Lab 10 Q&A

Name the components of an EKG wave

Name the components of an EKG wave

• P wave = atrial depolarization that precedes atrial systole.
• QRS complex = ventricular depolarization
  • (atrial repolarization occurs during this time, but is obliterated by the greater QRS complex)
• T wave = ventricular repolarization that occurs just before the end of ventricular systole.
• P-R interval = time between the beginning of the P wave and the beginning of the QRS complex.
  • Typically about 0.15 seconds, this reflects atrial depolarization (the P wave) and the time delay caused by the AV node for the electrical impulse to travel from the atria to the ventricles (represented by the flat area of the P-R interval.
• Q-T interval = time from the beginning of the Q wave to the end of the T wave.
  • This normally lasts less than 0.38 seconds and approximately corresponds to the time of ventricular contraction.

How does an action potential travel through the heart?

1. SA node - generates spontaneous AP
2. Internodal tracts
3. AV node - delays AP to allow for ventricular filling.
4. Bundle of His
5. Right bundle and left posterior bundle
6. Purkinje Fibers

How does an EKG change with increased HR?

Pulse Pressure

Mean Arterial Pressure

Cardiac Cycle

Respiratory Physiology Lab 11

Lab Purpose

To allow students to experiment with principles of respiration, specifically the various types of pulmonary volumes, assessment of these volumes and ventilatory drive.

Lab objectives

1. Explain the forces that cause air to move in and out of the lungs.
2. Describe in writing or orally the lung volumes and capacities and how each one is determined.
3. Describe FVC relative to VC, FEV1 and FEV3. Be able to describe the effect an obstructive lung disease such as asthma would have on each of these.
4. Understand the effect that PaO2, PaCO2 and arterial pH have on ventilatory drive.

Lab Safety

Do not share mouth pieces.

Clean nose plugs with alcohol wipe.

If the software asks you to activate it just choose the "do later" option.

Using the spirometer

Procedure Hacks

• No real shortcuts for this lab. Gathering data only takes a few minutes so everyone should do it.
• Completely read the instructions for each procedure before starting the experiment so you don't have to do things twice, thrice, or fice?
• Wait for the long LOUD beep, ignore the little ones.

Core Principles

Mechanics of Ventilation

Why does that work?

Why does that work?

Pneumothorax

Pulmonary Volumes

FVC,  FEV1 & FEV3

• FVC - forced vital capacity.
• FEV1 - forced expiratory volume in one second.
• FEV3 - forced expiratory volume in three seconds.
• Normal FEV1/FVC ratio: ~0.8
  • High: Restrictive
  • Low (<0.7): Obstructive

Ventilatory Drive

• Controlled by chemoreceptors
  • Peripheral -carotid bodies
  • Central - medulla

Hyperventilation