Anatomy of the Nervous System Flashcards
What is the CNS?
Brain and spinal cord
What is the PNS?
Nervous system outside brain and spinal cord
What are the parts of the PNS?
Somatic nervous system
Autonomic nervous system
What do afferent nerves do?
Carry sensory signals towards the CNS
What do efferent nerves do?
Carry motor signals from CNS
Sympathetic nerves
Motor nerves which project from CNS in the lumbar and thoracic spine
Parasympathetic nerves
Motor nerves which project from the brain and sacral spine
All sympathetic and parasympathetic nerves are …..
Two-stage neural paths
Sympathetic neurons synapse on second-stage neurons…
At a substantial distance from their target organs
Parasympathetic neurons synapse on second-stage neurons…
Near their target organ
these are very short
What is the longest cranial nerve?
Vagus nerve
How many pairs of cranial nerves are there?
12
Meninges in order outer to inner
Dura mater
Arachnoid mater
Pia mater
What does cerebrospinal fluid do?
Supports and cushions brain
Where is cerebrospinal fluid produced?
Choroid plexus
What is hydrocephalus?
Buildup of fluid in ventricles leading to the expansion of the walls of the ventricles and the brain
What does the blood-brain barrier do?
Prevents the passage of many toxic substances from the blood into the brain
What molecule is actively transported though the cerebral blood vessel walls?
Glucose
Neurons
Reception, conduction and transmission of electrochemical signals
Classes of neurons
Multipolar neuron Unipolar neuron Bipolar neuron Interneuron Nuclei in the CNS Ganglia Tracts Nerves
What is a ganglia?
Cluster of cell bodies in the PNS
What is a tract?
Bundle of axons in the CNS
What is a nuclei in the CNS?
Cluster of cell bodies
What is a nerve?
Bundle of axons in the PNS
Glial cells
Outnumber neurons 10 - 1 Oligodendrocytes Schwann cells Microglia Astrocytes
What is an oligodendrocyte?
Causes myelination in the CNS
What is a Schwann cell?
Causes myelination in the PNS
What is a microglia?
Respond to injury or disease by multiplying, engulfing cellular debris and triggering inflammatory responses
What is an astrocyte?
Largest glial cell
Send and receive signals from neurons to other glial cells
Control the establishment and maintenance of synapses
Modulate neural activity
Participate in glial circuits
Golgi staining
Potassium dichromate and silver nitrate
Silver dichromate made, stains some of the neurons completely black
Gives excellent view of neurons that take up the stain
Nissl staining
Cresyl violet
Penetrates all cells on slide
Binds effectively to structures in neuronal cell bodies
Can estimate the number of cell bodies an area
Electron microscopy
Provides information about the details of neuronal structure
Thin slices of neuronal tissue are coated with an electron-absorbing substance that is taken up to different degrees by different parts of the neuron
A beam of electrons is passed through the tissue onto a photographic film
Neuroanatomical tracing techniques - anterograde
Used when investigator wants to trace the paths of axons projecting away from cell bodies
Injects a chemical into an area taken up by cell bodies
Transported forward along the axons to terminal buttons
Brain removed and sliced after a few days and treated to reveal the location of the chemical
Neuroanatomical tracing techniques - retrograde
Used to trace paths of axons projecting into a particular area
Injects a chemical into and area that is taken up by the terminal buttons and transported back along the axons
Brain removed and sliced after a few days and treated to reveal the location of the chemical
Spinal cord areas
H shaped core of grey matter
Surrounded by white matter
What is grey matter composed of?
Cell bodies and unmyelinated interneurons
What is white matter composed of?
Mainly myelinated axons
All dorsal root axons are
Sensory (afferent) unipolar neurons
The neurons of the ventral root are
Motor (efferent) multipolar neurons
Telencephalon
Left and right cerebral hemispheres
Initiates voluntary movement
Interprets sensory movement
Mediates complex cognitive processes such as learning, speaking and problem solving
What is a gyri?
Ridges that stick out on the brain
What is a sulci?
Small furrows in the brain cerebral cortex
Diencephalon
Thalamus and hypothalamus
Thalamus
Lateral geniculate nuclei
Medial geniculate nuclei
Ventral posterior nuclei
Lateral geniculate nuclei
Relay station in the visual system
Medial geniculate nuclei
Relay station in the auditory system
Ventral posterior nuclei
Relay station in the somatosensory system
Hypothalamus
Plays important role in regulation of several motivated behaviours
Regulates release of hormones from the pituitary
Mesencephalon
Tectum and tegmentum
Metencephalon
Pons and the cerebellum
Important for sensorimotor function and precise movement
Myelencephalon
Medulla
Tracts carrying signals between the rest of the brain and the body
Cerebral cortex
Frontal Parietal Temporal Occipital LOBES
Frontal lobe
Precentral gyrus and adjacent frontal cortex - motor functions
Frontal cortex anterior to motor cortex - complex cognitive functions
Parietal lobe
Postcentral gyrus - analyses sensations from the body
Remaining areas in posterior parts - perceive location of both objects and our own bodies
Temporal lobe
Superior temporal gyrus - hearing and language
Inferior temporal cortex - complex visual patterns
Medial portion - certain kinds of memory
Occipital lobe
Processing of visual information
Limbic system is involved in
Four Fs Fleeing Fighting Feeding Sexual behaviour
Structures of the limbic system
Amygdala Hippocampus Cingulate cortex Fornix Septum
Basal ganglia structures
Amygdala
Caudate
Putamen
Globus pallidus
