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)
Bundle of HIS
- bundle of conducting fibers that travels through the top part of the intraventricular septum
- AV bundle seperate into the R/L Bundle
- The Right bundle goes to the right ventricle
- the left bundle goes to the left ventricle
Purkinjie Fibers
-transmits electrical signal to the ventricular myocardial
Pathway of conduction
1)SA node fires(generates impulse)(starts heart beat)
2A)impulse travels to the atrial myocardial and atrial contract
2B)impulse travels to the AV node
3)at the end of the atrial contraction the AV node transmits the signal to the BOH
4)impulse travel through the BOH to the right and left bundle branches to the purkinjie fibers to the ventricle myocardium and the ventricle contract
Stimulation of the Heart
- medulla oblongata had two cardiac center
- accelerator center provides sympathetic stimulation
- inhibtory center provides parasympathetic stimulation via the vagus nerve(or nerve x)
Bradycardia
-slow, below 60
Tachycardia
-fast. above 100
Blood vessels
- 3 layers
- outer-connective tissue
- middle layer-smooth muscle
- inner-simple squamouse epitheliuem-smooth surface for blood flow
Arteries
- carry blood away from the heart
- thick layer of smooth muscle in the wall
Arterioles
-artery w/ small diameter
Capillaries
- exchage vessels
- have extremely thin walls
- allow diffusion of 02 and nutrients into tissue
- diffusion of waste product from tissue to bloodstream
Venules
smaller in diameter to veins
Veins
thick layer of connective tissue
-think layer of small muscler
have semilunar vavles to prevent backflow
-skeletal muscle pump prevent backflow
-resp pump when inhale chest expand, exhale relax