Central Nervous System Flashcards
What are the connective tissues surrounding the brain?
Dura mater, Arachnoid mater, pia mater
What are the 2 layers of the Dura mater?
Periosteal layer (periosteum): attached to skull Meningeal layer: true external covering of brain
What are the arachnoid granulations? What does it do?
Portions of arachnoid mater that extend through dura mater into dural sinuses; This is where CSF is returned to the blood after circulating through the CNS
What is the function of the CSF? Where is it found?
Located in subarachnoid space and ventricles; floats and cushions CNS, provides nutrients & removes waste
What produces CSF?
Continuously produced by ependymal cells of the capillary-rich choroid plexus
What is hydrocephalus? Why does it occur in babies?
CSF is overproduced and causes intracranial pressure and brain swelling; happens in babies because their skull is not fused so allow for swelling
What is white matter made of?
Myelinated axons
What is grey matter composed of?
Everything w/o myelin: dendrites, cell bodies, glial cells
What is the outer gray matter of the brain? Inner?
Cerebral cortex; nuclei
What is the outer white matter of the spinal cord?
Fiber tracts
What is the diencephalon comprised of?
Thalamus, hypothalamus, epithalamus
What is the mesencephalon made of?
Fiber tracts, superior & inferior colliculi
What is the metencephalon comprised of?
The pons and cerebellum
What forms the myelencephalon?
Medulla
What are the different types of fiber tracts?
Projection fibers, Commissural fibers, Association fibers
What are fiber tracts?
Bands of myelinated axons
What is the function of a projection fiber?
Allows communication between cerebral cortex and the rest of the CNS
What is the function of a commissural fiber?
Allows communication between right and left hemispheres
What is the function of an association fiber?
Allows from communication within different parts of the same hemisphere
What does the corpus callosum do? What kind of fiber tract is it?
Allows right hemisphere to communicate with left; commissural fiber
What are the 3 primary types of processing areas in the cerebral cortex? What are their functions?
Sensory areas: interpret sensory information coming into brain
Motor areas: dictate motor response
Association areas: apply meaning
What is a sulci? What is a gyri? What is a fissure?
Sulci = furrow, small indentations Gyri = Ridges Fissure = deep indentations
What is the central sulcus?
Divides frontal and parietal lobes
What is the longitudinal fissure?
Separates both cerebral hemispheres
What are the lobes of the cerebral cortex?
Frontal lobe, parietal lobe, occipital lobe, temporal lobe, insula
What are the functions of the frontal lobe?
Voluntary motor control; higher order cognitive functions (thinking, planning, decision making…)
What does the primary motor cortex do? Where is it found?
Conscious control of skeletal muscles; frontal lobe
What does the premotor cortex do?
Association area, plans and coordinated complex movements
What does the prefrontal cortex do? Where is it found?
Association area, Involved in personality, cognition, and intellect; frontal lobe
What is Broca’s area in control over? Where is it found?
Motor control of speaking; found in the left frontal lobe
What is the main function of the parietal lobe?
Input and interpretation of sensory information coming from somatic senses (touch, temperature, pain, pressure…)
What does the primary somatosensory cortex do? Where is it found?
Receives input from somatic sensory receptors of body; parietal lobe
What does the somatosensory association area do? Where is it found?
Interprets sensory information based on prior experience; parietal lobe
What is the function of the temporal lobe?
Receives and interprets sounds and sensory information from the inner ear and smell from the nasal cavity
What does the primary auditory cortex do? Where is it found?
Conscious awareness of sound; temporal lobe
What does the auditory association area? Where is it found?
Evaluation of sound; temporal lobe
What is wernicke’s area? Where is it found?
Recognition of spoken words; temporal lobe
What is the primary olfactory cortex? Where is it found?
Conscious awareness of smells; temporal lobe
What does the occipital lobe do?
Receives and interprets stimuli from retina of eye
What is the primary visual cortex? Where is it found?
Receives information coming from receptors in retina; occipital lobe
What is the visual association area? Where is it found?
Memories of images, analysis of color, form, and movement; occipital lobe
What is the function of the insula?
Visceral sensory cortex here, involved with the processing of emotions, self-recognition
What is the gustatory cortex? Where is it found?
Receives and interprets sensory information from taste receptors; insula
What is the basal nuclei? Where is it found?
Works with cerebal cortex to control motor movements; clusters of cell bodies deep to white matter of cerebrum
What is the striatum made of? Where is it located? What does it do?
Caudate nucleus + putamen; in the basal nuclei; interacts with substania nigra
What are the functions of the basal forebrain nuclei?
Arousal, learning & memory, motor control
What is the limbic system?
Considered the emotional brain
What is the amygdaloid body? What system is it a part of and where is it found?
involved in PTSD, memory of fear, regulates anger…; part of the limbic system; found in the temporal lobe
What is the job of the hippocampus?
conversion of short-term memories to long-term memories
What are the structures that are part of the diencephalon?
Thalamus, Epithalamus, Hypthalamus
What is the job of the thalamus?
Sensory information going to cerebral cortex must first go through the thalamus
What structure is found in the epithalamus? What does it do?
Pineal gland; secretes melatonin
What are the functions of the hypothalamus?
Hunger & thirst, Body temperature, Controls smooth muscle & cardiac muscle, and regulates the release of hormones from pituitary gland
What does the midbrain include? What do they do?
Superior colliculi: involved in visual reflexes
Inferior colliculi: Involved in auditory reflexes
What does the pons do?
“Bridge” between cerebral cortex and cerebellum, coordination of voluntary movements
What does the cerebellum do?
Coordinates muscle movements, involved with balance, fine motor control, and motor memory
What are the components of the brain stem?
Medulla, pons, midbrain
What are the functions of the medulla?
Basic life support functions (heart rate, blood pressure, rate of breathing)
What are the meningeal layers of the spinal cord?
Dura mater, arachnoid mater, pia mater
What is the epidural space? Where is it found?
Fat filled space around dura mater in the spinal cord
What are the 2 spinal cord enlargements? Why are they enlarged?
Cervical enlargement (upper limbs), Lumbar enlargement (lower limbs); a larger number of neurons are entering/leaving the spinal cord
Sensory information enters through the _____ side and goes ______.
Dorsal/Posterior; to the brain
Motor information enters through the _____ side and goes ____.
Ventral/Anterior; away from the brain
What are ascending tracts? Descending tracts? Commissural tracts?
Ascending:Sensory neuron axons
Descending: Motor neuron axons
Commissural: Interneurons that carry information from one side of the spinal cord to the other
What are the general steps of an ascending pathway?
- Sensory Receptors are activated
- Sensory Neurons synapse with interneurons within the dorsal horn
- Interneurons transport signal via ascending tracts to the the brain
What are the general steps of a descending pathway?
- Motor cortex initiates a response
- Interneurons transport signal to spinal cord
- Interneurons synapse within ventral horns
- Motor neuron transports signal to cells of action
What is the reflex arc? What are the different types?
An automatic and rapid motor response that doesn’t require input from the brain; Monosynaptic & Polysynaptic
