MaryBiraiCentralNervousSystem
Diencephalon
Cerebellum
CNS protection
Spinal cord
Brainstem
Cerebrum
Precentral gyrus: anterior to central sulcus. Primary motor complex. Control of voluntary movement
Postcentral gyrus: posterior to central sulcus. Primary somatosensory cortex: skin, muscles, joints (extremities), proprioception. Consciously aware of those sensations
Insula: gustation cortex. general visceral sensation ( stretch, discomfort, pain)
Broca area: on the left hemisphere. Controls motor movements of speech
Occipital lobe: location of visual cortex
Wernicke area: understanding of speech. Able to name objects and read words. In the left hemisphere
Temporal lobe: auditory, olfactory cortex. recognition of objects, words, & faces. Language comprehension. Emotional response and memory
Association tracts: connects parts of same hemisphere
Parietal lobe: Sensory part of brain, receives sensory info & processes it, Conscious awareness of a general somatic sensation - touch, pressure, temp
Commissural tracts: Corpus callosum - able to name objects and read words. Go from one part of the CNS to the other
Frontal lobe: Thinking & planning, making decisions, planning & initiating voluntary movement, memory
Projection tracts: communication between the cortex and the periphery. Either descend from cerebral cortex to more caudal parts or ascend to cortex from lower regions. Run vertically.
Thalamus: Is a paired structure
- Has several nuclei
- All sensory info on way to cortex goes through the thalamus except olfaction
- Its a relay station. There can be amplification or "tone down" the signal
Hypothalamus:
- Several nuclei
- Main visceral control center
- controls the autonomic nervous system with the help of grey matter in the brain stem
- regulates body temperature, hunger/thirst, sleep/wake cycles
- controls endocrine system
- involved with emotion
- controls motivational behavior: food & sex
- formation of memory
Epithalamus:
- forms part of roof of 3rd ventricle
- Houses the pineal gland (a small unpaired knob) which is a hormone secreting organ
- The pineal gland secretes melatonin & prepares us for sleep
Pons: 2nd region of brain stem
- grey matter of the pons
- reticular formation nuclei - involved with autonomic behaviors
- contains middle cerebellar peduncles
- contains Cranial nerve V, VI, and VII.
Medulla oblongata: continuous with spinal cord at level of foramen magnum
- cardiac center: heart
- vasomotor center - blood pressure
- respiratory center- breathing rate
- Pyramids: cortex of precentral gyrus. Motor output through pyramidal tracts.
- Decussation of the pyramids: pyramidal fibers that cross from one side of the brain to the other. Result is each cerebral hemisphere controls voluntary movements of opposite side of body
- cranial nerve nuclei: a place where cranial nerves connect with brain.
- 10/12 nerves connect with portion of brain stem. olfactory and optic nerves do not
Midbrain: between diencephalon and pons
- Motor movement - particularly movements of the eye & in auditory & visual processing.
- Cerebral peduncles: on ventral surface of brain. Composed of pyramidal motor tracts to spinal cord
- On dorsal aspect of midbrain, there is corpora quadrigemina
- 2 superior colliculi are involved in visual reflexes
- 2 inferior colliculi are involved in auditory reflexes
Filum Terminal: means "end filament"
- a long filament of connective tissue that extends from the conus medullaris and attaches to the coccyx inferiorly
- anchors the spinal cord in place so that it is not jostled by body movements
Anterior Roots: Ventral Roots
- Grey matter of the spine
- Motor 1/2 of the PNS
- Contains visceral (autonomic) motor and somatic motor neurons
- supplies muscles and glands
Cauda Equina: "horse's tail"
- Collection of nerve roots at the inferior end of the vertebral canal that resembles a horse's tail
Posterior Roots: Dorsal Roots
- Grey matter of the spine
- Sensory 1/2 of the PNS
- Contains Visceral sensory portion: interneurons receiving input from visceral sensory neurons
- Contains Somatic Sensory portion: interneurons receiving input from somatic sensory neurons
- axons reach the spinal cord
Conus medullaris: "cone of the spinal cord"
- Tapers at the inferior end of spinal cord.
Pia Mater: Gentle Mother
- 3/3 meninges
- Fibrous connective tissue
- Very vascular - capillary rich
Subarachnoid Space: Deep to the arachnoid membrane
- Filled with cerebral spinal fluid
- Holds arachnoid mater to pia mater
- Contains large blood vessels that supply the brain
- Arachnoid granulations allow cerebral spinal fluid to pass from subarachnoid space to dural venous sinuses.
Epidural Space
- Filled with cushioning fat and a network of veins
- Anesthetics are often injected here to block nerve impulses
Dura Mater: " tough mother"
- 1/2 meninges
- tough dense fibrous connective tissue
- has 2 layer
- perosteal layer - attaches to internal surface of skull bones ( this layer doesn't exist in spinal cord)
- meningeal layer - forms true external covering of brain (also found in spinal cord)
- subdural space has a little film of fluid
Arachnoid Mater
- 2/3 meninges
- Lies deep to the dura mater
- Subdural space is between the arachnoid mater and dura mater
- Subdural space is potential space that can be filled with blood or fluid as result of disease or trauma
Dural Sinuses:
- this is formed from the separation of perosteal and meningeal portion of Dura Mater.
- it is filled with deoxygenated blood
- Collect blood from brain and conduct it to the large internal jugular veins of the neck.
Superior Cerebellar peduncles
- efferent
- connect midbrain to the cerebellum
Middle Cerebellar Peduncles
- connects our cerebellum to the cerebral cortex
- efferent
- connects pons to cerebellum
Structure:
- Outer grey cortex, internal white matter (arbor vitae), and deep grey matter called nuclei
- Both grey portions are neuron cell bodies
Inferior Cerebellar peduncles
- Connect medulla oblongata to the cerebellum
- proprioception & equilibrium
- afferent
Function
- smooth & coordinate body movements with help of other brain parts.
- It also maintains posture and equilibrium