Wk5-3 Cardiovascular Embryology Flashcards
Which structure brings oxygenated blood to the embryonic heart?
The umbilical vein
What is the papillary muscle attached to?
The chordae tendinae of an atrioventricular valve
Where is mediastinum?
In the middle of the thorax, separates the two lateral pleural cavities which houses the lung and between the mediastinal pleura which is the membranes that surround the lungs.
What is the subdivision of mediastinum?
Superior and inferior (anterior/middle/posterior)
How is heart positioned?
two-third to the left and one-third to the right
Where is upper border of the heat located?
3rd right costal cartilage, 1cm from sternal line
Where is lower border of the heat located?
lower border of 2nd left costal cartilage, 2.5cm from left sternal line
where is the apex of the heat located?
9cm left of the midsternal line
where is the (right inferior) part of the heart located?
At 7th right sternocostal articulation
What connects aortic arch and left pulmonary artery?
ligamentum arteriosum
Where is mitral valve?
At apex of the heart, 5th intercostal space at the midclavicular line
Where is tricuspid valve?
Lower left sternal border in the 4th/5th intercostal space
Where is aortic valve?
2nd right intercostal space near the right sternal border
Where is pulmonic vale?
2nd left intercostal space near the left sternal border
What are two layers of pericardium?
Outer fibrous pericardium and inner serous pericardium (parietal pericardium which is the inner surface of the pericardium +visceral layer which is the outer surface of the hear, aka epicardium )
What structure is continuous with fibrous pericardium?
Central tendon of the diaphragm, pericardiophrenic ligament
What are the three layers of each heart chamber?
endocardium (endothelium and subendothelial connective tissues, lining membranes of the heart that also covers its valves)
myocardium (cardiac muscle)
epicardium (visceral layer of serous pericardium)
What type of cell make up of epicardium?
Mesothelium
What type of cells make up for serous pericardium?
mesothelium
What is subepicardial layer made of?
Subepicardial layer: lay between myocardium and epicardium.
Made up of loose connective tissue containing coronary vessel, nerve and ganglia.
What is stored in subepicardial layer?
Fat
What are the components of myocardium?
Contractile cells and impulse generating cells
What is the name of the individual muscle cells that make up the myocardium?
Cardiomyocytes
What is the characteristics of cardiomyocytes?
Striated, uninuclear, with one or two branches
Cardiomyocytes are full of what?
Full of myofibrils (contraction) and mitochondria (provide ATP for heartbeat, afford resistance to fatigue)
What is the name of this specialized cardiac muscle fibers that play crucial role in the conduction of electrical signal within the heart?
Purkinje fibers
What is the characteristics of purkinje fibers?
- Full of glycogen as stored energy
- Larger diameter fibers
- Gap junction (rapid transmission of electrical impulse across the heart)
- pale-staining due to low myofibril content
Do purkinje fibers contain alot myofibrils and mitochondria like cardiomyocytes?
No. Purkinje fibers have fewer myofibrils because their primary role is conduction, not contraction.
Which muscle is responsible for atrium contraction?
Pectinate muscles found in the wall of the atria, particularly in the right atrium.
What supports the structure of ventricles? What is another function of this structure?
Trabeculae carneae, it also maintain integrity of myocardium.
Where would you find trabeculae carneae and what’s the characteristic of it?
It will be found on the inner walls of the ventricles. It has irregular, mesh-like ridges muscular column.
Where would you find papillary muscles?
In the ventricles of the heart
What is the function of desmosomes in intercalated discs ?
They hold cells together and prevent cells from separating during contraction.
What is the function of gap junctions in intercalated discs ?
They directly connect the cytoplasm of two cells which allow ions to pass from cell to cell. They electrically couple adjacent cells. They allow heart to be a functional syncytium, a single coordinated unit.
What do fascia adherens do in intercalated disc?
They anchor actin filaments, help to transmit contractile forces from one cells to another which ensures that the force generated by muscle contraction is distributed across the entire heart muscle, enabling effective heartbeats.
What are the three components of endocardium?
- simple squamous epithelium (endothelium)—innermost layer
- Fibroelastic connective tissue with scattered fibroblasts (beneath endothelium)
* provide support and flexibility to the endocardium —-middle layer - subendothelial fibroelastic connective tissue containing small blood vessels, nerves and purkinje fibers ——outermost layer
What does endocardium form?
Endocardium form the lining of atria and ventricles.
Which type of cells make up the endocardium?
Endocardial cells
What do endocardial cells form?
Endocardial cells form the inner lining of the AV and semilunar valves to ensure they open and close efficiently during the cardiac cycle
What do intercalated discs do?
Connect cardiac muscle fibers
True or False: cardiac muscle fibers contain sarcomeres (all presence of Z discs, A bands and I bands).
True. Sarcomeres, the fundamental contractile units of muscle.
How is sarcoplasmic reticulum in cardiac muscles fibers compared to skeletal muscle?
Cardiac SR is simpler than in skeletal muscle
How is T-tubules in cardiac muscle cells compared to skeletal muscle?
Cardiac T-tubules are larger
Where are cardiac muscle fibers anchored to?
Cardiac muscle fibers are anchored to the fibrous skeleton of the heart.
What materials make up of fibrous skeleton of the heart?
Dense collagen/fibroblastic tissue
What are the component of four fibrous rings?
- Fibrous coronet of pulmonary valve (support pulmonary valve)
- Fibrous coronet of aortic valves (support aortic valve)
- Left fibrous ring: support mitral valve
- Right fibrous ring: support tricuspid valve
- Fibrous rings surround and support the orifices of the heart valves.
What are the components of Fibrous trigone?
- Right fibrous trigone (between right and left fibrous rings, connect tricuspid valves to aortic valves, which connect the right side of the heart with the aortic valve)
- Left fibrous trigone (connect aortic rings and mitral valves, which connect left side of the heart with the aortic valve)
- Fibrous trigone: connections between rings
What does membranous interatrial septa do?
It separates the atria of the heart
What does membranous interventricular septa do?
It separates left and right ventricles
What does fibrous skeleton do to the orifices of the AV and semilunar valves?
Fibrous skeleton keep s the orifices of the AV and semilunar valves patent (open) and prevent them from being overly distended (trigones)
What does fibrous skeleton provide attachments for?
Fibrous skeleton provides attachments for the leaflets & cusps of the valves, also provides attachments (origin and insertion for the myocardium)
Fibrous skeleton forms an electrical insulator (An insulator is a material or structure that prevents or limits the passage of energy). What does it exactly do?
It separates the impulses of the atria and ventricles.
It surrounds and provides passage for the initial part of the AV bundle (bundle of his)— the conducting system of the heart.
SA node and AV node are located in left or right atrium?
Right
Which side of myocardial walls is more trabeculated?
Right side of myocardial walls is more trabeculated.
What side of myocardial walls contain less muscle mass?
Right side of myocardial walls
Which side of myocardial walls is thinner?
Right side of myocardial walls
What is the name of right AV valves?
Tricuspid valves
What is the name of left AV valves?
Mitral/bicuspid valve
How many leaflets and papillary muscles are there in tricuspid?
3 leaflets
3 sets of papillary muscle: anterior/posterior/septal
How many leaflets and papillary muscles are there in mitral?
2 leaflets
2 sets of papillary muscle: anterior/posterior
What separates right and left atria?
Interatrial septum
What is a special feature of interatrial septum?
Fossa ovalis
what separates right and left ventricles?
interventricular septum
what is the characteristics of inferior interventricular septum?
large & muscular
what is the characteristics of superior interventricular septum?
small & membranous
what does interventricular septum corresponds to?
anterior & posterior IV sulcus
what is auricles and what do they do?
Small ear-shaped appendages attached to the atria.
Increase the capacity of the atrium which allow the atria to hold a greater volume of blood.
What is the pacemaker of the heart and where is it located?
sinu-atrial node, located near the opening of the superior vena cava in the right atria
How does the contraction signal from sinu-atrial node spread?
The contraction signal spreads myogenically in both atria.
The electrical signal generated by the sinu-atrial node causes the atria to contract. The signal spread through the muscle fibers of both atria without the need for nerves to propagate the signal.
What is the innervation of sinu-atrial node and what inhibits it?
Innervated by sympathetic nervous system
Inhibited by parasympathetic nervous system
where is atrioventricular node located?
On the floor of the right atria near the opening of the coronary sinus, at the junction with interventricular septum.
What is the role of AV node?
AV node is the only electrical connection between the atria and the ventricles. This slows down the conduction of the electrical impulses, allowing the ventricles time to fill with blood before contracting.
How does AV node distribute the signal to the ventricles?
AV nodes distributes the signal to the ventricles through the AV bundle (bundle of His)
What speeds up/slows down the electrical conduction produced by AV node?
Sympathetic stimulation speeds up conduction.
Parasympathetic stimulation slows it down.
What is the pathway of AV bundle?
It passes from the AV nodes through the fibrous skeleton of the heart and along the membranous part of interventricular septum
