HTHSCI 1H06 B Lecture Notes - Lecture 2: Sinoatrial Node, Great Vessels, Medulla Oblongata
22 Jun 2018
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CARDIAC DEVELOPMENT
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Postnatal Adult circulatory system
•
pulmonary :
-right side left atrium →left ventricle -7 aorta -7 descending aorta →capillaries of
-oxygenation body tissues -7 venous system
-removal ofcoz
•
systemic circulation :
left side venacavae →right atrium -7 right ventricle →pulmonary trunk
delivery system →capillary beds of lungs -7 pulmonary veins -7 left atrium
transport otwastekoztheat )
*
Arteries carry blood away from the heart
Fetus
•
Fetus circulation needs to be different because of the circumstances
gas exchange at placenta
nonfunctioning lungs
>osthatal circulation VFetal Circulation
key Features Fetal Postnatal
Site of oxygen exchange Placenta Lungs
Circulations Parallel series
Open circuit Closed circuits pressure is higher on the
Separation of Rtlsides right because pulmonary
Shunts and bypasses open closed vasculature is closed .
' .the
Oxygenation otbloodlnheart Rtl :deoxytoxy kdeoxy Lioxy right Ventricle hastopump
Pressure Higheronrightside Higher on left side against higher resistance Placenta
:isaweuvasculated ,
-low resistance vessel which
Bypasses lshuntsinthefetal Circulation .reduces systemic pressure on
•
Bypasses and openings allow for communication the left
(oxygenated )→
oxygenation →umbilical →umbilical →ductus →inferior vena cava
#
right →foramen Ovale -3
left →left →In aorta →taorta →body
at placenta vein cord venoms
sulpemriooxrppeennaactardatnatnum
pulmonary veins atrium ventricle tissues
remaining blood from →right →pulmonary →ductus →taorta →body →uamrhfielpjegl →placenta for umbilical
superior vena cava and ventricle trunk arteriosus tissues oxygenation arteries
foramen Ovale
•
Ductusvenosusiisthebypasstothe
liver
liver is nonfunctioning as maternal circulation is covering it ,so fetal organs can focus on postnatal development
50% of blood goes to liver for development ,501 .to inferior vena cava
•
Foramen Ovale formation occurs intheinteratrial septum
itallowsoxegenateablooafromplacentatogettofetaltissuesthatheeditthemost as quickly as possible 1heart and brain )
•
Ductusarteriosusiisthebypasstothelungs
lungs are nonfunctioning :.maternal circulation covers it ,however 10% stillgoestothe lungs
Key Changes at Birth
'With loss of placenta ,systemic pressure on
the left side is driven up
2With babies first breath ,pulmonary vasculature
opens up so right side doesnt have to pump as
hard :pressure drops which enables closure
of foramen Ovale
÷
exchange and pressure differential
Postnatal Remnants
etal Postnatal
Foramen ovale Fossa oval is
Dnitusarteriosus Ligament um arteriosum
puctus venous ligament um venosum
Umbilical arteries Medial umbilical arteries
Umbilical vein Ligament umteres
Closure in the Postnatal Circulation
•
Fossa Ovalis
Was foramen ovale . appearing as adepression in the inter arterial septum
Opening closes immediately after birth
when pressure goes up on the left side there is closure of the valve 1takes ayear )
•
ligament um artenosum
was ductus arteriosus
Closes 24-48 hafter birth ,resulting from an increase in Oxygen tension or loss of PGEI causing contraction
•Ligament um venosum
was auctus venoms
it will shut down and become aligament in 3months ,which involves proliferation of tissue -matrix proteins helping it shrink down to become a
CT strand Sacculations
right atrium
•SA node
Ligament um
1
Sinus venous →
coronary sinus
Was umbilical
vein 2Atrium →right atrium
can constrict and collapse and get filled with connective tissue ,becoming remnants ,
3Ventricle →left ventricle
•Medial umbilical ligaments 4
Bulbns cordis →right ventricle
aorta
,
Was umbilical arteries
5Truhcus arteriosus →pulmonary trunk
•
Bypasses close quickly at birth but take months to completely seal
Tubular Heart
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Starts with 2endocardial strands at 2 Weeks ,fusing at 4weeks
•
Tube develops sauulatiohs ,forming 5regions
•Tube elongates until it cant anymore ,then folds in on itself
•
Regions give rise to different parts of the heart
Document Summary
Adult circulatory system pulmonary : right side oxygenation removal ofcoz systemic circulation : left side delivery system left atrium left ventricle -7 aorta. 7 descending aorta capillaries of body tissues -7 venous system venacavae. 7 right ventricle pulmonary trunk capillary beds of lungs -7 pulmonary veins. Fetus circulation needs to be different because of the circumstances gas exchange at placenta nonfunctioning lungs. Bypasses and openings allow for communication oxygenation at placenta umbilical umbilical vein cord ductus venoms ( oxygenated foramen ovale inferior sulpemriooxrppeennaactardatnatnum right vena cava pulmonary veins isaweuvasculated. Placenta resistance vessel which low reduces systemic pressure on the left. In aorta ventricle taorta body tissues remaining blood superior vena from cava and right ventricle pulmonary ductus trunk arteriosus uamrhfielpjegl. Ovale itallowsoxegenateablooafromplacentatogettofetaltissuesthatheeditthemost as quickly as possible 1 heart and brain ) lungs are nonfunctioning : maternal circulation covers it however. 10% stillgoestothe lungs foramen ovale liver liver is nonfunctioning as maternal circulation.
