Nervous System Flashcards
Describe the anatomical terminology for the brain:
Medial (towards middle - great longitudinal fissure) or lateral (towards sides)
Superior and Inferior - as normal
Dorsal vs Ventral (brain on angle: dorsal above, ventral below; spinal cord: dorsal towards back, ventral towards front)
Rostral (towards forehead) vs Caudal (towards occipital lobe)
How is the Nervous system divided?
Central -> brain and spinal cord
Peripheral -> somatic vs autonomic (sympathetic vs parasymphetic)
Function of the Central Nervous System:
Receives and intergrates information from rest of body
Coordinates activity of the body
What are the two groups of cells making up the nervous system?
Neurons and glial cells
Describe the structure of a neuron and the various types:
Structure:
Dendrites - recieve messages from other cells
Cell body - cell’s life support centre
Axon - passes message away from cell body to other neurons, muscles or glands
Myelin sheath - covers the axon of some neurons, aids in speed of neural impulse
Nodes of Ranvier - gaps in myelin sheath which action potential jumps between
Terminal branches of axon - form junction with other cells
Various types:
- Myelinated vs non-myelinated
- Different lengths
- Bipolar (interneuron), Unipolar (sensory neuron), multipolar (motorneuron, interneuron, pyrimidal cell)
What are the 5 different types of glial cells? Where are they found?
What is their function?
Astrocytes - CNS - structural and metabolic support for neurons, resident immune cells, nourish and form BBB
Ependymal cells - CNS - produce CSF, promote CSF circulation, on surface of ventricles
Microglial cells - CNS - immune cells
Oligodendrocytes - CNS - produce myelin sheath around neurons
Schwann cells - PNS - produce myelin sheath
What is the difference between grey and white matter? Where is each found generally in the brain and spinal cord?
Grey matter: more cell bodies, dendrites and axon terminals, contains synapses, more glial cells and blood vessels
White matter: mainly comprised of axons connecting grey matter
Brain: grey on outside, white inside
Spinal cord: white on outside, grey on inside
What are the grooves and ridges of brain called?
Sulci - grooves
Gyri - ridges
What are the 3 function areas of the brain?
Cerebrum
Brainstem
Cerebellum
What makes up the cerebrum?
Cerebral cortex (divided into lobes and cortexes) and white matter
Different lobes of the brain?
Frontal, parietal, occipital and temporal
What is the brainstem divided into?
Midbrain, pons and medulla
What are the different developmental areas of the brain? What functional units comprise each area?
Cerebrum: cerebral cortex, white matter, basal nuclei
Diencephalon: thalamus and hypothalamus
Midbrain: part of brainstem
Pons: part of brainstem
Medulla oblongata: part of brainstem
Cerebellum
What are the different developmental areas of the brain? What functional units comprise each area?
Cerebrum: cerebral cortex, white matter, basal nuclei
Diencephalon: thalamus and hypothalamus
Midbrain: part of brainstem
Pons: part of brainstem
Medulla oblongata: part of brainstem
Cerebellum
What are the deep structures of the brain?
Limbic system: amygdala and hippocampus
White matter tracts
Thalamus
Hypothalamus
Basal ganglia
What are the different ventricles of the brain?
Lateral ventricle, Interventricular forament, third ventricle, aqueduct of midbrain, fourth ventricle
What is the function of the frontal lobe (6)?
Voluntary movement
Expressive language
Higher intellect
Personality
Mood
Social conduct
What is the function of the parietal lobe?
Language and calculation (dominant hemisphere), visuospatial functions (non-dominant)
What is the function of the temporal lobe?
Memory and language, including hearing
What is the function of the occipital lobe?
Vision
Lable the different cortexes on a diagram
-
Function of midbrain (5):
Vision
Hearing
Motor control
Sleep-wake cycle
Consciousness
What is the function of the pons (2)?
facial expression/ sensation
body eqm/ posture
What is the function of the medulla (6)?
Blood pressure
Breathing
Swallowing
Coughing
Vomiting
Digestion
What is the function of the cerebellum?
balance/ posture, coordination of movement
What is the function of the two components of the limbic system?
Amygdala - emotions and emotional behaviour
Hippocampus - learning and memory
What is the function of the thalamus?
Sensory relay sensor between spinal cortex and cerebral cortex
What is the function of the hippocampus?
memory
What is the function of the basal ganglia?
Movement and reward
What is the function of the hypothalamus?
Regulates body functions
What is the function of the ventricles?
Produce and contain CSF
What regions can the spinal cord be divided into?
Cervical, thoracic, lumbar and sacral
How many cervical nerves are there?
8
Which cervical nerves form the sympathetic nervous system?
T1 - 12
Which nerves form the parasympathetic nervous system?
Cranial nerves and S4
What are spinal cord tracts? How are they divided?
Bundles of nerve fibres running up and down spinal cord. They can be ascending/ descending and autonomic/ sensory/ motor.
Each tract has different functions and each tract occupies specific region of cord.
Draw and label a diagram of a cross section of a spinal cord
-
What is the function of the dorsal horn?
Contains neurons that receive somatosensory information from the body which is transmitted via ascending tracts to brain
What is function of ventral horn?
Mainly contains motor neurons exiting spinal cord to innervate skeletal muscle
What are functionof intemediate collumn and lateral horn?
Contain neurons that innervate visceral and pelvic organs
What are the 3 layers of the meninges and spaces between?
Epidural potential space: between skull and dura
Dura mater: formed from periosteal and menigeal layer
Subdural space: between dura and arachnoid, contains bridgin veins
Arachnoid mater: middle layer, no innervation and avascular
Subarachnoid mater: contains CSP, cerebral arteries and arachnoid trabeculae
Pia mater: tightly adhered to brain and spinal cord surface, highly vascularlised
Difference between meninges in spinal cord to in brain:
Epidural space in spinal cord contains fat
Main function of meninges:
Protect brain
Supporting framework of arteries, veins and venous sinuses
Enclose a fluid-filled cavity (subarachnoid space) vital for brain function as contains CSF
Composition of CSF
Clear, colourles liquid
Very few cells
Similar to blood plasma with much lower protein levels and different electrolyte levels
How is CSF produced?
Produced by choroid plexus which is made of fenestrated capillary loops covered by layers of ependymal cells
Blood plasma flows through capillary loops (active/ passive transport and osmosis) and met by barrier caused by tight junctions between ependymal cells
Movement of CSF
Lateral ventricle -> 3rd ventricle -> 4th ventricle -> subarachnoid space or central canal of spinal cord
How is CSF removed?
Drains into superior venous sinus through arachnoid villi down pressure gradient
Function of CSF
Protection: cushioning, limits neural damage
Buoyancy: reduces weight of brain
Chemical stability: environment for proper functioning due to electrolyte levels
What is the blood-brain barrier?
Several features preventing harmful substances entering brain and spinal cord forming a highly selective barrier.
Example of BBB in capillaries, ventricles and areas of higher permeability:
Capillaries: tight junctions between endothelial cells, thick continous BM, astrocyte processes cover vessels
Ventricles: tight junctions between ependymocyte cells lining ventricles and spinal canal
Higher permeability: sensory functions (postrema in medulla detects toxins and causes vomiting), secretory factors (pituitary glands)
Function of BBB
Keeps out toxins, pathogens, etc
Stops fluctuations in ion nutrient, metabolite conc in CNS
Permeable to substances that diffuse across
Active transport for specific substances
What makes up the Peripheral nervous system?
31 spinal nerves
12 cranial nerves
What is a Dermatome and myotomes?
Each spinal nerve contains many sensory and motor axons
Axons supply structures in well defined parts of body
- For sensory neurones, these regions are called dermatomes
- Motor neurones supply blocks of muscles called myotomes
What are the different types of nerve in the PNS?
- Pseudo-unipolar neuron: 1 extension from its cell body and splits into 2 branches (one goes peripherally, other centrally)
- Mutlipolar neuron: single axon and many dendrites, typically motor neurons
- Autonomic multipolar neuron: synpase between 2 neurons
Cranial nerve I: name and function
Olfactory
Smell
Cranial nerve II: name and function
Optic
Vision
Cranial nerve III: name and function
Oculomotor
Eye movements
Cranial nerve IV: name and function
Trochlear
Eye movement
Cranial nerve V: name and function
Trigeminal
Motor to muscles of mastication (chewing)
General sensory to face
Cranial nerve VI: name and function
Abducens
Eye movement
Cranial nerve VII: name and function
Facial
Muscles of facial expression
Sensory innervation of anterior 2/3 of tongue
Cranial nerve VIII: name and function
Vestibulocochlear
Hearing and balance
Cranial nerve IX: name and function
Glossopharyngeal
Swallowing and taste
Cranial nerve X: name and function
Vagus
Wandering nerve supplying heart, lung, gut, etc
Cranial nerve XI: name and function
Spinal accessory
Neck and muscle
Cranial nerve XII: name and function
Hypoglossal
Muscles of the tounge
Pneumonic to remember cranial nerves
On On On They Travelled And Found Voldemort Guarding Very Ancient Horcruxes
