A&P Chapter 18-19 Flashcards

Questions and Answers

Which of the following statements is correct about cardiac output?

If a semilunar valve were partially obstructed, the end systolic volume in the affected ventricle would be decreased.

A slow heart rate increases end diastolic volume, stroke volume, and force of contraction. (correct)

Stroke volume increases if end diastolic volume decreases.

Decreased venous return will result in increased end diastolic volume.

During contraction of heart muscle cells, which statement is true?

Calcium is prevented from entering cardiac fibers that have been stimulated.

Some calcium enters the cell from the extracellular space and triggers the release of larger amounts of calcium from intracellular stores. (correct)

The action potential is initiated by voltage-gated slow calcium channels.

The action potential is prevented from spreading from cell to cell by gap junctions.

What does isovolumetric contraction refer to?

Refers to the short period during ventricular systole when the ventricles are completely closed chambers. (correct)

Occurs immediately after the aortic and pulmonary valves close.

Occurs only in people with heart valve defects.

Occurs while the AV valves are open.

Which of the following is not one of the three main factors influencing blood pressure?

Emotional state Signup and view all the answers

Which of the following chemicals does not work principally on the kidneys?

Nitric acid Signup and view all the answers

Which tunic of an artery contains endothelium?

Tunica intima Signup and view all the answers

Permitting the exchange of nutrients and gases between the blood and tissue cells is the primary function of?

Capillaries Signup and view all the answers

The circulatory route that runs from the digestive tract to the liver is called?

Hepatic portal circulation Signup and view all the answers

The arteries that are also called distributing arteries are the?

Muscular arteries Signup and view all the answers

Aldosterone will?

Promote an increase in blood pressure Signup and view all the answers

The pulse pressure is?

Systolic pressure minus diastolic pressure Signup and view all the answers

Which of the following signs of hypovolemic shock is a relatively late sign?

Rapidly falling blood pressure Signup and view all the answers

Which of the following is likely during vigorous exercise?

Capillaries of the active muscles will be engorged with blood. Signup and view all the answers

Study Notes

Heart Structure and Function

Endocardium: The inner lining of the heart that provides a smooth surface for blood flow.
Myocardium: The thick, muscular layer of the heart responsible for its contraction.
Epicardium: The outer serous layer covering the heart muscle.
Parietal layer: The outermost layer of the serous pericardium.

Electrical Conduction System

SA node: The primary pacemaker of the heart that initiates the heartbeat.
AV bundle: Located in the interventricular septum, it conducts electrical impulses from the atria to the ventricles.
Purkinje fibers: Form a network in the ventricular myocardium to distribute impulses throughout the ventricles.
AV node: Delays the impulse to allow proper ventricular filling before contraction.

Valves of the Heart

Aortic valve: Prevents backflow into the left ventricle.
Tricuspid valve: Prevents backflow into the right atrium and has three flaps.
Mitral valve: Prevents backflow into the left atrium and has two flaps.
Pulmonary valves: Prevents backflow into the right ventricle.

Cardiac Conditions

Ischemia: Condition where heart muscle is deprived of oxygen, possibly leading to pain.
Infarction: Results in death of heart muscle cells.
Fibrillation: Rapid, irregular contraction of heart muscle cells, disrupting normal rhythm.
Ectopic focus: Abnormal pacemaker in the heart outside of the SA node.
Quiescent period: Complete relaxation of the heart muscle.

Blood Flow and Pressure

Brachial artery: Commonly palpated to measure blood pressure.
Femoral artery: Major artery of the thigh.
Capillaries: Site of gas and nutrient exchange; the velocity of blood flow is slowest here.
Large veins: Sites where blood pressure is lowest and where blood volume is greatest.

Heart Function and Regulation

Autonomic regulation: Heart rate is affected by autonomic nervous system activity, primarily via vagal tone.
Coronary arteries: Supply oxygen-rich blood to the heart muscle.
Blood pressure: Greatest in large arteries and lowest in large veins; influenced by vascular resistance.

Physiological Principles

Starling's law: The greater the stretch of myocardial cells (due to increased venous return), the stronger the contraction.
Precapillary sphincters: Regulate blood flow into capillaries.
Vasodilation: Refers to the widening of blood vessels due to smooth muscle relaxation.

Heart Sounds and ECG

Heart sounds: "Lub" denotes closure of AV valves; important for diagnosing valvular function.
P wave in ECG: Represents atrial depolarization.

Pathophysiology and Adaptation

Chronic thyroxine release: Can lead to increased heart rate and reduced heart function.
Atherosclerosis: Causes increased resistance in arteries, requiring higher ventricular pressure to open the aortic valve.

Study Tips

Focus on understanding the relationships between heart structure and function.
Visualize the heart's electrical conduction pathway for better memorization.
Practice drawing diagrams of the heart's anatomy and blood flow pathways.
Familiarize yourself with pathologies to understand their effects on normal heart function.### Cardiology Concepts
The period during ventricular systole when ventricles are closed chambers is crucial for understanding cardiac function.
Blood pressure is influenced by three main factors: cardiac output, peripheral resistance, and blood volume; emotional state is not a primary factor.

Kidney Function and Hormones

Antidiuretic Hormone (ADH), atrial natriuretic peptide, and aldosterone act mainly on the kidneys, whereas nitric acid does not primarily function in this way.

Artery Structure

The tunica media is the layer of an artery that contains endothelium.
Capillaries are vital for nutrient and gas exchange between blood and tissue cells.

Circulatory Routes

Hepatic portal circulation refers to the route from the digestive tract to the liver.
Muscular arteries are also known as distributing arteries, responsible for directing blood flow.

Hormonal Regulation

Aldosterone enhances blood pressure by promoting sodium reabsorption, impacting blood volume.

Blood Pressure Metrics

Pulse pressure is calculated as systolic pressure minus diastolic pressure, providing insight into cardiovascular health.

Shock Symptoms

Rapidly falling blood pressure is a late sign of hypovolemic shock, while cold, clammy skin and rapid, thready pulse occur earlier.

Exercise Physiology

During vigorous exercise, blood flow is prioritized to active muscle capillaries, facilitating enhanced oxygen and nutrient supply, while blood flow to digestive organs is reduced.

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Description

Test your knowledge of the anatomy and physiology of the heart with these flashcards focused on Chapters 18 and 19. Each card presents a term related to heart structure and function, along with its definition. Perfect for students looking to reinforce their understanding of cardiovascular topics.