19 Questions
Which chamber of the heart expels blood?
Ventricles
Where is the heart located within the thoracic cavity?
In the mediastinum
What is the function of the pericardium in relation to the heart?
Protects the heart from other structures
Which blood vessels always carry blood back to the heart?
Veins
In which layer of the heart is fluid found between it and another layer?
Epicardium
What is the purpose of the septa in the heart?
To divide the chambers of the heart
What is the formula for calculating cardiac output?
CO = SV * HR
What is the normal stroke volume for a 150 lbs. individual?
70 ml
Which nerve is responsible for decreasing heart rate?
Vagus nerve
What does the ejection fraction represent?
Volume of blood pumped out of the heart
How do caffeine and nicotine affect heart rate?
Increase heart rate
Which organ influences heart rate based on emotions and can release cortisol?
Limbic system
Which valves prevent backflow from arteries back into ventricles?
Pulmonary and aortic valves
What is the function of papillary muscles in the heart?
Contract to prevent backflow
Where is the SA node located?
Superior and posterior aspect of right atrium
What does the QRS complex represent in an EKG reading?
Ventricular depolarization
What causes the action potential (electrical current) in cardiac muscle cells?
Na, Ca, and K
Which structure is responsible for holding cardiac muscle cells together?
Intercalated discs
What is the role of conducting cells in the heart?
Establishing cardiac rhythm
Study Notes
Heart Anatomy and Function
- The ventricles are the chambers that expel blood from the heart.
- The heart is located in the thoracic cavity, between the lungs.
Pericardium Function
- The pericardium is a sac that surrounds and protects the heart, reducing friction between the heart and surrounding structures.
Blood Vessels
- Veins are the blood vessels that always carry blood back to the heart.
Heart Layers
- Fluid is found between the visceral pericardium and the epicardium, the innermost and outermost layers of the heart.
Septa Function
- The septa are partitions that separate the heart into left and right sides, ensuring that oxygenated and deoxygenated blood do not mix.
Cardiac Output
- The formula for calculating cardiac output is heart rate (HR) x stroke volume (SV).
- For a 150 lbs. individual, the normal stroke volume is approximately 70 mL.
Heart Rate Regulation
- The vagus nerve is responsible for decreasing heart rate.
- The ejection fraction represents the proportion of blood pumped out of the ventricles with each heartbeat.
Substances Affecting Heart Rate
- Caffeine and nicotine increase heart rate.
Emotional Influence on Heart Rate
- The adrenal gland, which releases cortisol, influences heart rate based on emotions.
Valves
- The semilunar valves prevent backflow from arteries back into ventricles.
Papillary Muscles
- Papillary muscles, located in the ventricles, contract to tighten the chordae tendineae and prevent the cusps of the atrioventricular valves from prolapsing.
SA Node
- The sinoatrial (SA) node, located in the right atrium, is the natural pacemaker of the heart.
EKG Reading
- The QRS complex on an electrocardiogram (EKG) reading represents ventricular contraction.
Action Potential
- The action potential (electrical current) in cardiac muscle cells is caused by the movement of ions across the cell membrane.
Cardiac Muscle Structure
- The intercalated discs are structures that hold cardiac muscle cells together.
Conducting Cells
- Conducting cells in the heart, such as the AV node and bundle of His, transmit electrical signals to coordinate heartbeats.
Test your knowledge on the anatomy and function of the human heart, including details about its location, structure, and pumping capacity. Learn about the pericardium, base, apex, and variations in heart size based on physical activity levels.
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