lysis by allowing cellular contents to spill out (Fig. 11). → A consequence of the lysis is the death of target cells—in our case, sheep red blood cells. This cell death then results in visible gaps, or plaques in the blood smear, which is what we should observe in lab. Again, this lysis only becomes possible when antigen-containing target cells are mixed together with antibodies, or antibody producing cells, and mixed with complement protein.

Hemolytic assay - immunization process

A mouse is immunized by administering an intraperitoneal inoculation of sheep red blood cells (SRBC) four to five days. The immune system of the mouse recognizes SRBC's as a set of foreign proteins (antigens) and mounts an initial attack against them by proliferation of a specific set of B-cells. The B-cells secrete antibodies capable of recognizing and binding to antigens on SRBC's. Once antibodies are bound to SRBC surface antigens, the immune system begins the next stage of protection. The antibodies bind to complement, which is a group of circulating enzymes in blood. Normally inactive, bound complement is "activated". This initiates a cascade of enzymatic reactions that ultimately result in lysis (destruction) of SRBC (target cell). This process is schematically represented below. (Refer to PreLab for more details.)

What is the role of complement in the immune response?

A second line of defense, the complement of the immune system is a group of over 20 types of proteins of which carry out pathogen destruction. Through the use of a membrane attack complex (MAC), the complement system ultimately makes holes in the membrane of pathogens to kill them.

What are the three components of a spectrophotometer

A spectrophotometer has three essential components: a light source, a sample loading position, and a light detector. --> The light may be focused through a lens, and a specific wavelength of light selected with a monochromator for passing through the sample. --> The detector is usually coupled to a digital display of light intensity. --> The sample is held in a small quartz chamber called a cuvette.

The different types of leukemia

Acute Myelomonocytic Leukemia - This disease is characterized by an overproduction of monocytes andmyeloblast-derived blood cells (basophils, eosinophils and neutrophils). Chronic Lymphocytic Leukemia - This disease is characterized by large numbers of abnormal lymphocytes. Acute Monocytic Leukemia - This form of leukemia is characterized by an overproduction of monocytes.

Describe the parts of the spleen

Along the outer edge on the left-hand side is the capsule, from which short projections called trabeculae, enter the spleen tissue. The capsule and trabeculae are mostly connective tissue and smooth muscle, which help provide support to the spleen.

Describe the rearrangement of beers equation

Although Beer's law itself deals with an exponential relationship between initial and final light intensities, the equation can be rearranged (in a manner not shown here) to yield a linear relationship between absorbance of light and concentration of the sample under study. In this linear equation, Absorbance = e l c, where epsilon is the molar extinction coefficient, l the optical path length through the sample cuvette, and c the concentration of the sample. For a given substance, the molar extinction coefficient is a constant, and in any given spectrophotometer, the path length of light through the cuvette will also be a fixed value. This means that if epsilon and path length are known, the concentration, c, of the sample, can be calculated directly from the absorbance read at the detector.

What is an antigen? Can an antibody be an antigen?

An antigen is a protein on the surface of a pathogen (disease causing agent) of which will generate an immune system response. Despite clear shape differences, it is possible that an antibody could be an antigen as it too can be used to detect foreign pathogens in the body through the use of similar antibody binding processes of which are also carried out by an antigen.

Arterial Blood Flow

An understanding of the path of blood flow through arteries will help you to remember the pattern of arteries in the body, so that you will be better able to study and identify vessels on the practical exam. Oxygenated blood is pumped out of left ventricle through ascending aorta, which curves into aortic arch. In humans, there are three main branches of aortic arch: (1) the brachiocephalic trunk on right side (brachiocephalic = arm and head; branches into the right common carotid artery and the right subclavian artery), (2) the left common carotid artery, and (3) the left subclavian artery. The common carotid arteries travel along either side of the trachea and supply blood to the head and neck. Note: In sheep heart, the aortic arch has only two branches: brachiocephalic artery and left subclavian artery. The subclavian arteries (under clavicle) are the main arteries that supply blood to arms. The left subclavian artery emerges directly from aortic arch, while right subclavian artery is a division of brachiocephalic trunk. After the subclavian artery passes over the lateral border of the first rib (in armpit area) it is renamed the axillary artery. When the axillary artery passes the inferior border of shoulder blade, as it travels down the humerus it is renamed the brachial artery. At the elbow, it branches into ulnar artery and radial artery, which supply the forearm and wrist. The aortic arch curves inferiorly and becomes the descending thoracic aorta (above the diaphragm) and descending abdominal aorta (below the diaphragm). As the descending aorta travels through the abdomen, three unpaired arteries emerge from anterior wall of aorta to supply the gastrointestinal tract. From superior to inferior these are: (1) the celiac trunk, (2) the superior mesenteric artery, and (3) the inferior mesenteric artery. The celiac trunk branches into three other arteries that supply the stomach, duodenum, liver, and spleen. The superior mesenteric artery supplies blood to most of the small intestine, pancreas, and proximal part of the large intestine. The inferior mesenteric artery supplies blood to much of the large intestine. The right and left renal arteries exit the descending aorta laterally, at the level just inferior to the superior mesenteric artery. They carry blood to the kidneys to be filtered. The descending abdominal aorta bifurcates at the level of the 4th lumbar vertebrae (in the region of the iliac crest of the hip) into the right and left common iliac arteries. Each common iliac artery splits into an internal iliac artery (supplies pelvic area) and an external iliac artery, which is the main arterial supply for the lower limb. As it passes inferior to the inguinal ligament, the external iliac artery becomes femoral artery. Hopefully, this information will help you better use your vessel model to study the anatomy of human vasculature.

What is another consequence of hemaggulation

Another consequence of hemagglutination subsequent to transfusion of incompatible blood types, is that donor blood cells can block smaller blood vessels.

Describe the structure of antibodies, what regions do they have?

Antibodies are Y-shaped, with a base called the "constant," or Fc region and two arms, each of which has an identical Fab, or antigen-binding region. Each antibody is very specific to one particular antigen. It is the unique structure of the Fab region that confers this specificity. Antibodies serve many different specific functions, all of which generally serve to help identify, neutralize, and destroy pathogens.

Describe the different types of antibodies in relation to blood type

Antibodies specific for the A antigen of the ABO blood groups are called anti-A antibodies; antibodies to the B antigen are called anti-B antibodies. Because antibodies are made for things your body considers foreign, individuals with blood type A will have anti-B antibodies, and vice-versa.

Define antigens

Antigens are molecules that are found on the surface of pathogens and are specific to that particular pathogen. Once recognized, the antigen will elicit an immune response mediated by the production of antibodies specific to the antigen. The antibody then 'marks' its target antigen and the associated pathogen for destruction by circulating phagocytic white blood cells.

Describe the reading for the ECG trace

Any one ECG trace we see is recorded from one lead (including one positive and one negative electrode). The actual reading is the voltage difference between the positive and the negative electrode. For example, in lead I the left arm electrode is designated as positive and the right arm electrode is designated as negative. If you only record lead I, you do not need to attach the electrode to the left leg. However, we DO connect a third electrode to the right leg (Fig. 2). This electrode is inactive and serves as a reference to ground. This is to improve the quality of the signal. Of course, you can record multiple leads simultaneously by connecting yourself to more electrodes.

Describe the size of openings when comparing arteries and veins

Arteries and veins both have openings in the middle. Veins have a larger lumen (interior cavity) and usually collapse when no blood is inside.

What effects do Isuprel (Isoproterenol) and Acetylcholine (ACh) have on heart rate?

As depicted by our data, Isuprel increased heart rate while Acetylcholine decreased heart rate. Isuprel increases heart rate through its ability to activate beta-1-adrenergic receptors, ultimately increasing the amount of cAMP which opens HCN channels to bring the pacemaker cells to threshold and begin contraction. On the other hand, acetylcholine activates the parasympathetic system, better known as the "rest and digest" system, which aims to conserve energy by slowing heart rate, increasing gland activity, and relaxing the gastrointestinal tract.

Describe the set up of the Einthoven's triangle

As illustrated on the left, we labeled three sides of Einthoven's triangle, where each side corresponds to a lead. So, we have three bipolar leads - Lead 1 is labeled as blue, Lead II green, and Lead 3 as red. When heart is beating, electrical signals generated in the heart initiate heart beats, and these electrical signals can be detected using each lead. Getting electrical information from three leads is much like looking at the same object from different angles. With any two of these leads, we will be able to get a complete picture of cardiac electrical activity on the frontal plane.

Oxygen- Hemoglobin dissociation curve

At any given concentration of oxygen, a certain portion of hemoglobin molecules will be in the form of oxyhemoglobin. If we were to plot amount of oxyhemoglobin (i.e. % saturation of Hb with O2) versus oxygen concentration (i.e. partial pressure of oxygen, PO2) we would obtain an oxygen-hemoglobin dissociation curve (Figure below). Note characteristic sigmoidal shape of this curve. The curve clearly shows that binding of O2 to Hb is dependent on partial pressure of oxygen, PO2. The upper plateau of sigmoid curve ensures that Hb remains almost fully saturated in light of any respiratory/circulatory abnormalities as is typically experienced in old age, illness, or a low oxygen environment (e.g. high altitude). As can be seen in this figure, at a PO2 between 80 - 100 mm Hg, most HbO is saturated (i.e. in the form of oxyhemoglobin, HbO). At lower PO2 levels (< 80 mm Hg), oxygen is released leading to formation of deoxyhemoglobin (Hb). At a PO2 of about 27 mm Hg, only half of Hb is present as HbO. This point is called the half-saturation pressure or P50. As the PO2 decreases even further, more oxygen is given off until at a PO2 of zero, the hemoglobin is fully deoxygenated (all hemoglobin is present as Hb).

Describe atherosclerosis

Atherosclerosis impairs flow of blood and hence oxygen to myocardium leading to coronary artery disease and heart attack (myocardial infarction). It is also a contributing factor to heart disease and strokes. Fats (lipids) begin to accumulate on arterial walls when we are children forming what are called fatty streaks. In adolescence, fatty streaks become covered with fibrous tissue and muscle, forming fibrous plaques. As we age, plaques accumulate more layers of cholesterol, fibrous and muscle tissue, and may also accumulate calcium which causes plaques to harden. As the lumen of the artery becomes narrower, blood flow is restricted. If the vessel becomes totally obstructed, blood flow to downstream tissues is blocked resulting in cell death and tissue necrosis.

Atrioventricular node

Atrioventricular (AV) node: Electrical connection between atrial muscle and ventricular muscle, also serves as backup pacemaker.

What receptor does atropine block to increase heart rate? Can you think of an instance where having atropine in an ambulance would be beneficial?

Atropine blocks muscarinic acetylcholine receptors. Such receptors inhibit postsynaptic neurons in an effort to slow and decrease both heart rate and contractile force through the activity of acetylcholine. If a patient in an ambulance was experiencing an extremely slow heart rate (bradycardia) due to a medical emergency, a paramedic could inject atropine into the patient in order to block the activities of the parasympathetic nervous system, of which would bring the heart rate back up to an acceptable rate (due to the blocking of muscarinic receptors).

What is atropine?

Atropine can be used as a cholinergic antagonist that will prevent activation of muscarinic acetylcholine receptors, or mAChR's.

What do the erythrocytes and Buffy coat form together?

Collectively, the erythrocytes and the components of the buffy coat are called the formed elements. We don't call them cells, because these fractions contain fragments that break off from larger cells.

Pre Lab

Compare and contrast a human and frog heart Predict how temperature may affect cardiac function Predict how different extracellular ionic concentrations may affect cardiac function Discuss how different neurotransmitters may affect the performance of the heart Describe the experimental setup and list common troubleshooting techniques

Compare arteries and veins in relation to tunica externa

Compared to the artery, veins have a very thick tunica externa, which is composed of areolar connective tissue that helps anchor the vessel to other structures.

Compare arteries and veins in relation to the tunica media

Compared to the veins, Arteries have a thick tunica media (middle layer of blood vessels) which is composed of circularly arranged smooth muscle cells.

A slight to moderate increase in the extracellular concentration of potassium ions should...

DECREASE the concentration gradient because such a change will bring the concentration of potassium inside the cell and outside the cell closer together in value.

Describe blood circulation in the frog

Deoxygenated blood from the systemic circulation throughout the body returns to the right atrium through the sinus venosus; oxygenated blood from the lungs and skin returns to the left atrium through the pulmonary vein. The oxygenated and deoxygenated blood flows remain separate until they enter the ventricle. The single ventricle then pumps the blood out through one large artery before further separation into smaller vessels. But as noted before, the anatomical organization of the ventricle and the internal structure of the artery allow only a small amount of mixing of the two pools of blood. The consequence of this separation is that blood that is primarily oxygenated is delivered to the brain and internal tissues, whereas blood that is primarily deoxygenated flows to the lungs and skin. (Remember from last semester that frogs exchange gases and water through their skin, so the skin serves as another respiratory surface for frogs).

Based on your knowledge on oxygen-hemoglobin binding features, explain figures above. If your results do not match with your prediction, explain what you think should happen.

Despite my results not displaying this concept perfectly, based off my knowledge on oxygen-hemoglobin binding features, I can conclude that absorbance decreases as the percent saturation of oxygen increases. As hemoglobin binds to more oxygen, its properties change, one of which includes a change in the optimum wavelength of absorption of maximum light. Therefore, due to the properties of the blood itself changing, absorbance decreases as a result.

Physiology of hemoglobin-oxygen binding

Diffusion based respiratory gas exchange (oxygen and carbon dioxide) is sufficient enough to meet metabolic requirements only in very small organisms. For most invertebrates, simple dissolution of oxygen in blood is sufficient to meet the organism's needs. However, this arrangement would not supply enough oxygen to meet metabolic needs of most vertebrates. Therefore, most larger organisms have evolved a circulatory system which allows for bulk transport of gases to and from tissues. Here, special proteins called respiratory pigments, are employed to reversibly bind oxygen (O2). Hemoglobin (Hb) is a respiratory pigment found in vertebrate circulatory system. In this week's lab, you are going to learn techniques that will allow us to quantify levels of oxygen binding to hemoglobin (Hb) and investigate factors that may contribute to dynamics of binding of O2 with Hb.

What could contribute to angle that is outside of the normal range? (Comment: Abnormality results from your experiment is likely due to a setup issue or calculation issue, instead of true pathological conditions. So please only include true pathological conditions here.)

Disregarding experimental faults, anything above 90 degrees could indicate changes in ventricular activation or something as dangerous as myocardial damage due to a myocardial infarction. In addition to these, hypertrophy, also known as enlargement of an organ due to increased cell size, could cause the angle to be outside of the normal range of 0 to 90 degrees.

What do we plot?

For practical purposes, we plot cardiac output, which depends on stroke volume—itself dependent on the contractile force—against right atrial pressure (or RAP), which can be used as a proxy measurement for tissue stretch. Note that within physiological limits, with higher right atrial pressure, the cardiac output increases up to a maximum value. Also notice that within the normal physiological range, cardiac output is highly sensitive to changes in Right Atrial Pressure. What this relationship means is that, when additional blood enters the heart, the additional blood volume stretches the muscle tissue so that the heart contracts more forcefully and thus ejects more blood. This provides an intrinsic mechanism by which stroke volume can match venous return (and also be maintained if aortic pressure rises). (The relationship is affected by circulating epinephrine, which increases the strength of contraction at any degree of stretch.)

Describe Step 2: Identify QRS complex complex on both leads

For the next step, you will need two ECG traces recorded by two different leads simultaneously. Let's use this trace as an example. First, let's identify R waves in these two leads (They are shown circled in blue).

Describe how hematocrit and hemoglobin are related

Hemoglobin and hematocrit are related because they each measure aspects of red blood cell levels. If the measure in either one is lower than normal, you have anemia. The hematocrit value gives you an idea of the proportion of red blood cells in whole blood, but it does not tell you the level of hemoglobin in the red blood cells. These numbers often times go hand in hand, but there are many cases where they are not directly related. For example, you might have a normal hematocrit, but if your hemoglobin level is low, you have anemia. Both measurements are needed to have a more complete picture of what is going on in your blood.

Describe the structure of hemoglobin

Hemoglobin is a four-subunit protein made up of two alpha and two beta polypeptide chains. Each subunit contains a central heme group, shown below, with an associated iron ion to bind oxygen. Each heme group can bind one oxygen molecule.

Describe what different levels of hemoglobin may mean

Hemoglobin is a oxygen-carrying pigment and the main component of red blood cells. Low hemoglobin levels may indicate anemia, recent hemorrhage or fluid retention. Elevated hemoglobin levels may indicate hemoconcentration from polycythemia or dehydration.

Describe the alteration between tense and relaxed state by hemoglobin

Hemoglobin subunits can alternate between a "tense" state, shown at left, where the subunits are less receptive to oxygen binding, and a "relaxed" state shown at right, where the subunits are more receptive to oxygen binding. Therefore, the tense state represents a low-affinity state and the relaxed state represents a high-affinity state.

What can a very high does of potassium do to concentrations of the cell.

However, a very high dose of potassium can make the EXTRAcellular potassium concentration higher than that on the inside, which reverses the concentration gradient. In this case, the cardiac myocyte will be unable to repolarize—because potassium will not flow back out of the cell spontaneously—and contraction will stop.

What is different about fetal hemoglobin?

Human fetuses express a different subunit of hemoglobin from those commonly expressed in adults. Note that the graph of hemoglobin subunit expression over developmental time shows that the gamma subunit is expressed at high levels in fetuses, in addition to high levels of the alpha subunit, and low levels of the beta subunit. This gamma subunit has a higher affinity for oxygen than the beta subunit and allows the fetal hemoglobin to draw oxygen from the maternal adult hemoglobin for use by the fetus.

Define hemaggulation and how it arises

If a person receives a blood transfusion from another individual whose blood is incompatible with his or her own (by which we mean expressing a different blood-type antigen) the immune system will recognize that foreign antigen and will therefore make antibodies targeting that antigen on the foreign red blood cells. Remember that the antibody has two binding sites, which means each antibody can bind to two blood cells. As each blood cell will have multiple antigens on its surface, there are multiple antibody binding sites, so that many red blood cells can be connected via antibody binding. The resultant clumping of many red blood cells together is called hemagglutination. This image shows an in vitro view of agglutination.

Describe angulation in the laboratory

If mixture remains uniform in appearance, there is no agglutination. (Well A or Well Rh0 in figure) If mixture has a granular appearance, agglutination has occurred (indicated by yellow arrow in figure).

How do you think increased extracellular K+ will affect cardiac function (rate/contractile strength)?

If we increase extracellular K+, then heart rate will increase, though no change in force will occur because an increase in extracellular K+ causes a decrease in the concentration gradient since the difference between K+ outside and K+ inside has decreased. This decrease in concentration gradient lessens potassium efflux, depolarizing the resting membrane potential, which in turn, increases the rate of action potential occurrence.

How do you think increased extracellular Ca2+ will affect cardiac function (rate/contractile strength)?

If we increase the amount of extracellular Ca2+, then heart rate and contractile strength will both increase due to the fact that the more calcium we have coming in through the L-type calcium channels, the more cardiac muscle contraction cycles can be initiated and the depolarizing calcium plateau will be more sustained.

How can we see separated components of blood? What two components is it separated into?

If we take a blood sample and place it into a centrifuge, then let it spin for several minutes, we can see blood separated in the manner we are seeing here. As we can see in the cartoon of the test-tube, whole blood is separated into a liquid part and cellular components.

What does the white pulp of the spleen contain?

If we zoom in on the details of the white pulp, we see a functional region of the white pulp called the lymphatic nodule, pictured on this slide (Fig. 7). The nodule abuts blood vessels such as arteries, and contains a germinal center, in which mature B cells proliferate, differentiate, and make antibodies. This is where B cell antibodies undergo somatic hyper-mutation and class isotype switching, to become even more specific for their target antigens.

How do you calculate packed red blood cell volume?

Image on computer

Principles of light

In order to have a better understanding of the concepts of spectrophotometry, some basic principles of light and its properties should be reviewed. Visible light makes up only a very small portion of the electromagnetic spectrum (Figure 1). Visible or white light covers a range of colors from violet to red and these colors correspond to range of wavelengths of 400 to 700 nanometers (nm) (see Table I). Shorter wavelengths (< 400 nm) constitute ultraviolet spectrum, x-rays, gamma and cosmic rays, while longer wavelengths (> 700 nm) comprise infrared region, radio waves, and microwaves. Our sense of vision is dependent upon perceiving only white light. While we can distinguish different colored solutions from one another and some differences in intensity within a hue, our eyes cannot achieve fine quantification within a specific range. This is where spectrophotometers becomes useful. Typically, spectrophotometers are designed to record measurements in either Transmittance (T) or Absorbance (A). Transmittance, which is fraction of light transmitted, is usually expressed as a percentage (%T = T (100)), while Absorbance (also called Optical Density, OD) does not have any units associated with it. In order to understand what these measurements relate to, we must delve into some physics.

Where are pacemaker cells located in frog hearts?

In the frog heart, the pacemaker cells that function equivalently to the human SA node are located in the sinus venosus, which we call the SV node. However, pacemaker cells are also found in frog ventricle, and in one of this week's experiments, you will try to separate these two populations and observe how the atria and ventricle can contract independently.

Describe blood flow carried out by the arteries and veins

In the systemic circulation, arteries convey blood away from the heart to the body and branch into smaller and smaller vessels until they feed into the capillaries where gas and nutrient exchange occurs. From the capillaries, veins return blood to the heart.

ELISA

In this case, antigen being studied is bovine serum albumin (BSA) which coats all wells. You will be testing samples to determine if they contain antibody to this antigen. "Positive" and "negative" Controls will also be tested. All samples are prepared in a buffer solution. Positive samples will contain 1˚ antibody raised in rabbits to this protein (Rabbit anti-Bovine albumin), negative samples will not. First you will perform a "blocking" step. In blocking step, gelatin is added to wells, allowing 1˚ antibodies attach to antigen only. This reduces false positives. The wells are rinsed afterward. Then add your sample. Following an incubation period, 2˚ antibody is added to complete Antigen / 1˚ Antibody / 2˚ Antibody sandwich. This conjugated antibody is Goat anti / Rabbit IgG / HRP. The HRP stands for "horse radish peroxidase" which is the enzyme conjugated to antibody. Lastly, a substrate called ABTS will be added. If the complex is present, ABTS will react with HRP creating a green-colored by-product in the reaction. If the complex is not present, no color change will occur. Based on results, you will be able to determine if 1˚ antibody is or is not present in the samples.

What is the mean electrical axis?

In this part of the tutorial we are going to discuss the mean electrical axis and how to calculate it. Using ECG traces, we are able to calculate mean electrical axis. Basically, it is the net direction of the depolarization or repolarization. We can determine an axis for each major ECG component, for example you can determine a net electrical flow for the P wave, called the P wave axis. The same is true for the QRS complex and T wave. The electrical axis could provide important information; for example, the P wave axis can tell us whether or not the SA node is driving the ventricles. The QRS axis can inform us about changes in the sequence of ventricular activation and can indicate myocardial damage. In our lab, we will be focusing on mean QRS wave axis, also known as ventricular mean electrical axis.

Describe the Buffy coat

The middle layer is a gray-white layer called a buffy coat. This layer includes platelets and various white blood cells, also called leukocytes.

Sheep Heart - Know these parts

Myocardium Right ventricle Chordae tendinae Aortic semilunar valve Endocardium Left atrium Papillary muscles Interventricular septum Right atrium Bicuspid (mitral) valve Pectinate muscles Tricuspid valve Left ventricle Pulmonary semilunar valve

Describe myoglobin

Myoglobin, which resides in muscle tissue, consists of a single subunit with only one heme group, and therefore exhibits no cooperativity. Note that the oxygen-myoglobin dissociation curve has a different shape from the sigmoidal hemoglobin curve. This shape is called hyperbolic. At most points of this graph, the myoglobin curve has a higher percent saturation of oxygen, indicating a higher affinity for oxygen. This difference allows myoglobin to draw oxygen from hemoglobin and to store that oxygen for use when oxygen partial pressures in the muscle become very low under exertion conditions.

Describe neutrophils

Neutrophils are most abundant white blood cell type, and their nuclei are multi-lobed; as many as five nuclear lobes interconnected by strands. So sometimes they are called polymorphonuclear, because of the many various shapes of their nuclei.

Which frog Ringer's treatment should show the largest force of contraction: normal Ringer's, Ringer's with moderately high calcium, or Ringer's with moderately high potassium? Do your results (tables and graphs) match what you expect?

Ringers with moderately high calcium should have the largest effect on force of contraction as calcium is important for initiating cardiac muscle contraction. The more calcium present within the cytoplasm, the more contraction that will occur, increasing heart rate. Due to the fact that our frog heart was deteriorating as we continued our experiment, our results did not depict what we would have expected. Although the addition of calcium increased heart rate mildly, the addition of potassium increased heart rate greatly, by over 100%. This increase in heart rate due to potassium is due to the fact that an increase in extracellular potassium decreases the concentration gradient. This then decreases potassium efflux, depolarizing the resting membrane potential and therefore increasing action potential firing. Both of the ions had a negative effect on force, decreasing it by an average of 9-11%.

Describe secondary lymphoid organs

Secondary lymphoid organs are sites where mature cells of the immune system aggregate and initiate a specific immune response. These organs include the spleen and lymph nodes.

Describe Step 5: Plot the QRS amplitude on the first lead

Since our calculated height of 2.5mm is for Lead I, we will put an arrow 2.5mm long on the blue line - and since it is positive, it is going towards the direction where we labeled Lead I, the positive terminal.

What does the mean QRS axis show?

Since the normal range (using even the tightest standard) is between 0 to 90, changes of the mean QRS axis provide useful clinical significance. It could indicate changes in the sequence of ventricular activation, such as left anterior fascicular block, or may be an indicator of myocardial damage, such as inferior myocardial infarction.

Sinoatrial node

Sinoatrial (SA) node: Pacemaker cells that propagate action potentials through muscle fibers of atria.

Spectrophotometry

Spectrophotometry is a commonly used analytical procedure. Usually a test sample is mixed with a specific reagent to form a colored product. Depending on color of product, it will have what is called an Absorbance maximum (also called lambda max: λ max), the wavelength where this substance shows maximal absorbance (See Figure 1 below). In addition, intensity of color in sample is related to amount of substance present. This can be quantified by comparing Absorbance of test sample to Absorbance readings of known concentrations called "standards." The Absorbance readings of standards are plotted against their concentration on what is called a "Standard Curve".

Describe Step 1 of an indirect ELISA

Step 1: In Step 1 of an indirect ELISA, purified antigen proteins are added to the wells of the microtiter plate. The antigens are bound tightly to the bottoms of the plastic wells. Between each step, the wells are washed with a mild detergent solution to remove excess proteins that are not bound to the plastic.

Describe the different types of blood types and why they are the way they are.

The ABO blood types are based on the presence or absence of two antigen variants that are expressed on the surface of the red blood cells, Antigen A and Antigen B. If only the A antigen is expressed on the surface of the red blood cells of an individual, this person's blood type is Type A. Similarly if only the B antigen is expressed on the surface of the red blood cells of an individual, this person has blood type B. Antigen A and B are genetically co-dominant, so it is possible for an individual to express both types simultaneously on the red blood cells; such individuals have blood type AB. In some populations, neither antigen A nor B is present; this is called blood type O. The ABO blood type is critical for making blood transfusions. If a patient receives an incompatible blood type, it can be fatal.

What is the ELISA assay used for?

The ELISA assay makes use of the basic principles of antibody-mediated immunity to detect antibodies or antigens in a laboratory sample. ELISA is an important diagnostic clinical tool to detect infection with specific pathogens. ELISA is both extremely sensitive and specific.

what does the frank-starling law describe?

The Frank-Starling law describes the length-tension relationship in the intact heart. In cardiac physiology, this law describes the relationship between the degree of stretch of the ventricular muscle—its length—and the strength of cardiac contraction, which can be measured as the tension produced by contraction.

What does the P wave represent?

The P wave represents atrial depolarization and is associated with atrial contraction.

What does the QRS wave represent?

The QRS complex represents ventricular depolarization but also contains atrial repolarization. Together, they initiate ventricular contraction and atrial relaxation.

What does the T wave represent?

The T wave represents ventricular repolarization and initiates ventricular relaxation.

Why is the adhesive property of the PVC plastic important?

The adhesive property of the PVC plastic is important because it allows for each well to be coated easily and efficiently with the desired antigen after proper addition and incubation in a manner so that they are not removed during rinsing cycles.

Describe the bottom layer, the red blood cells.

The bottom layer consists of red blood cells, also known as erythrocytes. Typically, this layer comprises about 44% of the blood.

Describe the hemolytic plaque assay

The hemolytic plaque assay is used to detect antibody-producing plasma cells. In our process, mice are immunized with sheep red blood cells (SRBC, Fig. 8). This process stimulates B cells in the mouse spleen to differentiate and secrete antibodies against sheep red blood cells. Procedure: In our procedure, we will mix together mouse spleen cells, complement protein, and red blood cells—either from sheep or another source (Fig. 9). In binding to anti-sheep antibody, complement protein will help poke holes in sheep red blood cells. This action of complement protein will lyse and kill the sheep red blood cells, leaving holes, or plaques, in the blood smear. → Hemolytic plaque assay: Mix together: Mouse spleen cells, Sheep RBCs (SRBC), Complement Incubate slide chambers.

Describe the tunica intima

The innermost layer is the tunica intima, and is composed of an endothelium and a sub- endothelial layer that is made up of a thin, areolar connective tissue. The innermost layer is a simple squamous epithelium lining and a thin layer of areolar connective tissue.

Describe sickle cell anemia

The key is the shape of the red blood cells. Normally, we see a classic biconcave shape to red blood cells. Sickle-cell anemia features abnormally-shaped, or sickle-shaped, red blood cells. Sickle-cell anemia is an inherited disease caused by a single point mutation in the gene for the hemoglobin beta chain. This change in its major intracellular protein makes a red blood cell adopt a sickle shape or crescent shape. This will cause these cells to have less capacity to carry oxygen and a far greater likelihood of getting stuck in small blood vessels, therefore slowing down blood flow and oxygen delivery.

Describe leukemia

The last blood disease we are going to examine in the lab is leukemia. As can be seen in the slides on the right, leukemia is characterized by unregulated overproduction of immature leukocytes. Very large numbers of these cells will be released from the bone marrow and found circulating in the blood. Leukemia is defined by the type of cells that are involved. For example, Myelogenous leukemia affects myeloid cells in the bone marrow, and lymphocytic leukemia affects lymphocytes. In the lab practical, you will be asked to identify leukemia, but you won't be asked to identify different types of leukemia.

Describe regular cardiac tissue

The left hand slide shows a normal myocardium. You can see quite clearly the branching, intercalated disks, striation, and central nuclei - such features as we have visited in the last semester.

What does the medulla of the cortex contain?

The lighter-stained medulla contains structures called Hassall's Corpuscles. Surrounding these corpuscles in the medulla are epithelial cells that help select against self-reactive T cells, to prevent autoimmunity. The purposes of the Hassall's Corpuscles themselves are not fully understood.

Explain how the lymphatic system is considered a second circulation in the body

The lymphatic system is often considered as a second circulation in the body. Like the blood circulation, the lymphatic circulation has small-diameter lymphatic capillaries that help collect excess interstitial fluid, which is also known as lymph (Fig. 2).

Major structures of the lymphatic system

The major structures of the lymphatic system are the lymph vessels, which carry lymph fluid, the lymphoid tissues, and the lymphoid organs (Fig. 1).

describe the mean QRS

The mean QRS vector normally averages +59°. (The range, however, is quite broad, ranging from 0° to 90°, sometimes even -30° to +110°). Excessive deviations from this range may indicate specific cardiac anomalies.

Describe polycythemia

The next condition you will observe in the lab is polycythemia. What you might notice is that the slide on the right seems packed much more with red blood cells. The density of the red blood cells is markedly higher. Indeed, this is a characteristic of polycythemia: an elevated proportion of red blood cells, either via an increase in the number of red blood cells or a decrease in blood plasma volume. Polycythemia can be a dangerous condition when the blood becomes too viscous, and can result in high blood pressure and blood clots. Primary polycythemia is a rare condition caused by factors intrinsic to red blood cell precursors found in bone marrow. Hormones like erythropoietin can increase production of erythrocytes. Chronic hypoxia and steroid hormones such as testosterone can also contribute to polycythemia. You might have heard about blood doping, which is a polycythemia associated with intentional transfusion of concentrated red blood cells.

Describe step 7: Find the intersection of the axis

The next step is a very important step to which it is essential to pay close attention. From the end of each arrow we have drawn on the Lead I and Lead II axes, draw another dashed line perpendicular to each axis, as shown here. Extend both dashed lines until they intersect. The fact that the intersection it outside the bounds of the three lead lines doesn't matter.

Describe the technique of hematocrit

The other technique that we are going to use to assess the amount or proportion of red blood cells is called hematocrit. This technique makes use of a centrifuge to separate whole blood into its liquid part and cellular components. The liquid part stays on the top since it is the lightest portion. This is the blood plasma. In the middle we find a small layer of buffy coat, composed of white blood cells and platelets. The bottom part consists of red blood cells.

Which system has less effect on contractile force?

The parasympathetic has less effect on contractile force due to the lack of parasympathetic innervation to the ventricles.

Why is the spleen used in the Hemolytic plaque assay?

The reason as to why the spleen is used in the hemolytic plaque assay is due to the fact that it creates ample antibodies within its white pulp upon stimulation of its B cells. These antibodies then cause an immune response against the foreign sheep red blood cells, which ultimately causes the plaque we see in positive assays. Essentially, the main function of the spleen is to 1. filter the blood and 2. help initiate immune responses within the body. Therefore, the spleen is primed to detect pathogens and quickly produce antibodies, this action allowing us to see the results of the plaque assay.

What are the leads detecting?

What the leads detect is the projection of the actual wave towards each lead. Thus, each lead records the heart electrical activity from a different angle. This is one reason we use multiple leads to assess heart function. Like looking at a house, you need to look from the front, back, left and right sides to have a good idea of what it looks like. With three leads, it can provide a complete picture of electrical activity on the frontal plane.

What are the spiral folds?

The spiral folds in the vessels leading out of the heart help guide blood flow from the atria to the systemic and pulmocutaneous arteries while maintaining separation of oxygenated and deoxygenated blood.

What does the spleen function to do?

The spleen is a storage site for platelets. It has two other main functions, which are: 1. Filter the blood—specifically, removing old red blood cells and platelets from circulation. 2. Help initiate immune responses: reacting to blood-borne antigens, by producing antibodies from local B-cells.

What are the functions of the lymphatic system?

The three major functions of the lymphatic system are: 1. To maintain fluid balance in the body 2. To help participate in immune responses for protection against pathogens 3. Absorption of lipids from the digestive tract

Describe the lobule of the thymus and its corresponding parts

The thymus has characteristic gross-level histology, which reveals lobules (See image below for general location). Each lobule has a dark-staining outer cortex and lighter inner medulla. The lobules are surrounded by a supporting capsule.

Describe the tunica external

The tunica externa is the outermost layer, and is composed of areolar connective tissue that contains elastic and collagen fibers. This layer helps anchor the vessel to other structures.

Describe the tunica media

The tunica media is the middle layer, which is composed of circularly-arranged smooth muscles. Vasoconstriction is achieved by contracting this layer.

What is the tunica? How many layers are there?

The walls of both arteries and veins have three layers, called tunica. These tunica include the tunica intima, the tunica media, and the tunica externa.

Describe the function of the AV node

Then, the AV node relays electrical impulses to the AV bundle which projects to the purkinje fibers whose electrical signaling initiates contraction of the ventricles. This contraction pushes blood out of the heart into the aorta and pulmonary arteries.

What are the five different types of white blood cells? How can you remember which has the most vs. which has the least?

There are five different types of white blood cells: neutrophils, lymphocytes, monocytes, eosinophils, and basophils. Consider the sentence: "Never Let Monkeys Eat Bananas". The first letter of each word in this sentence corresponds to the first letter of a type of leukocyte, and is in the same order as the relative abundance of each type of associated white blood cell.

How is oxygenated blood separated from deoxygenated blood in the human heart?

There are many structures that help to separate oxygenated blood from deoxygenated blood in the ventricle. In the human heart, there are two separate ventricles divided by a septum, which, from our perspective, makes things much simpler

Describe the two types of immune responses (cell mediated, humoral).

There are two paths of which the immune response can take. To begin, the cell mediated response involves cell to cell communication dealing with infected somatic cells. Executed by cytotoxic T cells, of which include both memory T cells that defend against the infection if it occurs again and effector T cells of which carry out the killing of infected cells, this path results in the lysing of the infected cell. Through binding with the epitopes on antigens of infected cells, molecules are released of which cause lysing of the cell, releasing the pathogen and other contents into the blood stream. Upon entrance to the blood stream the other path, the humoral response, takes over. The humoral response consists of the blood soluble molecules produced by B cells, antibodies. These antibodies recognize and bind to antigens on the surface of pathogens in order to prevent the spread of infection through neutralization, agglutination (clumping), and opsonization (expose C region of pathogens). Check Answer

Define White blood cells

These cells help initiate immune responses and defend the body against pathogens. They are about 1.5 to 3 times larger than erythrocytes . Leukocytes are motile and remarkably flexible. In fact, most leukocytes are found in body tissues, as opposed to in the bloodstream.

Where do lymphatic ducts retro collected lymph to?

These lymphatic ducts then return the collected lymph fluid to the blood circulation at the subclavian veins.

What Willa. decrease in gradient do to potassium efflux?

This decrease in gradient reduces potassium efflux, which depolarizes the resting membrane potential. As you recall from last semester, this should increase the rate of action potential firing.

Hemoglobin dissociation curve

This property of cooperativity in hemoglobin also accounts for the characteristic shape of the oxygen-hemoglobin dissociation curve. This curve plots the percentage of heme groups bound to oxygen against the partial pressure of oxygen in millimeters of mercury. We can treat partial pressure as a proxy measure for oxygen concentration. If you look at the curve from a short distance, you can see that it faintly evokes the shape of the letter s. Because this is a scientific concept, we call the s-shape of the curve by the Greek letter sigma. Hence, this is a sigmoidal curve.

When a depolarization wave is moving from the SA node to the AV node, what is detected on lead I?

When a depolarization wave (which is a positive wave) is moving from the SA node to the AV node, what is detected on lead I is a positive wave moving from the negative electrode to the positive electrode, generating an upward deflection in the trace.

Explain oxygen-hemoglobin dissociation curve shown above. Which treatment did your group test? Does your treatment cause a left shift or a right shift? If your results do not match your prediction, explain what you think should happen.

When testing a low pH affects on oxygen-hemoglobin binding, it can be concluded that the lower the pH, the higher the acidity level in the body system and therefore the less affinity hemoglobin has for oxygen. This lower affinity for oxygen allows hemoglobin to release its oxygen into the tissues more often than it would under regular conditions, carrying out homeostatic maintenance. In other word, this effect of low pH causes a rightward shift in our oxygen hemoglobin dislocation curve. Our displayed data, although showing a bit of a rightward shift, does not show a great difference between the control system and the treated system. This could be due to the fact that we had leaky valves and were unable to produce the desired pressure.

Sheep dissection video:

When the heart is facing towards you, the left side of heart is your right side and vice versa. - Pulmonary trunk - Auricle: flap like structure - Blood flows into the heart through the inferior vena cava and the superior vena cava - Blood flows out to the lungs through the pulmonary trunk - Blood returns to the heart from the lungs through the pulmonary veins - From the left ventricle, blood flows out of the aorta. - Pectinate muscles - Look for pulmonary trunk and the interventricular sulcus to orient the anterior side of the heart - Rewatch video for clarification

What is true of partial pressure and oxygen saturation at the tissues?

When those same oxygen-loaded hemoglobin molecules enter the capillary beds of the peripheral tissues, the partial pressure of oxygen is much lower, around 40 millimeters of mercury. If you look at the dotted vertical line drawn upwards from the x-axis at 40 millimeters of mercury, you will note that the hemoglobin dissociation curve at this partial pressure reads roughly 78% saturation. What this means functionally is that hemoglobin has dropped off about 22% of the oxygen that it held at the lungs so that the tissues can use it.

What are the granulocytes?

When you observe them under the microscope, Granulocytes show clearly-visible microscopic granules in their cytoplasm. Three types of leukocytes fall under this category: neutrophils, eosinophils, and basophils. They are named based upon how the granules are stained.

Describe an electrocardiogram and the science behind why we can measure with these

When your heart beats, it generates small electrical signals. Because your body fluid are made up of salt solutions which are good conductors of electricity, by placing surface electrodes at different parts of your body, it is possible to record these small signals as waves on an electrocardiogram, or an ECG. This is sometimes also called an EKG. ECG/EKG is widely used and serves as one of the most important diagnostic tool for heart conditions.

Why is calcium important in the heart?

While the majority of the cytosolic calcium responsible for contraction comes from the myocardial SR, the influx of extracellular calcium through surface membrane channels is also very important for maintaining the sustained "plateau-phase" depolarization of the cardiac action potential. Because extracellular calcium entry is important for initiating cardiac muscle contraction, the strength and speed of cardiac myocyte contraction is proportional to the amount of calcium.

Describe the white pulp

White pulp in the spleen, highlighted here, contains lymphoid aggregations, mostly lymphocytes and macrophages, arranged around the arteries. The lymphocytes consist largely of helper-T cells and antibody-producing B cells.

What are the differences between the human heart and the frog heart in relation to the chambers?

You probably noticed that the frog heart has three chambers instead of four, with two atria but only one ventricle.

Experimental steps for frog dissection

You will distinguish the different phases of the cardiac cycle from these traces To expose the heart, lift and cut away the skin on the ventral side (stomach side) of the frog Lift the abdominal musculature using the forceps and cut a small opening into the abdominal cavity. Insert the blunt end of the scissors into the opening and cut up towards the sternum. Lift the sternum and locate the beating heart beneath it. Remove a small piece of skin from the left thigh of the frog. This allows you to attach the ground wire. Cut away the skin on the right shoulder. This will allow you to place the positive electrode. Force transducer = string and hook; the hook will attach to our frog's heart. Calibrate the transducer using a 5 gram weight. Connect the negative electrode to the hook. This electrode comes out of the red knob. They should be tightly connected. Lift the heart up by its apex and push the hook into the wall of the ventricle. Hook must go through enough of the heart muscle that it will not tear when pulled. Be careful not to go too deep. Adjust the transducer to lift the heart out of the cavity. The tension should be not too tight. Apply ringer solution between the wires and the hook.

Compared to control condition, a blood sample with striped DPG has a(n) _______ P50 and ______ affinity of O2to hemoglobin.

decreased, increased

Several physiologic factors influence hemoglobin behavior, and thus cause shifts in the oxygen-hemoglobin dissociation curve. These factors include:

→ H+ ion concentration (acidity) → Partial pressure of carbon dioxide → Temperature → Diphosphoglycerate, or DPG. We can remember the effects of increases in all these factors with the mnemonic device: "CADET, face right!" C stands for carbon dioxide, A, for acidity, D for diphosphoglycerate, E for exercise (which increases acidity, carbon dioxide, and temperature), and T stands for temperature. An increase in any of these factors causes the oxygen-hemoglobin binding curve to shift to the right. As we have learned, a rightward shift in the curve indicates a lower affinity of hemoglobin for oxygen. Note that decreases in any of these factors would cause a leftward shift in the curve, indicating a higher affinity of hemoglobin for oxygen.

Describe the T cells

→ Helper (CD4) T Cells secrete cytokines that regulate the functions of cells of the immune system. → Cytotoxic (CD8, Killer) T cells directly kill somatic cells infected with viruses and tumor cells.

Describe the B cells

→ Produce circulating antibodies.