Human Anatomy MV 1

Question 1

Why is it important that oxygen binds loosely to hemoglobin?

Answer 1

It is important bc it allows hemoglobin to be an ideal transporter. This is bc oxygen must be able to associate and disassociate depending on the oxygen tension. Gases that bind in a too stable way are toxic, such as carbon monoxide.

Question 2

What is the Septum and why is it important?

Answer 2

The septum divides the heart in two sections, the arterial and the venous part. The complete development of the septum is the last morphological step of the fetus. The septum allows for the division between oxygenated and deoxygenated blood.

Question 3

What is the relationship between types of blood vessels and their histology?

Answer 3

As a general rule: the closer the vessel is to the heart the more pressure there is. This means that vessels such as the aorta have more elastic tissue and less smooth muscle than capillaries. Also smooth muscle is higher in capillaries because vasodilation and vasoconstriction is necessary during specific events.

Question 4

How is blood flow out of an injury in respect to its position in the body?

Answer 4

The closer the injury to the heart the more the blood flow out of the injury is homogenous to the systolic and diastolic phases. Ex. Injury to the femoral artery. In contrast when you cut your finger the blood flow is slow and continuous.

Question 5

What is Myocardial infarction?

Answer 5

It is caused by the occlusion of the coronary vessels, the ones that bring nutrient to the muscles of the heart. Most MIs are caused by fat based nutrition, diabetes and smoking. MIs also dependent on genetic predisposition.

Question 6

What is cardiovascular adaptation?

Answer 6

Physiologically are hearts adapt to follow the requirements of the body. Cardiovascular transitory adaptations are those that occur after for example going up a flight of stairs. The heart will adapt to the situation making it easier and then after go back to its original state. Morpho-functional cardiovascular adaptations are those present in for example bikers. Their heart has increases in size due to the rigorous daily exercise.

Question 7

What is the structure of the heart?

Answer 7

The outermost layer is the Epicardium which is a visceral layer part of the serous pericardium. Deeper is the Myocardium which is the cardiac muscle tissue. Within the Myocardium is a layer of fibrous skeleton. The innermost part is the Endocardium which is in contact with blood therefore it is lined by epithelium.

Question 8

Anatomically speaking, where is the heart contained?

Answer 8

It is contained in the mediastinum, which is the central part of the thorax.

Question 9

What is the mediastinum and how is it divided.

Answer 9

The mediastinum is delineated superiorly by the first rib, inferiorly by the diaphragm, posteriorly by the bodies of the vertebrae, anteriorly by the sternum and laterally by the pleura. The imaginary line that planes form the sternal angle to the cavity between T4 and T5 delineated the superior from the inferior mediastinum.

Question 10

What are the three collateral arteries that origin from the aortic arch?

Answer 10

From the left: Left Subclavian artery, Left Common Carotid artery which goes into the neck and then bifurcates, and then Branchiocephalic artery.

Question 11

Describe the path of the aorta?

Answer 11

The aorta arches at level T4 at the same level as the tracheal bifurcation. After the arch is descends with the esophagus on its left. While it descends the esophagus moves forward so the aorta can pass behind. The aorta passes the diaphragm at T12.

Question 12

How does the head circulation drain?

Answer 12

Blood from the Braine drains into the sinuses, in the Confluence of sinuses. The sigmoid sinuses which is posterior then drains into the Interna Jugular vein.

Question 13

Which arteries give blood to the brain?

Answer 13

Internal Carotid artery and Vertebral artery.

Question 14

What is the path of the ICA?

Answer 14

The ICA climbs upward into the neck and enters the skull at the tip fo the Temporal pyramid. Once inside the skull in turns a little upwards and backwards for a few cm before giving off collaterals. The most important one being the Ophthalmic artery.

Question 15

What is the only artery that can be seen from the outside?

Answer 15

Central Retinal artery.

Question 16

What is the path of the vertebral arteries?

Answer 16

They move upward into the neck passing through the holes in each vertebra. After C1 they anastomoses and enter the skull through the great foramen as the Basilar artery.

Question 17

What are the three openings to the right atrium?

Answer 17

The inferior and superior vena cava and the coronary circulation that empties into the coronary sinuses that ultimately empty in the right atrium.

Question 18

What is the thebesian valve?

Answer 18

It is another valve that aids outflow to the right atrium. It is found around the coronary sinus.

Question 19

What is the importance of trabeculae, where are they found and what are the different types?

Answer 19

Trabeculae help prevent the reversion of blood flow after the valves are closed. There are 3 types. Type 1, 2 and 3. They are found for example on the surface of heart ventricles.

Question 20

What are the thicknesses of the LV, RV and interventricular septum?

Answer 20

LV is 8-12 mm and the RV is 3-5 mm. The Interventricular septum is thick like the LV and bulges toward the side of the RV because LV produces higher pressure than RV.

Question 21

How are the valves during systole and diastole?

Answer 21

During systole the atrioventricular valves are closed and the semilunar are open. During diastole the atrioventricular valves are open and the semilunar are closed.

Question 22

How is the blood flow of the RA and LA?

Answer 22

The RA receives blood from the superior and inferior vena cava, the blood then passes the tricuspid valve, makes a u turn and then leaves through the pulmonary valve and ultimately enter the pulmonary trunk. The LA receives blood from the pulmonary veins which then pass through the mitral valve, then make a u turn to pass the aortic valve and then finally enter the aorta.

Question 23

How do the AV valves close?

Answer 23

When they are open the Chordae Tendinae are relaxed. Before the contraction of the ventricle a stimulus make the Chordae tense up. As the pressure in the ventricle increases the pressure itself finishes the closing of the valves.

Question 24

What are cardiac tones?

Answer 24

They are the noise caused by the valves closing. The first tone is the closure of the AV which is tricuspid and bicuspid contemporary. The second tone is the closure of the semilunar valves.

Question 25

Where is the stethoscope initially positioned?

Answer 25

It is initially positioned in the 4-5th intercostal space which is the position of the apex of the heart. Here mitral component is heard better. More upwards on the right side of the sternum you better here the tricuspid valve.

Question 26

How do electrical impulses travel though the heart?

Answer 26

The sinoatrial node located in the right atrium sends an impulse to the AV node which delays the impulse for a short time to ensure all blood has left the atria. Then the impulses pass to the bundle of His. The Bundle Branches carry the impulse to the apex of the heart then the Purkinje fibers carry the impulses upwards and to the ventricular walls.

Question 27

What does an ECG represent ?

Answer 27

P wave is the first wave and it corresponds to the firing of the impulse form the SA node.
The P-Q segment is the time the impulse take to travel from the SA node to the AV node.
The QRS complex marks the firing of the AV node and represents ventricular depolarization. The Q corresponds to the depolarization of the interventricular septum, the R wave is produce by depolarization of the main mass of the ventricles. The S wave represents the last depolarization at the base of the heart.
The S-T segment reflect the plateau in the action potential this is when the ventricles contracts and pump blood.
The T wave represent ventricle repolarization.

Question 28

What happens to the aorta after the arch, what are its names and some collaterals?

Answer 28

After the arch it becomes Thoracic descending aorta. While descending it give off collaterals like Intercostal arteries for the vascularization of the thoracic wall and Bronchial arteries for the lungs.

Question 29

Where is venous blood that comes from the lower body collected?

Answer 29

Inferior Vena Cava

Question 30

What are the two blood circulations in the lungs?

Answer 30

Pulmonary arteries are involved in the so called public circulation, they move deoxygenated blood from the RV to the lungs where gas exchange occurs. On the other hand Bronchial arteries which are collaterals of the Thoracic descending aorta are responsible for the oxygenation of the lungs without gas exchange.

Question 31

Where do the Opthalmic veins drain the blood?

Answer 31

They drain the blood in one of the sinuses of the dura mater which is called cavernous sinus.

Question 32

What are some characteristics of the external carotid artery and what are its most important collaterals?

Answer 32

The ECA does not enter the skull unlike the ICA. The anterior or ventral collaterals are the superior thyroid, lingual and facial artery. Its posterior collaterals are the posterior Auricular and the occipital arteries. Its deep collateral is the ascending pharyngeal. Its two terminal branches are the superior temporal and the internal maxillary. The ECA passes through the parotid gland.

Question 33

What are the different parts of the internal maxillary artery?

Answer 33

1: mandibolare part
2: pterygoid which is in the middle of the infratemporal fossa
3: Pterygopalatine part enters the pterygopalatine fossa.
The first two parts are contained in the infratemporal fossa and the last part is contained in the sphenopalatine fossa.

Question 34

What are the main collaterals of the 3 parts of the internal maxillary artery?

Answer 34

The mandibular part gives origin to the anterior tympanic, middle Meningeal and the inferior alveolar arteries.
The pterygoid part gives origin to the pterygoid, masseteric, buccinator, posterior deep temporal and anterior deep temporal arteries.
The pterygopalatine part gives origin to the infraorbital, sphenopalatine, pharyngeal, posterior superior alveolar, artery of the pterygoid canal and descending palatine arteries.

Question 35

What is the path of the sublclavian artery? What are some collaterals?

Answer 35

It originates from the aortic arch. It goes up into the neck and than passes over and down the first rib while passing in between the anterior and middle scalene muscle. Anatomist bc of its topographical relationship with the scalene muscle distinguish a pre, scalene ( behind) and post scalene part. The fist part gives origin to the vertebral, thyrocervical, costocervical and internal thoracic artery.