functional neuroanatomy Flashcards
Outline Cajal and Golgi’s thoughts on the neuron
Golgi and Cajalshared Nobel prize in Physiology or Medicine (1906) even though they had different views on brain structure! − Golgi thought that neurons were continuous,
• i.e. they physically touched each other (reticular theory) − Cajalthought that neurons are contiguous,
• i.e. small gaps between them (Neuron theory/doctrine)
• This means that
− 1) cells/neurons are independent from one another
• Structurally, metabolically, and functionally
− 2) information has to be transmitted over the tiny gaps
Outline the diffrent sites in a neuron
Input zone
i. Dendrites–where neurons collect and integrate information from other cells
2. Integration zone
i. Cell body (soma or somata) –where the decision to produce a neural signal is made
3. Conduction zone i. Axon –where information is transmitted over great distances
4. Output zone i. Axon/synaptic terminal –where the neuron transfers information to the other cells
What are the different types of neuron and their functions?
Multipolar neurons are most common in the brain
• Motor neurons –muscle control
• Interneurons –relay and integrating information for learning and memory
Bipolar –common in sensory systems, such as vision −
Unipolar –also seen in sensory systems, such as touch
What are the glial cells?
glial cell or gilia- non-neuronal cells in the CNS
1. Astrocytes
- Microglia
- Oligodendrocytes
- Schwann cells
what are astrocytes?
Astro means star in Greek
• Diffuse connections
• Each astrocyte can connect with up to 100,000 neurons
• Whilst neurons have stayed the same in evolution, astrocytes have grown more complex
- Forming and modulating neuronal connections during development
- Regulate bloodflow to active neurons
- Create scar tissue stopping spread of damage to neighbouring tissue
what are microglia?
As the name suggests they are very small
• The brain’s clean-up crew
• Travel to injured sites to remove debris • Microglial disfunction in Alzheimer’s disease
bit like WBC
what are Oligodendrocytes and Schwann Cells
Both oligodendrocytes and Schwann cells are involved in myelination − i.e. creating a layer of fat around the axon to speed up neural transmission
• Oligodendrocytes do this in the brain and spinal cord • Schwann cells do this in the rest of the body
outline GBS and MS
Multiple Sclerosis (MS) and Guillain Barre Syndrome (GBS)
• Immune system attacks the myelin produced by oligodendrocytes (MS) and Schwann cells (GBS)
• Probably an autoimmune disease
• Inflammation of CNS nerves
• Affects insulating layer of axons
What is the difference between the CNS and PNS?
Central Nervous System (CNS) • Brain and Spinal cord • Peripheral nervous system (PNS) • All nerves and neurons that reside outside, or extend beyond, the CNS • Nerve = an enclosed bundle of axons
Outline the structural subdivisions of the PNS
structural:
cranial adn spinal nerves
functional:
Functional subdivisions
• Somatic nervous system
• Autonomic nervous system
- Sympathetic nervous system
- Parasympathetic nervous system
Outline the spinal nerves
31 pairs of spinal nerves • One pair for each spinal segment: − 8 cervical nerve pairs (Green) − 12 thoracic nerve pairs (blue) − 5 lumbar nerve pairs (purple) − 5 sacral nerve pairs − 1 coccygeal nerve pair
What does each nerve contain?
Each nerve has a − Ventral (toward front) root • Contains efferentfibres • i.e. projecting away from the brain/CNS − Dorsal (toward back) root • Contains afferentfibres • i.e. projecting towards the brain/CNS
Outline the monosynaptic reflex arc
stimulus hits leg
quadracepts contract
cell body of sensory neuron in dorsal root ganglion
links o grey matter in spinal cord
impulse straight to motor neuron which triggers hamstring to coil.
Outline the SNS and ANS
Somatic nervous system
• Soma is Latin for Body − i.e. the somatic nervous system is part of the PNS that controls voluntary body movements and conducts sensory information
Autonomic nervous system
• Autonomous, i.e. little conscious awareness or control • Part of the PNS that controls homeostasis
• In charge of circulation, breathing, digestion, sexual function
• Usually not subject to voluntary control
− Sympathetic nervous system
− Parasympathetic nervous system
what is the difference betwee parasympathetic and sympathetic nervous systems?
PSNS = rest and digest SNS= fight or flight
