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59 Cards in this Set
- Front
- Back
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Heart and blood vessels of the body are arranged in two circuits ? |
1. Pulmonary circulation 2. Systemic circulation |
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Pulmonary circulation is? |
Movement of deoxygenated blood through blood vessels from the right side of the heart to the lungs and movement of oxygenated blood from the lungs to the left side of the heart |
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Describe the process ? |
- purpose is to oxygenate the blood and remove carbon dioxide - deoxygenated blood leaves the RV via pulmonary trunk which branches into the right and left pulmonary arteries that carry blood to each lung - exchange of gases takes place in the lungs - 4 pulmonary veins returning oxygenated blood to the LA of the heart |
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System circulation is ? |
Movement of oxygenated blood through the left side of the heart to the entire body (systemic cells) exchange of nutrients, gases and wastes and the return of blood to the right side of The heart |
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What is the purpose of systemic circulation ? |
Is to carry oxygenated blood from the heart to the body cells and deoxygenated blood back to the heart |
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What is the basic pattern of blood flow steps? |
1. Right side of the heart deoxygenated blood 2. Left and right lungs deoxygenated blood and returns the blood back to the left side of the heart and turns to oxygenated blood 3. Left side of the heart oxygenated blood 4. Systemic cells |
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Where is the heart located? |
In the mediastinum within the thoracic cavity, bordered laterally by the lungs and posteriorly by the vertebral column and anteriorly by the sternum |
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The heart is ? |
the size of their closed fist and is pointed at one end, the apex rests on the diaphragm and the base lies superiorly where the great vessels attach to the heart |
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Landmarks of the heart? |
Heart has 4 chambers left and right atrium and right and left ventricles |
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The atria is? |
Superior chambers, have thin muscular walls and are highly expandable and receive blood from the lungs and the body. The expandable extensions are called auricles |
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The ventricles are? |
Lower chambers, pump blood into blood vessels which leave the heart - right side of the heart contains oxygenated blood receives from all organs. Versus the left side the heart contains deoxygenated blood and receives from the lungs |
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The septum ? |
Is the partition between the right side and left side of the heart |
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Interatrial septum? |
Is the partition between the Atria |
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In the utero ? |
There is a opening in the interatrial septum of the fetal heart, foramen ovale, allows blood to flow from the right atrium to the left |
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Fossa ovalis? |
At birth the foramen ovale closes and forms a pale coloured depression |
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Interventricular sulcus ? |
Is the partition between the ventricles |
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Coronary sulcus ? |
Is the deep groove which encompasses the heart and separates the atria from Rh e ventricles |
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The coronary vessels are located? |
Within the inter-ventricular and coronary sulci |
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Right atrium internal structures ? |
- Muscular ridges called pectinate muscles - fossa ovalis, oval depression in the interatrial septum - contains openings of three blood vessels: coronary sinus, superior and inferior Vena cava - contains the right atrioventricular valve |
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Right ventricle internal structures ? |
- contains large muscular ridges called traveculae carneae - three muscular projections called papillary muscles help anchor chordae tendineae to the atrioventricular valve - superior part narrows into the pulmonary semilunar valve |
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Left atrium internal structures ? |
- contains pectinate muscles - contains openings of the pulmonary veins - contains the left atrioventricular valve |
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Left ventricle internal structure? |
- contains trabeculae carneae - two papillary muscles anchored by chordae tendineae - contains opening of the aorta - contains the aortic semilunar valve |
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The heart has 4 valves within the heart which function to prevent backflow of blood, which are? |
1. Atrioventricular cuspid - between the atria and ventricles. The valves that leave the ventricles have 3 cusps and are called semilunar valves. 2. Tricuspid valve - separates the right atrium from the right ventricle 3. Pulmonary valve - where the pulmonary trunk leaves the right ventricle 4. Bicuspid (mitral) valve - separates the left atrium from the left ventricle (left atrioventricular valve) - Aortic valve where the aorta leaves the left ventricle - Cuspid Valves attach to the ventricular side via fibrous strings called chordae tendineae |
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Muscle cells |
Muscle tissue - short, branches cells Nuclei - one or two central nuclei Contractile proteins - striated myofilaments Metabolism - aerobic cellular respiration Intercellular connections - intercalated discs Fibrous skeleton - dense irregular connective tissue |
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Two large arteries attach to the ventricles known as? |
1. Pulmonary trunk 2. Aorta |
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Pulmonary trunk ? |
Transports blood away from the right ventricle to the lungs and divides into pulmonary arteries |
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Aorta is ? |
Transports blood away from the left ventricle to the entire body |
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Large veins that deliver blood to the atria known as? |
1. Superior vena cava 2. Inferior vena cava 3. Pulmonary veins |
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Superior vena cava is ? |
Drains blood from the upper limbs and head into the right atrium |
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Inferior vena cava is? |
Drains blood from the lower limbs and thoracic and abdominal cavities into the right atrium |
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Pulmonary veins ? |
Drains blood from the lungs into the left atrium |
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The great vessels coming together |
- two pulmonary arteries and four pulmonary veins form the pulmonary circuit between the heart and lungs - superior and inferior vena cavae and aorta form the systemic circuit between the heart and body cells - arteries take blood away from the heart and veins drain blood back to the heart |
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Coronary arteries |
First blood vessels that branch off the aorta carry blood to the heart muscle cells in the myocardium |
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Coronary veins |
Vessels that carry blood away from the myocardium |
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Coronary arteries |
Are located in the coronary sulcus and inter-ventricular grooves of the heart and branch into smaller arteries to supply the heart wall via capillaries Right coronary artery branches into the right marginal artery and posterior interventricular artery Left coronary artery branches into the circumflex artery and anterior interventricular artery |
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Coronary veins |
Three main coronary veins the great, middle, small cardiac veins which all drain into the coronary sinus |
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Coronary sinus |
A large vein on the posterior aspect of the coronary sulcus which drains blood into the right atrium |
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The cardiac conduction system has 4 parts |
1. Sinoatrial SA node 2. Atrioventricular AV node 3. Atrioventricular AV bundle 4. Purkinje fibers |
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Sinoatrial node known as SA node aka pacemaker |
- located in the wall of the right atrium inferior to the opening of the superior vena cava - cells initiate cardiac impulses and are responsible for rhythmic contractions of the heart - atria contract due to the impulses from SA node |
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Atrioventricular node known as AV node |
- located in the interatrial septum - provides the normal conduction between the atria and ventricles - impulse is delayed by the small diameters of the junctional fibers and AV node allows time for complete atrial contraction |
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Atrioventricular bundle known as AV bundle |
- located in the upper part of the interventricular septum - divides into a right and left bundle branch to reach each ventricle |
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Purkinje fibers |
Carry impulses from the apex to all parts of the ventricular myocardium and ensuring complete ventricular contraction |
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Control of the cardiac conduction system |
- Heartbeat is controlled by the SA node - HR & strength of contraction are controlled by the autonomic nervous system |
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Cardiac center |
Barorecptors and chemoreceptors send messages to the cardiac Center - cardiac Center is found in a region of the brain called the medulla oblongata |
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Cardiac Center is composed of |
- cardioinhibitory Center - decreases HR (parasympathetic innervation via cranial nerve x) vagus - cardio accelerator Center - increases both HR and force of contraction |
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Two types of action potentials APs occur in the heart? |
1. Within the SA node of the cardiac conduction system - spreads the AP throughout all parts of the myometrium of the heart 2. Action potential reaches the contractile cells of the heart |
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Physiology of AP in the SA node |
- Na+ ions leak into the node between heartbeats causing a rise in the resting membrane -60 mV to -40 mV - once -40 mV occurs, calcium -sodium channels open, leading to rapid entry of Ca2+ and Na+, causing AP - calcium-sodium channels open to allow k+ ions to leave stops AP - hyperpolarization occurs and the resting membrane potential drops to -60 mV - spontaneous depolarization occurs due to constant leaking of Na+ inward |
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AP in contractile cells |
- heartbeat an AP occurs twice, once in the atrial cells and then again in the ventricular cells - resting membrane potential of atrial cells is -80 mV and -90 mV for ventricular cells - threshold for ventricular muscle cells is -75 mV |
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Three steps for ventricular muscle action potential? |
1. Rapid depolarization (fast Na+ channels open at -75 mV) 2. Plateau (from +30 to -60 mV fast Na+ channels close and slow Ca2+ channels open, Ca2+ enters sacroplasm) 3. Repolarization (slow Ca2+ channels close and slow K+ channels open, K+ rushes out, return to -90 mV) |
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Heart muscle contractile cells have two different refractory periods? |
1. Absolute ~200 Msec long 2. Relative ~50 msec long |
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Heart muscle contractile cells have two different refractory periods? |
1. Absolute ~200 Msec long 2. Relative ~50 msec long |
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Role of calcium in cardiac contractions? |
- Ca2+ enters via plasma membrane during plateau (20% needed for contraction) - remaining 80% is released from the sacroplasmic reticulum (reverse) due to the rise in Ca2+ levels in the cardiac muscle cells |
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Cardiac cycle |
One complete heartbeat - atria contract, atria relax, ventricles contract, ventricles relax |
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Cardiac cycle |
One complete heartbeat - atria contract, atria relax, ventricles contract, ventricles relax |
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Systole |
Contraction of a heart chamber |
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Diastole |
Relaxation of a heart chamber |
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5 phases in a cardiac cycle |
1. Atrial systole & ventricular filling - ventricles fill with blood -cuspid valves open, semilunar valves closed 2. Isovolumetric contraction -atria relax, ventricles contract - cuspid and semilunar valves closed 3. Ventricular ejection - ventricles Empty - cuspid valves closed, semilunar valves open 4. Isovolumetric relaxation - atria and ventricles relax - cuspid and semilunar valves closed 5. Atrial diastole & ventricular filling - blood into RA from SVC, IVC & coronary sinus, LA from pulmonary veins and then into ventricles - cuspid valves open, semilunar valves closed |
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Heart sounds first sound lub |
Is due to the closing of the cuspid valves during ventricular systole |
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The second heart sound dub |
Is due to the closing of the semilunar valves during atrial diastole and ventricular diastole |
