What is included in CNS (Central Nervous System)?
Brains, Spinal Cord
What two types of tissue are within the CNS, and their locations within the Brain vs. Spinal Cord?
White matter - predominated by axons of neurons, and fibres that are myelinated.
Grey matter - predominated by cell bodies and dendrites.
Within Brain; grey matter is on outside vs Within the Spinal Cord, with grey matter having butterfly shape on inside.
4 Divisions of Brain and locations
- Frontal (on front), primary motor area.
- Parietal, behind in crown of head, primary somatosensory area,
- Temporal, underneath all, primary auditory cortex (inline with ears).
- Occipital, above base of neck, primary visual cortex.
3 types of functional areas in Cerebral Cortex (Brain)
- motor areas: control voluntary movement
- sensory areas: conscious awareness of sensation
- association areas multiple inputs and outputs
3 types of fibres in white matter
Association fibres: different parts of hemisphere (outside U shapes)
Commissural fibres: Connect grey areas of two hemispheres (inner horizontal fibres)
Projection fibres: vertical tracts that connect the brain to inside structures (tree branches)
What is the basal nuclei?
They are a functional group of grey matter deep in cerebrum, diencephalon and midbrain, which receives input from entire brain and involves control of skeletal movement, and emotion
Describe 3 parts of Diencephalon
- Thalamus - enclosed 3rd Ventricle - relay sensory info like gatekeeper to brain, and involved in motor and limbic connections
- Hypothalamus - triangular space connected; for homeostasis, autonomic functions emotions, body temp, thirst, sleep-wake cycle, control of hormones for pituitary gland
- Epithalamus loopy thing connected to hypothalamus - pineal gland (melatonin), day/night cycles.
Describe 3 parts of Brain Stem
- Midbrain - visual and auditory info, controls reflexes for these nuclei
- Pons - ascending, descending and transverse tracts, involved in control
of respiration - Medulla Oblongata - joins to spinal cord, at foramen magnum of skull, is autonomic reflex centre (heart rate, respiratory rhythms, hiccup, vommit, swallow, etc.)
What is Cerebellum (little brain)?
- connected hemispheres by vermis and important role in equilibrium, balance and coordination of movement subconsciously
Two Main Features of Spinal Cord
- Is Major Reflex Centre: where reflexes are initiated and completed.
- is connected to spinal nerves through dorsal roots and ventral roots (our sensory and motor ganglions)
3 Layers of Brain coverings (meninges)
- Dura mater (superficial) - double layer and outer is fused to periosteum
- Arachnoid Mater (middle) - has CSF in subarachnoid space
- Pia Mater (deep) - delicate connective tissue which follows contours of gyri and sulci, rich in blood vessels
What is CSF?
- Cerebral Spinal Fluid, found in 2nd layer of Brain covering the brain and specifically holds the brain, also found in ventricles (lateral, 3rd and 4th) circulating the brain
- produced by choroid plexus found on roof of ventricles produces CSF
Coverings in Spinal Cord
Has same 3; Pia, Arachnoid, and Dura (separated from spine) mater, with epidural space surrounding the dura of the spinal cord.
Divide Peripheral Nervous System (PNS)
PNS
- sensory division (afferent)
- motor division (efferent) - then somatic vs. autonomic (divided into sympathetic and parasympathetic).
Preganglionic Fibres and Post Ganglionic Fibres in Parasympathetic vs. Sympathetic divisions
Parasympathetic - Fibres come from brain stem, with long preganglionic fibres, and short postganglionic fibres; location of ganglia (synapses) are close to effector organ.
Sympathetic - fibres originate from thoracic and lumbar spinal cord, with short preganglionic fibres and long postganglionic fibers, ganglia are close to spinal cord.
No. of Spinal pairs on Spinal Cord (hint* 5 sections, 31 pairs)
- 8 Cranial
- 12 Thoracic
- 5 Lumbar
- 3-5 Sacral (fused)
- 1 coccygeal (1-3 fused)
Spinal Nerves are what? (separated or mixed and why?)
They are mixed, with both dorsal roots (sensory) and ventral roots (motor) being connected to form spinal nerve.
