Lecture 1 Flashcards
1
Q
Nervous System
A
broken down into two main parts Centeral Nervous System and Peripheral nervous system
2
Q
Central Nervous system is?
A
Brain and spinal cord. Overall control center, convering objective stimuli into subjective perceptions and sensations.
Translates the “plan” for behavioral responses such as grasping, swimming, or smiling into directions that drive behavioral responses.
3
Q
Peripheral nervous system is broken down into what?
A
Autonomic nervous system - sympathetic and parasympathetic divison
Somatic nervous system- sensory (afferent) and motor (efferent)
4
Q
Parts of the CNS
A
Cerebrum
-Cortex
-Internal structures
Diencephalon
-Thalamus
-Hypothalamus
Brainstem
-Midbrian
-Pons
-Medulla Oblongata
Cerebellum
Spinal Cord
5
Q
Rostral
A
towards the front, or beak/nose
6
Q
Caudal
A
Towards the back or tail
7
Q
Dorsal
A
Toward the top (or back of spinal cord)
8
Q
Ventral
A
Towards the bottom (or front of the spinal cord)
9
Q
Horizontal/Transverse plane
A
divides the body into upper and lower halves
10
Q
Coronal/Frontal Plane
A
divides the body into front and back sections
11
Q
Sagittal plane (longitudional)
A
Divides the body into left and right sides.
12
Q
What is gray matter compsed of? what is its function?
A
is compsed of the neurons and glia and the connections between neurons
where information processing of the brain occurs
Ouside in brain and inside in the spinal cord
13
Q
What is white matter composed of and what is its function?
A
is compsed of axons carrying information between parts of the nervous system
Inside in the brain and outside in spinal cord.
14
Q
What is meningitis?
A
Inflamed or infected meninges
Can be life threatening because the inflammation within the enclosed cranial cavity puts pressure on the brain.
15
Q
What is encephalitis
A
Conditon when the pathogen gets through the pia matter and infects the brain tissue directly
16
Q
What are meningies?
A
Dura mater
Arachnoid mater
Pia mater
17
Q
Hemato means
A
Blood
18
Q
oma means?
A
tumor/mass
19
Q
Extradural Epidural hematoma?
A
Rapidly expanding hemorrhage under arterial pressure peels the dura away from the inner surface of the skull, forming a lens-shaped biconvex hematoma that often does not spread past the cranial sutures where the dura is tightly apposed to the skull.
20
Q
Subdural hematoma
A
are typically crescent shaped and spread over al arge area. Density depends on the age of the blood. Acute blood is hyperdense and bright on CT. After 1-2 weeks the clot liquifies and may appear isodense.
21
Q
Where in relation to menigeal layers is epidural anethesia administered?
A
outside of the dura –> not puncturing meninges
22
Q
CNS - spinal cord does what?
A
Conduit for the transmitting ascending sensory information and descending motor information to/from the brain.
Processes sesnory information from the limbs, trunk, and internal organs
Controls body movements directly
Regulates many visceral functions
23
Q
What is the PNS somatic nervous system composed of?
A
nerves and collections of cells within ganglia
24
Q
What is peripherial neuropathy?
What are some causes and symptoms?
A
Sansory nerve damage:
-unusual sensations
-burning
-numbness
-tingling
- balance problems
Motor nerve damge
-muscle cramping
-twitching
-reflx abnormalities
25
PNS - somatic nervous system
Acts as the interface between the CNS and the world in relation to the body
Monitors the condition of the body internally and externally and affects behavioral changes in response to those conditions
26
PNS - autonomic nervous system
Regulates the visceral organs, vasculature, and glands
Consists of sympathetic and parasympathetic divisions
Divisions function in harmony
27
Two major cell types in the nerous system
Neurons - signaling cells
Glia - support cells
28
Parts of neurons
Cell bodies
Axons
dentrites
29
Roles of the parts of the neruon
Cell body, axons, dentrites
Cell body- receives many direct imputs
Axons- transmits signals, generate and conduct action potentials
Dentrites- receive inputs from axons via synapses
30
Neurons classificaiton by morphology
Unipolar- smooth muscle
Pseudo-unipolar - some sensory information
Bipolar- retina
Multipolar - most common
31
What are the 3 types of multipolar cells?
motor neuron of spinal cord
pyramidal cells of hippocampus
purkinje cells of cerebellum
32
Neurons classification by function
Sensory (afferent)
Motor (efferent)
Interneuron
33
What are afferent signals
sensory, dorsal
34
What are efferent signals
motor, ventral
35
Sensory Neurons
Primary (1st order)
Secondary (2nd order)
Tertiary (3rd order)
36
Primary (1st order)
Carry signals from the peripheral receptor to the spinal cord or medulla
37
Secondary (2nd order)
Carry signals from the spinal cord or medulla to the thalamus
38
Tertiary (3rd order)
Carry the signals from the thalamus ro the primary sensory cortex
39
Motor neurons
Upper motor neurons or Lower motor neurons
40
Upper motor neurons
completely in the CNS
Cell bodies in the cortex or brainstem synapse with lower motor neurons
41
Lower motor neurons
part of neuron is in the CNS and the part of the neuron is in the PNS
Cell bodies in the spinal cord or brainstem axons form spinal and cranial nerves
42
Glia of CNS
43
Astrocyte
| remember conencts cell body with blood vessel
helps from the blood-brain barrier
regulates interstitial fluid composition
provides structural support and organization to the CNS
Assists with neuronal development
replicates to occupy space of dying neurons
44
Ependymal cell
lines ventricles of brain and central canal of spinal cord
assists in production and circulation of CSF
45
Microglial cells
Phagocytic cells that move through CNS
Protects the CNS by engulfing infectious agents and other potential harmful substances
| Phagyoctic cells clean up duty, killing bad stuff
46
Oligodendrocyte
myelinates and insulates CNS axons
allows faster action potential propagation along axons in the CNS
47
Glia of PNS
48
Satelite cell
Electrically insulates PNS cell bodies
Regulates nutrient and waste exchange for cell bodies in ganglia
49
Schwann cell
surrounds and insulates PNS axons and myelinates those haveing large diameters
allows for faster action potential propagation along an axon in the PNS
50
Astrocytoma
type of cancer that can form in the brain or spinal cord; originates from astrocytes; most common adult brain tumors
51
Glioblastoma
is the most maligant, aggressice and common form of astrocytoma; very abnormal-appearing cells, proliferation, areas of dead tissue and formation of new vessels, pronounced brain invasion and destruction, very fast progression.
52
Neurotransmitters of the CNS
are found throughout the CNS
are not specifically inhibitory or excitatory
action of neurotransmitters dependent upon the receptor or the pathway that is activated
53
Glutamatergic Neurons
Glutamate
Majority produce an excitatory response
| Both this and gabaergic neurons make up about ~ 90% of NT in the CNS
54
GABAergic nerons
y-aminobutyric acid
majority produce and inhibitory response
55
Glycinergic neurons
glycine
majority produce an inhibitory response
56
Cholinergic (acetylcholine)
Can produce excitatory, inhibitory, or modulatory responses in CNS
Excitatory neurotransmitter in PNS
57
Noradrenergic (Norepinephrine)
Can produce excitatory, inhibitory, or modulatory responses in CNS
58
Adrenergic (Epinephrine)
Can produce excitatory, inhibitory, or modulatory responses in CNS
59
Dopaminergic (Dopamine)
Can produce excitatory, inhibitory, or modulatory responses in CNS
60
Serotonergic (serotonin)
Can produce excitatory, inhibitory, or modulatory responses in CNS
61
Neurotransmitter-Drug therapies
Drugs acting on the CNS primarily impact the synapse, increasing or decreasing neurotransmitter release or blocking reuptake or neurotransmitter into the synaptic terminal
62
Caffine increases __ levels in the brain promoting alertness.
glutamate
63
Benzodiazepines and barbiturates enhance __ , receptor fucntion, causing sedation.
GABA
64
Locally injected botox blocks the release of __ to reduce the muscels ability to contract
Ach
65
What are ventricles
labyrinth of CSF-filled cavities that serve various supportive fucntions
66
How many ventricles are there?
2 lateral one in each cerebral hemisphere
Third ventricle in the diencephalon
Fourth ventricle between the brainstem adn cerebellum
67
What is CSF
cerebral spinal fluid - clear, colorless fluid; a mixture of water, protiens at low concentrations, ions, neurotransmitters, and glucose
68
Where is CSF found?
occupies the ventricular system, the cerebral and spinal subarachnoid spaces, and the perivasular spaces in the CNS
69
What does CSF do?
Serves to support the CNS to cushions and protect it from physical shock and trauma.
Helps to remove waste and deliver nutrients
70
What produces CSF?
choroid plexus
71
CSF is produced by a modified vasular structure called the __ which is present in each of the 4 ventricles
Chordae plexus
72
Bulk flow of CSF
Lateral ventricles --> third and fourth ventricles, outward from the basal foramina, upward around the brainstem --> both the convexities of the hemispheres and downward to spinal subarachnoid space
73
CSF can be used diagnostically
Since it "bathes" the central nervous system, CSF can pick up chemicals and impurities in the brain and spinal cord
Analyxing it for bacteria, white blood count, glucose levels, protien, or abnormal cells can help identify specific diseases in the CNS
74
Hydrocephalus and Increases intracranial pressure
Inability of the body to absorb cerebrospinal fluids correctly; can also be a result of a narrow channel between bentricles which hinders the proper flow of the fluid
75
Ventriculoperitoneal shunt for hydrocephalus
76
What is the name of the tissue that secretes cerebrospinal fluid?
1. Ventricular tissue
2. Choroid plexus
3. Pia mater
4. Dural Sinus
2. Choroid plexus
77
What is the name of the passageway between the third and fourth ventricles?
1. The foramen of magendie
2. The interventricular foramen
3. The cerebral aqueduct
4. The central canal
3. The cerebral aqueduct
78
Arterial system of the CNS
Brain vasulature disorders constitute a major class of CNS disease
The principle source of nourshment for the CNS is glucose, and oxygen is necessary for cell fucntion
Brain functions become severly disrupted when the blood supply of the CNS is interrupted, even briefly
79
Brain vasculature is closely related to the ventricular system and CSF .
Most CSF is produced continually by the choroid plexus via active secretion of ions from blood plasma
To contain a constant brain volume CSF is returned to the blood through valves between the subarachnoid space and the dural sinuses
80
Two arterial systems
1. anterior (carotid) circulation - fed by internal cariotid arteries
2. Posterior (vertebral-basilar) circulation - fed by vertebral arteries
are not indpendent, but are connected by anastomotic (interconnected) networks of arteries
81
Paths for collateral blood supply
The diencephalon, midbrain and cortical surface receive blood from anterior and posterior circulations.
The brainstem receives blood only from posterior circulation. (pons and medulla, and cerebellum)
The spinal cord receives blood from vertebral arteries and systemic circulation, which also supplies muscle, skin, and bones.
82
Circle of Willis
is an example of a network of interconnected arteries
communication between anterior and posterior circulation is valuable because decreased flow in one system can be compensated by increased flow in the other
83
Nervous System Development
84
What are the two parts of the prosencephalon (forebrain)?
- telencephalon
- diencephalon
85
What structures make up the telencephalon?
- cerebral hemispheres
- cerebral cortex
- subcortical white matter
- basal ganglion
- basla forebrain nuclei
86
What structures make up the diencephalon
- thalamus
- hypothalamus
- epithalamus
87
What structures make up the mescencephalon (midbrain)?
- cerebral peduncles
- midbrain tectum
- midbrain tegmentum
88
What are the two structures that make up the rhombencephalon (hindbrain)?
- metencephalon
- myelencephalon
89
What structures are apart of the metencephalon (hindbrain)?
- pons
- cerebellum
90
What structure makes up the myelencephalon?
medulla
91
Overall embrynology
The body and all its structures arise from three embryonic tissue layers
Endoderm
Mesoderm
Ectoderm
92
What is formed from the ectoderm?
- skin
- neurons
93
talk about the development of the nervous system starting with the neural plate
- the neural plate is developed from a specialized portion of ectoderm
- the neural plate then forms a tubelike structure - the NEURAL TUBE- which the neurons and glial cells are derived
- the neural tube walls form teh CNS adn teh cavity forms the ventricular system which contains CSF
94
the periphereal nervous system is formed from?
the neural crest
95
what stimulates formation of the neural plate?
notochord
96
a specialized set of neurons differentiatse into the ________ ________ _________, which will generate the neurons of the PNSNeural tube walls
neural crest cells
97
what closed forming the neural tube?
neural groove
98
once the neural groove closes and forms the neural tube, the nueral crest cells have differentiated into sensory cells of what?
of the doral root ganglia
99
tissue around the dorsla root ganglia form the __________, whichh will differentiate into what 2 things?
- somites
- differentiate into muscle and bones
100
differentiation of the neural tube creates a dorsal sensory region, the _____ _______; and a ventral, motor region the ________ ________
alar plate
basal plate
101
what differentiates into gray matter?
what is composed of axons/white matter?
- cells in the mantle differentiate into gray matter
- the marginal layer is composed of axons/white matter
102
103
Neural tube defects: anecephaly
serious brith defect in which a baby is born without parts of the brain and skull
| A = without
Cephalo = brain.head
Hydr(o) = water
Cele = tumor/swellin
104
Neural tube defects: hyranencephaly
serious brain defect in which the brain;s cerebral hemispheres are absent to a great degree abd the remaining cavity are filled with CSF
105
Neural tube defects encephalocele
smaller skull defect with partial protrusion of the brain typically in the frontal or occipital region
## Footnote
hydrocephalus is a frequent comorbidity
106
Spina bifida
a congential neural tube defect of the spine in which part of the spinal cord and its meninges are exposed through a gap in the backbone
107
Spina bifida occulta
incomplete vertebral arch; no lamina or spinous oricess; spinal cord, meninges, and CSF are contained in the spinal canal; skin covering the defect, and may be a dimple, a small patch of hair
108
Meningeicele
no lamina ir spinous process: spinal cord is still within the spinal canal, but there is no protursion of the meninges and cerebral spinal fluid outside of the spinal canal.
109
Myelomeningocele
protruding sac contains components of the spinal cord, meninges, and cerebral spinal fluid outside of the spinal canal.
110
What are the two malformations associated with hydrocephalus?
## Footnote
swollen ventirles (fluid in the brain)
- chiari type I malformation: herniation of inferior cerebellar vermis
- chiari type II malformation: caudal herniation
111
Disorders of forebrain development: holoprosencephaly
- malformation resulting in abnormal growth and seperation of the developing forebrain
3 types:
- alobar
- semi lobar
- lobar
risk factors:
- maternal DM
- fetal alcohol syndrome
- congenital infections
- trisomy 13
- genetic mutations
112
# Disorders of neuronal migration
What is agyria?
the brian is virtually devoid of surface convolutions expected for age
113
# Disorders of neuronal migration
What is pachygyria
Reduced numbers if gyri, and gyri present are abnirmaly broad
114
# Disorders of neuronal migration
What is polumicrogyria?
numerous abnormally convoluted gyri
