Session 7 - Cardovascular And Lymphatic System Flashcards
What are the two blood circulations?
- Pulmonary circulation
- Systemic circulation
Explain the pulmonary circulation
The right ventricle propels low-oxygen blood returning from the systemic circulation into the lungs via the pulmonary arteries. Carbon dioxide is exchanged for oxygen in the capillaries of the lungs, and then the oxygen-rich blood is returned via the pulmonary veins to the heart’s left atrium.
Explain the systemic circulation
The left ventricle propels the oxygen-rich blood returned to the heart from the pulmonary circulation through systemic arteries, i.e. the aorta and its branches, exchanging oxygen and nutrients for carbon dioxide in the remainder of the bodies capillaries. Low-oxygen blood returns to the heart’s right atrium via systemic veins, i.e. tributaries of the superior and inferior vena cava
Name the two parallel muscular pumps of the heart.
- Systemic pump
- Pulmonary pump
What are the components of the systemic pump?
- Left ventricle
- Left atrium
What are the components of the pulmonary pump?
Right ventricle
Right atrium
Where is the heart located?
The heart lies in the middle mediastinum inside the pericardial sac between 4 segments of the sternum in front and the middle 4 thoracic vertebrae behind.
Where is the apex of the heart located?
The apex of the heart lies in the fifth intercostal space.
Describe the location of the base of the heart.
The base faces posterior, superiorly and to the right.
What is the pericardium?
- A fibroserous sac surrounding the heart and the roots of the great vessels.
- It consists of the fibrous pericardium and the serous pericardium
Describe the fibrous pericardium.
It is a tough connective tissue outer layer that defines the boundaries of the middle mediastinum.
What are the functions of the fibrous pericardium?
- Prevents overstretching
- Provides protection
- Anchors the heart
What are the two constituents of the serous pericardium?
- Parietal pericardium - lines the inner surface of the fibrous pericardium
- Visceral pericardium - adheres to the heart and forms its outer covering
Give the other name of visceral pericardium.
Epicardium
Describe the surfaces of the heart
- Diaphragmatic surface - faces inferiorly towards the diaphragm
- Sterno-costal surface - also called anterior surfaces, is orientated anteriorly facing the sternum
- Right pulmonary surface
- Left pulmonary surface
Which components make up the base of the heart?
- Left atrium
- Small portion of right atrium
- Proximal parts of great veins
Name the great veins
- Inferior vena cava
- Superior vena cava
- Pulmonary veins
What are the surface/external grooves of the heart called?
Sulci (sulcus for sing.)
Describe where the coronary grove/sulcus is located
- It circles the heart, separating the atria from the ventricle.
- It contains the right coronary artery, the small cardiac vein, the coronary sinus and the circumflex branch of the the left coronary artery
What is another name for the coronary groove?
Atrio-ventricular sulcus
Describe the location of the anterior interventricular sulcus.
It is on the sterno-costal surface of the heart and contains the anterior interventricular artery and the great cardiac vein
Describe the location of the posterior interventricular sulcus
It is on the diaphragmatic surface of the heart and contains the posterior interventricular artery and the middle cardiac vein
Describe the characteristics of the right atrium
- Has orifices of the superior vena cava from superior and inferior vena cava from inferior
- The right auricle, an appendage, projects supero-medially over the origin of the ascending aorta.
- The fossa ovalis, a shallow, oval scar characterizes the smooth posterior wall
- Transverse muscular ridges called pectinate muscles or musculi pectinati run to a vertical ridge called the crista terminalis on the anterior wall.
- The orifice of the coronary sinus lies between the orifices of the inferior vena cava and the tricuspid valve. It drains venous blood from the heart muscle.
- The tricuspid opening is also found and is controlled by the tricuspid valve. It controls blood flow from the right atrium into the right ventricle.
Describe the characteristics of the right ventricle.
- Inner surface has muscular ridges called the trabeculae carneae except in the funnel-shaped infundibulum.
- The infundibulum is a funnel-shaped opening of the right ventricle which extends upwards to the pulmonary trunk.
- The orifice of the infundibulum is controlled by the pulmonary semilunar valve.
- the tricuspid valve has 3 cusps which lie in the ventricle and are attached to cone-shaped papillary muscles by chordae tendinae.
- Close to the apex lies a muscular bundle called the septo-marginal trabeculae or moderator band that stretches from the interventricular septum to the papillary muscle of the anterior wall
What is the right auricle?
An appendage that projects supero-medially over the origin of the ascending aorta from the right atrium
What is the fossa ovalis?
A shallow, oval scar on the posterior wall of the right atrium that formed from the fossa ovale
What are pectinate muscles?
Transverse muscular ridges on the anterior walls of the atria
What structure does the left auricle curl around?
The left border of the pulmonary trunk
What is the function of papillary muscles?
They tense the chordae tendinae and prevent the cusps of the the tricuspid valve from flapping into the right atrium
What is the septo-marginal trabeculae?
A muscular band bundle that stretches from the interventricular septum to the papillary muscles of the anterior wall of the right ventricle
Describe the characteristics of the left ventricle.
- The wall is approximately 3 times thicker than that of the right ventricle.
- The inner wall demonstrates trabeculae carneae except in the aortic vestibule.
- There is an aortic valve that is guarded by 3 semilunar valves
- The interventricular septum is particularly thick and bulges into the right ventricle.
Which 2 structures in the foetus provide detours by which blood bypasses the foetal lungs?
- foramen ovale
- ductus arteriosus
What is the foramen ovale?
An opening in the septum between the right and left atria that diverts blood into the left atrium so that it bypasses the foetal lungs
What is the ductus arteriosus?
A small vessel connecting the pulmonary artery with the aorta to divert blood into the systematic circulation without going through the lungs
What is the function of arteriovenous anastomoses?
They permit direct transfer of blood from the arterial to venous channels, bypassing the capillary bed.
Where do arteriovenous anastomoses occur?
Organs whose functions areintermitted
