Introduction to Nervous System Flashcards
Describe the structure of a neuron
Cell Body (also called a SOMA)
Neurites - axons/dendrites
Describe an axon
Single
Usually covered with Myelin or Schwann sheath
Describe a dendrite
Multiple
Thin, short extensions
Are there more neurons or glial cells ?
Glial cells
What is a major advantage of glial cells vs neurons ?
Glial cells can regenerate whilst neurons cannot.
Name the 2 glial cells involved in the PNS
Satellite cells
Schwann cells
Name the 4 glial cells involved in the CNS
Oligodendrocytes
Astrocytes
Microglia
Ependymal cells
Function of Satellite cells
Support the cell body (SOMA)
Function of Schwann cells
Myelin production in the PNS
Function of Oligodendrocytes
Myelin production in the CNS
Function of Astrocytes
+BBB
Function of Microglia
Scavengers
Function of Ependymal cells
CSF production
What is myelin ?
Insulation material
Rich in lipid and proteins
Function of myelin sheath
Makes conduction faster, requiring less energy
What types of neuroglia produce myelin ?
Schwann cells - PNS
Oligodendrocytes - CNS
Explain how Schwann cells surround the axon
The Schwann cells have a nucleus and cytoplasm.
They surround the axon by wrapping around them (Engulfing the axon)
The Schwann cells produce the myelin sheath.
Difference between Schwann cells and oligodendrocytes
Oligodendrocytes produce myelin for a number of axons, whereas Schwann is for one axon.
Oligodendrocytes are progenitor derived.
Schwann cells are neural crest derived.
How do neurons communicate ?
Via synapses
Communication is established by various neurotransmitters.
Where are neurotransmitters found ?
In vesicles in the synapse of an axon
What is a ganglion ?
A structure containing nerve cell bodies outside the CNS.
What is the gap between 2 neurones called ?
Synaptic cleft
What do the neurotransmitters bind to ?
The receptors on the next neurone.
What is a nucleus in nervous system ?
A structure containing nerve cell bodies inside the CNS.
What are the 2 major components on the nervous system ?
Gray matter
White matter
What is gray matter ?
Predominantly cell bodies of neurons and neuroglia and unmyelinated neurites
Where is gray matter found ?
On the surface of the cerebral hemispheres as well as the depths of the cerebrum.
In the brain where is the gray and white matter ?
Gray - outside
White - inside
In the spinal cord where is the gray and white matter ?
Gray - inside
White - outside
What is white matter ?
Axons - usually myelinated
Up/Down - blue
Projection fibres
Front/Back - green
Association fibres
Left/Right - red
Commissural fibres
What does the CNS contain ?
Enecephalon (BRAIN) and spinal cord
Covered in meninges
Suspended in Cerebrospinal fluid (CSF)
What does the PNS contain ?
Cranial and spinal nerves and their ganglia
What forms the CNS ?
Spinal cord
Brain stem - medulla, pons, midbrain
Cerebellum
Cerebrum
What is found in the brain stem ?
The nuclei of all but the first 2 of the 12 cranial nerves.
What are the 2 parts of the cerebrum ?
Telencephalon
Diencephalon
What forms the encephalon ?
Brain stem - medulla, pons, midbrain
Cerebellum
Cerebrum
What are infoldings of the cerebral hemispheres (convolutions) called ?
Gyri
How are Gyri separated ?
By Sulci
How are the 2 hemispheres separated ?
By the medial longitudinal fissure
What does each hemisphere contain ?
Cerebral cortex
Cerebral white matter
Nuclei (collection of cell bodies embedded in white matter)
Name the 6 cerebral lobes
Frontal
Parietal
Occipital
Temporal
Limbic - border/frame, borders the diencephalon
INSULA
What imaging techniques help us understand functions of different regions of the nervous system ?
PET, fMRI - (used in living people)
What is a way of determining the function of a lobe ?
Studying the relationship between lesion and outcome
Animal studies
Function of the frontal lobe
Motor
Voluntary muscle movement
Controlled and regulated
Functions of the parietal lobe
Sensations
Function of the occipital lobe
Visual associations
Function of the temporal lobe
Auditory - Hearing
Language
Function of left hemisphere
Dominant - Specialised for language and maths skills
Broca’s area and Wernickes area
Function of the right hemisphere
Visual-spatial skills
Creativity
Function of cerebrum
Each cerebral hemisphere receives sensory information from, and sends motor impulses to, the opposite side of the body.
Parts of the diencephalon
Thalamus
Hypothalamus
Function of the thalamus
Major relay station for - sensastions (apart from smell)
Function of the hypothalamus (6)
Autonomic control
Endocrine control
Eating
Sexual behaviour
Body temperature
Regulation of thirst
What is found in the midbrain ?
Nuclei of cranial nerves
Basal nuclei
Visual and Auditory reflex centres
What is found in the pons ?
Nuclei of cranial nerves
Connections between forebrain and cerebellum
Nuclei involved in regulation of respiration
Function of the medulla
Vital centres - regulating respiratory rhythm, heart rate and blood pressure
Non-vital centres - regulating coughing, sneezing, swallowing and vomiting
Cerebellum
Little brain
Structure of the cerebellum
2 hemispheres in cerebellar fossa
Convoluted with :
Internal gray matter nuclei
Surrounded by white matter
Outer cortex of gray matter
Function of the cerebellum
Processes and interprets impulses form motor cortex and sensory pathways and coordinates motor activity for smooth, well timed movements
Coordinates motor activity
Important for balance
Function of the spinal cord
A 2 way impulse conduction pathway and reflex centre
Name the 3 meninges - outer to inner
Dura
Arachnoid
Pia
Dura mater
Outermost
Arachnoid mater
Adhered closely to dura
Web like in appearance
Pia mater
Deepest layer
In direct contact with the CNS tissue
Enters every sulci
Highly vascular
What is epidural space ?
Between dura and bone
What is subdural space ?
Potential space between Dura and Arachnoid
What is subarachnoid space ?
Between Arachnoid and Pia
- contains cerebrospinal fluid
Where are the lateral ventricles found ?
In cerebral hemispheres
Where are the 3rd ventricles found ?
Between left and right diencephalon
Where are the 4th ventricles found ?
Between cerebellum and pons/medulla
Where are the central ventricles found ?
Spinal cord
What produces cerebrospinal fluid ?
The Choroid plexus
Describe the cerebrospinal fluid ?
Clear, cell-free fluid
Fills the cerebral ventricles
Passes from cerebral ventricles to the subarachnoid space
What absorbs cerebrospinal fluid ?
Absorbed by arachnoid granulations into dural venous sinuses.
Divisions of the motor nervous system ?
Somatic
Autonomic - sympathetic, parasympathetic
Divisions of the sensory nervous system ?
Somatic - sensations you are aware of
Visceral - organs
Special - vision, hearing, taste, smell
Function of the sensory division
Conveys information from receptors in peripheral tissues and organs to the CNS
Function of the motor division
Transmits signals from the CNS to the effector cells - (Skeletal and Smooth muscles, organs and glands)
What is another name for the sensory division ?
Afferent
What is another name for the motor division ?
Efferent
