Cardiovascular System: Blood Vessels

The three layers of the artery include the intima, media, and adeventia. Intima is the inner most layer that comprise the artery wall. It is a thin wall lines that lines the artery wall with endothelial cells successfully separating blood flow from other layers of the wall of artery

The media is the middle and the thickest of the three walls (Wright, 1993). Media contain strength mechanism like smooth muscles, elastin, and collagen.

The last layer, Adventia is the outermost layer of the artery wall that mostly contains collagen. Adventia provides form and strength of the artery wall.

How do arterial walls differ from venous walls?

There is great difference between arterial wall and the venous wall. Artery usually takes oxygenated blood to various parts of the body while venous take blood back to the heart. Therefore, arteries have to carry blood with high resistance due to heart pumping system. To stand this resistance, arterial walls are thicker while the venous wall is thinner. Venous wall contain valves that prevent push blood back to the heart.

What is the function of valves in the peripheral veins?

Peripheral veins usually take blood from the peripheral parts the body back to the heart. The blood going back to the heart is not pumped and therefore flows back to the heart freely (Wright, 1993). Peripheral veins usually contain vales that prevent the blood from flowing back. Valves are designed to help blood go in one direction against gravity up towards the heart.

Why are arteries deeper than veins in the body?

Arteries appear deeper in the body while veins appear superficially. Arteries work under intense pressure taking blood to organs from the heart. This means that they have to be deeper to withstand the high pressure and be able to reach the vital organs while veins operate under low pressure with no rush return path that can be put superficially (Wright, 1993). Therefore it appears arteries lies deeper in the body to protect them and help them contain high pressure.

Activity 2: Identifying the Major Arteries and Veins on a Fetal Pig

Name the major artery and vein that deliver and drain blood to and from the head.

Carotid arteries supply blood to the head and neck. Blood from the head is taken back to the heart by internal and external jugular vein, subclavian vein, brachiocephalic vein and finally into the superior vena cava vein that enters into the heart (Wright, 1993).

Name the blood vessels that deliver and drain blood to and from the heart.

Major arteries leaving the heart including aorta, pulmonary trunk, arterial duct, and pulmonary arteries

Major veins entering the heart including anterior vena cava and posterior venacava

Describe the branching of the aorta as it leaves the heart. Where does it go?

As the aorta takes blood away from the heart, it braches into the following arteries taking blood to different parts of the body (Wright, 1993):

Carotid arteries taking blood to neck and head Coronary arteries supplying heart with the blood Hepatic artery taking blood to the liver Mesenteric artery taking blood to the intestines Renal arteries taking blood to the kidneys Femoral arteries taking blood to the legs Name the major arteries and veins that deliver and drain blood to and from the upper appendages.

Left subclavian artery supplies blood to the shoulder area. Axillary artery supplies blood to the upper arm while brachial artery supply upper arm region below the elbow. Radial artery supply lateral side of forearm, ulnar artery supply medial side of the forearm, and palmar arches supplies hand and fingers (Wright, 1993) Palmar venous arches drain hands and fingers while cephalic veins empty into axillary vein. Medin cubital vein connects cephalic and basic vein at the elbow. Radial veins drain lateral side of forearm and ulnar vein drains medial side of the forearm. Axillary vein drains the axillary areas and empties into axillary vein. On the toher hand, subclavian vein drains blood from the shoulder.

Name the major arteries and veins that deliver and drain blood to and from the lower appendages.

Femoral arteries take blood to the legs. This branches to right and left iliac arteries which supplies pelvic organs. Femoral artery supplies thighs, popliteal artery supplies knee and tibial arteries supplies area below knees (Wright, 1993). Plantar arches supplies foot and toes. Plantar venous arches veins drain feet and toes while anterior and posterior tibial veins returns to the heart blood from below the knee. Femoral veins drain the thigh. External ilica vein drain the groin, internal iliac vein drain pelvic organs. External and Internal iliac vein forms the inferior vena cava that enters the heart

What is the large vein that enters the liver? Where do its branches originate from?

The large vein that enters into the liver is hepatic portal vein. Hepatic portal vein carries blood that has been drained from spleen, gastrointestinal tract, and other associated organs. This vein carries blood contain absorbed nutrients from food (Wright, 1993).

Name the major artery and vein that deliver and drain blood to and from the kidneys.

Renal arties are chief artery that supplies blood to the kidney (Wright, 1993). Right and left renal arteries supplies blood to each kidney. Renal veins drains blood from the kidneys.

What are the differences (if any) you noticed between the major arteries and veins in the human versus those in the pig?

Comparing blood supply in pigs and humans, it is evident that pigs have a larger internal thoracid and subscpular arteries compared to humans. This provides for extensive flow of blood (Wright, 1993).

Conclusion:

Deep vein thrombosis or DVT is a condition that leads to formation of blood clots (thrombus) in deep veins. It is a form of inflammation of the vein that leads to clot formation. The conditions mostly affect the leg veins like femoral vein and popliteal vein or the pelvis veins. It is caused by mechanism including decrease in blood flow the damaged blood vessel wall or due to increase tendency of formation of blood clots (Wells, Owen, Doucette, Fergusson, Tran, 2006). Sometimes the veins of the arms are also affected. Although it may sometimes occur without symptoms the affected part will be painful, swollen, red, warm and engorged. Sometimes, the clot may dislodge and travel to lungs leading to pulmonary embolism.

Lab Report: Exercise 5: Cardiovascular Physiology

Purpose: To understand the working of the cardiovascular system

Activity 1: Heart Sounds What is the cardiac cycle?

Cardiac cycle refers to any event that is related to the flow of blood that takes place from the beginning of the heartbeat up to the beginning of the next.

Explain the steps of a cardiac cycle.

There are five stages of a cardiac cycle. First late diastole occurs when semilunar valves close and AV vales open relaxing the heart. Second is arterial systole where artia contract, AV vales open and blood flow to atrium. Third is Isovolumic ventricular contraction where ventricles contract, AV vales close, and no change in volume (Black and Hokanson, 2004). Fourth is ventricular ejection when ventricles empty and semilunar vales open. The last stage is Isovolumic ventricular relaxation where pressure decrease and no blood enters into ventricles, ventricular stops contracting and relax, and semilunars shuts as the blood from aorta push them out.

What do the "lubb" and "dupp" heard through a stethoscope represent?

"lubb" is the first sound that is produced in the heart by the closure of the of two atrio-ventricular vales occurring when the ventricles starts to contract. On the other hand, "dubb" is the second heart sound (Black and Hokanson, 2004). This sound is produced by the closure of the aortic and pulmonary valves. It is the louder aortic valve closure that precedes a quieter triscuspid vale closure.

What is a heart murmur?

Heart murmur is extra heart should, which is produced due to turbulent blood flows sufficient enough to produce audible noise (Black and Hokanson, 2004). Murmurs are usually listened through the stethoscope whiel some may be heard without a stethoscope.

What information can a physician obtain from auscultating your heart with a stethoscope?

Stethoscope is a medical device mainly used for auscultation. It is used to listen to internal sounds of the body. It listens to lung and heart sounds (Wright, 1993). It also listens to intestine and blood flows in arteries and veins. It generates information that can diagnose defect heart, lung, stomach, human fetuses, and others. It can also generate information on abnormal respiratory, cardiac, pleural, arterial, and intestinal sounds.