AC 2.1 Explain Typical Features Of Neruones Flashcards
(20 cards)
What is knee-jerk response?
- Stimulus: hammer hits tendon, causing stretch receptors to lengthen
- Response: muscle contracts, causing foot to jerk upward (muscle in front of thigh stretches, stimulating stretch receptors)
- stretch receptors stimulated, send message to muscles of thigh
- muscles in front of thigh contract
- muscles in back of thigh relax
- foot jerks
Explain reflex arc in form of muscle dropping into someone’s hand
- Stimulus: Weight dropping into hand, stretching the muscle
- Response: muscle contracts, jerking arm upward
What do dendrites do
Receive the AP
What does the cell body do?
Produce neurotransmitter
What is the axon?
The conducting fibre
What are Schwann cells?
Produce myelin
What are axon terminals?
Transmit the AP
What is the myelin sheath?
Insulating fatty layer that speeds transmission in form of saltatory conduction and insulates against ions
What are the nodes of ranvier for?
They allow the AP to jump across the nodes in a process called saltatory conduction which speeds up transmission along the axon
What does the axon hillock do?
Contains many Na+ channels
What is the initial segment?
Trigger zone
Why is the axon long?
To get to far away places in the body (long distances)
Purpose of multiple dendrites?
Impulses can come from multiple sources and is useful in summation by using multiple small stimuli to produce an AP
Explain the concept of dermatomes
- An area of skin mainly supplied by a single spinal nerve
- Each of these nerves relays sensation (pain) from a region of skin to the brain
- Example is the sciatic nerve (pain from sciatica radiates from buttock down leg to the feet
Explain typical sensory neurones
- Sensory/afferent neurons convert a specific type of stimulus, via their receptors, into action potentials or graded potentials (sensory transduction)
- The cell bodies of the sensory neurons are located in the dorsal ganglia of the spinal cord.
Explain typical motor neurones
Motor/efferent neurones
- cell body is located in spinal cord, whose axon (fiber) projects to control effector organs, mainly muscles and glands.
Explain interneurones
Interneurons create neural circuits, enabling communication between sensory or motor neurons and the central nervous system (CNS).
Explain relationship of neurones to nerves
- Nerves are found in the peripheral nervous system, while neurons are found in the brain, spinal cord and the peripheral nerves.
- neuron can also be called a neurone or a nerve cell.
- Neurons conduct nerve impulses, while nerves transmit information to various parts of the body.
What is white matter
Made of axons with their myelin sheaths
What is grey matter
Made of cell bodies and their dendrites
