Module 1.2

Question 1

Electrical gradient/polarization

Answer 1

A difference in electrical charge between the inside and outside of the cell. Resting potential.

Question 2

Selective permeability

Answer 2

Some chemicals pass through the cell membrane more freely than others do. Oxygen, carbon dioxide, urea, and water cross freely. Sodium, potassium, calcium, and chloride don’t pass at rest

Question 3

Sodium-potassium pump

Answer 3

A protein complex repeatedly transports 3 sodium irons out of the cell and 2 potassium ions in. It is an active pump that requires energy.

Question 4

Concentration gradient

Answer 4

There are more sodium ions outside of the cell so based on its concentration, it is pulled into the cell. Vice versa for potassium

Question 5

Action potentials

Answer 5

Messages sent by axons. Any stimulation that applies a depolarization stimulation to the negatively changed neuron, to make it positively charged, produced a response. The action potential response opens sodium’s channels and let’s sodium flow into the cell.

Question 6

All or none law

Answer 6

No matter the strength of the depolarization, the action potentials for the same neuron are the same intensity and velocity. Also the action potential can change from neuron to neuron, as thicker neurons have greater velocity.

Question 7

Steps of an action potentiometer

Answer 7

1. At rest there is more sodium outside and more potassium inside
2. The membrane is depolarizer
3. Sodium and potassium channels open. Initially the potassium doesn’t do much but sodium floods into the cell
4. At the peak, sodium channels close and then potassium floods out causing hyperpolarizatipn
5. The membrane returns to the original distribution but it takes time

Question 8

Charles Scott Sherrington

Answer 8

Demonstrated communication between neurons in specialized gaps called synapses. Studied reflexes on dogs.

Question 9

Reflex Arc

Answer 9

The circuit from sensory neuron to muscle response