Biology A2, F2144 module 1: communication & homeostasis

The difference between negative and positive feedback is:

• One is always good for the body and one is always bad

• Negative feedback uses neurones and positive uses hormones

• Negative reverses a change away from optimum. Positive enhances it.

• Negative feedback is part of the autonomic nervous system. Positive feedback is part of the somatic

Which is the correct description of a motor neurone?

• Small cell body at receptor, long dendron but short axon with numerous dendrites. Myelinated.

• large cell body at Central Nervous System, long dendron with dendrites going to effectors. Non myelinated

• large cell body at receptor, long dendrite, short axon but no dendron . Myelinated.

• Large cell body at Central Nervous System and a long axon with dendrites. Myelinated.

Which is the correct shape of graph for the generation and conduction of an action potential?

In the conduction of an action potential, what happens after Na+ ion channels close ?

• the sodium/potassium pump begins pumping 2K+ into the cell and 2Na+ out.

• the cell repolarises.

• K+ ion channels open.

• The cell depolarises

Local Currents are...

• When ions diffuse into the cell and gather in a high conc. at the point at which they diffused in, causing them to diffuse to an area of low conc. further down the cell.

• The way in which an action potential appears to "jump" between the nodes of ranvier along a myelinated neurone.

• the slow, smooth, linear flow of an action potential in a non-myelinated neurone due to the high concentrations of ions diffusing in through voltage gated channels and diffusing down the neurone.

• Where several action potentials join together to make one, larger one.

What type of ion channels are present on the synaptic knob of a presynaptic neurone, that trigger the release of neurotransmitter?

• Sodium/potassium pump

• acetyl choline receptors

• sodium ion channel

• calcium ion channel

What is the name of the neurotransmitter in a cholinergic synapse and the enzyme that breaks it down?

• Nor-adrenaline and Adrenelase

• choline and cholinase

• acetyl choline and acetylcholinesterase

• acetate and acetatedecarboxylase

cAMP is a...

• hormone

• chemical

• enzyme

• second messenger

Which chemical reaction does insulin trigger in hepatocytes?

• glycolysis

• glycogenesis

• gluconeogenesis

• glycogenolysis

Which of the following is NOT a risk factor for type 2 diabetes mellitus?

• Family History

• not being able to produce enough insulin

• obesity

• being of asian/afro-Caribbean origin

Which of these would lead to an impulse being sent down the vagus nerve?

• rise in blood pressure

• rise in activity in the limbs

• fall in blood pH

• Adrenaline being released into the blood