Heart (Ch 22) Flashcards
What are the functions of the cardiovascular system?
- Transport system of the body (oxygen, nutrients, waste, carbon dioxide, hormones)
- Distributes heat- maintains body temp
- Keeps pH/osmotic balance
- Prevents blood loss, wound healing, defends against disease
Where is the heart?
in the mediastinum (w/trachea and esophagus) between thorax and lungs
What is the pericardium?
a serous fluid-filled sac surrounding the heart
- anchors, lubricates, and prevents heart from overfilling
- three layers
What are the three layers of the cardiac wall?
- epicardium: outer visceral layer of pericardium, CT
- myocardium: cardiac muscle layer, contracts heart wall
- endocardium: inner lining of heart, simple squamous epithelium + thin CT
What is the function of the right atrium?
receives deoxygenated blood from heart
What is the function of the left atrium?
receives oxygenated blood from the body
What is the function of the right ventricle?
receives deoxygenated from right atrium, pushes it to the lungs (thin wall)
What is the function of the left ventricle?
receives oxygenated blood from the left atrium, pushes it to the body (thick wall - needs more force)
What are the four major vessels of the heart?
- Vena Cava
- Pulmonary Trunk
- Aorta
- Pulmonary Veins
What is the function of the Vena Cava?
–> superior vs. inferior
takes deoxygenated blood from body and pushes it into the right atrium
What is the function of the Pulmonary Trunk?
take deoxygenated blood from the right ventricle and push it to the lungs
What is the function of the Aorta?
take oxygenated blood from left ventricle and send it to the body
What is the function of the (4) Pulmonary Veins?
receive oxygenated blood from lungs and send it to the left atrium
What are the four valves of the heart? What do they do?
- -> ensure one-way flow between heart chambers and great vessels (only open in one direction - snap shut against “back flow”)
1. Tricuspid/Right Atrioventricular - 3 flaps
2. Bicuspid/Left Atrioventricular - 2 flaps
3. Pulmonary/Right Semilunar- between r. vent and pulm trunk
4. Aortic/Left Semilunar- between left vent and aorta
What are the chord tendinae?
“heart strings”
-connect valves to papillary muscle to help prevent valve flaps from opening when ventricles contract
What are the steps of the cardiac cycle?
- Atrial Systole
- Ventricular Systole
- Ventricular Diastyole
Atrial Systole
- atrioventricular valves open
- semilunar valves close
- atria contract
- blood pushed into ventricles
Ventricular Systole
“Lubb”
- AV valves close
- semilunar valves open
- ventricles contract
- blood–>vessels (aorta/pulm arteries)
Ventricular Diastole
“Dubb”
- ALL valves close
- atria refills w/blood
What are the parts of the heart conducting system?
- Sinoatrial Node (SA Node)
- Atrioventricular Node (AV Node)
- Atrioventricular Bundle (Bundle of His)
- Bundle Branches
- Perkinje Fibers
Sinoatrial Node (SA Node)
generates impulse for atrial contraction, “pacemaker,” –> posterior wall of atria below superior vena cava opening
Atrioventricular Node (AV Node)
impulses pause here –> on floor of right atrium, near opening of coronary sinus
Atrioventricular Bundle (Bundle of His)
connect atria + ventricles
Bundle Branches
impulses move down ventricles via these
Perkinje Fibers
throughout myocardium of ventricular walls, contraction of ventricles
What part of heart conducting system acts as the “pacemaker?”
SA Node
