4 cw 4 testy odruchy i cisnienie 12.03.2024

Cardiac Cycle in Dogs

  • Average duration of cardiac cycle phases (for a pulse rate of 75):

    • Isometric Contraction: 0.05 sec

    • Maximum Ejection: 0.12 sec

    • Reduced Ejection: 0.10 sec

    • Systole: 0.27 sec

    • Protodiastole: 0.02 sec

    • Isometric Relaxation: 0.05 sec

    • Rapid Filling: 0.06 sec

    • Diastasis: 0.29 sec

    • Atrial Systole: 0.11 sec

    • Diastole: 0.53 sec

    • Data sourced from Wiggers.

Equine Electrocardiographic Values (Horses)

  • Normal intervals and variations:

    • P-R Interval: 0.30 sec (0.20-0.42)

    • QRS Duration: 0.12 sec (0.08-0.17)

    • Q-T Interval: 0.54 sec (0.46-0.62)

    • Average Heart Rate: 38 bpm (24-50)

    • Limb leads used for measurements.

    • Variability noted in P wave forms (upright, inverted, diphasic, etc.)

Electrocardiogram Insights

  • Example from a Jersey cow:

    • P-R Interval: 0.22 sec

    • Characteristics of P, QRS, T waves described.

    • Led by Dr. L. L. Nangeroni.

Beagle ECG Reference Ranges

  • Heart Rate: 60-180 bpm

  • PR Interval: 0.06-0.14 sec

  • QRS Duration: 0.03-0.07 sec

  • QT Interval: 0.15-0.23 sec

  • Frontal Plane MEA: -30 to +120 degrees

  • T Wave Polarity: T waves typically variable.

Axonal Reflex

  • Described as extremely simple reflex arc:

    • Involves one neuron, with impulses transmitted in an antidromic manner.

    • Substance P's release noted to cause vasodilation and increased permeability.

    • Reflex arc operates without central nervous system mediation.

Ischemic Pain Mechanisms

  • Results from tissue hypoxia and acidosis:

    • Tissue hypoxia leads to cellular distress; acidosis exacerbates pain.

    • Acid-sensing ion channels (ASIC) are key in pain transmission.

  • Types of Ischemia:

    • Critical Limb Ischemia manifests as severe pain and skin damage.

    • Mesenteric Ischemia associated with atherosclerosis and other conditions.

Biological Functions of Substance P

  • Transmits noxious stimuli responses:

    • Involves action on various cells (keratinocytes, macrophages, endothelial cells).

Nociceptive Pain Pathway

  • Arises from nociceptor activation due to harmful stimuli.

    • Involves neurotransmitters like glutamate and substance P for signal transmission.

Orthostatic Hypotension

  • Observed commonly in older adults:

    • Describes a drop in arterial pressure upon standing, causing light-headedness.

    • Linked to low circulation blood volume and baroreceptor sensitivity loss due to arteriosclerosis.

  • Prevention of hydrostatic blood deposition includes increased vascular resistance and heart rate acceleration.

Measurement Techniques

  • Heart Rate Measurement:

    • Palpation on wrist/neck as easy but inaccurate; EKG provides precise but impractical measurement in sport settings.

    • The Ruffier Test involves exercise for continuous HR monitoring and is unsuitable for elderly or individuals with limb illnesses.

Blood Pressure Assessment

  • Systolic vs Diastolic Pressure:

    • Systolic: 120 mm Hg; Diastolic: 80 mm Hg; Pulse Pressure: 40 mm Hg.

    • Mean arterial pressure calculated with the formula: Diastolic + 1/3 of Pulse Pressure.

Korotkoff Sounds Phases in BP Measurement

  • Phase I: First faint sounds indicating systolic pressure.

  • Phase II: Softer sounds with a swishing quality.

  • Phase III: Sharper sounds returning to Phase I intensity.

  • Phase IV: Distinct muffling of sounds, transitioning to Phase V.

Venous Pressure Data

  • Recorded venous pressures in various animals including sheep, dogs, goats.

  • Average distances between vein valves in adults noted.

Conclusion

  • Topics integrated throughout the lesson span the efficiency of the circulatory system, methods of assessment, and physiological responses to various stimuli.