Question

True or false

The heart is located in the mediastrinum slightly to the left of the midline with an anterior left ventricle and posterior right ventricle.

Pacemaker cells form the AV nodes and lack a distinct plateau phase.

The heart consists of two superior ventricles, two AV valves, two inferior atria and two aortic semilunar valves.

Lymph from the lower limbs drains into the right lymphatic duct.

Cardiac cells are joined to one another by intercalated discs that contain gap junctions for depolarization between cells and desmosomes to hold the fibers together when the heart contracts.

The ventricular ejection phase generally correlates with the S-T segment and the T wave on the ECG.

Lymphatic vessels constitute a one-way system that delivers fluid form the blood vessels to the extracellular space

Systole is the contraction portion of the cardiac cycle and diastole is the relaxation portion.

There are typically four pulmonary veins, two draining each lung. They all connect to right atrium.

The sympathetic nervous system increases blood pressure in the short term by increasing cardiac______output¬¬¬¬¬____and___bloodpressure.

The rapid depolarization phase of the contractile cell action potential is due to the opening of voltage-gated potassium ion channels.

The buffy coat is the fraction of an anticoagulated blood sample that contains most of the leukocytes and thrombocytes.

Erythrocytes are biconcave discs with prominent nuclei. The main function of erythrocytes is to transport O2 on the molecule hemoglobin.

The plateau phase in cardiac cell is due to the influx of calcium ions through calcium ion channels
The amount of blood in the ventricles at the end of the ventricular filling phase is the end –systolic volume

The first branch of the aortic arch is the brachiocephalic artery, which divides into the left common carotid artery and the left subclavian artery.

Tissue perfusion to the heart decreases during systole and increases during diastole

Atrial systole is responsible for ejecting most of the blood into ventricles during the ventricular filling phase of the cardiac cycle

.

During heart transplant surgery, an electric shock is sometimes needed to make the donor heart beat properly because the electric shock activates the sympathetic nerve fibers in the ventricles.

People with type AB- (negative) blood are universal recipients because they have no antibodies to A, B or Rh in their blood and can receive red blood cells from a donor of any blood type.

Answer 1

1, True as the heart is seen in mediastinum at its middle and the apex of the heart is formed by the left ventricle and is placed such that it is slightly tilted towards the left side occupying the mediastinum region in between lung lobes.

2. True as the AV node is formed by pacemaker cells and act as the second pacemaker. And the action potential formed by SA and AV node lacks plateau phase like other cardiomyocytes.

3. False as the heart is four-chambered with two atria above and two ventricles below and are separated by two AV valves and also has two semilunar valves of which one is aortic and other is pulmonary valve.

4. False as the popliteal lymphatic nodes seen in the fat reserve of the popliteal fossa which receives lymph from the lower limbs.While the right lymphatic duct is in lymph drainage from right side of the thoracic cavity, arm, neck and head not the lower limb.

5. True as the branched cardiac muscle fibers are connected to each by an intercalated disc which has gap junction which aids in the transfer of action potential and desmosomes help in holding fibers together.