dr. nia-fisiologi sirkulasi fetus, bayi, dewasa

8/13/2019 Dr. Nia-Fisiologi Sirkulasi Fetus, Bayi, Dewasa

1/21

Fisiologi sirkulasi fetus, bayi,

dewasa

dr. Rohmania Setiarini


2/21

The Heart: Blood Flow

Deoxygenatedblood in frombody

Oxygenatedblood in lungs

Atria Contract Ventricles Contract

Deoxygenatedblood outto lungs

Oxygenatedblood out tobody


3/21


4/21

The Heart: Cardiac Cycle

Right atrium contracts Tricuspid valve opens Blood fills right ventricle

Right ventricle contracts Tricuspid valve closes Pulmonary semilunar valve

opens Blood flows into pulmonary

artery

Left atrium contracts Bicuspid valve opens Blood fills left ventricle

Left ventricle contracts Bicuspid valve closes Aortic semilunar valve opens Blood pushed into aorta

One heartbeat = one cardiac cycleAtria contract and relax

Ventricles contract and relax


5/21

Conducting System of Heart


6/21

Blood Vessels: Arteries and Arterioles

Strongest of theblood vessels

Carry blood awayfrom the heart

Under high pressure Vasoconstriction Vasodilation

Arterioles Small branches of

arteries Aorta

Takes blood from theheart to the body

Coronary arteries Supply blood to heart

muscle


7/21

Blood Vessels: Veins and Venules

Blood under no pressure inveins

Does not move very easily

Skeletal muscle contractionshelp move blood

Sympathetic nervous systemalso influences pressure

Valves prevent backflow

Venules Small vessels formed when

capillaries merge

Superior and inferior venacava

Largest veins

Carry blood into right atrium


8/21

Blood Vessels: Capillaries

Branches of arterioles

Smallest type of blood vessel

Connect arterioles to venules

Only about one cell layer thick

Oxygen and nutrients can pass out of a capillary intoa body cell

Carbon dioxide and other waste products pass out ofa body cell into a capillary


9/21


10/21

Circulation

Pulmonary circuitright atrium right ventricle pulmonary artery

trunk pulmonary arteries lungs pulmonary veins heart (left atrium)

Systemic circuitleft atrium left ventricle aorta arteries

arterioles capillaries venules veins vena cava heart (right atrium)


11/21

Blood Flow Through Heart


12/21

Systemic and PulmonaryCirculation


13/21

FETAL CIRCULATION

By the third month of development, all major bloodvessels are present and functioning.

Fetus must have blood flow to placenta.

Resistance to blood flow is high in lungs.


14/21

UMBILICAL CIRCULATION

Pair of umbilicalarteries carrydeoxygenatedblood & wastesto placenta.

Umbilical veincarriesoxygenatedblood andnutrients fromthe placenta.


15/21

THE PLACENTA

Facilitates gas andnutrient exchange

between maternaland fetal blood. The blood itself does

not mix.


16/21

UMBILICAL VEIN TO PORTAL

CIRCULATION

Some blood from theumbilical vein entersthe portal circulation

allowing the liver toprocess nutrients. The majority of the

blood enters the ductusvenosus, a shunt whichbypasses the liver andputs blood into thehepatic veins.


17/21

FORAMEN OVALE

Blood is shuntedfrom right atrium toleft atrium, skipping

the lungs. More than one-third

of blood takes thisroute.

Is a valve with twoflaps that preventback-flow.


18/21

DUCTUS ARTERIOUSUS

The blood pumpedfrom the right

ventricle enters thepulmonary trunk. Most of this blood is

shunted into theaortic arch throughthe ductusarteriousus.


19/21

WHAT HAPPENS AT BIRTH?

The change from fetal to postnatalcirculation happens very quickly.

Changes are initiated by babys firstbreath.
http://www.medical-illustrator.co.uk/showcase.html


20/21

Foramen ovale Closes shortly after birth,fuses completely in firstyear.

Ductus arteriousus Closes soon after birth,becomes ligamentumarteriousum in about 3

months.Ductus venosus Ligamentum venosum

Umbilical arteries Medial umbilical ligaments

Umbilical vein Ligamentum teres


21/21

PROBLEM WITH PERSISTENCE

OF FETAL CIRCULATION

Patent (open) ductus arteriosus and patentforamen ovale each characterize about 8%of congenital heart defects.

Both cause a mixing of oxygen-rich andoxygen-poor blood; blood reaching tissuesnot fully oxygenated. Can cause cyanosis.

Surgical correction now available, ideallycompleted around age two.

Many of these defects go undetected untilchild is at least school age.

dr. nia-fisiologi sirkulasi fetus, bayi, dewasa

Documents