Exam 4 Part VI Flashcards
Alpha waves:
8-13 cps (=Hz)
Alpha waves: 8-13 cps (=Hz)
Awake, restful state generated thalamus → cortex, strongest in occipital cortex. Usually said to come from visual cortex when it’s generating its
own rhythm, not receiving input from
outside (eyes open – α is gone)
Beta waves:
Beta waves: above 14 cps→25→50→
Beta waves: above 14 cps→25→50→
During activation of CNS, attention to a particular activity, REM sleep or during tension (above parietal & frontal).
Delta waves: below 3.5 cps
In deep (slow-wave) sleep (can be generated by cortex alone)
Theta waves:
Theta waves: 4-7 cps Hippocampus, ant. cingulate: problem-solving, spatial learning, navigation, anxiety, but also some stages of sleep
The degree of activity of the brain is proportional to the frequency of
brain waves
Evoked potentials.
Usually sensory stimuli of some kind. Visual, auditory, somatosensory, etc. Used clinically to detect intactness and features of pathway to cortex.
Slow-wave sleep,
Slow-wave sleep, restful sleep, most during night in adults, fall into this after sleep deprivation. Sleep-walking is in this stage
REM sleep –
REM sleep – rapid eye movement sleep. About 25% of sleep in young adults recurring about every 90 min., usually associated with dreaming. (In neonates about 90% of sleeping is REM.) The EEG is like wakefulness (Beta waves). Loss of muscle tone is characteristic of this type of sleep.
Active theory of sleep:
some center or centers below the midpons actively causes sleep by inhibiting other parts of the brain.
[orexin =
[orexin = hypocretin, found in lat. hypothalamus, 1 type of receptor absent in narcoleptic dogs. Orexin knockout mice = narcoleptic.
Modafinil activates
Modafinil activates orexin neurons and keeps one awake]
C. Epilepsy
Characterized by uncontrolled, excessive activity in part or all of CNS.
Generalized seizures:
Generalized seizures: loss of consciousness:
Grand mal:
tonic-clonic convulsion of entire body
grand mal is a
generalized seizure
Most people who exhibit generalized seizures have a
Most people who exhibit it have a hereditary predisposition for it.
Factors that can precipitate epilepsy include:
strong emotional stimuli
alkalosis caused by overbreathing → hyperexcitability of neurons
drugs (insulin hypoglycemia)
fever
loud noises or flashing lights → resonating frequency
Traumatic lesions are also capable of eliciting
Traumatic lesions are also capable of eliciting grand mal. →scarring → excessive excitability locally spreads
Petit mal
Petit mal (absence seizures): a few seconds of unconsciousness,
Partial seizures:
Partial seizures: without loss of consciousness:
includes focal epilepsy
Focal epilepsy:
Focal epilepsy: can come from a scar, necrosis, tumor or unknown etiology. One type is a psychomotor seizure; it usually involves the limbic system of the brain.
Vegetative and endocrine control functions of the hypothalamus CV regulation
↑ P & HR (post. & lat.): “expansive” ↓ P & HR (preoptic): “contractive”
Body T regulation
(preoptic, anterior & post.) Preoptic: “contractive” = reduces heat. Posterior: “expansive” = increases heat
hypothalamus function
H2O regulation thirst (lat.): “expansive”
ADH (supraoptic nucleus = SON & paravent.) → posterior pituitary
Reg. of uterine contractility & milk ejection
(SON & paravent.) → oxytocin from post. pituitary
GI & feeding
Stim. of several areas → extreme hunger → ↑ eating (lat. is one area)damage causes loss of appetite. Neuropeptide Y → ↑ food intake. Lateral hypothalamus is one place with Y receptors
“anti-obesity center” –
“anti-obesity center” – called satiety center (ventromedial): Stimulation causes cessation of eating. Destruction causes obesity: can be caused by overeating, also without overeating (the latter suggests metabolism has changed).
Leptin (= thin) produced by
fat cells, circulates → ↓ food intake, ↑ energy consumption. Leptin receptors are found in one area of hypothalamus. (The hope was that) some obese people may have receptor or other problem downstream from leptin production.
B. Reward (“pleasure centers”) or approach areas,
avoidance areas Often stronger stimuli in reward areas → avoidance, rage Reward areas (lat. & ventromedial are some areas): rat will self-stimulate → starvation. Has been called the “do-it-again center” because of the high rate of stimulation.
sympathetic versus parasympathetic
sympathetic tend to function together, parasympathetic are more individualized.
pupil dilation
sympathetic
pupil constriction
parasympathetic
All preganglionic neurons release
All preganglionic neurons release ACh affect ganglionic nicotinic ACh receptors
norepinephrine
sympathetic
acetylcholine
parasympathetic
destruction of NT (sympathetic)
slow reuptake
destructio of NT (parasympathetic)
acetylcholine
Contraction of the ciliary muscles causes the ligaments attached to the lens to .
Contraction of the ciliary muscles causes the ligaments attached to the lens to relax.
Less tension on the lens = s.
Less tension on the lens = more spherical = greater focusing power = can look at near objects better. The parasympathetic causes the ciliary muscles to contract and allows for looking at near objects.
In a young person, the lens is relatively elastic. In an old person, it becomes relatively solid, partly because the lens proteins denature. The lens becomes nonaccommodating and the condition is
In a young person, the lens is relatively elastic. In an old person, it becomes relatively solid, partly because the lens proteins denature. The lens becomes nonaccommodating and the condition is presbyopia
The pupillary aperture
The greatest possible depth
of focus occurs when the aperture is small.
Emmetropia:
Emmetropia: In “well-measured vision”, if the ciliary muscles are relaxed, parallel light from distance objects are in focus at the back of the eye at the retina (tension is still on the lens; it is relatively flattened.)
Hypermetropia =
Hypermetropia = farsightedness: Usually the eyeball is too short or occasionally lens system is too flat.
