Lecture 47 - Cardiovascular System 1 Flashcards
What is the origin of the diaphragm?
Where is the insertion?
The circumference - ie all the way around
The insertion is in the centre of the diaphragm
What does the pericardium attach to?
The diaphragm insertion
Central tendon of the diaphragm
Describe the orientation of the muscle fibres in the diaphragm
Muscle fibres go towards the centre from the circumferential diaphragm
What limits diaphragmatic descent?
The heart and the vessels that are attached
What is the pericardium made of?
External: Outer fibrous pericardium
Internal: serous pericardium (single layer of serous membrane)
What do we always see in vista that expand and contract
A single layer of serous membrane lining the surface and the surface of the viscus
- parietal
- serous
Friction free
What lies between the parietal and visceral serous membranes?
Pericardial cavity
Contains serous fluid
Describe the path cutting through the pericardium
Fibrous pericardium Parietal serous membrane Pericardial cavity Visceral serous membrane Viscus
What do we see on the anterior aspect of the heart?
Right sided chambers
On the right side: right atrium
On the left side: right ventricle
Also, a little bit of the left ventricle on the left border
Why are the right chambers present on the anterior surface?
Rotation of the heart during development
How do we differentiate the right atrium and ventricle externally?
Sulci
Anterior AV sulcus
Coronary sulcus
How do we differentiate the right and left ventricles externally?
Sulcus
Anterior interventricular sulcus
Where is the apex of the heart?
What is it made up of?
Anterior aspect
Right and left ventricles
What are we feeling, when we feel our heart beat externally?
Apex of the heart beating against the anterior chest wall in the fifth intercostal space
Mid-Clavicular line, then drop down to the fifth intercostal space
Where is the base of the heart?
At the top
Where all he vessels emerge
How do we differentiate the left atrium and ventricle externally?
Coronary sulcus
Posterior aspect of heart
Where does blood come from that enters the right atrium?
How does this affect the structure
It is a receiving chamber:
Receives blood from the vena cavae
Thin muscle wall
What is present on the anterior interior surface of the right atrium?
Musculi pectinati
Muscular ridges
Describe the posterior internal wall of the right atrium
Sinus venarum
Smooth
Do the musculi pectinati slowly wave towards the back?
No, abruptly stop.
This is the:
Crista terminalis
What is the name of the posterior wall of the right atrium?
What is on the other side?
Interatrial septum
Connects with the left atrium
The right atrium receives blood from:
The entire body apart from the blood itself
Are there valves in the vena cavae?
Superior VC: no, drops in from above
Inferior VC: rudimentary valve
What does the IVC carry?
Blood from everything below the diaphragm
Where does blood from the heart enter the right atrium?
Coronary sinus
On the smooth posterior wall (sinus venarum)
Between IVC and tricuspid valve
Whee does blood flow from the right atrium in a foetus?
From right atrium to left atrium through the:
foramen ovali
Saves going through the lungs
What happens to the foramen ovali after birth?
Flap comes over, forming
Fossa ovali
Seen as a pit
Which valve separates the right atrium and right ventricle
The tricuspid valve
How do we distinguish the posterior and anterior aspect of the heart
Atrial appendages (auricles) are both on the anterior surface of the heart, near the bottom of the great vessels
Describe the muscle wall in the ventricle
Much thicker muscle than atrium
Where does blood go from the right ventricle?
What guards this flow?
Into the pulmonary artery
Pulmonary valve
Describe the surface of the interior walls of the right ventricle
Trabeculae carnae all the way around
Except just below the pulmonary valve:
- Conus arteriosus
- Or Infundibulum
Give an analogy of the surface of the right ventricle
Like bookshelves running along the wall
Apart from three shelves
These start on the wall and come out into the ventricle, called papillary muscle
Where are the papillary muscles?
Right ventricle
Start on interior wall and project into the centre of the cavity, to the
Chordate tendinae
What do the chordae tendinae connect to?
Papillary muscle
Tricuspid valve
Describe the muscle and surface of the left ventricle wall
Thickest muscle wall
Trabeculae carnae
What is the valve between the left atrium and ventricle?
Mitral valve
Only two cuspids
How many papillary muscles in the left and right ventricles?
Left: two
Right: three
Describe the surface and muscle of the left atrium
Thin muscle wall
Smooth
Apart from the auricle going around to the anterior surface
Why are the atria thin walled?
Because they are receiving chambers
Where is the blood coming from, that comes into the left atrium?
The lungs
Pulmonary vein
What plane does the fibrous skeleton lie in?
What does this mean?
Sagittal plane
The muscle of the atria and ventricles are electically isolated
Why have a fibrous skeleton?
- Anchors atrial and ventricle muscle: separated electrically
- Attachment for base of valve cusp
What attaches to the fibrous skeleton?
The mitral and tricuspid valves
Where are the coronets?
Surround the semi-lunar valves
Compare the atrial and ventricular surfaces of the cusps of the valves
Ventricular: rough
Atrial: smooth
What causes the atrioventricular valves to open and close?
Describe the flow from Atrium to ventricle
Passive process
Opening: pressure of blood in the atrium opens the lungs
Then, flow from high pressure to low pressure from atrium into the ventricle
Closing: slam shut when blood has flowed in
What causes opening and closing of the pulmonary and aortic valves?
High pressure of blood due to the contraction of the ventricular muscle pushes the cusps up and to the side
Slam shut when pressure drops
What prevents blood flowing back into the atria when the ventricles contract?
The chordae tendinae fold the AV valves from opening
How are the valves in the aorta and pulmonary trunk different from AV valves?
They are semilunar valves
Describe the cusp attachments of the semilunar valves
Cusps supported by the two fibrous coronets
The cusps attach to the very start of the pulmonary trunk and aorta
Where are the origins of the coronary arteries?
At the very base of the aorta
Just after the aortic valve
Where is the SA node located?
At the top of the crista terminalis
Near opening of SVC
What does the SA node do?
Generates an electrical impulse that spreads throughout the atrium, causing contraction of the artium
What happens to the electrical conductance at the crista terminalis?
Stops, due to fibrous skeleton
Where does the electrical impulse that goes through the ventricle originate?
Where is it located?
AV node
Situated at the fibrous skeleton
How is the impulse conducted through the ventricles?
Specialised tissue:
Bundle of His
Describe the general innervation of the heart
Where is it?
Parasympathetic and sympathetic
Cardiac Plexus at the base of the heart
