Chapter 1 Practice Paper: Homeostasis, Co-ordination and Response in Humans — question paper

Section A: Multiple-choice questions[10 marks]

Choose the one correct answer for each question.

1. 1

   Blood glucose rises above the set point after a meal. In the negative feedback loop that follows, the corrective mechanism is

   1. Aglucagon converting glycogen to glucose
   2. Binsulin causing the liver to store glucose as glycogen
   3. CADH increasing water reabsorption
   4. Dshivering releasing heat from respiration
   ( )
2. 2

   In cold conditions the skin arterioles

   1. Adilate so more blood reaches the skin surface
   2. Bconstrict so less heat is lost by radiation
   3. Crelease sweat directly into the capillaries
   4. Dremain unchanged because only the muscles respond
   ( )
3. 3

   Which gland secretes both insulin and glucagon?

   1. Athe liver
   2. Bthe pituitary gland
   3. Cthe islets of Langerhans in the pancreas
   4. Dthe thyroid gland
   ( )
4. 4

   Which row correctly matches the light level to the iris muscle action and pupil response?

   1. Abright light: radial muscles contract → pupil dilates
   2. Bdim light: circular muscles contract → pupil constricts
   3. Cbright light: circular muscles contract → pupil constricts
   4. Ddim light: radial muscles relax → pupil constricts
   ( )
5. 5

   A dehydrated athlete produces small volumes of concentrated urine. The hormone responsible and its action are

   1. AADH — makes the collecting duct more permeable so more water is reabsorbed
   2. Binsulin — converts glucose to glycogen
   3. Cglucagon — releases glucose from glycogen
   4. Dadrenaline — increases the heart rate
   ( )

Section B: Structured questions[20 marks]

Answer all questions in the spaces provided.

1. 1

   A runner finishes a marathon on a hot afternoon. Her core temperature has risen above 37 °C and she is drenched in sweat.

   1. (a)

      Name the organ that monitors her blood temperature and the body parts that detect the external heat.

      [2]
   2. (b)

      Describe two mechanisms that help her lose heat, and explain how each works.

      [3]
   3. (c)

      She loses 1.2 dm³ of sweat during the 90-minute race. Calculate her mean rate of sweat loss in dm³ per hour.

      rate =dm³/h[1]
2. 2

   After a sugary drink, a student’s blood glucose rises from 90 mg per 100 cm³ to 150 mg per 100 cm³. Thirty minutes later it has returned to 95 mg per 100 cm³.

   1. (a)

      Calculate the percentage increase in blood glucose after the drink.

      increase =%[2]
   2. (b)

      Name the hormone released in response, the cells that release it, and state what the liver does under its influence.

      [3]
   3. (c)

      Explain why this sequence is an example of negative feedback.

      [2]
3. 3

   A bright torch is shone into a person’s left eye, and both pupils become visibly narrower within a second.

   1. (a)

      Name the receptors that detect the light and the nerve that carries the impulses towards the brain.

      [2]
   2. (b)

      Describe the muscle actions in the iris that narrow the pupil.

      [2]
   3. (c)

      The pupil’s diameter falls from 5.0 mm in dim light to 2.0 mm in bright light. Calculate the percentage constriction, and state one benefit of this reflex.

      [3]