Circulation in Mammals and Other Vertebrates

This set of flashcards covers the key concepts regarding the circulatory system, heart functions, muscle physiology, and regulatory mechanisms in mammals and vertebrates.

What are the two circuits of the mammalian heart?

The pulmonary circuit and the systemic circuit.

What is the function of the pulmonary circuit?

Delivers oxygen-poor, CO2-rich blood to lungs and returns oxygen-rich, CO2-poor blood to the body.

What is the function of the systemic circuit?

Delivers oxygen- and nutrient-rich, CO2-poor blood to the body and returns oxygen-poor, CO2-rich blood to the lungs.

What are the main functions of the heart?

Generate blood pressure, route blood, ensure one-way blood flow, and regulate blood supply.

What do chordae tendineae do in the heart?

Connect papillary muscles to the cusps of AV valves, preventing valves from being pushed into the atria.

What is the role of the sinoatrial (SA) node?

It acts as the pacemaker of the heart.

What is the cardiac muscle's unique feature compared to skeletal muscle?

Cardiac muscle cells are branched and have one or two central nuclei.

What is the cardiac cycle?

The repetitive pumping process that begins with the onset of cardiac muscle contraction and ends with the beginning of the next contraction.

What does Starling's Law of the Heart state?

Stroke volume increases as end-diastolic volume increases.

What is the significance of the dicrotic notch?

It is due to elastic recoil of aorta, closure of semilunar valves, and increase in aortic pressure.

What are the effects of aldosterone on the kidneys?

It increases Na+ reabsorption and promotes water retention.

What does an electrocardiogram (ECG) measure?

The summation of all action potentials transmitted by the cardiac muscle cells.

What happens during isovolumetric relaxation?

Ventricular pressure falls, and all valves close.

What is the role of chemoreceptors in blood pressure regulation?

They activate when blood O2 or pH decreases or blood CO2 increases, leading to cardiovascular responses.

What mechanism involves the release of renin from the kidneys?

The Renin-Angiotensin-Aldosterone Mechanism.

Describe the intrinsic regulation of the heart?

It pertains to the heart's normal functional characteristics independent of neural or hormonal influences.

What happens to blood pressure during hemorrhage?

Baroreceptor discharge decreases, leading to increased heart rate and ventricular contractility to restore blood pressure.

What is the effect of increased blood volume on blood pressure?

Increased blood volume raises blood pressure due to larger volume forcing the heart to pump harder.

How does sympathetic stimulation affect cardiac output?

It can increase cardiac output by 50-100% by increasing heart rate and strength of contraction.