Neurvous System VIII Flashcards
Where and what is reticular formation?
Extends throughout brainstem
- small clusters of nuclei interspersed among tracts (ascending + descending)
Roles of reticular formation?
- consciousness, arousal, attention and alertness
- inactivated during sleep, damage can induce coma
- projects/filters sensory info to cortex
- minor: regulated muscle tone, assists in HR, BP, Resp rate.
What is cerebellum?
Second largest brain structure
Two cerebellar hemispheres
1/2 neurons in brain
Role of cerebellum?
- processes sensory info related to movement
- coordinated execution of movement (no errors and smooth)
- regulate posture and balance (vestibular)
- sends feedback signals to motor areas of cerebral cortex, via connections to thalamus and pons (aids in the proper movement)
Where is the diencephalon?
- between brain stem and cerebrum
What are two primary neural structures of the diencephalon?
Thalamus and hypothalamus
What are the two endocrine hormone secreting structures of diencephalon?
Pineal gland and pituitary gland (anterior and posterior)
What is main role of the thalamus?
Relay center
- receives sensory info from optic tract, ears, spinal cord and motor info from cerebellum and projects info to cerebrum for processing
What is role of pineal gland?
Cyclically releases melatonin involved in circadian rhythm and sleep/wake
What is main role of hypothalamus
Center for homeostasis
- influences autonomic and endocrine function
Homeostasis functions of hypothalamus?
- Maintain blood glucose concentrations
- Body temperature
- Controls body osmolarity
- Controls reproductive functioning
- Control food intake (full or hungry)
What is the pituitary?
Main hormonal output of hypothalamus
What is posterior and anterior pituitary made up of?
Posterior= neural tissue (extension of brain tissue)
Anterior= endocrine tissue (epithelial cells)
What is role of posterior pituitary (neurohypophysis)?
Extension of brain that secretes neurohormones made in hypothalamus
What is main role of anterior pituitary?
Complicated neuronal network involved in hormone secretion
- control growth, metabolism, and reproduction
What is the cerebrum?
Largest and most distinctive part of brain
- area of high processing, “seat of intelligence”
What does gray matter of cerebrum include
Cerebral cortex, basal ganglia, and limbic system (unmyelinated
What is white matter of cerebrum?
Tracts
Ascending: sensory
Descending: motor tracts connecting regions of cerebrum to pass info
What are 2 hemispheres of cerebrum divided into?
4 lobes, frontal, parietal, temporal, occipital
What connects two hemispheres of cerebrum?
Corpus callous
- massive # of tracts run between
What are three nuclei of basal ganglia (nuclei)?
Globus pallidus, putamen, caudate nucleus
What are role of basal ganglia (nuclei)?
Major job: regulating initiation and termination of movement
Receives input from cerebral cortex and provides output to motor portions of cortex
What are 3 major components of the limbic system?
Cingulate gyrus, amygdala, hippocampus
What is role of hippocampus
Involved in learning and memory
What is role of limbic system
“Emotional brain”
Role in range of emotions, including pain, pleasure, docility, affection, anger
Also role in learning and memory
What is cerebral cortex
Outermost layer of cerebrum
Integrating center of CNS
What are the indentations and outfoldings of cerebral cortex
Sulci and gyri
What are 3 functional specializations of the cerebral cortex?
- Sensory areas (translate sensory input into perception)
- Motor areas (direct movement)
- Association areas (integrate info from sensory and motor area, help direct voluntary behaviours)
What are areas of frontal lobe
Primary motor cortex and pre motor cortex
Skeletal muscle movement
What are areas of parietal lobe
Primary somatic sensory cortex and sensory association area
What are areas of occipital lobe
Visual association area and visual cortex
What are areas of temporal lobe
Auditory cortex and auditory association area
What is the gustatory cortex for
Taste
Wha is the olfactory cortex for
Smell
What is cerebral lateralization (dominance)?
- distribution of functional areas in two hemispheres is not symmetrical
- left hand will be right hemisphere dominant and vice versa
What is in left hemisphere?
Speech, language, writing, comprehension, analysis, calculations
What is in right hemisphere?
Creativity, spatial ability, imagination
What are conscious special senses?
Vision, hearing, taste, smell, equilibrium
What are conscious somatic senses (in skin + muscles)?
Touch, temperature, pain, itch, proprioception
What are subconscious somatic stimuli?
Muscle length and tension, proprioception
What are subconscious visceral stimuli?
- BP, distension of gastrointestinal tract, blood glucose, body temp, osmolarity of body fluids, lung inflation, etc.
What are sensory systems?
Sensory neuron with transducer (receptor), that converts a physical stimulus into an intracellular signal (change in membrane potential)
- through opening or closing gated channels
What are simple receptors
One peripheral axon that ends in free nerve endings
- pain/itch/temperature
What are complex neural receptors
Nerve endings enclosed in connective tissue capsules
Touch/proprioception
What are special senses receptors
Release neurotransmitter onto sensory neurons initiating AP
Special senses (except olfactory)
- non-neurons cell
What are sensory receptors
Gated channel or metabotropic receptors responsible for converting some physical stimulus to cellular response
Types of sensory receptors
Chemoreceptors, mechanoreceptors, photoreceptors, thermoreceptors
What is physical stimuli transduced into
Receptor potentials (graded potentials) and if reach threshold induce action potentials
