Term
¡(Vagus or accessory) Innervates all of the organs in the thorax and abdomen |
|
Definition
|
|
Term
¡The heart and major vessels develop from the (somatic or splanchnic) mesoderm.
¡Most non-axial mesoderm also contributes to blood vessels. |
|
Definition
|
|
Term
¡Arteries develop from the (dorsal or ventral) aorta (2 tubes that fused)
¡Dorsal aorta has branches
§Posterolateral-segmental arteries of the body and intercostal arteries
§Lateral-(renal or cardiac) arteries
§Ventral-vitilline and umbilical arteries-eventually celiac, SMA, IMA |
|
Definition
|
|
Term
¡In the head and neck the arteries develop from aortic (arches or benches)
¡The aortic arches remodel to form the adult pattern of vessels in the adult head and neck |
|
Definition
|
|
Term
Major vessels at (4 or 5) weeks
¡The newly fused (dorsal or ventral) aorta supplies blood to the head and the body
¡The forming heart pumps blood to the head and body
§The outflow tract of the heart is the truncus arteriosus.
¡
§The terminal part of the truncus is called the (aortic bursa or sac), where the aortic arches arise |
|
Definition
|
|
Term
Major vessels at 4 weeks
¡The aortic arches are blood vessels within the (pharyngeal or vitelline) arches
§They connect with the dorsal aorta on each side around the pharynx
§They become major arteries in the adult |
|
Definition
|
|
Term
Major vessels at 4 weeks
¡The dorsal aorta gives off (vitelline (yolk) or pharangeal sac) arteries and umbilical arteries
§Vitelline arteries supply the dorsal aorta
§Umbilical arteries take (deoxygenated or oxygenated) blood from the fetus back to the mother |
|
Definition
vitelline (yolk)
deoxygenated |
|
|
Term
Major vessels at 4 weeks
¡There are three sets of veins:
§(umbilical, cardinal, or vitelline) veins (anterior and posterior)- drain the head and body wall
§(umbilical, cardinal, or vitelline) veins- drain the yolk sac
§(umbilical, cardinal, or vitelline) vein bring blood from the mother (through the placenta) to the embryo |
|
Definition
cardinal
vitelline
umbilical |
|
|
Term
¡All three sets of veins on each side flow into the right and left horns of the sinus venosus (C)
|
|
Definition
|
|
Term
¡Vessels form in two ways:
§(Vasculogenesis or Angiogenesis): vessels form in situ by coalescence and differentiation of mesoderm cells into endothelial tubes
§(Vasculogenesis or Angiogenesis): new vessels sprout from existing ones. |
|
Definition
Vasculogenesis
Angiogenesis |
|
|
Term
¡(Vasculogenesis or Angiogenesis) is how the heart and major vessels form.
¡
¡(Vasculogenesis or Angiogenesis) is how smaller vessels form.
¡
¡Many of the vessels formed by angiogenesis develop as new organ systems differentiate and need to be supplied |
|
Definition
Vasculogenesis
Angiogenesis |
|
|
Term
¡Molecular signals for vessel formation involve vascular endothelial growth factors (VEGFs) and their receptors. (C)
|
|
Definition
|
|
Term
¡There are five well-developed aortic and pharyngeal arches
¡
¡ Each functioning pharyngeal arch contains an aortic arch.
¡
¡The aortic arches differentiate into vessels supplying the head and neck and upper limbs. |
|
Definition
|
|
Term
Each Pharyngeal Arch Contains an Aortic Arch |
|
Definition
|
|
Term
¡The aortic arches are numbered I-VI, but the fifth either never forms or is very rudimentary.
¡The arches are never all present simultaneously.
¡
¡ The most (cranial or caudal) ones form and then differentiate as more (cranial or caudal) ones are forming |
|
Definition
|
|
Term
¡Some parts of the arches and dorsal aorta undergo programmed cell death as the vessels regress.
¡Major vessels are formed by aortic arches:
§ third
§fourth
§ sixth |
|
Definition
|
|
Term
¡AA1: (Maxillary artery or Carotid system)
¡AA2: Stapedial, hyoid
¡AA3: (Maxillary artery or Carotid system)
¡AA4L: (Arch of aorta or Subclavian)
¡AA4R: (Arch of aorta or Subclavian)
¡AA5: Disappears
¡AA6: Pulmonary arteries and ductus arteriosus (L) |
|
Definition
Maxillary artery
Caritid system
arch of aorta
subclavian |
|
|
Term
¡Sixth AA has nerves (vagus CNX) that wrap around it on both the right and left side
¡Sixth AA becomes the (left or right) pulmonary artery and the ductus arteriosis on the left side
§CNX-left recurrent laryngeal nerve around the DA
¡Sixth AA becomes the right pulmonary artery and a small part of the right subclavian artery
CNX-right recurrent laryngeal nerve around the right subclavian |
|
Definition
|
|
Term
¡Umbilical arteries remain paired and initially arise from the (aorta or subclavian).
§ Later in development, their connection is via the common iliac arteries. |
|
Definition
|
|
Term
Umbilical arteries
¡After birth,
§ the (proximal or distal) segments of the umbilical arteries are retained as the internal iliac and superior vesicular arteries
§ (proximal or distal) portions become fibrous to form the medial umbilical ligaments. |
|
Definition
|
|
Term
Vitilline (Yolk sac) arteries
¡As the gut tube forms the yolk sac starts to disappear
¡Parts of vitelline arteries are retained to make arteries that supply the gut
¡These arteries, that supply the gut, are the
§(celiac or vitelline)
§superior mesenteric
§inferior mesenteric |
|
Definition
|
|
Term
¡Celiac artery -supplies the (foregut or midgut or hindgut).
¡Superior mesenteric artery -supplies the (foregut or midgut or hindgut).
¡Inferior mesenteric artery- supplies the (foregut or midgut or hindgut). |
|
Definition
|
|
Term
Veins: the fate of the vitelline and umbilical veins
These veins enter the (sinus venosus or septum transversum), which lies in the (sinus venosus or septum transversum)
. |
|
Definition
| sinus venosus, septum transversum |
|
|
Term
Veins: Fate of the vitelline and umbilical veins
¡The liver grows as a proliferation of gut (endoderm or mesoderm) (the liver buds) into the septum transversum.
¡Vitelline vessels in this region, together with umbilical veins, form the (hepatic sinusoids or hepatocardiac channel) |
|
Definition
endoderm
hepatic sinusoids |
|
|
Term
Fate of the vitelline and umbilical veins
¡After contributing to development of the liver sinusoids, the proximal portions of both umbilical veins degenerate.
¡A connection is formed between the distal left umbilical vein and the right (hepatocardiac channel (IVC) or ductus venosus)
§This connection is called the (ductus venosus or hepatocardiac channel (IVC)). |
|
Definition
hepatocardiac channel (IVC)
ductus venosus |
|
|
Term
Development of the vitelline and umbilical veins
¡Blood now flows from the placenta through the (left or right) umbilical vein, bypasses the liver through the ductus venosus
¡Now blood enters the heart via the inferior vena cava (derived from the right hepatocardiac channel). |
|
Definition
|
|
Term
Cardinal veins
¡At (3 or 4) weeks, the cardinal veins are sufficient to drain blood from the head and body wall.
¡As organs develop, the cardinal system is insufficient
§ separate drainages are established that eventually form the definitive vessels. |
|
Definition
|
|
Term
Cardinal veins
¡A connection forms between the two (anterior or posterior) cardinal veins, called the left brachiocephalic vein.
¡The anterior cardinal veins form the jugular system.
¡The right common cardinal vein forms the (inferior or superior) vena cava. |
|
Definition
|
|
Term
Cardinal veins
¡Anastomoses are made between each of these cardinal vein systems so…
§blood flow shifts from the (left or right) side to the (left or right)
§the (inferior or superior) vena cava forms on the right. |
|
Definition
|
|
Term
Cardinal Veins
¡Most of the posterior cardinal veins degenerate
¡New veins are:
§supracardinals--- drain the (body wall or kidneys or lower extremities)
§subcardinals ---drain the (body wall or kidneys or lower extremities)
§Sacral cardinals ---- drain the (body wall or kidneys or lower extremities) |
|
Definition
body wall
kidneys
lower extremities. |
|
|
Term
Cardinal Veins
¡The (supracardinals or subcardinals or sacrocardinals)
§ form the hemiazygous and azygous system
¡ The (supracardinals or subcardinals or sacrocardinals)
§form the renal and gonadal veins
¡The (supracardinals or subcardinals or sacrocardinals)
§form the iliac veins.
¡On the right, each of these systems contributes a segment to the inferior vena cava. |
|
Definition
supracardinals
subcardinals
sacrocardinals |
|
|
Term
Fetal Circulation
¡Umbilical veins become the (lateral or medial) umbilical ligament
¡Ductus venosus becomes the ligamentum (arteriosum or venosum)
¡Ductus arteriosis closes and becomes the ligamentum (arteriosum or venosum) |
|
Definition
medial
venosum
arteriosum |
|
|
Term
Blood cells Origins
¡The extraembryonic yolk sac (mesoderm or ectoderm) and dorsal aorta are important sites of blood cell formation in the embryo. |
|
Definition
|
|
Term
Hematopoietic stem cells and hematopoiesis
¡Hematopoiesis is the differentiation of blood cells.
¡A hematopoietic stem cell is a cell which can self-renew and generate blood cells. |
|
Definition
|
|
Term
¡Blood cell formation (hematopoiesis) occurs at different sites at different times:
• first in the embryonic yolk sac
•then in the dorsal aorta and placenta
• then in the fetal liver
•last in the bone marrow and spleen just before birth. |
|
Definition
|
|
Term
¡The (yolk sac or dorsal aorta) is the major source of both hematopoietic stem cells and blood cells early in embryogenesis.
¡The (yolk sac or dorsal aorta) is the major source of hematopoietic stem cells for fetal life
§These stem cells migrate to the liver and bone marrow/spleen |
|
Definition
|
|
Term
| The yolk sac mesoderm is the first site of blood formation. |
|
Definition
|
|
Term
The dorsal aorta endothelium gives rise to blood cells
and hematopoietic stem cells |
|
Definition
|
|
Term
Fetal (Liver or Spleen) Hematopoiesis
The stem cells from yolk sac, placenta and dorsal aorta migrate to the liver, where they reside and generate blood cells.
Later, the stem cells migrate to the bone marrow and spleen. |
|
Definition
|
|
Term
¡The lymphatic system develops at week (6 or 7)
¡
¡It makes connections with the venous system
¡
¡The ealy lymphatic capillaries join to form a network of lymphatics |
|
Definition
|
|
Term
¡Six primary lymph sacs
§Become lymph nodes
¡Lymph vessels connect to lymph sacs
¡2 large lymph channels form (right and left thoracic ducts) |
|
Definition
|
|
Term
¡Lymphocytes form from stems cells of yolk sac
¡Lymphoctyes mature in thymus
¡Lymphocytes found in lymph nodes at birth come from the thymus |
|
Definition
|
|
