Weeks 1-3 Flashcards
What makes up the CNS and PNS?
CNS: Brain and spinal cord
PNS: Afferent and efferent nerves.
The cell that transmits signals from sensory neurones to motor neurones is _____
Interneurone
What do excitatory neurones do and what is the most common NT involved.
Increase activity of target cells.
NT = glutamate.
What do inhibitory neurones do and what is the most common NT involved.
Decrease activity of target cells.
NT= GABA
What is the function of schwann cells?
Myelination in PNS
What is the function of oligodendrocytes?
Myelination in the CNS
What is the function of astrocytes?
Provide nutrients for repair and scarring process.
What is the role of microglia?
Immune cells of the CNS
Define tract
A group of functionally related axons in the CNS
Define nerve
A bundle of axons in the PNS
Define ganglion
A collection of neuronal cell bodies in the PNS.
Define nucleus (CNS)
Collection of neuronal cell bodies in the CNS
What makes up the autonomic nervous system.
Sympathetic and parasympathetic
Describe organisation of sympathetic NS.
Myelinated short pre ganglionic neurone. Ach binds to nicotinic receptor in ganglion (close to CNS). Long post ganglionic neurone releases noradrenaline.
Describe the organisation of the PARAsympathetic NS.
Long myelinated pre ganglionic neurone. Ach binds to nicotinic receptor in ganglion (close to or in target). Short unmyelinated post ganglionic neurone releases Ach which binds to muscarinic receptors.
How does the baroreflex work?
Baroreceptors detect changes in the mean arterial pressure. Negative feedback involves the sympathetic or parasympathetic to reverse the change.
The enteric NS
Works autonomously to control GIT activity.
The myenteric plexus receives autonomic innervation from the sympathetic and parasympathetic NS
What 3 structures make up the forebrain?
Cerebrum
Thalamus
Hypothalamus
What 3 structures make up the hindbrain? And what is its function?
Pons
Medulla Oblongata
Cerebellum
Reticular formation aid with autonomic functions.
Copus callosum
Connects the two hemispheres.
Raphe nuclei
In the medulla and midbrain, contains 5-HT cells.
Area postrema
Found in pons and medulla. Contains the CTZ/chemoreceptor trigger zone (vomiting)
Locus coeruleus
Found in pons, contain noradrenaline positive cells.
Substantia nigra
Midbrain
Motor system, dopamine containing cells.
Projects to basal ganglia
Superior colliculus
Midbrain
Receives visual inputs and brings eyes to focus of attention.
Periaqueductal grey matter
Midbrain
Control of somatic (emotive) pain and fear
Red nucleus
Midbrain
Motor control structure
Cerebrum/Telencephalon (components and function)
Cerebral hemisperes, basal ganglia, hippocampus, amygdala.
Motor control
Limbic system/Diencephalon (components and function)
Mood and emotion and homeostasis
Consists of hippocampus, amygdala, hypothalamus, basal ganglia, mammillary bodies.
Frontal lobe role
Control of movements
Parietal lobe role
Somatosensory
Temporal lobe
Hearing, learning, memory, emotion
What 3 membranes cover the CNS? (PAD)
Pia matter (inner)
Arachnoid
Dura (outer)
Define electrical gradient
Flow of ions to opposite charge
Define concentration gradient
Force driving an from region of greater concentration to lesser concentration of itself
3 main channel proteins
Ligand gates (chemical)
Voltage gated (voltage)
Stretch activated (mechanically)
What four factors contribute to the resting potential
1) Charged intracellular proteins (neg-)
2) Na/K pump
3) K+ ions
4) Na+ ions
What does the sodium potassium pump do?
3 Na+ out.
2 k+ in.
Inside negative.
How permeable is the membrane to K+ and Na+?
Freely permeably to K+
Slightly permeable to Na+
Define equilibrium potential (E-ion)?
The electric potential difference that balances the ionic concentration gradient
Define ionic driving force (equation)
Membrane potential (Vm) - Equilibrium potential (E-ion)
What does the Nernst equation calculate?
Equilibrium potential (E-ion) but NOT resting membrane potential
Why is the Nernst equation insufficient to calculating the resting membrane potential?
Na+ flow into cell at rest too. Therefore resting potential not equal Ek.
Needs to take into account flow of Na+ ions
What does the GHK equation calculate?
Membrane potential
