Blood Glucose and Diabetes

• Normal body temp for human females is between 36.5-37.3°C considering two standard deviations.
• Standard deviation indicates variability of a number around its mean.
• 95% of data is within 2 SDs, while 68% is within 1 SD.

Blood Glucose Control

• Blood glucose rises with carbohydrate consumption, and falls during exercise.
• The pancreas monitors blood glucose levels.
• Beta cells in the pancreas release insulin when glucose levels rise.
• Insulin promotes glucose uptake in the liver and muscles.
• Insulin causes glucose to condense into glycogen in the liver and muscle.
• Alpha cells in the pancreas release glucagon when glucose levels fall.
• Glucagon hydrolyzes glycogen into glucose in the liver, releasing glucose into the blood.
• Glucagon and insulin are antagonistic hormones.
• Control is achieved by negative feedback; as hormones restore glucose levels to the set point, hormone production decreases.

Type 1 and Type 2 Diabetes

• Type 1 diabetes typically starts in childhood, type 2 in adulthood/ later life.
• Type 1 stems from an autoimmune reaction where white blood cells destroy pancreas cells; type 2 involves a gradual decline in insulin production that is not due to an immune reaction.
• Type 1 patients eventually produce no insulin; type 2 patients produce less insulin and/or have insulin resistance.
• Type 1 risk factors are mostly genetic, while type 2 risk factors are largely obesity/environmental.
• Type 2 can be partially reversed with weight loss/diet changes.
• Type 1 requires insulin treatment, while type 2 can be managed with lifestyle changes, insulin-promoting drugs, or other treatments.

Body Temperature Variation

• Normal human body temperature varies over a 24-hour period.
• The difference between max and min temperature is about 1.35°C.
• The greatest rise in body temperature occurs from 9:30 to 10:00 am.
• During activity from 11:30 am to 6:30 pm, the normal variation is around 0.18°C.
• Individuals working night may have higher body temperatures at night when they are active.
• Body temperature is typically lower during rest and sleep because of a lower respiration rate and a lack of muscle activity.
• Circadian rhythm lowers body temperature, with a lower set point during sleep and thyroxine levels reduce at night, also lowering temperature due to the release of melatonin.

Heat Loss in Mammals

• Processes involved in heat loss from the body of a mammal.
• include vasodilation and respiration in brown adipose tissue.

Definition of Homeostasis

• Homeostasis best described as maintaining internal conditions within set limits.

Thermoregulation

• Thermoregulation involves the hypothalamus, skin thermoreceptors, and thyroxin.

Proximal Tubule

• The proximal tubule of the nephron reabsorbs molecules including nutrients, glucose, amino acids, vitamins, plasma proteins, and water.
• The proximal tubule is closely connected to a network of capillaries, reabsorbed materials re-enter the bloodstream.
• Over 90% of the water is reabsorbed and enters the bloodstream.
• Adaptations of cells lining the proximal kidney tubule for reabsorption include a large surface area with microvilli, a small lumen, and many mitochondria.
• Glucose is typically not found in urine, but it can be found in the urine of diabetic individuals.
• High glucose concentration in the blood and filtrate, as well as incomplete reabsorption in the proximal tubule, can lead to glucose in urine.
• Glucose is not reabsorbed in other areas of the nephron.

Loop of Henle and Aquaporins

• Water reabsorption in the kidney nephron is achieved by facilitated diffusion.
• Osmotic reabsorption requires a concentration gradient, a hypertonic medulla, and a high concentration of Na+ ions in the medulla.
• The Loop of Henle actively transport Na+ ions into the medulla by active transport from the ascending loop, creating a high Na+ concentration.
• ADH is released by the pituitary gland when blood is hypertonic or blood tonicity is above the set point which Increases the number and location of aquaporins.
• ADH increases water reabsorption into the medulla and bloodstream and lowers the urine volume.
• Aquaporins are membrane channel proteins for the movement of water by increasing in number and relocating to membranes.
• Aquaporins control water reabsorption from the collecting tubule.