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80 Cards in this Set
- Front
- Back
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How many times will the heart contract throughout the average human lifespan? |
It will contract 3 billion times - not stopping once, except for the time between beats. |
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When does the heart start beating in utero? |
It starts beating at three weeks - before the tim a woman can confirm that she is pregnant |
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Why does circulatory system develop early in an embryo? |
Circulatory system develops early because the embryo needs to be able to move nutrients and waste products early in development. |
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What does the heart do? |
It serves as a pump to move the blood throughout the body
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What do blood vessels do? |
They serve as passageways for the movement of the blood |
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Blood travels throughout the body in two vascular loops, which are |
1) Pulmonary circulation
2) Systemic circulation |
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Pulmonary circulation |
Vessels carrying blood between the heart and the lungs
*pulmonary = relating to lungs |
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Systemic circulation |
Vessels carrying blood between the heart and the other organ systems |
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How does blood distribute oxygen? |
Blood goes parallel through all the parts of the body, so that the distribution of oxygen is fair. |
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How many layers does the wall of the heart have? |
It has three layers: 1) Epicardium (outer wall) 2) Myocardium (myo - muscle; of the heart, contracts to create heartbeats) 3) Endocardium (inner) |
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Where does the heart reside? |
It resides in the center of thoracic cavity, surrounded by the pericardium |
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How many chambers does the heart have? |
The heart has four chambers: Two ventricles and two atria |
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Two ventricles |
- The muscular left ventricle pushes blood throughout the body
- The right ventricle pushed blood to the lungs. |
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Two atria |
Atria: smaller, thinner-walled chambers on top of the more muscular ventricles which:
- receive blood returning from the body/lungs through large veins
- hold the blood and then direct it into the ventricles |
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Pulmonary arteries carry ________ blood from the ___________ ventricle |
Pulmonary arteries carry deoxygenated blood from the right ventricle. |
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Two most important valves |
Right and Left Atrioventricular Valves (AV valves)
Right AV (Tricuspid) - has 3 leaflets Left AV (Bicuspid; Mitral Valve) - has 2 leaflets |
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Semilunar valves (2) |
1) Aortic Semilunar Valve (btw left ventricle and the aorta)
2) Pulmonary Semilunar Valve (btw right ventricle and pulmonary artery)
* semilunar because each leaflet is cup-shaped - like a half moon |
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What do heart valves do? |
They control blood flow |
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When does a valve open? |
When pressure is greater behind the valve, it opens.
-> P -> |
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When does the valve close? |
When pressure is greater in front of the valve, it closes.
* It does not open in the opposite direction; it is a one-way valve (Blood flows only in one direction)
P <- <- |
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Heart sounds can be heard with a |
Stethoscope |
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Normal heart sounds |
lubb-dupp |
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S1 "Lubb" |
a resonating sound caused by blood pressure against the atrioventricular valves (sound is the result of the closing of AV valves) |
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S2 "Dubb" |
a snapping sound when the ventricles relax and blood in the arteries flows back toward the ventricles (closing of semilunar valves) |
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Abnormal heart sounds - "murmur" occur |
- If the two ventricles are out of sequence, so that one closes first, S2 may "stutter" or "split"
- Murmurs may signal cardiovascular problems
- Murmurs can be benign: children often develop a murmur as they grow, because the cardiac muscle grows faster than the valves. |
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Blood flow through the heart |
Blood (oxygen poor) from Vena Cavae (large veins) enters the Right Atrium -> flows through the right AV valve into the Right Ventricle -> pumps it out through the Pulmonary Semilunar Valve to the Pulmonary Artery to the lungs.
The right side of the heart pumps blood from the Systemic circulation to the Pulmonary circulation.
Blood returns from the lungs (now oxygenated) and enters the Left Atrium via the Pulmonary Veins. From the Left Atrium the blood then flows through the mitral valve into the Left ventricle, which pumps the blood through the Aortic Semilunar Valve to the Aorta and then throughout the body.
The left side of the heart pumps blood from the Pulmonary Circulation to the Systemic Circulation.
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Do veins always carry de-oxygenated blood? |
Veins do not always carry de-oxygenated blood. Arteries do not always carry oxygen-rich blood.
* The distinction only occurs in the SYSTEMIC circulation. Just the opposite is true of the pulmonary circulation. |
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Cardiac Cycle |
The cycle of contraction and relaxation of heart
Diastole -> Atrial Systole -> Ventricular Systole
*Atrial systole (AV valves are open, SL valves are closed) *Ventricular systole (AV valves are closed, SL valves are open)
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Systole |
Contraction and emptying of the chambers |
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Diastole |
Relaxation and refilling of the chambers |
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Does blood volume change during the cardiac cycle? |
Blood volume DOES NOT change during the cardiac cycle, thus the force generated by the left ventricle results in a change in blood pressure from the relaxed state. |
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Blood pressure |
Blood pressure = systolic pressure/diastolic pressure (ex: 120/80mmHg)
* Normal blood pressure is ~ 90-120 (systolic) to 60-80 (diastolic). High blood pressure is ~ 140/90mmHg above *determined by sphygmomanometer |
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Systolic pressure |
the force with which left ventricle pushed blood through the circulatory system |
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Diastolic pressure |
the force the blood exerts on the walls of the circulatory system while the heart is relaxed |
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Laminar Flow |
Blood flowing smoothly (does not create any sound)
___________ __________ ____________ |
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Turbulent flow |
Blood flow restricted, it bounces around (creates sound as it hits the sides of the vessels) |
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The heart beat is under intrinsic and extrinsic controls |
Intrinsic: the controls within the heart that establish the normal pace of the heart
Extrinsic: signals from the rest of the body that modulate the baseline rate to meet the body's immediate demands |
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Intrinsic controls |
Cardiac muscle cells undergo contractions without receiving nerve impulses
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SA (sinoatrial) node |
A group of cells at the top of the right atrium that serves as the heart's pacemaker.
*SA node initiates the heartbeat by initiating an electrical signal that passes from cell to cell through the right and left atrium, causing both to contract. |
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AV (atrioventricular) node |
in the base of right atrium relays signal to the ventricles |
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Extrinsic controls |
Extrinsic controls can modulate the baseline heart rate to meet the body's immediate demands.
*The cardiac control center in the medulla oblongata can OVERRIDE the intrinsic heartbeat, increasing or decreasing the heart rate as necessary. |
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Electrocardiograms (ECGS) |
1) ECG is a recording of that portion of the cardiac signal that actually reaches the surface of the body - not the direct recording of the electrical activity of the heart.
2) ECG is the sum of the activity of many cells - not a single action potential in a single cell at a single point in time. |
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Three types of blood vessels |
- arteries - capillaries - veins |
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Walls of both arteries and veins have three layers |
- Endothelium (inner layer) - Smooth muscle and elastic tissue (in the middle layer) - Connective tissues (outside layer) |
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Arteries carry blood AWAY from the heart |
Arteries are blood vessels on the output (ventricular) side of the heart - arteries closest to the heart have the largest diameters and thickest walls.
*Arteriole = small vessel that branch from the arteries
*Blood flow slows as blood passes into progressively smaller diameter vessels |
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Capillaries are the UNITS OF EXCHANGE |
Arterioles lead to capillaries = the smallest blood vessels. - capillaries form networks called "capillary beds" - the wall of capillary is one cell layer thick - composed of endothelial cells
* In the walls of capillaries, there are gaps btw the endothelial cells -> pore formation - through which water and small, water-soluble molecules can enter or leave the capillary. |
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Bulk flow across capillaries |
Ultrafiltration & Reabsorption
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Ultrafilatration at the ARTERIOLE end |
High blood pressure in the capillaries forces water into the tissues. Large plasma proteins do not leave the blood as they cannot pass the pores. |
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Reabsorption at the VENULE end |
As blood passes through capillaries, the pressure drops and the osmotic pressure increases. Most of the water then flows back into the blood at the venous end of the capillary.
Osmotic pressure > Blood pressure |
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Veins bring blood back to the heart |
Blood leaving capillaries collects in large vessels called venules and veins heading back toward the heart.
Blood moves through the veins under lower pressure than the arteries.
Despite the low pressure, the blood continues to flow toward the heart - fluids flow more easily from a smaller vessel to a large one - venous valves prevent backflow of blood - skeletal muscles surrounding veins "push" blood toward heart |
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Types of heart disease |
Coronary heart disease: blocked/clogged arteries limit blood flow to the heart and starving of oxygen and nutrietns. Arrhytmia: the heart beats irregularly Heart failure: the heart can't pump as powerfully as it needs to in order to supply the body with oxygen and nutrients, causing the heart muscles to overwork and weaken. |
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Risk factors for cardiovascular disease |
genetic risk factors: - family history (before age 55) - gender (men>women) - ethnicity (AA>Caucasians) environmental risk factors (smoking, overeating, sedentary lifestyle) - 40 minutes a day of low-impact exercise can reduce the chance of heart disease by one-third. |
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High blood pressure (hypertension) |
One of the most prevalent CVDs (has no symptoms, stresses the entire body).
Hypertension is diagnosed when systolic blood pressure is above 140mmHG, or diastolic pressure is above 90mmHG - key risk is stroke - dietary restrictions, moderate exercise, reducing smoking and drinking, and medications can all control hypertension - a high diastolic number indicates that the blood-vessel elasticity has decreased, thus increasing the chance a systolic contraction will damage the circulatory system |
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Damage to the arteries |
Atheroscleroris ("hardened vessels") - plaques, fatty deposits of cholesterol, accumulate inside arteries and block the lumen, reducing blood flow (can cause clots to form):
thrombus: a clot attached to the artery wall embolism: a clot floating in the bloodstream - a floating clot can lodge in an artery, completely blocking blood flow and causing tissue death
Aneurysm occurs when an artery wall balloons under pressure, the weakened wall subsequently burst - burst aneurysms are usually fatal
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Stroke |
An embolism (blockage) or aneurysm (excess bleeding) in the brain causes stroke. Stroke results in a tissue of the brain starved of O2 and nutrients. - immediate effects: sudden difficulty speaking, blindness in one eye, and numbness and/or weakness, usually on one side of the body - long-term effects: stroke can also cause aphasia (loss of speech), loss of fine motor control, paralysis, or even death. - nearly 700, 000 Americans suffer a stroke each year
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Heart attack |
A heart attack, or myocardial infarction (MI), is the death of a portion of the heart muscle due to a lack of oxygen.
MI usually when clot in a coronary artery (branches off of the aorta) blocks the blood flow to a muscle. If the muscle dies, heart contractions will be compromised.)
Heart attack causes one in five deaths in the US
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Angina |
Angina occurs when the heart is deprived of oxygen temporarily (the heart tissue may act like a cramped muscle, causing a crushing radiating pain for the patient)
There are two forms of angina: - stable angina: can occur when the heart is working hard or when it is stressed - unstable angina: appears with no apparent stimulus and is often an early warning of impending heart attack. - could be treated with drugs (nitrate drugs relax smooth muscle in coronary arteries and thereby reduce blood pressure) |
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Surgical options to treat angina |
- balloon angioplasty (placement of a stent) - bypass surgery - heart transplant |
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Congestive heart failure |
Congestive heart failure is due to a weak heart - many hearts weaken over time and fail to push enough blood through the circulatory system - the blood backs up and leaks into the lungs or pools in the chest - increasingly common now that more people are living deep into old age.
Consequences: - fatigue - difficulty in breathing - tachycardia (rapid heart rate) - death (as fluids build up the lungs and drowns the respiratory membranes) |
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Varicose veins |
Varicose veins are distensions of the venous walls near valves - as the blood moves into the veins, it pools against the valves - if the walls of the vein are weak, the vein will expand and pop out of the musculature - the veins can be surgically removed |
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Spider veins |
Spider veins occur when venules fill with blood and do not empty - the veins can be flushed with saline |
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Blood is composed of |
Blood is composed of a liquid portion, the plasma, and a solid portion, the formed elements, which are mainly cells.
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What does blood do to maintain homeostasis? |
- it forms clots to prevent blood loss at injuries - the cells in the blood patrol the body to destroy pathogens - the plasma contains hormones, nutrients, and gases that need to be transported to specific areas of the body - it regulates the internal environment of the body by diffusing ions and other materials into the interstitial fluid - it transports heat btw the body core and the skin |
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What's plasma? |
Plasma is the liquid portion of the blood comprising 46-63% of total blood volume.
It's made up of 92% water, 7% dissolved proteins and 1% electrolytes, nutrients, and wastes.
proteins (albumin): maintain blood's osmotic pressure, so that water remains inside the vessels instead of diffusing into tissues electrolytes (ions): sodium and potassium nutrients: carbohydrates and amino acids wastes: urea, CO 2 and lactic acid. |
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Hematopoesis? |
Blood cell formation
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All the formed elements originate _______ |
From a common stem cell in the red bone marrow |
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WBC |
White blood cells (Leukocytes) defend the body against pathogens and other foreign substances |
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5 types of WBC |
Three types of granular cells: 1. neutrophils (neutral, pink) 2. eosinophils (pinkish orange) 3. basophils (basic, black) Two types of agranular cells: 4. lymphocytes (B cells: antibodies; T cells: pathogen recognition) 5. Monocytes (scavenger cells) |
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RBC |
Red blood cells (erythrocytes) are membrane bound sacs of hemoglobin that carry oxygen |
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Hemoglobin |
- each RBC contains ~200 mil hemoglobin molecules - each molecule contains 4 atoms of iron (heme) - hemoglobin picks up oxygen where O2 is high, and releases O2 where O2 is scarce - highly evolutionarily conserved
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RBC arise from ____________
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RBCs arise from reticulocytes (an immature red blood cell) |
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Do RBCs have nuclei? |
RBCs do not have nuclei and thus cannot repair themselves when damaged. - they circulate for ~120 days before they usually need to be removed from the circulatory system - the spleen and liver remove and recycle these cells ~ 2 mil RBCs are broken down p/sec - they need to be replaced at the same rate |
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Replacing RBCs |
the rate at which RBCs are replaced is controlled by hormones - low O2 in the blood stimulates the kidneys to make erythropoietin, a hormone that stimulates RBC production. |
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Abusing erythropoietin (EPO) |
can increase athletic performance "blood doping" legal: train at higher elevations to stimulate RBC production illegal: blood-transfusions and inject commercial erythropoietin
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Plasma contains agglutinins (antibodies) against the marker NOT found in RBCs |
-type A blood contains anti-B agglutinin that will clump B blood - these agglutinins can cause a severe reaction if the wrong blood is transfused into a patient - the presence/absence of agglutinins is used to type blood |
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Rh factor |
Rhesus factor is a protein that is either present Rh+ or absent Rh- |
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Blood thinners |
Blood thinners lower the possibility of blood clotting People with various heart disorders are prescribed warfarin bc it is effective at preventing new clots from forming -high doses of warfarin are toxic low doses of aspirin are recommended after a heart attack
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Anemia |
Anemia is a reduction in the red blood cell population and thus in the oxygen-carrying capacity of the blood. Symptoms: fatigue, weakness, shortness of breath, chest pains like angina
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Anemia is classified by the cause of the red blood cell deficiency |
Iron-deficiency anemia: a shortage of iron leads to fewer hemoglobin molecules for each RBC Pernicious anemia: a shortage of vitamin B12 inhibits RBC maturation Aplastic anemia: the bone marrow does not produce enough stem cells Excessive-bleeding anemia: serious injury reduces RBC counts Sickle cell anemia: an inherited disorder that misshapes the red blood cell, making it harder to pass through capillaries. |
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Blood disorders - CO poisoning |
Carbon Monoxide is an odorless lethal gas that prevents the blood from carrying oxygen to the tissues - CO molecules bond irreversibly to hemoglobin, RBCs contaminated with CO never regain functionality - The concentration of CO increases dramatically when fossil fuels are burned, for ex in the exhaust fumes of a car or from a gas-heating element - The first symptoms of CO poisoning are drowsiness and a headache |
