Unit 1 Lecture Flashcards
What are the three components of the cardiovascular system?
- The heart: which acts as a pump to propel….
- Blood: which moves through tubes called….
- Blood vessels: which conduct blood throughout the body
What does the circulation of blood look like in the heart?
Circulation is continuous with two trips through heart before returning to where you started. The heart is thus often called a double pump.
What is the heart often called?
A double pump
What is each stop at the heart?
Each stop at the heart is the end of a separate circuit
(Heart -> arteries -> capillaries -> veins -> heart)
What are the two cardiovascular circuits?
What does each side of the heart contain?
It contains an atrium and a ventricle. Blood enters into the heart at an atrium and is ejected out of the heart from a ventricle.
Discuss systemic circuit
- Carries oxygenated blood (“arterial blood:) to body cells/tissues/organs
- Begins with the left ventricle of the heart (ejects blood into the aorta) and ends with the right atrium (collects returning blood)
- Distributes blood in a parallel manner. Major recipients of blood include: kidneys, GI system, skeletal muscle, brain, skin, liver, bone, and heart
Discuss the pulmonary circuit (Pulmonary Circulation)
- Carries de-oxygenated blood (“venous blood”) to the lungs where it is reloaded with oxygen (and emptied of excess carbon dioxide) before returning to the heart
- Begins with the right ventricle of the heart (ejects blood into the pulmonary trunk) and ends with the left atrium (collects the returning blood)
- Requires proper functioning of the respiratory system
What does blood flow with?
Blood flows with a concentration gradient
-Blood has more pressure at the start where it is pushed out
Study the circulation of blood
What is cardiac output?
It is the amount of blood pumped by a ventricle per unit time (measured in L/min)
Does the systemic or pulmonary circuit have a faster cardiac output?
Both systemic and pulmonary circuits have the same cardiac output. (Left and right ventricles eject the same amount of blood)
-It is equal to about 5 L/min under resting conditions
Does cardiac output change?
Cardiac output changes to meet the needs of the body. CO can be increased as much as 30 L/min during maximal exercise
What is a heart and what is it composed of?
- Is composed primarily of cardiac muscle
- Is a double pump
- Contains 4 chambers
- Directs blood flow by means of 4 valves
- Is suppled with blood by the first two arteries formed off of the aorta
What are the four chambers of the mammmalian heart? And how does blood move through them?
- Right atrium (RA)
- Left atrium (LA)
- Right ventricle (RV)
- Left ventricle (LV)
What do the atria and ventricles do?
The atria recieves blood; the ventricles force blood out of the heart into systemic and pulmonary circuits
Which ventricle has more muscle and why?
Due to the difference in workload, the left ventricle has much more muscle (is much thicker) than the right ventricle.
Why does blood happen to move only in one direction (always into atria, then ventricles, and then out of the heart)?
Heart valves
Discuss heart valves
- There are four “one-way” heart valves
- Heart valves ensure that blood flows through the heart in only one direction
- There are two between the atria and ventricles (left and right atrioventricular valves)
- There are teo semilunar valves (one between LV and aorta, and the other between RV and pulmonary trunk)
What is the left Atrioventricular Valve called and what does it separate?
The left AV is also called the bicuspid valve (“two cusps”) or mitral valve
-It separates the left atrium and left ventricle
What is the right Atrioventricular Valve called and what does it separate?
The right AV is also called the tricuspid valve (“three cusps”)
-Separates the right atrium and right ventricle
What are chordae tendinae, what do they do, what do they prevent?
- The tissue flaps of the AV have tendons known as chordae tendinae
- Chordea tendinae attach the valve cusps to the inner ventricular walls
- Chordae tendinae prevent “prolapse” of the valves into the atria during ventricular contraction
What do papillary muscles do?
Specialized muscles, known as papillary muscles, regulate tension in the chordae tendinae and contract simultaneously with the ventircles
What does the aoritc semilunar valve do?
The aortic semilunar valve separates the left ventricular chamber from the aorta
What does the pulmonary semilunar valve do?
The pulmonary semilunary valve separates the right ventricular chamber from the pulmonary trunk
How do the aortic semilunar valve and pulmonary semilunar valve open and close?
These valves open in a pressure-dependent manner, meaning that they open and close in response to pressure differences between the major vessels and heart ventricles
Commonality between AV and Semilunar valves?
AV valves open and close together and same with semilunar valves
Summarize CV circulation
Summary of the internal anatomical features of the heart
What is coronary circulation?
Coronary circulation is the part of systemic circulation that provides itself with blood. Collateral routes (anastomoses) ensure blood delivery to heart tissue even if major vessels are occulded. The tissues of the heart are supplied wiht blood from the right and lefr coronary arteries
Where do right and left coronary arteries originate?
Right and left coronary arteries originate on the ascending aorta
Discuss the right coronary artery
Discuss the left coronary artery
Regarding coronary circulation, what does the great cardiac vein do?
The great cardiac vein drains the anterior heart
Regarding coronary circulation, what does the middle cardiac vein do?
The middle cardiac vein drains the posterior heart
Regarding coronary circulation, what does the coronary sinus do?
Borth middle and great cardiac veins drain into the coronary sinu which in turn drains into the right atrium
What are the two types of congestive heart failure?
- Diastolic: heart cant fill
- Systolic: heart cant pump
What is congestive heart failure caused by?
- Cardiovascular disease
- Hypertension
What does cardiac muscle consist of?
Cardiac muscle consists of branched, striated fibrt with one or two centrally located nuclei
What are actin and myosin?
Actin and myosin are packaged in myofibrils, in the same arrangement as thet are in skeletal muscles; its sarcmeres
Why do the cardiac muscles contain a branching pattern?
Branching pattern, which forms a network that can facilitate the transmission of electrical impuses in all directiosn
What are gap junctions?
- Gap junctions are small channels which allow electrical impulses to pass quickly from one cell to the next
- Gap junctions are located in “intercalated discs” which lie between adjacent mucle fibers
- Intercalated discs also contain desmosomes, which hold adjacent cells toegther
