Human Body: BMI And ECG Quiz

Depolarization is the correct answer because the influx of Na+ ions causes a change in the electrical charge across the membrane, making it more positive. This change in charge is the first phase of the action potential, where the membrane potential becomes less negative or even positive.

In electrical terms, "potential" refers to the amount of electrical energy that a charged object possesses. This is commonly known as voltage. Voltage is a measure of the electric potential difference between two points in an electrical circuit, indicating the force that drives electric current to flow. Therefore, the correct answer is voltage.

The resting membrane potential of a neuron refers to the electrical charge difference across its cell membrane when it is not actively transmitting signals. This potential is typically around -70mV, which means that the inside of the neuron is negatively charged compared to the outside. This negative charge is maintained by the balance of ions, with more negatively charged ions inside the neuron and more positively charged ions outside. This potential is essential for the proper functioning of neurons and allows them to transmit electrical signals when stimulated.

The Na/K pump operates by transporting three sodium ions out of the cell while transporting two potassium ions into the cell. This process is essential for maintaining the cell's electrochemical gradient and regulating cell volume. By actively pumping sodium out and potassium in, the Na/K pump helps to establish a negative charge inside the cell and a positive charge outside. This is crucial for various cellular processes such as nerve impulse transmission and muscle contraction.

The T wave on an ECG represents ventricular repolarization. This means that the ventricles of the heart are relaxing and preparing for the next contraction. During ventricular repolarization, the electrical activity in the ventricles is resetting, allowing them to refill with blood and prepare for the next heartbeat. This is an important phase in the cardiac cycle and is represented by the T wave on an ECG.

Curare is a toxin that blocks the acetylcholine receptors on muscle tissue. Acetylcholine is a neurotransmitter that is responsible for transmitting signals from motor nerves to muscle fibers. By blocking these receptors, curare prevents the muscle from receiving the signal to contract, leading to an inability of the muscle to respond to motor nerve stimulus. This would result in muscle paralysis or a loss of muscle function.

The left atrium receives oxygenated blood from the lungs through the pulmonary veins. It is responsible for pumping this oxygenated blood into the left ventricle, which then pumps it out to the rest of the body. The mitral valve is located between the left atrium and left ventricle, ensuring that blood flows in one direction. The right ventricle receives deoxygenated blood from the right atrium and pumps it to the lungs for oxygenation. The vena cava is a large vein that carries deoxygenated blood from the body back to the right atrium of the heart.

When a valve is damaged by rheumatic fever, it can become stiff and narrowed, leading to a partial opening. This condition is known as stenosis. Stenosis restricts the flow of blood through the valve, causing various symptoms depending on the affected valve. Heart block refers to a disruption in the electrical signals that control the heart's rhythm. MI (myocardial infarction) is the medical term for a heart attack, which occurs when blood flow to the heart muscle is blocked. Fibrillation refers to abnormal, rapid, and chaotic contractions of the heart muscles.

Resting neuronal membranes have a higher concentration of sodium ions on their outer surface compared to the inner surface. This is because the resting membrane potential is maintained by the sodium-potassium pump, which actively transports sodium ions out of the neuron and potassium ions into the neuron. As a result, there is a higher concentration of sodium ions outside the neuron, leading to a greater accumulation on the outer surface of the membrane.

Skeletal muscles are responsible for the voluntary movements of the body, including eye movements. The muscles that control the movement of the eyes are skeletal muscles, allowing us to move our eyes in different directions, track objects, and focus on specific points. Constriction of blood vessels, heartbeat, and dilation of the pupil are controlled by smooth muscles, not skeletal muscles.

The sarcomere is the smallest contractile unit of skeletal muscle. It is responsible for the contraction and relaxation of the muscle fibers. It consists of overlapping thick and thin filaments, which slide past each other during muscle contraction, causing the sarcomere to shorten. The motor unit refers to a motor neuron and the muscle fibers it innervates, while the synapse is the junction between two nerve cells. Thin filaments are one of the components of the sarcomere, but they alone do not constitute the smallest contractile unit.

The correct answer is mediastinum. The mediastinum is the space in the middle of the thoracic cavity where the heart resides. It is located between the lungs and extends from the sternum to the vertebral column. It contains various structures including the heart, great vessels, esophagus, trachea, thymus, and lymph nodes. The pericardial cavity is the space within the mediastinum that contains the heart. The pericardium is a double-layered sac that surrounds the heart. The dorsal cavity refers to the posterior cavity of the body, which includes the cranial cavity and spinal cavity.

During ventricular systole, the AV valves are closed. This is because the ventricles are contracting, causing the pressure inside the ventricles to increase. As a result, the AV valves, which are located between the atria and ventricles, close to prevent the backflow of blood into the atria. This closure ensures that blood is forced out of the ventricles and into the arteries, allowing for efficient blood circulation throughout the body.

Arterioles are the smallest branches of arteries that regulate blood flow and blood pressure. They have smooth muscle in their walls, which allows them to constrict or dilate, controlling the amount of blood that flows into capillaries. This constriction and dilation help regulate blood pressure and direct blood flow to specific tissues based on their needs. Therefore, arterioles play a crucial role in the regulation of blood flow to a tissue and blood pressure.

If there is a blockage between the AV node and AV bundle, it means that the electrical signals from the atria are not being properly conducted to the ventricles. This would result in an increased number of P waves compared to QRS complexes on the ECG. The P wave represents atrial depolarization, while the QRS complex represents ventricular depolarization. Since the electrical signals are not reaching the ventricles as efficiently, there would be a delay in the ventricular depolarization, leading to a higher number of P waves than QRS complexes.

When communication between the SA node and the AV node becomes blocked, the electrical signals that initiate the contraction of the ventricles are disrupted. As a result, the ventricles will contract at a slower rate. The SA node is responsible for initiating the electrical impulses that regulate the heart rate, while the AV node helps to coordinate the timing of the electrical signals between the atria and ventricles. Therefore, if the communication between these two nodes is blocked, it will primarily affect the ventricles' contraction rate.