Title: Anatomy / 4 Cardiovascular system

Q: parts of cardiovascular system
A: The cardiovascular systems consist of the:
- Heart;
- Vessels;
- Blood;
- Blood pressure

Q: blood vessels: layers of vessel-wall
A: The wall of blood vessels generally consists of the following layers:
1. Intima: innermost layer;
2. Media: muscular middle layer;
3. Adventia: The outermost layer, which contains its own small blood vessels to supply the wall

Q: difference
between veins and arteries
A: Arteries:
- Contain an internal & external elastic membrane;
- Have a significantly thicker muscle layer;
- transport oxygen-rich blood (exception: pulmonary artery);
Veins:
- Have no elastic membranes;
- Thinner muscle layer;
- Contain venous valves to prevent the backflow of blood;
- transport oxygen-poor blood (exception: pulmonary vein)

Q: heart layers
A: endocardium: innermost layer, composed of endothelial cells, lining the heart chambers;
myocardium: thick, muscular middle layer responsible for contraction and pumping blood;
epicardium: outermost layer, also part of the pericardium, containing blood vessels and nerves;

Q: heart shape
& orientation
A: Main features: It consists of a cardiac basis (base) and a cardiac apex (tip).
Orientation: During fetal development, the heart undergoes a 90° rotation.

Q: heart parts
A: The heart is built in 2 halves. Each chamber contains one atrium (with an auricle) and one ventricle. In between the halves there is the so-called septum.

Q: heart conduction
system (incl. Koch triangle)
A: Conduction system:
- sinuatrial node;
- atrioventricular node;
- bundle of his;
- tawara branches;
- purkinje fibers;
Koch’s triangle: Is the anatomical area containing the AV node (Its borders are the Tendon of Todaro, the ostium of the coronary sinus, and the septal leaflet of the tricuspid valve)

Coronary
vessel

Q: circulatory
system: parts
A: - High-pressure system: Primarily the systemic arteries;
- Low-pressure system: Includes the veins, right heart, and pulmonary circulation;
- Pulmonary circulation: The "small" circuit between the heart and lungs;
- Systemic circulation: The "large" circuit supplying the rest of the body;
- Portal circulation: Specialized circuit for nutrient absorption from abdominal organs;
- Fetal circulation: The specialized system used before birth;

Q: circulatory
system: fetal
circulation
A: Fetal circulation is a special blood flow system that allows the fetus to receive oxygen and nutrients from the placenta instead of the lungs, which are not yet functioning. After birth, when the baby takes its first breath, these shunts close and the circulation changes to the normal postnatal pattern;
ductus arteriosus: a vessel connecting the pulmonary artery to the descending aorta, allowing blood to bypass the lungs;
foramen ovale: an opening between the right and left atrium, enabling oxygenated blood to bypass the non-functional fetal lungs;
ductus venosus: a vessel that shunts oxygen-rich blood from the umbilical vein directly to the inferior vena cava, bypassing the liver

Q: circulatory
system: sequence
of circulation
A: Pulmonary Circuit (Deoxygenated): Right atrium → tricuspid valve → right ventricle → pulmonary valve → pulmonary trunk → left/right pulmonary arteries → capillaries (lungs) → pulmonary veins → left atrium.
Systemic Circuit (Oxygenated): Left atrium → mitral valve → left ventricle → aortic valve → aorta → arteries → arterioles → capillaries → venoles → veins → superior/inferior vena cava → right atrium.
Portal Circuit: Arteries of abdominal organs → nutrient absorption → portal vein → liver → hepatic veins → inferior vena cava.
Lymphatic Drainage: Fluid in extracellular space → lymph capillaries → lymph vessels (with intersecting lymph nodes) → thoracic duct or right lymphatic duct → superior vena cava (venous system).

Header: heart layer
Remarks: pericardium

Header: heart layer
Remarks: epicardium

Header: heart layer
Remarks: myocardium

Header: heart layer
Remarks: endocardium

Header: heart layer
Remarks: coronary vessels

Header: heart valves
Remarks: mitral valve

Header: heart valves
Remarks: aortic valve

Header: heart valves
Remarks: tricuspid valve

Header: heart valves
Remarks: pulmonary valve

Remarks: aorta

Remarks: pulmonary trunk

Remarks: superior vena cava

Remarks: inferior vena cava

Remarks: pulmonary veins