functional neuroanatomy Flashcards
(31 cards)
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
what is the physical structue of the human brain?
reflects the neurons cell bodies
White matter reflects the neuron axons
The brain floats in cerebrospinal fluid (CSF)
• Protection
• Nutrition
what is the difference between a sulcus a gyrus and a fissure?
Gyrus (plural gyri)
• ridge
- Sulcus (plural sulci) • groove
- Fissure • deep groove
What are the 3 ways to slice a brain
coronal- width
sagittal- length (right brain and left brain split)
Horizontal
What are the brain and spinal orientations?
Superior (Top) vs Inferior (Bottom)
• Anterior (Front) vs Posterior (Back)
• Medial (Middle) vs Lateral (Left or Right sides
Dorsal (towards back) vs Ventral (towards stomach)
• Rostral (towards nose) vs Caudal (towards tail)
• Different head/spine orientation changes this in bipedal vs quadrupedal
What is it called when brain and space orientations are on the same or different side
Ipsilateral − Same side
− Leftbody/space to leftbrain hemisphere and vice versa
• Contralateral − Switch sides − Leftbody/space to right brain hemisphere and vice versa
Outline the brainstem
Controls vital body functions
− Breathing
− Heartbeat
− Artery dilation
− Salivation
− Vomiting
• Contains the nuclei for cranial nerves III–XII
• The pons is closely connected to the cerebellum
• Important for movement and balance
• The midbrain contains important sensory and motor centres
what does the cerebellum do?
Cerebellum (latinfor ‘Little brain’)
• Own 3-layer cortex with ten ‘lobules’ (gyri)
• Own subcorticalstructures (deep cerebellarnuclei)
• 10% brain volume however, it contains ~50% of the brains 100 billion neurons
Massive computational potential
Receives sensory information directly from brainstem and additional information from isocortex
• Coordinates movement
• Balance
• Motor planning
• Motor learning
• Eye movement control
• Coordinate non-motor function
• Rule learning
• language
what are the 4 main structures of the basal ganglia?
Four main structures − Caudate Nucleus (blue) • Cognitive control
− Putamen (green)
• Motor control
− Nucleus Accumbens(red)
• Reward processing
− Globus Pallidus
• Receives outputs from all three other basal ganglia structures
• Damage leads to basal ganglia leads to: − Parkinson’s Disease − Huntingdon’s Disease
What does the thalamus do?
Complex cluster of nuclei
− Motor nuclei
− Sensory nuclei
• Connected to almost any area of cortex
− The basal ganglia and cerebellum send signals to the isocortexvia the thalamus
- Most important relay station for outputs from and inputs to the cortex
- Involved in regulating sleep and wakefulness
