Test 3 Flashcards
1
Q
UMN
A
Motor neuron in CNS
2
Q
LMN
A
Motor neuron in PNS
3
Q
Are the motor pathways away from the brain ascending or descending?
A
Descending
4
Q
What is the corticosponal pathway?
A
Through pyramids, crosses to the other side of the body, consists of 2 neurons UMN and then the LMN which goes to the effector muscle
5
Q
What kind of pathway is involved in posture?
A
Ipsilateral polysnaptic pathway
6
Q
Describe the sensory pathways to the brain
A
Ascending and crosses to the other side of the pyramid
7
Q
cranial nerve 12. Arises from? Exits from? Function?
A
Hypoglossal Nerve
Arises from brain stem
Exits Hypoglossal canal
Mixed nerve. Motor to tongue. Sensory for muscle sense of tongue
8
Q
Cranial nerve 1 Arises from? Exits from? Function?
A
Arises from cerebrum
Exits though olfactory foramina
SMELL
9
Q
Cranial nerve II Arises from? Exits from? Function?
A
Arises from diencephalon
Exits optic foramen
Vision
10
Q
CN III Arises from? Exits from? Function?
A
Arises from brain stem
Exits through superior orbital fissure
Mixed nerve (m: intrinsic to extrinsic eye muscles, s: muscle sense)
11
Q
CN IV: Arises from? Exits from? Function?
A
Trochlear nerve
Arises from brain stem
Exits superior orbital fissure
Mixed nerve (m: ex eye muscle s: muscle sense)
12
Q
CN V: Arises from? Exits from? Function?
A
Trigeminal Nerve Arises from brain stem 1. Ophthalmic branch out SUF 2. Maxillary branch out rotundum 3. Mandibular branch out ovale
Mixed nerve (m: chewing s: muscle sense and parts of the face)
13
Q
CN VI: Arises from? Exits from? Function?
A
Arises from brain stem
Exits SUF
Mixed nerve (m: ex eye muscle s: muscle sense)
14
Q
CN VII: Arises from? Exits from? Function?
A
Facial nerve
Arises from brain stem
exits skull through Stylomastoid foramen of temporal bone
Mixed nerve (m: facial expression s: taste and muscle sense)
15
Q
CN VIII: Arises from? Exits from? Function?
A
Acoustic
Arises from brain stem
Exits through IAM
Function: sensory only
V: equilibrium
S: taste and muscle sense
16
Q
CN IX: Arises from? Exits from? Function?
A
Glossopharangeal nerve
Arises from brain stem
Exits through jugular foramen
Mixed nerve (m: swallowing s: taste and muscle sense)
17
Q
CN X: Arises from? Exits from? Function?
A
Vagus nerve
Arises from brain stem
Exits skull through jugular foramen
Mixed Nerve (m: parasympathetic nervous system s: muscle sense)
18
Q
CN XI: Arises from? Exits from? Function?
A
Accessory nerve
Arises from CN I arises from brain stem and the spinal nerve arises from cervical spinal cord
Exits skull through jugular foramen
Motor to sternocleidomastoid
Sensory muscle sense of same area
19
Q
Which cranial nerves are mixed?
A
All except I, II, and VIII
20
Q
Describe the location and function of the cerebellum. Name the furrow that divides the cerebellum from the cerebrum?
A
Location is interior and posterior brain and it is control of coordination and equilibrium. The transverse fissure separates it from cerebrum
21
Q
Contrast functions of the left vs right hemispheres of the brain?
A
Left Bain controls right hand, speech and analytical skills
Right brain controls artistic abilities, thinking in 3D and left hand
22
Q
Describe the location and function of the limbic system?
A
Cerebrum and diencephalon
Responsible for emotions related to survival such as finding sex pleasurable that relate to survival
23
Q
Describe the general function of the basal nuclei?
A
Smoothing out motor activity
24
Q
Name the 9 main functional areas of the cerebral cortex. Describe the basic functions of each area and their general location (i.e. lobe)?
A
1 Motor, 2 Premotor, and 3 motor speech are all in the frontal lobe
4 General sensory, 9 taste are in the parietal
5 Hearing and 6 Olfaction are in the temporal lobe
7 Vision is in the occipital lobe
8 Association areas are responsible for intelligence and thought are throughout all lobes
25
Name the surface layer of gray matter of the cerebrum. Name the gray matter just deep to this?
Cerebral cortex, basal nuclei which “fine tunes” motor activity
26
Name the furrow that divides the cerebrum into left and right hemispheres. How are these hemispheres internally connected?
Longitudinal fissure divides the hemispheres of the brain. They are internally connected by the corpus callosum.
27
Name the 3 fiber tracts in the white matter of the cerebrum. Describe their general functions?
Commissural fibers (primarily the corpus callosum) go from one hemisphere to the other
Association fiber interconnect with a lobe of the cerebrum
Projection fibers are the ascending sensory pathways and the descending motor pathways
28
Name the 4 lobes of the cerebrum?
Temporal, frontal, parietal, and occipital
29
Define gyrus, convolution, sulcus and fissure as they relate to the cerebrum?
A gyrus to a convolution is the bump or fold of the cerebrum. The sulcus is a dip between convolutions and a fissure is a big dip.
30
Define cerebral cortex?
gray matter (outer cerebrum) of cerebrum
31
Name the largest portion of the human brain.
cerebrum
32
Name the 2 main components of the diencephalon. Describe their locations and functions?
Thalamus is superior to mesencephalon and is the main sensory relay center. All sensory information passes thought here besides smell. Info gets passed to the cerebrum, but also stops unimportant sensory information
Hypothalamus is just below the thalamus. It is the center for homeostasis information; thirst, temp, hunger, and regulates and autonomic nervous system. Also responsible hormone related emotions.
33
Describe the function of all of the parts of the mesencephalon?
cerebral peduncles are important centers for descending motor pathways.
Superior colliculi are responsible for visual reflexes and inferior colliculi and responsible for auditory reflexes
34
Describe the function of the pons.
bridges the part of the brain (es cerebellum and medulla) and also helps regulate breathing
35
Describe the function of the reticular formations (Reticular Activating System).
controls consciousness and sleep
36
Describe the functions of the medulla oblongata.
Connects brain and spinal cord. Vital functions are controlled here such as breathing, blood pressure and hear functions, houses the reticular activating system which causes you to be awake when stimulated and coordinated other reflexes such as swallowing, vomiting, etc.
37
Explain why the right cerebrum controls left muscular movements of the body.
At the pyramids the pathways (both motor and sensory) cross to the other side of the body
38
Which cranial nerves originate from the brain stem?
III-XII
39
Name the 3 parts of the brain stem and describe their locations.
Medulla oblongata is most inferior
Pons is just above it
Mesencephalon is above the pons
40
Name the 4 main parts of the brain.
Cerebrum, cerebellum, brainstem, and diencephalon
41
Describe the function of CSF.
Cushion, nourishment, and transport of nutrients/waste
42
Explain the formation of CSF, and describe its circulation.
Formed from blood in the choroid plexus which line the ventricles— especially in the lateral ventricles. It circulates as described in number 3 and then in the subarachnoid space of brain & spinal cord
43
Describe how these ventricles interconnect.
The lateral and 3rd ventricle connect through the inter-ventricular foramen
The third and fourth ventricles connect through the cerebral aqueduct
44
Name and locate the brain ventricles. (What is a ventricle?)
Ventricles are cavities in the brain
The cerebrum has the lateral ventricles
Diencephalon has the 3rd ventricle
Brainstem has the 4th ventricle
45
Name the plexus of origin, and the general structures or areas innervated by the radial, ulnar, musculocutaneous, median, femoral, sciatic, and phrenic nerves?
Radial Nerve: brachial plexus Innervates pectoral limb extensors
Ulnar nerve: brachial plexus Innervates sitar medial flexors (flexor carpi ulnaris)
Musculocutaneous nerve: brachial plexus Innervates elbow flexors (biceps brachii)
Median nerve: brachial plexus Innervates distal lateral flexors (eg flexor carpi radialis)
Femoral nerve: lumbar plexus Innervates hip flexors and knee extensors (quadriceps)\
Sciatic nerve: sacral plexus Innervates knee flexors (hamstrings) as well as all distal to your knee
Phrenic nerve: cervical plexus Innervates your diaphragm and needed to breathe!
46
Name and locate the 4 main plexuses.
Cervicle (C1-4):
Brachial (C5-T1):
Lumbar (L1-4):
Sacral (about L4-S4
47
Define plexus:
network of successive spinal nerves
48
Describe a spinal nerve; include the roots, and which roots carry motor/sensory impulses?
Spinal nerves taking/giving messages via the spinal cord.
dorsal root sensory info carrying sensory info into the dorsal gray horn
Ventral root carrying motor info exiting the ventral gray horn
After the mixed spinal nerve leaves the vertebra, it branches into a dorsal ramus (branch) going toward your back and a ventral ramus going everywhere else in your body, including limbs and viscera. The rami are mixed.
49
Contrast monosynaptic, polysynaptic, ipsilateral, and contralateral reflexes. Describe the pathway for the patellar reflex, the withdrawal (flexor) reflex, and the crossed-extensor reflex.
One synapse in the spinal cord is monosynaptic means it is monosynaptic and would be very fast. The patellar reflex is monosynaptic and ipsilateral.
A polysynaptic reflex has more than one synapse in the spinal cord— this synapsing on interneuron or association neurons before synapsing on the motor neuron. Slower reflexes
If they stay ipsilateral (withdrawal reflex)
If they go contralateral (crossed extensor reflex)
50
Describe the pathway of a generalized reflex arc.
Stimulus, receptor, afferent sensory neuron, CNS, efferent motor neuron, and then to the effector
51
Define reflex, spinal reflex, somatic reflex, and autonomic reflex.
Reflex is a fast repetitive response to a stimulus. It is involuntary (ex not at the conscious level.) If it involved the spinal cord it is a spinal reflex. A somatic reflex terminals in skeletal muscles, the autonomic reflex terminates in smooth muscle, cardiac muscle and glands
52
Describe the function of the ascending and descending tracts.
Within the white columns are ascending tracts carrying sensory info toward the brain and the descending tracts carrying motor info away from the brain
53
Describe the parts of the gray matter of the spinal cord.
The dorsal gray horns receive sensory information
The ventral gray horns transmit motor information
Since it is gray, it would contain neuron cell bodies, and unmyelinaed neurons
54
Name the space and location where anesthetics are given.
Epidurals are given outside of the dura mater
| L2 or below would be a safe place to administer the anesthetic without hitting the spinal cord
55
Describe the location of the cerebrospinal fluid (CSF)
Subarachnoid space
56
Name the protective coverings of the CNS (general & specific).
```
General= meninges
Specific= dura mater, arachnoid, and pia mater
```
57
Describe the significance of the two spinal cord enlargements.
arms and legs nerves entering and exiting spinal cord
58
Describe the location of the spinal cord
vertebral foramen/canal
| Run from foramen magnum to ~L2
59
Describe the overall functions of the spinal cord.
Carry messages to and from the CNS
| spinal reflexes
60
Define spinal nerve and cauda equina.
Part of the peripheral nervous system taking messages to and from spinal cord. They are mixed, carrying both sensory and motor info.
The caudal-most spinal nerves pass caudally together, resembling a horse’s tail, before exiting the appropriate intervertebral foramen
61
Define effector and end-plate potential.
The stopping point for the neuron – such as a muscle or a gland. The depolarization in the effector is the end-plate potential.
62
Describe adaptation. Which sensation does not adapt?
Pain does not adapt. With an unchanging stimulus, receptors stop responding.
63
Define receptor and describe how a stimulus leads to a nerve impulse and how we can distinguish a weak from a strong stimulus.
The dendrite is the receiving end of the neuron. Its job is to take the stimulus and turn it into depolarization which is what the neuron understands. The more dendrites stimulated, the stronger the stimulus. Also, a strong stimulus will send a high frequency of impulses to the brain.
64
Describe temporal and spatial summation
Temporal summation is summation in time. If at a synapse you have one EPSP and another one rapidly follows and then another one... you will likely have enough depolarization to reach threshold
Spatial summation is summation in space. This would occur in a situation such as convergence where each presynaptic neuron releases a little bit of neurotransmitter going to the post synaptic neuron an all of the pre’s together will add their neurotransmitter together and it will likely be enough to reach threshold in the postsynaptic neuron and send the message along its way
65
Contrast convergence and divergence as it relates to neural integration:
one presynaptic neuron synapsing with several postsynaptic neurons is divergence; many presynaptic neurons synapsing with one postsynaptic neuron is convergence
66
Define neuromodulator and give an example.
This is a chemical that influences the neurotransmitter or the response to it. For example, endorphins block the pain neurotransmitters.
67
Define catecholamine
Neurotransmitters that are structurally similar include dopamine, epinephrine, and norepinephrine
68
Name the enzyme that breaks down acetylcholine.
Acetylcholinerase
69
Contrast excitatory postsynaptic potentials (EPSP) and inhibitory postsynaptic potentials (IPSP).
If the neurotransmitter causes depolarization in the postsynaptic neuron it is an EPSP
If it causes hyper-polarization (more negative) in the postsynaptic neuron it is an IPSP
These are graded changes (not all or none)
70
Describe the action of neurotransmitters. Give an example of a neurotransmitter.
Neurotransmitters are released at the synapse and diffuse across the synapse. There are receptors for the neurotransmitter at the post synaptic neuron bc their Na gates at this location are chemical (neurotransmitter) regulated rather than the voltage regulated gates on the rest of the neuron. Acetylcholine, norepinephrine, and dopamine are some examples.
71
Define synapse, presynaptic neuron, postsynaptic neuron, synaptic cleft, synaptic vesicle, and neurotransmitter.
Synapse is the junction between adjacent neurons involving the neuron entering the synapse called the presynaptic neuron and the one exiting is the post synaptic neuron
The physical space between them is the cleft
The vesicle is the bubble filled with neurotransmitter in the presynaptic neuron
The neurotransmitter is the chemical released that bridges the synapse
72
Explain why normal nerve impulses tend to be unidirectional.
Only because they always START at one end of the neuron and therefore can only go in one direction
73
Define the all-or-none principle of nerve impulse transmission.
Either an action potential reaches threshold or it doesn’t
74
Discuss the factors that determine the speed of impulse conduction.
Primarily, it is the presence of myelin. Fast with myelin, The more myelin, the faster.
Also, increased temp increases impulse conduction
75
Describe the events of a nerve impulse in myelinated and unmyelinated neurons.
Unmyelinated neurons— current flows all the way along the axon. A series of action potentials travel along the neuron at about 2mph.
Myelinated neurons— the myelin insulates against electrical current so that the action potentials can only occur at the node of Ranvier and therefore the current jumps from node to node (saltatory conduction) which is way faster 250+ mph
76
Explain how the sodium and potassium concentrations return to the levels of an unstimulated neuron, following an action potential.
sodium potassium pump— note that ATP is required
77
Which cells have action potentials? Describe the events of an action potential.
Depolarization to a threshold. A stimulus causes Na gates to open and Na to flood in. More and more sodium gates are opened (positive feedback cycle) until the inside of the cell is all positive. The sodium gates are only open for a brief period of time and the K gates are open for a long time. K leaves the cell due to diffusion and repelling of charge. This is the repolarization of action potential.
78
Define local potential.
Local potential is when localized depolarization where sodium’s can enter the cell due to an open sodium gate, but then the gate close and the potential is over (not a run away cycle)
79
Describe depolarization and repolarization.
Depolarization is when the cell becomes more negative on the outside
Repolarization is when the cell returns to resting membrane potential
80
Describe the factors that contribute to establishing the resting membrane potential.
Na/K pump helps keep outside more positive
K diffuses out due to diffusion
Selective permeability of Na (doesn’t let it in)
81
What is the approximate voltage of a neuron’s resting membrane potential?
-70mV, meaning that the inside of the cell is much more negative
82
Explain how the Na+/K+ pump contributes to the resting membrane potential.
The pump is not equal in charges, 3 Na out for every 2 K in
83
Describe a membrane potential.
A charge diff between inside and outside the cell
84
Define cation and anion.
```
Cation= +
Anion= -
```
85
Classify neurons according to structure.
Bipolar neuron: one axon and one dendrite
Multipolar neuron: numerous dendrites and one axon (the most common- eg motor neurons)
Unipolar: one extension that branches into the dendrite and the axon (found in sensory neurons)
86
Define nerve. Where are nerves located?
Groups of axons (only found in the PNS)
87
Define neuroglia and give an example of a neuroglial cell.
About half of nervous tissue is supportive cells called neuroglia. This includes Schwann cells (regenerating, myelin making cells in the PNS), oligodendrocytes (myelin making cells in the CNS), and astrocytes (help with the blood brain barrier)
88
Explain the nature of the blood-brain barrier.
The astrocytes are in between the blood and brain cells. Thus a poison would not go directly to the brain from the blood, but rather to the astrocyte
89
Describe how a peripheral nerve is regenerated if cut, and explain why an axon of the CNS cannot regenerate as well.
Schwann cells, only in PNS, can make a regeneration tube which is scaffolding for the cut ends of the axon to follow during regeneration
CNS cannot regenerate as well because there are no Schwann cells in the PNS
90
Distinguish between the structure of a myelinated and an unmyelinated axon, and describe how a myelin sheath is formed.
Myelin is a fatty substance wrapped in layers around the axon.
The myelinated is made by
Schwann cells in the PNS
oligodendrocytes in the CNS.
Myelinated neurons send nerve impulses much faster than unmyelinated.
91
Contrast white and gray matter.
White matter: myelinated neurons
| Gray matter: un-myelinated neurons
92
Define nuclei and ganglia as they relate to nerve cell body location.
Nuclei (a clump of cell bodies of neurons in the CNS)
occur in the gray matter of the brain
Ganglia (clumps of cell bodies in the PNS)
form the plexuses
93
Name the 3 main parts of a neuron and describe their functions:
axon (sending messages away from the cell body)
body (location of organelles)
dendrite (receiving end to receptor end, can be more than one dendrite)
94
Classify the organs of the nervous system into central and peripheral divisions. Include in your classification, the terms afferent, efferent, somatic, visceral, and autonomic nervous system (parasympathetic/sympathetic):
CNS is brain and spinal cord.
PNS is everything traveling away (efferent/motor) or toward the CNS (afferent/sensory)
If impulses are going toward your skeletal muscle that would make them somatic efferent
If impulses are going to smooth muscle, cardiac muscle or glands they are visceral efferent (ANS)
95
Identify the 3 basic functions of the nervous system in maintaining homeostasis:
sensory, integration, and motor
96
What are the two parts of the PNS?
Afferent: sense
Efferent: motor
97
What does somatic and visceral mean?
```
Somatic= surface of the body
Visceral= internal part of the body
```
98
What are the components of the autonomic (visceral) System?
Parasympathetic: rest and digest
| Sympathetic; fight or flight
99
The somatic efferent System controls?
Skeletal muscle
100
Groups of the cells bodies in the CNS
(nuclei)
101
Groups of the cells bodies in the PNS
(ganglia)
102
The receptive end of a neuron is known as the
dendrite
103
The conducting end of a neuron are known as
nerve fibers or axon
104
Nerve
Bundle of axons in PNS
105
Neuroglia (glial)
Nerve glue, supporting and protecting tissue
106
3 types of glial cells and their main role?
Schwann cells: make myelin in the PNS and allow for regeneration
Oligodenroctyes: myelin production in CNS
Astrocytes: maintenance of blood brain barrier
107
What is the range of the spinal cord?
foramen magnum to L2
108
Where is the epidural space located?
Dura mater
109
What does the central canal of the spinal cord gray matter contain?
Contains CSF
110
The gray matter of the dorsal pathway is?
Dorsal
111
The ventral horns are _______ pathways
Motor pathways
112
What are the 3 columns of white matter in the spinal cord and their main functions?
Anterior
Posterior
Lateral
