Red Alert!
This type of blood cell is responsible for carrying oxygen throughout the body.
What is a red blood cell?
This chamber of the heart receives oxygen-poor blood from the systemic circulation.
What is the right atrium?
These specialized cardiac cells initiate the heartbeat by generating spontaneous action potentials.
What are pacemaker cells?
Draw the flow of blood through the heart, starting from the vena cava and ending at the aorta.
Right atrium → tricuspid valve → right ventricle → pulmonary valve → lungs → pulmonary veins → left atrium → mitral valve → left ventricle → aortic valve → aorta
Unlike cardiac muscle, this type of muscle requires direct neural stimulation to initiate contraction.
What is skeletal muscle?
These white blood cells are the most abundant and are the first responders to bacterial infection
What are neutrophils?
These semilunar valves prevent backflow of blood into the ventricles after contraction.
These semilunar valves prevent backflow of blood into the ventricles after contraction.
This node, located in the right atrium, is the primary pacemaker of the heart.
What is the sinoatrial (SA) node?
Sketch the QRS complex on an ECG and label what it represents.
ventricular depolarization
Unlike skeletal muscle, cardiac muscle cells are connected by these specialized junctions that allow electrical continuity.
What are intercalated discs?
This glycoprotein hormone, produced primarily by the kidneys, stimulates red blood cell production.
This glycoprotein hormone, produced primarily by the kidneys, stimulates red blood cell production.
This wave on an ECG represents ventricular depolarization.
What is the QRS complex?
In pacemaker cells, this ion is primarily responsible for the depolarization phase.
What is calcium?
Draw the conduction system of the heart and label each major component.
SA node, AV node, bundle of His, right and left bundle branches, Purkinje fibers
This part of the brain coordinates voluntary motor activity and fine-tunes movement initiated by the motor cortex.
What is the cerebellum?
This structural feature of red blood cells increases surface area for gas exchange and allows flexibility in capillaries.
What is a biconcave shape?
This phase of the cardiac cycle accounts for most ventricular filling and occurs before atrial contraction.
What is passive filling?
During this phase of the cardiac action potential, no new action potential can be initiated, regardless of stimulus strength.
What is the absolute refractory period?
Draw and label the phases of the cardiac action potential in a contractile cell.
Phases 0–4, ion movements (Na⁺, Ca²⁺, K⁺)
This ion is essential for both cardiac and skeletal muscle contraction and is released from the sarcoplasmic reticulum.
What is calcium?
This rare genetic disorder affects clotting factor VIII and leads to prolonged bleeding.
What is hemophilia?
This phase of the cardiac cycle occurs when the ventricles contract and eject blood into the arteries.
What is ventricular systole?
Unlike pacemaker cells, contractile cells have this resting membrane potential, allowing rapid depolarization when stimulated.
What is −90 millivolts?
Draw the action potential of a pacemaker cell and label the key phases and ion channels involved.
Phases: slow depolarization (Na⁺ current), rapid depolarization (Ca²⁺), repolarization (K⁺); no stable resting potential
This division of the nervous system regulates involuntary functions such as heart rate and digestion.
What is the autonomic nervous system?