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BIOC34H3 Lecture Notes - Lecture 7: Third-Degree Atrioventricular Block, Heart Valve, Hypertension

42 views4 pages
cyanmarten183
29 May 2019
School
UTSC
Department
Biological Sciences
Course
BIOC34H3
Professor
Stephen Reid

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Document Summary

Heart failure can be shown on a starling curve which plots sv as a function of edv. It shows that heart failure causes a reduction in sv at any given edv. This can be partially offset by sympathetic stimulation which can enhance ventricular contractility (thereby increasing sv) and can also increase heart rate. Increases in sv and hr lead to increases in co. It takes a smaller edv to achieve a normal sv when sympathetic stimulation (purple) is added to a failing heart (red) although it doesn"t bring sv all the way back to the level in a normal heart (green). One of the most common causes of heart failure is myocardial infarction (heart attack). This happens when cardiac myocytes die due to a blockage of the coronary arteries. The blockages can be a result of fatty deposits or plaque, and begin to show effects as ischemia, or reduced blood flow.

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Related Questions

Question 1

  1. A moderate increase in extracellular potassium will

Increase heart rate due to a more negative EK

Decrease heart rate due to a more negative EK

Increase heart rate due to a less negative EK

Decrease heart rate due to a less negative EK

Question 2

  1. Apply Atropin will directly

Decrease parasympathetic innervation and increase heart rate

Increase parasympathetic innervation and decrease heart rate

Decrease sympathetic innervation and increase heart rate

Increase sympathetic innervation and decrease heart rate

Frog ECG is recorded using

An electrical stimulator

Three wires including the one that is connected to the hook

A force transducer

Three wires and a force transducer

Question 4

  1. How would you differentiate atrial contractions fromventricular contractions?

A.

Observe the heart beating and tap the table to label it

B.

From the size of the contractions

C.

Correlate it with the electrical trace, if the electrical traceis typical.

D.

Both A and C

Question 5

  1. In this week's experiment, _________signal(s) will be recordedto study the frog cardiac functions.

mechanical (contractile)

electrical (ECG)

both mechanical and electrical

blood flow

Question 6

  1. In this week's experiment, the heart is hooked at the________

either atrium or ventricle

ventricle

atrium

sympathetic/increase

parasympathetic/decrease

Sympathetic/decrease

parasympathetic/increase

Question 8

  1. The frog heart can be slowed or stopped by over stimulation ofthe vagus nerve. When apply ACh to the heart, if the frog heartstop beating, you should

Wash the heart with warm Ringers

Apply a few drops of Isuprel

Massage the heart

All of the above

Observe the trace and do nothing

Question 9

  1. The pacemaker in the frog heart is the __________ and thepacemaker in the mammalian heart is the ________

AV, SA node

SV, SA node

SA, SV node

SA, SA node

Question 10

  1. Which of the following statements is TRUE regarding the frogheart

There is no autorhythmic cells found in the frog ventricle.

Oxygenated and deoxygenated blood are mixed completely insidethe frog ventricle

There are two atria and two ventricles.

Deoxygenated blood flows to the frog lungs and skin.

Need 150 word response to the below discussion post

The heart is the most important muscle in your body. The heart is just like a pump that moves the blood throughout the body. This action is what keeps us alive. We are typically taught about the danger of a heart attack, and what we must change in our lives to prevent it; but just like many people, I am at a high risk for heart disease because of family history as well as because of my firefighter career, as heart disease is the number one killer of firefighters (Fire Engineering, 2012). According to the American Heart Association, “both the risk of heart disease and risk factors for heart disease are strongly linked to family history” (American Heart Association, 2016). However, even though your family history provided a picture or marker for possible issues, it is up to us to lower the risk by making changes in our lifestyles.

Heart attacks are caused by blockage that stops blood flow to the heart. A heart attack is when there is damage or death to the heart muscle tissue due to loss of blood supply and this does not necessarily result in an individual's death. A heart attack can show symptoms, such as radiating chest pain or discomfort, dizziness or nausea, sweating, anxiety, stomach pain and shortness of breath. Women have the same symptoms, but they do show some difference in that they describe the pain in their stomach and shoulder blades. In the field we treat heart attack by treating the symptoms; we use IV fluids, baby aspirin, as well as nitroglycerin.

There is another silent killer that most people do not hear much about or they think it is the same thing as a heart attack. As a medic, I deal with this life and death situation all the time, and it interesting to see how many people are not aware of the difference of a heart attack and a sudden cardiac arrest. Sudden cardiac arrest is the abrupt loss of heart function in a person who may or may not have diagnosed heart disease. This can happen at any time, its unexpected and occurs instantly, or seconds after symptoms occur. Cardiac arrest is caused when the heart’s electrical system malfunctions. This causes the heart to go into and irregular heart rhythm (ventricular fibrillation). When this happens, the hearts lower chambers suddenly start quivering and this stops the pump of blood in the heart. The only thing that can reverse cardiac arrest is early defibrillation and CPR. Most people think that a defibrillator can be used on heart attack patients, but this is not the case. The defibrillator is used to shock the heart and restore the normal heart rhythm, if the heart stops, then CPR has to be performed.

Unlike a heart attack, sudden cardiac arrest can happen to anyone, no matter how health or fit they are. According to the American Heart Association “cardiac arrest is a leading cause of death, nearly 360,000 out-of-hospital cardiac arrest occur annually in the United States” (American Heart Association, 2016).

Question 1 (1 point)Save Question 1Save
Which of the following will increase blood flow to a given regionof the body?

A smaller pressure gradient between the arteries and thatregion.

Vasoconstriction of the arterioles feeding that region.

An increase in blood viscosity via dehydration.

An increase in diameter of the arterioles feeding the region.
Question 2 (1 point)Save Question 2Save
Which of the following statements pertaining to the innervation ofthe heart is TRUE?

The heart is directly activated by the somatic nervoussystem.

The heart muscle is directly activated by the autonomic nervoussystem.

NE released by sympathetic neurons binds to beta-adrenergicreceptors and increases heart rate.

ACh released by parasympathetic neurons binds to nicotinicreceptors and decreases heart rate.
Question 3 (1 point)Save Question 3Save
The prolonged depolarization in cardiac myocytes is due primarilyto which channel type?

Voltage-gated sodium channels

Voltage-gated potassium channels

Funny (F-type) sodium channels

Long-lasting (L-type) calcium channels
Question 4 (1 point)Save Question 4Save
Which of the following statements about the pacemaker potentialgenerated by the SA node is FALSE?

Its intrinsic rate is about 70 depolarizations per minute.

The rate of depolarization can be affected by autonomicinnervation.

Funny (F-type) sodium channels play a role in the gradualdepolarization.

In the complete absence of extrinsic input (hormones or neurons),the SA node will continue to depolarize
Question 5 (1 point)Save Question 5Save
Match the description in the left hand column with the terms in theright hand column that BEST correspond (one match per term, allselections are used).

The period of the cardiac cycle when the heart is contracting

The period during diastole when the pressure in the atria exceedsthe pressure in the ventricles.

The period during systole when all heart valves are closed.

The difference between end-diastolic volume and end-systolicvolume.

The period of the cardiac cycle when the heart is relaxing.

1.
Systole
2.
Diastole
3.
Stroke volume
4.
Isovolumetric contraction
5.
Ventricular filling