What portion of the cardiac conduction system serves as a electrical gateway, which allows the atria to contract before the ventricles?

A 55-year-old retired firefighter visits his cardiologist complaining of occasional dizziness and a slow heart rate. His symptoms have worsened over the past few months, especially when exercising. A physical examination reveals a resting heart rate of 45 beats per minute. The cardiologist finds out that the issue causing bradycardia is related to the cardiac pacemaker cells. What ion channel opens FIRST in the pacemaker cells to cause the pre-potential depolarization?

What is the purpose of the entry of calcium into the cardiomyocte in the plateau phase of the cardiomyocyte action potential?

A 68-year-old female visits her doctor after experiencing frequent episodes of palpitations, dizziness, and shortness of breath. She describes a sensation of her heart "fluttering" in her chest. She also mentions occasional fatigue and lightheadedness. A patient care technician performs an EKG and obtains the following results. How would you describe this rhythm?

What is the volume remaining in the ventricles following the ventricular ejection phase during the cardiac cycle?

A BIO-202 student was inspired by Lauren's constant yapping about running (sorry!) and went on a run to calm their anxiety before exam 2. During the run, the student's cardioaccelatory center sent a signal to the SA node to produce a sympathetic response. What receptor is being stimulated, what neurotransmitter binds to that receptor, and what is the change in heart rate?

A 58-year-old presents to the clinic and has been experiencing persistent fatigue and occasional chest discomfort when climbing stairs. He has a history of high cholesterol. During a routine check-up, his doctor notes elevated cholesterol, which resulted in narrowing of the blood vessels due to plaque buildup. How would this affect afterload and contractility?

Which pressure in capillary filtration would increase if an individual has hypertension?

Which hormone(s) work to decrease blood pressure by increasing sodium and water loss from the kidneys?

A 23-year-old alcoholic patient presents to the ER with complaints of fatigue, nausea, vomiting, and yellowing of the skin and eyes, or jaundice. The patient is diagnosed with liver failure and his albumin levels are 1.0 g/dL, which is below the normal range of albumin, at 3.4 to 5.4 g/dL. What would change about the patient's capillary filtration, and would you see edema?

A 25-year-old female was stung by a bee while hiking. Within minutes, she developed redness, swelling, and itching around the sting site. She also noticed that her skin felt warm and slightly swollen in other areas. A doctor explained that her body's immune system had released histamine in response to the sting. What effect does histamine have on the blood vessels?

A 43-year-old male presents to the clinic and states that his legs have been swollen, puffy, and the skin feels very tight around the swollen area. The patient is prescribed a diuretic, which functions to increase water excretion through urination. Additionally, the doctor recommends that the patient should exercise more. Why would exercise be helpful for edema?

Which cells are the antigen-presenting cells? (Select multiple)

In the classical pathway of the complement system, the bacteria is first targeted with antibodies, which stimulates C-proteins to bind. Which of the following is NOT an action of the C3a and C3b proteins?

TRUE OR FALSE: Interferons increase antigen presentation by increasing MCH I expression.

A 12-year-old recently recovered from a viral infection. His doctor explained that a special type of immune cell played a key role in destroying virus-infected cells. These cells recognize infected cells and release toxic molecules to kill them. The doctor mentioned that these immune cells are also known by another name. What the other name for cytotoxic T-cells?

Which antibody is primarily found in granular secretions such as the mucus, semen, and saliva to attack pathogens before they gain access to internal tissues?

Which of the following is an example of active immunity?

TRUE OR FALSE: MCH II present antigens when the cell is infected