BIO 004 · Human Anatomy
Blood Vessel Disorders & Fetal Circulation
Block 3 · Module 5: Blood Vessel Disorders and Fetal Circulation
A reference for the blood vessel disorders and fetal circulation video and lab. This page covers atherosclerosis and the common arterial and venous disorders, then the special circulation of the fetus and what its shunts become after birth.
How to use this sheet Toggle the toolbar above. Notes prints the full reference for review. Study prints as a fill-in-the-blank worksheet. Print it, then write each definition while you watch the video or read your book. Quiz me is on-screen typing practice: type the term, click Reveal to check yourself. The comparison grids respond to Study and Quiz too, with a Reveal button on each row.
The Foundations video gives you a complete foundational understanding of this topic, enough on its own for a foundational course. Learn it first, then move on to the Deep dive, which adds the majors-level material: the venous disorders, the fetal shunts, and what each shunt becomes after birth.
- Describe atherosclerosis and how it changes an artery wall.
- Name common arterial and venous disorders.
- Explain how fetal circulation differs from the adult plan.
- Name the fetal shunts and the adult remnant each one becomes.
Your pre-work
Work through these the evening before class. None of it is turned in. It is how you learn the material and build your spaced recall.
This is more than a checklist. Ticking these boxes is the start, not the finish. Committing this material to memory and being able to apply it takes considerable time and repeated effort. You are not done when the boxes are checked. Put in the real hours, and keep coming back for frequent recall and review until the material is genuinely yours.
An atherosclerotic artery
Add a labeled cross-section comparing a healthy artery with one narrowed by plaque.
Fetal circulation
Add a labeled diagram of fetal circulation showing the placenta, umbilical vessels, and shunts.
Shunts before and after birth
Add a side-by-side view of each fetal shunt and the adult remnant it becomes.
An Overview
This page covers two topics. First, the common disorders of blood vessels, which mostly narrow or weaken the vessel wall. Second, fetal circulation, the rearranged plan a fetus uses before its lungs work.
- Healthy vessela vessel with a smooth endothelial lining and a wall that can stretch and recoil
- Vascular disordera disease of a blood vessel; most disorders narrow the lumen, weaken the wall, or let blood pool
- Fetal circulationthe circulatory plan of a fetus, which gets its oxygen from the placenta rather than from its own lungs
- Shunta special vessel or opening that routes blood around an organ; the fetus uses shunts to bypass the lungs and liver
Atherosclerosis
Atherosclerosis is the most important vessel disease, the root of heart attacks and strokes. It is a slow, structural change in the artery wall.
- Atherosclerosisa disease in which fatty plaques build up within the walls of arteries
- Endothelial injurydamage to the smooth tunica intima lining, the starting point of a plaque
- Atheromaalso called a plaque, a deposit of fatty material, cells, and debris within the artery wall
- Narrowed lumenas a plaque grows it bulges inward, narrowing the channel and reducing blood flow
- Arteriosclerosisthe general stiffening and thickening of artery walls; atherosclerosis is its most common form
- Thrombusa clot that can form on a roughened plaque and suddenly block the vessel
Arterial Disorders
Arteries carry blood under high pressure, so their disorders tend to narrow the channel or weaken the wall. Compare the common ones.
| Disorder | What it is | Why it matters |
|---|---|---|
| Aneurysm | a balloon-like bulge in a weakened artery wall | it can rupture; common in the aorta and the arteries of the brain |
| Atherosclerosis | fatty plaque buildup that narrows an artery | the leading cause of coronary artery disease and stroke |
| Coronary artery disease | narrowing of the coronary arteries that supply the heart wall | can starve the myocardium and cause a heart attack |
| Peripheral artery disease | narrowing of the arteries of the limbs, usually the legs | causes pain on walking as the muscles are starved of blood |
| Hypertension | chronically high pressure within the arteries | strains the heart and damages vessel walls over time |
| Stroke | loss of blood supply to part of the brain, from a blocked or burst artery | brain tissue begins to die within minutes |
Venous Disorders
Veins carry blood under low pressure, so their disorders tend to involve failed valves and pooled or clotted blood. Compare the common ones.
| Disorder | What it is | Why it matters |
|---|---|---|
| Varicose veins | superficial veins that become twisted and swollen when their valves fail | blood pools and the veins bulge visibly, most often in the legs |
| Deep vein thrombosis | a blood clot in a deep vein, usually of the leg | the clot can break free and travel through the bloodstream |
| Pulmonary embolism | a clot, often from a deep vein, that lodges in an artery of the lung | a life-threatening emergency that blocks blood flow to the lung |
| Phlebitis | inflammation of a vein | causes pain, redness, and tenderness along the vein |
| Hemorrhoids | varicose veins of the rectal and anal region | a common cause of rectal discomfort and bleeding |
| Chronic venous insufficiency | long-term failure of the valves of the leg veins | leads to persistent swelling and skin changes in the lower leg |
Fetal Circulation, an Overview
Before birth, a fetus does not breathe air or digest food, so its circulation is rearranged. Oxygen and nutrients come from the placenta, and blood is routed around the organs that are not yet in use.
- The placentathe organ where fetal blood picks up oxygen and nutrients from the mother and gives up wastes
- Umbilical cordthe cord connecting the fetus to the placenta, carrying the umbilical vessels
- The lungs are bypassedthe fetal lungs are collapsed and not used for gas exchange, so most blood is routed around them
- The liver is largely bypassedmuch fetal blood skips the liver, since the placenta handles that filtering
- Three shuntsthe ductus venosus, the foramen ovale, and the ductus arteriosus, the detours that route blood around the liver and lungs
The Fetal Vessels and Shunts
Five special structures carry and reroute fetal blood. Compare what each one is and what it does.
| Structure | What it is | What it does |
|---|---|---|
| Umbilical vein | a vein in the umbilical cord | carries oxygen-rich blood from the placenta to the fetus |
| Ductus venosus | a shunt passing through the fetal liver | lets most blood bypass the liver and flow straight toward the inferior vena cava |
| Foramen ovale | an opening in the interatrial septum | lets blood pass directly from the right atrium to the left atrium, bypassing the lungs |
| Ductus arteriosus | a short vessel between the pulmonary trunk and the aorta | lets blood bypass the lungs by shunting it from the pulmonary trunk into the aorta |
| Umbilical arteries | two arteries in the umbilical cord | carry oxygen-poor blood from the fetus back to the placenta |
The Shunts After Birth
At birth the lungs inflate and the placenta is cut off. Each fetal shunt is no longer needed, closes, and is left behind as a small ligament or remnant. Compare each one with what it becomes.
| Fetal structure | Adult remnant | Note |
|---|---|---|
| Umbilical vein | the ligamentum teres, the round ligament of the liver | runs in the free edge of the falciform ligament |
| Ductus venosus | the ligamentum venosum | a fibrous cord on the inferior surface of the liver |
| Foramen ovale | the fossa ovalis | a shallow oval depression in the interatrial septum |
| Ductus arteriosus | the ligamentum arteriosum | a short cord between the pulmonary trunk and the aorta |
| Umbilical arteries | the medial umbilical ligaments | paired cords on the inner surface of the anterior abdominal wall |
See also: Blood Vessels, Structure and Types for the healthy vessel, and The Lymphatic System, the next page in this block.
Study questions
Work on answering these in writing, in your own words. They are the questions to bring to class, and good practice for the reasoning the exams ask for.
- Compare an aneurysm and an atherosclerotic plaque by what each does to the vessel wall.
- Explain, anatomically, why a deep vein thrombosis is dangerous if part of it breaks loose.
- Why are varicose veins a problem of the veins and their valves rather than the arteries?
- Contrast an ischemic and a hemorrhagic stroke by what happens to the blood vessel.
Step 2 . Retrieval check
Now explain it back, in your own words.
In 60 words or more, pull together what the video just taught you. Include the key concepts. This is the point where the learning actually sticks. After you submit, your spaced-recall cards for this topic unlock.