central nervous system Flashcards
1
Q
Nervous System Subdivision
A
- Nervous System: collects, integrates and respond to internal and external information
- CNS: incoming sensory information and outgoing of motor information, and higher cognitive processes
- brain: inside the skull
- cerebral hemispheres, diencephalon cerebellum, brainstem
- spinal cord: inside vertebral canal
- 2/3 of canal, 43-45 cm
- start at medulla oblongata at level of foramen magnum
- ends at Li-ii (Liii for infants)
- brain: inside the skull
- PNS: communication lines with CNS and body, has sensory and motor divisions
- cranial nerves (12), spinal nerves (31), peripheral ganglia, nerve plexi
2
Q
PNS Subdivisions
A
- sensory / afferent division
- general, somatic senses: pain
- special senses: vision in eyes
- visceral senses: hunger from stomach
- motor / efferent division
- somatic nerves: skeletal muscles
- visceral motor / autonomic
- sympathetic: during activity (heart), either smooth muscle / cardiac muscle / glands
- parasympathetic: conserves energy (bladder), either smooth muscle / cardiac muscle / glands
- enteric plexus: GI tract
3
Q
Neural Tube
A
- Prosencephalon Mesencephalon, Rhombencephalon
- Telencephalon, Diencephalon, Mesencephalon, Metencephalon, Myelencephalon
- Cerebrum - convoluted (Lateral Ventricles)
- Thalamus, Hypothalamus, Epithalamus (Third Ventricles)
- Midbrain (Aqueduct of Midbrain)
- Pons+Cerebellum (Upper part of 4th)
- Medulla (Lower part of 4th)
4
Q
Nervous System Keywords
A
- nucleus: mass of cell bodies in CNS
- ganglion: mass of cell bodies in PNS
- tract/fasciculi: collection of processes in CNS
- cortex / grey matter: cell bodies, unmyelinated nerves, neuroglia
- white matter: myelinated nerves
5
Q
Spinal Cord Features (external)
A
- start: medulla oblongata at foramen level
- terminal end is tapered: conus medullaris
- end: Li-Lii intervertebrate disk
- 2 enlargements: needs more neurons in this area
- cervical e.: innervates upper limb
- lumbosacral e.: innervates lower limb
- 2 longitudinal grooves:
- ventral anterior median fissure:
- ventral rootlets emerge on either side
- joins to form ventral roots
- dorsal posterior median fissure:
- dorsal rootlets emerge on either side
- joins to form dorsal roots
- each root is associated with dorsal root ganglion
- ventral anterior median fissure:
6
Q
Spinal Cord Features (internal)
A
- Grey and White Matter
- grey: on the inside, H shaped
- white: outside surrounding it
- Horns: dorsal, lateral, ventral (grey)
- dorsal (sensory neurons) > DRG (in PNS)
- ventral (motor neurons)
- Columns: dorsal, lateral, ventral (white)
7
Q
Spinal Cord Segment
A
- section that gives attachment to spinal nerves
- spinal nerves: dorsal + ventral roots
- will branch off into roots and rami
- 31 segments (8 + 12 + 7 + 5 + 1)
- segments after spinal cord ends:
- parasympathetic nerves of lateral horn (Sii-Siv)
8
Q
Spinal Cord Tracts
A
- Sensory: starts in spinal cord (ascending)
- spinocerebellar tract
- spinothalamic tract
- Motor: ends in spinal cord (descending)
- corticospinal tract
- rubrospinal tract
9
Q
Sensory Tracts
A
- Number of Neurons: 3 except dorsal cerebellotract
- Location of Neurons: DRG, brainstem/spinal cord, thalamus
- Crossing at the midline: except cerebellar tracts)
-
Dorsal Spinocerebellar Tract: unconscious information to cerebellum, unconscious proprioception of lower limbs
- only 2 neurons: DRG and dorsal horn
- DRG > medulla oblongata > inferior cerebellar peduncle > ipsilateral cerebral column
-
Dorsal Column Tract: conscious proprioception and discriminative touch
- cp: from joints and muscles (except TMJ)
- dt: entire body except head
- DRG > Gracile and Cuneate Nuclei > crosses at midline > Medial Leminscus > thalamus
- test: close your eyes and see if you lose balance
-
Lateral and Anterior Spinothalamic Tract: pain, temperature and crude touch (everywhere except head)
- lateral: pain and temperature
- anterior: crude touch
- DRG > medulla > cross at medulla > thalamus
10
Q
Motor Tracts
A
- Location of UMNs for Pyramidal and Extrapyramidal: motor cortex of cerebral hemisphere v brainstem
- Location for LMNs: spinal cord for both (anterior horn)
-
Lateral and Anterior Corticospinal Tract: voluntary movement
- cerebral hemisphere > midbrain > pons > medulla > divide into 2 at medulla > spinal cord
- anterior corticospinal: 10-15% stay on anterior side
- lateral corticospinal: 85-90% crosses to lateral side
- cerebral hemisphere > midbrain > pons > medulla > divide into 2 at medulla > spinal cord
-
Rubrospinal tract: autonomic movement
- red nucleus > cross at midbrain level > synapse with motor neuron at ventral horn
11
Q
Brainstem
A
- Midbrain + Pons + Medulla Oblongata
- 4th Cerebral Ventricle
- Passageway of Tracts
- CN Nuclei III - XI
- Autonomic Behaviours
12
Q
Medulla Oblongata
A
- Pontomedullary Sulcus: border between medulla and pons
- Emerge: CN IX, X, XI, XII
- 2 elevations: pyramid and olive
- pyramid: caused by pyramidal tract / corticospinal tract
- olive: inferior olivary nucleus
- CN Nuclei: V, part of VIII, IX, X, XI, XII
- Grey White Matter:
- superior: white with grey embedded
- inferior: same as spinal cord (grey middle)
- 4th ventricle
- inferior olivary nucleus
- corticospinal tract, gracilis and cuneatus nucleus, medial leminscus
13
Q
Pons
A
- bridge for R and L Cerebellum
- emerge: CN VI, VII, VIII (pontomedullary sulcus), CN V
- basilar sulcus: has basilar artery
- 4th Ventricle: diamond shaped
- Cerebellar Peduncles
- Grey White Matter: white with grey embedded
- CN nuclei: CN V, VI, VII, VIII
- 4th ventricle
- medial leminscus
- corticospinal tract
-
Pontine Nuclei: relay center between cerebellum and cerebral hemisphere
- cerebral: gives orders, works on opposite side
- cerebellum: monitors, works on same side
14
Q
Midbrain
A
- Crus Cerebri of Cerebellar Peduncles
- Emerge: CN III, IV
- III: between peduncles
- IV: emerge from posterior!!
- Superior and Inferior Colliculi (4 bones, 2 per side)
- s: for visual reflexes
- i: for hearing reflexes
- Cerebral Aqueduct: connects 3rd and 4th ventricle
- CN III, IV, IV
- Grey White Matter: white with grey embedded
- Substantia Nigra
- Red Nucleus
- Crus Cerebri of Cerebral Peduncle (contain motor tracts)
15
Q
Cerebellum
A
- R and L hemispheres
- vermis: worm-like structure that connects R and L
- anterior lobe, posterior lobe, flocculondar
- primary fissure: between anterior and posterior
- Cerebellar Cortex: on the periphery
- formed by grey matter
- folded into leaf-like ridges: folia
- Grey White Matter: grey outside, white inside
- Cerebellar Peduncles
- superior: attach to midbrain
- middle: attach to pons
- inferior: attach to medulla
