The Heart
True or False:
Cardiac muscle has 3x more mitochondria than skeletal muscle.
True
Bo has an end-diastolic volume of 110 mL and an end-systolic volume of 50 mL. What is his stroke volume?
60mL
What is considered a normal systolic blood pressure?
less than/equal to 120mmHg
What gas is primarily transported by hemoglobin?
oxygen
What is the PO2 level in the systemic veins?
100mmHg
Considered the pacemaker of the heart.
What is the Sinoatrial (SA) node.
Represents ventricular depolarization on an ECG.
What is QRS complex.
Average arterial pressure during one cardiac cycle.
What is mean arterial pressure
The volume of air exchanged in one breath.
What is tidal volume.
What respiratory variable increases most significantly during maximal exercise
Respiratory Rate
Describe the path of oxygenated blood flow through the heart.
Blood leaves the lungs, flows through the pulmonary veins into the left atrium. The left atrium contracts and blood flows through the mitral valve and enters the left ventricle. Blood leaves the left ventricle through the aortic valve and enters the aorta. From the aorta blood flows through the systemic arteries, reaching the arterioles, then flowing through the capillaries in systemic tissues throughout the body.
What is the correct sequence of electrical conduction in the heart?
SA node → AV node → Bundle of His → Purkinje fibers
What hormone contributes to increased heart rate?
Epinephrine
What structure allows for gas exchange in the lungs?
Alveoli
Enhanced oxygen unloading due to increased CO₂ and lower pH
What is the Bohr Effect
Describe the path of deoxygenated blood flow through the heart.
Deoxygenated blood enters the heart through the inferior and superior vena cava and flows into the right atrium. From the right atrium, blood passes through the tricuspid valve into the right ventricle. From the right ventricle blood reaches the pulmonary valve and flows through the pulmonary arteries. Pulmonary arteries transport the deoxygenated blood back to the lungs for gas exchange.
An athlete's heart rate is 50 bpm, and their stroke volume is 100 mL/beat. How does their cardiac output compare to an untrained individual with a heart rate of 75 bpm and a stroke volume of 70 mL/beat?
The untrained individual has a slightly higher cardiac output (5250mL/min) compared to the trained athlete (5000 mL/min).However, the athlete's heart is more efficient because they achieve a similar cardiac output with a lower heart rate (50 bpm vs. 75 bpm).
HR x SV
What is cardiac output.
What is the primary driver of gas exchange in the lungs?
partial pressure gradients
What is the primary way that carbon dioxide is transported in the blood
As bicarbonate ions
A main component of the cardiac conduction system that travels along the ventricular septum.
What is AV Bundle (Bundle of His).
During exercise, blood flow is redistributed to meet the demands of active tissues. Explain how blood flow is controlled at both the intrinsic and extrinsic levels.
Intrinsic:
What nervous system slows down heart rate?
Parasympathetic Nervous System (PNS)
What enzyme facilitates the conversion of CO₂ to bicarbonate?
carbonic anhydrase
What adaptation occurs in response to chronic aerobic training?
Increased capillary density