Cardiovascular and Circulatory System Pt.1 Flashcards
The cardiovascular system includes?
- Heart (pump)
- Blood (fluid)
- Blood vessels including capillaries (tubes)
What does the cardiovascular system transport?
Materials throughout the body
What does the cardiovascular system transport from the external environment?
- Nutrients
- Water
- Gases
What materials does the cardiovascular system transport between cells?
- Hormones
- Immune cells
- Antibodies
What waste eliminated by cells does the cardiovascular system transport?
- Heat
- Metabolic waste
The heart has _________ chambers
Four
Thin-walled upper chambers are called?
Paired atria
Thick-walled lower chambers are called?
Paired ventricles
The heart is mostly made of _________
Myocardium (cardiac muscle)
What is the heart encased in?
Pericardium (connective tissue)
The two major blood circuits are
- Pulmonary circulation
- Systemic circulation
Pulmonary circulation is
Blood flow between the heart and lungs to oxygenate blood
Systemic circulation provides
Blood flow between the heart and the rest of body to deliver oxygenated blood
What is the difference between arteries and veins?
Arteries carry blood AWAY from the heart, whereas veins RETURN blood to the heart
In systemic circulation do arteries carry oxygenated or deoxygenated blood?
Oxygenated
In pulmonary circulation do arteries carry oxygenated or deoxygenated blood?
Deoxygenated
What is the 3rd circuit and what does it do?
Coronary circulation,supplies the surface of the heart
Coronary arteries supply ________________
Oxygenated blood and originate from the base of the aorta
Coronary veins ____________
Largely drain into the coronary sinus, which empties into the right atrium
Myocardial infarction (heart attack) is caused by?
Reduced myocardial blood flow from coronary artery blockage, that can damage the heart muscle
Blood flows sequentially through?
1.Venar cavae (from body circulation)
2. Right atrium
3. Right ventricle
4. Pulmonary artery (to pulmonary circulation)
5. Pulmonary veins (from pulmonary circulation)
6. Left atrium
7. Left ventricle
8. Aorta (to body circulation)
What happens when atria contract?
Move blood into ventricles
What happens when ventricles contract?
Move blood out of the heart
What do heart valves ensure?
One way flow in the heart
Atrioventricular valves are between ________ and the right valve is _________ and the left valve is ______
-Between atria and ventricles
-Tricuspid valve separates RIGHT atrium and ventricle
-Bicuspid (mitral) valve separates LEFT atrium and ventricle
Semilunar valves are between ________ and the right valve is _________ and the left valve is ______
-Between ventricles and arteries
-Pulmonary valve separates RIGHT ventricle and pulmonary trunk
-Aortic valve separates LEFT ventricle and aorta
What are most of the cells of the heart?
Myocardium cells (cardiac muscle cells)
What are myocardium cells?
Striated fibers organized into sarcomeres
What are 1% of myocardium cells ?
Autorhytmic (pacemaker) cells, that generate action potentials
Autorhythmic (pacemaker) cells have ______
- No orgainzed saromeres
- Smaller with few contractile fibers
- Do not contribute to contractile force of heart
What are myocardium cells joined by?
A complex network joined by intercalated discs (cell junctions)
What are the two major components of intercalated discs
- Desmosomes
- Gap junctions
What are desmosomes?
Strong connections that tie adjacent cells together
What do gap junctions do?
Electrically connect cardiac cells
Compared to skeletal muscle cells, myocardium cells____?
- Smaller with single nucleus per fiber
- Branched and join neighboring cells through intercalated disks
- Have gap junctions
- Have more mitochondria (occupy 1/3 of cell volume)
Cardiac muscle has __________ similar to skeletal muscle
Excitation-contraction (EC) coupling
What triggers excitation _________
Action potential
Excitation is triggered by an action potential. Which _____________ and Spreads ____________
-Spontaneously originated in hearts pacemaker cells
-Spreads into contractile cells via gap junctions
Myocardium EC coupling involves ___________
Ca2+ induced Ca2+ release (CICR)
Excitation coupling in Myocardium cells
- Voltage-gated Ca2+ channels in the cell membrane open
- Ryanodine (RYR) open in the sarcoplasmic reticulum (SR) in response to inflow of Ca2+, releasing more Ca2+
-Ca2+ spark summed sparks in a cell lead to contraction - Intracellular Ca2+ binds troponin, leading to contraction by a similar mechanism to skeletal muscle
Myocardium force generated is determined by_____
- Number of active cross-bridges (depends on how much calcium is bound to troponin)
- Sarcomere length (depends on how much blood is in the heart chamber)
Longer action potential prevents ________
Tetanus muscle must relax between contractions to fill with blood
Phases are due to changes in ____________
Voltage-gated ion channels
In cardiac muscle, the refractory period is almost as long as the twitch, preventing __________
Summation/ tetanus
Myocardial autorhythmic cells can spontaneously generate _________
Action potentials via ion movement through channels
Initial depolarization to threshold is due to (autorhythmic cells)
Ca2+ inflow
Rapid depolarization is due to (autorhythmic cells)
Ca2+ inflow
Repolarization is due to (autorhythmic cells)
K+ outflow
