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.
Myopia =
Myopia = nearsightedness: Eyeball too long or lens system too round.
Astigmatism:
Astigmatism: an irregularity in the surface of the cornea or the lens which causes light to be bent irregularly. This shows up as an irregularity at the retina.
Cataracts
Cloudy or opaque area in the lens. The lens proteins denature and coagulate; it is also possible to have calcium deposits. Treated by surgical removal and replacement or “coke-bottle” lenses.
Glaucoma
A condition that can cause blindness or damage to the retina due to too much pressure in the eye (increased intraocular pressure).
cause of glaucoma
Often it is because the canal of Schlemm (which drains the aqueous humor out of the eye back into the blood) is blocked, but it can occur for other reasons,g., dilation can cause acute blockage in certain individuals. Peripheral vision is lost first.
glaucoma treatments
some treatments: osmotic diuretics, ACh agonists, β-blockers, THC = tetrahydrocannabinal—an active ingredient in marijuana)
Rhodopsin–retinal visual cycle:
The only point is that light hitting rhodopsin results in the production of a form of retinal, and rhodopsin is restored from retinal in the dark.
During the first few stages of the splitting of rhodopsin, a receptor potential is generated in the rods which causes excitation in the
retina
The receptor potential that excites the rod is very different from most other
The receptor potential that excites the rod is very different from most other receptor potentials. The decomposition of rhodopsin causes a hyperpolarization of the membrane of the rod (cone also).
the eye hyperpolarization is caused in the following way.
Normally in the dark, there is good deal of leakage of Na+ into the cell. Light shuts off the leak (closes a channel). Since Na+ is positive, stopping its entry makes the inside of the cell more negative = hyperpolarization.
If a person is in the light, the retina is bleached, that is,
much of the rhodopsin is decomposed to opsin and retinal. In the dark, most of this gets reconverted to rhodopsin.
So when the retina is dark-adapted, more rhodopsin is available to be affected by light =
the retina is more sensitive to light. This shift in sensitivity of the retina in dark adaptation and light adaptation contributes to our ability to have such a large sensitivity range:
All trans-retinal is in equilibrium with all trans-retinol =
Vitamin A.
. Lack of Vitamin A causes
first night-blindness and then blindness generally because it is needed in rhodopsin.
Bile duct obstruction can lead to what?
All trans-retinal is in equilibrium with all trans-retinol = Night-blindness and then blindness because of lack of Vitamin A absorption (fat-soluble, needs bile salts)
Rods:
Rods: very low light, very sensitive to light, greater sensitivity to light than cones
Cones:
Cones: brighter light, color vision, acuity vision, in fovea
Cones have 3 different proteins with different sensitivities to different parts of the spectrum, to
Cones have 3 different proteins with different sensitivities to different parts of the spectrum, to red, green or blue light.
fovea: all cones, color vision,
fovea: all cones, color vision, acuity vision (need a lot of photons hitting the retina to distinguish between one thing & another)
peripheral =
peripheral = more rods than cones. Rods = low light, high sensitivity, extrafoveal (peripheral vision gets better at night)
e . axons of ganglion cells =
e . axons of ganglion cells = optic nerve.
Ganglion cells exhibit inhibitory surrounds because of
Ganglion cells exhibit inhibitory surrounds because of lateral inhibition. They inhibit their neighbors which increases contrast sensitivity.
lesion to optic nerve (before chiasm)
blindness in the eye
lesion at optic chiasm
2= heteronymous(= opposite sides of the visual fields) hemianopsia, e.g.,
pituitary tumor. Each eye tested separately.
E.g., acromegaly
lesion past optic chiasm
3 = homonymous (= same sides of both visual fields) hemianopsia
Information from one area of visual space is sent via fibers to the
Information from one area of visual space is sent via fibers to the same cortex for analysis.
Many individual neurons in primary visual cortex can fire when either eye is stimulated, which is the basis of
binocular vision.
Primary visual cortical cells have much plasticity
Primary visual cortical cells have much plasticity early in life, less later, thus treatment for being “cross-eyed” (one form of strabismus) or having a “lazy eye” recommended to be done by about age 6 for best results.
Sound waves →
Sound waves → tympanic membrane → malleus → incus → stapes → oval window bulges → vibration transmitted into cochlea.
. Fluid pressure waves [perilymph →
. Fluid pressure waves [perilymph → Reissner’s membrane → endolymph wave causes tectorial membrane to contact hair cells] → → tectorial membrane and hair cells come in contact → receptor potential → impulses along 8th nerve → → temporal lobe
Different areas of cochlea respond to different frequencies and that
spatial map of sound frequencies is preserved to the primary auditory cortex.
Primary audit. cortex has different areas for
different frequencies
spatial map of sound frequencies is preserved to the
spatial map of sound frequencies is preserved to the primary auditory cortex. Primary audit. cortex has different areas for different frequencies.
Presbycuscis =
Presbycuscis = age-related hearing loss, often most marked at higher frequencies)
–Low frequency: apical cochlea, farther from oval window
deafness conduction
Conduction: from outer ear to hair cells, e.g., calcification or fibrosis of bones
–Sensineural or sensorineural or “nerve deafness”:
–Sensineural or sensorineural or “nerve deafness”: starting at hair cells on, e.g., destruction of hair cells by antibiotics.
there are about
1000 odorant receptors encoded by about 1000 different genes.
Smell and, to a lesser extent, taste, have a unique ability to trigger
Smell and, to a lesser extent, taste, have a unique ability to trigger long-term memories. An early defect in Alzheimer’s appears to be a reduced sense of smell. Suggested: early test for Alzheimer’s is testing for anosmia.
Also, there is a close relationship between smell and
sexual function in mammals
bitter –
bitter – (e.g., quinine, nicotine, caffeine, strychnine) alkaloids
sweet –
sweet – sugars, alcohols, some amino acids
umami –
umami – “savory, meaty, brothy”: carboxylate anion of glutamic acid
The sensation of taste is conveyed to the
The sensation of taste is conveyed to the parietal lobe of the cortex.
The immunosuppressant makes the animals sick. If later they are given saccharin:
The immunosuppressant makes the animals sick. If later they are given saccharin: They immunosuppress as if given a big dose of immunosuppressant.
chemotherapy
Then when they are going to the hospital for their weekly chemotherapy, they get “anticipatory nausea and vomiting”. At the time of the nausea and vomiting, no chemical is introduced into their bodies to cause this!
Lipophilic hormones:
steroids (including Vit. D + DHEA) and thyroid: Diffuse out, carried by plasma proteins, enter cells & bind to nuclear receptors, affecting genes. Longer latency. Tend to act longer.
hydrophobic hormones
Hydrophilic hormones: peptides, catecholeamines (NE, Epin., dopamine), indoleamines (serotonin, melatonin) Exocytosed from vesicles, dissolve in plasma, bind surface receptors, change G to an ion and/or affect a 2nd messenger such as Ca+ and/or cAMP.
A. Pars Intermedia:secretes
A. Pars Intermedia:secretes MSH (melanocyte–stimulating hormone) Stimulates melanin synthesis in humans
antidiuretic hormone: effects
Increases water reabsorption by kidney tubules, controls Na+ conc. & osm. Also is powerful vasoconstrictor – important in hemorrhage.
Increased osmolality (increased sodium) stimulates
Increased osmolality (increased sodium) stimulates osmo-receptors and causes hypothalamic neurons to increase its secretion. Loss of blood volume also has an effect.
Alcohol shuts off its effects at the kidney and inhibits .
Alcohol shuts off its effects at the kidney and inhibits its secretion.
Insufficiency: diabetes insipidus –
Insufficiency: diabetes insipidus – dilute urine, huge urine
output, thirst. Polyuria, polydipsia = drinking a lot. Can have inc. Na+ conc. in blood.
SIADH (syndrome of inappropriate ADH sec.) =
SIADH (syndrome of inappropriate ADH sec.) = Excess ADH. Low Na+ conc.
Oxytocin, also peptide - very similar in structure to ADH effects:
contraction of smooth muscle of uterus
ejection of milk from mammary gland
inhibits cortisol secretion, considered an anti-stress hormone
Regulation of oxytocin secretion:
: Nerve impulses from hypothalamus at end of gestation & upon feeding by the infant. Secreted in conditions of bonding, pleasure, social generosity, protectiveness? etc.
(Oxytocin starting to be used in autism. Caution! With hormones: “If you take it, you don’t make it.”
thyroid stimulating hormone (TSH)
Stimulates secretion of thyroid hormones
ACTH
Stimulates secretion of cortisol by adrenal cortex
follicle stimulating hormone (FSH)
In females, stimulates growth & develop. of ovarian follicles; promotes secretion of estrogen by ovaries. In males, required for sperm production.
LH
In females, responsible for ovulation & luteinization; regulates ovarian secretion of female sex hormones. In males, stimulates testosterone secretion
growth hormone
Primary hormone responsible for regulating overall body growth; important in intermediary metabolism
β-lipotropin:
β-lipotropin: lipolysis and steroidogenesis
Prolactin (PL)-
Prolactin (PL)-Enhances breast develop. & milk prod.
The releasing and inhibitory hormones =
The releasing and inhibitory hormones = hypophysiotropic hormones (tropic = turning toward or changing).
C. Growth hormone = somatotropin (peptide) effects
increases rate of protein synthesis and cell division in all cells
inc. mobilization of fatty acids from adipose tissue, & inc. fatty acid use for energy
decreases rate of glucose utilization throughout the body
Overall, GH enhances the
Overall, GH enhances the body protein, uses up the fat stores & conserves CHO. “Dieter’s dream hormone.”
Growth hormone further causes:
the liver to produce somatomedins. Somatomedin C = Insulin–like Growth Factor (IGF-I). The somatomedins act on cartilage and bone, and presumably other tissues, to promote growth. (All of growth hormone’s actions may be through the somatomedins.)
somatomedins
The somatomedins act on cartilage and bone, and presumably other tissues, to promote growth. (All of growth hormone’s actions may be through the somatomedins.)
growth hormone further causes
“a diabetogenic effect.” Presumably because of the decreased utilization of glucose, glucose blood levels rise (=diabetes = inc. urine). Also increased glucose in blood causes increased insulin which can cause burn out = depletion.
