# ระบบไหลเวียนเลือด / Circulatory system

เมนูนี้รวมชั้นหัวใจ หลอดเลือดแดง และหลอดเลือดดำ โดยคงโมเดลต้นฉบับและชื่อชิ้นส่วนเดิม การแตะหัวใจยังเปิดข้อมูลและโหมดผ่าดูภายในได้

อนิเมชันใช้ลูกศรเว้นระยะบนหลอดเลือดหลักจริงในโมเดล: หลอดเลือดแดงออกจากหัวใจ หลอดเลือดดำกลับเข้าหัวใจ สีแดงแทนเลือดที่มีออกซิเจนสูง และสีน้ำเงินแทนเลือดที่มีออกซิเจนต่ำ หลอดเลือดแดงปอดจึงใช้สีน้ำเงิน ส่วนหลอดเลือดดำปอดใช้สีแดง สีน้ำเงินเป็นสีสื่อความหมายในแบบจำลอง เลือดจริงไม่ได้เป็นสีน้ำเงิน

The renderer computes an illustrative surface-distance field from an anatomical upstream reference for each vessel component. Aortic arch and descending trunks use explicit upstream references; other vessels infer an inlet near the relevant cardiac chamber. This is a directional teaching animation, not a connected haemodynamic simulation or a measurement of flow velocity, pressure, pulse timing, oxygen concentration or capillary exchange. Complex branch inlets are approximate.

## Cervical artery reconstruction

The donor meshes omit roughly 5–6 cm of the cervical carotid and vertebral arterial courses. Both active body atlases now include smooth educational continuations from the native common carotid to the internal carotid and from the subclavian to the vertebral artery. Endpoints and calibres are registered to each donor's existing vessel surfaces. All original donor vertices are retained. Common and internal carotid continuations retain their original selection identities. Representative external carotid trunks share the same bifurcation and rise anteriorly toward the parotid region. Their distal branches are not reconstructed; the trunk ends indicate the extent of this partial educational reconstruction. These inferred segments are not donor scans and cannot establish patient-specific anatomy. The audit backup and landmark report are in audit/cervical-arteries. Reference: https://www.ncbi.nlm.nih.gov/books/NBK27421/.

Pause retains the current phase and camera. Individual organ isolation and cutaways retain their existing materials. Sparse arrows use two instanced draw calls; oxygenation shading adds no extra vascular draw calls; the faint supporting anatomy is batched in this system view. Source bone and muscle visibility rules remain available in other modes.

Physiology reference: [NHLBI — How Blood Flows through the Heart](https://www.nhlbi.nih.gov/health/heart/blood-flow).

## Heart cutaway

The isolated heart study includes eight native proximal stems: superior and inferior vena cava (into the right atrium), pulmonary trunk (out of the right ventricle), ascending aorta (out of the left ventricle), and four pulmonary veins (into the left atrium). Native triangles are trimmed to short open-ended stems. An inferred inner vessel wall joins the boundary rings without spanning the lumen with a disk. Source anatomy in the body view is unchanged.

Blue indicates low oxygen, red high oxygen. Pulmonary vessels therefore have the opposite oxygenation colors to their systemic counterparts. Directional arrows travel along the short stems and representative intracardiac routes through the atrioventricular valves. Each arrow follows a continuous inlet → atrium → atrioventricular valve → ventricle → outlet path. Rounded line segments avoid spline overshoot and coils. Arrow colors are saturated blue/red; fine guides show the route. Arrows and guides stay visible through walls and cut planes so the route can be tracked. They restart only at the external end of the outlet. Native chamber metadata positions these educational routes; they are not CFD streamlines.

A gentle 1.2% contraction animates the entire heart assembly, its attached stems and cut caps together at about 63 illustrative beats per minute. Clipping planes follow the same transform. Pause freezes the current phase without changing the camera or cut percentage. This is a simplified visual contraction, not simulated atrial/ventricular mechanics or an actual pulse measurement. The initial front cut view tilts slightly upward to expose the open vessel rims; subsequent cut controls retain the user's view.