Top answers

Describe the movement of ions, and changes in potential, across the nerve cell membrane during depolarisation and repolarisation.

During depolarisation, sodium ions move into the cell, resulting in the membrane potential rising from -70 millivolts (mV) to +40mV.During repolarisation, potassium ions move out of the cell, and the membran...
WP
Answered by William P. • Biology tutor
4537 Views

What are the advantages of saltatory conduction?

· The myelin sheath means that action potentials can occur only at the gaps between the Schwann cells that make up the myelin sheath.· Effectively the action potential jumps from one node of Ranvier to the n...
NS
Answered by Natalia S. • Biology tutor
10117 Views

What is saltatory conduction?

· Myelin sheath is an insulating layer of fatty material, composed of Schwann cells wrapped tightly around the neurone.· Sodium and potassium ions cannot diffuse through this fatty layer.· In between the Sch...
NS
Answered by Natalia S. • Biology tutor
7565 Views

How does smoking affect gas exchange in the lungs?

Firstly, think of what you already know about the structure of the lungs and how that makes them so effective at their job. (Elasticity, large surface area for gas exchange, high gradient and short diffusion...
EE
Answered by Esther E. • Biology tutor
6836 Views

Explain how a rise in blood pressure results in a decrease in the rate of heartbeat.

Baroreceptors detect the rise in blood pressure in the aorta, they send impulses to the cardiovascular centre. Then, impulses are sent via parasympathetic nerves to the SAN. This triggers the release of ACh,...
KS
12749 Views