Sec 4 Biology Homeostasis & Response topical questions

Define homeostasis and name the body system that coordinates rapid responses.

Name the hormone that lowers blood glucose, the cells that produce it, and the organ where it acts.

List, in the correct order, the five parts of a reflex arc from stimulus to response.

State what happens to the pupil in bright light, and name the iris muscles that contract.

Name (a) the gland that releases ADH, (b) the two hormones that together regulate blood glucose, and (c) the brain region that monitors blood temperature.

Using blood glucose regulation as an example, describe the stages of a negative feedback loop.

Explain two responses of the body that increase heat loss on a hot day.

After a meal a student’s blood glucose rises from 90 mg per 100 cm³ to 150 mg per 100 cm³. Calculate the percentage increase, and state and explain the hormonal response.

Explain how the lens focuses light from a nearby object onto the retina.

A person’s urine output falls from 1500 cm³ per day when well hydrated to 450 cm³ per day after a day of heavy sweating with little to drink. Calculate the percentage decrease and explain the ADH mechanism behind it.

Explain how vasoconstriction and shivering each help raise a falling core temperature, and name the control centre directing them.

Compare nervous coordination with hormonal coordination in terms of speed, transport and duration of effect.

Describe fully how the body responds when the core temperature falls below the set point on a cold day, naming the receptors, the control centre and two corrective mechanisms.

A hiker drinks nothing for six hours in the sun. Describe how ADH changes her urine, naming the hormone’s source and the kidney structure it acts on, and explain why this response is an example of osmoregulation.

Explain why type 2 diabetes develops, state two risk factors, and describe two ways a patient can manage the condition without insulin injections.

A pupil’s diameter decreases from 5.0 mm in dim light to 2.0 mm in bright light. Calculate the percentage constriction and describe the muscle actions and nervous pathway that produce it.

Plan an investigation into how light intensity affects pupil diameter. State how the pupil is measured, how light intensity is varied and standardised, which precautions are taken, and the expected result.

A described graph shows a student’s blood glucose rising from 90 to 150 mg per 100 cm³ within 20 minutes of a sugary drink, then falling to 95 mg per 100 cm³ by 80 minutes. Calculate the percentage rise and the percentage fall from the peak, and explain the shape of the graph using the hormones involved.