Thermoregulation in dogs & pathophysiology of hyperthermia

1. Thermoregulation in dogs& pathophysiology of hyperthermia LanAnh , Warunwati , Suwanee 26 Jun. 2013

2. Importance of Thermoregulation Hot house effect • Stationary car • Enclosed area sunlight same as put them in oven + heat on

3. Importance of Thermoregulation alive cell function Multi. Body systems Respiratory Cardio vascular Endocrine Nervous Urinary Integumentary within optimal range maintain normal core body Temp.

4. Physiological Responses to Heat 1. Conduction

5. Physiological Responses to Heat 2. Convection

6. Physiological Responses to Heat 3. Radiation Natural process of body releasing heat into environment 4. Evaporation Most important if Environmental Temp. > 32° c

7. Physiological Responses to Heat Dog bring hot core body T. surface

8. Panting Inhalation through the nose Exhalation through the nose & mouth Increased rate Finally with the tongue

9. Panting Brachycephalic dogs heat dissipation by its anatomy

10. Panting Heavy panting - much energy utilized - water loss Dog try to get out of a hot car - Evaporation effective ( caused by high Temp. high Humid. ) ( ; conduction , convection , radiation )

11. Pathophysiology of Heat Stress If animals has not been acclimated to heat,humid. Forced to high heat Hypovolemia , dehydrate Forced for long time Vasoconstriction , Tissue dispersion  , Hypoxia etc. Hemorrhagic diarrhea , Arrhythmias , Renal failure Thermoregulation ineffective

12. Pathophysiology of Heat Stress dead cell disfunction Even as core body T. is returned to normal ** Vet. Should always be sought in case of prolonged heat exposure Whether or not there are obvious clinical signs

13. Predisposing factors that decrease heat dissipation Exogenous lack of acclimatization neuro-hormone poor ventilation 4 heat loss eff. high humidity evap. Eff. Water deprivation blood volume vasodilation

14. Predisposing factors that decrease heat dissipation Endogenous Brachycephalic ventilatory cap. Obesity , fat heat dissipation Cardiovascular disease cardiac output Neurologic./neuromuscular thermo-reg.  younger/older animals poor accli. Hair coat & color thicker , dark 

15. Thank you