(2) Functional Neuroanatomy Flashcards
What is the neuron doctrine?
- Are the basic unit of the nervous system
- Are distinct and separate from each other (rather than a single network)
- Have cell bodies, axons and dendrites
- Transmit information – in one direction only
What does the neuron do?
Receives and processes signals: Collects information, integrates information, conducts information and outputs information
What happens when a neuron connects to another neuron?
- Can stimulate other neurons (excitatory synapses/neurons)
- Can inhibit other neurons (inhibitory synapses/neurons)
- Can receive input from many neurons
- Can send output to many neurons
What are Glial cells?
also known as glia or neuroglia. Nonneuronal brain cells that provide structural, nutritional and other types of support to the brain
-Neurons and Glia are the…
- Building blocks of the NS and small
- Low (or no) contrast under microscope
- Special chemical techniques
- Static staining and fibre tracing
What do neurons do?
Receive, process, transmit and output information
The brain consists of a myriad of interconnected …
neural circuits performing under different functions
The function of the neural circuit depends on:
How the neurons are connected, how strong the connections (synapses) are and whether the connections (synapses) are excitatory (EPSP) or inhibitory (IPSP)
The function of the neural circuit can change through changes in…
synaptic strength
What functions do glial cells have?
- Were thought to just hold things together
- Protective function
- Metabolic function
- More to come in next years
- Divide throughout life
What are the 4 types of glia?
- Astrocytes: star shaped
- Oligodendrocytes: few extensions
- CNS (central nervous system)
- (Microglia: smaller than rest)
What are Astrocytes?
- Attach to the blood vessels and neurons
- Provide physical support
- Separate synapses
- Clean up debris
What are Oligodendrocytes?
- Support axons
- Insulate axons & speed up information transmission
- Wrap around them: myelin sheath
- In PNS: Schwann cells
What is Multiple Sclerosis?
- Demyelinating disease
- Induces numerous scars (multiple scleroses) in the brain
- Immune system attacks the myelin produced by oligodendrocytes
- Probably an autoimmune disease
- Inflammation of CNS nerves
- Affects insulating layer of axons
What is Microglia?
- Aren’t really a glia
- Precursors of blood cells
- Part of the brain’s immune system
- Related to macrophages
- Eat up debris and hostile bits
What is the CNS?
brain and the spinal cord
What is the PNS?
All the nerves and neurons that reside outside or extend beyond the CNS
What is a Nerve?
an enclosed bundle of axons
What are the Structural subdivisions of the PNS?
cranial nerves and spinal nerves
What are the Functional subdivisions of the PNS?
somatic nervous system, autonomic nervous systems, sympathetic nervous system, parasympathetic nervous system
31 Pairs of Spinal Nerves
-One pair for each spinal segment: 8 cervical nerve pairs, 12 thoracic nerve pairs, 5 lumbar nerve pairs, 5 sacral nerve pairs and 1 coccygeal nerve pair
Each nerve has a
Ventral (toward front) root
What are efferent fibres?
projecting away from the CNS
What are afferent fibres?
projecting towards the CNS
What is the Somatic nervous system?
-Part of the PNS that controls voluntary body movements and conducts sensory information
Autonomic nervous system: Was thought to be independent and part of the PNS that controls…
homeostasis, in charge of circulation, breathing, digestion, sexual function
What is the brain and skull?
- The largest part of the nervous system
- Cushioned by fluid, protected by bone
What is the Brain protected by?
skull
What is the Spinal cord protected by?
vertebrae
What are Meninges?
the three protective sheets of tissue - dura mater, pia mater and arachnoid - that surround the brain and the spinal cord
The CNS floats in the
cerebrospinal fluid (CSF) -
What is the CSF for?
- Protection
- Nutrition
- Outside the CNS
- Sub-arachnoid space
- Inside the CNS
- Four ventricles
- Central canals
What is white matter?
a shiny layer underneath the cortex that consists largely of axons with white myelin sheaths
What is grey matter?
areas of the brain that are dominated by cell bodies and are devoid of myelin
The naked eye can distinguish
grey and white parts in the brain and spinal cord
-Lateral:
to the side
-Medial:
to the middle
-Ipsi:
same
-Contra:
opposite
-Ipsilateral:
on the same side
-Contralateral:
on the opposite side
-Bilateral:
on both sides
-Superior:
to the top
-Inferior:
to the bottom
-Anterior:
to the front
-Posterior:
to the back
Dorsal:
towards the backbone
Ventral:
towards the stomach
-Rostral:
towards the snout
-Caudal:
towards the tail
What is the Brainstem classification?
(= hindbrain + mesencephalon – cerebellum)
What is the Diencephalon classification?
(= thalamus + hypothalamus)
What is the Forebrain classification?
(= isocortex + basal ganglia + limbic system)
What is the purpose of the spinal cord?
- Connects the brain to the body
- Houses local reflex pathways
- E.g. patellar reflex
What is the purpose of 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
What does the midbrain contain?
The midbrain contains important sensory and motor centres
What is the purpose of the cerebellum?
- Interfaces with the pons
- Receives sensory and motor information
- Massive fibre bundles connect it to the brainstem
- Coordinates movement
- Balance
- Motor planning
- Motor learning
- Eye movement control
Where is the The Diencephalon and what does it consist of?
- Between brain
- Consist of the thalamus and hypothalamus
What is the Thalamus?
- Complex cluster of nuclei
- Motor nuclei
- Sensory nuclei
What does the thalamus do?
- Connected to almost any area of cortex
- Most important relay station for outputs from and inputs to the cortex
- Involved in regulating sleep and wakefulness
What is The Hypothalamus and where is it located?
- Below the thalamus
- A cluster of numerous nuclei
What does the hypothalamus regulate?
- Regulates homeostasis, metabolic processes, autonomic activities
- Body temperature
- Hunger
- Thirst
- Circadian cycles
- Reproductive behaviour
- Links nervous and endocrine (hormone) systems via pituitary gland
Subcortical nuclei important for
movement
Subcortical and allocortical structures important for
learning, memory and emotion
What is the Basal Ganglia comprised of?
- Caudate nucleus
- Putamen
- Globus pallidus
- Substantia nigra (midbrain)
What does the Basal Ganglia control?
- Important for movement control
- Degenerative diseases
- Parkinson’s disease
- Huntington’s disease
What is the Limbic System involved in?
-Involved in emotion (recognition & production), motivation and emotional memory
-Hippocampus is essential for
memory formation
What is the largest area of the brain?
the cerebrum
What does the cerebrum consist of?
Consists of the two cerebral hemispheres connected by a large white matter fibre bundle – the corpus callosum
What is the outer layer of the cerebrum?
The outer layer of the cerebrum is grey matter – the cerebral cortex
-Underneath the cerebral cortex are massive nerve fibre bundles – cortical white matter
The type of cortex in the cerebrum is called
isocortex or neocortex
Isocortex has _____ of cells
-Allocortex has _____ cell layers
six layers
less than six
Each hemisphere of the cerebral cortex forms a single
deeply folded surface which allow allow larger surface area
Gyrus (pl. gyri) =
ridge
Sulcus (pl. sulci) =
groove
Fissure =
deep sulcus
The surface of the cerebral cortex is organized into cortical areas, Each area is defined by having a unique combination of 3 [or 4] specific criteria:
- Physiology (function)
- Architecture (anatomy)
- Connectivity (connections)
- [Topography (maps)]
four lobes, all serve similar functions
- Frontal lobe
- Parietal lobe
- Temporal lobe
- Occipital lobe
What does the Occipital lobe do?
- The smallest of the four lobes
- Concerned with visual processing
- Separated from parietal lobe by parieto-occipital sulcus
- Calcarine sulcus – primary visual cortex
What is the Parietal Lobe important for?
- Somatosensory perception
- Intersensory integration
- Spatial vision
- Spatial attention
- If lesioned
- Visual neglect
- Gerstmann’s syndrome (dysgraphia, dyscalculia, finger agnosia, left-right confusion)
- Bálint’s syndrome (optic ataxia, optic apraxia, simultaneous agnosia
Where is the Parietal Lobe?
-Separated from frontal lobe by central sulcus (fissure)
What is the temporal lobe important for?
High-level visual processing
- Object recognition
- Face recognition
- Medial temporal lobe
- Memory
- Amygdala
- Emotion, fear
Where is the Temporal Lobe located?
-Separated from frontal lobe by Sylvian fissure (lateral sulcus)
What is the frontal lobe important for?
- Makes us human
- Makes us grown up
- Functions
- Movement
- Impulse control, judgement, language production, memory, problem solving, sexual behaviour, social behaviour
- Involved in planning, coordinating, controlling and executing behaviour
Where is the frontal lobe located?
- Separated from
- Parietal lobe by central sulcus
- Temporal lobe by lateral sulcus
