Overview Flashcards
What are the functions of the nervous system?
- Communication
- Regulating internal events
- Organising behaviour
- Information storage (memory)
- Sensations, perceptions, emotions
- the cells responsible for these are Neurons and glia
What is more numerous - neurons or glia?
Glial cells
What are the functions of glial cells?
- Supportive, nutritive role
- Myelin formation
- Schwann cells (PNS)
- Oligodendrocytes (CNS)
What is the functions for astrocytes?
Involved in nutrient supply to neurons in CNS
What is the function of microglia?
Defence role, phagocytic
What is the function of ependymal cells?
Involved in production of cerebrospinal fluid and controls the movement of fluid
What is the function of oligodendrocytes?
Neuronal support and myelin formation in CNS
What is the function of Schwann cells?
Neuronal support and myelin formation in PNS
What are neurones and what are their functions?
- Excitable cells
- Generation and transmission of signals
- Synaptic processing: memory
- Various types with structure related to function
What is included within the PNS?
- Spinal nerves
- Cranial nerves
What is included within the CNS
- Spinal cord
- Brain
What is ‘somatic’ associated with?
Things that have conscious information
What is ‘visceral’ associated with?
Things that have unconscious information
What does afferents mean?
Going towards the CNS
What does efferents mean?
Going away from the CNS
How many pairs of spinal nerves are there?
31 pairs
What are the 31 pairs of spinal nerves?
- 8 cervical
- 12 thoracic
- 5 lumbar
- 5 sacral
- 1 coccygeal
What is a dermatome?
An area of skin that is supplied by a single spinal nerve (sensory neurons)
What is a myotome?
A group of muscles innervated by a single spinal nerve (motor neurons)
What does each spinal nerve contain?
Many sensory and motor axons
Which nerves are part of the ventral root?
Motor nerves
Which nerves are part of the dorsal root?
Sensory nerves
Is the ventral root anterior or posterior?
Anterior
Is the dorsal root anterior or posterior?
Posterior
What is a nerve plexus?
A network of nerves that seem to be tangled that mostly serve the limbs. Each network is a network of nerves that come together then redistribute themselves out with a different distribution of nerves into the limbs
How many cranial nerves are there?
12 pairs
What do afferent (sensory) nerves do?
- Carry information to CNS
What are afferent signals in somatic nerves associated with?
Sensations/perceptions
Do afferent signals from internal organs usually give rise to sensations?
No
What do efferent (motor) nerves do?
- Carry information away from the CNS
- Cause actions: muscle contractions etc
What do somatic efferents do?
Control voluntary muscle
What do visceral efferents do?
Constitute the autonomic nervous system - which controls smooth and cardiac muscle and some glands
What are the 5 types of nerve axon?
- A-beta fibre
- A-alpha fibre
- C fibre
- A-gamma fibre
- A-delta fibre
Which of the following are myelinated/unmyelinated:
- A-beta
- A-delta
- A-alpha
- A-gamma
- C fibre?
- A-beta: myelinated
- A-delta: myelinated
- A-alpha: myelinated
- A-gamma: myelinated
- C fibre: unmyelinated
Are A-alpha fibres motor or sensory?
- Some sensory neurons
- Motor neurons
Are A-beta fibres motor or sensory?
- Sensory neurons
Are A-gamma fibres motor or sensory?
- A special form of motor neuron
Are A-gamma fibres motor or sensory?
- Sensory neurons
Are C fibres motor or sensory?
- Sensory neurons
- Some autonomic nerves
