Lecture 5: Anatomy of the Heart, Part 2 Flashcards
How many Heart valves are there?
4
What are the names of the 2 types of heart valves?
- Atrioventricular (AV) valves
- Semilunar valves
What is the function of the Atrioventricular valves?
Prevent blood returning to Atria during ventricular contraction
What is the name of the right Atrioventricular valve?
Tricupsid valve
What is the name of the left Atrioventricular valve?
Bicupsid (mitral) valve
How many cusps does the tricuspid valve have?
3
How many cusps does the bicuspid valve have?
2
What happens to the heart during Diastole?
Ventricular muscles relax and blood fills into the Ventricles from the Atria
What valves are open/closed during Diastole?
Open - Atrioventricular
Closed - Semilunar
What happens to the heart during (Ventricular) Systole?
Ventricular muscles contract and blood is pumped out of the ventricles into the arteries
What valves are open/closed during Systole?
Open - Semilunar
Closed - Atrioventricular
What closes the Atrioventricular valves during Systole?
The backwards pressure of blood pushing on the valves
What opens the Semilunar valves during Systole
The forward pressure of blood pushing on the valves
Whats a simple description of Systole?
Blood flowing out of the heart due to contraction
Whats a simple description of Diastole?
Blood flowing into the heart due to relaxation
What is the function of the Semilunar valves?
Prevent blood returning to ventricles during filling (Diastole)
What is the name of the right Semilunar valve?
Pulmonary (Semilunar) valve
What is the name of the left (Semilunar) valve?
Aortic (Semilunar) valve
How many cusps does the Pulmonary/Aortic semilunar valve have?
3
What is bigger the Pulmonary or Aortic valve?
Aortic valve
What happens to blood due to it moving out of the heart through a small valve?
It moves at high pressure/velocity
What happens to blood due to it entering the heart through a large valve?
It moves at lower velocity with less pressure
What are papillary muscles?
Finger like projections of the capillary wall in the heart
What is the chordae tendineae?
Tendon like fibrous cords that connect to the Papillary muscles and Atrioventricular valve cusp
What do the Papillary muscles/Chordae Tendineae do?
They develop pre-tension on the Atrioventricular cusps to prevent heavy slamming due to high pressure
What is the first branch off the Aorta of Systemic circulation?
The Coronary Artery
What are the 2 Coronary arteries?
Right/Left
What does the right Coronary artery supply?
The Right side of the heart and some of the posterior
What does the left Coronary Artery supply?
The left side of the heart
What does the left Coronary Artery divide into?
2
- Circumflex artery
- Anterior interventricular artery
What does the Anterior interventricular Artery supply?
2
- The interventricular septum
- Anterior of the heart
What does the Circumflex Artery supply?
The posterior of the heart
What takes deoxygenated blood that has been used by the heart, away from the heart?
The Cardiac veins
What side of the heart is drained by the small Cardiac vein?
Right side
What side of the heart is drained by the great Cardiac vein?
Left side
What do the Cardiac veins carry blood back into the heart through?
The Coronary sinus
What feature can be determined from a Longitudinal Histological section of Cardiac muscle?
Thin capillary walls to limit distance of diffusion
What feature can be determined from a Transverse Histological section of Cardiac muscle?
They contain lots of Capillaries
What are two features of Cardiac muscle structure?
2
- Striated
- Short, branched cells
How many nuclei are there per Cardiac muscle cell?
one/occasionally two
What is the shape/position of the nucleus in Cardiac muscle cells?
Central and oval shaped
Where are the Cytoplasmic organelles packed in Cardiac muscle cell nuclei?
At the poles of the nuclei
How are Cardiac muscle cells interconnected with neighbouring cells?
Via intercalated disks (ICDs)
What is special about the mitochondria in Cardiac muscle?
Theres lots of them, they are about 20% of the cell volume
Why are the sarcomeres of Cardiac muscles pointed in different angles?
Due to the branching multi direction force that is produced
What are intercalated disks?
The area between Cardio Myocytes
What are the 3 types of junction that form the intercalated disks?
- Adhesion belts
- Desmosomes
- Gap junctions
What do Adhesion belts do?
2
- Link actin to actin
- Allow neighbouring myocytes to contract through physical propagation
What do Desmosomes do?
2
- link Cytokeratine with Cytokeratine
- The cytoskeletons of neighbouring cells
What do Gap junctions do?
Electrochemical communication
What is specific about Gap junction positioning in intercalated disks?
They are placed parallel to the direction of contraction
What does the conduction system of the heart do to the efficiency of heart pumping?
It increases it
What is the Conduction system of the heart responsible for?
2
- Co-ordination of heart contractions
- Atrioventricular valve action
What alters the rate of conduction impulse generation?
Autonomic nerves
Where does the Conduction pathway begin?
At the Sinoatrial node
After the Sinoatrial node where does the conduction pathway pass through?
Internodal pathways
Where do all the internodal pathways reunite?
The Atrioventricular node
Following the Atrioventricular node what do electrical impulses travel through?
Atrioventricular bundle
What does the Atrioventricular bundle branch into?
Right and left bundles
What do the right and left Atrioventricular bundles branch into?
Purkinje fibres
What are Purkinje cells?
Modified cardiac muscle
What is the cytoplasm of Purkinje cells filled with?
Mitochondria and glycogen
What type of junction is largely present in Purkinje cells?
Gap junctions
Where is the nucleus located in Purkinje cells?
Centrally
