Flashcards
Lecture 8
Cards in this deck (63)
- 1Sleep-Appears to be an active process (sleep centers in brain actively stimulate sleep)
-Person will normally pass from active (EEG = beta waves) to drowsy (EEG = alpha waves) into sleep stages
-Four general stages of slow wave sleep
-Slowest and deepest is "slow delta wave sleep) - 2As a person falls asleep there is a gradual transition in the EEGCortical neurons make a gradual transition from firing independently low voltage waves to firing in synchrony (producing synchronous higher voltage waves on the EEG during slow wave sleep)
- 3There is a gradual transition fromone sleep stage to the next
- 4A person will cycle through sleep stagesSeveral times throughout the night
- 5Delta wave sleep-Slowest waves
-Begins approximately 30-45 minutes after you fall asleep
-very restful deep sleep
-decreased heart rate, blood pressure and body temperature
-increased parasympathetic stimulation
-very difficult to arouse person in sleep - 6Delta wave sleep lastsabout 10-15 minutes
-the brain waves start to gradually increase in slow wave frequency stages and then person makes transition to REM sleep - 7Why is the first 3-4 hours of sleep usually your deepest most restful sleep-go through 2 periods of delta sleep per night (about 1.5 hours between delta stages)
- 8REM sleep-Rapid eye movement sleep, occurs during this sleep stage (eye muscles contract)
-Period last approximately 5-20 minutes
-usually occurs every 1-1.5 hours of sleep
-normally have approximately 4-5 periods of REM per night - 9Why is REM often called "paradoxical sleep"Cerebrum is active, person is not aware of or responding to the environment
-most muscles of the body are inactive - 10EEG during REMSimilar to alert person (high frequency, beta like activity) but the brain activity is channeled in a way that individual is not aware of surroundings
-cortical activity is kept inside the brain
-skeletal muscles are inhibited, but twitches can occur
-heart rate, respiration and blood pressure change intermittently - 11Majority of dreamingOccurs during REM sleep (vivid dreaming)
-but some can occur during non-REM
-eye movements do not correspond to dreaming - 12If you wake a person from REM sleepPerson is usually alert and can recall dreams
-common to spontaneously awake during REM - 13Why do we need sleepAll vertebrates sleep
-total sleep deprivation can result in death
-Sleep appears to be much more important to the nervous system than other systems (e.g. muscles)
-Sleep deprivation results in irritability and sluggishness of though - 14By the time you reach 60 you have probably slept for?20 years
- 15Specific reasons for sleep are not clear,But it appears to be a restorative process, especially for the CNS
-sleep may allow neurons to recover from daily activities and regain maximal capabilities and restore homeostasis to CNS - 16Example of how sleep is important to the CNShypothesis suggests that sleep replenishes energy stores in astrocytes which can then be transferred to neurons during active periods
- 17Decreased activity during slow wave sleepMay also allow cells in the CNS to repair from damage occuring due to daily activities (damage to free radicals)
- 18Sleep may also be important forMemory
- may be important for memory "consolidation" memories from the day are put into long-term memory, possibly by the formation of new synapses - 19Sleep may help repairCellular damage that occurs during waking hours
- 20Mammals with what sleep more?The greatest metabolic rates
- 21Why have REM sleepMay be important during development of the nervous system in young (activity my enhance neural connections at synapses
-no clear reason for it
-some patient with brain damage have little or no REM sleep but seem to survive normally - 22Who spends more time in REM sleepChildren
In adults there is selective decrease in the release of certain neurotransmitters during REM, which may be beneficial for restoring those neurons to optimal capabilities for the day time - 23Anecdote regarding sleepRight and lef cerebral hemispheres of some dolphins have been shown to take turns sleeping, in that way dolphins can sleep while continuing to stay somewhat active
- 24Fatal Familial Insomina (FFI)exemplifies the importance of sleep
-Extremely rare disorder in which parts of the thalamus degenerate
-Appears to be an inherited, prion-based disease
-Occurs in middle-age to elderly
-progressive insomnia resulting in total lack of delta wave sleep and only bried episodes of REM
-experiences weight loss, dementia, wasting and death - 25NarcolepsyAbnormal condition in which person has irresistible sleep attacks during the day
-lasts about 5-30 minutes per episode
-suddenly falls asleep during a normal active state
-Emotional stimuli (e.g. laughter) can sometime initiate attack
-directly from awake to REM
-can include cataplexy in which person falls due to muscle paralysis - 26Sleepwalking-most frequent during slow wave sleep (not REM) early in the sleep cycle
-last from 30 sec to 30 min
-persons eyes are open and registering the surrounding
-person normally has little or no knowledge of sleepwalk upon awakening
-can have a genetic component - 27Sleepwalking has been hypothesized to be caused by"Immaturities" in the central nervous system and is more common in children than adults
- 28Sleep ApneaPeriodic lack of breathing during sleep (can be for a minute or more)
-Often caused by obstruction of breathing passge by soft tissue in back of throat (obstructive)
-Can also be due to abnormal control of breathing by CNS (central)
-oxygen levels in blood dangerously low
-CNS briefly arouses person in order to breath
-Normal sleep pattern is disrupted, no good nights sleep - 29ComaUnconsciousness from which person cant be aroused
-Can be caused by factors such as head injury (esp damge to brain stem and RAS), stroke, oxygen deprivation, overdose of drugs, carbon monoxide poisoning
-Widespred depression in the activity of the cerebral cortex
- - 30What does the cortex show in a comaSlow delta-wave like activity
- 31EpilepsySeizures
Uncontrolled (excessive) and/or abnormal activity in portions of the CNS
-Can be regional or can involve large portions of the brain
-Can occur with or without convulsive movements of the body
-Can result from brain tumors, lesions or no obvious reason
-Can be hereditary
-Can be initiated by a variety of factors, emotional stimuli (loud noises, flashing lights) - 32Grand Malepileptic seizure
Extreme discharge from many areas of brain
-Motor areas of brain are involved
-severe muscular spasms over entire body and loss of consciousness
-Few seconds to several minutes
Stops due to fatigue or via inhibition by neurons that were stimulated - 33Absence SeizuresPetit Mal seizures
-3 to 30 seconds of semi-consciousness (brief lapses of awareness)
-Can include twitching of certain muscles including blinking of eyes
-major motor areas of brain are usually not involved - 34Focal Epilepsy(focus refers to specific location)
Seizure is initiated by excessive discharge of neurons in specific area of brain and then spreads
-typical of many epileptic patients - 35Jacksonian epilepsyStarts in a specific area of somatomotor cortex and then spreads along motor cortex in a predictable manner with muscle spasms prgressing in a predictable fashion from one part of the body to the next as mapped on the motor cortex
- 36Epilepsy can be controlled in many patients by1. Drug therapy
-some epilepsy drugs enhance GABA activity (inhibitory neurotransmitter in CNS)
2. Surgery
-lesion or remove overactive area that is initiating attack - 37Autonomic Nervous System-Coordinates activity of viscera and blood vessels
-Not under direct voluntary control (i.e. subconsciously controlled) - 38Principle autonomic coordinating centers in the CNSHypothalamus and brainstem
- 39Two basic subdivisions of autonomic nervous systemSympathetic Nervous System
Parasympathetic Nervous System - 40Sympathetic Nervous System coordinates?-Coordinates stress-related activities
-Controls "fight or flight" response - 41Parasympathetic Nervous System coordinates?-Coordinates "vegetative" and/or "housekeeping" activities (digestion, rest and digest)
- 42SNS & PNS-Most organs are innervated by both systems
-Organ will be influenced simultaneously
-Each system has characteristic structures and neurotransmitters
-Both systems use a nerve pathway that consists of a two neuron chain that extends from spinal cord to the target organ (i.e. the effector organ") - 43Pathway between spinal cord and effector organ includes?Two neurons, preganglionic and postganglionic,
-they synapse in "ganglia" - 44Pre-ganglionic neurons in SNSEmerges from spinal cord in thoracic and lumbar spinal nerves and synapses with "postganglionic neurons" in ganglia
-Sympathetic chain ganglia run parrallel to the spinal cord (one chain on each side)
-Releases acetycholine
-effect on postganglionic neuron mediated by "nicotinic" receptors (stimulated by nicotine) - 45Postganglionic neuron in SNSTravels to target organ (effector organ) and releases norepinephrine
-Effect on norepinephrine of effector organ is mediated by "alpha" and "beta" receptors - 46SNS can also stimulatedirectly stimulate adrenal glands to release epinephrine and norepinephrine
- 47In PNS neurons travel... ExampleFrom CNS toward effector organ in cranial or pelvic nerves
-Vagus nerve (tenth cranial nerve) innervates a variety of organs in thoracic and abdominal cavities - 48PNS does notuse sympathetic chain ganglia, first synapse occurs in or near effector organ
- 49Preganglionic in PNSTravels to ganglion that is near or in effector organ and releases acetylcholine
- 50Postganglionic in PNSReleases acetycholine at effector organ
-Effect is mediated by "muscarinic" receptors
drug muscarine activates these receptors - 51Sympathomimetics ExamplesDrugs that mimic effects of sympathetic stimulations
-ephedrine and amphetamines (they enhance the release and activity of norepinephrine at the effector organ) - 52EphedrineChemical in the "Ephedra" plant species
-Herval extracts contain ephedrine
-worlds oldest medicine
-used in China to treat cold symptoms for thousands of years
-Over the counter, decongestant and asthma treatment
-Dietary supplement "stimulant" for weight loss and as energy booster - 53Adverse side effects of ephedrine-Increased heart rate, increased blood pressure, dehydration
-Currently banned in dietary supplements - 54Sympatholytics ExampleBlock sympathetic stimulation (e.g. block release or activity of norepinephrine)
-Beta blockers will block the effect of norepinephrine by attaching to and blocking beta receptors at the effector organ (used to treat high blood pressure and heart arrythmias) - 55ParasympathomimeticsMimic parasympathetic stimulates
- 56Parasympathomimetics Stimulate muscarinic receptor exampleMuscarine (substance extracted from certain mushrooms) or muscarine agonists
- 57Parasympathomimetics Stimulate muscarinc receptor treatmentSome used to treat glaucoma (e.g. pilocarpine stimulates the contraction of the ciliary muscles in eye which helps drain excess fluid from anterior chamber of eye)
- 58Parasympathomimetics block breakdown of ACh examples-Parathion (insecticide) and sarin nerve gas (permanent inhibitors and can be harmful or lethal)
-Donepexil (aricept) [example of a short-term cholinesterase inhibitor, used to treat Alzeheimer's disease, enhances the activity of ACh by decreasing the rate of its breakdown)
*Can also affect the SNS since the preganglionic neuron releases ACh - 59Parasympatholytics Example?Block the muscarinic receptors
-Atropine (derived from the belladonna plant Atropa bella-donna, one of the most toxic plants known)
Atropine and atropine like drugs are used to dilate puplis
Atropine-like drugs (e.g. scopolamine) are common in motion sickness pills, supress vomit reflex which is a parasympathetic reflex) - 60Drugs that equally affect both the SNS and PNS?Nicotine, stimulates nicotinic receptors at the ganglia
- 61Visual SystemDetects "light" which is electromagnetic radiation, but only in the range of 700-400 nm in wavelength (i.e. visible light spectrum ROYGBIV)
- 62Eyes detect light andthe the information is conveyed to and interpreted by the CNS
- 63Information from the eye is relayed throughThe thalamus and projected to the occipital lobe (i.e. the primary visual cortex)
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- Human Physiology Flashcards on Lecture 8, created by Erika Harkness on 09/07/2015.
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- Erika Harkness
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