Chapter 9 Circulatory System Flashcards
(31 cards)
What are the primary purposes of the cardiorespiratory system?
- Deliver oxygen to body tissues
- Remove waste from tissues
- Transport nutrients
- Aid in temperature regulation
These functions are essential for maintaining homeostasis and supporting cellular metabolism.
What are the four chambers of the heart?
- Right Atrium
- Left Atrium
- Right Ventricle
- Left Ventricle
Each chamber plays a specific role in the circulation of blood through the body.
What are the two circuits of the heart?
- Pulmonary circuit: Heart → Lungs (right side of heart)
- Systemic circuit: Heart → Rest of body (left side of heart)
The pulmonary circuit is responsible for oxygenating blood, while the systemic circuit delivers oxygenated blood to the body.
What are the three layers of heart tissue?
- Epicardium: Lubricative outer coating
- Myocardium: Provides muscular contraction
- Endocardium: Protective lining of chambers and valves
Each layer has distinct functions that contribute to the overall performance of the heart.
What are the properties of cardiac muscle?
- Muscle fibers are short and branched
- Highly aerobic with many mitochondria
- Contraction is involuntary
- Fibers connected via intercalated disks (transmit electrical signals)
These properties enable the heart to function effectively and continuously.
What are the phases of the cardiac cycle?
- Systole: Contraction phase
- Diastole: Relaxation phase
These phases allow for the efficient pumping of blood through the heart and into the circulatory system.
What is the role of the AV valves and semilunar valves?
- AV Valves: Separate atria and ventricles
- Semilunar Valves: Pulmonary and aortic valves
These valves prevent backflow of blood and ensure unidirectional flow through the heart.
Describe the blood pressure sequence during the cardiac cycle.
- Low pressure in ventricles during atria filling
- Slight pressure increase when atria contract
- Sharp pressure rise when ventricles contract
- AV valves close to prevent backflow
- Semilunar valves open when ventricular pressure exceeds aortic/pulmonary artery pressure
This sequence is critical for maintaining effective circulation.
What is the function of the SA Node?
Generates electrical impulse; known as the ‘Pacemaker of the heart’
The SA node initiates the heartbeat and sets the pace for the entire cardiac cycle.
What does the ECG record?
Records electrical changes during the cardiac cycle
ECG is a vital tool for diagnosing heart conditions and monitoring heart health.
What are the components of an ECG?
- P Wave: Atrial depolarization
- QRS Complex: Ventricular depolarization
- T Wave: Ventricular repolarization
Each component represents a specific electrical activity occurring in the heart.
What is the normal resting heart rate range?
60-80 bpm
Deviations from this range can indicate potential health issues.
What is tachycardia?
Heart rate >100 bpm
This condition can arise from various physiological and pathological factors.
What is bradycardia?
Heart rate <60 bpm
This condition may require medical evaluation if symptomatic.
What is Heart Rate Variability (HRV)?
Variation in time between beats
Higher HRV is generally associated with better cardiovascular health.
What is Cardiac Output (Q)?
Volume of blood pumped per minute
It is a critical parameter for assessing cardiac function.
What is the formula for calculating Cardiac Output?
Q = Heart Rate × Stroke Volume
This relationship helps in understanding how the heart meets the body’s demands.
What are the factors that can increase cardiac output?
- Increasing heart rate
- Increasing stroke volume
- Increasing both
Each factor contributes to enhancing the heart’s performance during physical activity.
What is the role of the parasympathetic nervous system in heart rate regulation?
Slows HR by inhibiting SA and AV nodes
The parasympathetic system is associated with ‘rest and digest’ activities.
Which neurotransmitter is involved in parasympathetic heart rate regulation?
Acetylcholine
This neurotransmitter plays a key role in reducing heart rate.
What is the role of the sympathetic nervous system in heart rate regulation?
Increases HR by stimulating SA and AV nodes
This system is associated with ‘fight or flight’ responses.
Which neurotransmitter is involved in sympathetic heart rate regulation?
Norepinephrine
Norepinephrine increases heart rate and cardiac contractility.
What is End-Diastolic Volume (EDV)?
Volume of blood in the ventricles at the end of diastole
Greater EDV leads to more forceful contractions due to the Frank-Starling Mechanism.
