glucose homeostasis

Question 1

On admission sam was prescribed insulin to lower his BGL. Describe five actions of insulin

Answer 1

• accelerates facilitated diffusion of glucose into cells
• accelerates the conversion of glucose into glycogen (glycogenesis)
• increases the synthesis of proteins and fatty aid (lipogenesis)
• slows the conversion of glucose from glycerol (glycogenolysis)
• slows the formation of glucose from glycerol amino acids and lactic acid (gluconeogenesis)

Question 2

In view of his high level of blood glucose in the blood would you expect any change in the composition and volume of his urine? Explain your answer

Answer 2

• sams blood glucose exceeds the renal threshold for glucose, which is 9mmol/L this means that the capacity of his renal tubules to reabsorb glucose has been exceeded and glucose will be lost in urine.
• water will follow by osmosis so the volume of sams urine will increase.

Question 3

Explain the relationship between blood osmolality and thirst. Explain what you think is happening to the osmolality in his blood. do you think sam will be more or less thirsty in this situation

Answer 3

• sam will have increase blood osmolality because he has an excessive urine output which will cause dehydration
• the thirst centre in the hypothalamus will activate thus sam will want to drink more

Question 4

Name and describe two metabolic reactions that will provide glucose for cells

Answer 4

• glycogenolysis, the breakdown of glycogen to form glucose

- gluconeogenesis- the synthesis of glucose from amino acids glycerol and lactic acid.

Question 5

The metabolic reaction of lipolysis will also occur to provide glycerol for the creation of glucose. this fat breakdown has resulted in an overproduction of ketone bodies, leading to the diagnosis of ketoacidosis. explain what this means in regard to the blood pH and H+ concentration

Answer 5

• blood pH will be lowered in response to increased concentration of H+

Question 6

Explain how the respiratory system will help to compensate and return his blood pH into the normal range. state the location and type of receptors in his body that will detect the change. name the control centre and the response of the effector. explain how this will help restore the blood pH

Answer 6

• sams blood gas indicates a metabolic acidosis, chemoreceptors in his aortic arch and carotid sinus will send impulses to the respiratory centre in the medulla oblongata and pons the respiratory centre will send impulses to increase the rate and depth of breathing
• the increased respiratory rate and depth reduces the level of CO2 in the blood which reduces the level of H+ and raises blood pH

Question 7

Name the hormone that is produced in response to low BGL and describe two ways this hormone will increase BGL

Answer 7

Glucagon stimulates

• liver cells to convert stored glycogen into glucose (glycogenolysis)
• formation of glucose from glycerol amino acids and lactic acid (gluconeogenesis)

Question 8

Name three hormones that would help to restore sams blood glucose level. Explain what causes the release of each and describe one action for each hormone to restore glucose.

Answer 8

• adrenaline release is stimulated by the sympathetic nervous system it causes rapid glycogenolysis
• cortisol is released in a stress situation under the influence of ACTH and causes gluconeogenesis by the liver the low BGL would be detected by the hypothalamus which stimulates the anterior pituitary to release growth hormone stimulating glycogenolysis in the liver and lipolysis
• thyroxine stimulates protein synthesis and use of glucose and fatty acid to produce ATP