The Platelet Quiz

Platelets

• Platelets are associated with characteristics such as small size, anucleate, and short lifespan.
• The main role of platelets in hemostasis is to form a platelet plug to stop bleeding.

Cardiac Cycle

• The two major events in the cardiac cycle are diastole and systole.
• The phase of the cardiac cycle characterized by the contraction of the atria and the opening of AV valves is atrial systole.
• During atrial systole, SL valves prevent backflow of blood into the atria.
• Isovolumetric ventricular contraction occurs in the cardiac cycle when the ventricles contract and the AV valves are closed.
• There are 8 phases or steps in the cardiac cycle.

ECG and Cardiac Output

• The QRS complex in the ECG coincides with the onset of ventricular systole.
• The main purpose of measuring blood flow, pressure changes, and blood volume throughout the phases of the cardiac cycle is to evaluate cardiac function.
• Cardiac output can be calculated using the formula: CO = HR x SV.

Heart Structure and Function

• The autonomic nervous system relays information derived from blood pressure through the medulla oblongata.
• The outermost layer of the heart wall is the epicardium.
• The AV valves ensure blood flows from the atria to the ventricles and prevent backflow.
• The SL valves prevent backflow of blood into the atria during ventricular systole.

Blood Pressure Regulation

• The law of Starling states that the longer or more stretched the heart fibers are at the beginning of contraction, the stronger the contraction.
• Baroreceptors are located in the walls of arteries and veins.
• The term for the amount of blood left in the ventricles after ejection is end-systolic volume.
• The term for the phase of ventricular diastole between the closure of the SL valves and the re-opening of the AV valves is diastasis.

Heart Layers

• The endothelium makes up the innermost layer of the heart wall.
• The endothelium lines the heart chambers and blood vessels.

Test your knowledge on thrombocytes and their role in hemostasis with this quiz. Learn about the characteristics and functions of platelets, including agglutination, adhesiveness, and aggregation. Gain a deeper understanding of how platelets help reduce bleeding from injured vessels.