The heart Flashcards
What valve is the tricuspid valve?
Valve between right atrium and right ventricle
Describe the valve between the right ventricle and the pulmonary trunk
- Pulmonary valve
- Has 3 semilunar cusps
Describe the valve between the left atrium and left ventricle
- Mitral valve
- Bicuspid
Describe, in full, the valve between the left ventricle and the aorta
- Aortic valve
- 3 semilunar cusps
- Guards the aortic orifice
- Aortic sinues directly above
What are the aortic sinuses and what is the importance to coronary arteries?
- Anatomical dilations of the aorta (pockets)
- Each sinus is one valve of the aortic valve
- The origin of the left and right coronary artery start in one of the sinus
What are the 3 branches from the aortic arch? (right to left)
1) Brachiocephalic artery
2) Left common carotid artery
3) Left subclavian artery
What are the 2 branches from the brachiocephalic artery? (right to left)
1) Right subclavian
2) Right common carotid artery
From the heart, what are the branches of the superior vena cava?
Right and left brachiocephalic vein
What are the branches of the brachiocephalic veins?
1) Subclavian vein (most laterally)
2) Internal jugular vein (more medially)
What 4 things drain into the right atrium?
1) Inferior vena cava
2) Superior vena cava
3) Coronary sinus
4) Anterior cardiac vein
What does the anterior cardiac vein do?
Collect blood from the right ventricle and drain into the right atrium
Where does the coronary sinus receive blood from?
- Great cardiac vein
- Middle cardiac vein
- Small cardiac vein
- Oblique vein
What does the coronary sinus do and where is it seen?
Collects deoxygenated blood from the heart muscle itself and delivers it to the right atrium
- Mainly seen on the posterior of the heart, in the coronary sulcus
- Just to the left of the vena cava
What does the pericardium contain?
- Heart and its great vessels
- Pericardial fluid
Function of the pericardium?
To lubricate the moving surfaces of the heart
What is the ligamentum arteriosum?
The remnants of the foetal ductus arteriosus, which connects the pulmonary trunk to the proximal descending aorta - to bypass the foetal non-functioning lungs
What do the coronary arteries do?
Give blood supply to the heart
Where are the coronary arteries hidden?
Under auricular appendages
Where do the main branches of the coronary arteries lie?
In the inter-ventricular (anterior - left and posterior- right) and atrioventricular grooves
Describe the pathway of the right coronary artery
- Pathway
- Branches
- Largest branch and pathway
- Directed to the right and passes to the posterior part of the heart within the CORONARY SULCUS
- Sends branches along its path
- The largest branch is the posterior inter-ventricular artery, which courses towards the apex or the heart
What is the coronary sulcus and what does it contain?
Separates the atria from the ventricles
Contains:
- Right coronary artery
- Coronary sinus
- Small cardiac vein
- Circumflex artery
Describe the pathway of the left coronary artery
- Pathway
- Branches
- Largest branch and pathway
Directed to the left and then divides into 2:
1) An anterior interventricular branch - descends towards the apex
2) A circumflex branch - passes posteriorly to the back of the heart
What are the auricles of the heart and what are their function?
- Attached to each of the anterior surfaces of the outside of the atria
- Appendages
- Function is to increase the capacity of the atria
What does the inside of the atria look like?
- Smooth area
- Auricle is marked by muscle ridges - pectinate muscles
What are the pectinate muscles?
Parallel muscle ridges on the inside of the auricle in the artia
What is the full structure of the tricuspid valve?
- Cups
- How attached to the heart wall
3 cusps:
- Anterior
- Posterior
- Septal
- Attached to the wall by chordae tendinae and papillary muscles
Which ventricle is the the thickest?
Left ventricle
What are trabeculae carneae?
Irregular muscle elevations, marking the inner inflow tract pathway
Found in the ventricles
What are papillary muscles?
Muscles in the ventricle which project into the lumen of the ventricle and attach to the valve by chordae tendinaea
Which atria has thicker walls and is smaller?
The left atria
What opens into the left atrium?
4 pulmonary veins, bringing oxygenated blood from the lungs
How is the mediastinum divided?
By a theoretical horizontal line from the sternal angle to the lower border of T4
- Divides it into the superior and inferior
Inferior divided further into:
- Anterior
- Middle
- Posterior
What mediastinum is the aortic arch contained within?
Superior mediastinum
At what level does the aorta give off its 3 main branches?
T4
What is in the middle mediastinum?
The pericardium
Heart
Great vessels
Where does the posterior mediastinum start and end?
T5- T12
What does the posterior mediastinum contain?
The descending aorta
What is the base of the pericardium fused with?
The central tendon of the diaphragm
What is the structure of the pericardium?
2 layers:
1) Fibrous
- Dense connective tissue
2) Serous layer:
- Visceral layer (epicardium)
- Parietal layer
What happens to the heart when it develops?
It invaginates into the serous sac, forming a visceral and a parietal layer
What do the common carotid arteries divide into?
Internal and external carotid arteries
How is the pericardium attached to the sternum?
Via the sternopericardial ligament
Where does the diaphragm hang down to?
- Posteriorly
- Anteriorly
- In the middle
T12 posteriorly
T10 anteriorly
T8 in the middle
Where does the inferior vena cava enter the diaphragm?
T8
Where does the oesophagus enter the diaphragm?
T10
Where does the aorta enter the diaphragm?
T12
enters behind the diaphragm, doesn’t pierce
What are the surface projections of the heart? (right to left, top to bottom)
3rd costal cartilage
2nd costal cartilage
6th costal cartilage
5th intercostal space
Which side of the liver is higher than the other?
Right side
Where does the sinoatrial node receive its nerve impulse from?
The Vagus nerve, just to the right of the opening of the superior vena cava
What is modified cardiac muscle?
- Conduts nerve impuse from the SA to the AV node
And then through the bundle of His
Where does the electrical impulse of the heart travel once it has travelled down the bundle of His?
Into the right and left branches which run immediately beneath the endocardium
Where does the AV node lie?
In the atrial septum, above the opening for the coronary sinus
Describe the circulation in the fetus
- Deoxygenated blood to the placenta by UMBILICAL ARTERIES
- Blood is nourished and oxygenated at the placenta, leaves placenta via the UMBILICAL VEIN
- Much of the oxygenated blood bypasses the liver through the DUCTUS VENOSUS - to the inferior vana cava
- Blood enters the right atrium
Right atrial blood bypasses the lungs by 2 routes:
1) Across to the LEFT ARTIUM via the FORAMEN OVALE
2) To the right ventricle, out the pulmonary artery and through the DUCTUS ARTERIOSUS to reach the aorta
What happens to the circulation at birth and why?
- Expansion of the lungs leads to increased blood flow in the pulmonary arteries
- Causes a pressure change in the artia
- Closes the foramen ovale
- Functional closure of the ductus arteriosis, due to contraction of the muscular wall
What does the foramen ovale become at birth?
The fossa ovalis
What does the ductus arteriosus become at birth?
The ligamentum ateriosus
What do the umbillical ARTERIES become at birth?
They become fibrosed to form the MEDIAL UMBILICAL LIGAMENTS
What do the umbillical VEINS become at birth?
Become fibrosed to form the LIGAMENTUM TERES
What does the ductus venous become at birth?
Forms the LIGAMENTUM VENOSUM
What proportion of people have a balanced distribution of left and right coronary arteries?
70%
What determines the dominance of the coronary arteries?
- Which arteries contribute to the posterior descending artery
- Which artery supplies the AV node
What proportion of people have a dominance of left coronary arteries?
10-15%
What proportion of people have a dominance of right coronary arteries?
15-20%
