The Cardiovascular System Flashcards
(35 cards)
Describe the elements of the thoracic skeleton
- Clavicle/scapula
- Sternum
- True ribs 1-7
- False ribs 8-10
- Floating ribs 11,12
- Costal cartilages
- Thoracic vertebrae
- Diaphram
What 3 parts is the sternum made up of
- Manubrium
- Body
- Xiphoid process
What is the chest cavity divided into
- Median partition (mediastinum)
- Lateral pleura & lungs
Where does the mediastium extend to
- Root of neck above
- Diaphram below
- Sternum anteriorly
- Vertebral column posteriorly
What is the pericardium
A fibro-serous sac that encloses the heart (in the mediastinum) and the roots of the great vessels
Functions:
- Restrict excessive movements of the heart as a whole
- Serve as a lubricated container in which the different parts of the heart can contract
What are the 4 chambers of the heart
- Right ‘pump; = receives deoxygenated, sends to lungs
- Left ‘pump’ = receives oxygenated, sends to body
- Each pump consists of an atrium and ventricle, separated by a valve
What is the structure of the heart
- Left and right atrium
- Left and right ventricle
- Interventricular septum
- Atrioventricular valves
- Superior and inferior vena cava
- Pulmonary trunk
- Left and right pulmonary veins
- Aorta
- System of arteries and veins
- “arteries – away” - blood away from heart, veins blood towards heart
What is the difference between atria and ventricles
- Thin-walled atria receive blood coming into the heart, whereas the relatively
thick-walled ventricles pump blood out of the heart - Greater force required to pump blood through the body than to the lungs, so
muscular wall of left ventricle is thicker than the right - Inter-atrial, interventricular and atrioventricular septa separate the four
chambers of the heart - Internal anatomy of a chamber is critical to its function
What are the functions of the right atrium
- Forms right border of heart
- Receives blood through the SVC, IVC and coronary sinus
- Coronary sinus returns blood from the walls of the heart itself
Describe the anatomy of the right atrium
Crista terminalis
- Ridge on inside between atrium and right auricle
- From SVC to IVC
- Posterior to the wall is smooth
Musculi pectinati
- Anterior to crista terminalis the walls are roughened by bundles of muscle fibres
Fossa ovale
- Marks location of embryonic foramen ovale, which allowed blood to bypass the lungs in fetal circulation
Right auricle
- Ear-like, conical, muscular pouch overlapping the aorta
Atrioventricular orifice
- communication with ventricle
- closed by tricuspid valve
What are the functions of the right ventricle
- Blood entering from right atrium moves in a horizontal and anterior direction
- Outflow tract: pulmonary trunk
- Pulmonary trunk closed by pulmonary valve
– 3 semilunar cusps
Describe the anatomy of the right ventricle
Trabeculae carnae
- Muscular, irregular structures
- A few trabeculae carnae are known as papillary muscles
Tricuspid valve
- Guards atrioventricular orifice
- 3 cusps
Chordae tendineae
Describe the importance of the papillary muscles in the right ventricles
When the ventricle contracts, papillary muscles contract, preventing the cusps from turning inside out into the atrium as intra-ventricular pressure rises
What are the functions of the left atrium
- Forms most of base of heart
- Blood enters X4 pulmonary veins
- Anterior half is continuous with left auricle
– No equivalent to the crista terminalis - Depression on interatrial septum is the valve of the foramen ovale
- Blood moves into left ventricle via atrioventricular orifice
– Guarded by the mitral valve
Describe the anatomy of the left ventricle
- Mitral valve aka
bicuspid valve
– Ant/Post cusps - Papillary muscles
observed as for the right
ventricle
– Ant/Post
Describe the left ventricle
- Anterior to left atrium
- Wall x3 thicker than right ventricle
- Blood passes through AV orifice towards apex
Describe blood flow in left ventricle
- Blood flows into the aortic vestibule
- Guarded by the aortic valve
- Similar in structure to pulmonary valve
- As blood recoils after ventricular
contraction, and fills the aortic sinuses
formed by the cusps, it is forced into coronary arteries
Describe coronary circulation
- The heart is a muscular organ, contracting around once a second
- Needs its own source of oxygen and nutrients
- Supplied by the coronary arteries:
- Two: right and left
- Arise from aortic sinuses of the ascending aorta
- Coronary arteries and branches distributed over surface of heart
- Variability in branches
Describe the right coronary artery
- Arises from aorta and runs forward between pulmonary trunk and right
auricle - Descends almost vertically in the right
atrioventricular groove - At inferior border continues posteriorly
to anastamose with left coronary artery - Offers a marginal branch and a posterior interventricular branch
Describe the left coronary artery
- Usually larger than right
- Arises from aorta and passes forward between the pulmonary trunk and left auricle
- Then enters atrio-ventricular groove and divides into anterior inter-ventricular branch and a circumflex branch
The coronary sinus receives which 4 major tributaries
- Great, middle, small and posterior cardiac veins
- Anterior cardiac veins are very small, draining only the anterior portion of the right ventricle
What are the components of cardiac veins
- Great cardiac vein
- Left marginal vein
- Left posterior ventricular vein
- Coronary sinus
- Middle cardiac vein
- Small cardiac vein
(posterior)
Describe the features of the branches of the aorta
- Ascending within pericardial sac
- Arch lies behind manubrium sterni, infront of trachea
- Arches upwards and backwards
- Becomes continuous with descending aorta at level of sternal angle
- Aortic arch branches:
- Brachiocephalic trunk (divides into right subclavian and right common carotid
- Left common carotid
- Left subclavian
What are the branches of the aortic arch
- Brachiocephalic trunk
- L common carotid
- internal/external carotid arteries
- L subclavian
