Intro to Nervous System Flashcards
Anatomical Subdivisions
- CNS
- brain
- spinal cord
- PNS
- cranial nerves
- spinal nerves
- autonomic nerves
- ganglia
Meninges
&
Potential Spaces
Meninges
-
Dura mater
- tough outer layer
- own blood supply with meningeal arteries
- Arachnoid mater
- Pia mater
Spaces
- Epidural space ⇒ potential space between dura and skull
- Subdural space ⇒ potential space between dura and arachnoid
-
Subarachnoid ⇒ normally present
- contains CSF
- contains cerebral arteries and veins before they penetrate brain
- held against pia by arachnoid trabeculae
Intracranial Hemorrhages
Source of blood:
-
Meningeal artery
- epidural hematoma
-
Dural venous sinus
- subdural
- epidural
-
Vein at attachment to sinus
- subdural
-
Cerebral artery or vein
- subarachnoid
- intraparenchymal
- intraventricular
Venous Sinuses
- Contained within dura mater
- Drains the brain
- CSF ⇒ arachnoid villi ⇒ venous subarachnoid space ⇒ venous sinus
-
Major venous sinuses to know:
- superior sagittal sinus
- inferior sagittal sinus
- transverse sinus
- straight sinus
- sigmoid sinus
- Drains into the internal jugular vein
Dural Septa
- Folds of dura mater
- Firmly attached to cranium
- Increased intracranial pressure can cause brain herniation into other dural reflections
Major dural partitions to know:
Falx cerebri
Tentorium cerebelli
Falx cerebelli
Diaphragma sellae
Subdivisions of the CNS
Limbic System
-
Includes:
- limbic lobe
- cingulate gyrus
- parahippocampal gyrus
- hippocampal formation
- amygdala
- several nuclei of thalamus and hypothalamus
- limbic lobe
-
Functions:
- emotions
- memory
- appetitive drives
- autonomic and neuroendocrine control
Cortical Functions
-
Prefrontal cortex
- planning, judgement, decision making, working memory
- lesions cause defects as above and personality change
-
Premotor and supplementary motor
- rostral to primary cortex
- lesion ⇒ motor deficits (apraxia)
-
Primary motor cortex
- within precentral gyrus
- Unilateral lesion ⇒ contralateral motor deficits
-
Primary somatosensory cortex
- within postcentral gyrus
- unilateral lesion ⇒ contralateral sensory deficits
-
Posterior partietal cortex
- spatial orientation and sensory integration
- right sided non-dominant lesion ⇒ left hemi-neglect
-
Visual cortex
- within occipital lobe
- unilateral lesion ⇒ contralateral visual field deficit
-
Temporal lobe
- integrates complex auditory and visual information
- lesion ⇒ complex deficits (e.g. object/face recognition)
-
Auditory cortex
- within transverse gyri of superior temporal gyrus
-
Broca’s area
- motor speech
- lesion ⇒ motor aphasia
-
Wernicke’s area
- language comprehension of language
- lesion ⇒ sensory aphasia
Somatotopy
The somatotopic organization of the primary somatosensory and motor cortices.
Describes the neurological tracts associated with movement and sensation.
C-shaped structures
CSF Flow
CSF produced by choroid plexus in ventricles
⇒ 2 lateral ventricles
⇒ 2 interventricular foramen (of Monro)
⇒ 3rd ventricle
⇒ cerebral aqueduct (of Sylvius)
⇒ 4th ventricle
⇒ median aperature (foramen of Magendie) & lateral apertures (foramina of Luschka)
⇒ subarachnoid space
⇒ upward around brain and downward around spinal cord
⇒ arachnoid granulations (or villi)
⇒ superior sagittal sinus
⇒ venous system
Hydrocephalus
- Distension of the ventricles caused by occlusion or obstruction of CSF flow.
- CSF blockage will result in damage of adjacent structures due to pressure.
- Symptoms will suggest the location.
Cerebral Aquaduct Stenosis
Brain and Spinal Cord
Vasculature
-
Internal carotid arteries ⇒ anterior circulation
- middle cerebral artery
- anterior cerebral artery
- pericallosal
- callosomarginal
- anterior communicating
- anterior choroidal artery
- posterior communicating artery
- opthalmic artery
-
Vertebral arteries ⇒ posterior circulation
- basilar artery
- anterior inferior cerebellar artery
- superior cerebellar artery
- posterior cerebral artery
- posterior inferior cerebellar artery
- posterior spinal artery
- anterior spinal artery
- basilar artery
Brain
Blood Supply
-
Anterior cerebral artery (ACA)
- Supplies medial surface of parietal and frontal cortex
- Including leg region of primary motor cortex and primary somatosensory cortex
- Supplies medial surface of parietal and frontal cortex
-
Posterior cerebral artery (PCA)
- Supplies medial and inferior surface of occipital lobe and temporal lobe
- Including visual cortex and hippocampus
-
Middle Cerebral Artery (MCA)
- Enters lateral sulcus and branches into superior and inferior division branches
- Supplies lateral surface of the frontal, parietal, and temporal cortices
- Trunk, arm, and face region of primary motor cortex and primary somatosensory cortex
Sympathetic vs Parasympathetic
- Sympathetic
- cholinergic preganglionic neurons
- located in intermediolateral nucleus of T1-L2
- postganglionic neurons noradrenergic
- except Ach sweat glands
- cholinergic preganglionic neurons
- Parasympathetic
- cholinergic preganglionic and postganglionic neurons
- preganglionic neurons in spinal cored at S2-S4 and brain stem
T1 vs T2
Prefrontal Cortex
Functions
- Foresight
- Personality
- Insight
- Judgement
- Working Memory
Primary Motor Cortex
Located within the precentral gyrus.
Involved in the control of voluntary movements.
Premotor & Supplementary Motor
Areas
Involved in preparation and initiation of voluntary movements.
Broca’s Area
In the dominant side is involved in production of written and spoken language.
Primary Somatosensory Cortex
Located within the postcentral gyrus.
Processes somatosensory information.
Posterior Parietal
Association Cortex
Located within superior parietal lobule.
Involved with spatial orientation and complex sensory integration.
Wernicke’s Area
Inferior parietal lobule and caudal portions of temporal lobe.
In dominant lobe is involved in comprehension of language.
Primary Auditory Cortex
Located within the superior temporal gyrus.
Temporal Lobe
- Medial surface contains:
- uncus
- parahippocampal gyrus
- amygdala
- hippocampus
- Major functions:
- memory
- emotion
- color perception
- face and object recognition
Occipital Lobe
- Cuneus and lingual gyrus
- Seperated by calcarine sulcus
- Major funciton:
- processing of visual information
Amygdala
Lies beneath the uncus within temporal lobe.
Involved in emotions.
Hippocampus
Lies beneath the amgydala.
Involved in memory formation.
