Chapter 13 (exam 3) Circulatory system
The septum is
- wall that Divides the right and left chambers of the heart
Anemia
-A condition in which the blood is deficient in red blood cells, in hemoglobin, or in total volume. POSSIBLE CAUSES OF ANEMIA: 1. Hemorrhagic (excessive bleeding would cause decreased red blood cells) 2. inadequate dietary intake (iron deficiency) 3. damage to bone marrow (aplastic) 4. abnormal hemoglobin (sickle cell anemia, thalassemia)
Conducting tissues of the heart
-Action potentials spread via intercalated discs (gap junctions). -SA node to AV node to stimulate atrial contraction (coordinate pumping) -AV node at base of right atrium and bundle of His conduct stimulation to ventricles. -In the interventricular septum, the bundle of His divides into right and left bundle branches. -Branch bundles become Purkinje fibers, which stimulate ventricular contraction. -Ventricles CONTRACT FROM BOTTOM UP
Mitral valve prolapse
-BLOOD FLOWS BACKWARDS
Heart sounds (lub/dub)
-This is caused by closing of the valves in the heart -"lub" is AV closing during ventricular systole -"dub" is SL closing during ventricular diastole
During systole (contraction)
-Ventricles are contracting -Semilunar valves are open -Blood is leaving the heart -AV valves are closed -Blood is flowing through semilunar valves
During Diastole (relaxation)
-Ventricles are relaxed -Semilunar valves are closed -Blood is entering the heart -AV valves are open -Blood is flowing through AV valves
Heart murmurs are due to
-abnormal blood flow to heart, defective heart valves, and this is congenital or acquired
Electrocardiogram (ECG) or (EKG)
-an electrical picture of the heart represented by positive and negative deflections on a graph labeled with the letters P, Q, R, S, and T, which correspond to events of the cardiac cycle -DETECTS ION MOVEMENT; DOES NOT RECORD ACTION POTENTIALS OR CONTRACTION AND RELAXATION -P wave: atrial depolarization -QRS wave: ventricle depolarization -T wave: ventricle repolarization
Formed elements: Red Blood Cells
-are flattened, biconcave in structure -function in oxygen transport; LOADED WITH HEMOGLOBIN -lack a nuclei and mitochondria and are the MOST ABUNDANT cell type -120 day life span
Blood composition
-avg adult has about 5 liters -color depends on how much oxygen is bound to hemoglobin -BRIGHT RED BLOOD IS OXYGEN RICH AND DARK BLOOD IS OXYGEN POOR
Atropine is a specific antagonist of muscarinic ACh receptors. It has many uses, including pupil dilation for eye exams. For what condition might it be used?
-bradycardia (slow heart rate) -explanation: since antagonist has opposite effect it would be used on a person slow heart rate so that heart rate would be increased
cardiac myocytes
-cardiac muscle cells -are connected by gap junctions (are intercalated discs)
Capillaries
-consist of a SINGLE SIMPLE SQUAMOUS EPITHELIUM -ARE VERY THIN -THIS IS WHERE gas, nutrient, and waste exchange occurs between blood and tissues -BLOOD FLOW IS REGULATED BY: vasoconstriction and vasodilation of arterioles
Erythropoiesis
-formation of red blood cells -regulated by Erythropoietin (EPO) hormone produced by the kidneys -EPO is produced by the kidneys to counteract hypoxia (low oxygen) -EPO targets red bone marrow to produce red blood cells which increases the oxygen carrying capacity of blood -As oxygen increases EPO production decreases (NEGATIVE FEEDBACK)
Formed Elements: Thrombocytes
-fragments of megakaryocyte found in bone marrow -DO NOT have a nucleus -Role is to help in blood clotting
Formed elements: Leukocytes (white blood cells)
-have nucleus and organelles -some do phagocytosis of bacterial cells (these cells are capable of amoeboid movement out of blood stream called DIAPEDESIS) -least abundant cell type in blood -lifespan is hours to years
Increasing K+ permeability ___ the membrane potential of a cell.
-hyperpolarizes
Arteries and veins (largest vessels) have multiple layers
-inner layer: endothelium -middle layer: elastic and smooth muscle -outer layer: fibrous connective tissue -LUMEN IS THE SPACE WHERE BLOOD IS -ARTERY HAS THICKER WALL due to the smooth muscle layer -VALVES are ONLY present in VEINS -CAPILLARIES ARE ONLY A SINGLE CELL LAYER THICK
ALL FORMED ELEMENTS
-originate from hematopoietic stem cells (present in red bone marrow)
The cardiovascular system is composed of two circulatory paths:
-pulmonary circulation, the circuit through the lungs where blood is oxygenated (It transports deoxygenated blood to the lungs to absorb oxygen and release carbon dioxide. The oxygenated blood then flows back to the heart.) -systemic circulation, the circuit through the rest of the body to provide oxygenated blood.
Blood Studies: Blood smear
-smear blood on a slide -views cell types and morphology -gives differential white count -IS A PHYSICAL EXAMINATION OF BLOOD
Hematopoiesis
-the formation of blood cells in the living body (especially in the bone marrow)
During ventricular systole, __________.
-the ventricles contract -the AV valves close -The SL valves open -blood flows through the aorta and the pulmonary trunk
Myocardial contractile cells
-these cells contract in order for systole and diastole to occur (contract in order for blood to flow) -have resting membrane potential of -85mV -the stimulus that gets contractile cells to reach threshold is an Action Potential from the SA node -depolarization is RAPID (Na+ influx) -there is a PLATEAU phase due to Ca2+ influx and then rapid repolarization as K+ channels open and Ca2+ channels close -the plateau phase slows down the course of the Action Potential
Stenosis is ___ Mitral stenosis is ___ Aortic valve stenosis is ___
-when calcified valve narrows, impairing blood flow -(mitral is left AV valve) this is when blood backs up and this causes pulmonary hypertension -(SL valve between left ventricle and aorta) this is when blood is not pumped out of the left ventricle and causes left ventricular hypertrophy -HEART MURMURS CAN BE CAUSED BY ALL OF THESE
Types of myocardial cells
autorhythmic and contractile
How would EPO doping increase athletic performance?
by increasing oxygen carrying capacity of the blood
Systole is ____ and Diastole is _____
contraction and relaxation
The right ventricle pumps _____ blood into the ____ circulation
deoxygenated; pulmonary
The oxygen content of blood in the aorta is ___ the oxygen content of blood in the pulmonary artery.
greater than
In an experiment, the vagus nerve, which carries autonomic signals to the heart, was cut. The investigators noticed that heart rate increased, and correctly concluded that ___ fibers in the vagal nerve ___ heart rate.
parasympathetic; slow
The semilunar valves close during __________.
ventricular diastole
Match the component of the heart with its description.1. Chambers of the heart that receive blood from the venous system 2. Chambers of the heart that pump blood into the arterial system 3. Separates the right atrium and ventricle from the left atrium and ventricle 4. Separates the atria from the ventricles
1. Atria 2. Ventricles 3. Septum 4. Fibrous skeleton
Match the abnormal heartbeat with the description of the ECG.1. ECG shows an abnormally slow heartbeat (less than 60 beats per minute) 2. ECG shows coordinated, rapid heartbeats (faster than 100 beats per minute) 3. ECG shows rapid, uncoordinated contractions 4. ECG shows rapid contractions (200-300 per minute)
1. Bradycardia 2. Sinus tachycardia 3. ventricular fibrillation 4. flutter
Match the event in the cardiac cycle with the corresponding component of an ECG.1. Ventricles depolarize and contract 2. Atria depolarize and contract 3. Ventricles repolarize and relax
1. QRS complex 2. P wave 3. T wave
Action potential in autorhythmic (pacemaker) cells
1. at -40mV voltage gated Ca2+ channels open and influx of Ca2+ causes depolarization 2. Voltage gated K+ channels open and cause repolarization -Autorhythmic cells DO NOT reach refractory period but for an instant and instantly the pacemaker potential begins rising again
Blood studies: Blood cell count
1. red cell count -anemia (is low count) and polycythemia (is high count) 2. White cell count -leukopenia (is low count) and leukocytosis (is high count) 3. platelet counts -thrombocytopenia (is low count) and thrombocytosis (is high count)
Match the description with one of the functions of the circulatory system. 1. Oxygen is carried from the lungs to the tissues. 2. Blood is diverted from deep to superficial vessels to cool the body. 3. Leukocytes fight disease-causing agents.
1. transportation 2. Regulation 3. Protection
How could this (ANEMIA) contribute to Jason's chronic fatigue?
A decrease in oxygen transport resulting in suppressed metabolism
Pathway of blood via systemic circulation
A,C,V,V -ARTERIES TO CAPILLARIES -CAPILLARIES TO VENULES -VENULES TO VEINS
What is the main plasma protein that helps pull water from the interstitial fluid into capillaries?
ALBUMIN
Jason's blood tests reveal that he has a low red blood cell count, hematocrit, and hemoglobin concentration. What condition do these test indicate?
ANEMIA
Blood plasma
-The pale yellow fluid portion of whole blood that consists of water and its dissolved constituents including, sugars, lipids, metabolic waste products, amino acids, hormones, and vitamins. -One dissolved protein is ALBUMIN (important for osmotic pressure of blood) -another dissolved protein is globulins (alpha and beta, are involved in transport of lipids and gamma are antibodies) -Fibrinogen (involved in blood clotting)
In what direction does blood flow through the heart?
-Blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. As the atrium contracts, blood flows from your right atrium into your right ventricle through the open tricuspid valve. -To be precise, Blood flows in both directions through the heart. Blood returning from the body enters the right side of the heart and exits on the left side. Blood returning from the lungs enters the heart on the left side and exits out of the top of the heart via the aorta. Blood also flows both up and down through the heart. Blood entering the heart moves into the right or left atrium, then descends into the right or left ventricle before leaving the heart through the top to either go to the lungs or to the rest of the body. -The right side of the heart pumps blood to the lungs to pick up oxygen. The left side of the heart returns the oxygenated blood to the rest of the body. The top of the heart (the atria) receives blood, and the bottom of the heart (ventricles) pumps blood out.
Veins
-Blood vessels that carry blood back to the heart -Have low pressure -have a thin wall and a large lumen, can collapse when cut -blood does NOT move by pressure through veins but by RESPIRATION, SKELETAL MUSCLE CONTRACTION AND VALVE PRESENCE (PREVENTS BACKFLOW)
Heart Arrhythmias detected by EKG (abnormal heart rhythms)
-Bradycardia: less than 60bpm (<60bpm) which is SLOW -Tachycardia: more than 100bpm (>100bpm) FAST
Cardiac muscle vs skeletal muscle
-CARDIAC MUSCLE CANNOT UNDERGO SUMMATION AND TETANUS LIKE SKELETAL MUSCLE
Pacemaker potential in autorhythmic cells
-DO NOT have resting membrane potential, instead they have pacemaker potential -largely the result of HCN channels; these channels are stimulated by hyperpolarization and cAMP -Voltage gated Na+/K+; open at -60mV -ARE CALLED THE FUNNY CURRENT BECAUSE THEY OPEN IN RESPONSE TO HYPERPOLARIZATION
myocardial autorhythmic cells
-Found in SA (sinoatrial) node which is in the right atrium and is the "pacemaker" -If something goes wrong with SA, there is secondary pacemakers in the AV node which are normally suppressed if the SA node is functioning -Secondary pacemakers fire less rapidly and if they were functioning as the primary pacemaker the person would have a lower heart rate -THESE CELLS DO NOT have resting membrane potential, instead they have pacemaker potential
Blood studies: Hemoglobin and Hematocrit (H&H)
-Hemoglobin are lysed (broken down) and density is measured -measures (hematocrit) or percent volume that red blood cells make up in whole blood
What will happen to cardiac output due to mitral valve prolapse?
-IT WILL DECREASE BECAUSE BLOOD FLOWS BACKWARDS (back into the left atrium instead of being ejected into the aorta.)
Structure of the heart:
-Located in mediastinum -Four chambers - left atrium and ventricle, right atrium and ventricle -Two atrioventricular valves, two semilunar valves -Three layers - epicardium, myocardium, endocardium -The two AV valves are located at the entrance into the ventricles. They are called the tricuspid valve and the bicuspid (mitral) valve. The tricuspid valve is located between the right atrium and the right ventricle; the bicuspid (mitral) valve is located between the left atrium and the left ventricle. -The semilunar valves are located at the exit of each ventricle at the beginning of the great vessels. They are known as the pulmonic valve and the aortic valve. The pulmonic valve is located at the entrance of the pulmonary artery as it exits the right ventricle. The aortic valve is located at the beginning of the ascending aorta as it exits the left ventricle. -Major Vessels: Vena cava, Pulmonary arteries (trunk), pulmonary veins, and aorta
Which statement about diastole is false?
-PRESSURE IN VENTRICLES IS GREATER THAN IN THE ATRIA -explanation: During diastole, the ventricles are relaxing. The drop in pressure means that SL valves will close, and AV valves will open. Pressure in the ventricles drops below that of the pressure in the atria.
A synthetic version of EPO is available and is widely used in dialysis patients. EPO doping to enhance athletic performance is prohibited by IOC and NCAA. What is the term for the abnormal cell count that would be associated with EPO doping.
-Polycythemia -explanation: polycythemia is increased red blood cell count. By increasing red blood cell count you increase oxygen carrying ability, thus increasing athletic performance.
Pulmonary circulation involves
-Pulmonary artery, pulmonary vein, right atrium, right ventricle, and lung capillaries
Formed Elements of blood plasma
-Red blood cells -Luekocytes (white blood cells) -Thrombocytes
Systemic circulation involves
-Superior/inferior vena cava, tissue capillaries, left ventricle and left atrium
Corlanor (ivabradine) is a cardiac drug that selectively blocks HCN channels in the heart in a dose dependent manner. For what medical condition might it be used?
-Tachycardia (fast heart beat)
Pacemaker potential (autorhythmic) PARASYMPATHETIC INNERVATION
-The neurotransmitter released is ACh (binds to muscarinic receptor) -Parasympathetic innervation decreases the heart rate -In response to ACh binding, K+ channels open and hyperpolarizes the cell which increases the time for pacemaker potential to reach threshold (this reduces heart rate and slows rate of action potential)
Pacemaker potential (autorhythmic) SYMPATHETIC INNERVATION
-The neurotransmitters released by fight or flight system is (E) Epinephrine or (NE) Norepinephrine -AUTORHYTHMIC CELLS HAVE BETA-ADRENERGIC RECEPTORS -Binding of (N) or (NE) to receptor protein stimulates the production of cAMP, increased cAMP activates HCN channels and results in increased Ca2+ entry and increased strength of contraction
Atrial contraction accounts for most of the ventricular filling.
FALSE
In the ventricles, the action potential travels from the top of the ventricles to the apex, causing the ventricles to contract.
FALSE -In the ventricles, the action potential travels down the interventricular septum to the apex and then superiorly through the Purkinje fibers into the ventricular walls.
The action potential travels quickly from the SA node to the AV node to allow both atria to contract together.
FALSE -The action potential travels slowly through the atria so that both atria can contract together.
The audible heart sounds are caused by contraction of the atria and ventricles.
FALSE -The heart sounds are caused by the closing of the two sets of valves THE SL AND AV VALVES, not the contractions of the heart's chambers.
What is the correct order of conduction through the heart's conduction system?
SA node, AV node, AV bundle, bundle branches, Purkinje fibers
In the heart, an action potential originates in the __________.
SINOATRIAL NODE (SA NODE)
Correct order of the cardiac cycle beginning with systole
SYSTOLE 1. Isovolumetric contraction (atria relaxed, ventricles contracted, AV valves closed) 2. Ejection (atria relaxed, ventricles contracted) DIASTOLE 3. Isovolumetric relaxation (atria relaxed, ventricles relaxed, SL valves closed) 4. rapid filling (atria relaxed, ventricles relaxed)
Cardiac cycle and pressure
SYSTOLE IN LEFT VENTRICLE 1st step: isovolumetric contraction (same volume); and pressure builds up and closes AV valves due to high pressure in ventricle and low pressure in atria 2nd step: Ejection; pressure built up in ventricles exceeds pressure in pulmonary trunk and SL valves open and blood escapes from heart and volume decreases DIASTOLE 3rd step: isovolumetric relaxation (same volume); a decrease in pressure causes SL valves to close (preventing back flow) 4th step: Rapid filling; pressure dropped because ventricles relaxed and AV valves open and as blood moves from atria into ventricles the volume increases 5th step: Atrial contraction (systole) forces more blood into the ventricles (volume increases)
When the pressure in the ventricles becomes lower than the pressure in the atria, __________.
THE AV VALVES OPEN
Where do action potentials originate in the heart?
THE SA NODE (Action potentials originate in the SA (sinoatrial) node in the right atrium of the heart. This is the natural pacemaker.)
Dialysis patients may need synthetic EPO because damaged or diseased kidneys may not produce adequate amounts of erythropoietin.
TRUE
Cardiac cycle
The heart pumps oxygenated blood out of the left ventricle and into the aorta to begin systemic circulation. After the blood has supplied cells throughout the body with oxygen and nutrients, it returns deoxygenated blood to the right atrium of the heart. The deoxygenated blood shoots down from the right atrium to the right ventricle. The heart then pumps it out of the right ventricle and into the pulmonary arteries to begin pulmonary circulation. The blood moves to the lungs, exchanges carbon dioxide for oxygen, and returns to the left atrium. The oxygenated blood shoots from the left atrium to the left ventricle below, to begin systemic circulation again.
Arteries
two types: 1. elastic arteries -closest to the heart -stretch and recoil with systole and diastole 2. muscular arteries -farthest from heart -are more smooth muscle -have more resistance (smaller lumen)
