NERVOUS SYSTEM/ CNS Flashcards
Define the 2 key components of the CNS and its function
- The brain and spinal cord
- control unit performing integration and analysis of info and then signals/commands generation as response
Define the 2 key components of the PNS and its function
- Cranial and spinal nerves
- relays information from internal and external environment up to CNS
Define afferent division of the PNS
Afferent = Sensory
- somatic and visceral sensory nerve fibres
- conducts impulses from receptors to CNS
Define efferent division of the PNS
Efferent = motor
- motor nerve fibres
- conducts impulses from CNS to effectors (muscles and glands)
Define the function of the autonomic nervous system
ANS = involuntary
- visceral motor (involuntary)
- conducts impulses from the CNS to cardiac muscles, smooth muscles, and glands
Define the function of the Somatic nervous system
SNS = voluntary
- somatic motor (voluntary)
- conducts impulses from the CNS to skeletal muscles
Define the sympathetic division the nervous system
Sympathetic = fight or flight
- mobilises body systems during activity
Define the parasympathetic division of the nervous system
Parasympathetic = rest and digest
- conserves energy
- promotes housekeeping functions during rest
List the process of function for the somatic nervous system
Somatic = voluntary
Sensory organs => afferent nerves => Integration of info send commands to motor neurons => efferent nerves => Control muscles
List the process for the autonomic nervous system
Autonomic = involuntary
Visceral organs => Afferent nerves => integration of information send commands through nerves => autonomic response => efferent nerves => parasympathetic ‘rest and digest’ or sympathetic ‘fight or flight’
Define neurons and neuroglia
Neurons = excitable cells able to transmit nervous message
Neuroglia = Specialised cells found only in close association with neurons, don’t participate directly in info transfer, support neurons and enhance function
Define grey and white matter
Grey = unmyelinated, axons without myelin, neutron cell bodies and dendrites White = myelinated, axons with myelin
Define the functions of the axon and axon terminals
Axon = Carries electrical message (action potential) along its length
Axon terminal = releases neurotransmitters to bind with post-synaptic cell
What are the 5 main sections of the CNS
- Spinal cord
- Brainstem
- Cerebellum
- Subcortical region
- Cerebral cortex
Describe the structure of the cerebral cortex
- Blanket of cells covering the cerebral hemispheres
- 2-5mm thick sheet of grey matter (including neuronal cell bodies)
Define the gyrus and sulcus
- Gyrus and sulcus divide each cerebral hemisphere into 4 lobes
- Sulci (or fissures) = the grooves
- Gyri = the bumps
- the folding created by sulci and gyri increases the amount of cerebral cortex that can fit in the skull
Function of the frontal lobe
Primary and voluntary motor cortex
Function of the parietal lobe
- Somatic sensory cortex
- Conscious perception of touch, pressure, pain, vibration, taste
Function of occipital lobe
- Visual cortex
- Conscious perception of vision
Function of temporal lobe
- auditory and olfactory cortex
- conscious perception of auditory and olfactory stimuli
Function of cerebellum
- Called ‘little brain’
- Rapid co-ordination for movement, automatic adjustments to maintain balance and posture
- In motor learning: when learning a new skill, dramatic increase in neural traffic to the cerebellum
Function of thalamus
Relay and processing centres for sensory information
Function of hypothalamus
Controlling emotions, autonomic functions and hormone production
Function of midbrain
- Processing of visual and auditory data
- reflexive motor responses
- Maintenance of consciousness
Function of pons
- relays sensory info to cerebellum and thalamus
- subconscious visceral and somatic motor centres
Function of medulla oblongata
- Relays sensory info to thalamus and to other portions of brain stem
- autonomic centres for regulation of visceral function
Function of brain stem
- contains ascending and descending nerve pathways
- Mediates complex ‘primitive’ behaviours, breathing, heart rate, swallowing, blood pressure
- mediates brain control of head and neck muscles
Function of corpus callosum
Connects the 2 hemispheres
Function of spinal cord
- Major column of nerve tissue
- Extends from foramina magnum to lumbar vertical column
