Neural Signalling DP IB Biology: SL

Flashcards based on Neural Signalling DP IB Biology: SL lecture notes.

What does the central nervous system (CNS) consist of?

The brain and spinal cord.

What does the peripheral nervous system (PNS) consist of?

All of the nerves in the body.

What is a nerve?

A bundle of neurones.

Where does the peripheral nervous system spread out from in the central nervous system?

The brain and spinal cord.

What is the long fiber in a neuron that transmits signals?

Axon.

What type of cell insulates the axon?

Schwann cells.

What do the Schwann cells form around the axon?

Myelin Sheath.

What are the extensions on the cell bodies and axon terminals of neurons that allow connection and communication with other neurons?

Dendrites.

What are the three main types of neurons?

Sensory, relay, and motor neurons.

What is the function of sensory neurons?

Carry impulses from receptors to the CNS.

What is the function of relay (intermediate) neurons?

Found entirely within the CNS and connect sensory and motor neurons.

What is the function of motor neurons?

Carry impulses from the CNS to effectors (muscles or glands).

What is a nerve impulse?

A momentary reversal in the electrical potential difference across the neuron cell surface membrane.

What is the typical resting potential of a neuron?

-70 millivolts (mV).

What are the carrier proteins that actively transport sodium ions out of the axon and potassium ions into the axon?

Sodium-potassium pumps.

What processes contribute to establishing and maintaining resting potential?

The active transport of sodium ions and potassium ions and a difference in rates of diffusion of sodium ions and potassium ions.

What is depolarization?

Reversal of the electrical potential difference across the membrane.

What are two key features that affect the speed of transmission in neurons?

Myelination of the neuron and diameter of the neuron.

What is saltatory conduction?

Electrical impulses effectively jump from one node of Ranvier to the next speeding up transmission.

How is the myelin sheath formed?

Schwann cells wrapping themselves around the axon, forming a myelin sheath.

What is correlation?

An association or relationship between variables.

What does a correlation coefficient (r) indicate?

Indicates the strength of the relationship between variables.

What is perfect correlation?

When all of the data points lie on a straight line with a correlation coefficient of 1 or -1.

What is the synaptic cleft?

Very small gap separating two neurones.

What triggers an influx of calcium ions into the presynaptic cell?

Depolarization.

What are neurotransmitters?

Chemical messengers released into the synaptic cleft.

What is a common neurotransmitter?

Acetylcholine (ACh).

What is the role of synapses in the direction of nerve impulses?

Ensures one-way transmission of impulses.

What is the function of acetylcholinesterase?

Hydrolyzes ACh molecules into acetate and choline to prevent permanent depolarization.