Anatomy of the CNS Flashcards
Function of the CNS
Integrate received signals and perform higher cognitive functions
Function of PNS
Connects CNS to peripheral organs
Two types of matter in the brain. Which is located deeply and which superficially and why?
Grey - predominated by somas and dendrites
White - predominated by axons and myelinated fibres
Deep - white, superficially - grey
If axons are deep within the brain they can reach the parts they need more quickly, kind of like the shortest route
What matter is located deep and superficially n the spinal cord?
Deep - grey (somas and dendrites)
Superficially - white (axons and myelinated fibres)
Average brain mass and how many neurons in it
1.4 kg 100 billon neurons
What are the cerebral hemispheres separated by
Longitudinal fissure
What separates the frontal and parietal lobe
CENTRAL SULCUS
Site of primary motor cortex
Pre-central gyrus
Site of primary sensory cortex
Postcentral gyrus
What are sulci
More superficial depressions in the brain
What are gyri
Actual curves of the brain
Four lobes of the cerebral cortex
Frontal - primary motor area (voluntary movement)
Parietal - primary somatosensory area (proprioception, means space awareness). Behind frontal on top of temporal
Temporal - left and right lobe next to temple, primary auditory cortex (hearing), in between frontal and occipital on bottom of parietal TWO TEMPORAL LOBES ON EACH SIDE, other lobes are one joined one just separated by the longitudinal fissure
Occipital - most posterior, primary visual cortex
Functions of cerebrum
Sensation
Conscious thought and intellect
Memory
Complex movements
3 Primary types of tissue in the cerebral hemispheres (cerebrum)
- Cerebral cortex - outer brain matter or outer lining of the cerebrum
- Inner white matter - 3. basal nuclei, bundles of grey matter located deep in the brain
From where and to where does each side of the body receive/send information
Contralateral, with some exceptions
3 functional areas of the cerebrum cortex (first tissue found in cerebral hemispheres)
Motor, sensory and associated (multiple inputs and outputs, like the in-between sensory and motor neurons) areas
What is a cortical homunculus?
A neurological map off the areas of the human brain for processing motor and sensory information for different parts of the human body. eg. this area of the brain controls the toes
IMPORTANT - distorted representations eg. knee area is smaller than face area on brain due to more sensitive face
Which hemisphere is dominant for 90 percent of people and what does it control
LEFT - language, reasoning etc.
3 types of fibres in white matter and their function (second tissue found in cerebral hemispheres)
Association fibres connect different parts of the same hemisphere
Commissural fibres - connect grey areas of the two hemispheres, include anterior and posterior fibres as well, largest crops callosum
Projection fibres - project to subcortical regions (anything below the cortex), through these we receive sensory information and output motor signals
What are basal nuclei
Structures of grey matter deep within cerebrum, diencephalon and midbrain that receive inout from entire cerebral cortex.
Involved in controlling skeletal muscle, cognition and emotion
3 types of basal nuclei (third tissue found in cerebral hemispheres)
Caudate nucleus, putamen, globus pallidus
Where is the diencephalon located
Right under cerebral cortex in middle of scull
Three structures of diencephalon
- Thalamus - on top like a little ball picomprised of many clusters of nuclei to relay sensory information, decides where information from spinal cord and other nerves should go
- Hypothalamus - beneath the thalamus, involved in homeostasis endocrine hormone release, body temperature, emotions, sleep-wake cycles, thirst
- Epithalamus - location of pineal gland (release of melatonin) so controls sleep-wake cycles
3 structures in the brain stem
- Midbrain (mesencephalon)
- Pons
- Medulla oblongata
Function of midbrain
contains nuclei for visual and auditory information and controls reflexes for these senses
Function of pons
in middle, ascending, descending and transverse (link to cerebellum) tracts, involved in controls of respiration
Functions of medulla oblongata
brain joins spina cord at bottom of brain stem root, autonomic reflex sensor (hiccuping, vomiting, swallowing)
Cerebellum location and function
Hemispheres connected by vermis and connected to brainstem by cerebellar peduncles. Folds are called folia. Important for equilibrium, balance and coordination movement subconsciously
What is the spinal cord an extension of
Medulla oblongata
How long is the vertebral column
42 cm approximately, spinal cord is soft and is protected by the vertebrae
Where does the spinal cord terminate
Around L1-2 at the conus medullaris ( cone shaped structure)
What anchors spinal cord to skeleton where does it come from
From end of spinal cord (conus medullaris) a set of fibre extinctions called filum terminale. Anchors to a bone in the pelvis called coccyx
What are the spinal nerve roots called
Cauda equina
How many pairs of spinal nerves
31
How do spinal nerves connect to the spinal cord
Via roots
Two types of spinal roots and what information they process (eg. sensory or motor) Their location?
ventral - motor
dorsal - sensory
What are the Meninges? How many layers and what they are
A set of tissues that protect the brain. Coverings
3 layers - superficial dura mater, strongest
arachnoid - middle
pia mater - deep
How many layers does the dura mater have, where is it located and what is its function?
Two layers, strongest, fused to the periosteum (bones of the skull in most locations with some gaps for blood flow to occur).
Protection
What are dural folds what is their function
Reigons of dura mater that dip into the brain to help keep it in place, like a seatbelt
To what and with what does the arachnoid matter attach to
attached to Pia mater by hair like structures called trabeculae
What is in the space between the arachnoid mater and Pia mater
Cerebral Spinal fluid that helps nourish brain and provide protection
General anatomical features of Pia mater
follow contours of gyri and sulci (curves of brain) and rich with small blood vessels
Difference between meninges in spine to brain
Same three meninges however instead of dura mater fusing to skull, there is gap called the epidural space for fat and blood vessels
Where does cerebrospinal fluid lie
In space between Pia and arachnoid mater in the brain
Functions of CSF
support, nourish and cushion the brain and spinal cord ventricles
Where is CSF produced
in ventricles in a region called choroid plexus
Function of ventricles
hollow spaces with central region of brain that circle CSF around brain
number and location of ventricles
4 TOTAL - 2 lateral in each hemisphere,
3rd in diencephalon
4th between pons medulla and cerebellum
Three spinal cord traumas/disorders
Paralysis - damage of ventral roots
Plegia - transection (essentially cuts) of spinal cord at any level resulting in total sensory and motor loss eg. paraplegia between T1 and L1 lower limbs ; quadriplegia in cervical region, closer to brain the more severe the deficits
Motor neuron disease - Complete motor loss due to destruction of motor neurons in ventral regions and fibres in pyramidal tracts, death typically within 5 years not much information, symptoms include loss of ability to speak, swallow and breathe
