2.6: CNS and Neuroanatomy Flashcards
CNS is divided into
Brain - cerebrum, cerebellum, brainstem
Spinal chord
PNS is composed of
Nerves (cranial, spinal and peripheral)
Ganglia -cell bodies outside of CNS
PNS can be split into
Somatic - what you can feel
Autonomic
The brain is composed of (in foetal development)
Forebrain
Midbrain
Hindbrain
The forebrain is divided into the
Cerebral hemisphere
Diencephalon
The diencephalon is divided into the (foetal development)
Thalamus
Hypothalamus
The hindbrain is divided into
(foetal development)
Pons
Medulla
Cerebellum
The brainstem is composed of (adult brain)
Pons
Medulla
Midbrain
Cerebrum / cerebral cortex
outer layer of brain - consists of grey matter- 70% hidden in sulci
4 lobes
Grey matter
Unmyelinated cell bodies of neurons and 10x glial cells
Inner layers of the brain consist of
white matter
White matter
myelinated neuronal axons which form tracts
tracts help deliver information to and from cerebral cortex
lies in the anterior cranial fossa
frontal lobe of cerebral hemisphere
lies in the middle cranial fossa
temporal lobe of cerebral hemisphere
lies in the posterior cranial fossa
cerebellum
lies directly above the body of the sphenoid bone
hypothalamus
passes through the foramen magnum
medulla
Frontal lobe is responsible for
Motor function
language
cognitive function (planning, attention and memory)
Parietal lobe is responsible for
Sensation (touch, pain)
sensory aspect of language
orientation
self-perception
Temporal lobe is responsible for
Processing auditory information
Occipital lobe is responsible for
Processing visual information
Arterial supply to the brain
internal carotid arteries
vertebral arteries
- form circle of willis
Limbic lobe
Amygdala
Hippocampus
Mamillary body
Cingulate gyrus
Main functions of limbic lobe
Memory
Emotion
Motivation
Reward
Learning
Insular cortex
located deep within lateral fissue
Functions of insular cortex
Visceral sensations, Visual-Vestibular integration
Autonomic control, Auditory processing
Interoception
Layers of the head
SCALP
S- skin
C- connective tissue
A- aponeurosis
L- loose areolar connective tissue
P- periosteum
3 layers of meninges
Dura mater
Arachnoid mater
Pia mater
Dura mater
Thick, protective. Made of periosteal and meningeal layer
Outermost periosteal layer is adherent to bone, innermost meningeal layer part adherent to arachnoid mater
Space in between parts forms venous sinuses
Arachnoid mater
Thin, transparent, membrane attached to underside of dura
subarachnoid space
space between arachnoid mater and pia mater containing CSF
Pia mater
delicate membrane closely adherent to brain and spinal chord
Epidural haemorrhage CT
venticles not visible
gyri and sulci not visible
due to high compression in skull
between periosteal layer of dura and skull
Subdural haemorrhage CT
Ventricles visible
gyri and sulci visible
blood less dense - venous bleed in subarachnoid space
Layers of spinal meningeal system
meningeal dura
arachnoid mater
pia mater
CSF
occupies subarachnoid space, ventricular system and central canal of spinal cord
What cells produce CSF
ependymal cells in choroid plexus of ventricles
500ml made per day
~150ml flows in at any given time
Where is CSF reabsorbed
via arachnoid villi (granulations) in superior sagittal sinus
Ventricular system of brain
(superior to inferior)
lateral ventricles
interventricular foramen
3rd ventricle
cerebral aqueduct - connects 3rd to 4th ventricle
4th ventricle
central canal
CNS flow
Lateral ventricles
3rd ventricle
Cerebral aqueduct
4th ventricle
subarachnoid space via lateral and median foramen
venous sinus via arachnoid villi
CSF vs blood
CSF has fewer cells, proteins and potassium ions
Lower pH and less glucose
Function of CSF
shock absorbing
waste removal
supplies neurones with nutrients
what connects the right and left cerebral hemisphere
corpus collosum
Spinal cord
segments :
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal
each segment gives a pair of nerves that emerge through intervertebral foramina
nerves C1-7 emerge above respective vertebrae and from 8th nerve emerge from below vertebrae
2 enlargements in spinal cord
cervical enlargement - provides innervation of upper limb
lumbar enlargement - innervation of lower limb
