Nervous System Flashcards
Describe lateral, dorsal, medial, ventral, anterior and posterior
Lateral - towards side Dorsal - towards back Medial - towards midline Ventral - towards stomach Anterior - towards the front end Posterior - towards the rear end
Because humans walk upright anatomical directions are rotated by 90 degrees. So “dorsal” in the spinal cord means what? And “dorsal” in the brain means what?
Dorsal in the spinal cord means towards the back
Dorsal in the brain refers to the top of the brain
What is the midsagittal section?
Section cut down the CENTRE of the brain
What is the cross section of the brain?
Section cut at a right angle to a long structure
What 2 systems are part of the nervous system?
The central nervous system and the peripheral nervous system
What 2 parts of the peripheral nervous system are there?
Autonomic nervous system
Somatic nervous system
Where does the central nervous system work?
Brain and spinal cord
Where does the peripheral nervous system work?
Nerves outside brain and spinal cord
What 2 systems does the autonomic nervous system include?
Sympathetic nervous system
Parasympathetic nervous system
List 3 things the autonomic nervous system does
- regulated the body’s internal environment
- controls involuntary muscles (heart, intestine)
- it is unconscious and automatic
What does afferent mean? Use an example
Away from
Internal sensory signals are sent away to CNS
What does efferent mean? Use an example
To
Motor signals from CNS to internal organs
List 3 things the somatic nervous system does
- interacts with external environment
- controls voluntary muscles and sensory information to CNS
- conscious and voluntary
List 2 things the sympathetic nervous system does
- prepares the organs for vigorous activity “fight and flight”
- increases breathing and heart rate, decreases digestive activity
List 2 things the parasympathetic nervous system does
- promotes energy conserving, non- emergency functions
- generally does the opposite of sympathetic activities
What are the 2 sections of the structure of the spinal cord
Sensory nerve - enters
Motor nerve - exits
Simple reflexive behaviours take place in the spinal cord, explain this
The behaviours are called reflex, the steps required for the behaviour are called the reflex arc
List the 3 parts that make up the spinal cord and what’s inside them
Gray matter - cell bodies of motor neuroma and other cell bodies
White matter - myelinated axons
Central canal - space filled with cerebrospinal fluid
What happens when the the spinal cord is cut?
The brain loses sensation from that segment and all segments below
What’s the definition of the reflex arc?
Circuit from sensory to muscle response
List 2 positives of te reflex arc?
Evolutionary - high value for survival as they enable the organism to respond quickly
Medical - provides information on the integrity of the central and peripheral nervous systems
Describe how the reflex arc works
Sensory stimuli on “pinch of skin” - info travels via the sensory nerve into spinal cord and connects to the intrinsic neuron - intrinsic neuron connects to the motor neuron and signals “contract muscle” - the motor neuron conveys info to the muscle and the muscle contracts
What are the 3 major divisions of the brain?
Cerebral hemispheres (forebrain) - telencephalon - diencephalon Brainstem (midbrain) - mesencephalon Spinal cord (hindbrain) - metencephalon - myelincephalon
What are the 4 parts of the hindbrain? Explain them
Medulla
- tracts carrying signals between rest of the brain and body
- controls some vital reflexes
Reticular formation
- plays important role in arousal, sleep, attention
Pons (bridge)
- axons from each side of them hemisphere cross
Cerebellum
- important sensorimotor structure
- seems also involved in cognitive functions (attentional shifts)
What are the 2 parts of the midbrain and explain them
Tectum (dorsal)
- superior colliculi : visual function
- inferior colliculi : auditory function
Tegmentum (ventral)
- sensorimotor function, part of the system that deteriorates in Parkinson’s disease
What are the 2 parts of the forebrain (diencephalon) and explain them
Thalamus
- sensory relay except for olfactory information
Hypothalamus
- important for regulation of motivated behaviours
- regulates release of hormones from pituitary gland
What does the forebrain (telencephalon) do? List the 3 main part
Initiated voluntary movements, interprets sensory input and mediates complex cognitive processes
Cerebral cortex
Basal ganglia
Limbic system
Explain the basal ganglia?
Several structures that play a major role for voluntary motor responses
Stimulation of the basal ganglia results in what?
Reduction of tremor
What does the limbic system do? Explain 3 main parts
Regulation of motivated behaviours and emotions
Amygdala
Hippocampus
Cingulate cortex
Describe the layout of the cerebral cortex (telencephalon) and what it does
Large furrows - fissures
Small furrows - sulci
Ridges between furrows - gyri
Neurons communicate across hemispheres mainly through the corpus callosum
List the 4 lobes found in the hemispheres of the telencephalon
Frontal lobe, parietal lobe, temporal lobe and occipital lobe
What’s the occipital lobe?
Example: cortical blindness
Found at the very back of the brain
Receives main input from thalamic nuclei that receive visual input from the eyes
What’s the parietal lobe?
The post central gyrus is the primary somatosensory cortex
Receives main input from touch sensations and muscle receptors
What’s the temporal lobe?
Primary target for auditory information
The medial part: memory
The inferior part: complex aspects of vision
What’s the frontal lobe?
Precentral gyrus = primary motor cortex
Similarly to the homunculus the primary motor cortex is a map of the body however this time the map does not represent sensory input but motor output
What are the 5 processes in the development of Neurons?
Production of Neurons and glia from stem cells
Neurons move towards their eventual destinations in the brain
Growth of axon and then dendrites
Myelination, continues for decades
Formation of synapses, continues throughout life (synaptogenesis)
What are the two exception to “Neurons are not formed after birth”?
Olfactory Neurons
Hippocampus Neurons
What percent of Neurons are produced than needed?
50%
What is neural darwanism?
Cell death and activity of the incoming axon results in rearrangement of synapses
Result: axons become more focused
Describe the concept of “use it or lose it”
Neurons and synapses that aren’t activated by experience do not usually survive
Where does regrow the of axons occur?
Peripheral nervous system
What are 2 effects of increased sensitivity?
Compensation and chronic pain
What’s the result of reorganisation of sensory representations?
Can lead to phantom limbs
List 2 learned adjustments in behaviour
Identification and training of spared abilities
MOODLE:
Together, the somatic nervous system and the autonomic nervous system make up the ______ nervous system
Peripheral
