2 - APP - Unit 5.2 - Cardiovascular System Flashcards
Cardiovascular System
Heart + blood vessels + blood
Cells exchange materials with immediate environment (insterstitial fluid).
To maintain homeostasis, environment must be renewed
As blood flowing through body tissue:
- movement of nutrients & oxygen from blood to cells
- opposite movement of wastes, carbon dioxide & heat from cells into bloodstream
Heart anatomy - Heart
Hollwo, muscular, double pump circulating blood through blood vessel to all body parts
Heart anatomy - Paricardium
Double layer of fibrous tissue surrounding the heart
Heart anatomy - Paricardial fluid
Lubricating fluid filling the space between the two pericardial layers
Prevents the two layers from rubbing against each other & creating friction
Heart anatomy - Myocardium
Cardiac muscle tissue
Major portion offre heart
Heart anatomy - Endocardium
Smooth tissue on the inner lining
Covers heart valves & lines blood vessels providing smooth transit for flowing blood
Heart anatomy - Heart division
Heart separated into right & left halves by the interventricular septum
Each half is divided in two parts, creating 4 chambers
Heart anatomy - Heart division - Atrium
Plural: Atria
= auricles
2 upper chambers
- Right atrium
- Left atrium
They receive & collect blood for both body & lungs
Heart anatomy - Heart division - Ventricles
2 lower chambers
- Right ventricule
- Left ventricle
Pump blood out of the heart into the 2 different circulatory pathways
Heart anatomy - Valves
4 valves:
- 2 atrioventricular valves - between atria & ventricules
- 2 semilunar valves - where blood leaves the heart
Permit blood flow in only one direction
Heart anatomy - Valves - Atrioventricular - Tricuspid valve
Atrioventricular valve
Between right atrium and right ventricle
Tricuspid = 3 points (cusps) of attachement
Heart anatomy - Valves - Atrioventricular - Chordae tendinae
Small fibrous strands connecting the edges of the tricuspid to the papillary muscle that are projections of the myocardium
Heart anatomy - Ventricules & Valves - Right side process
When right ventricule contracts, the papillary muscle contracts pulling on the chordae tendinae to prevent inversion of the tricuspid valve.
Blood flows from right atrium into right ventricle. Not opposite direction.
Heart anatomy - Valves - Atrioventricular - Bicuspid valve
= Mitral valve (resembles a miter = a bishop’s hat)
Atrioventricular valve
Between left atrium and left ventricle
Blood flows from left atrium into left ventricle. Not opposite direction
Heart anatomy - Valves - Semilunar valves
- Pulmonary semilunar valve
- Aortic semilunar valve
Heart anatomy - Valves - Semilunar - Pulmonary semilunar valve
At the orifice (opening) of the pulmonary artery
Allows blood to travel from right ventricle into pulmonary artery and then into the lungs
Heart anatomy - Valves - Semilunar - Aortic semilunar valve
At the orifice of the aorta
Allows blood to pass from left ventricle into aorta, but not backward into left ventricule
Heart anatomy - Structures leading to & from the heart
- Superior vena cava & inferior vena cava
- Coronary sinus
- Pulmonary arteries
- Aorta
- Pulmonary veins
Heart anatomy - Structures leading to & from the heart - Superior vena cava & inferior vena cava
Large venous blood vessels bringing deoxygenated blood (has lesser amount of oxygen) to the right atrium from the entire body
Heart anatomy - Structures leading to & from the heart - Coronary sinus
Transports blood from heart muscle tissue itself to right atrium
Heart anatomy - Structures leading to & from the heart - Pulmonary arteries
Transports blood away from right ventricle to the lungs for oxygenation
Heart anatomy - Structures leading to & from the heart - Aorta
Transports blood away from left ventricule to the rest of the body
Heart anatomy - Structures leading to & from the heart - Pulmonary veins
Transports blood from the lungs to left atrium
Heart physiology
Works as a double pump
Two major functions:
- Right heart
- Left heart
Heart physiology - Right heart
- Deoxygenated blood from body enters right atrium from superior & inferior vena cava
- Then flows through tricuspid valve into right ventricule
- Right ventricule contracts, forcing blood past the pulmonary semilunar valves into the pulmonary arteries, carrying blood to the lungs for oxygenation
Heart physiology - Left heart
- Oxygenated blood from the lungs enters left atrium from pulmonary veins
- Then flows through bicuspid (mitral) valve into left ventricule
- Left ventricule contracts, forcing blood past the aortic semilunar valves into aorta, carrying blood to the rest of the body
Heart physiology - Heart beat
Individual at rest: between 72 to 80 times/minute
Each beat: 60-80 ml of blood ejected from the ventricles (=stroke volume)
Heart physiology - Heart beat - Stroke volume
Quantity of blood ejected from the ventricules at each beat (60-80ml)
Heart physiology - Heart beat - Cardiac output
Total volume of blood ejected from the heart per minute
Adult body average: 5,000ml
So all blood is pumped through the heart about once every minute
Heart physiology - Coronary artery
Heart receives blood from coronary artery
Branches into right and left coronaries arteries, which branch into various coronary arteries feeding heart muscle
Heart physiology - Heart sound - Lubb dubb sounds
Sound made by valves when they close
Heart physiology - Heart sound - Lubb dubb sounds - Lubb sound
Heard first
Closure of Atrioventricular valves (tricuspid & bicuspid)
Heart physiology - Heart sound - Lubb dubb sounds - Dubb sound
= S2 sound
Heard second
Shorter and higher pitched
Closure of Semilunar valves (aortic & pulmonic)
Certain conditions cause changes in action of heart valves.
Control of Heart Contractions
Heart removed from body continues to beat rhythmically
Heartbeat generates in the heart muscle itself
Heart rate: affected by endocrine & nervous systems
Myocardium contracts rhythmically as a forceful pump
Control of Heart Contractions - Sinoatrial (SA) node
= Pacemaker
Group of contracting cells
Control heart muscle contractions
Location: at the opening of the superior vena cava into the right atrium
Sends out electrical impulse that begins and regulate heart
Impulse spreads out over: atria making them contract causing blood to flow downward from the 2 upper atrial chambers through ventricular openings
Impulse eventually reaches Atrioventricular (AV) node
Control of Heart Contractions - Atrioventricular (AV) node
Conducting group of cells between atria & ventricle
From the AV node, the electrical impulse is carries to conducting fibers in the atrioventricular septum (=atrioventricular bundle)
Control of Heart Contractions - Atrioventricular bundle
= Bundle of His
Conducting fibers in atrioventricular septum
Divides into right & left branch, subdividing into fine network of branches spreading throughout the ventricules (=Purkinje network)
Control of Heart Contractions - Purkinje network
Fine network of branches spreading throughout the ventricules (result of division of Atrioventricular bundle)
Electrical impulse shoots along Purkinje fibers to the ventricles causing them to contract.
Heart then rests briefly.
Circulation of Blood
Blood vessels circulate blood through 2 major circulatory systems:
- Cardiopulmonary circulation
- Systemic circulation
Circulation of Blood - Cardiopulmonary circulation
Blood flows from right side of the heart to the lungs and back to left side of the heart
Circulation of Blood - Systemic circulation
Blood flows from left side of the heart to the tissues and cells of the body and back to right side of the heart