Nueroanatomy Flashcards
1
Q
Central Nervous System (CNS)
A
Consists of the brain and the spinal cord. Integrating and command center of the nervous system: receives incoming sensory signals, interprets the signals, and dictates motor responses.
2
Q
Peripheral Nervous System (PNS)
A
Part of nervous system outside of CNS:
- Cranial nerves
- Spinal nerves
- Ganglia
3
Q
Ganglia
A
PNS
collection of cell bodies
4
Q
Sensory input
A
Afferent
Receive signals and gather information
5
Q
Integration
A
Integrate incoming signals (to determine whether or not the information should be passed along)
6
Q
Motor output
A
Efferent
Communicate signals to target cells (other neurons or muscles or glands)
7
Q
Dendrite
A
Receiving and processing end of neuron
8
Q
Cell body
A
Synthesizes information and proteins. Decides whether or not to send information down the line.
9
Q
Axon
A
Sending end of neuron.
Arises from the cell body at a specialized area called the axon hillock. Axons are covered with myelin, which helps them convey the nerve impulse rapidly.
10
Q
Somatic sensory
A
General: touch, pain, pressure, vibration, from skin, body wall and limbs.
Special: hearing, equilibrium, vision
11
Q
Visceral sensory
A
General: stretch, pain, temperature, chemical changes, nausea, hunger.
Special: taste and smell
12
Q
Somatic motor
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Motor innervation to skeletal muscles
13
Q
Visceral motor
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Motor innervation to smooth muscle, cardiac muscle and glands
14
Q
Multipolar neuron
A
many processes extend from the cell body; all are dendrites except for a single axon
15
Q
Bipolar neuron
A
two processes extend from the cell body: one is a fused dendrite; the other is an axon
16
Q
Unipolar (psuedounipolar)
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one process extends from the cell body and forms central and peripheral processes, which together comprise an axon.
17
Q
Where are bipolar neurons found?
A
rare, sensory neurons found in some special sensory organs (olfactory, eye, ear). Visual input from eye to brain.
18
Q
Where are multipolar neurons found?
A
most abundant in body, major neuron type in the CNS. Most are interneurons that conduct impulses within the CNS, some are motor that conduct impulses from CNS to effector ( muscle/gland).
19
Q
Where are unipolar (psuedounipolar) neurons found?
A
mainly in the PNS. Common only in the dorsal root ganglia of the spinal cord and sensory ganglia of cranial nerves.
20
Q
What is it called when one neuron connects up to another neuron?
A
a chemical event
21
Q
What is a reflex arc?
A
simple chains of neurons that cause our simplest, reflexive behaviors and reflect the basic structural plan of the nervous system.
22
Q
What is a neuron?
A
a nerve cell
23
Q
What is a nerve fiber?
A
a long axon
24
Q
What is a nerve?
A
a collection of axons in the PNS
25
What is a monosynaptic reflex?
one reflex. example: knee jerk
26
What is a polysynaptic reflex?
more common than monosynaptic, one or more interneurons are part of the reflex pathway between sensory and motor. Example: pricking a finger with a tack.
27
What is a sensory neuron?
afferent neuron, transmit impulses toward the CNS from sensory receptors in the PNS.
28
What is a motor neuron?
efferent neuron, make up the motor division of the PNS. carry impulses away from the CNS to effector organs (muscles and glands).
29
What is an interneuron?
lie between sensory and motor neurons. confined entirely to CNS. make up 99.98% of neurons in the body.
30
What is the function of glial cells?
Aka neuroglial. Provide support in the CNS and PNS (hold the brain together), insulate the neurons and keep electrical activities of adjacent neurons from interfering with each other.
31
What is an astrocyte cell?
(star cell) most abundant glial cell. Provides physical support (clasp and hold parts of neurons, wrap capillaries and hold them). can also signal increased blood flow through capillaries in active regions of the brain.
32
What is a microglial cell?
Immune defense
| Tiny cell; scavenger of the brain: migrate to and then engulf invading microorganisms and injured or dead neurons.
33
What is a oligodendrocyte cell?
produces myelin sheath
"few branch cells": line up in small groups and wrap their cell processes around thicker axons in the CNS, producing insulating coverings called myelin sheath.
34
What is a ranvier?
myelin sheath gap on a myelinated axon.
35
What is an ependymal cell?
"wrapping garment": bear cilia that helps circulate the fluid. Form a simple epithelium that lines the central cavity of the spinal cord and brain.
36
What are the support cells of the CNS?
1) Astrocyte
2) Microglial
3) Ependymal
4) Oligodendrocyte
37
What is a satellite cell?
surround neuron cell bodies within ganglia.
| resemblance to moons or satellites around a planet.
38
What is a schwann cell?
surround all axons in the PNS and form myelin sheaths around many of these axons. Monogamous.
39
What are myelin sheaths?
produced by oligodendrocytes in the CNS and Schwann cells in the PNS.
40
What is a peripheral nerve?
cable-like collection of axons
41
What is the endonerium?
myelinated axons covered by a thin layer of CT
42
What is a perinerium?
groups of axons, fascicles covered by CT
43
What is epinerium?
tough fibrous sheath covering the whole nerve.
44
What are the 4 regions of the brain?
1) cerebrum
2) diencephalon
3) brainstem
4) cerebellum
45
What is the cerebrum and its function?
- 2 hemispheres that account for 83% brain mass
- highest level of analysis of sensory input
- highest level of somatic motor control (i.e. plan responses)
- speech, articulation of thought, memory
- association of memory, emotion, reasoning, motivation, personality, judgement, intelligence, etc.
46
What is sulci?
grooves of the brain
47
What is gyri?
twisted ridges of the brain
48
What are the cerebral hemispheres?
1) frontal lobe
2) parietal lobe
3) occipital lobe
4) temporal lobe
49
What is the central sulcus?
Separates the frontal lobe from the parietal lobe
50
What is the precentral gyrus?
Primary motor function, lies anterior to the central sulcus.
51
What is the postcentral gyrus?
posterior to central sulcus, contains primary somatosensory cortex.
52
What is the fornix?
connects brain and limbic system - has to do w/ emotions.
53
What is the corpus callosum?
big band of white matter, tells left brain what right brain is doing and vice versa.
54
Anterior horn of lateral ventricle
remnant empty space filled with fluid
55
What is the diencephalon?
```
Forms the central core of the forebrain and is surrounded by cerebral hemispheres.
develops 3 main divisions:
- thalamus
- hypothalamus
- epithalamus
```
56
What is the thalamus?
makes up 80% of the diencephalon and forms the walls of the 3rd ventricle. contains about a dozen major nuclei.
- relays information to the cerebral cortex and processes the information as it passes through.
57
What is the hypothalamus?
inferior portion of diencephalon (below thalamus). forms inferolateral walls of 3rd ventricle. contains about a dozen brain nuclei of gray matter.
- main visceral control center of the body. Functions include:
control of automatic nervous system, regulation of body temp, regulation of hunger and thirst, regulation of sleep-wake cycles, control of endocrine system, control of emotional responses, control of motivational behavior, formation of memory.
58
What is the epithalamus?
third most dorsal part of the diencephalon, forms part of the roof of the 3rd ventricle. consists of one tiny group of brain nuclei and a small unpaired knob called the pineal gland.
59
What is the pineal gland?
Pineal gland secretes the hormone melatonin.
60
What is the septum pellucidum?
little curtain that helps to separate the ventricle on one side to the other.
61
What is the brain stem?
most caudal of the 4 parts of the brain. Has 3 regions:
1) medulla oblongata
2) pons
3) midbrain
62
What is the midbrain?
lies between the diencephalon and the pons. central cavity of the midbrain is the cerebral aqueduct.
63
What is the midbrain?
lies between the diencephalon and the pons, central part of the brain stem. central cavity of the midbrain is the cerebral aqueduct that divides the midbrain into the tectum and cerebral peduncles.
64
What are cerebri of cerebral peduncles?
ventral surface of brain, form vertical pillars that appear to hold up the brain. Big band of axons running up and down from the cortex into the rest of the brain stem.
65
What is corpora quadrigemina?
make up the tectum. Auditory and visual reflexes are integrated by the brain nuclei here. The nuclei form bumps that are the superior and inferior colliculi.
66
What are superior colliculi?
Act in visual reflexes: when eyes track and follow moving objects.
67
What are inferior colliculi?
Act in visual reflexes: when you are startled by a sound, you reflexively turn toward the sound because of inferior colliculi.
68
What is the cerebral aqueduct?
little canal part of the midbrain, that connects 3rd ventricle to the 4th ventricle
69
What is the Pons?
"bridge": second region of brain stem, bulge wedges between the midbrain and the medulla oblongata. Forms a bridge between brain stem and cerebellum.
70
What is the medulla oblongata?
Continuous with the spinal cord at the level of foramen magnum. Both sensory and motor going through. Lots of nuclei having to do with visceral activity. Balance and equilibrium, nausea
71
Lateral ventricles
lie in the cerebral hemispheres. Horseshoe shape. Anteriorly, the two lateral ventricles lie close together, separated by a thin membrane, septum pellucidum.
72
Third ventricle
lies in the diencephalon. Anteriorly, it connects to each lateral ventricle through an interventricular foramen.
73
Fourth ventricle
lies in the brain stem, dorsal to the pons and the superior half of the medulla oblangata. Connects to the central canal of the inferior medulla and spinal cord.
74
Olive
Sensory nucleus that looks like a kalamata olive in the medulla oblongata.
75
Pyramid
longitudinal ridges formed by pyramidal tracts, carrying voluntary motor output to the spinal cord.
76
What is the decussation of pyramids?
pyramid fibers cross over to the opposite side of the brain. The result of the crossover is that each cerebral hemisphere controls the voluntary movements of the opposite side of the body (i.e. when you lift your left hand to wipe the right side of your face).
77
Fasiculatus gracilis and cuneatus
relay nuclei. Ascending fibers carrying general sensation from the discriminative senses (touch, pressure) from the skin and proprioceptors synapse these nuclei along their pathway to the cerebrum.
78
What is the cerebellum?
means little cerebrum. 2nd of the brain's major parts. Functions:
1) coordinate somatic motor activity - makes real time adjustments'
2) Regulate muscle tone
3) Maintain equilibrium
Fiber tracts connect cerebellum with cerebral hemispheres and spinal cord
79
What are the ventricles of the brain?
As the brain develops, the hollowness of the brain becomes the ventricles.
- derived from central canal
- lined with ependymal cells
- filled with cerebrospinal fluid
80
What are meninges?
```
connective tissue outside the brain, between brain and skull that cover and protect the CNS, enclose and protect blood vessels, contain cerebrospinal fluid.
3 parts:
1) Pia Mater=gentle mother
2) Arachnoid mater=spidery mother
3) Dura mater=hard mother
```
81
Pia mater
Highly vascular CT membrane
Helps form choroid plexus
Adheres to surface of the brain
Vascular supply of brain within Pia
82
Arachnoid
Deep to dura mater. Web-like. 2 parts: subdural space that is filled with a film of fluid and subarachnoid that has web-like threads that hold the arachnoid mater to underlying pia mater..
Surround brain loosely
83
Dura
single layer in vertebral canal. double layer in cranium:
1) periosteal later=periosteum of skull
2) meningeal layer= inner layer, mostly follows contours of skull
84
Cerebrospinal fluid (CSF)
fluid that fills the subarachnoid space and the central hollow cavities of the brain and spinal cord. Protects and nourishes the neural tissue. Produced by choroid plexus.
85
Inner meningeal layer
A few folds dip deep into the cranium:
1) Falx cerebri
2) Tentorium cerebelli
3) Falx cerebelli
86
What is the function of falx cerebri?
helps keep cerebral hemisphere on one side from sloshing over to the other side
87
What is the function of tentorium cerebelli?
tent of the cerebelum
88
Falx cerebelli
curved knife. runs along vermis in cerebellum.
89
Arachnoid villi
bulges of arachnoid mater into venous sinuses
90
Venous sinuses
travel between two layers of dura
lined with endothelium
continuous with blood vessels
drain toward jugular foramen and internal jugular vein
91
What are the venous sinuses?
1) superior sagittal sinuses
2) inferior sagittal sinus
3) straight sinus
4) 2 transverse sinuses
5) 2 sigmoid sinuses
92
What is the CSF to blood process?
1) CSF is produced by the choroid plexus of each ventricle.
2) CSF flows through the ventricles and into subarachnoid space via median and lateral apertures. Some CSF flows through central canal of spinal cords.
3) CSF flows through the subarachnoid space
4) CSF is absorbed into the dural venous sinuses via arachnoid granulations.
5) CSF flows through the villi into the sinus system, all the way down to the jugular vein.
93
What are the components of a reflex arc?
1) receptor
2) sensory neuron
3) integration center
4) motor neuron
5) effector
94
what are the 3 elements of a synapse?
1) axon terminal
2) synaptic cleft
3) dendrite
95
afferent
- somatic and visceral sensory nerve fibers
| - signals are picked up by sensory receptors and carried to the CNS
96
efferent
- motor nerve fibers
| - signals are carried away from the CNS by nerve fibers of the PNS to innervate muscles and glands.
97
what is a synapse?
site where neurons communicate
98
What are the spinal nerves?
```
Cervical nerves: C1-C8 (at the top of T1)
Thoracic nerves: T1-T12
Lumbar nerves: L1-L5
Sacral nerves: S1-S5
Coccygeal nerve: C0
```
99
What is the role of the precentral gyrus?
Primary motor cortex
100
What is the role of the post central gyrus?
Primary somato-sensory cortex
101
What is the cervical plexus?
C1-C5
- innervates skin of neck, shoulder and clavicular regions
- infrahyoid muscles, scalenes, levator scapulae
- Phrenic nerve
102
What does the phrenic nerve innervate?
Innervates diaphragm
| C3, C4, C5
103
What muscles does the musculocutaenous nerve innervate?
- Corachobrachialis
- Biceps brachii
- Brachialis
104
What muscles does the median nerve innervate?
- flexor pollicis longus
- pronator quadratus
- pronator teres
- flexor carpi radialis
- palmaris longus
- flexor digitorum superficialis
105
What muscles does the ulnar nerve innervate?
- flexor carpi ulnaris
- flexor digitorum profundus
- adductor policis
106
What muscles does the radial nerve innervate?
- triceps brachii
- brachioradialis
- supinator
- extensor digitorum
- extensor carpi ulnaris
107
What muscles does the axillary nerve innervate?
- Teres minor
| - deltoid
108
What is the lumbar plexus?
L1-L4
109
What does the femoral nerve innervate?
anterior thigh muscles; iliacus, rectus femoris, vastus medialis, sartorus
110
What does the obturator nerve innervate?
medial thigh muscles; gracilis, adductor magnus, adductor brevis, longus, etc.
111
What is the sciatic nerve?
contains both tibial and common fibular nerves
112
What does the tibial nerve innervate?
posterior thigh, leg, foot muscles, biceps femoris, semitendinosus, gastrocnemius
113
What does the common fibular nerve innervate?
biceps femoris, tibialis anterior
114
pudendal nerve
skin and muscles of perineum, genitalia, etc.
115
Gluteal nerves
Gluteal muscles, gluteus medius, minimis and tensor fascia latae
