1. Introduction to the Nervous System Flashcards
1
Q
The nervous system
A
a communication and control network that allows an organism to interact with its environment
2
Q
General functions of nervous system
A
Sensory detection, information processing, and the expression of behaviour
3
Q
Central nervous system (CNS)
A
Brain and spinal cord
4
Q
Peripheral nervous system (PNS)
A
Afferent/sensory division and efferent/motor division
5
Q
Afferent division
A
The sensory system, generates input to the CNS
6
Q
Efferent division
A
Receives output from CNS, to the somatic nervous system and autonomous nervous system.
7
Q
Somatic motor system
A
Efferent division of PNS that stimulates skeletal muscle activity
8
Q
Autonomic nervous system
A
Efferent division of the PNS that includes the sympathetic division, parasympathetic division, and enteric nervous system.
9
Q
Enteric nervous system stimulates…
A
Intestinal muscle wall, mucosa
10
Q
Sympathetic division stimulates…
A
Smooth and cardiac muscle, glands
11
Q
Parasympathetic division stimulates…
A
Smooth and cardiac muscle, glands
12
Q
Components of the Nervous System
A
neurons, neuroglial cells, blood vessels, connective tissues
13
Q
Soma
A
Factory of the neuron
14
Q
Dendrite
A
Input transmission of neuron
15
Q
Axon
A
Output transmission of neuron
16
Q
Nissl bodies
A
A Nissl body is a large granular body found in neurons. These granules are of rough endoplasmic reticulum (RER) with rosettes of free ribosomes, and are the site of protein synthesis.
17
Q
Predominate neuron shape in invertebrates
A
Unipolar
18
Q
Predominate neuron shape in vertebrates
A
Multipolar
19
Q
Bipolar neuron example
A
Dorsal root ganglia cells
20
Q
Pseudounipolar neuron example
A
Retinal cells, olfactory epithelium cells (unmyelinated, no dendrites)
21
Q
Multipolar neuron example
A
Interneurons, motor neurons
22
Q
Traditional senses
A
Sight, hearing, smell, taste touch
23
Q
Non-traditional senses
A
Nociception (tissue damage), equilibrioception (balance, coordinate movements), proprioception (know the body parts and positioning), and thermoception (temperature changes)
24
Q
What do sensory receptors do?
A
Convert a stimulus into neuronal activity
25
What type of neurons constitute 90% of all neurons?
Interneurons
26
What type of neurons constitute 9% of all neurons?
Motor neurons
27
What type of neurons constitute 0.9% of all neurons?
Sensory neurons
28
Sensory neurons
Afferent neurons
Bipolar
Sense detection by sensory receptors on receptor cell, transmitted down myelinated axon
29
Motor neurons
Efferent neurons
Multipolar
Initial signal recieved by dendrites
Axon terminals act on muscles at neuromuscular synapse
30
Interneuron
Association neuron
Multipolar
Cell body, dendrites, axon terminals
Unmyelinated
31
Why does shingles (caused by herpes zoster) affect the skin after many years latency?
Reactivated herpes zoster is transported along the sensory axons to the skin.
32
What's the consequence of interruption? Such as cancer drugs
Neurodegeneration
33
Fast axonal transport
Membrane-bound organelles and mitochondria
34
Slow axonal transport
Proteins
35
Anterograde axonal transport
From the soma toward the axonal terminals, kinesin
36
Retrograde axonal transport
From the axonal terminals toward the soma, dynein
37
Axonal transport depends on what? Describe the mechanism of this.
The movement of transport filaments. This requires energy supplied by glucose. Mitochondria controls the level of cations in the axoplasm by supplying ATP to the ion pumps. An important cation for axonal transport is Ca2+. Transport filaments move along the cytoskeleton (microtubules [M] or neurofilaments [NF]) by means of cross-bridges. Transported components attach to the transport filaments. CaBP, Ca2+-binding protein; NF, neurofilaments.
38
Role of supportive matrix of the CNS
Provides local environment suitable for neurons to function
39
What are the components of the local environment?
Neuroglia, CNS circulation, the blood-brain barrier (BBB), the cerebrospinal fluid (CSF)
40
What are the major roles of the supportive matrix in neurotransmission?
Taking up neurotransmitters; providing myeline sheaths
41
Neuroglia in the CNS
Astrocytes, oligodendroglia, microglia, ependymal cells
42
Astrocytes
Structural support, metabolic support; neurotransmiitter uptake and release; ion homeostasis; nervous system repair; synaptic plasticity.
43
Oligodendroglia
Myelination
44
Microglia
Immune defense
45
Ependymal cells
Production of the CSF
46
Neuroglia in the PNS
Satellite cells and Schwann cells
47
Satellite cells
Function similar to astrocytes
48
Schwann cells
Myelination (debris clearances, nerve regeneration). Can be myelinating or nonmyelinating.
49
Myelin
Ensures fast saltatory conduction of AP.
CNS: oligodendroglia, a single cell myelinates many axons
PNS: Schwann cells, a single cell myelinates only one axon
50
What cells can give rise to brain tumors in the adult brain?
Astrocytoma, oligodendroglioma, ependymoma.
| In babies and infants: neuroblastomas.
51
Features of neurons
Post-mitotic
Dendrites and axons
Excitable
Functional units of nervous tissue
52
Features of neuroglia
Mitotic
No branches
Non-excitable
Supporting cells of nervous tissue
53
Why does the gray matter have a higher metabolic rate?
The gray matter contains soma which is the factory of the neuron.
54
Gray matter
Soma and dendrites (axons, glial cells, capillaries)
55
White matter
Axons (glial cells, capillaries)
56
Diencephalon
The thalamus and hypothalamus
57
Cerebrum
Frontal lobe, temporal lobe, parietal lobe, occipital lobe
58
Brain stem
Midbrain, pons, medulla
59
Location of medulla
The rostral extension of the spinal cord (lowest)
60
Location of pons
Rostral to the medulla (just above the medulla)
61
Location of midbrain
Rostral to the pons
62
Ten cranial nerves functions
```
Eye movement
Head movement
Facial expression
Swallowing
Taste
Hearing
Sensory
Motor
Autonomic functions of viscera (glands, digestion, heartrate)
```
63
Functions of the brain stem in general
Autonomic centers and relay nuclei
64
Function of medulla
Breathing, blood pressure, swallowing, coughing, vomiting
65
Function of pons
Balance and posture, breathing
66
Function of midbrain
Micturition (urinary reflex), eye movements, auditory and visual systems
67
Cerebellum location
Between the cortex and the spinal cord, attached to the brain stem and lies dorsal (behind) to the pons and medulla
68
Cerebellum functions
Coordination of movement, maintenance of posture and balance
69
Thalamus and hypothalamus location
Between the cerebral hemispheres and the brain stem, so called diencephalon ("between brain")
70
Functions of the thalamus
Processes sensory information going to the cerebral cortex and motor information coming from the cerebral cortex to the brain stem and spinal cord
71
Functions of the hypothalamus
Regulates body temperature, food intake, and water balance, and controls the hormone secretions of the pituitary gland (anterior pituitary hormones, antidiuretic hormone, oxytocin)
72
Cerebrum location
```
The anterior (front) portion of the brain
Divided into left and right hemispheres connect by the corpus callosum
The cerebral hemispheres consist of the cerebral cortex (grey matter), an underlying white matter, and three deep nuclei (basal ganglia, hippocampus, amygdala)
```
73
Cerebrum functions
Perception, higher motor functions, cognition, memory, emotion
74
Gyrus vs Sulcus
A gyrus is a ridge on the cortex, a sulcus is a groove
75
Fissure
A fissure is a larger furrow than a sulcus, that divides the brain into hermispheres
76
Sylvian/lateral fissure
separates the frontal and parietal lobes of the brain from the temporal lobe.
77
Transverse fissure
Horizontal fissure found between the cerebrum and the cerebellum
78
Longitudinal fissure
Separates hemispheres
79
Three areas of cerebral cortex
motor areas, sensory areas, and association areas
80
Functions of cerebral cortex
Receives and processes sensory information and integrates motor functions
81
Relative size of areas of cerebral cortex
Sensory and motor areas make up ~1/5 of the cortex, and the association cortex makes up most of the cortical surface.
82
Roles of cerebral cortex parts
Sensory and motor areas are directly involved in sensory or motor processing. The association cortex analyzes the incoming information and translates it into something meaningful (perception)
83
Motor cortex location
Frontal lobe
84
Auditory cortex location
Temporal lobe
85
Sensory cortex location
Parietal lobe
86
Visual cortex location
Occipital lobe
87
Olfactory and gustatory cortex location
Frontal lobe
88
Neuron v ganglion
A group of neurons in the CNS and in the PNS, respectively
89
Location of basal ganglia
Base of forebrain
90
Location of hippocampus
In the temporal lobe
91
Location of amygdala
In the temporal lobe
92
Function of basal ganglia
Movement (parkinsons, huntingtons)
93
Function of hippocampus
Memory
94
Function of amygdala
Emotion
95
Ventricles
In the brain: two lateral ventricles, the third ventricle, and the fourth ventricle
96
Foramina
Interventricular foramina and cerebral aquaduct
97
Cerebrospinal fluid (CSF)
Liquid that fills and circulates within the ventricular system of the brain
Produced by the choroid plexus
CSF sampling: lumbar puncture (lumbar cistern)
98
Functions of ventricular system and CSF
Distribute nutritive materials to and removes wastes from nervous tissue; protection of the brain
99
Hydrocephalus
An abnormal accumulation of CSF in the ventricles
100
Why brain infections are difficult to treat?
Antibodies too big to cross the BBB
101
Why can radiologists exploit brain tumors by introducing substance into the circulation?
Brain tumors cause the disruption of the BBB, which leads to leakage of radiolabelled substance into the region occupied by the brain tumor
102
How is the BBB formed
By capillary endothelial cells, which are connected by tight junctions, and astrocytes.
103
What can cross the BBB
The BBB only allows the passage of water, some gases (oxygen, carbon dioxide), and some ions by passive diffusion; a few water-soluble substances (glucose and amino acids) by active transport; lipid-soluble substances.
104
What are the functions of the BBB
Protect the brain from bacterial infections, and damage by neurotoxic molecules (neurotoxins).
105
Location of spinal cord
The most caudal portion of the CNS; extend from the base of the skull to the first lumbar vertebra; lies within the bony vertebral column.
31 pairs of spinal nerves: cervical (8), thoracic (12), lumbar (5), sacral (5), coccygeal (1)
106
Functions of spinal cord
Contain both afferent and efferent nerves
Ascending pathways: carry sensory information from the periphery to higher levels of the CNS
Descending pathways: carry motor information from higher levels of the CNS to various organs
The "information highway of the body“ to connect the various organs of body to the brain.
107
Reflex arc
The simplest type of neural circuit, e.g. "withdrawal flex"
Nocioceptors detect pain, propagates through dorsal root to interneurons, which feedback to motor neurons through the ventral root, to act at neuromuscular junction and pul away.
108
Degeneration
Chromatolysis, wallerian degeneration
109
Regeneration
In the PNS, not CNS
110
Axon growth
Trophic factors (NGF, neurotrophin, CNF)
