Heart Dissection Lab

SHEEP HEART DISSECTION

CIRCULATORY CYCLE DISSECTION

Q1: What is the purpose of the pericardium?
The pericardium is a double-layered, membrane surrounding the heart and base roots of the major blood vessels leading into and out of the heart. It plays an important role in protecting and stabilizing the heart by limiting the size of the organ.


Q2: Observe the blood vessels connecting to the heart. How do arteries differ from veins in their structure?
Arteries have three layers: a smooth inner layer, a muscular layer, and a thin outer layer, and connective fibers in artery walls. Veins have less elasticity in the walls and are less muscular.


Q3: Place your finger inside the auricle. What function do you think the auricle serves?
The left auricle is a decompression chamber when atrial blood pressure is high.


Q4: Observe the external structures of the atria and ventricles. What differences do you observe?
Atria make up the top chambers of the heart and ventricles make up the bottom chambers. The right part of the heart receives unoxygenized blood and sends it from ventricles to the atria. Atria are smaller cavities but the ventricles seem to be larger cavities.

Q5: 


Coronary sinus

Inferior vena cava















Tricuspid valve


Q6: 

Q7: Why is the “anchoring” of the heart valves by the chordate tendinae and the papillary muscle important to heart function?
The papillary muscles anchoring the cords to the heart wall will contract to counter any stretch in the cord during vigorous pumping of the heart.


Q9: What is the function of the semi-lunar valves?
The semilunar valves act to prevent back flow of blood from the arteries to the ventricles during ventricular diastole, and to help maintain pressure on the major arteries.


Q10: Valvular heart disease is when one of more heart valves does not work properly. Improperly functioning heart valves can lead to regurgitation, which is the backflow of blood through a leaky valve. Ultimately this can lead to congestive heart failure, a condition that can be life threatening.

a. If the valve disease occurs on the right side of the heart, it results in swelling in the feet and ankles. Why might this happen?
The right side of the heart results in the swelling in the feet because the right side pumps blood to the lower side of the body. Reduced blood flow results in swelling.


b. If the valve disease occurs on the left side of the heart, what complications would you expect to see?
Failure in a valve in the left side of the heart – the aortic or the mitral valve – results in left-sided heart failure. This leads to an accumulation of fluids in the lungs, or pulmonary oedema.


Q12: Describe how the left and right sides of the heart differ from each other.The right side of the heart pumps blood to the lungs to pick up oxygen. The left side of the heart receives the oxygen-rich blood from the lungs and pumps it to the body.


Q13: Draw and label all structures visible in the interior of the cross-section.

Unit 3 Reflection

Content Reflection

Last year in AP Biology, we touched on the pulmonary veins and its molecular significance of being a specific part. In this unit of Anatomy and Physiology, we learned about the circulatory system's functions and main parts. Major components of the circulatory system include the heart, network of tubes, and blood. Accessory organs include lungs, kidneys, and intestines. Blood pressure is a measure of the force exerted on the wall of the arteries. Blood pressure includes systolic pressure (result of the contraction of the ventricles) and diastolic pressure (result of ventricle relaxation). Blood pressure varies with weight, race, mood, activity level, and posture. 

The human heart has three layers of wall: epicardium, myocardium, and endocardium. There are four hollow chambers of the heart: the right atria, right ventricle, left atria, and left ventricle. The atria and ventricles are separated by the interventricular septum, which divides the heart longitudinally. The pericardium of the heart lubricates the heart so that there is less friction. The four chambers of the heart are used to receive and discharge blood and carbon dioxide. The SA node is found in the right atrium and is one of the reasons our heart pumps regularly. When impulses move from the SA node to the AV node, the heart contracts. The cardiac cycle is the systole and diastole of both atria and both ventricles. 

The arteries carry blood from the heart while capillaries connect arterioles to venules. Capillaries have thin walls and exchange gases between the blood and body. A thin weakened section of a blood vessel wall can cause an aneurysm. It can be treated with a stent graft inserted through the femoral artery. Atherosclerosis, a buildup of plaque in the arteries, can be prevented by eating less fats in a diet. 

Sickle cell anemia, which got its name from the shape of the blood cell, results in an inadequate amount of oxygen provided to the body. Healthy red blood cells have no nucleus or genetic material. Neutrophils are active phagocytes that ingest bacteria. Basophils stimulate inflammation by releasing histamines. Eosinophils fight parasitic worms and inactivate inflammatory chemicals. Monocytes destroy more microbes than neutrophils. Platelets are cell fragments and initiate chain reactions that leads to blood clotting. 

Heart attacks, caused by atherosclerosis of the coronary arteries, results in reduced blood flow. Cardiac arrest occurs when there is an electrical malfunction. There are two types of cholesterol, LDL (which sticks to arteries) and HDL (which cleans up the LDL). Angiography is when dye is injected in order to determine the issue. Echocardiograms produce images of the heart with sound waves. Hemorrhagic strokes occur when an artery in the brain bursts while ischemic strokes occur when an artery supplying the brain becomes blocked. 

The nose contains the sinuses, which are air pockets in the skull bones. The pharynx is the passageway for food and air. The lungs are air sacks and contain the aveolar sac, which contains the alveoli. The larynx contains the epiglottis and is the voice box. Chronic bronchitis is the inflammation of the bronchioles with increased mucous production. 

Reflect on your learning process and self growth 

I believe that I work better in group environments when it comes to studying or remembering terms. I still find the memorization of the heart terminology to be very difficult, but that is only because my memory is weak. I did worse this unit because I failed to create more study guides to supplement my classroom knowledge. 

This unit, I was able to sleep more due to the outlining of my goals. When I realized my problem, I worked towards solving it by finishing homework earlier and studying in advance. My diet is still fairly poor due to lack of change in this area, but I will work on this long term goal for the future.