Test #1 Flashcards
Name the small openings in the aortic arch, just past the aortic valve.
Orifices of coronary arteries
Describe the muscular attachments of the heart.
There are none; it hangs from the aorta
Name the 3 sizes of cardiac cells and their primary function
Small: weakly contractile, auto rhythmic, slow AP conduction
Intermediate: strongly contractile, make up bulk of heart
Large: weakly contractile, specialized for fast impulse conduction
What is the average and mean pressures of the pulmonary and systemic circuits and heart chambers?
R. Atrium: 2 R. Ventricle: 25 Pulmonary circuit: 25/8 (mean:14) L. Atrium: 5 R. Ventricle: 120 Systemic arteries: 120/80 (mean: 93) Veins: 10
Define cor pulmonare.
Enlargement of right side of heart..
What are the 3 variable that affect stroke volume?
EDV (end diastolic volume or preload)
TPR (total peripheral resistance or after load)
Contractility (frank starlings law)
Compare the amount of blood/oxygen supply going to the heart during rest vs. heavy exercise.
Unchanged: cardiac supply remains consistent at about 4-5%
Musculoskeletal goes from 15-20% to 80-85%
Explain the electrical conduction system in a healthy heart.
SA (sinoatrial) node, AV (atrioventricular) node, Bundle of His (L & R bundle branches), purkinje fiber system
What ion causes an action potential (depolarization) to occur in auto rhythmic cardiac cells?
Ca+2 (calcium ion)
What are the 3 phases of an action potential for SA & AV cell?
Phase 4: spontaneous depolarization
Phase 0: full depolarization
Phase 3: repolarization
Name the 4 phases of an action potental in cardiac CONTRACTILE cells.
Phase 4: table resting potential Phase 0: full depolarization Phase 1: initial repolarization Phase 2: calcium plateau Phase 3: repolarization
During cardioversion, which part of the heart cycle does the monitor sync and shock?
R wave - this avoids the “vulnerable period” of the cycle (middle to end of t wave)
How does the parasympathetic system slow heart rate?
increases the cells permeability to K+ (potassium ion) which allows K+ to leak and the cell becomes hyperpolarized (more negative) reducing the likelihood of an AP
How does the sympathetic system affect heart rate?
Decrease K+ leaving the cell, increases slow intake of Ca++ and Na+ to cause faster cell depolarization
Describe the mechanism of a sodium channel blocker.
Blocks sodium channels responsible for (phase 0) depolarization. This decreases the slope and amplitude of depolarization.
Describe the mechanism of a Potassium channel blocker.
Blocks the potassium channels responsible for (phase 3) repolarization. This increases AP duration and refractory period.
Describe the mechanism of a Calcium channel blocker.
Block calcium channels on vascular smooth muscle, cardiac myocytes, and cardiac nodal tissue. This causes vasodilation, decreased cardiac force, decreased heart rate, and decreased conduction velocity.
Define the mechanism of Beta-blockers
Blocks action of nor-epi at beta 1 receptors in the heart
Define Coranary Heart Disease
Reduced blood flow to coronary arteries causes hypoxia, impaired function, and leads to infarction.
What is the diaphragm of the stethoscope best for hearing?
Heart, respiratory, bowel (higher pitched sounds)
What is the bell of the stethoscope best for hearing?
Low pitched sounds: Bruits, murmurs, AAA
What are the 6 components of a pre-hospital initial assessment?
- General Impression
- Airway
- Breathing
- Circulation
- Mental Status
- Priority
What are facies?
Obvious signs leading to quick or obvious diagnosis.
Describe the following body habitus terms:
- ectomorph
- mesomorph
- endomorph
- Ectomorph: lean, undernourished
- Mesomorph: well developed, athletic
- Endomorph: overdeveloped, obese
What 2 ways should pupillary reaction be checked?
Direct and consensual
What part of the stethoscope should be used for listening to the heart?
Both
What shape are alveoli?
Polyhedral
About how many alveoli does a person have?
300 million
Which type of alveolar cells secrete surfactant?
Type II
What is the function of type I alveolar cells?
structure
What is the surface area of our alveoli if spread out?
100 meters squared with about 80ml of blood spread out over it
How many divisions in the bronchial tree
about 22
What is lung parenchyma
any form of lung tissue including bronchiles, bronchi, blood vessels, interstitium and alveoli
What is the narrowest part of a pediatric airway?
Cricoid cartilage
What are some differences of the pediatric airway?
- Palate has more soft tissue
- Larynx is more superior and anterior
- Epiglottis rounder and floppier
What is the approximate % of the following components in sea level atmospheric air?
- Nitrogen
- Oxygen
- C02
- Water
Nitrogen: 78+%
Oxygen: 21%
CO2: 0.04%
Water: 0.5%
What are the 3 ways CO2 is transported from the cells back to the lungs?
Bicarbonate: 70%
Hemoglobin: 23%
Plasma: 7%
What is lung compliance?
The ease with which the chest expands.
What is Vital Capacity?
Inspiratory reserve + Tidal Volume + expiratory reserve
What is Minute Respiratory Volume?
the amount of gas moved in and out of the respiratory track in 1 minute.
What is Minute Alveolar Volume?
The amount of gas that reaches the alveoli for gas exchange in one minute
Where is respiratory rate typically controlled?
Medulla Oblongata. The Pons is also involved, as well as chemoreceptors in central and peripheral locations.
Name 2 antibiotics used to treat pneumonia.
Erythromycin, Levofloxacin
Describe what carpopedal spasms are and why they occur.
As a result of the body being too alkaline, the ca++ balance gets off, disrupting the membrane potential of the musculoskeltal system, causing too many action potentials, and therefore tetany. This causes the hands and feet will cramp into an abnormal position
Define Hypothesis
A question, or supposition that can be tested
Define Theory
well substantiated explanation, based on body of facts that have been repeatedly confirmed through observation and experiment.
Explain the difference between validity and external validity
Validity: internal conclusions are true
External Validity: conclusions are generalizeable beyond the specific study.
What is the difference between accuracy and precision?
Accuracy is “correctness” although there may be systematic errors
*Precision is reproducible (picture a tight grouping, but not at the bullsye)
What is the difference between sensitivity and specificity?
- Sensitivity: finding something when it’s there
* Specificity: not finding something when it isn’t there
What is p-value?
probablility that observations are due to chance
p<0.05 is considered arbitrary
What is standard deviation and what are the levels?
Measure of dispersion around the mean. 1 sigma: 68.3% 2 sigma: 95.5% 3 sigma: 99.7 4 sigma: 99.99
2 sigma most common
