Cardio System(A&P) Flashcards
Heart
- slightly larger than an adults fist
- located in thoracic cavity within the mediastinum
- shaped like a cone:
base: superior margin to which the great vessels are attached
apex: pointed left and down - point of maximal impact is at the level of the 5th intercostal space, midclavicular on the left side
Pericardium(covering)
- covering the heart
- fibrous pericardium
- serous pericardium
1. parietal layer
2. serous fluid(pericardial fluid)
3. Viceral layer(epicardium)(heart wall)
Endocardium(inner layer of heart wall)
- visceral layer of the serous pericardium
- squamous epithelieum cells and connective tissue
- rough surface promotes blood clotting
Myocardium(middle layer of heart wall)
- compose of cardiac muscle
- responsible for pumping blood
- made up of cardiac muscle cells
- striated slightly
- mononuclieated
- connected two each other by intercalted disc
- involuntary control
- sets its own rhythmn
Epicardium(outer layer of heart wall)
-contains visceral layer of the serous pericardium
Partition of the Heart(Septum)
- heart is a pump, double pump
- divided into two separate pumps by the septum(myocardium)
- right side=recieves and pump deoxygenated blood
- left side=recieves and pumps oxygenated blood
Atria(chamber of the heart)
- recieve blood
- atria upper chamber
- recieve blood entering the heart and pumping into ventricles
- atria had thin walls
Right atrium
- recieve blood returning from the body(deoxygenated)
- two major blood vessels return blood to the atrium superior and inferior vena cava
Left atrium
- recieves blood returning from the lungs(oxygenated)
- blood return from lungs to heart by 4 pulmonary veins
Ventricles(pump blood)
- two lower chambers
- pump blood out of the heart
- they have thick walls
Right Ventricles
- receives blood from the right atrium
- pumps into the pulmonary trunk
- which divides into right and left pulmonary artery
Left Ventricles
- thicker walls thank right ventricles
- recieve blood from left atrium
- and pump itout into the aorta
Valves of the Heart
- heart valves provide for one way blood flow
- Right AV valve
- Left AV valve
- Aortic SL valve
- Pulmonary Sl valve
Right Atrioventricular Valve: Tricuspid Valve
- open when right atrium contracts
- close when right ventricle contracts
Pulmonic Valve: Semilunar Valve
- located btw right ventricle and pulmonary trunk
- opens when right venticle contracts
- closes when right ventricle relaxes
Left Atrioventricular Valve: Bicuspud: Mitral Valve
- open when left atrium contracts
- close when left ventricle contracts
Aortic valve: Semilunar valve
- located btw left ventricle and aortic
- open when left ventricle contracts
- close when left ventricle relax
Cardiac Cycle
- sequence of events in one heart beat
- blood is constantle flowing in from the veins into the atria
- atrial systole followed by ventricular systole
Cardiac Cycle
1-the atria are relaxed and fill with blood(blood flows passively into the ventricles)=atrial dystole
2-atrial contraction pumps the remainging blood into the ventricles=atrial systole
3-ventricle contraction(the atria are relaxed) pumps blood into the arteries(the AV valves close and the SL valves open)=ventricular systole
4-ventricular relaxation-ventricles are filling up with blood(SL valves close and the AV valves open)=ventricular dystole
Cardiac output
- amount of blood pumped by each ventricle in one minute
- stoke volume x hour
- 5-6L/min
- varies to meet the body demand for 02
Factors that affect cardiac output
1) Stroke volume: volume of blood pumped by each ventricle w/ each heartbeat(cardiac cycle)
2) preload: amount of blood in the ventricle at the end of diasytole
3) Afterload:pressure(resistance) ventricle overcomes to eject blood into the artery(vascular resistance)
4) contractility: strength of contraction of the myocardium
Conduction system of the Heart
1) SA Node
2) AV Node
3) BOH
4) R/L bundle branches
5) Purkinjie Fibers
SA Node: Sinoatrial Node
- specialized mass of tissue that initates the signal for each heart beat
- located in the upper wall of the right atrium
- sets the normal rate of heart contractions(normal sinus rythmn) 60-100
- called the pacemake of the heart
AV node: Atrioventricular Node
- located at the top of the intraventricular septum
- recieves the signal from the SA nose and delays conducting it usually until the end of the atrial systole
- transmits the signal to the BOH
- can initate the signal for heart beats if the SA node is damaged but at a lower rate(40-60)