Cardio exam questions
Cardio Exam Questions
Cardio Exam Questions
- How does blood pressure in the arteries compare to blood pressure in the veins?
Blood pressure in the arteries has high pressure as it is carried away from the heart, while in the veins, it is low since the blood is taken to heart from the rest of the body. Therefore, arteries have thick walls, while veins have thin walls.
- Briefly explain why very small organisms can survive without a circulatory system?
Small organisms do not require an elaborate circulatory system as oxygen and carbon dioxide exchange occur directly between the environment and the body tissues. They possess an open circulatory system that contains a hemocoel cavity.
- Briefly explain the mechanism by which positive inotropic agents change cardiac output. Be sure to include how the relevant measures change (ESV or EDV, SV, etc.).
An increase in the concentration of intracellular calcium or sensitivity of receptor proteins to calcium results in positive inotropic agents is increasing myocardial contractility. Cardiac output as a result of positive inotrope can be calculated by multiplying the stroke volume SV, with the heart rate HR, i.e., CO = HR × SV. SV is measured by recording EDV and ESV and subtracting the two, i.e., SV = EDV – ESV
- Where are red blood cells formed in an adult?
Red blood cells are formed in the red bone marrow of the bones of adults. Hemoblasts or stem cells in the red bone marrow provide all components of blood.
- Where are they broken down?
They are broken down in the red bone marrow, where hemoblasts form proerythroblastt cells that develop into red blood cells.
- Imagine blood pressure was too high in the arterioles leading to a capillary bed. Briefly explain how the too high blood pressure would affect capillary exchange.
When there is too much pressure in the capillaries, the capillary exchange would be disrupted, leading to the interference of the movement of substances in and out of the blood vessels. This would lead to the bursting of the capillaries as they are unable to handle the pressure due to the thin walls they have.
- Imagine the delay between the P wave and QRS complex increases. What could this indicate about the electrical system of the heart?
The deflection of the P wave is an indication of right and left atrial depolarization. QRS complex causes depolarization of the right and left ventricular.
- A man has type AB blood and is Rh-positive. What blood types could he receive?
The man can only receive blood from all positive blood types, which include A+, B+, AB+, and O+. The donors must be Rh-positive for their blood to be compatible with that of the man.
- What blood types could he donate to?
He can donate blood to people with only blood group AB+. He is a universal receiver but not a universal donor.
- How does the skeletal muscle pump help with the flow of blood and lymph?
Skeletal muscles contract and relax and thus aid in the flow of blood in the venous. Their rhythmic movements are increased by a person engaging in an exercise.
- Describe the position (open or closed) of all four heart valves just before the end of ventricular systole.
During ventricular systole, the aortic and pulmonic valves are open to allow blood to flow into the aorta and the pulmonary artery. The atrioventricular valves are closed so that blood does not flow back into the ventricles.
- Similarly, describe the position of the valves just before the end of the ventricular diastole.
The aortic and pulmonary valves are closed in the ventricular diastole. The atrioventricular valves are opened for blood to be pumped into the ventricles.
- Briefly describe the mechanism by which the baroreceptors reflex prevents orthostatic hypotension when you go from lying down to standing up.
When you stand up, the baroreceptor reflexes are quickly activated to bring back the arterial pressure. When standing, the arterial pressure is maintained by increasing the systemic vascular resistance and heart rate while decreasing stroke volume and venous compliance. This helps to prevent orthostatic hypotension.
- Describe the role of prothrombinase in the coagulation phase of hemostasis.
Prothrombin is a Vitamin-K dependent coagulating element that is activated proteolytically to release thrombin. Thrombin acts as a serine protease that converts fibrinogen into fibrin, which aids in coagulation through platelets and other factors.
- How does a lymphatic capillary differ from a continuous capillary?
The lymphatic capillaries are slightly bigger than continuous capillaries. They have close ends, while blood capillaries have loop structures. They only allow an inward flow of interstitial fluids. Lymphatic capillaries have their endothelial cells on the walls overlapping, unlike the continuous capillaries.
- How does blood flow velocity in a large artery compare with that in a large vein?
In large arteries, blood is under high velocity as it is being pumped by the heart to reach all parts of the body. In the veins, the velocity is slowed by capillaries during the exchange and thus flows slowly back to the heart.
- Briefly describe what happens to the iron in hemoglobin when a red blood cell is broken down.
When a red blood cell is broken down, the iron in it is collected by protein transferrin and taken to the bone marrow. In the bone marrow, the iron is reused for the production of new red blood cells.
- Why is the SA node the pacemaker of the heart?
Cells in the SA node are able to naturally generate electric impulses. The continuous generation of the electric impulses helps in the formation of a normal rhythm of the heart at a constant rate when healthy. This is why the SA node is referred to as the pacemaker of the heart.
- Why not a location within the ventricles?
This is because the ventricles in the heart are not used in the pumping of blood as all the work of contraction and expansion is found in the articles. The sinoatrial node is located in the right atrium, where it produces electric impulses to aid in the pumping of blood.
- Cardiac tamponade occurs when fluid and pressure build up in the pericardial cavity. Briefly explain how cardiac tamponade would affect end-diastolic volume.
Cardiac tamponade would result in decreasing cardiac output. This is due to a decrease in the return flow in the venous, and the diastolic volume in the chambers is reduced.
- Briefly describe the structure of a red blood cell.
The red blood cells or erythrocytes have a disk-shape/biconcave appearance. They are circular with a thin center and thick periphery.
- How does this structure help the red blood cell with its function?
The biconcave shape helps erythrocytes in creating more space for hemoglobin molecules, which are used in the transportation of gases in the body. The shape also helps in increasing the surface area for gas exchange.
- Briefly compare and contrast the properties of monocytes and neutrophils.
Bothe monocytes and neutrophils are phagocytes. They are essential in fighting diseases. When they get into tissues, they can be turned into macrophages, which eat things. In contrast, neutrophils are phagocytes and not antigens, while monocytes act as antigens. Neutrophils have a busy nucleus and granules, while monocytes have a horseshoe-shape nucleus and greyish cytoplasm.
- Briefly describe the mechanism of platelet plug formation.
Platelet plug formation happens before fibrin mesh for clotting is created but after vasoconstriction of blood vessels. It causes blood to coagulate when there is an injury resulting in a clot.
- Briefly explain why the heart can’t normally undergo a tetanic contraction, while skeletal muscle can.
This is because the heart is made of cardiac muscles whose cell membrane is different from that of skeletal muscle fiber. The cardiac muscles are unable to undergo tetanic contraction, and this is advantageous to the heart to keep it pumping blood.
- Briefly explain why vessel diameter is a better mechanism for controlling blood pressure than vessel length.
Vessel diameter helps in controlling blood pressure, where it increases pressure as it decreases in size. In the capillaries, there is more pressure to increase exchange. An increase in length only lowers pressure
- How is the structure and function of the spleen similar to that of a lymph node?
The spleen filters old blood cells from the blood similarly to how the lymph node filters the lymph. Structurally, the spleen is like a giant lymph node but contains only the efferent lymph vessels.
- Briefly describe the flow of lymph through a lymph node.
The lymph enters the lymph node via the afferent vessels. This is taken through the cortex, paracortex, and the medulla of the lymph node before exiting on the other side through the efferent vessels. There are more afferent lymphatic vessels entering the lymph nodes than the efferent lymphatic vessels leaving.