Neurons

Question 1

What are Pacinian Corpsicle and what are their functions

Answer 1

Pacinian corpuscles are mechanoreceptors they detect mechanical stimuli for example pressure and vibration

They are found at the end of a sensory neuron called a sensory nerve ending. Sensory nerve ending is wrapped in tissue called lamellae .

When a Pacinian Corpuscles is stimulated the Lomeli are deformed and press on the sensory nerve ending. This causes deformation of stretched mediated sodium channels in the sensory neurons cell membrane. The sodium iron channels open and sodium ions diffused into the cell creating a generator potential if it reaches threshold it triggers an action potential.

Question 2

Describe a sensory neuron

Answer 2

Has short dendrites.

One long dendron (Carry receptor cell to cell body)

One short Axon (Carries impulses from cell body to CNS)

Question 3

Describe motor neuron

Answer 3

Many short dendrites (carry nerve impulses from the CNS to cell body)

One long axon (carry nerve impulses from cell body to effector cells)

Question 4

Describe relay neuron

Answer 4

Has many short dendrites (Carry impulses from sensory neuron to cell body)

One axon (carries nerve impulse from cell body to motoneuron)

Question 5

What are sodium potassium pump

Answer 5

They use active transport to move three sodium ions out of the neuron for every two potassium ions moved in

ATP is needed to do this

Question 6

How are cell membrane is polarised at rest part one

Answer 6

When neuron is resting the outside of the membrane is positively charged. This is because they are more positive ions outside the cell that inside.

Membrane is now polarised there is a difference in charge. The voltage across the membrane is called the resting potential it’s -70 Mac

Resting potential is created and maintained by sodium potassium pump and potassium iron channels in a neurons membrane.

Question 7

How are cell membrane is polarised at rest part two

Answer 7

Sodium potassium pump move sodium ions out but the membrane is a permeable to sodium ions so they can’t do fuse back in this creates a sodium on electrochemical gradient. Because there are more positive sodium ions outside the cell done inside.

Sodium potassium pump move potassium irons in membrane is permeable to pass on mine so they do fuse back out through potassium ion channels.

This makes the outside is a positively charged compare to inside