lesson 12

Question 1

During the early phases of development, the embryo is nourished through ___ ___ _ ___ secreted by the uterine glands into the uterine cavity.

Answer 1

diffusion from the fluid ;

Question 2

However, as the size and complexity of the
embryo increases it soon needs a ____ ____

Answer 2

it soon needs a circulatory
system

Question 3

The __ __ including the heart, arteries, veins, and blood begins to
develop as early as the __ ___ to meet the embryo’s needs.

Answer 3

The circulatory system ; third week of
gestation

Question 4

the first functional organ system.

Answer 4

circulatory system

Question 5

The formation of blood cells, called _____ ,
occurs in ____ overlapping periods.

Answer 5

hematopoiesis: three overlapping periods

Question 6

First period is called in formation of blood cells?

Answer 6

mesoblastic period

Question 7

Mesoblastic period occurs where?

Answer 7

The Yolk sac

Question 8

Second period is called ____ in blood formation and these 2 organs in this period are the major blood-forming organs. What are those?

Answer 8

hepato-lienal period; liver and the spleen

Question 9

Third period is called ____ in blood formation and the major organ in blood formation here is what?

Answer 9

medullary period; bone marrow

Question 10

In the mesoblastic period, the first blood cells appear in the ___ ___ ___ ___ very early in development.

Answer 10

visceral
mesoderm of the yolk-sac wall

Question 11

At first in mesoblastic period, __ __ are formed, these are spaces in the mesoderm occupied
with clusters of haemangioblasts.

Answer 11

blood islands

Question 12

In the mesoblastic period, Outer cells
differentiate
into ____, forming endothelial cells,
and the inner cells into primitive __ __

Answer 12

angioblasts; primitive blood cells

Question 13

In the mesoblastic period, Blood islands are spaces in the mesoderm occupied by clusters of _____?

Answer 13

Haemangioblasts

Question 14

The blood islands coalesce (come together) and the
____ ____ form ___ establishing
the first vessels.

Answer 14

endothelial cells; tubes

Question 15

In the mesoblastic period, what is established when coalesce of blood islands happen along with endothelial cells creating tubes?

Answer 15

The first vessels

Question 16

vasculogenesis is the process of spontaneous ____ ____ formation.

Answer 16

blood
vessel formation

Question 17

This process of spontaneous blood
vessel formation is referred to as

Answer 17

vasculogenesis

Question 18

Vessels form new vessels by sprouting
a process referred to as

Answer 18

angiogenesis

Question 19

In mesoblastic period, The first blood cells to be formed are ?

Answer 19

primitive nucleated erythrocytes

Question 20

In mesoblastic period, Primitive _____ evolves within a few days into ____ ____ resulting in erythrocytes without nuclei.

Answer 20

Primitive erythropoiesis; mature erythropoiesis

Question 21

Erythrocytes without nuclei is made or created when primitive erythropoiesis is evolved into ____ ____

Answer 21

mature erythropoiesis

Question 22

In hepatolineal period, this specific period in blood formation starts at a crown rump length of __ mm in cattle

Answer 22

8 mm

Question 23

In the liver, in hepato lineal period, these two are seen.

Answer 23

erythropoietic stem cells as well as megakaryocytes

Question 24

In the ___, erythropoietic stem cells and megakaryocytes can be seen.
By __ mm, neutrophils are also formed.

Answer 24

liver; 12 mm

Question 24

neutrophils are seen to be formed in what period?

Answer 24

hepato-lineal period

Question 24

In hepato-lineal period, the ___ becomes the most prominent hematopoietic organ in cattle embryos, up to the 5th month of pregnancy.

Answer 24

liver

Question 24

In hepato-lineal period, what month does the liver’s blood forming activity declines and at birth it has ceased?

Answer 24

6 month

Question 24

The liver is the most prominent hematopoietic organ in what animal embryo? And in up to how many months in pregnancy does this occur?

Answer 24

cattle embryos, 5th month of pregnancy/gestation

Question 25

In hepato-lineal period, this organ is active in hematopoiesis from the third to ___ month of cattle pregnancy.

Answer 25

spleen; seventh (7th)

Question 26

During the sixth month, in hepato-lineal period, the liver’s blood forming activity _____ and at birth what will happens?

Answer 26

declines, ceased (stop)

Question 27

In the medullary period, __ __ begins its hematopoietic activity at a crown-rump length of about __cm during the 4th month of pregnancy in cattle.

Answer 27

bone marrow; 18 cm

Question 27

In the heart, it develops from the horseshoe shaped ___ ___ after embryonic folding.

Answer 27

cardiac tube

Question 28

Moreover, within what cavity of the embryonic disc did the cardiac tube got repositioned?

Answer 28

within the pericardial cavity

Question 28

Embryonic heart beats begin at: Day 22 of pregnancy in the -- Day 23 in the -- and -- Day 24 in the ---

Answer 28

pig; dog & cattle; horse

Question 29

In loop formation, the cardiac tube will become this type of shape, with the loop of pointing what way?

Answer 29

U-shaped; pointing ventrally

Question 29

The cardiac tube undergoes first a __ ___and then an internal division.

Answer 29

Loop formation

Question 30

In the developing heart, the sinus venosus and atrium are initially not enclosed within the _________ but gradually become enveloped by it.

Answer 30

pericardium

Question 31

The curved portion of the _________ develops into the future left ventricle.

Answer 31

ventricle

Question 32

The curved portion of the _________ develops into the future right ventricle.

Answer 32

bulbus cordis

Question 33

What will the curved portion of the bulbus cordis eventually develop into?

Answer 33

right ventricle

Question 33

Later, during loop formation, the atrium becomes positioned _________ to the ventricle.

Answer 33

dorsal

Question 34

Identify the structure that sets the rhythm for the developing heart's beat

Answer 34

sinus venosus

Question 35

In the heart chamber, there are steps in formation of heart chamber. The first two are:

Answer 35

1. Incorporation of the sinus venosus into the atrium 2. Division of the atrioventricular channel

Question 36

In the heart chamber, there are steps in formation of heart chamber. The third step is:

Answer 36

Division of the atrium

Question 37

In the heart chamber, there are steps in formation of heart chamber. The 4th step is:

Answer 37

Division of the ventricle and the bulbus cordis

Question 38

In the heart chamber, there are steps in formation of heart chamber. The 5th step is:

Answer 38

Division of the conus cordis and truncus arteriosus.

Question 39

Step 3: Division of the Atrium Identify the structure that grows to divide the atrium into right and left components.

Answer 39

(Answer: septum primum)

Question 39

What is the role of the endocardial cushions in the formation of heart chambers?

Answer 39

(Answer: They grow and fuse in the midline to form the septum intermedium, dividing the atrioventricular channel into right and left channels.)

Question 40

Step 3: Division of the Atrium Name the structure that develops to the left of the septum primum to assist in atrial division.

Answer 40

(Answer: septum secundum)

Question 41

Step 5: Division of the Conus Cordis and Truncus Arteriosus What structure separates the conus cordis and truncus arteriosus to ensure separate blood flow channels?

Answer 41

(Answer: aorticopulmonary septum)

Question 42

Step 5: Division of the Conus Cordis and Truncus Arteriosus The cushions in the conus cordis fuse with those of the truncus arteriosus to form the _________, which helps in dividing the blood flow into two channels.

Answer 42

(Answer: aorticopulmonary septum)

Question 43

Step 3: Division of the Atrium Before the closure of the ostium primum, programmed cell death forms the _________ in the septum primum.

Answer 43

(Answer: ostium secundum)

Question 43

Step 3: Division of the Atrium The septum primum grows to separate the atrium into right and left components, leaving a small opening called the _________.

Answer 43

(Answer: ostium primum)

Question 44

Step 2: Division of the Atrioventricular Channel In the atrioventricular channel, thickenings called _________ grow until they fuse in the midline, forming the septum intermedium.

Answer 44

(Answer: endocardial cushions)

Question 45

Step 1: Incorporation of the Sinus Venosus into the Atrium The incorporation of the _________ into the atrium is the first step in heart chamber formation. (Answer: sinus venosus)

Answer 45

(Answer: sinus venosus)

Question 46

Step 2: Division of the Atrioventricular Channel At the atrioventricular channel, the inner cardiac wall develops anterior and posterior thickenings, called -___ ___

Answer 46

the endocardial cushions

Question 47

In Arterial system, when the pharyngeal or branchial arches form, each arch receives its ____ and ___

Answer 47

own cranial nerve and its own artery.

Question 48

Aortic Arch Formation and Fate in Mammal: In mammals, the _________ and _________ aortic arches are largely rudimentary, while the fifth arch may remain rudimentary or may not develop at all.

Answer 48

Answer: first, second

Question 48

In the arterial system, When the pharyngeal or branchial arches form, each arch receives its own cranial nerve and its own artery. This results in the formation of _ ______ between the dorsal and ventral aortae on each side.

Answer 48

six arterial arches (aortic arches)

Question 48

The third aortic arch connects the common carotid artery to the _________.

Answer 48

(Answer: internal carotid artery)

Question 49

Only the _________, _________, and _________ aortic arches form components of the developing circulatory system.

Answer 49

(Answer: third, fourth, sixth)

Question 49

Formation of Arteries from the Aortic Arches: The _________ aortic arch largely degenerates, with a small portion forming the ___ ___.

Answer 49

(Answer: first and maxillary artery)

Question 49

The _________ aortic arch becomes the aortic arch on the left, while on the right, it forms the __ ___ artery.

Answer 49

(Answer: fourth; right subclavian artery)

Question 49

Small portions of the _________ aortic arch develop into the ___ and _____ arteries.

Answer 49

(Answer: second; hyoid and stapedial arteries.)

Question 50

: The __ aortic arch regresses on the right, but on the left, it forms the _________.

Answer 50

(Answer: 6th; pulmonary trunk)

Question 51

During fetal development, the pulmonary trunk is connected to the aortic arch via the _________.

Answer 51

(Answer: ductus arteriosus)

Question 52

Post-natal transformation of the ductus arteriosus: After birth, the ductus arteriosus becomes a non-patent structure called the _________.

Answer 52

(Answer: ligamentum arteriosum)

Question 53

BONUS FACT: Before a baby is born, the fetus's blood does not need to go to the lungs to get oxygenated (because all nutrients are provided by the placenta). The ductus arteriosus is a hole that allows the blood to skip the circulation to the lungs

Answer 53

nothing hehe take this sign as a break.

Question 54

Name the three major veins involved in early fetal circulation, carrying blood from the yolk sac, placenta, and body of the embryo.

Answer 54

(Answer: vitelline vein, umbilical veins, cardinal veins)

Question 55

Identify the vein that transports oxygenated blood from the placenta to the embryo.

Answer 55

(Answer: umbilical vein)

Question 55

What vein carries blood from the yolk sac to the developing embryo?

Answer 55

(Answer: vitelline vein)

Question 55

The common cardinal vein, cranial cardinal vein, and caudal cardinal vein are part of the developing _________ system.

Answer 55

(Answer: venous)

Question 56

The _________ vein carries blood from the placenta and provides the embryo with oxygen-rich blood.

Answer 56

(Answer: umbilical)

Question 56

In fetal circulation, blood from the left umbilical vein passes through the _________ venosus to mix with deoxygenated blood in the caudal vena cava.

Answer 56

Answer: ductus

Question 56

Most of the oxygenated blood in the right atrium passes through the _________ ovale into the left atrium.

Answer 56

(Answer: foramen)

Question 56

The _________ ovale permits blood to bypass pulmonary circulation by passing from the right atrium to the left atrium.

Answer 56

Answer: foramen

Question 57

What structure allows blood to bypass the liver and flow directly into the caudal vena cava?

Answer 57

(Answer: ductus venosus)

Question 57

What respiratory center is stimulated to initiate breathing after birth due to increased carbon dioxide tension?

Answer 57

(Answer: medulla oblongata)

Question 57

Name the structure that closes as a result of increased pressure in the left atrium after birth.

Answer 57

(Answer: foramen ovale)

Question 57

Which fetal structure allows relatively oxygenated blood to bypass the lungs and flow from the pulmonary trunk into the aorta?

Answer 57

Answer: ductus arteriosus

Question 57

The _________ arteries carry blood back to the placenta for oxygenation.

Answer 57

(Answer: umbilical)

Question 58

After birth, the closure of which structure prevents blood from the pulmonary trunk from entering the aorta?

Answer 58

(Answer: ductus arteriosus)

Question 59

The first breath expands lung volume and increases blood flow to the lungs, raising pressure in the left atrium and closing the _________ ovale.

Answer 59

(Answer: foramen)

Question 60

The contraction of the _________ venosus and left umbilical vein stops blood flow from the placenta to the newborn.

Answer 60

(Answer: ductus)

Question 61

The _________ arteries contract to stop blood flow to the placenta.

Answer 61

(Answer: umbilical)

Question 62

What structure forms from the cranial portions of the dorsal aortae in the embryo?

Answer 62

(Answer: internal carotid arteries)

Question 63

Which vein carries blood from the cranial portion of the developing embryo?

Answer 63

(Answer: cranial cardinal vein)

Question 64

Which vein is responsible for carrying blood from the caudal portion of the developing embryo

Answer 64

Answer: caudal cardinal vein)

Question 65

The common cardinal vein receives blood from both the _________ and _________ cardinal veins.

Answer 65

(Answer: cranial, caudal)

Question 66

Name the structure that receives oxygenated blood in the ductus venosus and deoxygenated blood from the liver and digestive tract.

Answer 66

(Answer: caudal vena cava)

Question 67

Which chamber of the fetal heart receives mixed oxygenated and deoxygenated blood from the caudal vena cava?

Answer 67

(Answer: right atrium)

Question 68

Which vein brings relatively oxygenated blood to the fetus, bypassing the liver through the ductus venosus?

Answer 68

(Answer: left umbilical vein)

Question 69

The ductus venosus allows blood to bypass the _________ and flow directly to the caudal vena cava.

Answer 69

(Answer: liver)

Question 70

Oxygenated blood from the placenta enters the fetal heart through the _________ vein and flows towards the liver.

Answer 70

(Answer: umbilical)

Question 71

What structure remains as the ligamentum arteriosum after birth, previously allowing blood to bypass the lungs?

Answer 71

(Answer: ductus arteriosus)

Question 72

Upon birth, the increased _________ tension triggers the respiratory center in the medulla oblongata, leading to the newborn’s first breath.

Answer 72

(Answer: carbon dioxide)

Question 73

In the venous system Three major veins can be distinguished: the ______ or vitelline veins carrying blood from the yolk sac the ___ veins carrying blood from the placenta the ____ veins carrying blood from the body of the developing embryo

Answer 73

omphalomesenteric umbilical veins cardinal veins

Question 74

In circulation at birth It terminates the fetal-maternal association through the placenta.

Answer 74

Birth