Bio261 Lecture 17 Q's- Human Ecg's & Innate Immunology

Front 1

What does ECG stand for?

Back 1

- Electrocardiogram

Front 2

What is an ECG/EKG?

Back 2

- It is an electrical record of the hearts electrical events.

Front 3

Are the axis of the heart and the major dipole of the heart related?

Back 3

- The axis of the heart is a calculation that is made by comparing the "view" of the dipole from two different leads. Using the comparison, this allows you to identify the major dipole direction.

Front 4

What is the major electrical connection between the atria and the ventricles?

Back 4

-The major electrical connection between the atria and the ventricles is the AV node (atrioventricular node), without this connection there would be no electrical cross-talk between the atria and the ventricles.

Front 5

What are the major events seen in an ECG, and what does each indicate?

Back 5

- The p-wave corresponds to the initiation of the depolarization of the atrial contracting cells.

-The QRS complex corresponds to the initiation of the depolarization of the ventricular contracting cells and also has the atrial repolarization event buried in the signal.

-The t-wave corresponds to the initiation of the repolarization of the ventricular contracting cells.

Front 6

What are the normal time intervals of each segment of the ECG?

Back 6

-P-R interval = 0.12-0.20sec

-QRS complex = under 0.10 sec

-Q-T interval under 0.38 sec

Front 7

What does axis of the lead refer to?

Back 7

- The arrangement of the negative and positive electrodes of the lead

Front 8

What 4 pieces of information, that we discussed in class. can you obtain from an ECG?

Back 8

1. Heart rate.

2. Presence of arrhythmias.

3. Presence of myopathes (ischemic areas).

4. Problems with the conducting system.

Front 9

What is bradycardia?

Back 9

- Bradycardia is an extremely slow resting heart rate (<60 bpm).

Front 10

What is tachycardia?

Back 10

- Tachycardia is an extremely high resting heart rate (>100 bpm).

Front 11

Are they ever considered normal?

Back 11

- Bradycardia normally occurs when we sleep, and also well trained atheletes have resting heart rates that can be <60 bpm.

-At rest, tachycardia is not considered normal, but with exercise, heart rates will easily become >100 bpm.

Front 12

What type of arrhythmia is life-threatening?

Back 12

- Ventricular fibrillation.

Front 13

Describe what is happening in the condition know as AV node heart block.

Back 13

-Heart block is a condition in which the AV node begins to deteriorate (or die). As heart block progresses, the ventricles will slowly start to beat at the rate of the pacemaker potentials of the Purkinje fibers

Front 14

What characterizes each phase of AV node block?

Back 14

1st degree - longer than normal P-R interval

2nd degree - not all atrial depolarization events sent to the ventricles, detected on the ECG by having some P-waves that do not have QRS complexes following them

3rd degree (complete) - when atria and ventricles are beating at completely different paces.

Front 15

What are the pacemaker potential rates for the different conducting cells of the heart?

Back 15

- The rates of the pacemaker cells are as follows: SA node = ~100 bpm, but because of parasympathetic dominance, it is slowed to~ 75-80 bpm; the AV node ~ 60 bpm; and the Bundle of His/Purkinje fibers ~20-40 bpm.

Front 16

What events are seen in an ECG that correspond to a PVC?

Back 16

- In an ECG, the events that occur with a PVC are

1. No p-wave.

2. Both an enlarged and spread out QRS complex.

3. A compensatory pause.

Front 17

What are the 2 categories of defense mechanisms in our bodies?

Back 17

The 2 categories of defense are innate and adaptive immunity.

Front 18

Which cells are primarily involved in each?

Back 18

-Innate immunity involves phagocytic cells, such as neutrophils and macrophages; adaptive immunity involves lymphocytes (B and T-cells).

Front 19

What is innate immunity?

Back 19

-Innate immunity is our primary form of attack against a pathogen

Front 20

Is it considered a specific or non-specific response?

Back 20

- It non-specifically attacks substances that are perceived as "non-self".

Front 21

What is phagocytosis?

Back 21

-Phagocytosis is the process in which a cell or a foreign substance in engulfed so that it can be degraded.

Front 22

What types of cells do this?

Back 22

- The cells which perform phagocytosis are netrophils and monocytes/macrophages.

Front 23

What are the two terms that refer to the movement of WBC from the blood into the tissues?

Back 23

- Movement of WBC's our of the blood stream and into the tissues is called diapedesis or extravasation

Front 24

What is adaptive immunity?

Back 24

- Adaptive immunity is immunity that is very specific to a particular antigen

Front 25

What is a pathogen?

Back 25

- A pathogen is any substance capable of causing disease

Front 26

Examples?

Back 26

- Examples are bacteria, viruses, or parasites.

Front 27

Can any foreign molecule act as an antigen?

Back 27

-No, most antigens are proteins and must be of a certain size

Front 28

What mechanisms are involved in local inflammation?

Back 28

-Both innate and adaptive.

Front 29

What type of cells release histamine?

Back 29

- Histamine is released by mast cells (which are derived from basophils).

Front 30

During inflammation, what changes occur in the local capillaries and what causes it?

Back 30

- Primarily due to the release of histamine, heparin, and prostaglandins from Mast cells, the vessels vasodilate, allowing more blood flow to the area, also, the histamine causes the pores in the endothelial cells to enlarge, making the vessels more permeable.

Front 31

Why does the area swell?

Back 31

-An area will swell at a site of inflamation because mast cells secrete heparin, histamine, prostaglandins, leukotrienes, cytokines, & TNF-a. All of these produce redness, swelling, pus, & pain. (The redness is from enhanced blood flow to the area, the swelling is from more fluid and cells entering the interstitial space, the pus is from an accumulation of WBC’s that are engulfing the pathogen and sometimes dying from toxins produced by those pathogens, and pain is associated with more fluid in the interstitial space as well as activation of pain receptors by some of the chemicals produced by the pathogens)

Front 32

Electrocardiogram

Back 32

-An electrical activity record of the heart, using surface electrodes (can be done on any animal)

Front 33

Dipole

Back 33

-a separation of electrically charged regions

Front 34

Sinoatrial (SA) node

Back 34

-a small, specialized region in the right atrial wall

-the normal pacemaker of the heart

Front 35

Internodal pathway

Back 35

-the pathway b/n the SA node and AV node

Front 36

Atrioventricular (AV) node

Back 36

-a small bundle of specialized cardiac muscle cells located at the base of the right atrium near the septum

Front 37

Bundle of His

Back 37

-a tract of specialized cells that originates at the AV node and enters the septum b/n the ventricles.

Front 38

Purkinje fibers

Back 38

-small terminal fibers that extend from the bundle of His and spread throughout the ventricular myocardium much like small twigs of a tree branch

Front 39

QRS complex

Back 39

-ventricular depolarization and atria repolarization

Front 40

T-wave

Back 40

-ventricular repolarization

Front 41

P-R interval

Back 41

-AV nodal delay (1/10th of a sec)

Front 42

Arrhythmia

Back 42

-irregular heartbeats

Front 43

Myopathes

Back 43

-damage to heart walls

Front 44

Bradycardia

Back 44

-abnormal heart rate of <60/min

Front 45

Tachycardia

Back 45

-abnormal heart rate of >100/min

Front 46

Flutter

Back 46

-contraction rates of 200-300/min

-arrhythmias detected on ECG

Front 47

Fibrillation

Back 47

-myocardial cell depolarizations become asynchronous- the heart begins to quiver and no blood is pumped to the body

Front 48

Electrical defibrillation

Back 48

-resynchronizes heart by depolarizing all cells at the same time

Front 49

1st degree (primary) AV block (PR > 0.2 sec)

Back 49

-when conduction thru AV node > 0.2 sec

-causes long P-R interval

Front 50

2nd degree (secondary) AV block

Back 50

-when only 1 out of 2-4 atrial APs can pass to ventricles

-causes P waves w/no QRS

Front 51

3rd degree (complete) AV block

Back 51

-no atrial activity passes to ventricles

-ventricles driven slowly by bundle of His or purkinjes

Front 52

Self vs. Non-self

Back 52

-innate (nonspecific) immunity vs. adaptive (specific) immunity

Front 53

Innate immunity

Back 53

-nonspecific

-inherited as a part of structure of each organism

-1st line of defense against invading pathogens

-includes phagocytic cells, epithelial barriers, high acidity of gastric juice & fever

Front 54

Adaptive immunity

Back 54

-specific

-a function of lymphocytes & changes w/exposure

Front 55

PAMP's (pathogen associated molecular patterms)

Back 55

-produced by only microorganisms

-trigger phagocytosis

Front 56

LPS (Lipopolysaccharides) -gram neg.

Back 56

-toll-like receptors (TLRs) on the innate immune cells that are responsible for recognizing the PAMP's on the microorganisms

Front 57

Peptidoglycan – gram pos.

Back 57

-toll-like receptors (TLRs) on the innate immune cells that are responsible for recognizing the PAMP's on the microorganisms

Front 58

Extravasation

Back 58

-how WBCs exit capillaries from blood (diapedesis)

Front 59

Diapedesis

Back 59

-aka extravasation

Front 60

Pyrogens

Back 60

-released by WBCs in response to endotoxins from Gm- bacteria

Front 61

Antigen

Back 61

-molecules that elicit production of antibodies that specifically bind those antigens

-usually foreign molecules to the body

Front 62

Antibodies

Back 62

-recognize antigens of foreign microorganisms and cause an immune response

Front 63

Opsinization

Back 63

-the promotion of phagocytic activity of neutrophils, macrophages & monocytes

-caused by attachment of antibodies to antigens as inflammation progresses

Front 64

Mast cells

Back 64

-release histamine, causing inflammatory response

Front 65

Heparin

Back 65

-Prevents clots in the blood vessels before or after surgery or during certain medical procedures. Also treats certain blood, heart, and lung disorders and helps diagnose and treat certain bleeding disorders. This medicine is a blood thinner.

Front 66

Histamine

Back 66

-cause the "flare and wheal" rxn of inflammation. Flare is the spreading flush/redness caused by some RBC's being able to enter or are getting closer to the skin surface; wheal is the elevated area due to edema

Front 67

Leukotrienes

Back 67

-Leukotrienes use lipid signaling to convey information to either the cell producing them (autocrine signaling) or neighboring cells (paracrine signaling) in order to regulate immune responses.

- Leukotriene production is usually accompanied by the production of histamine andprostaglandins, which also act as inflammatory mediators.

-trigger contractions in the smooth muscles lining the bronchioles; their overproduction is a major cause of inflammation in asthma and allergic rhinitis.