The Nervous System Flashcards
(32 cards)
What are the two divisions of the nervous system and their components ?
- The central nervous system- brain & spinal cord
- The peripheral nervous system- all other nerves
What are the divisions of the peripheral nervous system?
Autonomic nervous system: parasympathetic and sympathetic
Somatic nervous system: Sensory (afferent) and Motor (efferent) division
What are the cells of the nervous system?
Neurones
Neuroglial / Glial Cells
What are the two properties of neurones?
Irritability
conductivity
What are the key features of neurones?
Cell body
Axon
Schwann Cells
Nodes of Ranvier
Dendrites
Synaptic end bulb
What do Schwann cells do?
Layers form the myelin sheath
Acts an insulator
What are the nodes of Ranvier and what do they do?
Gaps in myelin sheath
Assist rapid transmission of action potentials in myelinated neurones
What is the function of a dendrite?
Form synapses with other dendrites
Provide a large surface area to receive information to pass to the cell body
Name the neuroglial cells.
Microglia - act like immune cells in CNS
Astrocytes - blood brain barrier in CNS
Oligodendrocytes - produce myelin in CNS
What is the main function of Astrocytes?
Main supporting tissue of the CNS
Forms part of the blood brain barrier.
What do sign synaptic end bulbs contain?
Synaptic vesicles containing neurotransmitters.
A nerve impulse running TO the brain and CNS is known as?
A nerve impulse running FROM the brain and CNS is known as?
Afferent (sensory)
Efferent (motor)
Give 3 characteristics of nerve impulses?
Travels in one direction
Can only send one message at one speed
The frequency or number of pulses can vary
What is the characteristic of the ion channels in the Axon?
Voltage gated
What are the stages in a neural impulse?
• Resting neuron
• Excitatory stimulus
• Sodium channels open
• Sodium irons enter the neuron
• Potassium channels open
• Potassium ions leave the neuron
• Recharging phase
How does a nerve impulse transmit to the next nerve?
• Neurotransmitters stored in vesicles in synaptic end knob
• Neurotransmitter released into synapse
• Nearby transmitter received by neighbouring dendrite
Where are neurotransmitters made?
In the cell body of the neurones
Name two neurotransmitters
Noradrenaline
Adrenaline
Dopamine
Histamine
Serotonin
Acetylcholine
Give one example of the importance of nerve impulses in dentistry
Local anaesthesia
Neuralgia
What is a nervous or neurological disorder
are physical conditions/diseases that affect the central and peripheral nervous systems
Name some disorders that affect the central nervous system
•Brain tumours
•Encephalitis
•Epilepsy
•Meningitis
•Multiple Sclerosis
•Alzheimer’s
•Parkinson’s
•Huntington’s
Name some disorders that affect the peripheral nervous system
•Peripheral neuropathy e.g. carpel tunnel
•Diabetic polyneuropathy
•Guillain-Barre syndrome
•Sciatica
•Facial nerve paralysis
What are the causes or nervous disorders
. Congenital
•Vascular
•Infection: fungal, viral, bacterial, parasitic
•Degenerative
•Trauma
•Environmental
•Risk Factors: habits, other conditions, gender, age, genetics
How might they present
Dysphagia, pain, muscle malfunction, changes in sensation, sleep problems
It can vary due to the condition
