Week 2 neuro sl 62- Flashcards
What matter is CNS composed of? What is each?
Composed of gray and white matter.
-Gray matter is made of neuron cell bodies and dendrites, is found in the cortex of the brain, and in clusters called nuclei deeper within the brain
-White matter consists of axon tracts, whose myelin sheaths give them a white colour. The axon tracts underlie the cortex and surround the nuclei
What are the layers protecting/surrounding the brain?
Scalp, skull, meninges
What are meninges and what does it include?
Several tough layers of connective tissues
-Pia mater: Innermost membrane, clings to surface of brain/spinal cord, follows every fold
-Arachnoid mater: Middle layer, web-like/spidery appearance
-Dura mater: Has two layers, outer, toughest protective layer
What is the order of the layers around the brain?
PADSS
How is the spinal cord protected?
By the same meningeal layers as the brain
How does fluid also protect the brain? What are the two areas called?
Brain is protected by two fluid filled cushions against head trauma
-The outer cavity is the superior sagittal sinus (SSS), and sits under the dura matter
-The inner cavity is the subarachnoid space (SAS), located in the space between arachnoid and pia mater
What are cavities (ventricles) of the brain and spinal cord filled with for protection?
Filled with cerebrospinal fluid which is similar in composition to blood plasma
What are spinal nerves, how many are there and where?
Each nerve is a mixed nerve, containing both sensory and motor fibers. Fibers seperate near the attachment of nerve to spinal cord
There are 12 cranial nerves, but 31 spinal nerves
-8: cervical
-12: thoracic
-5:lumbar
-5:sacral
-1:coccygeal
Where does the spinal cord extend from, and where do nerves enter and exit the spinal cord?
-Spinal cord extends from brainstem to pelvic region, ending before the vertebral column’s end
-Nerves enter and exit spinal cord between the vertebrae
How do interneurons communicate and what happens?
Interneurons communicate along spinal cord, allowing afferent sensory stimuli to travel up or down it’s length
Explain upper and lower motor neuron damage in terms of knee jerk reflex test.
-If there’s lower motor neuron damage, reflex will be diminished
-If there’s upper motor neuron damage, reflex will be exaggerated because loss of inhibitory inputs means nothing will regulate the reflex because it’s damaged
What are the three primary vesicles of the brain that occur from conception to week 4 and explain.
Forms during embryonic development. By week 4 after conception, three sweellings appear the front of the neural tube which develops into brain.
-Prosencephalon (forebrain)
-Mesencephalon (midbrain)
-Rhombencephalon (hindbrain)
What are the 5 regions that were modified from the 3 primary vesicles? When does this occur?
5th week
-Prosencephalon: telencephalon and diecephalon
-Mesencephalon: mesencephalon
-Rhombencephalon: Metencephalon and myelencephalon
Slide on adult derivatives of brain!!
What is a hemmorhage stroke and an ischemic stroke?
Hemmorhagic stroke: Blood leaks into the brain
Ischemic stroke: Clot stops blood supply to an area of the brain
What do the midbrain and hind brain contain and why?
Midbrain and hindbrain contain many relay centers for sensory and motor pathways, and are important in brains control of skeletal movements
What is the cerebrum and what are the 5 regions?
Consists of left and right hemispheres, whihc are connected by corpus callosum. The cerebrum handles higher function (thinking, memory).
5 regions:
Frontal lobe, occipital lobe, parietal lobe, temporal lobe, insula
What does the occipital lobe do?
Vision and coordination of eye movements
What does the Frontal lobe do?
Motor control
What does the parietal lobe do?
Processes somatesthic sensation from cutaneous (skin), muscles, tendons, and joints
What does the temporal lobe do?
Interpretation and association of auditory and visual information
What does the insula do?
Deep brain region within lateral sulcus, between frontal and temporal lobes. Helps with memory, sensory integration and visceral responses. It processes smell, taste, sound, pain, etc
What is cerebral lateralization?
Each hemisphere of the brain processes different inputs, but they communicate through the corpus callosum.
What did experiments reveal about the hemispheres of the brain?
Experiments revealed that each hemisphere excels at certain tasks, leading to concepts of cerebral dominance, cerebral lateralization and handedness
What does damage to the right hemisphere cause?
Difficulty with spacial concepts and maps
What does damage to the left hemisphere cause?
Severe speech problems, but may still have ability to sing
What is this neurotransmitter associated with?
Adrenaline?
Fight or flight
What is this neurotransmitter associated with?
Noradrenaline?
Concentration
What is this neurotransmitter associated with?
Dopamine?
Pleasure
What is this neurotransmitter associated with?
Seratonin?
Mood
What is this neurotransmitter associated with?
Gaba?
Calming
What is this neurotransmitter associated with?
Acetylcholine?
Learning
What is this neurotransmitter associated with?
Glutamate?
Memory
What is this neurotransmitter associated with?
Endorphins
Euphoria
What is the cerebral cortex and what can damage to this area (prefrontal cortex) do?
Cerebral cortex is a gray matter layer covering the cerebrum and the cerebellum, divided into left and right hemisphere. Important in emotion and memory
-Damage to this area can cause severe impulsive, even sociopathic behaviour
What is the thalamus?
A relay centre for all sensory information (except smell) on it’s way to the cerebrum. Promotes alertness and causes arousal from sleep in response to strong sensory stimuli
What does the epithalamus contain?
Dorsal segment contains pineal gland which secretes melatonin (sleeping hormone and helps regulate circadian rhythm)
Where is the thalamus in the brain?
In 4/5ths of the diencephalon
Where is the epithalamus located?
Dorsal segment of the diencephalon
Where is the hypothalamus located?
Above the optic chiasm, and in the lowest part of the diencephalon
What does the hypothalamus do?
Is the site of master circadian clock (SCN), which receives light input to know how to function
Regulates daily processes:
-Hunger, thirst
-Body temp
-Hormone secretion (from pituitary gland)
-Sleep and wake cycles
What do the midbrain and hindbrain contain?
Contain many relay centers for sensory and motor pathways, and important in brain’s control of skeletal movements
What are the two dopaminergic systems in the midbrain?
nigrostriatal dopamine system, and mesolimbic system
What is the nigrostriatal dopamine system?
When does parkinson’s occur?
Involved in controlling movements
-parkinsons occur when dopaminergic neurons in substantia nigra degenerate
What is the mesolimbic system? What can overactivity in this region cause?
Involved in emotional reward. Substances like alcohol, amphetamines, cocaine, marijuana and morphine increase activity of dopaminergic neurons. Plays a role in addiction
Overactivity in this region may contribute to schizophrenia
What is the cerebellum composed of, and what does it do?
-Composed of over 50 billion neurons, and gray and white matter
-Monitors and refines motor activity initiated elsewhere. It does this by receiving input from proprioceptors (in joints, tendons and muscles) and motor signals from the cerebral cortex, helping to coordinate movement
What is the medulla required for?
Required for regulation of breathing, CV responses
What must pass through the medulla, involving the brain and spinal cord?
All ascending and descending fiber tracts providing communication between spinal cord and brain must pass through the medulla
What is the courchesne theory of overstimulation?
Autistic children seem antisocial because they shun external stimulation since the cerebellum can’t take it. Repetitive behaviour is calming ot thier brain
What are symptoms of aspergers and PDD?
some range of hyper focus, mild movement disroder, lack of social cues
