How is a heartbeat maintained?

Heart rate is controlled by the two branches of the autonomic (involuntary) nervous system. The sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS). The sympathetic nervous system (SNS) releases the hormones (catecholamines – epinephrine and norepinephrine) to accelerate the heart rate.

How is a heartbeat initiated in the heart quizlet?

The heart beat is initiated by a group of specialized muscle cells in the right atrium called the sinoatrial node, which acts as a pacemaker. The sinoatrial node sends out an electrical signal that stimulates contraction as it is propagated through the walls of the atria and then the walls of the ventricle.

How is heartbeat produced?

The impulse starts in a small bundle of specialized cells located in the right atrium, called the SA node. The electrical activity spreads through the walls of the atria and causes them to contract. This forces blood into the ventricles. The SA node sets the rate and rhythm of your heartbeat.

How is heartbeat regulated quizlet?

Changes in the heartbeat are controlled by the autonomic nervous system, specifically the cardiac control center in the medulla oblongata. In times of stress or exercise, the cardiac control centre sends sympathetic nerve signals to increase cardiac output.

What regulates the rate and force of heart contractions quizlet?

the autonomic nervous system affects the rate and force of heart contractions. The autonomic nervous system is regulated by the hypothalamus. The sympathetic nervous system has control on and releases the hormones such as catecholamines, epinephrine and norepinephrine to accelerate the heart rate.

Which part of the brain regulates heartbeat?

The brain stem sits beneath your cerebrum in front of your cerebellum. It connects the brain to the spinal cord and controls automatic functions such as breathing, digestion, heart rate and blood pressure.

How is the heart made up?

The heart is made of three layers of tissue. Endocardium, the thin inner lining of the heart chambers that also forms the surface of the valves. Myocardium, the thick middle layer of muscle that allows your heart chambers to contract and relax to pump blood to your body. Pericardium, the sac that surrounds your heart.

What are the 4 main functions of the heart?

The four main functions of the heart are:

• Pumping oxygenated blood to the other body parts.
• Pumping hormones and other vital substances to different parts of the body.
• Receiving deoxygenated blood and carrying metabolic waste products from the body and pumping it to the lungs for oxygenation.
• Maintaining blood pressure.

How does the heartbeat quizlet?

The specialized sinoatrial node (SA node) is located on the upper inside wall of the right atrium. The SA node is the pacemaker of the heart, and it initiates a heartbeat every 0.85 seconds. This signal travels across the atria, causing them to contract and load the ventricles with blood.

What are the main structures of the heart include the structures that regulate the heartbeat in your answer quizlet?

The heartbeat happens as follows:

• The SA node (called the pacemaker of the heart) sends out an electrical impulse.
• The upper heart chambers (atria) contract.
• The AV node sends an impulse into the ventricles.
• The lower heart chambers (ventricles) contract or pump.

What regulates the rate and force of heart contractions?