Unit 4 Study Guide
Heart Rate
A measure of cardiac activity usually expressed as the number of beats per minute.
Electrocardiogram (EKG)
A measurement of heart electrical activity.
Sinoatrial Node
A small mass of tissue that is made up of Purkinje fibers, ganglion cells, and nerve fibers, that is embedded in the musculature of the right atrium, and that originates the impulses stimulating the heartbeat -- called also S-A node, sinus node.
Atrioventricular Node
A specialized mass of conducting cells located at the atrioventricular junction in the heart.
Mitral Valve
A valve in the heart that guards the opening between the left atrium and the left ventricle; prevents the blood in the ventricle from returning to the atrium. Alternative name is bicuspid valve.
Tricuspid Valve
A valve that is situated at the opening of the right atrium of the heart into the right ventricle and that resembles the mitral valve in structure but consists of three triangular membranous flaps.
What structural differences did you notice between arteries and veins? Relate these differences to the function of the vessels.
Arteries and arterioles have thicker walls than veins. The increased amount of smooth muscle that are found in arteries give them extra strength and elasticity to deal with the surges of blood from the heart. Veins have valves within them to prevent backflow of blood. Veins have wider inner diameters which means that they can hold more blood. Veins have to have more blood in them than the arteries.
Diastolic Pressure
Blood pressure that remains between heart contractions.
Anna's autopsy report noted mitral valve prolapse. This means that the mitral valve does not close properly. Explain why this could be a problem.
Blood will not move in the right direction, and the body will not get the oxidized blood it needs.
Why do you think it is important to take an average resting heart rate versus relying on one value
External factors can impact the heart rate such as previous positions, temperature, previous physical activity, etc.
At the time of her cardiac work-up, Anna Garcia had an average resting heart rate of 98bpm. What does this say about her overall heart health?
Her heart is not at a healthy rate. Which means that her heart requires more to pump blood to the rest of her body. This may overwork the heart, and cause other health problems.
Explain how an ACE inhibitor might have helped Anna mediate her blood pressure.
It works by blocking the body from producing a chemical called angiotensin II it enters the blood stream, and makes your blood vessels become narrower, which gives your blood less room to move (raises blood pressure). The ACE inhibitor stops this chemical, and in turn relaxing the blood vessels and lowers blood pressure.
What is prehypertension? Why do you think it is valuable to know if you are considered prehypertensive?
Prehypertension is a case before stage one of high blood pressure. It is valuable to know so that you can make proper changes to your lifestyle in order to keep your blood pressure at a healthy level.
Blood Pressure
Pressure exerted by the blood upon the walls of the blood vessels, especially arteries, usually measured by means of a sphygmomanometer and expressed in millimeters of mercury.
In most of the body, the arteries carry oxygenated blood and the veins carry deoxygenated blood. The exception to this pattern is the heart. Explain how and why specific arteries and veins of the heart are different from the pattern seen in the rest of the body.
Pulmonary veins transport oxygenated blood from the lungs to the heart. This is different from the rest of the body bc the veins are supposed to carry deoxygenated blood.
Explain what an EKG can tell a physician about the heart of a specific patient.
The EKG can tell irregular heartbeat, irregular speed of contractions, angina, or even tissue death
Describe how the structure of the aorta relates to its function in the heart.
The aorta is a tube that transports the oxidized blood to the rest of the body. It needs to be bigger because it must push all the blood through the rest of the body.
Systemic Circulation
The branch of the circulatory system that supplies all body organs and then returns oxygen-poor blood to the right atrium via the veins.
Anna's autopsy revealed that she had an external pacemaker. What does the pacemaker replace in the heart? Explain.
The electrical charge which is what makes the heart contract and pushes the blood through the body. The pacemaker is needed for regular beats and putting the blood through the whole paper. SA node
Using what you have learned about the structure and function of the heart, explain why left ventricular hypertrophy can be fatal if left untreated.
The enlarged muscle loses elasticity and stiffens, preventing the chamber from filling properly and leading to increased pressure in the heart. The enlarged muscle tissue compresses its own blood vessels (coronary arteries) and may restrict its own supply of blood. The overworked muscle weakens.
Aorta
The large arterial trunk that carries blood from the heart to be distributed by branch arteries through the body.
What are two differences you see when comparing the four chambers of the heart? Relate these differences to the function of each chamber.
The left chambers are larger than the right chambers. The right atrium and ventricle function is for transporting deoxidized blood, while the left atrium and ventricle functions for transporting oxidized blood.
Which chamber of the heart do you think is the most muscular? Explain your reasoning.
The left ventricle because it is in charge pumping blood through the aorta.
Pulmonary Circulation
The passage of venous blood from the right atrium of the heart through the right ventricle and pulmonary arteries to the lungs where it is oxygenated and its return via the pulmonary veins to enter the left atrium and participate in systemic circulation.
Systolic Pressure
The pressure generated by the left ventricle during systole
Pulse
The rhythmic expansion and recoil of arteries resulting from heart contraction; can be felt from the outside of the body
Aortic Valve
The semilunar valve separating the aorta from the left ventricle that prevents blood from flowing back into the left ventricle.
Systole
The stage of the heart cycle in which the heart muscle contracts and the chambers pump blood.
Cardiovascular System
The transport system of the body responsible for carrying oxygen and nutrients to the body and carrying away carbon dioxide and other wastes; composed of the heart, blood vessels, and blood.
Now that you have seen a heart up close, explain how the actual structure differs from your heart box study tool.
The ventricles and atria are different sizes and thicknesses to fit the needs of the right and left parts of the heart.
What do you think would happen in the heart if the AV node could no longer do its job? Explain how this would affect the contraction of the heart and the movement of blood.
The ventricles would not have the electrical charge needed to contract, and the blood would not be able to move through the rest of the body.
What are two causes of blood pressure changes that might occur in a person within a given day?
a. Eating. Nutrients such as sodium, could change the blood pressure. These changes may be minor, but the food we eat affects our body and how it acts. b. Position. Different positions require different requirements from your body, some might take more energy
What are some factors that can increase or decrease the heart rate and the beat you feel at each pulse point?
• Raise - stimulants, emotions, drugs, activity • Lower - position, drugs (depressants), alcohol
Inferior Vena Cava
A vein that is the largest vein in the human body and returns blood to the right atrium of the heart from bodily parts below the diaphragm.
Superior Vena Cava
A vein that is the second largest vein in the human body and returns blood to the right atrium of the heart from the upper half of the body.
Vein
A vessel that returns blood to the heart
Hypertension
An abnormally high blood pressure
Atrium
An anatomical cavity or passage; especially a chamber of the heart that receives blood from the veins and forces it into a ventricle or ventricles.
Pacemaker
An electrical device for stimulating or steadying the heartbeat or reestablishing the rhythm of an arrested heart.
Tissue
An integrated group of cells with a common function, structure, or both.
Artery
Any of the tubular branching muscular and elastic-walled vessels that carry blood from the heart through the body.
Valve
A body structure that temporarily closes a passage or orifice, or permits movement of fluid in only one direction
A growing fetus has a vessel, the ductus arteriosus, in the heart that connects the pulmonary artery with the aorta and conducts blood directly from the right ventricle to the aorta. Why do you think this vessel closes soon after birth?
The vessel closes to have full separation between oxygenated blood and deoxygenated blood. The right atrium and ventricle are supposed to transport the deoxygenated blood, and the left atrium and ventricle are supposed to transport the oxygenated blood and then transfer to the aorta, where the blood will go to the rest of the body.
Propose reasons why the heart rates of different people are different when exposed to the same stressor or to the same physical activity, even though their resting heart rates are the same
The way the brain may react to the stressor or physical activity. Also due to the physical health of the individual, and rather they are healthy or not.
Describe the mechanisms in place to prevent the blood from flowing in the wrong direction through the heart.
There are valves on the connecting arteries, they prevent the blood from flowing in the wrong direction.
Explain what happens to tissues, such as the heart, or the brain, if oxygenated blood is not delivered in a timely manner.
Tissue starts to die, then the organs will fail then the body will not be able to operate and die. This is especially in the brain, brain tissues rely on oxygen, and without, significant brain damage can occur.
