Cardiac Development

Question 1

Vasculogenesis

Answer 1

Creation of blood vessels

Question 2

Angiogenesis

Answer 2

Remodelling and pruning of vessels into a recognisable circulatory system

Question 3

Fistula

Answer 3

Abnormal connection between organs

Question 4

VEGF

Answer 4

Vascular Endothelial Growth Factor

Question 5

RA

Answer 5

Retinoic Acid

Question 6

Circulation , according to Harvey, is ?

Answer 6

One of the first FUNCTIONAL systems to form in the embryo

Why?

Embryo is too big by 3rd week (d14+) to survive without its own circulatory system

Question 7

What is the most vulnerable time for major heart deformations?

Answer 7

3.5 -6.5 weeks

Question 8

Formation of a tube

Answer 8

As development progresses the two heart tubes from either side come together and fuse to give one cardiac tube. (d21)

•The cardiac tube then needs to loop and be partitioned

Question 9

Cardiac tubes start to loop to form the primitive heart: changing from a straight tube to a complex, 4 chambered heart. What drives this?

Answer 9

Changes in Bine Morphogenetic Protein (BMP) signalling which allows cellular shape change by changing cell adhesion

Question 10

Role of Retinoic acid

Answer 10

Specifies posterior (atrial) region

Question 11

Function of Looping

Answer 11

Responsible for forming main chambers: atria and ventricles

Question 12

What process is responsible for the formation of the main heart chambers?

Answer 12

Looping

Question 13

When does looping begin?

Answer 13

After initiation of rhythmic heart contractions and blood flow

Question 14

What helps with looping ?

Answer 14

Pressure

Question 15

The division of the heart occurs via which 3 mechanisms?

Answer 15

• Endocardial cushions
• Single outgrowth (septum primum and secundum)
• Expansion of surrounding areas

Question 16

Cells in the atrioventricular canal derive from?

Answer 16

Endocardium

Question 17

Cells in the outflow tract derive from?

Answer 17

Neural crest cells

Question 18

Valves form from?

Answer 18

Endocardium fusion

Mesenchymal tissue becomes fibrous, whilst the softer tissue below “erodes”, leaving valves and muscular cords.

Question 19

What are Septa?

Answer 19

Septa are formed at boundaries to subdivide the heart into chambers. (d27-37)

Question 20

Which disease has the following characteristics:

• Autosomal dominant mutation in Tbx5
• Associated with various cardiovascular defects (75%)
• Atrial septal defects,
• Ventricular septal defects
• Cardiac conduction: brachycardia or fibrillation
• Limb (thumb) defects
• Shoulder girdle defects
• Extent depends on mutation point

Answer 20

Holt- Oram syndrome

Question 21

Division between the atria is not complete until after birth.

True or false

Answer 21

True

Question 22

Two septa form in the atria:

Answer 22

Septum Primum

Septum Secundum

Question 23

CEll death creates a hole called?

Answer 23

Foramen ovale

Question 24

Function of Foramen ovale

Answer 24

Allows blood flow between the RA and LA

Question 25

Consequences of partitioning failure

Answer 25

Atrial septal defects Ventricular septal defects

Question 26

Primum and secundum septa form via

Answer 26

Outgrowth A ridge at the back of the atria grows out to occlude the space Tissue grows from the back wall to split the chamber completely

Question 27

Septal divisions are created via ?

Answer 27

- Outgrowth - Expansion: of surrounding tissue Surrounding tissue expanding beyond a fixed point will lengthen a septum. The space will never be completely occluded this way

Question 28

Congenital heart defects

Answer 28

Stenosis: •Eg Narrowing ``` Septal defects (6.4/10,000) •“holes” ``` Valve defects: • Stiffening of valves/fusion •Lack of valve Vessel defect: •In the wrong place (transposition)

Question 29

What is the Tetralogy of a fallout?

Answer 29

1. Pulmonary valve stenosis 2. A large VSD (ventricular septal defect) 3. An overriding aorta. ie aorta is between L and R ventricles, directly over the VSD. Oxygen-poor blood from the RV flows into the aorta instead of the pulmonary artery. 4. Right ventricular hypertrophy

Question 30

Ectopia Cardis

Answer 30

Heart outside of body

Question 31

Heart progenitor cells move in the primitive streak to form?

Answer 31

Primary heart field- above the embryo

Question 32

This structure: Forms centrally to pharynx Contributes to cardiac lengthening Right ventricle and outflow tracts Forms the dorsal mesocardium, anchoring the cardiac tube to the wall

Answer 32

Secondary heart field

Question 33

Secondary heart field forms?

Answer 33

Forms the dorsal mesocardium, anchoring the cardiac tube to the wall

Question 34

Explain formation of heart tube

Answer 34

1. CElls in Primary heart field form a horseshoe-shaped tube and induce myoblasts in the surrounding mesoderm, giving two of the heart’s layers ENDODERM MYOCARDIUM 2. Folding of the embryo brings the tubes together

Question 35

Function of Tbx 5

Answer 35

Express division for Septa.

Question 36

What happens to the High concentration at the bottom of mesoderm of Retinoic acid?

Answer 36

Diminishes as it moves up

Question 37

Low concentration of Retinoic acid at the top in the mesoderm specialises

Answer 37

Ventricles

Question 38

The mesoderm will initially produce its win Retinoic acid, what happens next?

Answer 38

Cardiac tube will produce its own Retinoic acid to help patterning

Question 39

Endocardial cushion

Answer 39

Outgrowth into cardiac tube - valves are formed this way

Question 40

Cardiac tube is made of three regions:

Answer 40

Truncus arteriosus - top Bolbus cordis Sinus venosus with atria, vitelline veins

Question 41

Which gene okay a role in position when Selta are formed?

Answer 41

Tbx 5 genes

Question 42

Septum primum and secudnum form in what way?

Answer 42

Outgrowth A ridge at the back of the atria grows out to occlude the space

Question 43

Creation of septa can occur in two ways:

Answer 43

Outgrowth Expansion of surrounding tissue

Question 44

Creation of septa (septal division)via outgrowth

Answer 44

Tissue grows from the back wall to split the chamber completely

Question 45

Creation of septa (septal division) via expansion of surrounding tissue

Answer 45

Surrounding tissue expanding beyond a fixed point will lengthen. The space will never be completely occluded this way

Question 46

Name the process: Tissue grows from the back wall to split the chamber completely

Answer 46

Outgrowth to create septa

Question 47

Name the process: Surrounding tissue expanding beyond a fixed point will lengthen. The space will never be completely occluded this way

Answer 47

Expansion of surrounding tissue to create septa

Question 48

Congenital heart defects statistics

Answer 48

1% infants have heart/vascular defects 30% associated with other abnormalities