Circulatory System
Arteries typically have high pressure, while veins have low pressure. Pressure decreases as blood flows throughout systemic circulation.
Detail blood pressure throughout systemic circulation.
ΔP = Q * R ΔP = Difference in pressure at two points in the circulatory system Q = Cardiac output in volume/min R = resistance of vessel
How is blood pressure throughout the circulatory system calculated?
Outer layer: Parietal pericardium Inner layer: Visceral pericardium (epicardium)
What are the two layers of that make up the pericardium?
Detect and regulate blood pressure
What do baroreceptors do in a blood vessel?
sphygomomanometer (stethoscope)
What instrument is used to measure blood pressure?
VSD stands for Ventricular Septimal Defect, and it is a common birth defect found in newborns, where the membraneous interventricular septum has holes in it, causing blood to flow between the right and left ventricle.
What is VSD and describe it.
Arteries carries blood away from the heart Veins carries blood towards the heart
What is the defining difference between arteries and veins?
Separate the right and left ventricles
What is the purpose of the interventricular septum?
-Endothelial cells -Proteinous basement membrane
What makes up the tunica intima of a blood vessel?
Pulmonary = Right Systemic = Left
Which side of the heart supports pulmonary circulation? What about systemic circulation?
Hypertension
_______________________ is a pathological state of high blood pressure that may result in damage to the blood vessels and organs.
-Endocardium -Myocardium -Pericardium
Name the three layers of the heart from innermost to outermost layer.
Sinoatrial (SA) node -> Atrioventricular (AV) node -> bundle of His -> Purkinje fibers
Starting with the site of impulse initiation, what are the structures in the conduction system of the heart?
Thorax
The _______________________ is the area that the heart and lungs are located in, which is above the diaphragm muscle and surrounded by the rib cage.
Collagen
The basement membrane of the tunica intima is mostly made up of __________________.
R = 1/r^4 R = resistance r = radius of tube
How is resistance calculated in a blood vessel?
Increases Decreases
Activation of the sympathetic nervous system (increases/decreases) cardiac output, while activation of the parasympathetic nervous system (increases/decreases) cardiac output.
Decrease Increase
All systemic capillary beds are in parallel with each other (except for the three portal systems); therefore, opening capillary beds will (increase/decrease) vascular resistance and (increase/decrease) cardiac output.
Thermoregulation is controlled by the circulatory system through the vasodilation and vasoconstriction of capillaries under the skin. Skin typically acts as insulation of heat inside the body, but capillaries near the surface of the skin bypasses this insulation, and allowing heat to escape the body. If the body feels cold, the capillaries will shrink (vasoconstriction), causing less blood to flow through, and less heat escapes the body. If the body feels hot, the capillaries will expand (vasodilation), causing more blood to flow through, and more heat escapes the body.
Describe how the circulatory system plays a role in thermoregulation in the body.
Autonomic nervous system
Which part of the nervous system regulates the circulatory system?
Systole Diastole
Contraction of ventricles during _____________ generates higher pressure in the ventricles, while relaxation of ventricles during _______________ lowers pressure in ventricles.
1. Oxygenated blood flows from the left ventricle of the heart through the aortic valve, and enters the aorta. 2. Oxygenated blood flows from the aorta into branching arteries, which then flows into branching arterioles. 3. Oxygenated blood then flows from the arterioles into capillaries, which is where tissue exchanges CO2 in them for O2 in the blood, which makes the blood deoxygenated. 4. Deoxygenated blood flows from the capillaries and into venules, which then flows into conjoining veins. 5. Deoxygenated blood flows from the veins into the conjoining vena vava (superior or inferior), which dumps the blood into the right atrium.
Detail the flow of blood in the systemic circulatory system.
-Some major veins have valves that allows them to push blood up through themselves, while preventing backflow of blood. -Most veins are surrounded by skeletal muscles, which squeezes the veins as muscles contract, forcing blood up against gravity.
Since veins have to pump blood back to the heart, it must fight the force of gravity in order to pump blood through the veins. How are the veins able to do this?
Systemic circulation Pulmonary circulation
The flow of blood between the heart and the rest of the body is referred to as ___________________________, while the flow of blood between the heart and the lungs is referred to as _______________________.
1. Hepatic portal system - passes capillary bed in the gut and the liver before returning to the heart 2. Hypophyseal portal system - passes capillary bed in the hypothalamus and the anterior pituitary before returning to the heart. 3. Renal portal system - passes capillary bed in the glomerous and the vasa recta
Usually blood only passes through one capillary bed before returning to the heart. What are the 3 exceptions to this rule?
Length: the longer the blood vessel, the more resistance it offers, the shorter the blood vessel, the less resistance it offers. Radius: A larger radius of the vessel leads to less resistance, while a smaller radius leads to more resistance.
What are some factors that affect resistance in the blood?
Systole The atrioventricular valves snap shut while the semilunar valves open. Both ventricles contract, pushing blood from the right and left ventricles into the pulmonary artery and the aorta, respectively.
What is the period between the S1 sound and the S2 sound in the heart? Detail what happens during that period.
Diastole The semilunar valves snap shut while the atrioventricular valves open. Both ventricles relax, while the opening of the atrioventricular valves causes blood to flow from the atria to the ventricles.
What is the period between the S2 sound and the second S1 sound in the heart? Detail what happens during that period.
Allows these arteries and arterioles to increase or decrease resistance in order to change blood pressure.
What is the purpose for small arteries & arterioles to contain more concentrations of smooth muscles than other vessels?
-Consists of a proteinous coating -Nerve endings -Large blood vessels will have smaller blood vessels on the tunica externa/adventitia, known as vasa vasorum
What makes up the tunica externa/adventitia in a blood vessel?
Arteries: Aorta Veins: Right atrium
Where do coronary arteries originate from? What about coronary veins?
Myocardium
Which layer of the heart is responsible for expending energy to keep the heart beating?
The left side of the heart is more muscular because that side requires to be more muscular in order to pump blood long distances throughout the body.
Which side of the heart is more muscular and why?
1. Deoxygenated blood flows into the right atrium through the superior or inferior vena cava. 2. Deoxygenated blood flows from the right atrium to the right ventricle. 3. Deoxygenated blood flows from the right ventricle and into the pulmonary artery, where it gets taken to the lungs. 4. Oxygenated blood flows from the pulmonary veins and into the left atrium. 5. Oxygenated blood flows from the left atrium to the left ventricle. 6. Oxygenated blood flows from the left ventricle and into the aorta, where it flows to different parts of the body.
Detail the flow of blood through the heart.
Pumps deoxygenated blood from the parts of the body above the thorax Pumps deoxygenated blood from the parts of the body below the thorax
What type of blood does the superior vena cava pump into the heart? What type of blood does the inferior vena cava pump into the heart.
increases decreases vasoconstriction
When arteries contracts, the resistance in the arteries _____________________, which means blood flow ______________________. This is referred to as _________________.
Answer: C. Q = H * S Q = Cardiac output H = Heart rate S = Stroke volume Q = 7500 mL/min S = 50 mL/beat 7500 mL/min = H * 50 mL/beat H = 7500 mL/min 50 mL/beat H = 150 beats/min
A patient's chart reveals that he has a cardiac output of 7500 mL per minute and a stroke volume of 50 mL. What is his pulse, in beats per minute? A. 50 B. 100 C. 150 D. 400
-Do not have three layers like arteries and veins -Structure consists of only one cell wrapped around the lumen
Detail the structure of capillaries.
Veins Veins contains 65% of total blood volume in the body, while arteries contains 15% of total blood volume in the body.
Are arteries or veins greater in blood volume in the circulatory system?
A. Superior vena cava B. Pulmonary veins C. Inferior vena cava D. Arteries E. Aorta F. Pulmonary arteries G. Coronary artery H. Coronary vein I. Right atrium J. Tricuspid valve K. Right ventricle L. Pulmonary valve M. Aortic valve N. Left atrium O. Mitral/Bicuspid valve P. Left ventricle
Identify the different structures of the heart.
A. Papillary muscles B. Chordae tendineae C. Membraneous interventricular septum D. Muscular interventricular septum
Identify the labeled structures of the heart.
It decreases the most when blood passes through the arteriole on its way to the capillaries.
At what point in the circulatory system does the pressure decrease dramatically?
Q = H * S H = 70 bpm (beats/minute) S = 70 ml/beat Q = 70 beats/min * 70 ml/beat Q = 4900 ml/min or 4.9 L/min
If a man who weighs 70 kg has a stroke volume of 70 ml per beat and has a heart rate of 70 bpm, what would be the cardiac output from the left ventricle?
ΔP = Q * R ΔP = 95 mmHg - 5 mmHg ΔP = 90 mmHg Q = 5 L/min 90 mmHg = 5 L/min * R 90 mmHg/5 L/min = R R = 18 mmHg * min L
If the blood pressure in the aorta is measured to be 95 mmHg and blood pressure of the vena cava is measured to be 5 mmHg. What would be the body's total resistance to blood flow if 5 L of blood is flowing through the circulatory system every minute?
Answer: A. The relative lack of smooth muscle in venous walls allows stretching to store most of the blood in the body. Valves in the veins allow for one-way flow of blood towards the heart, not stretching. Both arteries and veins are close to lymphatic vessels, which has no bearings on their relative difference in volume. Both arteries and veins have a single-cell endothelial lining.
At any given time, there is more blood in the venous system than the arterial system. Which of the following features of the veins allow for this? A. Relative lack of smooth muscle in the wall B. Presence of valves C. Proximity of veins to lymphatic vessels D. This endothelial lining
1. A: Away from the heart C: From arterioles to venules V. Towards the heart 2. A: Thick C: Very thin V: Thin 3. A: A lot C: None V: A little 4. A: No C: No V: Yes
Compare and contrast arteries, capillaries, and veins for the following categories: 1. Which direction they carry blood? 2. Relative thickness of wall 3. Are smooth muscles present? 4. Do they contain valves?
-The middle layer of the heart -The thickest layer of the heart, and contains a lot of contractile muscles.
Describe the myocardium.
intercalated discs
Muscle cells in the heart are connected by ________________________, which contains specialized connections between myocardial cells containing gap junctions and desmosomes, which allows for coordinated ventricular contractions.
1. Impulse is initially formed at the SA node 2. A wave of depolarization spreads from the SA node causing the two atria to contract simultaneously, which results in a little bit more blood to be forced into the ventricles. Known as the atrial kick. 3. The wave of depolarization from the SA node reaches the AV node at the atrioventricular valves. 4. The signal is delayed at the AV node in order for the ventricles to fill up before contraction. 5. Once ventricles are filled, signal travels down the bundle of His and its branches to reach the Purkinje fibers. 6. The signal acting of the bundle branches and the Purkinje fibers causes them to distribute electrical signals throughout the ventricular muscles, causing them to contract and pump blood into the pulmonary artery (right ventricle) and the aorta (left ventricle).
Describe the pathway of electrical impulses generated in the heart.
1. Deoxygenated blood leaves the right ventricle through the pulmonary valve, and enters the pulmonary trunk 2. Deoxygenated blood flows through pulmonary trunk, which then splits into two branching paths, known as pulmonary arteries, each flowing blood to the right or left lung. (Right pulmonary artery goes to right lung, Left pulmonary artery goes to left lung). 3. Deoxygenated blood enters the lungs, and flows into the capillaries on the aveoli, which exchanges the CO2 in the blood for O2, which makes the blood oxygenated. 4. Oxygenated blood exits the lungs, and flows through the pulmonary veins, which enters the left atrium of the heart.
Detail the flow of blood in the pulmonary circulatory system.
-Tunica intima contains endothelial cells and a collagenous basement membrane -Tunica media is thicker than veins, consists of smooth muscles and elastin proteins. -Tunica externa/adventitia consists of proteinous membrane and sometimes blood vessels and nerve endings
Detail the structure of large & medium arteries. (Be sure to include the three tunica layers)
-Tunica intima contains endothelial cells and a collagenous basement membrane -Tunica media is thicker than veins, concentrated with a lot of smooth muscles. -Tunica externa/adventitia consists of proteinous membrane.
Detail the structure of small arteries & arterioles. (Be sure to include the three tunica layers)
Veins lack the amount of smooth muscles that arteries have, which allows for veins to stretch in order to accommodate for larger quantities of blood.
How are veins able to contain more blood than arteries.
They don't Red blood cells do not have mitochondria, meaning that they do not need to use oxygen inside the cell at all. It just carries around oxygen in the blood using hemoglobin proteins.
How do red blood cells receive oxygen?
The heart has blood vessels on it that transports oxygenated blood to the cells, and transports deoxygenated blood back to the right atrium. These vessels are known as coronary arteries and coronary veins respectively.
How does the heart receive oxygen?
1. Aortic valve opens 2. Aortic valve closes 3. Mitral valve closes 4. Mitral valve opens A. Aortic pressure B. Left atrial pressure C. Ventricular volume D. Left ventricular pressure
Identify the labeled areas of the cardiac cycle chart. Numbers indicates events in the cycle. Letters indicates what each line represents.
A. Sinoatrial node (SA node) B. Atrioventricular node (AV node) C. The bundle of His D. Left bundle branch (LBB) E. Right bundle branch (RBB) F. The Purkinje fibers
Identify the labeled structures of the heart.
The heart will still be beating at an intrinsic rate of the SA node, but the individual will be unable to change his or her heart rate via the sympathetic or parasympathetic nervous system.
If all autonomic input to the heart were cut, what would happen?
Dehydration
If blood osmolarity is too high, what would that indicate?
Right atrium -> tricuspid valve -> right ventricle -> pulmonary valve -> pulmonary arteries -> pulmonary capillaries -> pulmonary veins -> left atrium -> bicuspid/mitral valve -> left ventricle -> aortic valve -> aorta -> arteries -> arterioles -> capillaries -> venules -> veins -> vena cava -> right atrium
Starting with the right atrium, describe the flow of blood throughout the circulatory system.
60 - 100 signals per minute 60 - 100 beats per minute
The SA node is able to generate _____________________ signals per minute without neurological input, meaning that the normal heart rate of a human is _______________________ bpm.
1. Keep blood flowing in the body flowing. (Systemic circulation) 2. Keep blood flowing to and from the lungs (Pulmonary circulation)
What are the functions of the heart?
Tunica intima Tunica media Tunica externa/adventitia
What are the three layers that makes up a blood vessel in the order of innermost layer to outermost layer?
They are the location of gas and nutrient exchange in the circulatory system. Capillaries in the lungs exchanges O2 in the lungs with CO2 in the blood. Capillaries in the systemic circulatory system exchanges CO2 from tissues with O2 in the blood
What is the purpose of capillaries in the circulatory system?
Coronary arteries delivers oxygenated blood from the aorta to the cells of the heart. Coronary veins delivers deoxygenated blood from the cells of the heart direct to the right atrium.
What is the purpose of coronary arteries and coronary veins?
decreases increases vasodilation
When arteries relax, the resistance in the arteries _______________________, which means blood flow _____________________. This is referred to as _____________________.
Answer: A. Blood drains from the superior and inferior venae cavae into the right atrium. It passes through the tricuspid valve and into the right ventricle, and then through the pulmonary valve into the pulmonary artery, which leads to the lungs. Oxygenated blood returns to the left atrium via the pulmonary veins. It flows through the mitral valve into the left ventricle. From the left ventricle, it is pumped through the aortic valve into the aorta for distribution throughout the body.
Which of the following correctly traces the circulatory pathway? A. Superior vena cava -> right atrium -> right ventricle -> pulmonary artery -> lungs -> pulmonary veins -> left atrium -> left ventricle -> aorta B. Superior vena cava -> left atrium -> left ventricle -> pulmonary artery -> lungs -> pulmonary veins -> right atrium -> right ventricle -> aorta C. Aorta -> right atrium -> right ventricle -> pulmonary artery -> lungs -> pulmonary veins -> left atrium -> left ventricle -> superior vena cava D. Superior vena cava -> right atrium -> right ventricle -> pulmonary veins -> lungs -> pulmonary artery -> left atrium -> left ventricle -> aorta
Ventricular contractions (systolic) Ventricular relaxation (diastolic)
Blood pressure is expressed as a ratio of _____________________________ to ___________________________.
-The outermost layer of the heart. -Contains an inner and outer layer, with a gap filled with fluid separating them.
Describe the pericardium.
Pulmonary arteries Pulmonary veins
____________________________ delivers deoxygenated blood from the heart to the lungs, while _______________________ delivers oxygenated blood from the lungs to the heart.
Answer: C. The cardiac conduction system starts at the SA node, which is located near the top of the right atrium, and continues down to the AV node, which is located between the two AV valves. The bundle of His is located within the walls between the ventricles, and is likely to be affected if the wall between the ventricles has been damaged by a heart attack. This may affect the left ventricle, but the left ventricular muscle itself is not part of the cardiac conduction system.
A person has a heart attack that primarily affects the wall between the two ventricles. Which portion of the electrical conduction system is most likely affected? A. AV node B. SA node C. Bundle of His D. Left ventricular muscle
Pulmonary: Right ventricle Systemic: Left ventricle
What part of the heart is responsible for pumping blood through the pulmonary circulatory system? What about the systemic circulatory system?
-The innermost layer of the heart that lines the cavities of the heart. -The layer of heart muscles here is considerably thin.
Describe the endocardium.
-Atrioventricular valves snap shut -Semilunar valves open slightly after
Detail what occurs during the S1 sound in the heart.
It prevents the atrioventricular valves from flipping backwards, causing backwards flow of blood.
What is the purpose of papillary muscles and chordae tendineae in the heart?
Answer: C. An ordinary cardiac contraction originates in, and is regulated by, the sinoatrial (SA) node. The impulse travels through both atria, stimulating them to contract simultaneously. The impulse then arrives at the atrioventricular (AV) node, which momentarily slows conduction, allowing for completion of atrial conduction and ventricular filling. The impulse is then carried by the bundle of His and its branches through the Purkinje fibers in the walls of both ventricles, generating a strong contraction.
Which of the following is the correct sequence of a cardiac impulse? A. SA node -> AV node -> Purkinje fibers -> bundle of His -> ventricles B. AV node -> bundle of His -> Purkinje fibers -> ventricles -> atria C. SA node -> atria -> AV node -> bundle of His -> Purkinje fibers -> ventricles D. SA node -> AV node -> atria -> bundle of His -> Purkinje fibers -> ventricles
Atrioventricular: -Tricuspid valve -Mitral/Bicuspid valve Semilunar: -Pulmonary valve -Aortic valve
Which valves of the heart are classified as atrioventricular valves? Which valves of the heart are classified as semilunar valves?
The lungs has blood vessels on them that transports oxygenated blood to the tissue of the lungs, and vessels that transports deoxygenated blood back to the heart. These vessels are called bronchial arteries and bronchial veins respectively. There is also a lot of mixing of blood. Blood from pulmonary arteries and bronchial arteries actually mixes. Most blood transported through the pulmonary arteries actually gets transported back to the heart through the pulmonary veins. Not much blood flows back through the bronchial veins.
How do the lungs receive oxygen?
Sympathetic nervous system Parasympathetic nervous system
Signals from ________________________________ of the autonomic nervous system speeds up the heart rate and increases the contractility of cardiac muscles. Meanwhile, signals from _____________________________ of the autonomic nervous system slows down the heart rate and decreases contractility of cardiac muscles.
Answer: D. The atrioventricular valves are located between the atria and the ventricles on both sides of the heart. Their role is to prevent backflow of blood into the atria. The valve on the right side of the heart has three cusps and is called the tricuspid valve. It prevents backflow of blood from the right ventricle into the right atrium.
The tricuspid valve prevents backflow of blood from the: A. left ventricle into the left atrium B. aorta into the left ventricle C. pulmonary artery into the right ventricle D. right ventricle into the right atrium
Detect and regulate blood osmolarity.
What do chemoreceptors do in a blood vessel?
The elastin allows these arteries more elastic to resist higher pressures that will be acting on these vessels.
What is the purpose for large/medium arteries to contain elastin in their tunica media?
-Typical vessel structure -Tunica intima contains endothelial cells and a collagenous basement membrane -Tunica media contains a layer of smooth muscles -Tunica externa/adventitia consists of proteinous membrane.
Detail the structure of veins. (Be sure to include the three tunica layers)
-Smooth muscles -Sometimes elastin
What makes up the tunica media in a blood vessel?
Arteries are directly pumped by the left ventricle of the heart, while the veins are not directly pumped by the heart.
Why do arteries have higher pressure than veins?
-Semilunar valves snap shut -Atrioventricular valves open slightly after
Detail what occurs during the S2 sound in the heart.
Q = H * S Q = cardiac output in volume/minute H = heart beat in beats/min S = stroke volume in volume/beat
How is cardiac output calculated?
Opening of capillary beds (which are in parallel) will decrease the overall resistance of the circuit, which will result in the increase in cardiac output in order to maintain constant blood pressure. This is a risk to the heart because the increased demand on the heart can eventually tire it, leading to a heart attack, or a dramatic drop in blood pressure.
In bacterial sepsis (overwhelming bloodstream infection), a number of capillary beds throughout the body simultaneously opens. What effect would this have on blood pressure? Besides the risk of infection, why might sepsis be dangerous for the heart?
Systemic circulatory system
What part of the circulatory system are coronary vessels a part of?
Cardiac output
________________________ is the total blood volume pumped by the left ventricle in one minute.
Answer: B. The greatest amount of resistance is provided by the arterioles. Arterioles are highly muscular and have the ability to contract and dilate in order to regulate blood pressure.
Which vascular structure creates the most resistance to blood flow? A. Aorta B. Arterioles C. Capillaries D. Veins
The right side of the heart pumps blood into the lungs, which is a lower-resistance circuit compared to the systemic circulatory system, meaning that blood must be pumped at lower pressure, which requires less muscle.
Why does the right side of the heart contains less cardiac muscle than the left side?
It allows them to maintain sufficient pressure to pump blood when the ventricles relax.
Why is it important for large arteries to maintain a level of elasticity?
Atrial kick
_____________________ is the atrial systole that results in forcing a little bit more blood from the atria to the ventricles.
-Release chemicals that aid in vasodilation and vasoconstriction -Allow white blood cells to pass through a vessel and into tissue during an inflammatory response. -Release chemicals that promote clotting
What are some of the functions of endothelial cells in a blood vessel?
-Ventricles relax -Atria constricts -Semilunar valves close -AV valves open -Blood is pumped from the atria to the ventricles
What are the characteristics of the diastole phase of a heart beat?
-Ventricles contract -Atria relaxes -Semilunar valves open -AV valves close -Blood is pumped out of the ventricles
What are the characteristics of the systole phase of a heart beat?
Answer: C. The only answer choice that correctly describes arteries and veins is (C); the pressure in the aorta ranges between 120 and 80 mmHg, depending on whether the heart is in systole or diastole, whereas the pressure in the superior vena cava is near zero. (A) is incorrect because arteries are thick-walled and veins are thin-walled. (B) is also incorrect; this relationship is reversed in pulmonary and umbilical circulation. (D) is reversed as well; arteries make use of the pumping of the heart and the "snapping back" of their elastic walls to transport blood, whereas venous blood is propelled along by skeletal muscle contractions.
Which of the following is true regarding arteries and veins? A. Arteries are thin-walled, muscular, and elastic, whereas veins are thick-walled and inelastic. B. Arteries always conduct oxygenated blood, whereas veins always carry deoxygenated blood C. The blood pressure in the aorta is always higher than the pressure in the superior vena cava D. Arteries facilitate transport by using skeletal muscle contractions, whereas veins make use of the pumping of the heart to push blood
Right atrium - tricuspid valve Right ventricle - pulmonary valve Left atrium - mitral/bicuspid valve Left ventricle - aortic valve
Which valves prevents backflow into the following chambers of the heart? Right atrium Right ventricle Left atrium Left ventricle