Central Nervous System Flashcards
What is grey and white matter in the brain?
Grey matter: Consists of unmyelinated somas, dendrites and axons
White: Mainly myelinated axons
What is the function of the spinal cord and its four regions?
Major pathways for information flowing back and forth between the vrain and the skin, joints, and muscles of the body
-Divided into four regions and each region is divided into segments:
-Cervical (8)
-Thoracic (12)
-Lumbar (5)
-Sacral (5)
-Coccygeal (1)
-Each segment gives rise to a bilateral pair of spinal nerves, each nerve splits into roots
What is grey matter in the spinal cord?
Dorsal root: carries sensory (afferent) information to CNS
Ventral root: carriers motor (efferent) information to muscles and glands
What is white matter in the spinal cord?
What is a spinal reflex?
-The spinal cord can act as the integrating center to initiate a response to a stimulus without receiving input from the brain
-Particularly important in body movement
What is the brain and its 6 major divisions?
-Organ providing human species with its unique attributes
6 major divisions:
-Cerebrum
-Cerebellum
-Diencephalon
-Midbrain
-Pons
-Medulla
What makes up the brainstem and what is its function?
-Oldest and most primitive region of the brain
-Ascending and descending tracts run through the brainstem
-Constain 11 of 12 cranial nerves: carry sensory and motor info for head and neck (not olfactory nerve)
-Contain many nuclei (groups of cell bodies)
-Involved in many basic processes in the body including arousal and sleep, muscle tone and stretch reflexes, coordination of breathing, blood pressure regulation and modulation of pain
-Consists of midbrain, pons, medulla oblangata and reticular formation
What is the function of the medulla oblangata?
-White matter contain all ascending somatosensory tracts and descending corticospinal tracts
-90% of corticospinal tracts decussate (crossover) at the pyramids
-Nuclei in the medulla control many involuntary functioning: including the cardiovascular center and the medullary respiratory center:
-Contains the vomiting center and deglutition center (swallowing)
-Coughing, sneezing and hiccupping
what is the function of the pons?
-Contains nuclei and tracts
-Relays information between the cerebellum and cerebrum
-Assists the medulla in the coordination of breathing
What is the function of the midbrain (mesencephalon)?
-Junction between lower brainstem and diencephalon (nuclei and tracts)
-Primary function is controlling eye movement
-also relays auditory and visual reflexes (movement of body in response to these stimuli)
-contains the substantia nigra
What is the function of the reticular formation?
-Extends throughout the brainstem: small clusters of neuronal cell bodies interspersed amongs tracts (ascending and descending)
-Important in consciousness, arousal, attention and alertness
-RAS inactivated during sleep, damage can induce coma
-Regulates muscle tone, assists in vital functions (HR, BP, Resp. rate)
-Projects/filters sensory info to cortex
What is the function of the cerebellum?
-Second largest brain structure
-Two cerebellar hemispheres
-Processes sensory information related to movement and coordinates the execution of movement
-Sends feedback signals to motor areas of the cerebral cortex, via its connections to the thalamus and pons helping to correct any errors and smooth movements
-Main area regulating posture and balance
What makes up the diencephalon
-Lies between the brain stem and cerebrum
-Two primary structure: thalamus and hypothalamus
-Two endocrine structures: pineal gland and pituitary
What is the function of the thalamus?
-Relay center
-Recieves sensory info from optic tract, ears, spinal cord and motor info from cerebellum
What is the function of the pineal gland?
Cyclically releases melatonin involved in circadian rhythm and sleep/awake
What is the function of the hypothalamus?
-The center for homeostasis
-Influences autonomic and endocrine function
What is the pituitary gland?
-Output of the hypothalamus
-Sits in a protected pocket of bone, connected to the brain by a thin stalk
-Posterior pituitary is nerual tissue
-Anterior pituitary is endocrine tissue
What is the function of the posterior pituitary?
-Neurohypophysis
What is the function of the anterior pituitary?
Hypothalamic-hypophyseal portal system
-Neurons in hypothalamus secrete, releasing and inhibiting hormones into the portal system
-Hormones are converted into new hormones that target specific parts of body
-Control growth, metabolism, and reproduction
What is the cerebrum?
-Largest and most distinctive part of the brain
-Grey matter includes: cerebral cortex, basal ganglia, and limbic system
-White matter includes tracts
-Areas of higher processing, “seat of intelligence”
-Two hemispheres divided into 4 lobes, connected by corpus callosum
-Frontal, Parietal, Occipital and Temporal lobe
What are basal nuclei? (ganglia)
-Gray matter of cerebrum
Three nuclei collectively termed the basal ganglia (nuclei):
-Globus pallidus
-Putamen
-Caudate nucleus
-Major job is regulating the initiation and termination of movement
-Receives input from cerebral cortex and provides output to motor portions of the cortex
What is the limbic system?
-Gray matter of cerebrum
-“Emotional brain” plays a primary role in a range of emotions, including pain, pleasure, docility, affection and anger
-also believed to play a primary role in learning and memory
3 major components:
-Cingulate gyrus (emotion)
-Amygdala (emotion and memory)
-Hippocampus (emotion and memory)
What is the cerebral cortex?
-Gray matter of cerebrum
-Outermost layer of the cerebrum
-Integrating center for the CNS
-Sulci are indentations, gyri are outward lumps
Functionally divided into three specializations:
-Sensory areas (translate sensory input into perception)
-Motor areas (direct skeletal muscle movement)
-Association areas (integrate formation from sensory and motor areas and help direct voluntary behaviours and deal with complex integrative functions)
