HOMEOSTASIS (TUTORIAL)

What is meant by homeostasis?

• Control of glucose level in blood.

• Maintenance of a constant internal environment of

  a body.

• Maintenance of a constant internal and external environment.

• Control of body temperature during fever.

Which of the following is NOT a negative feedback

mechanism?

• Body temperature control.

• Uterine contraction

  during birth process.

• Control of blood glucose level.

• Control of blood pH.

The diagram below shows an outline of a feedback mechanism in homeostasis. Identify A, B, Process X and Y.

• A = control centre; B = receptor; process X = positive feedback; process Y = negative feedback

• A = control centre; B = effectors; process X = negative feedback; process Y = positive feedback

• A = receptor; B = effectors; process X = negative feedback; process Y = positive feedback

• A = receptor; B = control centre; process X = positive feedback; process Y = negative feedback

The two body systems that regulate homeostasis

are the…

• cardiovascular

  and respiratory systems.

• cardiovascular and urinary systems.

• cardiovascular and endocrine systems.

• nervous and endocrine systems.

If a response enhances the original stimulus, the mechanism is classified as a _________ feedback mechanism.

• neutral.

• polarized

• negative

• positive

What happens when beta cells of the pancreas release insulin into the blood?

• Blood glucose level rises to a set point and stimulates glucagon release.

• Body cells take up more glucose.

• The

  liver breakdowns glycogen to glucose.

• Alpha cells are stimulated to release glucose into the blood.

Which tubule has a U shape?

• Distal convoluted tubule.

• Proximal convoluted tubule.

• Loop of Henle.

• Collecting duct.

What is the mechanism for the filtration of blood within the nephron?

• The active transport of Na⁺ and glucose, followed by osmosis.

• Both active and passive secretion of ions, toxin and NH₃ into the tubule.

• High hydrostatic pressure of blood forcing water and small molecules out of the capillaries.

• A lower osmotic pressure in Bowman’s

  capsule compared to the osmotic pressure in the glomerulus.

Which

part of the vertebrate nephron consists of capillaries?

• Glomerulus

• Loop of Henle

• Distal

  tubule

• Bowman’s capsule

What substance is secreted by the proximal-tubule cells and prevents the pH of urine from becoming too acidic?

• Bicarbonate

• Salt

• Ammonia

• Glucose