The anatomy of the nervous system Flashcards
What are the two broad classes of cells that form normally functioning brain tissue?
Neurons and neuroglia (glial cells)
What properties do neurons have that differs them from other body cells?
Dendrites, axon, synapse
Explain the dendrite
Usually thicker and shorter than the axon, highly branched so allows for a dense network of processes
Explain the axon
Excitable - allows for the generation and propagation of action potentials
Explain the synapse
The point of specialised contact between two neurons
Explain the spines
The project from the surface of the dendrites. Receives most of the excitatory output. It has a neck and head, and contains the filaments actin and alpha+beta tubulins. Has fibres
What is the name of a neuron with only 1 dendrite?
Bipolar neuron
What is the name of a neuron with more than one dendrite?
Multipolar neuron
What is the length of the axon if containing golgi type 1?
long and large axon
What is the length of the axon when containing golgi type 2?
short axon
What are the three different shapes of the cell body?
Ovoid, fusiform, triangular
Where are pyramidal cells found?
In the cerebral cortex
What cell body shape do pyramidal cells have?
Triangular
What type of neuron is a pyramidal cell?
multipolar
What are the dendrites of pyramidal cell like?
Spiny
Where does the axon extend from in a pyramidal cell and what type of golgi does it have?
The base, type 1
Where are spiny stellate cells found?
Cortex
What cell body shape does the spiny stellate cell have?
ovoid cell body
What type of neurons are the spiny stellate cells?
multipolar but the dendrites are horizontal/radial from the cell body
What type of dendrites does the spiny stellate cells have?
Spiny
What type of neurons are spiny stellate cells? (not multi/bipolar) and what type of golgi do they contain?
interneurons, golgi type 2
What cell body shape do dopaminergic cells have?
fusiform
What type of neuron is a dopaminergic cell?
multipolar
Where does the axon emerge from in a dopaminergic cell?
from the cell body or from one of the dendrites
What type of golgi do dopaminergic neurons have?
golgi type 1 as it is a projection neuron
What does the degeneration of dopaminergic neurons lead to?
Parkinson’s disease
Where are purkinje cells found?
Cerebellum
What cell body shape do purkinje cells have?
Ovoid
What type of neuron is a purkinje cell?
Bipolar
Describe the dendrites of a purkinje cell?
Highly branched dendritic tree and spiny
What type of golgi does a purkinje cell have?
Golgi type 1 as is a projection neuron
What does the degeneration of purkinje cells lead to?
Tremor, problems with walking, fine hand movements and speech
Why is neuroglia referred to as nerve glue?
as it holds together neurons in the CNS
What are the different forms of glia?
Oligodendrocytes, astrocytes, and microglia
What is a cell in the PNS?
Schwann cell
What do oligodendrocytes do?
Form myelin
Describe the properties of an oligodendrocyte
Single sheet of oligodendrocyte plasma membrane wrapped tightly around an axonal segment
What does the myelin do?
Insulates which speeds up the conduction of action potentials
What is the shape of astrocytes?
Star shaped
How much of the volume of the brain do astrocytes constitute?
20-50%
What do astrocytes do?
They fence in neurons - make cuffs around nodes of ranvier, ensheath synapses and dendrites and project processes to cell somas.
What are the three functions of glia?
1) induce tight junctions in endothelial cells
2) uptake of neurotransmitters
3) neurovascular coupling
What is the function of microglia?
They are representatives of the immune system in the brain
Give a process that microglia are involved in
Phagocytosis
What is the dorsal/ventral anatomical direction?
Towards the back/belly
What is the anterior/posterior anatomical direction?
Towards the front/back
What is the rostral/caudal anatomical direction?
Towards the beak/tail
What is the medial/lateral anatomical direction?
Towards the middle/side
What are the basic subdivisions of the brain?
Spinal cord, Hindbrain, midbrain, forebrain
What are the further divisions in the hindbrain?
Metencephalon, myelencephalon
What are the further divisions found in the midbrain?
Mesencephalon
What are the further divisions found in the forebrain?
Telencephalon, diencephalon
Give the name of the brain structure in the myelencephalon
Medulla oblongata
What does the myelencephalon contain?
Nuclei which controls respiration, tongue musculature, blood pressure and heart rate
Give the name of the brain structures in the metencephalon
Pons and cerebellum
What does the pons contain?
Nuclei which are involved in sleep and arousal
What does the cerebellum do/contain?
Integrates sensory information to modify motor output
What happens if the cerebellum is damaged?
Movement is jerky and poorly coordinated
What are the brain structures in the mesencephalon?
Tectum and Tegmentum
What does the tectum contain?
Inferior colliculi (auditory) and superior colliculi (vision)
Name the three major structures of the tegmentum?
Red nucleus (motor), subtantia nigra (motor), periaqueductial grey (species typical behaviours such as mating)
What the brain structures found in the diencephalon?
Thalamus and hypothalamus
Describe the thalamus
Divided into nuclei, some neurons involved in receiving input from primary senses, other neurons have unknown function
Describe the hypothalamus and it;s functions
Organises the autonomic and glandular aspects of responses related to survival, and homeostasis. Contains many nuclei (SCN - circadian rhythm)
What are the brain structures in the telencephalon?
Most of the 2 cerebral hemispheres
What does the telencephalon do>
Mediate the most complex functions
What does the primary visual cortex receive?
Sensory information
What does damage to the primary visual cortex lead to?
Blindness
What does damage to the visual association cortex do?
More complex deficits and visual agnosia - the failure to know. Able to perceive but can’t say.
What is the prefrontal cortex involved in?
Planning and emotional behaviour and personality
What does the basal ganglia consist of?
Caudate nucleus, putamen, and globus pallidus
