Exam 3 | Cardiovascular 2

Question 1

Is the heart able to beat without stimulation from the nervous system?

Answer 1

Yes! Due to the presence of two independent nodes which include electrically-excitable cells (not neurons) that stimulate rhythmic muscle contractions.

Question 2

Describe the sequence of events that allows the heart to beat without input from the nervous system.

Answer 2

Cells that comprise the Sinoatrial (SA) Node, located in the anterior portion of the right atrium, initiate cardiac muscle contraction. These cells serve as the heart’s natural pacemaker. The electrical signal from the SA node passes through the endocardial lining to the left atrium, causing both atria to contract simultaneously.

Then, cells that comprise the Atrioventricular (AV) Node, located at the base of the right atrium, triggers simultaneous contraction of the left and right ventricles after the atria have relaxed. Purkinje Fibers in the myocardial lining help to relay the electrical signal from the AV node to both ventricles.

Question 3

What are the 2 nodes that allow the heart to pump without the nervous system?

Answer 3

Sinoatrial (SA) Node & Atrioventricular (AV) Node

Question 4

What is the purpose of electrocardiography?

Answer 4

This noninvasive technique for indirectly measuring electrical activity in the heart allows clinicians to visualize the electrical waves produced from heart contractions, and detect obvious abnormalities in this electrical activity, including arrhythmias.

Question 5

What is the PQRST wave found from electrocardiography?

Answer 5

The PQRST wave represents electrical activity of the heart

Question 6

Describe each point on a PQRST wave.

Answer 6

There’s the P-wave, PR interval, QRS complex, ST segment, and T-wave

Question 7

What does the P wave represent?

Answer 7

The P-wave corresponds to the initial depolarization of the right atrium in response to electrical activity from the SA Node.

Question 8

What does the PR interval represent?

Answer 8

The PR interval corresponds to the delay in electrical activity in the AV Node as the ventricles remain relaxed, allowing them to fill with blood received from the contraction of the atria.

Question 9

What does the QRS complex represent?

Answer 9

The QRS complex corresponds to the depolarization of the right ventricle in response to electrical activity from the AV Node.

Question 10

What does the ST segment represent?

Answer 10

The ST segment corresponds to the gradual repolarization of the ventricles as they begin to relax after contracting in the QRS complex.

Question 11

What does the T-wave represent?

Answer 11

The T-wave corresponds to the final stage of ventricular repolarization, allowing the ventricles to completely refill with blood.

Question 12

What are the 3 types of blood vessels?

Answer 12

arteries, veins, capillaries

Question 13

What’s the function of arteries?

Answer 13

The arteries are turgid (stiff) blood vessels that circulate blood away from the heart. They are pressurized and thus, blood pressure measurements correspond to the pressure of blood flowing through the arteries at any given moment in time.

Question 14

What’s the function of veins?

Answer 14

The veins are flaccid (loose) blood vessels that return blood to the heart from the rest of the body and lungs. They contain valves that prevent backwards flow of blood

Question 15

What’s the function of capillaries?

Answer 15

The capillaries are the smallest of the three types of blood vessels, and are far more abundant than arteries and veins. They participate directly in the process of gas exchange (i.e. exchanging oxygen for carbon dioxide) due to their relatively thin outer membrane that permits simple diffusion of these gases across the capillary walls.

Question 16

From superficial to deep, describe the 3 cell layers protecting arteries and veins.

Answer 16

Simple connective tissue serves as the outer physical barrier between the external environment and the internal blood in the vessels.

Smooth muscle and elastic connective tissue both comprise the middle layers of arteries and veins.

Epithelial tissue known as the endothelium makes up the inner lining of arteries and veins.

Question 17

What are capillaries made up of?

Answer 17

single layer of endothelial cells

Question 18

Where does bulk flow occur?

Answer 18

In capillaries because they only have 1 layer

Question 19

What is bulk flow?

Answer 19

the dual processes of filtration and resorption of nutrients between the systemic tissues and the internal fluid (blood) in the capillaries.

Question 20

Where does filtration occur and how is blood pressure impacted?

Answer 20

Filtration occurs at the arteriole end of the capillary: high blood pressure at this end forces water to exit the capillaries and enter the tissues, leaving large blood proteins in the capillary as they are not capable of diffusing across the capillary wall. Thus, blood pressure is greater than osmotic pressure at this end.

Question 21

Where does resorption occur and how is blood pressure impacted?

Answer 21

Resorption occurs at the venule end of the capillary: as blood continues to flow through the capillary, the blood pressure gradually decreases towards this end and osmotic pressure increases, causing water (and other small nutrients/ molecules) to be reabsorbed back into the capillary. Thus, osmotic pressure is greater than blood pressure at this end.

Question 22

What is atherosclerosis?

Answer 22

Atherosclerosis is a condition in which build-up of fats, cholesterol or other substances can form plaques along the inner walls of the arteries and cause obstructions to blood flow.

Question 23

What does atherosclerosis cause?

Answer 23

Most commonly, this condition can result in high blood pressure (hypertension), but in more severe cases, it can lead to the formation of blood clots and another general condition known as thrombosis.

Question 24

What is blood made up of?

Answer 24

Blood is composed of a purely liquid portion known as plasma, and a more dense solid portion of formed elements, which are mainly cells.

Question 25

How does blood maintain homeostasis?

Answer 25

Aiding in the formation of clots to prevent severe blood loss after injury.

Specific blood cells “monitor” the body for pathogens (i.e. leukocytes).

The plasma contains hormones and other important chemicals (including gases) that need to be transported throughout the body.

Blood also plays a role in insulation and thermoregulation by transferring heat throughout the body.

Question 26

What is plasma made of and how much of it makes up blood volume?

Answer 26

Plasma makes up roughly 40 - 70% of total blood volume, and is 92% water, 7% dissolved proteins and 1% electrolytes, nutrients and wastes.

Question 27

What are blood proteins?

Answer 27

Blood proteins, specifically albumin, help to maintain the osmolarity of the blood and also regulate the osmotic pressure in the blood vessels so that blood remains an isotonic solution

Question 28

What electrolytes are found in blood plasma?

Answer 28

The most abundant electrolytes in blood plasma are sodium, potassium and calcium

Question 29

What macromolecules can you find in blood?

Answer 29

Other chemicals found in the blood include macromolecules like carbohydrates and amino acids

Question 30

How is water helpful in the plasma?

Answer 30

Water in the plasma also dissolves toxins such as urea, lactic acid and carbon dioxide, diluting them to maintain a specific blood pH of roughly 7.4

Question 31

Where do all blood cells originate?

Answer 31

All blood cells originate from a common cellular ancestor, known as a multipotent hematopoietic stem cell (or hemocytoblast), which forms in the red blood marrow

Question 32

What is the name of the process for creating new blood cells?

Answer 32

Hematopoiesis.

Question 33

What are the majority of blood cells? What’s the minority?

Answer 33

99% of these blood cells are erythrocytes (red blood cells), and roughly 0.1% are leukocytes (white blood cells)

Question 34

What are the smallest cells in the body?

Answer 34

Red Blood Cells (RBCs) are some of the smallest cells in the body, and do not have a nucleus (or very many other membrane-bound organelles). Thus, they are essentially membrane-bound “sacs” that carry a specialized protein known as hemoglobin.

Question 35

What are the purpose for RBC?

Answer 35

Each RBC carries about 200 million hemoglobin molecules, each of which contain four hemes, which are the tertiary structure of the hemoglobin protein. As more hemes are occupied with oxygen, the binding affinity of the hemoglobin molecule for oxygen increases.

The RBCs will travel through the body via the three types of blood vessels discussed earlier in this lecture, and will release oxygen from the four hemes in tissues where oxygen levels are low. Likewise, hemoglobin will bind more oxygen on its four hemes in tissues where oxygen levels are high.

Question 36

Where do RBC come from?

Answer 36

RBCs originate from a specific type of progenitor cell, known as a reticulocyte (essentially an “immature” RBC).

Question 37

What happens to mature/damaged RBC?

Answer 37

Because they lack nuclei, they are incapable of repairing themselves when they are damaged. Thus, mature RBCs typically have a short lifespan and circulate for 120 days before being removed and recycled by the spleen and liver. Roughly 2 million RBCs are destroyed per second

Question 38

What are the different blood types and what’s their corresponding antigen?

Answer 38

Individuals with Type A blood express only the A antigen on their RBCs

Individuals with Type B blood express only the B antigen on their RBCs

Individuals with Type AB blood express both the A and B antigens on their RBCs

Individuals with Type O blood do not express any antigens on their RBCs; universal donor because their blood can be easily transfused into another individual regardless of their blood type, as it will not cause an immune response from the recipient’s immune system

Question 39

What are agglutinins?

Answer 39

Antibodies that will attack surface antigens on RBC’s of a different blood type

Question 40

What happens when different blood types is mix?

Answer 40

If an individual has Type A blood, their blood will also contain antibodies against the B antigen: binding to a B antigen would cause clotting, also known as coagulation.

Question 41

What is a Rh factor?

Answer 41

The rhesus (Rh) factor is a protein that is either present (Rh+) or absent (Rh-) on the surface of RBCs.

Question 42

How do Rh factors complicate pregnancy?

Answer 42

When the Rh protein is present in the fetus’s blood but not in the mother’s, causing the mother to build up antibodies. If these enter the fetus’s system, they destroy red blood cells, reducing the oxygen supply to organs and tissues.

Question 43

What are blood thinners?

Answer 43

Blood thinners are a class of drugs prescribed in patients at risk of blood clotting (which can lead to more serious problems, including heart attacks and strokes).

Question 44

What are common prescribed blood thinners?

Answer 44

Warfarin and certain doses of over-the-counter aspirin can function as blood thinners, and have historically been recommended for daily intake in patients who have suffered heart attacks

Question 45

What’s a common example of a blood disorder?

Answer 45

Anemia which affects the RBC and ranging in severity from common forms that often result from low iron levels in the blood to more severe disorders such as sickle cell anemia.

Question 46

What is sickle cell anemia?

Answer 46

Sickle Cell Anemia is a genetic disorder caused by a single point mutation that causes the improper formation of the hemoglobin protein, ultimately resulting in a characteristic sickle shape of the RBCs and a reduction in their ability to bind and carry oxygen. Individuals with sickle cell anemia are often more prone to illnesses and are limited in their cardiac activity due to poor oxygen circulation throughout the body.

Question 47

What is congestive heart failure?

Answer 47

Congestive Heart Failure is an anatomical cardiovascular disease (CVD) caused by a generally weak heart that struggles with adequately pumping blood to the lungs and body, causing blood to accumulate, or pool, in the lungs/ thoracic cavity.

Question 48

What symptoms for CVD?

Answer 48

Fatigue

Shortness of breath (or general difficulty breathing)

Tachycardia (abnormally rapid resting heart rate)

Question 49

How can CVD be treated?

Answer 49

If left untreated, congestive heart failure can quickly become deadly (typically as a result of fluid accumulation in the lungs).

If detected in the early stages, treatments for congestive heart failure can include the following:

Changes to diet and exercise routines (most often reducing salt intake)

Prescription medications such as angiotensin-converting enzyme (ACE) inhibitors

Surgical interventions, including pacemaker implantation to control heart rhythm

In severe cases, heart transplantation may be necessary

Question 50

What is a myocardial infarction?

Answer 50

A heart attack (also known as a myocardial infarct), loss of oxygen causes damage (or necrosis) of the myocardial tissue. This lack of oxygen and subsequent necrosis of the myocardium often results from an arterial blockage, compromising the normal heart rhythm

Question 51

What are the signs of a heart attack?

Answer 51

Chest pain/ discomfort, particularly in the left shoulder area

Shortness of breath/ difficulty breathing

Feeling nauseous or light-headed

Sudden fatigue

Question 52

What should you do if someone is having a heart attack?

Answer 52

If you or someone you know is having a heart attack, you should immediately call 9-1-1, and in the meantime, chewing aspirin can help to cause immediate blood thinning and reduce the potential for further arterial blockage. After someone has suffered a heart attack (or stroke), they are often prescribed a blood thinner (such as warfarin) to reduce the risk of future heart attacks.

Question 53

What are strokes?

Answer 53

Strokes can be the result of a blood clot that cuts off blood flow (and thus, reduces oxygen availability) to the brain, or the result of a vessel burst that lead to bleeding in the brain (often observed in the case of brain aneurysms). Regardless, the end result is permanent tissue loss/ damage in the brain that can lead to a wide variety of cognitive and other neurological impairments.

Question 54

What are the different types of strokes?

Answer 54

Ischemic Stroke, which occurs when an arterial blockage cuts of blood flow (and thus, oxygen) to the brain, leading to necrosis of brain tissue.

Hemorrhagic Stroke, which occurs when an artery bursts, causing excessive bleeding (and ultimately, tissue damage) in the brain.

Transient Ischemic Attack (TIA) is the least severe of the three types of strokes, and is sometimes referred to as a “baby stroke” because of the local nature of the (usually small) arterial blockage (typically not affecting one of the major arteries supplying the brain).

Question 55

What are the signs of a stroke?

Answer 55

Sudden body weakness or facial drooping (usually hemilateral, or on one side)

Trouble speaking and/ or difficulty understanding speech

Sudden vision and/ or motor impairments

Question 56

What typically happens if someone suffers from a stroke?

Answer 56

Neuroimaging (CT/CAT scans and MRI) are used to accurately treat the stroke.

As with heart attacks, patients who have suffered a stroke are typically prescribed a blood thinner like warfarin to reduce the risk of a future stroke.

Question 57

What’s angia?

Answer 57

Angina occurs when the heart muscle is temporarily deprived of oxygen, causing a radiating pain and a “cramping” of the heart muscle

Question 58

What are the 3 forms of angia?

Answer 58

Stable Angina is commonly caused by atherosclerosis in the peripheral (coronary) arteries.

Unstable Angina is similar to stable angina, however, the formation of a blood clot as a result of atherosclerosis distinguishes this form from stable angina.

Variant (Transient) Angina can occur when there are spasms of the coronary arteries, briefly disrupting blood flow and oxygen supply to the heart.