Structure and Function of the Cardiovascular System
Apply the variables identified in Poiseuille's formula to normal blood flow and blood flow resistance
According to Poiseuille's law, a five-fold increase in blood pressure would be required if the increase were supplied by blood pressure alone! But the body has a much more potent method for increasing volume flowrate in the vasodilation of the small vessels called arterioles.
Identify the four heart valves, and discuss their basic function.
1- Open tricuspid and mitral valves Blood flows from the right atrium into the right ventricle through the open tricuspid valve, and from the left atrium into the left ventricle through the open mitral valve. 2- Closed tricuspid and mitral valves When the right ventricle is full, the tricuspid valve closes and keeps blood from flowing backward into the right atrium when the ventricle contracts (squeezes).When the left ventricle is full, the mitral valve closes and keeps blood from flowing backward into the left atrium when the ventricle contracts. 3-Open pulmonic and aortic valve As the right ventricle begins to contract, the pulmonic valve is forced open. Blood is pumped out of the right ventricle through the pulmonic valve into the pulmonary artery to the lungs.As the left ventricle begins to contract, the aortic valve is forced open. Blood is pumped out of the left ventricle through the aortic valve into the aorta. The aorta branches into many arteries and provides blood to the body. 4- Closed pulmonic and aortic valves When the right ventricle finishes contracting and starts to relax, the pulmonic valve snaps shut. This keeps blood from flowing back into the right ventricle.When the left ventricle finishes contracting and begins to relax, the aortic valve snaps shut. This keeps blood from flowing back into the left ventricle. This pattern is repeated, causing blood to flow continuously to the heart, lungs, and body. The four normally working heart valves make sure blood always flows freely in one direction and that there is no backward leakage.
Compare and contrast the atrioventricular and semilunar valves.
> Atrioventricular valves (AV)- 2 types 1: The mitral valve 2: The tricuspid valve -Between the upper chambers and lower chambers (artia, ventricles) -Prevent backflow of blood from the ventricles into the atria during ventricular emptying -Blood flow from the atria into the ventricles during ventricular filling >Semilunar valves - 2 types 1: The aortic valve 2: The pulmonary valve -Are in the arteries leaving the heart -SV are between ventricles and arteries
Define systole and diastole.
>Diastole and systole are two phases of the cardiac cycle. They occur as the heart beats, pumping blood through a system of blood vessels that carries blood to every part of the body. >Systole occurs when the heart contracts to pump blood out, and diastole occurs when the heart relaxes after contraction.
Relate the structures of the heart to the phases of the cardiac cycle.
-In the cardiac cycle the heart is going to contract and fill. -The depolarization would start in the SA node which is in the right and left atrium. -This would travel into the AV node, in the right atrium. -The AV bundles (bundle of his) would travel down in between the right and left ventricles down to the apex. -They would then distribute up the right and left ventricles closer to the endocardium.
Compare structures of the heart associated with the pulmonary circulation and the systemic circulation.
-Pulmonary Circulation: Pulmonary circulation carries deoxygenated blood from the right ventricle of the heart to the lungs through the pulmonary artery. -Systemic Circulation: Systemic circulation carries oxygenated blood from the left ventricle of the heart to the rest of the body by the aorta.
Compare the structure and function of arteries and veins.
Arteries carry blood away from the heart, and veins carry blood towards the heart.
Identify the different types of blood vessels in the body; describe their connections to each other.
Arteries: Transport oxygenated blood from the heart to body tissue. Veins: Transport deoxygenated blood from the body to the heart. Capillaries: Small blood vessels, they connect both arteries and veins, and make the place for molecules exchange transporting nutrients, blood and Co2 through the body.
Identify the four heart chambers; describe the blood flow in and out of these chambers.
Atria - upper chambers Right atrium -Receives Venous blood from body -Pushes blood to Rt ventricle through tricuspid valve -Incoming blood supply -Superior vena cava, inferior vena cava, coronary sinus -Blood goes from right atrium, through tricuspid valve to go to the left ventricle. Left atrium -Receives oxygenated blood from lungs -Pushes blood to Lt ventricle through Bicuspid valve -LA - LV via bicuspid. Ventricles - lower chambers Right ventricle -Pushes blood only to lungs -Contains deoxygenated blood -Blood passes from RV to pulmonary valve via a large artery called the pulmonary trunk (PA) Left ventricle -Oxygenated blood -Pushes blood to entire body except lung -Blood passes from the LV through the aortic valve into the ascending aorta -Then coronary arteries supply heart with blood -Remaining blood passes into the arc and descending aorta
Describe the function of collateral arteries in coronary circulation.
Collateral circulation is a network of tiny blood vessels, and, under normal conditions, not open. When the coronary arteries narrow to the point that blood flow to the heart muscle is limited (coronary artery disease), collateral vessels may enlarge and become active.
Relate mean arterial pressure to the maintenance of tissue perfusion. Pressure promotes perfusion to the tissues to increase blood delivery to the tissues
Consequently, MAP can be used to evaluate CO and tissue perfusion. That is why some studies revealed that an MAP of about 60 mmHg was the critical low limit of organ perfusion. When MAP is more than 60 mmHg, increasing the level of MAP can lead to better organ perfusion particularly (Hollenberg et al., 2004
Characterize the blood flow in the coronary circulation; relate the blood flow to the metabolic needs of the heart.
DETERMINANTS OF CORONARY BLOOD FLOW. Under normal conditions, there are four major determinants of coronary blood flow: perfusion pressure, myocardial extravascular compression, myocardial metabolism, and neurohumoral control.
Compare the effects of the skeletal muscle and respiratory pumps on venous pressure and venous return.
During upright posture, skeletal muscles help maintain venous return and consequently cardiac output by compressing underlying veins in order to increase blood flow back to the heart (skeletal muscle pump).
Explain variation in the heart rates of children, normal adults, and highly trained athletes. Just know differences exist and how they are different; what is normal heart rate?
Endurance athletes often have a lower resting heart rate than others. Heart rate is measured in beats per minute (bpm). Your resting heart rate is best measured when you're sitting or lying down, and you're in a calm state. The average resting heart rate is usually between 60 and 80 bpm
Describe the structure and function of the three layers of the blood vessels.
Epicardium: Outer layer: connective tissue, adheres topericardium. Myocardium: Middle layer: thick muscle, makes up most of the heart mass. Endocardiom: Inner layer: Smooth muscle and elastic fibers: lines the chanbers, valves and vessels: continuous with inner lining of blood vessels
Discuss \four unique characteristics of the myocardial cells and the conduction system: automaticity, rhythmicity, conductivity, and contractility.
Here are five main characteristics of mature cardiomyocytes: (1) striated; (2) uninucleated; (3) branched; (4) connected by intercalated discs; (5) high mitochondrial content.
Apply the Frank-Starling Law of the Heart to demonstrate the interrelationship among preload, afterload, and contractility in the determination of cardiac function.
If the law states that the End Diastolic Volume is proportional to the Stroke Volume, then preload, afterload, and contractility are together proportional to said volume, given that these factors influence the Stroke Volume.
Compare laminar and turbulent blood flow
Laminar flow is characteristic of a healthy artery such as the femoral artery. Turbulent flow describes a situation where the flow pathway becomes disorganized, layers break formation, and eddy currents are formed.
Compare and contrast the effect of positive and negative inotropic agents on heart contractility and stroke volume.
Positive inotropes increase contractility, increasing stroke volume Negative inotropes decrease contractility, decreasing stroke volume
Compare preload and afterload.
Preload = Degree of stretch Afterload = Combined load of EDV and arterial resistance during ventricular contraction
Explain the relationship of pressure and resistance on blood flow.
Presure allow the blood flow to go in and out of the heart to the lungs or to the body, pushing a consistance of blood traveling trhough the vessels to arrive its destinations. While the blood process is carried out, the pressure will decrease little by little the further it is from its initial point. The decrease in presure allows to the blood to come back from the right side of the heart to the left side of the heart. Resistance is a something the vessels apply to slow blood flow when necesary. If resistance increases, either pressure must increase to maintain flow, or flow rate must reduce to maintain pressure.
Describe the effects of epinephrine, antidiuretic hormone, natriuretic peptides, and renin on blood pressure.
Renin: is released when our blood pressure is too low. Epinephrine/NE: Both substances play an important role in the body's fight or flight response, and their release into the bloodstream causes increased blood pressure, heart rate, and blood sugar levels. Antidiuretic hormone: Higher concentrations of anti-diuretic hormone cause blood vessels to constrict (become narrower) and this increases blood pressure. A deficiency of body fluid (dehydration) can only be finally restored by increasing water intake. Natriuretic peptides are commonly considered cardiovascular and renal hormones. Indeed, genetic natriuretic peptide deletion promotes arterial hypertension and associated organ damage. Conversely, pharmacological natriuretic peptide augmentation lowers blood pressure
Describe the Bainbridge and baroreceptor reflexes.
The Bainbridge reflex and the baroreceptor reflex act antagonistically to control heart rate. The baroreceptor reflex acts to decrease heart rate when BP rises. When blood volume is increased, the Bainbridge reflex is dominant; when blood volume is decreased, the baroreceptor reflex is dominant.
Define vascular compliance; apply compliance to structural changes in the vasculature.
The ability of a blood vessel wall to expand and contract passively with changes in pressure is an important function of large arteries and veins. Compliance of a vessel is the amount by which it will increase in volume for a given increase in distending pressure and is determined by the elastic properties of the vessel wall.
Identify the location and function of the cardiovascular control center; compare the cardioinhibitory and cardioexcitatory centers.
The cardiovascular center is a part of the human brain found in the medulla oblongata, responsible for regulation of cardiac output. Numerous receptors in the circulatory system can detect changes in pH or stretch and signal these changes to the cardiovascular center. The cardioaccelerator center stimulates cardiac function by regulating heart rate and stroke volume via sympathetic stimulation from the cardiac accelerator nerve. The cardioinhibitor center slows cardiac function by decreasing heart rate and stroke volume via parasympathetic stimulation from the vagus nerve
Describe the structure and function of myocardial cells; identify the role of intercalated disks.
The myocardial cells are in the myocardium (middle layer) of the heart. They help with the action of pumping blood into the heart. An intercalated disk would help with the communication between the cells. This will also allow them to send signals to each other.
Characterize the three layers of the heart wall.
The outer layer of the heart wall is the epicardium, the middle layer is the myocardium, and the inner layer is the endocardium.
Discuss the structural and functional differences between the right and left sides of the heart.
The right side of your heart receives oxygen-poor blood from your veins and pumps it to your lungs, where the blood picks up oxygen and gets rid of carbon dioxide. The left side of your heart receives oxygen-rich blood from your lungs and pumps it through your arteries to the rest of your body.
Characterize the effects of atrial receptors, hormones, and biochemicals on vasculature and heart function. Don't need to memorize all; need to know differences in sympathetic and parasympathetic activation and what hormones do this
The sympathetic nervous system (SNS) releases the hormones (catecholamines - epinephrine and norepinephrine) to accelerate the heart rate. The parasympathetic nervous system (PNS) releases the hormone acetylcholine to slow the heart rate.
Describe the physiology of sympathetic and parasympathetic stimulation on the heart.
The sympathetic nervous system (SNS) releases the hormones (catecholamines - epinephrine and norepinephrine) to accelerate the heart rate. The parasympathetic nervous system (PNS) releases the hormone acetylcholine to slow the heart rate.
Describe the function of the pericardium.
Thin sac that surrounds the heart and protects and lubricates within the chest. Fibrous pericardium: -Dense outer layer of connective tissue -Prevents overstretching -Anchors heart to mediastinum Serous pericardium: -Outer layer bound to fibrous pericardium -Inner layer fused to epicardium -Helps adhere to surface of the heart c) Can become inflamed and filled with fluid
Relate the following to normal heart function: myosin, actin, troponin and troponin-tropomyosin complex.
Tropomyosin blocks myosin binding sites on actin molecules, preventing cross-bridge formation, which prevents contraction in a muscle without nervous input. The protein complex troponin binds to tropomyosin, helping to position it on the actin molecule
