Physiology of thirst
Download as PPT, PDF
9 likes3,398 views
The document discusses the four main stimuli that cause thirst: hypertonicity, hypovolaemia, hypotension, and angiotensin II. Hypertonicity refers to a higher concentration of solutes outside cells than inside, causing cellular dehydration. Hypovolaemia is a decreased blood volume and plasma volume. Hypotension means low blood pressure. Angiotensin II is released by the kidneys in response to renal hypotension. Osmoreceptors in the hypothalamus detect hypertonicity and hypovolaemia. Low pressure baroreceptors in veins and arteries detect hypotension. High pressure baroreceptors and angiotensin II also contribute to the feeling of thirst
Physiology of thirst
- 14. Under normal conditions, most water intake is due NOT to thirst but to social factors cultural factors (e.g. drinking with meals or at work breaks, water in food)
- 16. How do we feel thirsty?
- 17. There are 4 stimuli for thirst
- 18. Hypertonicity
- 22. I. Hypertonicity Higher concentration of solutes outside the cell than inside the cell > cellular dehydration Causes: High sodium diet
- 23. II. Hypovolaemia Decreased blood volume; more specifically, decrease in volume of blood plasma (ICF volume is decreased) Causes: Haemorrhage
- 24. III. Hypotension = low blood pressure Causes: Pregnancy Heart problems Endocrine problems Haemorrhage Dehydration .. etc
- 27. Hypertonicity Hypovolaemia Osmorec eptors in the hypothala mus Low pressure baroreceptor s in the great veins and right atrium
- 28. Hypertonicity Hypovolaemia Hypotension Osmorec eptors in the hypothala mus Low pressure baroreceptor s in the great veins and right atrium High pressure baroreceptor s in carotid sinus & aorta
- 29. Hypertonicity Hypovolaemia Hypotension Angiotensin II Osmorec eptors in the hypothala mus Low pressure baroreceptor s in the great veins and right atrium High pressure baroreceptor s in carotid sinus & aorta consequent to the release of renin by the kidney (in response to renal hypotension)
- 30. In Summary ..
- 33. Thank You Any Question? Thank You..