Chapter 17 - Heart - Learning Outcomes

Question 1

Where is the heart located in the human body?

Answer 1

Thoracic region, specifically in the mediastinum, and above the diaphragm.

Question 2

What surrounds the heart to protect it?

Answer 2

Ribs, lungs, muscles, and skin.

Question 3

What type of tissue is the heart made of?

Answer 3

Cardiac muscle

Question 4

How many chambers does a typical human heart have?

Answer 4

4 chambers : right and left atrium and ventricles.

Question 5

How many valves does a typical human heart have?

Answer 5

4 valves : aortic, pulmonary, tricuspid, bicuspid.

Question 6

What blood vessels move through different portions of the heart?

Answer 6

Arteries and Veins

Question 7

What is the difference between the pulmonary and systemic circuit?

Answer 7

Pulmonary: moves blood between heart and lungs.
Systemic: moves blood between heart and body.

Question 8

What serous membrane surrounds the heart?

Answer 8

Pericardium

Question 9

What are some major anatomical and functional differences between the left and right side of the heart?

Answer 9

Right side: pumps blood to lungs and has thinner walls.
Left side: pumps blood to whole body and has thicker walls.

Question 10

Why does the heart need its own circulation?

Answer 10

In order to be able to function and pump blood to the body.

Question 11

What does a typical cardiac muscle cell look like?

Answer 11

tubular structure composed of chains of myofibrlis, which are rod-like units in a cell.

Question 12

What is the difference between a contractile cardiac muscle cell and a pacemaker cell?

Answer 12

Cardiac muscle cells help contract the muscles, pacemaker cells provide the energy needed to contract the cardiac muscles.

Question 13

What % of pacemaker cells are in the heart compared to cardiac muscle cells?

Answer 13

1% pacemaker cells, 99% cardiac muscle cells

Question 14

In what region of the heart are pacemaker cells found?

Answer 14

Right atrium

Question 15

How is the electrical signal of pacemaker cells conducted?

Answer 15

SA Node > Atrial Conducting Fibers > AV Node > Right or Left Bundle Branch > Purkinje Fibers

Question 16

Compare the action potential generated in a contractile cell vs. pacemaker cell.

Answer 16

Contractile cell using sodium channels vs. pacemaker cells which use calcium channels to create their action potentials

Question 17

What is the “refractory” period in a muscle cell?

Answer 17

The amount of time blood takes to fill in to the heart

Question 18

How does the “refractory” period differ in cardiac vs. skeletal muscle? And why?

Answer 18

Refractory period is longer in cardiac muscle cells vs. skeletal muscle cells. It is longer to allow the heart to fully contract and then relax while filling with blood before pumping again