Week 1 Flashcards
What are the basic functions of the cardiovascular system?
- transport essential substances to tissues
- remove by-products of metabolism
- regulation of body temperature
- humoral communication throughout body
- adjustments of oxygen and nutrient supply in different physiologic states
Basic components of the circulatory system
- pump: has an electrical system for regular running
- series of distributing and collecting tubes
- extensive system of this vessels that permit rapid exchange between the tissues an the vascular channels
Basic description of heart
- 2 pumps
- RV: pulmonary circulation
- LV: systemic circulation
-valves cause unidirectional flow in the heart
ant parts of the heard cause unidirectional flow in the cardiovascular system?
-valves
what part of the circulation distributes blood to the tissues?
Arteries and arterioles are responsible for distribution
What part of the circulation contains the majority of total blood volume?
The venous system (venules, veins, and vena cava contain 70% of the blood volume
The greatest resistance in blood flow occurs in what part of the circulation?
Vascular resistance is greatest in the arterioles
What is the function of the capillaries?
This is where exchange takes place of diffusion substances
Is blood flow is pulsatile or non-pulsatile in the capillaries?
Non-pulsatile
As the cross-sectional area of a vascular bed increases, the velocity of blood flow increases or decreases?
Decreases
Velocity of blood flow in inversely related to the cross-sectional area of the vascular system
What contributes to optimal conditions of capillary function?
- blood velocity is slow in capillaries
- vessels are thin to permit rapid exchange between the tissue and the vascular channels
What is the control of blood flow related to in the majority of the tissue beds of the body?
It is almost always controlled in relation to the tissue needs.
Describe the boundaries of the mediastinum
-it contains the heart and its vessels, portion of the esophagus, trachea,
- anteriorly: sternum to vertebral column
- laterally: mediastinal pleura
- superiors: thoracic inlet
- inferiorly: diaphragm
In what part of the mediastinum is the heart located?
Middle portion of inferior mediastinum
Name the different layers of the pericardium
- Fibrous
- Serous
- parietal layer: outer layer
- visceral layer: inner wall, in contact with heart
What nerve travels across the pericardium to the diaphragm?
From which nerve roots do these nerves originate?
The phrenic nerve
Phrenic nerve originates in C3-C5
What is the sympathetic innervation of the heart?
- T1-T4
- stellate ganglia and middle cervical ganglia
- innervation of SA and AV nodes and ventricles
If sympathetic output is increased, both HR and contractility will increase
What is the parasympathetic innervation to the heart?
- originates in medulla oblong at a
- Vagus nerves
- much innervation to SA and AV nodes (and atrial tissue)
- little innervation to ventricles
Stimulation will slow HR and decrease contractility; at maximum only decrease by about 30%
What are the different parts of the condition system?
- sinoatrial node (SA)
- interatrial conduction pathways (SA to LA)
- internode conduction pathways (SA to AV)
- atrioventricular node
- bundle of HIS
- Bundle branches
- left bundle branch
- left anterior division
- left posterior division - right bundle branch
- left bundle branch
What structures are part of the right atrium?
- Vena cavae
- superior
- inferior
- eustachian valve: part of fetal circulation
- Crista terminalis: divides right atrium
- right atrial appendage (right auricle)
- Coronary sinus (venous drainage of heart)
- Fossa ovalis
- Tricuspid valve
What is the coronary sinus?
What does it drain into?
- collection of veins joined together to form a large vessel that collects blood from the heart (myocardium)
- drains into the right atrium
Describe the tricuspid valve apparatus.
How many leaflets does the valve have?
-separates the right atrium from right ventricle
- 3 leaflets
- anterior leaflet
- posterior leaflet
- septal leaflet
Describe the thickness of the walls of the RV in comparison to those of the LV
The walls of the LV are thicker than the RV
Describe the shape of the right ventricle in cross-section
Crescent- shaped
What portion of the ventricle is common to both the RV and LV?
Septum
Describe the shape of the left ventricle in cross-section
Circular
How many pulmonary veins are normally present?
What cardiac chamber do they drain into?
There are 4 pulmonary veins: 2 from right lung, and 2 from left lung. They all drain into the left atrium
Is pulmonary vein blood oxygenated or non-oxygenated?
Oxygenated
In what left atrial structure may blood clots (thrombi) develop in the setting of atrial fibrillation?
They tend to form in the left atrial appendage
What is the function of the papillary muscle?
-they attach to the atrioventricular valves via chordate tendineae and contract to prevent inversion or prolapse of the valves on systole.
What cardiac valves are associated with papillary muscles?
Mitral and tricuspid
How many leaflets are found in a normal aortic valve?
3 - trileaflet
Where are the origins of the coronary arteries in relationship to the aortic valve?
- Right and left main coronary arteries originate from Sinuses of Valsalva.
- occurs just above the aortic valve
How many leaflets are found in the mitral valve?
- 2 leaflets
- anterior leaflet: wide and short
- posterior leaflet: narrow and long
How many leaflets are found in the pulmonic valve?
3 cusps
- anterior
- right
- left
What is the ramus intermedius?
A variant coronary artery resulting from the trifurcation of the left main coronary artery.
What are the major branches of the coronary arteries?
- Right coronary
- Dominance: in 85% of individual the RCA supplies the posterior descending artery (PDA)
- Left coronary
- Left main bifurcates to form:
- Left anterior descending (LAD)
- diagonal branches
- Left circumflex
- obtuse marginal(es)
- Ramus intermedius (37%)
- the additional branch in people who have a tri-frucation of the left main
- Left anterior descending (LAD)
- Left main bifurcates to form:
What determines dominance in regards to the coronary arteries?
The artery that supplies the posterior third of the interventriuclar septum - the posterior descending artery (PDA) determines the coronary dominance. If the posterior descending artery is supplied by the right coronary artery (RCA), then the coronary circulation can be classified as right-dominant
what are the pressures of the 4 chambers of the heart?
- right atrium: 0-5. (6-8 common reference)
- right ventricle: 20-30
- left atrium: 6-12
- left ventricle: 100-140
- right ventricle is a low-pressure pump
- left ventricle is a high-pressure pump
