Nervous System Flashcards
(84 cards)
1
Q
Astrocyte
A
Ensheath synapses, regulate excitability, synaptic transmission, secretes ECM, involved in neurogenesis and cell migration
1
Q
Microglia
A
Highly motile phagocytic scavenger, responsive to injury, infection, and electric activity
2
Q
Ependymal cell
A
lining on the ventricles and central canal, production of cerebrospinal fluid (CSF), rich in mitochondria and microvilli
3
Q
Oligodendrocyte
A
provides myelin, exert axonal metabolic support
4
Q
Satellite
A
assist in regulating the external chemical environment, synaptic transmission, and excitability, secrete ECM, involved in cell migration, are very sensitive to injury and may exacerbate pathological pain
5
Q
Schwann cell
A
provides myelin, axonal metabolic support, axonal pathfiniding during nerve development and regeneration, production of the ECM that forms the endoneurium, modulation of neuromuscular synaptic activity, and presentation of antigens to T-lymphocytes.
6
Q
Unipolar associates with…
A
Sensory ganglia
7
Q
Unipolar structure
A
Has a round soma and one single neurite
8
Q
Bipolar structure
A
Has oblong soma and two neurites
9
Q
Afferent/Sensory Division and Function
A
Somatic vs. Visceral
Transmits AP from the periphery (body) to the CNS
10
Q
Efferent/Motor Division and Function
A
Carries action potentials away from the CNS towards the periphery (body)
11
Q
Autonomic nervous system
A
Subdivision of efferent motor involuntary control: sympathetic and parasympathetic
12
Q
Sympathetic
A
Process the body’s fight-or-flight response
13
Q
Parasympathetic
A
Process the body’s “rest-and-digest” response
14
Q
Describe neurons
A
- Long axons
- Vertebrate axon are insulated with myelin composed of oligodendrocytes in CNS and Schwann cells in PNS
- Rapid conduction of electrical signals
- Unidirectional manner
15
Q
Describe neuronal synapses
(Pre/Post/Space)
A
- Presynatic axonal terminal has membrane vesicles containing neurotransmitters.
- Postsynaptic dendrites in form of dendritic spines containing receptors.
- Aqueous space in between allow diffusion of water soluble neurotransmitter.
16
Q
Describe neuronal spines
A
Composed of:
- receptors of neurotransmitters and neuromodulators (NMDAR, AMPAR)
- Proteins stabilize synaptic architect
- Postsynaptic density has signaling proteins.
17
Q
Neutro:astrocytes ratio?
A
1:1 - 1:4
18
Q
From glycolysis, what product is the key intermediate metabolite to make glutamate?
A
alpha-ketoglutarate from Krebs cycle
19
Q
How can alpha-KG convert to glutamate?
A
By putting in NH2 which is a by-product when alanine is converted to pyruvate (which is for Krebs cycle)
20
Q
What can glutamate converted into?
A
- alpha-KG (by GDH)
- vesicular glutamate (VGLUT)
- GABA
- Glutathione/protein
- Glutamine* (form loop to convert back to glutamate)
21
Q
Difference between glutamate and GABA
A
Glutamate is excitatory, GABA is inhibitory
22
Q
What amino acids glutamate derived from?
A
Glucose, alanine, and glutamine
23
Q
Describe nerve terminal in glutamate neurotransmission?
A
- Composed of synaptic vesicles with glutamate transporters; mitochondria with glutaminase (break down glutamine to form glutamate); metabotropic glutamate receptor (to enhance neurotransmission); glutamate transporter (EAAT2); glutamine transporter (SA).
24
What components are on dendritic spine in glutamate neurotransmission? (receiving end)
- Glutamate receptors (AMPA and NMDA)
- Glutamate transporters (EAAT 3/4)
25
Describe surrounding astrocyte in glutamate neurotransmission?
- Glutamate (EAAT 1 and 2) and Glutamine (SN) transporter.
- Glutamate converted to glutamine before exiting astrocytes.
26
Describe biophysical properties of synaptic AMPA and NMDA receptors
(Think of the wave graph)
EPSC = brief fAst AMPA + prolonged slow NMDA
(EPSC = excitatory postsynaptic currents)
27
Compare ionotrophic vs. metabotrophic of glutamate signaling
- Iono: NMDA, AMPA, Kainate = ligand-gated ion channels
- Meta: IP3 + CA2+ for excitatory; cAMP for inhibitory = G-coupled proteins.
28
Describe GABA shunt
- GABA-T (t = transaminase) removes GABA by directly forming succinic samialdehyde (SSA) via transamination with alpha-KG, which also reforms glutamate.
- GAD + glutamate produces GABA and CO2
- Succinic (SSA) is oxidized by nad AND SSA dehydrogenase (SSADH) to NADH+ and succinate (re-enter Krebs cycle).
29
Describe donut model of GABA(A)
- Five subunit (alpha-beta-alpha-beta-gamma)
- Five subunit interfaces (1-5)
- Ligand binding pockets for GABA and benzodiazepine
- Peptide loops (A-E) at subunit interfaces allowing GABA to bind.
- Pore in the center represents Cl- channel.
- Loops are homologous
- Requires GABA binds first, then BZ facilitates/enhances the effect.
30
Describe function of GABA(b) receptors
- Metabotropic receptors with STRONG dimers.
- Stimulate opening of K+ channels for K+ to flow OUT (post-synaptic)
- Cause HYPERpolarizing of neurons.
- PREVENT opening of sodium channel and calcium channels (VDCC) [in presynap] and ultimately firing AP.
- Stop neurotransmitter release
- Decrease cAMP activity
31
Difference dorsal root ganglion vs. Ventral root?
Sensory goes dorsal, motor goes ventral
32
Principle of divergence?
1 neuron to communicate with many other neurons .
- Parasympathetic: 1:4
- Sympathetic: 1:20
33
Principle of convergence?
1 neuron to RECEIVE input from many neurons
- Sympathetic > Parasympathetic
34
What's tonic control?
- State of continuous activity. Both divisions are active.
- Effector organ receive competing inputs from sympathetic and parasympathetic divisions.
35
What does visceral sensory neurons do?
They respond to stretching, temperature, chemical changes, irritation and pain (from viscera, glands, blood vessels)
36
What route does visceral sensory neurons transmit information through?
general visceral afferent
37
Collections of nerve cell bodies inside the PNS are called
ganglia
38
The parasympathetic nervous system influences function in all of these organs except? (adrenal glands, heart, pupillary smooth muscles, salivary glands)
Adrenal gland (remember, adrenaline!)
39
Paravertebral or sympathetic chain ganglia contain the cell bodies of what kind of neurons?
Sympathetic postganglion neurons
40
Some of the nerves that innervate the lymph nodes have been determined to be adrenergic suggesting that the ______ may influence lymph node activity.
Sympathetic system
41
Prevertebral ganglia contain the cells bodies of which kind of neurons?
Postganglion sympathetic neurons
42
The synapse between the preganglionic and postganglionic neuron in the parasympathetic nervous system is found in ...?
Terminal or intramural ganglia
43
Mydriasis is the physiological action of dilation of the pupil which is under the control of ____ inervation.
Sympathetic
44
Autonomic innervation of the heart
The heart is innervated by both the sympathetic and parasympathetic nervous systems and they have opposite effects on the heart.
45
The autonomic outflow from the lumbar segments of the spinal cord contains ____ neurons whereas the sacral spinal cord contains ____ neurons.
Sympathetic preganglionic // Parasympathetic preganglionic
46
Sequence of a typical reflex arc?
Receptor -- afferent neurons --- interneurons -- efferent neurons -- effector (tough a hot plate!)
47
Activity of facial nerves (#7)
salivation, lacrimation
48
Activity of glossopharyngeal nerve (#9)
chemoreception, baroreception, swallowing and salivation
49
Activity of oculomotor (#3)
Pupillary constriction and accommodation
50
Activity of sacral
Bladder constriction, erection of external genitalia
51
Activity of vagus (#10)
visceral sensation, chemoreception, baroreception, control of parasympathetic centers
52
A state of continuous activity is referred as
Tonic
53
The secretion of the adrenal medulla act to supplement the effects of the ______.
sympathetic stimulation
54
Where would you not find a cholinergic nicotinic receptor?
Parasympathetic target organs (because it has mAChR)
55
Effects of the sympathetic division (FIGHT AND FLIGHT!) include all EXCEPT
increase motility of the viscera
56
Control of temperature, endocrine activity, and thirst are functions associated with the _____.
Hypothalamus
57
Sympathetic responses generally are widespread because ____.
NE and epinephrine are secreted into the bloodstream
58
The route of MAJOR parasympathetic outflow from the head is via the _____.
vagus nerve
59
Alpha and beta receptors are classes of ______ receptors.
adrenergic
60
Cholinergic receptors are either nicotinic or ______.
Muscarinic
61
The parasympathetic division uses only ______ as a neurotransmitter.
acetycholine
62
NE and epinerphrine are ______ secreted by the medulla of the adrenal glands.
catecholamines
63
The _____ respond to stretching, temperature, chemical changes, irritations and pain from viscera, glands, and blood vessels.
visceral sensory neurons
64
The response of the visceral reflex arc is produced by preganglionic fibers emerging from spinal cord's _____.
Lateral horn
65
Autonomic ganglia are ____ ganglia made up of cell bodies of multipolar neurons, whereas dorsal root ganglia are ____ ganglia of unipolar neurons.
motor (efferent) /// sensory (afferent)
66
The _____ ganglia are located within the walls of the target organ.
intramural
67
What is RAS?
Reticular Activating System - important for complex network of interconnected nuclei throughout the brainstem that govern basic functions of somatic (premotor), cardiovascular, pain, sleep, habituation.
68
Components of meninges
Dura mater, arachnoid mater (with trabeculae, space and villi), pia mater
69
CSF production
Choroid plexus
70
Location of CSF circulation?
subarachnoid space
71
CSF absorption
Venous sinuses, arachnoid villi
72
Pathway of CSF circulation
Lateral ventricle - foramen monro (4 mens in a row) - 3rd ventricle - aqueduct of Sylvius (thin woman named Sylvia) - 4th ventricle - Median Magendie to Central canal to subarachnoid OR Lateral Luschka to subarachnoid space - arachnoid villi - dorsal sagittal sinus
73
Hydrocephalus (congenital)
Malformations interfere with CSF flow causing expansion of ventricular system. Most common stenosis of aqueduct of Sylvius.
74
Hydrocephalus (acquired)
- Neoplasia
- Inflammation (FIP)
- Dural fibrosis
- Occipital bone hypoplasia
75
Characteristics of CSF
(High/low values)
High % of water and Cl- value; equal Na+ and Osmolarity, the rest is low.
76
Ependymocytes
- Rich in mitochondria
- Linked to by desmosomes
- Apical microvilli and cilia
- Basal membrane infoldings
77
Tanycytes
- Located at 3rd ventricles
- Linked by tight junctions
- Apical microvilli, one or no cillium
- Basal membrane protrusions contact blood vessels and hypothalamic neurons
78
Blood-CSF barrier. Location? Ultrafiltration? Clinical implication?
1) L: choroidal epithelial cells, pial endothelium and basal membrane
2) U: restrictive passage from blood to CSF.
3) C: higher protein content
79
Arachnoid-CSF barrier. Location? Ultrafiltration? Clinical implication?
L: arachnoid villi and venous sinus.
One-way valve, flow from arachnoid space to venous sinus
Clinical: external hydrocephalus
80
Blood brain barrier. Location? Ultrafiltration? Clinical implication?
L: neurovascular unit brain microvascular endothelium, pericyte, astrocytic end-feet and basal lamina
C: antibodies, antibiotics, many drugs and contrast agent cannot cross BBB.
81
What is the cortex?
The outer zone of neural tissue that contains neuronal cell bodies or somata, organized in layers of laminae - cerebral and cerebellar
82
What is nucleus? nuclei?
Cluster of neuron (gray matter) with similar or related function located deep into cerebral hemispheres and brainstem.
83
Tract or fibers
Bundles of axons
