Heart development Flashcards
(105 cards)
1
Q
The heart tube remains attached to the dorsal side of the pericardial cavity by
A
the dorsal
mesocardium
2
Q
• Later, dorsal mesocardium disappears forming————————- which connects both sides of the pericardial cavity
A
the transverse sinus of the pericardium
3
Q
Development of heart & embryonic blood vessels begin —————-
week of gestation.
A
during the 3rd
4
Q
Cardiac progenitor cells lies in
A
These cells lie in the epiblast
5
Q
They migrate through the
A
primitive streak
6
Q
Cells reside within the
A
splanchnic (visceral) layer of lateral plate mesoderm (Cardiogenic field).
7
Q
• The cells lie——-the buccopharyngeal membrane and
neural plate
A
anterior to (rostral)
8
Q
The heart primordium arises predominantly from
A
splanchnic layer of lateral plate
mesoderm
9
Q
The progenitor cells are transformed into
A
the cardiac myoblasts
10
Q
The cardiac myoblasts will later form the
A
myocardium of the heart
11
Q
Vasculogenesis : Blood islands appear in the splanchnic layer of mesoderm
A
to form the blood cells and
blood vessels
12
Q
• The blood islands unite and form a
A
horseshoe-shaped endothelial-lined heart tube
surrounded by myoblasts
13
Q
The horseshoe-shaped cardiogenic cords is s surrounded
A
myoblasts
14
Q
The intraembryonic cavity over the cardiogenic field develops into the
A
pericardial
cavity
15
Q
The horseshoe-shaped cardiogenic cords later develop into
A
2 endothelial –lined
tubes
16
Q
Effect of cephalic and lateral folding After cephalic folding, the cardiogenic area becomes———
buccopharyngeal membrane
A
ventral & caudal
17
Q
• After the lateral folding, the 2 endocardial tubes except at most —— end
A
fuse ———— caudal
18
Q
• Most caudal regions
A
receive the venous drainage (inflow tract).
19
Q
Most cranial region
A
expand and join to the 2 dorsal aortae (outflow
tract)
20
Q
The developing heart bulges more into the
A
pericardial cavity
21
Q
The heart tube remains attached to the dorsal side of the pericardial cavity by
A
the dorsal
mesocardium
22
Q
Later, dorsal mesocardium disappears forming ————————–which connects both sides of the pericardial cavity
A
the transverse sinus of the pericardium
23
Q
Formation of the Primitive 4 Chambered Heart: Single heart tube——
A
elongates.
24
Q
It has 2 ends
A
caudal & cranial ends
25
• Bulges (dilatations) appear forming
4 chambers
26
Sinus venosus (RT & LT horns):
receives blood from veins
27
4 chambers are:
a) Sinus venosus (RT & LT horns) veins.
b) Primitive single atrium.
c) Primitive single ventricle.
d) Bulbus cordis
28
Bulbus cordis: it leads into
2 dorsal aortae.
29
Layers forming wall of heart :
1. Endocardium
2. Myocardium
3. Epicardium
30
Endocardium develops from
the vascular endothelium
31
Myocardium develops from
the myoblasts
32
Epicardium develops from
the mesothelial cells migrating from
| the sinus venosus
33
----------------separates the endocardium from the myocardium
Layer of extracellular matrix ( Cardiac jelly)
34
Causes: continuous elongation
cell shape
different rates of growth in the
of the heart tube
changes
heart tube
35
The cephalic portion of heart tube bends
ventrally, caudally and to right
36
The caudal part
shifts dorso-cranially and to the left
37
When Cardiac looping star to form ?
starts by day 23 & ends by day 28
38
----- shaped then ------shaped tube is formed
u then s
39
Narrow atrioventricular canal connects the primitive
atrium & ventricle
40
Bulboventricular sulcus (between
the bulbus cordis & the ventricle
41
Proximal 1/3 of bulbus cordis give
trabeculated part (Rough part) of right ventricle.
42
middle part of bulbus cordis is called
Conus cordis
43
Middle 1/3 of bulbus cordis (conus cordis ) give
outflow tracts of both ventricles (aortic vestibule &pulmonary infundibulum
44
Distal 1/3 of bulbus cordis is called
truncus arteriosuis
45
Distal 1/3 truncus arteriosus of bulbus cordis give
the roots and the proximal part of the aorta and
| pulmonary trunk.
46
junction between the
| ventricle and bulbous cordis give
primitive interventricular foramen internally and sulcus
| externally
47
Trabeculated Primitive ventricle will give
Primitive left ventricle
48
Trabeculea are formed -------- & ----------- to the primary interventricular
foramen
proximal - distal
49
Trabeculated proximal 1/3 of bulbus
| cordis
Primitive right ventricle
50
The sinus venosus is cavity receiving venous
blood from RT & LT horns, each horn receives
3 main veins:
1. Common cardinal vein (CCV) from body of
the embryo.
2. Umbilical vein (UV) from the placenta.
3. Vitelline vein (VIT) from the yolk sac.
51
Umbilical vein (UV) from the placenta carry --------blood
oxygenated
52
Blood shunt from------ to ------ resulting in
left to right
53
Most of the veins of the Lt Horn are
obliterated
54
The----- horn of sinus venosus becomes very small after obliteration
left
55
The right sinus horn --------after obliteration of left horn
enlarges
56
The sino-atrial opening shifts to the------ and opens
| into the future ------- atrium
right - right
57
The veins of the LT horn obliterates except for -----
part of the --------vein that persists to carry
oxygenated blood from the placenta to the fetus
distal - left umbilical
58
remains of the left sinus
| horn give
1.the oblique vein of left
atrium
2.the coronary sinus.
59
body & right sinus horn
smooth part of Rt. atrium
60
right common cardinal vein give
SVC
61
right vitelline vein
IVC
62
The entrance of sinus venosus is guarded by -----
valves (right & left)
63
valves fuse cranially to form the
septum spurium
64
• Left venous valve + the septum spurium fuse with the
inter-atrial septum
65
Right venous valve the superior part ---------inferior part gives ---------
disappears - inferior part gives the valves of IVC and coronary sinus
66
a line demarcating the smooth and the rough parts of the right atrium.
The crista terminalis
67
body & right sinus horn give
smooth part of the right atrium
68
absorbed parts of pulmonary veins give
smooth posterior part of left atrium
69
common atrium gives -------------------and------------
trabeculated part of the Rt. Atrium
| trabeculated part of the Lt. Atrium( Left auricle )
70
Formation of Cardiac septa
| In… 4 things
* Atrio ventricular canal
* Common atria
* Common ventricle
* Truncus arteriorsus
* Bulbus cordis
71
The septa of the heart are formed at end of the -------- week
the 4th week of development.
72
• There are two main methods of cardiac septa formation :
1. Growth of two active growing opposing masses until they fuse and divide the lumen.
2. Narrow strip of the wall fail to grow while areas on each side of it expand rapidly.
73
Two superior and inferior A-V endocardial cushions appear at
t the borders of the A-V
| canal.
74
Two right and left A-V endocardial cushions appear
on borders of the canal
75
The superior and inferior cushions project into the--------- and ------resulting in a
complete division of the canal into right and left orifices
lumen - fuse
76
a sickle shaped crest grows from the roof of the common
| atrium into the lumen
Formation of septum primum
77
The ----- limbs of this septum extend into the direction of the --------- in the A-V
canal.
2 - endocardial cushions
78
The opening between the lower limbs of the septum primum and the
endocardial cushions.
Ostium primum
79
Before complete closure, perforations appear in the septum primum and the ------------- is form when perforations fuse together.
Ostuim secundum
80
This ensures free blood flow from ----- to ----- primitive atrium
right - left
81
: A new crescent-shaped fold
from above down on the right side of the septum
primum
Septum secundum
82
When the left venous valve and septum spurium
| fuse with the right side of septum secundum, the
free concave edge of the septum secundum begin
| to overlap the ostium secundum.
83
is The opening left by the septum
| secundum
oval foramen
84
the remaining part of
| septum primum after it mostly disappears.
valve of oval foramen
85
------------ is formed by edge of the
| septum secundum
limbus fossa ovalis
86
--------is formed by septum
| primum
floor of fossa ovale
87
After birth…4 things
-Pulmonary circulation starts
-The pressure in the left atrium increases
-It presses the valve of foramen oval against
-the septum secundum leading to closure of
foramen oval.
-fossa ovalis is formed
88
The interventricular (IV)septum has two main parts-----------------------and-----------
muscular & membranous.
89
the medial walls of the expanding ventricles are apposed, merge and , this is the formation of ---------------
the muscular IV septum
90
The space between the free rim of the muscular ventricular septum
and the fused endocardial cushions.
• Interventricular foramen
91
Develops from the fusion between:
..inferior endocardial cushion
..conus septum.
..muscular IV septum
Membranous part of IV septum
92
Two opposing ridges appear in the --------------
| Rt. Superior truncus swelling and Lt. inferior truncus swellings.
truncus arteriosus
93
on right dorsal and left ventral walls. Grow towards each other distally and fuse
with truncus septum
Neural crest cells migrate into truncal and conal swellings
• The swelling merge, fuse, twist around each other spirally.
Two swellings appear in the conus cordis
94
Division of the Truncus arteriosus results in
An aortic and pulmonary channels are formed.
95
Division of the conus results in
anterolateral outflow tract of right ventricle
(Infundibulum of pulmonary trunk)
postero-medial outflow tract of left ventricle (Aortic
Vestibule).
96
Fusion of the endocardial cushions forms the ----------
Atrio-ventricular Valves
97
•in av valve formation Each A-V orifice is surrounded by
local mesenchymal proliferations
98
• Blood stream thins & hollows out that from ------
| But remain attached to the ventricular wall by
their ventricular surface-muscular cords
99
The muscular tissue in the cords degenerates and is replaced-----------They are connected by the trabeculae in the wall of the ventricle------------- by
means of
dense connective tissue- papillary muscles-chordae tendinae
100
bicuspid (mitral) valve have------leaflet
2
101
the tricuspid valve has------- leaflets.
3
102
The ------- appear as small tubercles of mesenchyme at the root of ---------------------------------
semilunar valves-ascending aorta & pulmonary trunk.
103
• The ------ surface is hollowed to form the valves (cusps).
upper
104
• Each valve (cusp) is formed of layer of -------- covered on both
surfaces by --------------------
connective tissue-endocardium (endothelial cells).
105
Smooth part of ventricles comes from
Middle 1/3 of bulbus cords
