Study sets, textbooks, questions
Upgrade to remove ads
Biology 2260 Chapter 19 Cardiovascular System
Terms in this set (58)
Describe the general function of the cardiovascular system
The general function of the cardiovascular system is to transport blood throughout the body to allow the exchange of substances (e.g., respiratory gases, nutrients, and waste products) between the blood of capillaries and the body's cells.
The "goal" of the cardiovascular system is to provide adequate perfusion to all body tissues.
Differentiate between the three primary types of blood vessels.
1. Arteries: carry blood away from the heart
2. Veins: carry blood back to the heart
3. Capillaries: exchange sites between either the blood and the air sacs (alveoli) of the lungs or the blood and the body cells.
What are the functions of the 3 different types of blood vessels?
Arteries - the largest blood vessels.they carry Oxygen rich blood AWAY from the heart and out to the body.
capillaries - these are the tiny, thin-walled blood vessels that serve the cells
veins - these carry oxygen depleted blood back to the heart
Describe the structure and function of the heart.
1. Two pumps:
Each pump has a receiving chamber (atrium) and a pumping chamber (ventricle)
.- Right side: pumps deoxygenated blood to the lungs
.- Left side: pumps oxygenated blood to the body.
2. Great vessels:
Arteries (arterial trunks) transport blood away from the heart.
- Pulmonary trunk transports from right side.
- Aorta transports from left side. Veins transport blood toward the heart.
- Vena cavae (SVC and IVC) drain into the right side.
- Pulmonary veins drain into left side.
Heart valves prevent back flow to ensure one-way blood flow.
- Atrioventricular (AV) valves (i.e., right AV valve and left AV valve) are between the atrium and ventricle.
- Semilunar valves (i.e., pulmonary semilunar valve and aortic semilunar valve) are between ventricle and arterial trunk.
Compare and contrast pulmonary circulation and systemic circulation of the cardiovascular system. Trace blood flow through both circuits.
The pulmonary circulation convert deoxygenated blood from the right side of the heart through blood vessels to the lungs for the pickup of oxygen and the release of carbon dioxide, and then back through blood vessels to the left side of the heart.
The systemic circulation moves oxygenated blood from the left side of the heart. The blood vessels to the systemic cells such as those of the liver, skin, muscle, and brain for the exchange of nutrients, respiratory gases, and wastes before returning the blood in vessels that enter the right side of the heart.
Thus, the basic pattern of blood flow is the right side of the heart--->lungs--->the left side of the heart--->systemic tissues of the body --->back to the right side
What different functions are served by the left and right sides of the heart?
right - receives oxygen-poor blood from your veins and pumps it to your lungs, where it picks up oxygen and gets rid of carbon dioxide.
left - receives oxygen-rich blood from your lungs and pumps it through your arteries to the rest of your body.
Describe the location and position of the heart in the thoracic cavity.
The heart is located posterior to the sternum left of the body midline between the lungs in the mediastinum. The posterosuperior surface of the heart is called the base. The inferior, conical end of the heart is called the apex.
*Think of the heart's position like an "upside down" pyramid with the apex below the base.
List the structural components of the pericardium.
The pericardium that encloses the heart includes the pericardial sac, which has an outer fibrous pericardium and an inner parietal layer of serious pericardium, and a visceral layer of serous pericardium (epicardium) that forms the outer layer of the heart wall.
Describe the function of the pericardium and the purpose of the serous fluid within the pericardial cavity.
The pericardial cavity is a potential space between the layers of the serous pericardium that contain serous fluid, which is produced by the serous membranes and lubricates the surfaces to reduce friction.
What is the mediastinum?
structure separating the right and left thoracic cavities
Where around the heart is serous fluid located?
Compare the superficial features of the anterior and posterior aspects of the heart.
The right side of the heart is more visible from the anterior view, and the left side of the heart is more visible from the posterior view.
Name the three layers of the heart wall and the tissue components of each
1. Epicardium: outermost layer that is also called the visceral layer of serous pericardium.
2. Myocardium: the middle and thickest layer. Contraction of the cardiac muscle in the myocardium generates the force necessary to pump blood.
3. Endocardium: covers the internal surface of the heart and the external surfaces of the heart valves. It is continuous with the inner lining of blood vessels.
Characterize the four chambers of the heart and their functions
The right atrium receives oxygen-poor blood from the body and pumps it to the right ventricle. The right ventricle pumps the oxygen-poor blood to the lungs. The left atrium receives oxygen-rich blood from the lungs and pumps it to the left ventricle. The left ventricle pumps the oxygen-rich blood to the body.
Compare and contrast the structure and function of the two types of heart valves.
Each valve consists of endothelium-lined fibrous connective tissue flaps called cusps, or leaflets.1. Atrioventricular valves- the right AV valve covers the right atrioventricular opening, and it has three cusps; the left AV valve covers the left atrioventricular opening, but it only has two cusps. - When open, the cusps of the valve extend into the ventricles, allowing blood to move from an atrium into the opening of a ventricle. This causes the AV valves to close. - The papillary muscles secure the thin chordae tendineae that attach to the lower surface of each AV valve cusp, preventing blood flow back into the atrium.2. Semilunar valves - the pulmonary semilunar valve is located between the right ventricle and the pulmonary trunk, and the aortic semilunar valve is located between the left ventricle and the aorta.- each valve is composed of three cusps- neither papillary muscles nor chord tendineae are associated with these valves. - The semilunar valves open when the ventricles contract and the force of the blood pushes the AV valves open and blood enters the arterial trunks.- The valves close when the ventricles relax and the pressure in the ventricle becomes less than the pressure in a great arterial trunk. - Blood in the arteries begins to fall backward toward the ventricle and is caught in the cusps of the semilunar valves, and they close, preventing the back flow of blood into the ventricle.
Describe the general structure of cardiac muscle.
Cardiac muscle cells are small, have one or two centrally located nuclei, and are branched.
Explain the intercellular structures of the cardiac muscle.
Intercalated discs tightly link the cardiac muscle cells together and permit the passage of action potentials.
- Desmosomes act as mechanical junctions to prevent cardiac muscle cells from pulling apart.
- Gap junctions provide a low-resistance pathway for the flow of ions between cardiac cells. They allow an action potential to move continuously along the sarcolemma of cardiac muscle cells, resulting in synchronous contraction of that chamber.
Describe the location and function of the fibrous skeleton.
The fibrous skeleton provides an attachment site for heart valves and cardiac muscle, and prevents action potentials from spreading between the atria and ventricles except through the AV node.
What is the inner layer of the heart wall and describe its function
endocardium - This is the smooth innermost layer that keeps blood from sticking to the inside of the heart.
What type of heart valve is associated with tendinous cords?
What 2 functions do intercalated discs serve?
The intercalated discs are junctions that permit ions to pass between the cell, which transmits the electrical impulse rapidly. They also have desmosomes which propel the force from each contraction to the next cell. The intercalated discs appear as thin vertical strips along the band of the cell
Identify the coronary arteries, and describe the specific areas of the heart supplied by their major branches.
Coronary arteries supply oxygenated blood to the heart wall and include the left and right coronary arteries that branch off the aorta.
- three major coronary arteries off the right side of the heart (RMP): the right coronary artery splits into the right marginal artery and posterior inter ventricular artery
- three major coronary arteries off the left side of the heart (LAC): the left coronary artery, the anterior inter ventricular artery, and circumflex artery.
Explain the significance of coronary arteries as functional end arteries.
Some arteries may share connections, called arterial anastomoses. Other arteries terminate in capillary beds only, and are called end arteries. The left and right coronary arteries are considered functional end arteries because, although there coronary arteries have anastomoses, if one of the arteries becomes blocked these anastomoses are too tiny to shunt sufficient blood from one artery to the other. As a result, the part of the heart wall that was supplied by one coronary artery branch will die due to lack of blood flow to the tissue.
Describe blood flow through the coronary arteries.
Blood flow to the heart wall is not a steady stream; it is impeded and then flows, as the heart rhythmically contracts and relaxes.
Identify the coronary veins and describe the specific areas of the heart drained by their major branches.
Venous return is through the cardiac veins (great, middle, and small) into the coronary sinus, which collects venous blood and drains deoxygenated blood from the heart wall directly into the right atrium of the heart.
Which coronary artery gives rise to the circumflex artery?
left marginal artery
Identify and locate the components of the heart's conduction system.
Stimulation of the heart involves the initiation of an action potential at the SA node and its transmission through the conduction system.
The conducting system includes sinoatrial (SA) node, atrioventricular (AV) node, AV bundle, and Purkinje fibers, which are composed of specialized cardiac cells that initiate and conduct action potentials resulting in a heartbeat.
Compare and contrast parasympathetic and sympathetic innervation to the heart.
Parasympathetic innervation comes from the cardioinhibitory center to decrease the heart rate..
Sympathetic innervation comes from the cardioacceleratory center to increase the heart rate and increase force of contraction.
Which of the two autonomic nervous system divisions has an effect on the force of heart contraction?
What is the cardioinhibitory center and where is it located?
a vasomotor center in the medulla oblongata that exerts an inhibitory influence on the heart.
SA nodal cells are unique in that they exhibit autorhythmicity, meaning that they are capable of depolarizing and firing an action potential spontaneously without external influence.
Describe the steps for SA nodal cells to spontaneously depolarize and serve as the pacemaker cells.
1. Reaching threshold as Na+ enters the nodal cells through open voltage-gated Na+ channels
2. depolarization as Ca2+ enters the nodal cells through open voltage-gated Ca2+ channels3. Repolarization as K+ exits the nodal cells through voltage-gated K+ channels
At rest, the parasympathetic nervous system decreases the inherent rhythm of nodal cells from a firing rate of 100 per minute to 75 per minute.
Describe the spread of the action potential through the heart's conduction system.
The action potential travels through the conduction system as follows:
1. SA node
2. AV node
3. AV bundle
4. bundle branches
5. Purkinje fibers
Following stimulation by the conduction system, there is a propagation of the action potential at the sarcolemma and contraction of sarcomeres within the cardiac muscle cells.
List the electrical events of an action potential that occur at the sarcolemma.
The electrical events of cardiac muscle include depolarization, plateau, and depolarization at the sarcolemma.
Briefly summarize the mechanical events of muscle contraction.
The mechanical events are similar to those of skeletal muscle fibers and involve cross bridge cycling and the shortening of sarcomeres within cardiac muscle cells.
Define the refractory period.
Cardiac muscle exhibits a longer refractory period than skeletal muscle fibers to allow time for contraction and relaxation of the muscle cells before they are stimulated again- a necessary requirement for the "pumping action" of the heart.
Identify the components of an ECG recording.
An electrocardiogram (ECG) is a graphic recording of the electrical changes in the heart and is used in the diagnosis and treatment of abnormal heart function.
Identify the two processes within the heart that occur due to pressure changes associated with the cardiac cycle.
A cardiac cycle is the inclusive period of time from initiation of one heartbeat to the start of the next.
1. Systole: contraction of a chamber
2. Diastole: relaxation of a chamber
What is happening in the heart during the Q-T interval?
The ventricles are contracting (systole).
List the five events of the cardiac cycle.
1. Atrial systole
2. Early ventricular systole
3. Late ventricular systole
4. Early ventricular diastole
5. Late ventricular diastole
List and describe what occurs during the five events of the cardiac cycle.
1. Atrial systole is the contraction of atria to finish filling the ventricles, which are in diastole.
2. Early ventricular systole is a time of isovolumetric contraction: Ventricles begin to contract, AV valves are pushed closed, and no blood leaves the ventricles yet.
3. Late ventricular systole is the time of ventricular ejection: Semilunar valves are pushed open, and blood is forced through the semilunar valves into the arterial trunk.
4. Early ventricular diastole is the beginning of ventricular relaxation: AV valves remain closed, and semilunar valves close.
5. Late ventricular diastole is a time to begin ventricular filling as AV valves open and passive filling of the ventricle begins.
Explain the significance of ventricular balance.
This is the equal amount of blood being pumped by the left and right sides of the heart; if not met, edema can occur
Which heart valves open during ventricular ejection?
aortic and pulmonic
If cardiac muscle were weakened, would ESV increase or decrease?
Define cardiac output
Cardiac output is a measure of how effective the cardiovascular system is in transporting substances through the body.
It is defined as the amount of blood pumped by a single ventricle in 1 minute.
Cardiac output is the heart rate multiplied by the stroke volume.
Explain what is meant by cardiac reserve.
Cardiac reserve is a measure of the ability of the heart to increase pumping capacity beyond the normal resting cardiac output (CO).
Define chronotropic agents, and describe how they affect heart rate.
Heart rate is altered through chronotropic agents, which change SA node and AV node activity.
Positive chronotropic agents increase the heart rate and the negative chronotropic agents decrease the heart rate.
List the three variable that may influence stroke volume.
Stroke volume is influenced by venous return, inotropic agents, and afterload.
Define each of the three variables, and describe the factors that influence each one and how it affects stroke volume.
Venous return is directly correlated with store volume.
Positive inotropic agents increase stroke volume, negative inotropic agents decrease stroke volume.
Afterload is inversely related to stroke volume.
Summarize the variables that influence cardiac output.
Heart rate is altered by stimulating the conducting system, and stroke volume is usually altered by changes in the myocardium.
Both heart rate and stroke volume are directly related to cardiac output.
How do positive inotropic agents affect cardiac output?
help the heart pump more blood with fewer heartbeats. This means that although the heart beats less, it also beats with more force to meet the oxygen demands of your body.
What is an example of a negative inotropic agent?
beta blockers, calcium Channel blockers
How does the heart respond to increased venous return?
increased cardiac output
Explain the Bainbridge reflex
The Bainbridge reflex (aka, atrial reflex) occurs when the heart rate increases in response to a rise in atrial pressure.
What does the Frank-Starling law tell us?
the stroke volume of the left ventricle will increase as the left ventricular volume increases due to the myocyte stretch causing a more forceful systolic contraction.
What is after load?
the active stress that the ventricular muscle needs to generate to eject blood from the ventricle.
Describe septal defects that may occur during development
a ventricular septal defect occurs when the muscular wall separating the heart into left and right sides (septum) fails to form fully between the lower chambers of the heart (ventricles)
What occurs if the foramen oval of the heart does not close at birth?
patent foramen ovale
Other sets by this creator
Biology 2260 Cardiovascular System
Biology 2260 Chapter 17
Biology Lab: Senses
Biology Lab: Spinal Cord and Spinal Nerv…