Homeostasis

Question 1

what plays/ does not play a role in homeostatic balance?

Answer 1

-balance maintained by collective action of urinary, respiratory, digestive, endocrine, nervous, cardiovascular, and lymphatic systems

Question 2

dehydration role in homeostasis and when ADH is secreted

Answer 2

• dehydration is when water loss is greater than gain. The decrease in volume increases osmolarity of fluids and stimulates the thirst center in the hypothalamus
• in turn raises ADH (anti diuretic hormone) secretion so water will be retained (hypothalamus is signaled to release ADH to retain water)

Question 3

where is most water in our body found?

Answer 3

• intercellular fluid (inside cells): 65%

- 2/3 of body fluid

Question 4

where does most of the water in our body come from and how is most of it lost?

Answer 4

• comes mostly from ingestion of liquids and food (2300mL/day), and metabolic synthesis of water during cellular respiration and dehydration synthesis (200mL/day)
• mostly lost from kidneys (urination) (1500mL/day), evaporation from skin (sweat) (600mL/day), exhalation from lungs (300mL/day), and feces (100mL/day)

Question 5

what percentage of our body composition does water account for?

Answer 5

55% females; 60% males

Question 6

what governs fluid intake?

Answer 6

thirst center in hypothalamus increases thirst and water intake

Question 7

what does the ADH hormone produced in the hypothalamus promote?

Answer 7

• regulates water loss
• increases water permeability in urine
• produces concentrated urine

Question 8

what are some long term inhibitions of thirst?

Answer 8

• decreased flow of saliva -> dry mouth and pharynx
• increased blood osmolarity -> stimulates osmoreceptors in hypothalamus
• decreased blood volume -> decreased blood pressure -> increased renin release in kidneys -> increased angiotensin II formation

Question 9

bicarbonate buffer system chemical equation

Answer 9

CO2 + H2O H2CO3 HCO3- + H+

• can do right winded reaction to lower pH by releasing H+
• can do left winded reaction to raise pH by binding H+

Question 10

what are some major chemical buffer systems of the body?

Answer 10

• protein buffer system
• bicarbonate buffer system
• phosphate buffer system

Question 11

what is the normal pH level for the body and tissue fluid?

Answer 11

7.35- 7.45

Question 12

respiratory acidosis/ alkalosis and was causes these

Answer 12

• results from changes in partial pressure of CO2 in systemic arterial blood
• acidosis= abnormally high PCO2 in systemic arterial blood; inadequate exhalation of CO2; caused by any condition that decreases mvmt of CO2 out of lungs (emphysema, pulmonary edema, etc); treatment is ventilation
• alkalosis= abnormally low PCO2 in systemic arterial blood; caused by hyperventilation due to oxygen deficiency from high altitude, pulmonary disease, stroke, severe anxiety; treatment is breathing into paper bag

Question 13

four general functions of electrolytes

Answer 13

• control osmosis of water between body fluid compartments
• help maintain acid- base balance
• carry electrical current (brain and heart function)
• serve as cofactors (need electrolytes to get to threshold for signals to move muscles)

Question 14

metabolic acidosis/ alkalosis and was causes these

Answer 14

• kidneys
• Results from changes in bicarbonate (HCO3-) concentration
• acidosis= abnormally low HCO3 in systemic arterial blood; caused by severe diarrhea, renal disfunction, accumulation of acid other than carbonic acid (ketosis), failure of kidneys to excrete H+ from metabolism of dietary proteins; hyperventilation can help, IV of sodium bicarbonate can correct
• alkalosis= Abnormally high HCO3- in systemic arterial blood; caused by non respiratory loss of acids (vomiting stomach acid), excessive intake of alkaline drugs (antacids), use of certain diuretics, severe dehydration; hyperventilation can help, fluid solutions to correct Cl-, K+ and other electrolyte deficiencies

Question 15

respiratory acidosis/ alkalosis and was causes these

Answer 15

• lungs
• results from changes in partial pressure of CO2 in systemic arterial blood
• acidosis= abnormally high PCO2 in systemic arterial blood; inadequate exhalation of CO2; caused by any condition that decreases mvmt of CO2 out of lungs (emphysema, pulmonary edema, etc); treatment is ventilation
• alkalosis= abnormally low PCO2 in systemic arterial blood; caused by hyperventilation due to oxygen deficiency from high altitude, pulmonary disease, stroke, severe anxiety; treatment is breathing into paper bag