Neurobiology Test 1 Flashcards
1
Q
dorsal
A
posterior. usually represents the back
2
Q
ventral
A
anterior. in humans, its our stomach
3
Q
rostral
A
top. its our head in humans
4
Q
caudal
A
bottom. its our feet in humans
5
Q
sagital
A
cut face so it’s left and right
6
Q
coronal
A
cut head so it’s face and back of head
7
Q
horizontal
A
cuts so there is a top and bottom
8
Q
what are the planes in the brain stem?
A
transverse (slightly angular) and cross (completely horizontal)
9
Q
what are the limb movements?
A
flexion (arm up), extension (arm down), supination (twist arm out), pronation (twist arm in), abduction (bring leg out to the side), adduction (bring leg in)
10
Q
anatomic orientation
A
left to right
11
Q
clinical orientation
A
right to left
12
Q
contralateral
A
lateralization that is opposite to something
timulation of the left side of the body activate
the right side of the cortex & visa versa
• Motor commands from the left cerebral cortex
are sent to the right side of the body
13
Q
decussation
A
the spot where it switches from the right side to the left side and vice versa
14
Q
Breakdown of the Nervous System
A
CNS (Central nervous system) and PNS ( peripheral nervous system)
15
Q
Breakdown of the Central Nervous System
A
Somatic (voluntary) and autonomic (involuntary)
16
Q
Breakdown of Autonomic Nervous System
A
Sympathetic (fight or flight. Arise from thoracic & lumbar nerves of spinal cord) and Parasympathetic (anti fight or flight. Arise from brainstem & sacral (S2-S4) regions of spinal cord. Courses in sacral spinal nerves and certain cranial nerves in the brainstem)
17
Q
Cerebrum (cerebral hemispheres)
A
Serves higher mental functions (cognition, language, and memory); integrates sensorimotor functions and perceptual experiences
18
Q
thalamus
A
Channels sensorimotor information to cortex. Participates in cortex-mediated functions. Regulates crude awareness of sensation
19
Q
hypothalamus
A
Regulates body temperature, food intake, water balance, hormonal secretions, emotional behavior, and sexual responses. Controls the activities of autonomic nervous system.
20
Q
cerebellum
A
Participates in the coordination of skilled movements and regulation of equilibrium
21
Q
midbrain
A
Mediates auditory and visual reflexes. Regulates cortical arousal. Houses cranial nerve nuclei
22
Q
pons
A
Contains cranial nerve nuclei and sensory motor- regulating fibers
23
Q
medulla
A
Contains cranial nerve nuclei. Regulates respiration, phonation, heartbeat, and blood pressure
24
Q
spinal cord
A
links body with central nervous system & regulates reflexes
25
telencephalon
cerebral hemispheres; embryonic structure from which the cerebrum develops prenatally.
26
brainstem
medulla, pons, midbrain
27
hindbrain
Brainstem + cerebellum
28
diencephalon
thalamus, hypothalamus, epithalamus & subthalamus
29
forebrain
diencephalon + telencephalon
30
neocortex
6 layers of cells in the cerebral cortex
31
allocortex
3 layers of cells & include hippocampus, septal region, cingulate gyrus & parahippocampal gyrus.
32
basal ganglion
Regulates cognitive motor functions & muscle tone
| • Consist of 4 nuclear masses: caudate nucleus, putamen, claustrum & globus pallidus
33
damage basal ganglion
• Damage results in inappropriate behavioral & movement patterns because of disinhibition (e.g., Parkinson disease,
Huntington disease , Tourette syndrome, Wilson disease & Sydenham chorea)
• Basal ganglion lesions do not cause paralysis, but cause involuntary movements, such as tremor, chorea (jerky movements),
ticks & Ballism (violent flinging movements)
34
brainstem reticular formation
The reticular formation is a group of diffusely localized nuclei that are entangled in a network of fibers.
• Reticular neuronal circuits inhibit, facilitate, modify & regulate all cortical functions
• It also integrates all sensorimotor stimuli with internally generated thoughts, emotions & cognition.
• It also maintains the homeostatic state of the brain (e.g., hormones, etc.)
35
cerebellar peduncles
Cerebellum: coordinates & regulates smooth muscle/motor activities
Peduncles: allow information into and out of cerebellum
superior peduncle: info allowed out
inferior: info from spinal cord and also from inferior olivary (cortex)
middle peduncle: allows info from cortex
The peduncles are how the cortex/spinal cord can coordinate movement
Page 24 pictures
36
meninges
Membranes (n=3) that covers and protects the neurosis
duramater, arachnoid, and pia mater
page 25 pictures
37
Sensory aspect of autonomic nervous system
It receives constant sensations from visceral organs, monitors carbon dioxide in the blood & senses smooth muscle stretching (internal organs & blood
vessels)
38
motor aspect of autonomic nervous system
controls motor activity of smooth & cardiac muscles, such as lungs, kidney, gastrointestinal tract, eyes & heart
It also regulates the secretion of glands to produce: salivation, sweating, lacrimation (tears) as well as gastric, intestinal & pancreatic glands.
The motor component consist of the sympathetic & parasympathetic systems, which monitor, regulate & sustain optimum visceral functions essential for surviva
39
different kinds of ganglion
| (pictures on pg 26
Pre (myelinated/fast) vs post-ganglion (nonmylinated/slow)
Parasympathetic ganglion is closer to organ Sympathetic ganglia innervates many organs while parasympathetic ganglia innervates a single organ
40
Sympathetic spinal cord activation
T1-L3
41
Parasympathetic spinal cord activation
S2-S4
edinger-westphal nucleus
superior and inferior salivary nucleus
dorsal nucleus
42
pituitary (master) gland
Master endocrine system of the CNS.
• It maintains body homeostasis
• It controls various glands & tissues by secreting hormones & chemical messengers
• The anterior lobe is called
adenohypophysis & the posterior lobe is the neurohypophysis
• The hypothalamus can regulate the function of this gland by releasing hormones in the hypothalamic hypophyseal portal (blood) circulation
43
pituitary gland hormones
```
GH-growth hormones
TSH-thyroid-stimulating hormones
ACTH-adrenocorticotropic hormone
FSH-follicle stimulating hormone
LH-luteinizing hormone
MSH-melanocyte stimulating hormone
```
44
cerebrospinal fluid (CSF)
Serves to: supply nutrients to nervous tissues, removes waste & is a mechanical barrier to cushion the brain & spinal cord against trauma.
• A filtrate of blood but the blood brain barrier restricts entry of blood cells, large protein complexes & lipids, therefore CSF does not resemble blood (clear fluid)
• Choroid plexus & ependymal cells produce CSF & the arachnoid granulations absorb it into the venus to maintain balance
• CSF is found in the ventricles & subarachnoid space.
45
choroid plexus
invaginated in the ventricles, the pia-capillary network responsible for secreting the CSF.
46
ventricular (CSF cavity) system of the CNS
| picture on 30
lateral ventricles: cerebral hemispheres
inter ventricular foramen
third ventricle: diencephalon
cerebral aqueduct
fourth ventricle: pons and upper medulla
central canal: lower medulla and spinal cord
The shapes of the ventricular cavity & descending corticospinal (motor) fibers are two distinct anatomical landmarks that can be used to grossly determine where you are within the CNS
47
neuronal structure
has 3 general parts: dendrite, cell body & axon
48
dendrite
allows information to enter the cell (afferent/receptive) & travel to the cell body
• Have spines (red in fig) that increase the surface area for synaptic contacts
49
cell body or soma
allows for the entry of info (with or without the dendrite), the transmission of info & the integration & processing of info
• Composed of nucleoplasm & cytoplasm
• Nucleoplasm = DNA, chromatin, RNA (e.g., mRNA), nuclear bodies (e.g., nucleolus) & proteins
• Cytoplasm = RNA (rRNA), proteins, nucleotide pools & organelles: mitochondrioa, ribosomes, lysosomes, rough & smooth endoplasmic reticulum,
Golgi apparatus, etc.
50
axon
transmit information from the soma to other cells (efferent/transmissive)
• Axons originate at a cone shaped region called the axon hillock (initial segment)
• Axons are sometimes wrapped by another type of cell called an oligodendrocyte (CNS) or Schwann cell (PNS). This wrapping (lipids) is white and is called
myelin
• Myelin protects the axon & facilitates the fast transmission of electrical signals along the axon by preventing the escape of ions
(except at the nodes of Ranvier)
51
synapse
Allows for the local transfer of information (usually chemical) between cells (e.g., b/w axon & dendrite of 2 cells)
• Composed of presynaptic terminal (vesicles & boutons), synaptic cleft & postsynaptic cell area
• Nerve impulses/electrical activity triggers the release of vesicles in the synaptic cleft so that the postsynaptic cell
can retrieve the chemical signal
52
types of neurons
multi-polar, bi-polar, unipolar
There are many types of neurons with various morphological configurations
• There are many ways to classify types of neurons, e.g., morphology, function, chemical composition, location, etc.
• Below is an example based on morphology (number of dendrites & axons)
• Additional morphological typing is Golgi Type: Type-I has a long axon (inches to feet) while Type-II has short axons
53
neuron supporting cells (satellite cells)
Located everywhere neurons are located
• They support & protect nerve cells
• The most abundant types of cells in the nervous system (40-50 fold more than neurons)
• Examples in the CNS (Neuroglial Cells ) = astrocytes (transmission of substances across blood vessels), oligodendroglia
(forms myelin), microglia (garbage collector/killer) & ependymal (lines the ventricular cavity)
• Examples in the PNS = Schwann cell
54
communication: electrical
chemicals naturally want to move down their concentration gradient and voltage shifts occur across membranes from positive to negative, which are called oscillations
pg 39
55
storage and retrival process
Genes Structure
structure
• Neurons their circuits & •
```
function
Circuit dynamics their connectivity • Cognition, perception & motor
functions
```
56
storage and retrieval process cont.
genome to transipnome to proteome to metabolome to elementary functions and structures
57
the environment and plasticity
the environment can change the storage and function of the gene
58
basic principles of plasticity
The brain is composed of clusters of neurons that form neural circuits (black circles)
Neural circuits are connected to other spatially distinct neural circuits through fiber tracks (black lines) and other neural circuits
Large-scale functional systems may then develop from the combination of neural circuits
Synchronous activation of
spatially distinct neural circuits or functional systems drives sensory, motor and cognitive brain functions
Environmental stimulations are necessary for refining neural circuits and the larger functional systems
Redundancy is a key feature of the brain. One neural circuit may connect with another via multiple pathways.
59
connectivity and the environment
if there is a lesion or short circuit, the brain can fix itself autonomously or with therapy
60
nucleus
(pl. nuclei): mass of neuronal cell bodies in the central nervous system (CNS)
61
tracts
a bundle of parallel axons with a common point of origin & termination
62
Fasciculus
(pl. fasciculi, funiculi): several tracts
63
ganglion
(pl. ganglia): collection of neuronal cell bodies in the peripheral nervous system (PNS)
64
neuron
a single cell
65
nerve
a bundle of neurons
66
spinal cord
The spinal cord is located within the spinal canal but does not extend the entire length of the canal.
• The spinal cord extends from the foramen magnum to the lumbar (lower back) region of the spinal canal.
• The spinal cord is the major conduit through which sensory & motor info travels between brain & body
67
spinal cord segments and boundary lines
The spinal cord has 31 segments (8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal).
• There are no sharp boundaries between the segments within the cord.
68
spinal cord length
The spinal cord length is about 45 cm in men and 43 cm in women and its width ranges from 1.27 cm in cervical and lumbar regions to 64 mm in the thoracic region.
69
cervical segment
-located in neck -C1 to C8
70
thoracic segment
-located in chest -T1 to T12
71
Spinal Plexus
different spinal segments working together (5 Major ones). Cervical, Brachial, Lumbar, Sacral, and Coccygeal (last one not very relevant) plexuses.
72
Cervical Plexus
(C1-C5) supplies head, neck, and shoulders; contains phrenic nerve
73
Brachial Plexus
(C5-T1) supplies chest, shoulders, arms, and hands; contains radian, median, and ulnar nerves (complex neural network formed by lower cervical and upper thoracic ventral nerve roots which supplies motor and sensory innervation to upper limb and pectoral girdle located in neck, extending to axilla posterior to clavicle)
74
Lumbar Plexus
(L1-L4) supplies back, abdomen, and lower limbs; contains femoral nerve
75
Sacral Plexus
(L4-5, S1-4) supplies skin & muscles of pelvis, genitals, buttocks and lower limbs; contains sciatic nerve
76
Phrenic Nerve
mixed (sensory/motor) nerve (C3-C5) that innervates the diaphragm (cervical plexus)
77
Radian Nerve
provides motor and sensory innervation to arm & forearm and sensory innervation to hand (brachial plexus)
78
Median Nerve
one of five main nerves originating from brachial plexus and provides motor and sensory innervation to parts of forearm & hand
79
Ulnar Nerve
mixed nerve that supplies innervation to muscles in forearm & hand and provide sensation over the medial half of the 4th digit and entire 5th digit and ulnar portion of the posterior aspect of the hand (brachial plexus)
80
Femoral Nerve
located in pelvis & leg, helps muscles move the hip and straighten the leg, provides feeling (sensation) to front of thigh & part of lower leg (lumbar plexus)
81
Sciatic Nerve
largest single nerve in human body, runs from each side of lower spine through deep in the buttock into back of thigh and down to foot, vital role in connecting SC with leg and foot muscles (sacral plexus)
82
stimulus
produces Action potential
83
Electric Communication "code"
the amount of action potentials in a time tells neuron what to do (frequency or rate coding)
84
Chemical Communication
neurotransmitters for short range communication
| diffusible signaling molecules for long range communication
85
Chemical Communication "code"
volume of chemical tells neuron what to do (also the type of neurotransmitter)
86
Paracrine
From structure to brain
87
Endocrine
from structure to structure
88
Autocrine
cell regulates its own function by producing its own signaling molecule that affects its own receptors
89
Molecular Communication
after gene creates protein, it's modified in some way, the post translational modification affects the cell's receptors so they can communicate
This synaptic dialogue continues long after stimulus has gone and is then called rehearsal
90
Pruning
in the absence of stimulus over time, there's a loss of circuits
91
Expansion
provides for multiple neural representations of the stimulus
ensure survival of the original circuit
endogenous
92
Redundancy
key feature of the brain, one neural circuit my connect with another via multiple pathways, this allows for recovery of function (after damage)
93
Five Conceptual Function of the SC
1. Afferent (sensory)
2. Interneuron (decode/encode)
3. Efferent (motor)
(1-3: reflex)
4. input to the brain
5. executes commands from the brain
94
Reflex
Can go directly through SC, brain not necessary
| Ex: touch hot potato and drop it (reflex) or try to override reflex and hold onto it (now brain is involved)
95
Spinal Cord Ends
at approx the L1-L2 vertebral level
96
Conus Medullaris
most bulbous part of SC
97
Cauda Equina
horse-like collection of nerve roots at end of spinal cord
| formed from the lumbrosacral roots below termination of the SC
98
Filum Terminale
where tapering of SC occurs
99
Gray Matter
latitudinal aspects of SC
composed of neuronal cell bodies
responsible for either receiving or sending info via spinal roots and nerves
100
Spinal Roots
either afferent or efferent nerve bundles that enter or leave the SC
each SC segment (except C1) has dorsal and ventral roots and a pair of spinal nerves
101
Intervertebral foramina
where each dorsal and ventral root joins to form a spinal nerve
102
Accessory Nerve
(XI Cranial Nerve)
composed of 2 parts
Cranial part arises from nucleus ambiguus in brainstem
Spinal part arises from ventral horn between C1 and C5
103
Dorsal/Posterior Roots/Nerves
afferent (sensory) nerves carry info to SC
| occurs at Cervical, Thoracic, Lumbar, and Sacral regions
104
Fasciculus Cuneatus
afferent track of nerves that transmit info from above waist
105
Fasciculus Gracilis
afferent track of nerves that transmit info from below the waist
106
Denticulate ligament
part of pia mater, serves to protect and provide stability to SC
107
Dorsal Root Ganglion
the oval enlargement of the dorsal root (contains sensory neurons), is located outside the SC, proximal to its junction with ventral root
108
Sensory Ganglia neurons
pseudo-unipolar nerve cells
109
Dorsal Root Fiber types
```
largest afferent fibers (1a and 1b): heavily mylienated, conduct afferent limb of muscle stretch reflexes and carry info from muscle spindles
medium-sized fibers (A-beta): convey impulses from mechanoreceptors in skin and joints (e.g. touch)
small fibers (A-delta, thinly mylienated and C-type, unmylienated) convey noxious and thermal sensations (pain/temp)
```
110
Myotome
Descending and Motor
111
Corticospinal tract
body and limb movement (largest and most important descending tract) (extends all the way down to sacral)
112
Rubrospinal tract
flexor movement and upper limb (extends to lumbar)
113
Vestibulospinal tract
extensor and antigravity muscles (extends to lumbar)
114
Reticulospinal tract
muscle preparedness (extends to sacral)
115
tectospinal tract
reflex head turning (extends to cervical)
116
Dermatome
Ascending and Sensory
117
Gracile Fasciculus
touch, pressure, proprioception from BELOW the waist (extends up from sacral)
118
Cuneate Fasciculus
touch pressure, proprioception from ABOVE the waist (extends up from thoracic)
119
Spinothalamic tract
pain, temperature, and gross touch (extends up from sacral)
120
Spinoreticular tract
emotional reaction to and memory of pain (extends up from lumbar)
121
Spinocerebellar tract
proprioception and coordination of smooth movements (extends up from thoracic)
