Osmoregulation & Glucoregulation

Osmoregulation & Glucoregulation

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Multiple Choice

Loss of too much water from the body.

• Diarrhea

• Dehydration

• Hydration

• Sweating

Multiple Choice

Which does not cause dehydration?

• Heavy sweating

• Low water intake

• Respiration

• Breathing dry air

Multiple Choice

When the salt concentration of the blood is too high, the body contains _____.

• too little water

• too much water

• just enough water

• no water

Multiple Choice

High salt concentration stimulates the receptors in the _____.

• brain

• hypothalamus

• kidneys

• pituitary

Multiple Choice

The kidneys reabsorb less water so ____.

• small quantities of diluted urine is produced

• small quantities of concentrated urine is produced

• large quantities of diluted urine is produced

• large quantities of concentrated water is produced

Analysing Urine

• Changes in the colour, clarity, pH and the presence of certain substances in urine can help doctors diagnose medical conditions:

Analysing Urine

• Protein or red blood cells in urine can indicate kidney damage or disease, as these substances would not normally filter through the glomerulus.

Analysing Urine

• Glucose in urine is often an indication of diabetes. A person with diabetes will have a high level of glucose in the blood.

Multiple Choice

Which patient would have urine sample containing glucose?

• Football player kicked in the kidney

• Marathon runner

• Person who has drunk a lot of fluid

• A person with diabetes

Multiple Choice

Which patient would have a very dark urine sample?

• Football player kicked in the kidney

• Marathon runner

• Person who has drunk a lot of fluid

• A person with diabetes

Multiple Choice

Which patient would have a very light colored urine sample?

• Football player kicked in the kidney

• Marathon runner

• Person who has drunk a lot of fluid

• A person with diabetes

Multiple Choice

Which patient would have a urine sample containing protein?

• Football player kicked in the kidney

• Marathon runner

• Person who has drunk a lot of fluid

• A person with diabetes

Glucoregulation

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Multiple Choice

Insulin leads to

• gluconeogenesis

• increased facilitated diffusion of glucose into hepatocytes

• glycogenolysis

• increased protein kinase activity

Multiple Choice

Glycogenesis

• Converting glycogen to glucose

• First stage of aerobic and anaerobic respiration

• Synthesising glycogen from glucose

• Synthesising glucose from non-carbohydrate sources

Multiple Choice

Glucagon is

• a neurotransmitter

• released in response to high blood sugar

• secreted by α-cells

• secreted by β- cells

Multiple Choice

What is glycogen?

• polymer of α-glucose

• polymer of β-glucose

• polymer of amino acids

• polymer of glycerol

Multiple Choice

Insulin converts glucose to

• glucagon

• glycogen

• glycerol

• glucose

What affects the level of blood glucose?

• Eating causes blood glucose levels to rise.

• Vigorous exercise causes blood glucose levels to fall.

Controlling blood glucose

• Between meals, blood glucose levels are topped up from stored deposits in the liver and muscles.

• After a meal, blood glucose rises but quickly returns to normal. Where does the excess go? Why not leave it in the blood?

Controlling blood glucose

• Excess glucose makes the blood plasma and tissue fluid around cells too concentrated. This can severely damage cells, for example, causing crenation in red blood cells.

• Crenation - formation of abnormal notched surfaces on cells as a result of water loss through osmosis.

Controlling blood glucose

• However, low blood sugar levels can be equally as dangerous, as it can make cells swell up and burst. This is called lysis.

• Hemolysis - destruction of red blood cells.

The pancreas and blood glucose

• Blood glucose levels are monitored and controlled by the pancreas.

• The pancreas produces and releases different hormones depending on the blood glucose level.

The pancreas and blood glucose

• At the pancreas, the presence of an excess of blood glucose is detected in patches of cells known as the islets of Langerhans.

• The islets of Langerhans contain two types of cell, alpha (α) cells and beta (β) cells

Multiple Choice

TRUE or FALSE: Vigorous exercise causes blood glucose levels to rise.

• TRUE

• FALSE

Multiple Choice

TRUE or FALSE: Liver and muscles store glucose.

• TRUE

• FALSE

Multiple Choice

TRUE or FALSE: Excess glucose makes the blood plasma and tissue fluid around cells too concentrated.

• TRUE

• FALSE

Multiple Choice

TRUE or FALSE: Glucagon is released when blood glucose levels are low.

• TRUE

• FALSE

Raised blood glucose level -

• the beta (β) cells are stimulated. 

• they secrete the hormone insulin into the capillary network

• insulin stimulates the uptake of glucose by cells all over the body, but especially by the liver and the skeletal muscle fibres.

• insulin triggers the conversion of glucose to glycogen (glycogenesis) and of glucose to fatty acids and fats (lipogenesis) in liver cells.

• insulin also promotes the deposition of fat around the body.

• as the blood glucose level reverts to normal this is detected in the islets of Langerhans, and the beta cells respond by stopping insulin secretion.

Blood glucose level falls below normal -

• the alpha (α)cells are stimulated.

• they secrete a hormone called glucagon.

• glucagon activates the enzymes that convert glycogen and amino acids to glucose (gluconeogenesis).

• glucagon also reduces the rate of respiration.

• as the blood glucose level reverts to normal, glucagon production ceases.

Open Ended

Summarize how does negative feedback control blood glucose.

The Disease of Diabetes

• Hypoglycaemia, in which our blood glucose falls below 2.0 mM/L.

• If this is not quickly reversed, we may faint.

• If the body, and particularly the brain, continue to be deprived of adequate glucose levels, convulsions and coma follow.

The Disease of Diabetes

• Hyperglycemia, in which an abnormally high concentration of blood glucose occurs.

• Lowers the water potential of the blood plasma, water is drawn immediately from the cells and tissue fluid by osmosis, back into the blood.

• Water is excreted by the kidney to maintain the correct concentration of blood.

Diabetes is the name for a group of diseases in which the body fails to regulate blood glucose levels.

Dip-sticks and biosensors for quantitative measurements of glucose

Open Ended

Compare and contrast hypoglycemia and hyperglycemia.

Open Ended

Compare and contrast Type 1 diabetes and Type 2 diabetes.

Poll

I am confident that I have understood the concepts of osmoregulation and glucoregulation.

• Strongly agree

• Agree

• Neither agree or disagree

• Disagree

• Strongly disagree

ASSIGNMENT: Read and study "The role of Cyclic AMP as a Second Messenger"