Cardiovascular Flashcards
Not completed! Goes up until the topic of the Pressure-volume curve
What is Ohm’s law related to hemodynamics?
- F = ∆P/R
F = flow
∆P = pressure difference between two fixed places
R = resistance to flow
To have blood flow, what must occur?
Pressure must being greater than resistance
Define
Hydrostatic pressure
Pressure exterted by a fluid
What happens when there in no pressure difference?
There is no flow
Where does blood pressure from?
Contraction of heart chambers and pressure of blood on the walls of the blood vessels and heart chambers
What determines resistance to blood flow?
- Viscosity: friction between molecules of a flowing fluid
- Length and diamter of blood vessel: determines the amount of contact between moving blood and stationary wall of vessel
What is poiseuille’s equation?
Equation to determining resistance
Define
Laminar flow
Flow characterized by fluid particles following smooth paths in layers, with each layer moving smoothly past the adjacent layers with little or no mixing.
What are the functions of the cardiovascular system? (5)
- To deliver oxygen and nutrients
- Removed waste products of metabolism
- Fast chemical signalling to cells by circulating hormones or neurotransmitters
- Thermoregulation
- Mediation of inflammatory and host defense responses against invading microorganisms
What are the main components of the cardiovascular system? (3)
- Heart (Pump)
- Blood vessels (Pipes)
- Blood (the fluid to be moved)
What are the vessels in the cardiovascular system? (5)
- Arteries
- Arterioles
- Capillaries
- Venules
- Veins
What are arterioles?
Small branching vessels with high resistance; branches off from arteries
What are arteries?
Larger vessels which move away from the heart; typically carry oxygenated blood
What are veins?
Larger vessels that carry blood towards the heart
What are capillaries?
Small vessels that transport bood between small arteries and venules; where the exchange of materials occurs
What are venules?
Small branching vessels (capillaries to veins) with low resistance
What is the benefit of a closed circulatory system?
It generates greater pressure
What are the four chambers of the heart?
- Right atria
- Right ventricle
- Left atria
- Left ventricle
Describe atria
- Thin-walled
- Low pressure chambers
- Receives blood returning to the heart
Describe ventricles
- Thick-walled
- Involved in forward propulsion of blood
- Receives blood from the atrias, to bring back to the body
What divides the heart?
Septa
What is the interartial spetum?
The septum that separates the left and right atria
What is the interventricular septum?
The septum that separates the left and right ventricles
How does the heart work as a dual pump?
- First pump: carries oxygen-poor blood to the lungs, and then delivers oxygen-rich blood back to the heart
- Second pump: delivers oxygen-rich blood to the body
What is pulmonary circulation?
- Blood to and from the gas exchange surfaces of the lungs
- Blood entering lungs = poorly oxygenated blood
- Oxygen diffuses from lung tissue to blood
- Blood leaving lungs = oxygenated blood
What is systemic circulation?
- Blood to and from the rest of the body
- Oxygen diffuses from blood to body tissues
- Blood entering tissues = oxygenated blood
- Blood leaving tissues = poorly oxygenated
What is the path of blood flow in the left heart?
Receives blood from pulmonary circulation and pumps to systemic circulation
What is the path of blood flow in the right heart?
Receives blood from systemic circulation and pumps to pulmonary circulation
What is the path for pulmonary circulation?
- Pulmonary trunk
- Pulmonary arteries
- Pulmonary arterioles
- Capillaries of lungs
- Pulmonary venules
- Pulmonary veins
- Enters left heart
What is the path of blood flow in systemic circulation?
- Aorta
- Arteries
- Arterioles
- Cappillaries
- Venules
- Veins
- Venae cavae
- Enters the right heart
Where does series flow occur in the cardiovascular system?
At the heart level; blood must pass through the pulmonary and systemic circuits in sequence
Where does parallel flow occur in the cardiovascular system?
At the organ level; each organ is supplied by a different artery and flow is independently regulated
How does the distribution of blood flow change during exercise?
The skeletal muscles get a higher flow than abdonimal organs; this is compared to the flow distribution at rest
When does the distribution of blood flow differ?
- Rest
- Exercise
- Emergency situations
What is the pericardium?
Fibrous sac surrounding the heart and roots of great vessels
What are the functions of the pericardium? (4)
- Stabilization of the heart in the thoracic cavity
- Protection of the heart from mechanical trauma/infection
- Secretes pericardial fluid to reduce friction
- Limits overfilling of the chambers, preventing sudden distension
What are the three layers of the pericardium?
- Fibrous pericardium
- Partietal pericardium
- Visceral (epicardium)
What reduces friction within the pericardial cavity?
Pericardial fluid
What is pericarditis?
Inflammation of pericardium
What is a cardiac tamponade?
Compression of heart chambers due to excessive accumulation of pericardial fluid; this causes decreases in ventricular filling
Which ventricle has a thicker wall? higher pressure?
The left ventricle has a thicker wall, which means it develops higher pressure
What is epicardium?
The visceral pericardium; it covers the outer surface of the heart
What is the myocardium?
The muscular wall of the heart; contains the cardiac muscle cells, blood vessels, and nerves
What is the endocardium?
The endothelium covering inner surfaces of the heart and heart valves
What are myocytes?
- Cardiac muscle cells
- Branched (“Y”) and joined longitudially
- Striated
- One nucleus
- Many mitochondria
What are intercalated disks?
- Interlocking region of attachment
- Include desmosomes and gap junctions
What are desmosomes?
- Structures that anchor cells together in tissues subject to considerable stretching
- Mechanically couples cells
What are gap junctions?
- Communicating junctions
- Transmembrane channels that link adjacent cells
- Electrically couple cells
- Allows movement of APs, and molecules/ions