Videos

3_The Heart and Circulatory System - How They Work, 4_High Blood Pressure Basics, 5_The Heart, Part 1 - Under Pressure: Crash Course A&P #25, 6_The Heart, Part 2 - Heart Throbs: Crash Course A&P #26, 7_The Respiratory System, 8_Respiratory System, Part 1: Crash Course A&P #31

What is the primary function of the heart?

To pump blood throughout the body.

Where is the heart located in the body?

Slightly left of center in the chest.

What are the two main sides of the heart?

The right side and the left side.

What does the division of the heart prevent?

Mixing of oxygen-rich blood with oxygen-poor blood.

How much blood does the heart pump every minute?

About five quarts.

How many times does the heart beat in one day?

About 100,000 times.

What are the four chambers of the heart?

Right atrium, right ventricle, left atrium, left ventricle.

What is the role of the right side of the heart?

To collect oxygen-poor blood and pump it to the lungs.

What happens to blood in the lungs?

It gets refreshed with oxygen and turns red.

What is the function of the left side of the heart?

To pump oxygen-rich blood to the body.

What are the names of the four heart valves?

Tricuspid, mitral, pulmonary, and aortic valves.

What is the contraction phase of the heart called?

Systole.

What is the relaxation phase of the heart called?

Diastole.

What do coronary arteries do?

They supply blood to the heart muscle itself.

What is the conduction system of the heart responsible for?

Keeping the heart beating in a coordinated rhythm.

What is blood pressure a measure of?

The strain on arteries as the heart pumps blood.

What can high blood pressure lead to?

Kidney disease, heart disease, stroke, and heart attack.

What is the average size of an adult human heart?

About the size of two fists clasped together.

What is the pericardium?

A double-walled sac that surrounds and protects the heart.

What are the three layers of the heart wall?

Epicardium, myocardium, and endocardium.

What is the septum in the heart?

A thin inner partition that divides the heart into two sides.

What do the atria of the heart do?

They are low-pressure areas that receive blood.

What do the ventricles of the heart do?

They produce high pressures to pump blood out of the heart.

How does blood flow through the heart?

It flows in one direction through the chambers and valves.

What happens when a heart valve closes?

No blood can flow back into the chamber it just left.

What sound do you hear when listening to a person's heart?

The 'lub-DUB' sound, which is caused by the heart valves opening and closing.

What are the two main types of chambers in the heart?

Atria and ventricles.

What is the function of the atria in the heart?

They are the receiving chambers for blood returning to the heart.

What is the role of the ventricles in the heart?

They are the discharging chambers that pump blood out of the heart.

Why are atria walls thinner than ventricles?

Atria receive blood under low pressure, requiring less muscular effort.

What is the primary function of arteries?

To carry blood away from the heart.

What is the primary function of veins?

To carry blood back toward the heart.

What is unique about the pulmonary arteries?

They carry deoxygenated blood from the heart to the lungs.

What happens in the lungs during pulmonary circulation?

Blood picks up oxygen and releases carbon dioxide.

What is the pulmonary circulation loop?

The path blood takes from the right ventricle to the lungs and back to the left atrium.

What initiates the systemic loop in the circulatory system?

The left ventricle contracting to pump oxygenated blood into the aorta.

What happens to oxygen-poor blood after it circulates through the body?

It returns to the heart via the superior and inferior vena cava into the right atrium.

What are the two phases of the heart cycle related to blood pressure?

Systole (ventricles contract) and diastole (ventricles relax).

What does systolic blood pressure measure?

The peak pressure in the arteries during ventricular contraction.

What does diastolic blood pressure measure?

The pressure in the arteries when the ventricles are relaxed.

What can low systolic blood pressure indicate?

It may suggest low blood volume due to blood loss or dehydration.

What can high diastolic blood pressure indicate?

It may suggest high blood pressure even when the heart is at rest.

What is the significance of maintaining blood pressure homeostasis?

It is crucial for preventing damage to arterial walls and ensuring proper circulation.

What are the consequences of prolonged high blood pressure?

It can damage arterial walls and endanger vital organs like the heart, lungs, and kidneys.

What is the function of heart valves?

To regulate blood flow and maintain pressure within the heart chambers.

What causes the 'lub' sound in the heart?

The closing of the mitral and tricuspid valves during ventricular contraction.

What causes the 'DUB' sound in the heart?

The closing of the aortic and pulmonary semilunar valves at the start of diastole.

What is the overall path of blood circulation in the body?

Heart to lungs to heart to body and back to the heart.

What is the role of capillaries in the circulatory system?

They allow for the exchange of oxygen and carbon dioxide between blood and tissues.

What is the primary function of CPR during cardiac arrest?

To help prolong heart function until a defibrillator can be used.

What is the common misconception about defibrillators in popular culture?

That they restart the heart; in reality, they stop the heart to reset its rhythm.

What distinguishes cardiac muscle cells from skeletal muscle cells?

Cardiac cells are branched, interconnected, and have one or two central nuclei, while skeletal cells are long and multinucleate.

What is the role of mitochondria in cardiac muscle cells?

They provide energy, making up 25 to 35 percent of each cardiac cell, which helps resist fatigue.

How are cardiac muscle cells connected compared to skeletal muscle cells?

Cardiac cells are both physically and electrically connected, allowing for coordinated contractions.

What are pacemaker cells?

Special heart cells that generate their own electrical impulses to maintain the heart's rhythm.

Where are the fastest pacemaker cells located in the heart?

In the sinoatrial node (SA node) in the right atrium.

What is the intrinsic cardiac conduction system?

The pathway that transmits electrical impulses through the heart, coordinating contractions.

What happens at the atrioventricular node (AV node)?

The electrical signal is delayed to allow the atria to contract before the ventricles.

What is the function of the bundle of His?

To distribute the electrical signal to the left and right ventricles.

How do Purkinje fibers contribute to heart function?

They trigger depolarization in surrounding cells, causing coordinated ventricular contractions.

How long does the entire cardiac cycle take from SA node firing to ventricular contraction?

About 220 milliseconds.

What analogy is used to describe the function of heart cells during a malfunction?

They are compared to musicians in an orchestra without a conductor, leading to uncoordinated rhythms.

What is the purpose of the endomysium in cardiac muscle tissue?

To provide a loose matrix of connective tissue filled with capillaries for oxygen supply.

What is the significance of the leaky sodium and potassium channels in pacemaker cells?

They allow a steady influx of sodium ions, causing the membrane potential to drift toward threshold and trigger action potentials.

What is the consequence of the atria contracting before the ventricles?

It ensures that blood flows efficiently from the atria to the ventricles before the ventricles contract.

What is the role of the cardiac conduction system in heartbeats?

To ensure that electrical impulses are transmitted in a coordinated manner for effective heart contractions.

Why is it important for the ventricles to contract from the bottom up?

To accelerate blood flow through the large arteries at the top of the heart.

What happens to heart cells during cardiac arrest?

They may become uncoordinated, leading to ineffective pumping of blood.

What is the relationship between cardiac muscle tissue structure and its function?

The interconnected structure allows for synchronized contractions necessary for effective blood pumping.

How does the heart maintain a consistent rhythm without external stimuli?

Through pacemaker cells that autonomously generate action potentials.

What is the impact of the AV node's delay on heart function?

It prevents simultaneous contraction of all heart chambers, allowing for effective blood flow.

What is the primary energy source for cardiac muscle cells?

Mitochondria, which generate ATP to support continuous heart activity.

How does the structure of cardiac muscle cells contribute to their endurance?

Their high mitochondrial content allows them to resist fatigue and sustain long periods of activity.

What is fibrillation in the heart?

Fibrillation is an out-of-sync behavior caused by problems affecting the pacemaker cells in the SA node, leading to uncoordinated contractions.

What role does a defibrillator play in heart function?

A defibrillator acts like a conductor, stopping chaotic heart activity and resetting the rhythm by sending electrical impulses to the heart.

How does a defibrillator reset the heart's rhythm?

It sends a large electrical shock that triggers action potentials in heart cells simultaneously, allowing the pacemaker cells to regain control.

What is the function of pacemaker cells in the heart?

Pacemaker cells generate action potentials that regulate the heart's rhythm and ensure coordinated contractions.

What is cardiopulmonary resuscitation (CPR) unable to do?

CPR cannot correct fibrillation; it only helps circulate oxygenated blood until further medical help arrives.

What is the primary function of the respiratory system?

The respiratory system facilitates the exchange of oxygen and carbon dioxide through breathing.

What structures are included in the respiratory system?

The respiratory system includes the nose, throat, voice box (larynx), windpipe (trachea), and lungs.

What is the role of cilia in the respiratory system?

Cilia are tiny hairs that filter out dust and particles from the air entering the nasal passageways and respiratory tract.

What is the function of the epiglottis?

The epiglottis is a flap of tissue that covers the airway during swallowing to prevent food and liquid from entering the lungs.

How does the trachea maintain its structure?

The walls of the trachea are supported by stiff rings of cartilage that keep it open.

What are bronchioles and where do they lead?

Bronchioles are smaller branches of the bronchi that lead to tiny air sacs called alveoli in the lungs.

What are alveoli and what is their function?

Alveoli are tiny air sacs in the lungs where the exchange of oxygen and carbon dioxide occurs with surrounding capillaries.

How does exercise affect the respiratory system?

Exercise increases the demand for oxygen, causing the respiratory system to work harder and adapt by increasing lung capacity and efficiency.

What evolutionary milestone did early vertebrates achieve?

Early vertebrates developed lungs to breathe air, allowing them to adapt to changing environmental conditions.

What is diffusion in the context of respiration?

Diffusion is the process by which oxygen moves from areas of high concentration to low concentration, allowing organisms to extract oxygen from water.

Why did early life forms need a circulatory and respiratory system?

As life forms grew larger, they required more efficient systems to transport oxygen and facilitate gas exchange.

What adaptations did lobe-finned fish develop for breathing air?

Lobe-finned fish evolved lungs that allowed them to breathe air, which was crucial as water conditions changed.

What happens to carbon dioxide during respiration?

Carbon dioxide is transferred from the bloodstream into the alveoli, where it is expelled from the body during exhalation.

What is the significance of the SA node in the heart?

The SA node is the heart's natural pacemaker, initiating electrical impulses that regulate heartbeats.

What is the relationship between the respiratory system and physical activity?

Regular physical activity enhances the efficiency of the respiratory system, improving oxygen uptake and carbon dioxide removal.

How does the body respond to increased oxygen demand during exercise?

The body increases the rate and depth of breathing to supply more oxygen and remove carbon dioxide efficiently.

What common ancestor do all lung-having vertebrates share?

An ancient fish that led to significant anatomical developments.

What components make up the respiratory system in mammals?

Lungs, protective ribs, a stiff trachea, and a strong diaphragm.

How do the respiratory and circulatory systems work together?

They collaborate using bulk flow and simple diffusion to facilitate cellular respiration.

What is the role of simple diffusion in respiration?

It allows oxygen to move from the air into the blood, but is inefficient over long distances.

What is bulk flow in the context of respiration?

It refers to the rapid movement of large numbers of molecules, such as oxygen, into the lungs.

How do lungs function in the respiratory system?

They act like a pump or bellows, requiring external help to expand and contract.