Download ductus venosus

Reveiew on Heart, azygos, abdominal muscles
o Heart Anatomy
 It is enclosed in a double-walled sac called the pericardium consisting of
2 layers:
 The outermost fibrous pericardium
 The inner serous pericardium, which in turn is made up of 2
layers:
o The parietal serious pericardium, which is fused to and
inseparable from the fibrous pericardium.
o The visceral pericardium, which is synonymous with the
epicardium
 The outer wall of the human heart is composed of three layers:
 The outer layer is called the epicardium (or visceral pericardium
since it is also the visceral layer of the pericardium).
 The middle layer is called the myocardium and is composed of
cardiac muscle
 The inner layer is called the endocardium and is in contact with
the blood that the heart pumps. Also, it merges with the inner
lining (endothelium) of blood vessels and covers heart valves.
 The human heart has four chambers, two superior atria and two
inferior ventricles. The atria are the receiving chambers and the
ventricles are the discharging chambers.
 The pathways of blood through the human heart are part of the
pulmonary and systemic circuits. These pathways include the
tricuspid valve, the biscuspid valve (or called the mitral valve), the
aortic valve, and the pulmonary valve.
o The tricuspid and bicuspid valves are classified as the
atrioventricular (AV) valves because they are found
between the atria and ventricles. These valves are attached
to the chordae tendinae (literally the heartstrings), which
anchors the valves to the papillary muscles of the heart.
o The pulmonary semilunar valve separates the right
ventricle from the pulmonary trunk/artery while the aortic
semilunar valve separates the left ventricle from the aorta
respectively.
o A good mnemonic to remember is LAB RAT = Left Atrium,
Bicuspid; Right Atrium, Tricuspid OR You Gotta TRY before
you BUY (Tricuspid comes before Bicuspid in Blood Flow
Through the Heart)
 Externally, the boundaries of the four chambers are marked by
two grooves. The coronary sulcus divides the atria and the
ventricles and the anterior and posterior interventricular sulci
separate the two ventricles.

The interatrioventricular septum separates the left atrium and
ventricle from the right atrium and ventricle, dividing the heart
into two functionally separate and anatomically distinct units.
 Right atrium:
o Right Auricle: Functions to increase capacity of the atria.
o Pectinate muscles: rough muscular ridges of the anterior
wall of the right atrium
o Crista terminalis: vertical ridge of muscle of the lateral
side of the wall. This is an important site where veins enter
the right atrium
o Fossa ovalis
 Right ventricle:
o Trabeculae carneae: irregular muscular ridges
o Papillary muscles: conical muscular projections from the
walls into the ventricular cavity
o Chordae tendinae: strong bands that connect to the cusps
of the tricuspid valve
 Left atrium:
o Left Auricle
o Mostly the atrial wall is smooth, with pectinate muscles
lining the auricle only; however, the wall is slightly thicker
than the right atrium
 Left ventricle:
o Forms the apex of the heart
o Walls are 2 to 3 times thicker than the right ventricular
walls
o Trabeculae carneae: more numerous than in the right
ventricle
o Papillary muscles
o Chordae tendinae
o Heart Valve Anatomy
 Atrioventricular Valves:
 Tricuspid has 3 cusps, while the Bicuspid has 2 cusps
 Semilunar Valves:
 Both have 3 cusps
 No tendinous cords to support them
 Smaller in area than AV valves
 Superior to each semilunar cusp, the walls
o Location of Nodes of the Cardiac Electrical Conduction System
 Sinoatrial (SA) Node in superior lateral, anterior surface of the right
atrium, close to the junction of the SVC
 Atrioventricular (AV) Node inferior, posterior wall of the right atrium
close to the interatrial septum andnear the opening of the coronary sinus
 AV bundle (aka Bundle of His) located in the interventricular septum
between the atria and the ventricles
 Bundle branches found in the interventricular septum
 Purkinje fibers ascend from the apex superiorly in the walls of the
ventricles
o Describe/Draw out the blood circulation through the heart.
 Superior/Inferior Vena cava → Right atrium → Right atrioventricular
valve → Right ventricle → Pulmonary valve → Pulmonary trunk →
Pulmonary arteries→ Pulmonary capillaries → Pulmonary veins → Left
atrium → Left atrioventricular valve → Left ventricle Aortic valve →
Ascending aorta
****extra information which won’t be on the exam****
o Where would you place a stethoscope to do auscultation of the cardiac valves?
 Aortic Valve = Right 2nd Intercostal space (@Sternal margin)
 Pulmonary Valve = Left 2nd Intercostal space (@Sternal margin)
 Left Atrioventricular valve=5th Intercostal space or cardiac apex (@Mid
clavicular line)
 Right Atrioventricular valve = Left 5th Intercostal space (@Sternal
margin)
 Fetal Circulatory Pathway (Gilroy pp. 94, Moore, pg. 94-95 Table 7.6)
o Helpful website: www.indiana.edu/~anat550/cvanim/fetcirc/fetcirc.html
o Oxygentated blood comes to the fetus through the placenta. This leads it ti
the umbilical vein and umbilical cord(maternal and fetal blood are
separated in the placenta by a layer of endocardium-they do not mix!!!).
o Half of this blood bypasses the liver via the ductus venosus and enters
the Inferior Vena Cava. Other half enters the portal vein to supply the liver
with O2 & nutrients.
o Oxygenated blood from Inferior Vena Cava and Deoxygenated blood from
Superior Vena Cava both dump into the right atrium
o Mixture of deoxygenated and oxygenated blood is shunted to the left
atrium via the foramen ovale (mostly bypassing the right ventricle)
o What does not make it to the left atrium, goes into the right ventricle and
into the pulmonary trunk
o From the pulmonary trunk, some of the partially oxygenated blood is
supplied to the fetal lungs, the remainder is shunted into the aorta via the
ductus arteriosus.
o Blood travels down descending aorta into the common iliac aa. into the
internal iliac aa. and then into the paired umbilical aa. and finally back to
the placenta.
Derivatives of Fetal Circulatory Structures
Fetal Structure
Adult remant
Ductus arteriosus
Ligamentum arteriosum
Foramen ovale
Fossa ovalis
Ductus venosus
Ligamentum venosum
Round Ligament of the Liver (Ligamentum Teres)
Umbilical vein
Umbilical arteries
Medial umbilical ligaments

blood traveling from fetus to placenta is an artery while that from placenta to fetus
is a vein
1. At the beginning of the fetal cirulatiory system, what type of blood comes from the placenta
and is transported through which vein into the body of the fetus? What does this fetal vein
become as the adult remnant?
o Oxygenated blood from the placenta is transported through the Umbilical vein into
the body of the fetus.
o Umbilical vein becomes ligamentum teres hepatis (round ligament of the liver).
2.
The oxygenated blood then bypasses the liver by passing which fetal structure? What does
this same fetal structure become as the adult remnant?
o The blood bypasses the liver by traveling through the Ductus venosus
o The ductus venosus becomes ligamentum venosum.
3.
The ductus venosus then provides a direct communication between the umbilical vein and
the inferior vena cava. Knowing this information, the blood from the ductus venosus combines
with (a.) blood in the inferior vena cava which then continues to the heart. Blood travels to
the heart through the (b.) and mixes with deoxygenated blood returning from the superior
vena cava. Blood then enters the right atrium of the heart.
o A. Deoxygenated blood
o B. Inferior vena cava
4.
At this point, since the fetal lungs are not functional most of the blood will bypass the right
ventricle and will be shunted to the (a.) via which fetal structure? What is the adult remnant of
this fetal structure?
o A. Most of the blood bypass the right ventricle and be shunted to the left atrium via
the foramen ovale.
o B. Foramen ovale becomes fossa ovalis
5. Describe/Draw the circulation of fetal blood circulation.
o Umbilical vein → Ductus Venosus → Superior/Inferior Vena Cava → Right
Atrium (a/b) → (a) Foramen Ovale → (e) Left Atrium →Left Ventricle →
Aortic Arch → (f) Descending Aorta → Umbilical aa. OR (b.) Right Ventricle →
Pulmonary a. (c/d) → (c) Ductus Arteriosus → (f) (d) Pulmonary v. → (e)
Martini et al. 2009, Fig. 22.27
6. Some blood will enter the right ventricle from the right atrium and into the pulmonary trunk.
From this point most of this blood will be shunted away from the pulmonary trunk and into the
aorta via which fetal structure? Name the adult remnant of this structure.
o Ductus arteriosus which becomes Ligamentum arteriosum
7. Once the blood circulates through the body it returns to the placenta via which fetal structure
and name its adult remnant. At this point what type of blood is this structure carrying back to
the placenta?
o The blood returns to the placenta via the umbilical arteries, which then later
becomes the medial umbilical ligament as the adult remnant.
o These arteries carry deoxygenated blood back to the placenta.
8. Explain what happens to the formaen ovale and the ductus arteriosus at birth?
o
When the newborn takes its first breath, the lungs then inflate, which then releases
the high resistance in the pulmonary vessels, which then allows the lungs to receive
more blood.
o
When the ductus arteriosus closes, it prevents high pressure aortic blood from being pushed
back into pulmonary circulation. The force of the right ventricle (and volume of blood going
through the lungs) is partly responsible for the increased left atrial pressure.
*****Not on exam******
 Blood Supply to Breast tissue (Gilroy pp. 62)
o Name the three arteries that supply breast tissue and their origins.
 Lateral Thoracic a., Axillary pt. 2
 Medial Mammary a., Internal Thoracic, Subclavian pt. 1
 Lateral Mammary a., Lateral Cutaneous a., Posterior Intercostal aa.,
Thoracic Aorta
Azygos System
1. Discuss venous drainage for the Azygos, hemiazygos, and accessory Hemiazygos veins.
Answer:
a. Azygous: Intercostal spaces 5-12 on the right side
b. Accessory Hemiazygous: Intercostal spaces 5-8 on the left side ***not on
exam***
c. Hemiazygous: Intercostal spaces 9-12 on the left side***not on exam****
2. Trace the venous drainage from the first intercostal space back to the heart
***not on exam***
Answer:
First intercostal space  supreme intercostal vein  brachiocephalic vein 
superior vena cava  right atrium
3. The accessory hemiazygous vein drains which intercostal spaces and dumps into which
two veins?
***not on exam****
Answer:
The accessory hemiazygous vein drains the intercostal spaces 5-8 on the left side
and dumps into the azygous v. and the left superior intercostal vein.
4.
Explain the difference in course of the superior intercostal veins on the right and left
sides.
Answer:
The right superior intercostal vein drains intercostal drains into the azygos
vein. Whereas, the left superior intercostal vein drains into the
brachiocephalic vein
5.
Draw the basic structure of the azygos vein system and label the following: right and left
supreme intercostal veins, right and left superior intercostal veins, azygos vein, hemiazygos vein, and accessory hemi-azygos vein.
Answer:
6.
The azygos vein receives contributions from two structures on the left side of the
vertebral column. What are these two structures and at what level of the vertebral
column does this occur (in relation to specific vertebra)?
Answer:
Accessory hemi-azygos at the level of T8
Hemi-azygos vein at the level of T9
Abdominal Cavity
***not on exam***
 Camper and Scarpa Fascia (Moore pp. 186-191)
In human anatomy, the layers of the abdominal wall are (from superficial to deep):
o Skin
o Subcutaneous tissue
o Camper's fascia - fatty superficial layer
o Scarpa's fascia - deep fibrous layer
o Muscle
o External oblique muscle
o Internal oblique muscle
o Rectus abdominis
o Transverse abdominal muscle
o Fascia transversalis ***not on exam****
o Peritoneum
***not on exam****
***This info is important but for this class just give it one read
through and don’t worry about studying***
o Camper’s fascia: the thick and fatty superficial layer of the anterior abdominal
wall. It is found superficial to Scarpa's fascia. It continues into the scrotum of
males as the Tunica Dartos.
o Scarpa’s fascia: the deep membranous layer of the anterior abdominal wall. It is
found deep to the Camper Fascia and superficial to the External Oblique muscle.
It is loosely connected to the aponeurosis of the External Oblique, but in the
middle line it is more intimately adherent to the linea alba and to the pubic
symphysis, and is prolonged on to the dorsum of the penis, forming the
fundiform ligament; above, it is continuous with the superficial fascia over the
rest of the trunk; below and laterally, it blends with the fascia lata of the thigh a
little below the inguinal ligament; medially and below, it is continued over the
penis and spermatic cord to the scrotum, where it helps to form the dartos.
 ***not on exam****
 ***This info is important but for this class just give it one
read through and don’t worry about studying***
***not on exam****
***This info is in more detail than you will be presented give
it one read through and don’t worry about studying***
***not on exam****
Q. List, from superficial to deep, the layers of the abdominal wall at a point just lateral to the
linea alba and superior to the arcuate line.
o A. Skin, Camper's fascia, Scarpa's fascia, external oblique aponeurosis, internal
oblique aponeurosis, rectus abdominis, rectus sheath/transversus abdominis
aponeurosis, peritoneum
o Q. Scarpa's fascia is continuous with a structure in the pelvic region. What is it, and
where is it located?
o
A: Scarpa's fascia is continuous with the Dartos layer in the scrotal sac