Development of the Heart Flashcards Preview

Anatomy II: Exam III > Development of the Heart > Flashcards

Flashcards in Development of the Heart Deck (28)
Loading flashcards...
1
Q

when does the CV system begin to appear?

A

mid week 3, heart functions during week 4

2
Q

establishing and patterning of primary heart

A

-progenitor cells (once in epiblasts) migrate thru primitive streak into splanchnic layer of lat plate mesoderm

3
Q

what is the first sign of heart

A

solid horseshoe shape = primary heart field (PHF) (cells will form atria, LV and part of RV)

  • underlying endoderm induces PHF to form cardiac myoblasts
  • blood islands and vessels via vasculogenesis)
  • vasculogenesis: BVs arise from blood islands
  • angiogenesis: BVs sprout from existing vessels
4
Q

when does heart tube formation and positioning occur

A

18-22 days

5
Q

heart tube formation and positioning

A
  • blood islands unite in jorseshoe shaped endotheliam lined tube in cardiogenic region (endocardial tubes)
  • other islands appear at midline to form dorsal aortae
  • lat body folding creates primordial heart tube (lat sides forl ventrally and medially and fuse at midline)
  • cranial caudal folding occurs and repositions developing heart and pericardial cavities
6
Q

what is the hinge for ventral swinging during body folding?

A

oropharyngeal mem

7
Q

position of heart prior to folding

A

rostral to oropharyngeal mem and ventral to pericardial cavity

8
Q

what initially attaches heart tube to dorsal side of pericardial sac

A

dorsal mesocardium

*middle part disappears to form transverse pericardial sinus (present in adults)

9
Q

what gives rise to SA and AV nodes

A

SA canal

10
Q

sinus venoses

A
  • receive blood from 3 paired vv
    1. viteline vv
    2. umbilical vv
    3. common cardinal vv
11
Q

what happens when blood flow in heart shifts R

A

R horn becomes larger than L

-L sinus horn becomes 1. oblique vv of LA 2. coronary sinus

12
Q

what does R sinus horn become incorporated into

A

R atrium (smooth walled part, sinus venarum), resulting in 1. L valve and septum spurium fuse with atrial septum

  1. sup portion of R valve disappears
  2. inf part of R valve becomes valve of IVC and coronary sinus
13
Q

what is the ridge separating smooth and rough wall of RA

A

crista terminalis

14
Q

when does partitioning of heart occus

A

30 days

15
Q

partitioning of heart

A
  • atrial partitioning beginning
  • primary IV foramen undivided
  • outflow tracts undivided
  • prox part bulbus cordis becomes trabeculated = R vent
  • AV canal undivided
16
Q

what are the two ways to form septa

A
  1. endocardial cushions

2. growth/expansion (meeting and fusing)

17
Q

septum primum

A

-extends toward end cushions in AV canal (opening below = ostium primum, foramen primum), it closes perforations in septum primum coalesce to form ostium/foramen secundum

18
Q

septum secundum

A

develops from roof of primordial atrium, to the R of the septum primum, grows inferiorly and develops opening (foramen ovale)

19
Q

formation of fossa ovalis

A

after birth, prressure forces septums primum and secundum together

20
Q

partitioning of outflow tracts

A
  • neural crest cells migrate into truncus arteriosus and bulbus cordis
  • form truncal ridges and bulbar ridges (helps create septum in outflow tract)
  • ridges spiral 180 resulting in spiral aorticopulmonary septum when ridges fuse
21
Q

definitive structure of truncus arteriosus

A

roots and prox portions of aorta and pulm tr

22
Q

definitive structure of conus cordis

A

outflow tracts of ventricles

23
Q

definitive structure of prox segment of bulbus cordis

A

R vent

24
Q

definitive structure of primordial vent

A

L vent

25
Q

definitive structure of primordial atrium

A

L and R auricles and trabeculated portions of aorta

26
Q

definitive structure of R horn of sinus venosus

A

sinus venarum (smooth walled part of RA)

27
Q

definitive structure of L horn of sinus venosus

A

coronary sinus

28
Q

definitive structure of primordial pulm v and brs

A

smooth walled portions of LA