Neural Structure & Function Flashcards
Anatomical Directions:
- Anterior & Rostral
- Posterior & Caudal
- Dorsal
- Ventral
- Medial
- Lateral
- Front
- Back
- Top
- Bottom
- Middle
- Side
A wrinkled brain has…
…a greater surface area
Function of Frontal Lobe
behavioural traits (personality, decision-making and motor control) makes sense of info about the enviro, memories and emotions and it uses this info to make decisions.
Function of Temporal Lobe
houses memories, emotions and language comprehension
contains hippocampus, V1 and Wernicke’s area
Function of Parietal Lobe
integrates info from our senses to focus attention on enviro
receives signals from OL that reflect the location of objects in our VF
Function of Occipital Lobe
decodes visual signals
Inferior Frontal Gyrus
responsible for response inhibition
home of Broca’s area (controls language production)
Function of Basal Ganglia
involved in flexibility (motor and cognitive)
control voluntary movements, habitual behaviours and emotions
Functions:
- Globus Pallidus
- Putamen
- Caudate Nucleus
- Thalamus
- Sub-thalamic Nucleus
- Substantia Nigra
- receives signals from caudate nucleus and putamen and sends info about motor control to cerebral cortex via thalamus
- works with caudate nucleus to transfer info from frontal cortex to the globus pallidus, involved in initiation and learning of motor movements
- conduit for info from cerebral cortex into basal ganglia
- relays info from senses to cortex
- dampens signals from the basal ganglia
- initiates movements by sending signals to dorsal striatum (contains neurons that produce dopamine)
Function of Limbic System
involved in emotion and motivation, learning and memory
contains cingulate cortex, thalamus, amygdala and septum
Function of Ventricular System
allows toxic substances and waste products to be removed from the brain preventing harm to the CNS
Function of Hypothalamus
responsible for functioning of organisms and communication with endocrine system
Function of Hippocampus
important for learning and memory
Functions:
- Cingulate Cortex
- Thalamus
- Septum
- Amygdala
- group of interconnected brain structures involved in emotions
- relays info from senses to cortex
- ?
- works with HC to create episode LTM
Two main types of cells:
- glial cells
2. nerve cells
Glial cells are…
Active role in…
and determining…
Two types of glial cells are…
support cells
regulating neurotransmission
structural integrity of the brain
resting glial cells and active glial cells
Astrocytes are…
Structure?
Function?
cells that control brain homeostasis
dendrite-like structure
does not conduct electricity and mainly controls the extracellular space, regulating the neurotransmitter levels
Microglia are…
immune cells that corneal the health of the brain
Oligodendrocytes are…
Function of Myelin Sheath:
Multiple Sclerosis:
Multiple/different oligodendrocytes contribute to the myelination…
cells that are involved in the formation of the myelin sheath around neuronal axons
insulation that speeds up the AP moving from the cell body to the terminal region where NT are released
demyelination of cells
of one/same neuron
Satellite cells are…
peripheral astrocytes
Schwann cells are…
peripheral oligodendrocytes
The role of radial cells (early development stages) are to….
Neuronal Precursor Cells (cells that develop inter-neurons) attach and wrap themselves….
Patients with schizophrenia have cells…
determine the placement of neuronal cells in the CNS
around stalks and move along them to the position where they need to be, once they reach the position they detach
in a different position in the HC
Nerve cells are... 1. Allows... 2, Can be subdivided in different types of cells based on... 3. They are be very... 4. They can not... 5. They are excitable and can... 6. They can communicate via... 7. They consume large amounts of energy and...
neurons
- communication from one part of the brain to the other
- size, biochemical composition and structural characteristics
- large
- divide anymore, however in parts of the brain embryonic stem cells can develop into neurons
- conduct electricity
- two different kinds of mechanisms
- without oxygen, die within a few minutes
In the hippocampus area there are specific ESC that can….
It is important for the function….
In major depression neurogenesis is reduced and antidepressants can…
fully develop into neurons and move out of the layers into other parts of the brain, allowing neurons to get into the right position
at the HC
increase this neurogenesis, the development of new neurons from ESC.
Neurons: Basic Structure
Input Part –info from other…
Propagating Part – AP…
Transferring Part – chemical messengers/NT…
neuronal cells come in
movement (electricity)
are being released
Neurons: Basic Function Cells have a.... The membrane is a... To ensure... Ions are... All cells in the body have channels for... Neuronal cells have channels for... The phospholipid bilayer is the core of the...
thick membrane surrounding them
lipophilic part (fat-loving structure)
all the components are retained within the cell
water soluble, do not like to be in a fatty environment, therefore do not move across the membrane
K+ to move through (small gaps in the fatty layer)
Na+ ions, to move electricity (AP generation)
neuronal membrane and forms a barrier to water-soluble ions
Neurons: Resting Potential
There are more K+
K+ is hydrophilic, therefore…
Under resting conditions…
inside the cell than outside the cell
unable to move across the membrane
K+ channels are open and Na+ channels are closed
Neurons: Resting Potential
1. K+ flows…
2. K+ flow is impeded by the…
3. An equilibrium is…
4. The Nernst Equation
5. In general cells are charged around…
The more K+ flows out, the more the outside becomes…
out because of the concentration gradient
electric gradient
established between the two forces
-60mV to -80mV (inside negative)
positivity charged, the more there will be an electrical gradient forcing K+ inside
Neurons: Action Potential
- When cells become stimulated above a certain threshold…
- The concentration and electric gradient…
- The polarity of the cell changes…
- At a specific polarity…
- K+ flows out again…
Na and K pushed against concentration gradients which..
Energy required to maintain…
- the Na+ channels open (voltage-gated channels - neuronal cells)
- forces Na+ into the cell
- inside positive
- Na+ channels close again
- to restore the resting potential
costs at lot of energy
the right concentration of Na (extracellularly) and K (intracellularly)
Neurons: Action Potential
Refractory Na+ channels open at ? and close at ?
When the Na+ channels close after being opened they enter…
In this state they…
which prevents the Na+ from…
Although this refractory state only lasts….
It is enough to prevent the cells from….
Moreover, it ensures that…
-70mV and 10mV into a refractory state cannot be opened opening immediately a few milliseconds firing too much action potentials move into one direction only
Neurons: Neurotransmission
Na+ channels open, AP electrical gradient moves from…
The small space between two neurons is called…
NT are synthesized in neuronal cells and located in…
Another channel opens when an AP arrives…
Ca+ flows into the cell and activates….
As a consequence of all these biochemical processes, the vesicles move…
The content of the vesicles (MT) are…
Some NT bind to a receptor, the post-synaptic cells gets a signal (activation), that signal is transmitted to another cell.
Activation of this cell leads to….
Activation of this cell may inhibit….
Activation of the post-synaptic cell or inhibition of the post-synaptic cell…
This process is very fast.
the cell body to the terminal region
the synapse
specific neurons, stored in specific vesicles
Ca+ channel
the proteins in the cells
towards the membrane and merge with the membrane and open up
released into the synaptic cleft.
the activation of the other cell.
the firing of the other cell.
info from one cell has been transferred to the other cell.
Neurons: Neurotransmission
- Biogene amines
- Amino acids
- Neuropeptides
Stored in…
Neuropeptides are…
Acetylcholine Dopamine Noradrenaline Adrenaline Histamine Serotonin
GABA
Glutamate
Aspartate
Glycine
Endorfin Enkephaline(s) Dynorphin Cholecystokinin Bradykinin Substance P Substance K Neurotensin Somatostatin Neuropeptide Y
Vesicles
Larger
Neurons: Neurotransmission
NT are synthesized in….
NT are stored in…
Peptides are not synthesized in…
There are no re-uptake transporters for….
When peptides bind to receptors, they are…
Neuropeptides work slower and….
Same cells releases more than…
Different NT are stored in…
This allows for additional…
terminal region
vesicles, released, taken up, recycled.
the terminal region, but are synthesized in the cell body.
peptides
degraded extracellularly or diffused out.
replenish themselves
one NT (generally neuropeptide and classical NT)
different vesicles
flexibility in communication between neuronal cells
Neurons: Neurotransmission
NT interact with…
There are always more than 1 receptor per NT…
The NT receptors can belong to different functional classes…
Irrespective of whether NT bind to ionotropic or metabotropic receptors, they change the…
specific receptors
not always (oxytocin has one receptor)
Ionotropic and Metabotropic
electrical properties (membrane potential) of the postsynaptic cells either depolarising it (-80mV to -70mV) or hyper-polarising it (-80mV to -90mV) leading to excitation or inhibition
Neurons: Ionotropic receptors
3 Examples:
The opening and closing of the receptor is dependent on whether a….
GABAA receptor
NMDA receptor
Nicotinergic receptor
NT binds or not (referred to ligand gated ion channels)
Neurons: Ionotropic receptors - GABAa
Activation of benzodiazepine site by itself does not affect channel opening. This will only occur after GABA has bound to the receptor: when GABA binds to the receptor, additional binding of benzodiazepines lead to an increase in the frequency with which the channel is opened
Neurons: Metabotropic receptors
Metabotropic receptors in the CNS belong to…
They all have the same overall general structure:
A single long chain of amino acids with…
This leads to a 3D structure with…
This receptor binds to a G-protein and can…
The second messenger system (G-protein) binds to the…
Gs – ? coupled to adenylate cyclase
Gi – ? coupled to adenylate cyclase
Go – coupled to…
Gq – coupled to…
G-protein coupled receptors 7 hydrophobic (lipophilic stretches) 3 extracellular and 3 intracellular loops induce many complex changes in the cell third intracellular loop
positively
negatively
ion channels
phospholipase C
Neurons: Metabotropic receptors
Amino acids sit in the…
Substances cannot flow through – do not form a channel
NT bind on the outside, it forces transmembrane domains to open that leads…
The structure of this receptor changes from…
It is detected intracellularly and leads to…
By binding on the outside, the 3D structure changes, the conformation of the receptor, which leads to activation of the intracellular routes, leading to activation of processes in the cell.
membrane
intracellularly to a closing of those intracellular parts of those transmembrane domain
the NT binding
activation of processes
Neurons: Metabotropic receptors
G-proteins binds…
In resting state (when the receptor is not activated), GDP is bound to the protein which consists of…
When the receptor is activated, the NT released from the pre-synaptic terminal binds to the…
When the NT binds, GDP is changed to…
G protein splits up…
Indirectly activates ion channels and changes inside the cell
GDP
alpha, beta and gamma tightly bound together.
outside of the receptor, compressing the outside open and the inside tightly together, the 3D structure (third intracellular domain) starts to change it’s configuration, and activates the G-protein.
GTP (additional phosphate is added), activates G-protein.
alpha unit separates from beta and gamma unit
Ionotropic Receptors Consists of multiple (5) proteins that form... Activation by a NT or drug (ligand)... Limited... Fast... Usually has multiple...
Metabotropic Receptors Consists of a... Activation by a NT or drug (ligand) splits the... More widespread... Somewhat slower... Usually has only one...
an ion channel opens the channel, allowing ions to flow into or out of the cell action response binding sites
single protein receptor-coupled G-protein in two parts and induces biochemical changes actions response binding site
