Heart Physiology

Question 1

What three layers compose the heart wall?

Answer 1

Epicardium- Outside
Myocardium- Middle
Endocardium- Inner

Question 2

The epicardium is a ________ membrane overlying a layer of ________ tissue.

Answer 2

Serous

Areolar

Question 3

What kind of cells compose the serous membrane of the epicardium?

Answer 3

Simple squamous

Question 4

The surface of the epicardium is ________.

Answer 4

Slippery

Question 5

This epicardium also has ______ tissue to protect the _______ vessels.

Answer 5

Fatty

Coronary

Question 6

This layer composes the bulk of the heart wall

Answer 6

Myocardium

Question 7

What composes the “fibrinous skeleton” of myocardium?

Answer 7

A meshwork of collagenous and elastic fibers

Question 8

What are the three functions of the “fibrinous skeleton” of the myocardium?

Answer 8

• Provide structural support
• Limits the routes that electrical signals can travel
• Pushes blood up from the apex to the base “squeezing” blood up, allowing blood to exit at the base of the heart

Question 9

What is the innermost layer of the heart wall?

Answer 9

Endocardium

Question 10

What tissue types is the endocardium made from?

Answer 10

Endothelium (simple squamous epithelium) overlying a thin layer of connective tissue.

Question 11

The endocardium is continuous with the ________ of blood vessels.

Answer 11

Endothelium

Question 12

What are the trabeculae carneae?

Answer 12

Irregular ridges of muscle in the ventricles

“Crossbars of flesh”

Question 13

What covers the trabeculae carneae and pectinate muscles?

Answer 13

Endocardium

Question 14

What are the pectinate muscles?

Answer 14

Ridges of muscle in the anterior wall of the right atrium (and its auricle), and auricle of left atrium.

Not found anywhere else in the left atrium, or on posterior wall of right atrium

Question 15

What is the pericardium? What two layers is it made from?

Answer 15

Two protective layers surrounding the heart, a double-walled sac
Fibrous pericardium
Serous Pericardium

Question 16

Where is the fibrous pericardium? What is it made from?

Answer 16

Outside. Tough, inelastic, dense fibrous CT

Question 17

What are the three functions of the fibrous pericardium?

Answer 17

Protects the heart (like sclera protects the eye)
Anchors the heart to its surrounding structures, like the diaphragm or great vessels
Prevents the heart from overfilling with blood

Question 18

What is the serous pericardium, in general?

Answer 18

Internal, made of 2 layers

In general, thin, slippery membrane, more delicate

Question 19

What two layers make the serous pericardium?

Answer 19

Parietal Layer of the serous pericardium

Visceral layer of the serous pericardium (AKA epicardium)

Question 20

The parietal layer of the serous pericardium is attached to…

Answer 20

Fibrous pericardium

Question 21

What, and how much, fills the gap between the parietal and visceral layers of the serous pericardium?

Answer 21

Pericardial fluid. 5-30ml

Question 22

What does pericardial fluid do?

Answer 22

Reduces friction, making the layers slippery

Question 23

From inside to out, name the layers of the heart wall

Answer 23

Endocardium
Myocardium
Epicardium/ visceral layer of serous pericardium
Pericardial fluid
Parietal layer of the serous pericardium
Fibrous layer of pericardium

Question 24

What is pericarditis? Definition and what’s happening

Answer 24

Inflammation of pericardium
Hinders production of serous fluid
Roughens serous membrane surfaces which hurts, friction pain with each heartbeat

Question 25

What is cardiac tamponade?

Answer 25

Compression of heart by an abnormal accumulation of fluid in pericardial sac

Question 26

Cardiac tamponade interferes with ______ filling, so it _______ the heart.

Answer 26

Ventricular

Compresses

Question 27

What is the Tx for cardiac tampinade?

Answer 27

Insert a syringe into the pericardial cavity to remove fluid

Question 28

What is RHD? How does it develop?

Answer 28

Rheumatic Heart Disease
May develop after strep throat if not resolved well. Heart valves are damaged, but are repaired with more fiber, which causes scarring. Can reemerge if patient has strep again.

Question 29

What is ischemic heart tissue? What can cause it?

Answer 29

Tissue that isn’t receiving enough oxygen, inadequate blood flow or a blockage of a coronary artery

Question 30

How do I tell if there’s ischemia on an EKG?

Answer 30

ST elevation

Question 31

What procedure can be done to test for ischemia? Why?

Answer 31

A stress test

At rest can appear normal, but it shows during exercise

Question 32

What is angina pectoris? At the cellular level?

Answer 32

Thoracic pain caused by fleeting deficiency of blood flow (O2) to the myocardium. So increase in lactic acid production as heart goes into anaerobic fermentation, which stimulates pain receptors in the heart.

Question 33

Where is pain felt with angina pectoris? How can it be treated?

Answer 33

Substernal pain, radiating to the left shoulder. Treat with sublingual nitroglycerin, a vasodilator

Question 34

What is an MI?

Answer 34

Myocardial Infarction- If anaerobic respiration occurs for more than a few minutes then cell death (necrosis) occurs

Question 35

MI’s are called _____ _____, and __% of patients die before being seen medically.

Answer 35

heart attacks

25%

Question 36

Can cardiocytes heal? What develops from their death?

Answer 36

No.

Scar tissue

Question 37

How do I see an MI on an EKG?

Answer 37

Enhanced Q wave or elevated ST segment

Question 38

What is Creatine phosphokinase?

Answer 38

An enzyme whose levels increase in blood

Cardiocytes break down and release this enzyme to blood, levels ↑ 3-6 hours after MI, returning to normal 3 days after

Question 39

What is troponin I?

Answer 39

Protein released by dead or damged heart cell in blood
This is an extremely sensitive test, released days or weeks after an MI, therefore allows a longer timefrsme to diagnose an MI