Heart Chambers and Double Circulation

Question 1

Types of circulatory system

Answer 1

Systemic, supply body
Pulmonary, supply lungs
Portal, mode of transport for nutrients, hormones

Question 2

Definition of an artery and vein

Answer 2

Artery, any vessel leaving the heart
Vein, any vessel entering the heart

Completely unrelated to whether the blood is oxygenated or deoxygenated

Question 3

Describe the features of the right atrium

Answer 3

SVC, IVC opening
Coronary sinus opening with rudimentary valves
R auricle wraps around great vessel

Muscle pectinati (only in atrium) with crista terminalis (junction between embryological chamber and proper atrium)

Fossa ovalis separates circulations

Smooth sinus venarum (posterior septal wall)

Tricuspid/AV valve between RA and RV

Question 4

Shape of the right ventricle and left ventricle, superior inferior view with an ultrasound

Why is the muscle on the L thicker than the R

Answer 4

RV, crescent shape
LV, more spherical with 2 indentations for the ant, post papillary muscle

Muscle around LV is thicker as blood needs to be pumped around the body

Question 5

Structure and features of the right ventricle

Answer 5

AV valve attached to chord tendinae, attached to papillary muscles at the base of the ventricle (prevent valve prolapse)

Trabecular carnae (meaty ridge) keeps blood moving, prevent clot formation

Infundibulum, funnels blood up through semilunar valve

Interventricular septum made up of membranous smooth and muscular part (2 embryological origins)

Question 6

Describe a ventricular septal defect

Answer 6

Gap in interventricular septum
Results in mixing of oxygenated and deoxygenated blood

Severe as more oxygenated blood will flow from the LV => RV (increased pressure in L than R), less O2 reaching tissues

Question 7

Describe the structure of the left ventricle and atrium

Answer 7

Left atrium has 4 openings for 2 R and L pulmonary veins

No roughness, developed from different atrial chamber from RA

Mitral/bicuspid between LA, LV

Chordae tendinae (have limited length) held down by papillary muscles

Interventricular septum has membranous and muscular section

L auricle wraps around aorta, has aortic valve

Question 8

What is endocardititis and what can happen?

What is mitral stenosis and how is it treated

Answer 8

Infection of heart, valves get infected and fibrous

Mitral stenosis, calve cusps narrow => reduced output
-Treated with mechanical/pig valves

Question 9

Describe mitral valve prolapse and what can happen?

Answer 9

When papillary muscles cannot pull down chordae tendinae down enough to close mitral valve
Results in ventricular blood => atrium, not efficient

Question 10

How much blood can pass through the foramen ovale in the fetal circulation and why?

Answer 10

80%

O2 rich blood from placenta is allowed to pass from the RA => LA for more efficient blood flow to the body

Question 11

How much blood can pass through the ductus arteriosus in the fetal circulation and why?

Answer 11

19%
Mixture of oxygenated and deoxygenated blood from the pulmonary vein can enter the aorta.
Fetus doesn’t need lungs yet

Question 12

How does the ductus arterioles close

Answer 12

Chemistry of the blood changes after baby is born

Closes DA => more fibrous => ligament arteriosus

Question 13

Describe patent fetal circulation in newborns

Answer 13

Patent foramen ovale, blood flow from LA => RA
Patent ductus arteriosus, O2 blood mixes with deoxygenated blood
-O2 blood enters pulmonary circulation