Introduction to Cardiovascular System Flashcards

1
Q

Cardiovascular system

A

1st major organ system to function in embryo

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2
Q

All blood vessels begin as what?

A

Condensations of mesodermal mesenchyme (blood islands) during week 3

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3
Q

Blood islands will rise to what?

A

Blood cells
Vessels
Heart

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4
Q

Blood islands that would become the heart form where?

A

In splanchnic mesoderm around future head and neck of embryonic disc (cariogenic region)

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5
Q

When embryonic heart reaches the thorax, it is what?

A

A pair of endothelial tubes in the body’s midline that fuse into a single tube on Day 20

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6
Q

On what day does the heart start pumping?

A

Day 22

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7
Q

Are the earliest heart chambers paired or unpaired?

A

Unpaired

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8
Q

What are the chambers from tail to head?

A

sinus venosus, atrium, ventricle, and bulbs cordis

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9
Q

Sinus Venous– will become…

A
  • Smooth-walled part of R atrium, coronary sinus, and SA node
  • Also contributes to posterior wall of L atrium
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10
Q

Atrium gives rise to?

A

Ridged parts (pectinate muscles of R and L atria

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11
Q

Ventricle

A

Strongest pumping chamber
- gives rise to L ventricle

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12
Q

Bulbus cordis

A

The truncus arteriosus (4a), gives rise to R ventricle, pulmonary trunk, and 1st part of aorta

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13
Q

What shape does the heart take on when the 4 chambers appear?

A

S- shape
- ventricle moves caudally and atrium cranially. Bending occurs due to rapid growth of ventricle and bulbus cordis

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14
Q

What happens as a result of cardiac looping during week 4?

A

The heart folds on itself and assumes its normal position in left part of the Thorax with atria posterior and ventricles located in a more anterior direction

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15
Q

What happens by month 2?

A

The heart is divided into the 4 definitive chambers by formation of midline atrial and ventricular septa and valves
- Develop from regional thickenings of endocardium: endocardial cushions

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16
Q

During fetal development, what are the 3 early vascular systems?

A

Intraembryonic
Vitelline
Placental

17
Q

Intraembryonic system

A

Dorsal aorta supplies blood to embryonic tissues
Cardinal veins return poorly oxygenated blood from body of embryo into heart tube

18
Q

Vitelline System

A

Vitelline vessels supply blood to and drain blood from yolk sac

19
Q

What system contributes to blood supply of gastrointestinal tract?

A

Vitelline system

20
Q

Umbilical/Placental system

A

Paired umbilical arteries deliver deoxygenated blood and fetal waste products to placenta
Well-oxygenated blood and nutrients from placenta are carried to fetal heart tube via an unpaired umbilical vein

21
Q

By when are all the major vessels formed?

A

Month 3 of development

22
Q

What are the differences between fetal and postnatal circulation (O2 and nutrients access)

A

During pregnancy, the placenta provides both O2 and nutrients to fetus
Therefore, fetal circulation is different in that it bypasses lungs and most of the liver

23
Q

Umbilical Vein

A

Provides oxygen
- rich blood from placenta

24
Q

Some highly oxygenated blood is shunted through…

A

Through the liver to IVC via ductus venosus

25
Q

Ductus venosus

A

Drains into IVC where oxygen-rich placental blood mixes with oxygen-poor blood returning to heart from caudal region of fetal body

26
Q

Where do the IVC and SVC drain moderately oxygenated blood into?

A

Right atrium

27
Q

Blood passage to nonfunctioning lungs is limited by what?

A

Foramen ovale and ductus arteriosus

28
Q

Blood from the right atrium passes into the left atrium via what opening?

A

The foramen ovale in the inter-atrial wall

29
Q

From the left atrium, where does the blood continue?

A

To the left ventricle and aorta to supply the body

30
Q

Does blood from the right atrium reach the right ventricle and pulmonary trunk?

A

Some blood only

31
Q

What is the name for the shunt that diverts blood from the pulmonary trunk to the aorta?

A

Ductus arteriosus (since the lungs are nonfunctioning)

32
Q

What happens to the ductus arteriosus?

A

Constricts and closes which persists as ligaments arteriosum

33
Q

Clamping of umbilical cord causes what?

A

Umbilical vein to constrict- persists as ligamentum teres (“round ligament”) that anchors liver to body wall
Ductus venosus to close- persists as ligaments venous on inferior surface of liver
Umbilical arteries to close- persist as medial umbilical ligaments (folds in anterior abdominal wall inferior to navel)

34
Q

What causes the 2 valve flaps of the oval foramen to close? What comes of it?

A

Oxygenated pulmonary blood pours into the left atrium which raises pressure, the structure known as fossa ovalis in the right atrium persists

35
Q

What constitutes to the largest category of birth defects?

A

Heart and vascular abnormalities; present in 1% of live born infants- 30% of heart defects occur in infants with other major malformations

36
Q

Approximately 2% of heart defects are due to what?

A

Environmental agents, which most have multifactorial causes

37
Q

What is the most common congenital heart malformation?

A

Ventricular Septal Defects (VSDs)
- Occur in isolation in 12/10,000 births (80% concern muscular portion of septum and resolve as child grows)

38
Q

What occurs when bulbs cordis does not divide properly?

A

Transposition of the great vessels
- As a result, aorta originates in the right ventricle and the pulmonary trunk from the left ventricle

39
Q

What has 4 cardiovascular alterations?

A
  1. Pulmonary infundibulum stenosis
  2. Large IV septal defect
  3. An overriding aorta arising directly above the septal defect
  4. Right ventricular wall hypertrophy due to right side pressure