brain introduction Flashcards
what is white matter and what comprises it?
it is made from myelin from axons of neurons and consists of tracts, commissures, lemnisci, funiculi, fasciculi, capsule, column, peduncles
what is a tract?
location of a pathway
what is a commissure?
a tract that connects hemispheres
lemniscus?
a narrow strip of fibres
funiculi?
a rope or a cord
fasciculi?
bundle
capsule?
a sheet of white matter that borders a nucleus (grey matter)
what is a column?
it is longitudinally running fibres that are separated by other structures
what is a peduncle?
a stem or a stalk containing axons that connects parts of the CNS
what is grey matter and what does it comprise?
collection of cell bodies of neurons that is made of cortex, nuclei, ganglia, afferents, efferents and reticular formations
what are afferents?
they are axons taking information towards the CNS
what are efferents?
they are axons taking information away from the CNS
what is a cortex?
it is a laminated grey matter on the outside of the brain
what are nuclei?
collection of nerve cell bodies within the CNS
what are ganglia?
collections of nerve cell bodies within the PNS or CNS with capsules
what is a reticular formation?
it is a netlike arrangement where the white and the grey matter mix
what is the forebrain?
it is the cerebral hemispheres and the diencephalon - made up of the cortex, lobes, and underlying cortex white matter
what is the cortex?
it makes up most of the visible surface - up to 90% and is 10mm thick. It is folded into grooves which are names sulci and ridges which are gyri and the sulci are used to define lobes - folding increases SA
what are the lobes of the brain?
frontal - skilled voluntary movements and decision making
temporal - auditory perception and cognition and memory
occipital - visual perception
parietal - perception of the body and visuospatial location
what is the underlying white matter of the cortex for?
it allows for many connections between the cortex and CNS structures. The grey matter or diencephalon is made of the hypothalamus, thalamus and basal ganglia and is deep to the white matter. The thalamus is for directing inputs to cortical areas as a relay centre, the hypothalamus for ANS linking to endocrine system to the cerebrum and the BG for motor control, cognition and non motor behaviour made of the caudate, GP and putamen to name a few
what is the brainstem made of?
the midbrain, pons and medulla
what are the main functions of the midbrain?
special senses and sensory and motor control for the head and the neck via the cranial nerves. It is also for autonomic regulation of the body, regulates consciousness and is the pathway between the SC and the brain.
what does the midbrain surround?
the cerebral aqueduct which is made of the tectum (superior and inferior colliculi) and the cerebral peduncles
where are the pons and medulla oblongata found?
the pons is the bridge to the cerebellum and the medulla is contiunous with the spinal cord
what is the cerebellum?
it is located in the dorsal aspect of the brain stem and is separated from it by the fourth ventricle of which it forms the roof. It is attached by cerebellar peduncles (inferior, middle and superior) and has a folded cortex, white matter and deep nuclei.
what is the function of the cerebellum?
it coordinates movement and balance
what does contralateral and ipsilateral mean?
contralateral - controlling structures on other side of body
ipsilateral - controlling structures on same side of body
what are neurones?
they are the most basic functional unit of the NS, and are specialised with specific shapes. They all have processes called dendrites, axon and cell body for integration
what is the basic function of neurones?
they convey information via electrical signals and receive, integrate and transmit
where do afferent or sensory neurons travel?
away from the PNS or from receptors to the CNS
where do efferent or motor neurons travel?
carry information from the CNS to peripheral receptors
what is the function of the smaller interneurons?
they link afferents with efferents within the CNS
what is contained within the cell body of a neuron?
the nucleus with genetic information and organelles for metabolism