Cells and Resting Membrane potential M3

Question 1

What occurs in information systems? (LABEL)

Answer 1

a combination of sensory input and motor output and integration

Question 2

label the axon

Answer 2

Dendrites: collecting info –> presynaptic cell –> cell body and then the axon hillock –> This is the region where the plasma membrane generates nerve impulses; the axon conducts these impulses away from the soma or dendrites toward other neurons. or to the postsynaptic cell

Question 3

What is a synapse?

Answer 3

The action happens at the synapse, the point of communication between two neurons or between a neuron and a target cell, like a muscle or a gland. At the synapse, the firing of an action potential in one neuron—the presynaptic neuron—causes the transmission of a signal to another neuron—the postsynaptic neuron—making the postsynaptic neuron either more or less likely to fire its own action potential. a junction between two nerve cells, consisting of a minute gap across which impulses pass by diffusion of a neurotransmitter.

Question 4

What is the interneuron, and function?

Answer 4

Spines that collect information, the axon is branched, a lot of connections that influence that action –> the integration of signal is needed by branching axons
they connect spinal motor and sensory neurons. As well as transferring signals between sensory and motor neurons, interneurons can also communicate with each other, forming circuits of various complexity.

Question 5

What does the motor neuron do?

Answer 5

Dendrites collect info, to the cell body, axon runs down to motor neurons of the spinal cord (1 long axon that interacts with skeletal muscle) transmit impulses from the spinal cord to skeletal and smooth muscles

Question 6

What does each neuron look like?

Answer 6

LABEL`

Question 7

Sensory neuron?

Answer 7

cell body in the middle, dendrites, long axon

Question 8

Interneuron?

Answer 8

Multiple branches (cross wires), cell body one side and small LARGE DENDRITES

Question 9

Motor neuron?

Answer 9

LARGEST DENDRITES, long axons, central cell body

Question 10

What does connective tissue do?

Answer 10

Supplying nutrients and taking away waste production, insulation, provide support

Question 11

What are glia?

Answer 11

They are the supporting cells (the glue), they are vital for structural integrity and normal function of the nervous system

Question 12

CNS glia cells

Answer 12

Astrocytes (stars), microglia, ependymal and oligodendrocytes

Question 13

PNS glia cells

Answer 13

Satellite cells and Schwann cells

Question 14

What are astrocytes?

Answer 14

• apart of the CNS
• structural support
• regulate extracellular concentrations of ions and neurotransmitters
• formation of the blood-brain barrier

Question 15

What is the blood-brain barrier?

Answer 15

Blood vessel going into the brain, chemical inside the blood vessel
( the tight junctions don’t let anything squeeze out of the endothelial cells and presence of astrocytes)
- The purpose of the blood-brain barrier is to protect against circulating toxins or pathogens that could cause brain infections, while at the same time allowing vital nutrients to reach the brain- like lipid-soluble substances

Question 16

What are Oligodendrocytes and Schwann cells?

Answer 16

• both form myelin sheaths around axons for electrical insulation
• lipid membrane: the insulator

Question 17

What is the difference between Oligodendrocytes and Schwann cells?

Answer 17

Oligodendrocytes CNS and Schwann cells PNS

Question 18

What happens when the insulator is defective?

Answer 18

the cause problems with the electrical activity (prevents the nerves from functioning properly)

Question 19

Steps to the myelination of a peripheral nerve fibre (PNS)

Answer 19

1) Schwann cells envelop an axon
2) the Schwann cell then rotates around the axons, wrapping its plasma membrane loosely around it’s layers
3) the Schwann cells cytoplasm is forced from between the membrane. The tight membranes wrappings surrounding the axon form the myelin sheath

Question 20

What is the resting membrane potential?

Answer 20

It is NEGATIVE, 3 sodium ions are pumped out of the cell and 2 potassium ions are pumped into the cell (active transport -> involving ATP). Making net charge - negative charge inside of the cell and is maintained

Question 21

What is the difference between Oligodendrocytes and Schwann cells?

Answer 21

Oligodendrocytes CNS and Schwann cells PNS

Question 22

OUTSIDE

Answer 22

5mM K+, 150mM Na+, 12mM Cl-

Question 23

INSIDE

Answer 23

140mM K+, 15 mM Na+, 10mM Cl-, 100mM A- (large anions)

Question 24

Why is the resting membrane potential negative (ext)

Answer 24

Na+/K+ -ATpase pumps 3 Na+ ions out and 2K+ ions in, the membrane at rest has many leakage or constitutively open K+ channels, and very few leakage Na+ and Cl- channels. This process does not depend on voltage-gated ion channels - equilibrium potential in a neuron is -70mV, the build-up of negative charge in the neuron is limited by the electrical gradient vs. the chemical gradient of K+ out of the cell creating a negative charge.

Question 25

What occurs in the membrane potential cells

Answer 25

Rapid changes in membrane potential in excitable cells like neurons, myocytes and pancreatic cells.