Homeostasis + Coordination & Response

The graphs show how four different conditions in the body may change with time. In which graph is/are the condition(s) being controlled by negative feedback?

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Which response is not due to homeostasis?

• enlargement of iris

• increase in glucose production when blood glucose level is low

• increase in permeability of collecting duct of kidney tubules

• shivering in cold weather

Which statement about voluntary actions is not true?

• Relay neurones are always involved in voluntary actions.

• Voluntary actions always involve transmission of nerve impulses to or from the spinal cord.

• Voluntary actions are always coordinated by the brain.

• Voluntary actions may not involve sensory neurons.

A finger that touches a hot object is quickly taken away from the source of heat. What is the role of relay neurons in this response?

• to carry nerve impulses within the spinal cord

• to generate nerve impulses in the receptors of the finger

• to link the sense organs to the sensory neurones

• to pass nerve impulses to the effectors

The diagram shows the cross-section of the spinal cord of a rat.

In which scenario will the rat still be able to move?

• spinal cord cut at Y and electrical stimulation applied at P

• spinal cord cut at Y and electrical stimulation applied at R

• spinal cord cut at Z and electrical stimulation applied at Q

• spinal cord cut at Z and electrical stimulation applied at S

Which changes take place in the iris of the eye when a person moves quickly from darkness into bright light?

• A

• B

• C

• D

Which part of the eye causes the greatest refraction of light?

• aqueous humour

• cornea

• lens

• vitreous humour

Paul looked out of the classroom window of the class across the corridor to look at Sam who was waiting for him. He looked at the watch on his wrist to check the time before giving his teacher a stare, impatiently waiting for him to end the lesson.

Which diagram shows the sequence of the changes in the shape of the lens of his eyes?

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Which structure in the eye is not correctly linked to its function?

• choroid - provide oxygen and nutrients to the eyeball

• fovea - region where optic nerve leaves the eye

• rectus muscle - control movement of eyeball

• sclera - protects eyeball from mechanical damage

What substance is the urine of a person suffering from diabetes mellitus likely to contain?

• amino acids

• fatty acids

• glucose

• proteins