Alterations in Cardiovascular System

The purposes of the circulatory system:

• Transports oxygen and nutrients 

• Circulates electrolytes and hormones to regulate function 

• Transports waste products from organs for elimination 

• Regulates temperature 

What is pulmonary circulation?

short system 

1. Movement of blood from the right side of the heart through the lungs in order to obtain oxygen from the lungs  

2. Anatomic structures 

• Right side of heart  

• Pulmonary artery 

• Pulmonary capillaries  

• Pulmonary veins 

3. ___Low____ pressure system allows blood to move more slowly through lungs for gas exchange:  Mean Arterial Pressure (MAP) = 12mmHg 

What is systemic circulation?

1. Transport of O2/nutrients to all cells/tissues of the body 

2. Anatomic structures 

• Left side of heart 

•  Aorta and all branches  

• Venous system  

• Vena cava 

3. High_pressure system:  Mean Arterial Pressure (MAP) = 90-100mmHg 

4. Blood flow through systemic circulation is driven by pressure difference between arterial and venous circulation 

____Atria______________: reservoir for blood returning from body and lungs; auxiliary pump for filling the ventricles 

__________Ventricles________________: main pumping chamber 

• Right to the lungs via the pulmonary artery 

• Left to the rest of the body via the aorta 

Closed system: both sides must pump the same amount of blood over time 

 

 

What are the atria?

reservoir for blood returning from body and lungs; auxiliary pump for filling the ventricles

What are the ventricles?

main pumping chamber 

• Right to the lungs via the pulmonary artery 

• Left to the rest of the body via the aorta 

What is the closed system?

both sides must pump the same amount of blood over time 

What is the flow of circulation in the heart?

 

Right atrium--- ___Tricuspid Valve____---- Right Ventricle--Pulmonic Valve--- Pulmonary Artery--- Pulmonary Vein ----Left Atrium---- Mitral valve----Left Ventricle---- Aortic Valve---- Aorta 

What is the covering around the heart that holds it in a fixed position and provides barrier for infection 

pericardium

What is the….

muscular portion;.

Each unit contracts as one; when one myocardial cell becomes excited, the impulse travels rapidly so the heart can beat as unit. 2 units: atria and ventricles 

myocardium

What is the thin membrane that lines the heart 

endocardium

What is the contraction of the ventricles called?

systole

What is the relaxation of the ventricles called?

diastole

Heart valves:

Atrioventricular (between atria and ventricles):

• Closed during systole_to prevent backflow of blood into atria:

  • Tricuspid_ & Mitral_

 

Semilunar (between ventricles and arteries):

• Closed during diastole to prevent backflow of blood into ventricles: _

  • Pulmonic___ & ___Aortic __ 

What is Closed during systole_to prevent backflow of blood into atria: Tricuspid_ & Mitral

Atrioventricular (between atria and ventricles):

What is Closed during diastole__ to prevent backflow of blood into ventricles: _Pulmonic___ & ___Aortic __ 

Semilunar (between ventricles and arteries)

What is the arterial system?

1. Arteries & arterioles: large & medium-sized thick walled & elastic—can stretch during systole & recoil during diastole 

2. 1/3 blood volume 

3. Carry oxygenated blood to all cells of body (except in pulmonic system—caries deoxygenated blood to lungs) 

4. Creates pulsations that are produced because of intermittent ejection of blood from left ventricle; Felt at multiple sites throughout the body which is called the ___pulse___ 

What is the large & medium-sized thick walled & elastic—can stretch during systole & recoil during diastole 

Arteries & arterioles:

What is the venous system?

1. Collects blood from capillaries and returns it to right atrium 

2. Thin-walled, distensible, collapsible vessels; able to store large quantities of blood 

3. Low-pressure system 

4. 2/3 blood volume—large reservoir 

5. Blood flows against gravity; valves prevent backflow; skeletal muscles surround veins and “milk” the blood back toward the heart 

What do valves prevent?

backflow

What kind of muscle surrounds veins and “milk” the blood back toward the heart?

skeletal muscles

What is being described here:

short term 

1. The ability of tissues to regulate their own blood flow: Determined by needs of the tissue 

2. Vasoactive substances (e.g. histamine, kinins, prostaglandins) play a role in affecting local control of blood flow to keep blood flow constant despite changes in blood pressure through changes in vessel tone 

autoregulation

What is being descibed here:

long term

1. If oxygen needs of a certain tissue are not being met, additional vessels will be formed (called angiogenesis) in order to increase blood flow to the tissue and meet the oxygen demands. 

2. A slow, progressive compensation to decreased blood flow to an area 

collateral circulation

What is angiogenesis?

If oxygen needs of a certain tissue are not being met, additional vessels will be formed

What is Humoral (hormone) Control

Vasoactive substances (e.g. RAAS, aldosterone, histamine, etc.) play a role in affecting local control of blood flow 

What is being described?

Vessels that travel alongside arterioles or venules and facilitate drainage of excess fluids, large particles, & proteins 

lymphatic system

What is microcirculation?

The capillaries, venules, and arterioles of the circulatory system 

 

Neural Control of Circulatory Function: 

Autonomic Nervous System (ANS): Control center located in medulla oblongata  

1. Chemoreceptors and baroreceptors located in the peripheral circulation keep the control center informed of changes in the blood pressure 

 

_Sympathetic__ Nervous System 

1. “fight or flight” 

2. Excitatory response (i.e. increase in heart rate/cardiac contractility & vasoconstriction) 

__Parasympathetic_ Nervous System 

1. “rest and digest” 

2. Regulates heart rate via the vagus nerve 

3. Inhibitory response (i.e. slowed heart rate) 

 

What is the

Control center located in medulla oblongata  

1. Chemoreceptors and baroreceptors located in the peripheral circulation keep the control center informed of changes in the blood pressure 

 

Autonomic Nervous System (ANS)

What is being described?

1. “fight or flight” 

2. Excitatory response (i.e. increase in heart rate/cardiac contractility & vasoconstriction) 

Sympathetic Nervous System

What is being described here?

1. “rest and digest” 

2. Regulates heart rate via the vagus nerve 

3. Inhibitory response (i.e. slowed heart rate) 

Parasympathetic Nervous System

What are the the principles of volume, pressure, flow, and resistance as they relate to circulatory system 

hemodynamics

Hemodynamics:

The circulatory system functions under optimal conditions if there is a sufficient _VOLUME____ to fill the vascular compartment and enough __PRESSURE_to facilitate blood flow to all tissues of the body.  

• ___Volume_______: amount of blood 

• ___Pressure______: pressure gradient moves blood from arterial to venous side 

  • Due in large part to structure and elasticity of arteries and veins  

• ____Resistance________: opposition of flow from friction between moving blood and stationary vessel wall 

• _____Flow________: represented by cardiac output; dependent upon the pressure difference between the two ends of a vessel and the resistance that blood must overcome as it travels through vessels. 

_______ : amount of blood

volume

What is the pressure gradient moves blood from arterial to venous side 

pressure

What is the opposition of flow from friction between moving blood and stationary vessel wall 

resistance

What is represented by cardiac output; dependent upon the pressure difference between the two ends of a vessel and the resistance that blood must overcome as it travels through vessels. 

flow

What is cardiac output?

The amount of blood (in liters) the heart pumps in 1 minute [4-8L/min] 

Cardiac output (CO)

• The amount of blood (in liters) the heart pumps in 1 minute [4-8L/min] 

• _____Stroke volume____ (SV): the amount of blood the heart pumps with each beat; dependent on  and afterload 

• _______Heart rate (HR)_______: how frequently the heart beats each minute 

• ______Cardiac output______ = Stroke Volume X Heart Rate [CO = SV X HR] 

• Ejection Fraction: % of blood that leaves heart with each beat (approx. 65-70%) 

What is the amount of blood the heart pumps with each beat; dependent on  and afterload 

Stroke volume (SV)

What is how frequently the heart beats each minute called?

Heart rate (HR)

what is the Stroke Volume X Heart Rate [CO = SV X HR] 

Cardiac output

What is ejection fraction?

% of blood that leaves heart with each beat (approx. 65-70%) 

The heart has ability to increase output based on body needs: 

• Preload

• Afterload

• Cardiac contractility

• Heart rate

What is preload?

• The pressure (amount of stretch) in the ventricles after filling up with blood; amount of workload imposed on heart before it begins contraction , 

•  A healthy heart can contract and have a stronger contraction with a good preload 

Example to remember preload

• If you think about a ballon, think about how when its blown up, that is the preload 

• Think about the stretch of a rubberband: 

  • if your stretching a rubber band and you don’t stretch it back very far, and you let it go its not going to go very far. But if you give it a good preload and you stretch that rubber band back pretty far, it will fly across the room

•  A healthy heart can contract and have a stronger contraction with a good preload 

What is Frank Starling’s Law

Increased stretch or preload (venous return) = increased force of contraction (stroke volume) when all other factors remain constant 

What is an example of an increased preload?

fluid volume overload                        

What is an example of Example of Decreased Preload

dehydration or hemmorage

• you don’t have as much fluid 

What is afterload?

Resistance to ejection of blood from the ventricles; The amount of pressure that the left ventricle must generate to force (eject) blood into the systemic circulation; Main source is arterial pressure for the left side of heart and pulmonary artery for right side  

What is an example of Increased Afterload:

hypertension and vasoconstriction 

What is an example of Decreased Afterload:

vasodilation and hypotension 

What is Cardiac Contractility 

The ability of the heart muscle (myocardium) to contract and change its force of contraction (inotropy) without any change in resting (diastolic) pressure. 

What is heart rate?

• Frequency of cardiac cycle; influences cardiac output and workload of the heart 

• The heart fills during diastole; increases in heart rate decrease the amount of time for filling 

  • if your heart has less diastolic time, because its beating faster you aren’t going to have as much filling time, you wont have as much cardiac perfusion and you’re also going to have a higher workload and higher oxygen consumption of the heart