Chapter 11b Part 1 – Cardiovascular Physiology

1. Structure of hearta. Heart location

i. Anterior medial sternum In thoracic cavity between lungsb. 4 chambers

i. 2 atria left and rightii. 2 ventricles left and right

1. Left ventricle is largest and strongest chamber in hearta. Have enough force to push blood through aortic valve into entire body

c. Large blood vessels from right to left sidei. Superior and inferior vena cava ii. Aorta

iii. Pulmonary artery pulmonary trunkiv. Pulmonary veins (right and left side)

d. Septumi. Wall of muscle which separates left and right atria and left and right ventricle

e. Posterior region of hearti. Has 4 pulmonary veins

1. 2 right pulmonary veins 2. 2 left pulmonary veins

f. Layers of the hearti. Pericardium thin membrane that covers heart covered by pericardium

1. Underneath pericardium we have fat tissueii. Myocardium muscle which is underneath fat tissue

1. Thickest layeriii. Endocardium inside wall of heart

g. Trabeculae carneaei. Muscular columns which project from inner surface of right and left ventricle

h. Papillary muscle 3 in right ventricle and 2 on left ventriclei. Each papillary connected to chordae tendineae in right (3 chordae tendineae) and in left (2

chordae tendineae)1. Chordae tendineae Ligaments which connect papillary muscle to AV valve

i. Chordae tendineae connect AV valves (atrioventricular valves) to papillary musclesi. In ventricles

j. Heart Valvesi. 4 types of valves

1. Tricuspid valve (tri for 3 papillary muscle in right ventricle)a. Controls blood flow between right atrium and right ventricle

2. Pulmonary valvea. Controls blood flow from right ventricle to pulmonary arteries

i. Pulmonary arteries carry blood to your lungs and pick up O2

ii. Pulmonary veins take blood from lungs to left atrium

3. Bicuspid valve (mitral valve) (bi for 2 papillary in left ventricle)a. Controls flow of oxygen-rich blood from left atrium to left ventricle

4. Aortic valvea. Controls flow of oxygen-rich blood from left ventricle to the rest of the bodyb. Body’s largest artery

2. Circulation of Blood a. General Circulation

i. Superior and inferior vena cava1. Superior and inferior vena cava collect deoxygenated blood (contains CO2) from

different parts of body. a. Superior vena cava blood from head and upper extremitiesb. Inferior vena cava blood from abdomen and lower extremities

2. Release content into right atriumii. Right atrium

1. By contraction of right atrium, the blood is released into right ventricle through tricuspid valve

2. Then by contraction of right ventricle, the blood is ejected into pulmonary arteryiii. Pulmonary artery

1. 2 Pulmonary artery carries deoxygenated blood to lungsa. 1 right pulmonary vein takes blood to right lung

b. 1 left pulmonary vein takes blood to left lungiv. Lung

1. Lung tissue receives deoxygenated blood by pulmonary artery 2. Then lung has gas exchange or diffusion where is uptakes CO2 (breathed out) and

releases oxygen into pulmonary capillaryv. Pulmonary veins

1. 4 pulmonary veins take fresh oxygenated blood from lung to left atriuma. 2 right pulmonary veins carry blood from right lung to heartb. 2 left pulmonary veins carry blood from left lung to heart

vi. Left atrium1. By contraction of left atrium, fresh oxygenated blood is released into left ventricle

through bicuspid valve (also called mitral valve)vii. Left ventricle

1. By contraction of left ventricle, blood is ejected into aorta viii. Aorta

1. Aorta carries fresh blood to different part of body such as head, neck, and upper extremities and lower part of body (abdomen and lower extremities)

2. Aorta is mother of arterial system and largest artery in bodyb. Two types of circulation

i. Systemic circulation between organs (body) and heart1. Superior and inferior vena cava take blood from body to heart2. Aorta takes blood from heart to different parts of body

ii. Pulmonary circulation between lungs and heart1. Pulmonary artery takes blood from heart to the lungs2. Pulmonary veins take blood back from lungs to the heart

3. Hemodynamics dynamics of blood flowa. Blood flow

i. Aorta arteries arterioles capillary venules large veins (Inferior and superior vena cava)

b. Components of vasculaturei. Arteries (carry blood away from heart)

1. Deliver oxygenated blood to tissues2. Smooth muscle in wall

a. Under control of ANS (sympathetic system mostly)b. Contain alpha 1 adrenergic receptors

i. Alpha 1 vasoconstrictionii. Controls blood pressure

3. Volume of blood in arterya. Under high pressure because it comes from ventricular contraction (stressed

volume)b. When ventricle contracts, blood flows to arterial system so volume of blood

that exists in arterial system is under pressure called stressed volume4. Wall of artery

a. Thicker than veini. Thickness of wall due to elastic fiber which occupies internal

environment of artery.5. Blood in artery

a. Amount of blood in artery is a little bit less than venous system b. This is due to wall of artery being thicker and occupying more internal space

6. Pressure in arterya. Much higher than venous system

ii. Arterioles1. Smallest branches of arteries2. Have smooth muscle controlled by ANS and alpha 1 receptors

iii. Capillary1. Lack of smooth muscle in wall 2. Contains pores for gas exchange, nutrients, fluid absorption and excretion

iv. Venules1. Formed from merged capillaries

v. Veins (carry blood to heart)1. Wall of vein has smooth muscle which is under control by sympathetic system.

a. Controlled mostly be alpha I adrenergic receptor. 2. Wall of vein

a. Thinner than artery 3. Pressure in vein

a. Pressure is much lower than artery

b. The blood flow is due to skeletal muscle contraction and having valve inside the vein.

i. Valves show direction of blood flowc. Have unstressed blood volume

c. Pressure in vasculaturei. Pressure that exists in aorta and arteries comes from ventricular contraction (left). ii. Aorta 100 mmHg

1. Aorta has bigger diameter but higher pressure which is about 100 mmHg. iii. Artery and arterioles 50 mmHg

1. When blood flow reaches artery and arterial, these parts have smaller diameter than aorta, and for that reason, it shows resistance to blood flow and blood pressure decreases to 50 mmHg.

iv. Capillary 20 mmHg1. When blood flow reaches capillary, diameter is smaller than arterial and artery.

Because of intersectional area and smaller diameter, blood pressure drops to 20 mmHg.

2. Total peripheral resistance (TPR) is what capillaries are called (TPR builds up high pressure in aorta.)

v. Veins and Venules 4 mmHg1. When blood pressure reaches to venous or venal system and large veins the

pressure becomes 4 mmHg (in vena cava)d. Velocity of blood flow

i. Depends on…1. Diameter of blood vessels2. Intersectional area which exists in capillary

e. Blood flowi. Depends on…

1. TPR – total peripheral resistancea. Higher TPR means less flow

2. Pressure depends on different parts of blood vessel ii. Pressure gradient drives blood flow through circulatory system

iii. Blood flows from high pressure to lowf. Resistance to blood flow

i. Depends on….1. Radius and diameter of blood vessel

a. Smaller diameter means higher resistance2. Viscosity (concentration) of blood

a. More concentrated (higher hematocrit) means higher viscosity and higher resistance

3. Length of blood vessels a. Participate in resistance of blood vessels to blood flow

g. Capacitance of blood vessels (capacity of blood vessel amount of blood it can hold)

i. Depends on elastic fiber in wall of blood vesselsii. Higher elasticity means lower capacitance

1. This is because more elastic fiber in walls of vessel fills up internal space of vessel so it can’t carry as much blood

iii. Elastic fiber is found more in artery than venous system1. This means that the capacitance of arteries is less than veins

a. Wall of artery is thicker than vein because it has more elastic fiber. b. This makes it occupy internal environment of artery. c. For that reason, the amount of blood that exists in artery is a little lower than

venous system because wall of vein has less elastic fiber and thus has a thinner wall.

iv. Capacitance and pressure are inversely proportional1. Artery lower capacitance so higher pressure2. Vein higher capacitance so lower pressure

a. Venous pressure is higher than atrium or atrial pressure (atria of heart) because atrium shouldn’t show any resistance to venous system so it can receive large amounts of blood from veins (blood flows from higher pressure (veins) to lower pressure (atria))

b. Superior and inferior vena cava on right and 4 pulmonary veins (2 on right side and 2 on left side)

h. Blood pressurei. Pressure that exists on the wall of blood vessels by blood flowii. Controlled by contraction and relaxation of ventricles ANS (autonomic nervous system)

iii. Hypertension 1. Any factor that leads to (1) constriction, (2) obstruction, or (3) destruction of blood

vessels leads to hypertension.a. (1) Constriction

i. From overstimulation or over secretion of NE which stimulates alpha I adrenergic receptor

1. Alpha 1 for vasoconstriction which increases blood pressure and causes hypertension

b. (2) Obstructioni. From accumulation of lipids or calcium underneath blood vessel wall

1. This causes buildup to occupy internal environment of blood vessels and increases blood pressure

c. (3) Destructioni. Congenitalii. Destruction of blood vessel wall due to excess calcium called

hypercalcemia 1. This calcification causes wall of blood vessel to become rigid

and tough and destroys itiii. Accumulation of glucose

1. Hyperglycemia leads to vasculopathy destruction of wall of blood vessels

a. Could be destruction can be renal artery (renal failure), coronary artery (myocardial infarction), or any other artery

iv. Hormonal disorder1. Excess of some hormones can lead to overactivation of alpha I

adrenergic receptor. Some hormones are…a. Thyroid hormone (T3 or T4 from thyroid gland)b. Cortisolc. Aldosteroned. Prostaglandin (causes vasoconstriction), e. NE and adrenaline. f. Increases in any of these hormones can lead to

hypertensionv. Physiological conditions

1. Pregnancya. Pregnant females have hormonal change which affects

blood vessel wall and it can cause temporary hypertension

4. Arterial pressurea. Blood pressure (BP) is a force exerted by circulating blood on the walls of blood vesselsb. Blood is not constant during cardiac cycle. It is pulsatile (changes)c. Systolic pressure

i. Highest arterial pressureii. Pressure that exists in ventricle during ventricular contractions (systole)

d. Diastolic pressurei. Lowest arterial pressureii. Pressure that exists in ventricle during relaxation phase (diastole)

e. Pulse pressurei. Difference between systolic and diastolic pressureii. Arterial pressure is higher than venous, venous is higher than atrial pressure

f. Mean arterial pressurei. Approximately diastolic pressure + one third of pulse pressure