This free quiz has 22 multiple choice questions on neuronal and hormonal communication, all taken from OCR A Level Biology A exam papers. It marks itself, so you get your score as soon as you finish.
What the quiz covers (OCR A spec 5.1.3 and 5.1.4)
Sensory receptors as transducers, including the Pacinian corpuscle
Sensory, relay and motor neurones
Resting potential, action potentials and repolarisation
Structure and function of cholinergic synapses
Excitatory and inhibitory neurotransmitters and summation
Endocrine communication and the adrenal glands
The pancreas, insulin and glucagon in blood glucose control
Diabetes and its treatment
How to use it
Sketch an action potential graph with labelled axes and a simple synapse diagram before you begin, then note which ions move and in which direction at each stage. For the hormone questions, jot down which gland or tissue makes each hormone and where it acts.
Where students lose marks (from OCR examiners' reports and mark schemes)
Each point below is followed by wording that gained marks.
Generator versus action potentials: Many students did not separate the generator potential, caused by sodium ions entering through ligand-gated channels, from the all-or-nothing action potential that needs voltage-gated channels. A common error was saying no sodium ions enter or no depolarisation occurs, or writing about a 'signal' or 'message'.
✔ Gains credit: Explaining that fewer sodium ions enter so the axon membrane is not depolarised enough to open voltage-gated sodium channels, the membrane stays near resting potential and no action potentials pass along sensory neurones to the CNS.
Say what a transducer converts: Weaker answers stated a textbook definition of a transducer without applying it to the receptor in the question, or wrote vaguely about 'sensory information' or 'pain'.
✔ Gains credit: Naming the form of stimulus energy (for example mechanical, chemical or pressure) and stating that the receptor converts it into electrical impulses or action potentials.
Conduction in unmyelinated axons: Many students simply said impulses cannot jump from node to node, which only restates what saltatory conduction is. Others did not link damaged myelin to lost saltatory conduction.
✔ Gains credit: No nodes of Ranvier, so local currents are shorter and the whole length of the axon membrane must be depolarised; for damaged myelin, fewer or damaged Schwann cells so saltatory conduction cannot occur.
Name the muscle membrane that depolarises: Many answers on the neuromuscular junction mentioned 'less depolarisation' or 'less calcium' without saying where. Students also confused the frequency with the speed of impulses, release with production of acetylcholine, and the sarcolemma with a postsynaptic neurone.
✔ Gains credit: Fewer sodium ions entering the muscle cell, less depolarisation of the sarcolemma or T-tubules, and fewer calcium ions released from the sarcoplasmic reticulum, with fewer impulses arriving and less acetylcholine released.
Adrenal cortex and medulla hormones: Less successful answers mixed up the effects of adrenal hormones, giving cortisol a role in ion regulation or blaming both hormones for every symptom. Some mentioned the sympathetic nervous system without linking it to the fight or flight response.
✔ Gains credit: Cortisol (from the cortex) regulates carbohydrate metabolism, aldosterone regulates ion concentrations and so blood pressure, and adrenaline comes from the medulla, which ACTH does not control.
Exocrine means secreting into ducts: Some students wrote that glands 'excrete' hormones or release them inside the cell, and others described pancreatic digestive enzymes as becoming active outside cells instead of saying where they go.
✔ Gains credit: Endocrine glands secrete hormones directly into the blood (they are ductless), whereas the exocrine pancreas releases digestive enzymes into ducts.
Be precise about type 2 diabetes: Explanations often said the 'body' no longer responds to insulin, and management answers such as 'eat a healthy diet' did not mention carbohydrates.
✔ Gains credit: Insulin is still produced but target cells (such as liver cells) respond less, for example because of fewer or damaged insulin receptors; management by a low carbohydrate or low sugar diet, exercise and weight control.
Keep practising
Go on to the Plant and Animal Responses quiz, the Homeostasis and Excretion quiz or the Biological Membranes quiz, or browse all our OCR A Level Biology quizzes. Our OCR A masterclasses (Year 12 on Wednesdays at 5.15pm, Year 13 on Tuesdays at 6.30pm) work through real exam questions on one topic each week.