WEEK V (Heart) Flashcards
What does the circulatory system consist of?
- Heart
- Blood vessels
- blood
What is the importance of the circulatory system?
The circulatory system contributes to homeostasis by serving as the body’s transport system
What is the importance of the Heart?
- All body tissues constantly depend on the life-supporting blood flow from the heart
- The heart drives blood through the blood vessels for delivery to the tissues in sufficient amounts
What is Systemic Blood Flow?
Cardiac output from the left side of the heart
What is Pulmonary Blood Flow?
Cardiac output from the right side of the heart
Describe the direction of blood flow
1) From the LUNGS to the LEFT ATRIUM via the PULMONARY VEIN
2) From the LEFT ATRIUM to the LEFT VENTRICLE through the MITRAL VALVE
3) From the LEFT VENTRICLE to the AORTA through the AORTIC VALVE
4) From the AORTA to the SYSTEMIC ARTERIES and the SYSTEMIC TISSUES
5) From the TISSUES to the SYSTEMIC VEINS and VENA CAVA
6) From the VENA CAVA to the RIGHT ATRIUM
7) From the RIGHT ATRIUM to the RIGHT VENTRICLE through the TRICUSPID VALVE
8) From the RIGHT VENTRICLE to the PULMONARY ARTERY through the PULMONIC VALVE
9) From the PULMONARY ARTERY to the LUNGS for oxygenation
What is the Heart?
The pump that imparts pressure to the blood to establish the pressure gradient needed for blood to flow to the tissues
What are the blood vessels?
Passageways through which blood is directed and distributed from the heart to all parts of the body and subsequently returned to the heart
What is blood?
The transport medium within which materials being transported long distances in the body (e.g O2, CO2, Nutrients, Wastes, Electrolytes, Hormones) are dissolved or suspended
What is pressure?
The force exerted on the vessel walls by the blood pumped into them by the heart
What is Resistance?
The opposition to blood flow largely caused by friction between the flowing blood and the vessel wall
Do both sides of the heart simultaneously pump equal amount of blood?
YES
What is the difference between Pulmonary circulation and Systemic circulation?
PULMONARY CIRCULATION is a low-pressure, low-resistance system whereas SYSTEMIC CIRCULATION is a high-pressure, high-resistance system
Why is the heart muscle on the left side thicker than the right side?
Since the left side works harder because it pumps an equal volume of blood at a higher pressure into a higher-resistance and longer system
What are the functions of atrioventricular valves?
- Let blood flow from the atria into the ventricles during VENTRICULAR FILLING
[when atrial pressure exceeds ventricular pressure] - Prevent back flow of blood from the ventricles into the atria during VENTRICULAR EMPTYING
[when ventricular pressure exceeds atrial pressure]
What would happen if the rising ventricular pressure did not force the AV valves to close as the ventricles contracted to empty?
Much of the blood would inefficiently be forced back into the atria and veins instead of being pumped into the arteries
What are the Right and Left Atrioventricular valves called?
- Right AV = Tricuspid Valve (3 cusps)
- Left AV = Bicuspid Valve/Mitral Valve (2 cusps)
What is the function of the Chordae Tendineae?
- Fasten the edges of the AV valve leaflets
- Tough, thin cords of tendinous-type tissue
- Prevent the valve from EVERTING
What do Chordae Tendineae attach to?
Papillary muscles
What happens when the ventricles contract?
Papillary muscles also contract -> Pulls downward on the CHORDAE TENDINEAE -> Pulling exerts tension on the closed AV valve cusps to hold them in position -> Action helps keep the valve tightly sealed in the face of a STRONG BACKWARD PRESSURE GRADIENT
Describe the structure of the layers of the heart
- Heart walls composed primarily of spirally arranged cardiac muscle fibers
- Outermost layer of heart is VISCERAL LAYER of SEROUS PERICARDIUM which surrounds the HEART & ROOTS of the CORONARY VESSELS
What are the layers of the heart? (outer to inner)
- FIBROUS PERICARDIUM
- PARIETAL LAYER OF SEROUS PERICARDIUM
- PERICARDIAL CAVITY
- EPICARDIUM
- MYOCARDIUM
- ENDOCARDIUM
What is the function of the Serous Pericardium?
- Protects the heart
- Provides signals for embryonic heart formation and maturation
- Secretes factors for CARDIOMYOCYTE PROLIFERATION & SURVIVAL
- Helps with the Heart’s INJURY RESPONSE & REGENERATION
Describe the Cardiac muscle
- Sarcomeres are connected end-to-end to form MYOFIBRILS
- Many of these Myofibrils can be found in the SARCOPLASM of the CARDIAC CELL
- Contains SARCOLEMMA with deep invaginations called T-TUBULES that are responsible for bringing the action potential to the SARCOPLASMIC RETICULUM