Chapter10&11 Flashcards
What is homeostasis?
Balance or equilibrium
What does homeostasis depend on?
Active regulation
What role does the brain play in homeostasis?
Signals and coordination
What region of the forebrain is involved in various functions?
Hypothalamus
What do circadian rhythms influence?
Physiological systems
How often do internal clocks operate?
24-hour period
What physiological change occurs in the gut during the day?
Faster peristaltic waves
What happens to blood pressure at night?
Dips
What controls the shift between active and silent states?
Clock genes
What organism were clock genes first identified in?
Drosophila melanogaster
What do photoreceptors in the retina track?
Time signals
Why is the nudge important?
Syncs clock proteins
What happens to animals deprived of light?
Sleep/wake later
What ties the SCN to other body clocks?
Autonomic neural pathway
What does the SCN stimulate?
Paraventricular nucleus
What regulates the body’s sleep/wake cycle?
Orexin neurons
Which hormone influences sleep behaviors?
Melatonin
Where is the pineal gland located?
Between cerebral hemispheres
What sends signals to the pineal gland?
Electrical activity from SCN
What hormone does the pineal gland secrete at night?
Melatonin
What effect does melatonin have on alertness?
Reduces alertness
What triggers the stop of melatonin secretion?
Light exposure
What is the primary role of melatonin in relation to sleep?
Increases sleepiness
What body function does melatonin help synchronize?
Body’s clocks
What hormone peaks in the blood when waking?
Cortisol
What happens to core body temperature upon waking?
Drifts upwards
What does an increase in cortisol lead to?
Increased appetite
What can desynchronization of body clocks cause?
Health effects
What is a common example of circadian rhythm disturbance?
Jet lag
What can cause disturbance in circadian rhythms?
Late-shift jobs, blindness
What helps to reset circadian rhythms after jet lag?
Local day/night cycle
What health problems are associated with long-term circadian disruptions?
Weight gain, insomnia, depression, cancers
How do hormones deliver messages in the body?
More slowly, wider impact
What role does the brain play in hormonal signaling?
Regulates secretion and behavior
What do coordinated body clocks enable?
Physiological systems to work together
What oversees hormone production and release?
Hypothalamus
What gland is closely tied to the hypothalamus?
Pituitary gland
Which nuclei send axons into the posterior pituitary?
Paraventricular and supraoptic
What hormones are released by specific neurons in the hypothalamus?
Vasopressin or oxytocin
What hormone increases water retention and constricts blood vessels?
Vasopressin
What hormone promotes uterine contractions and milk release?
Oxytocin
Where do hypothalamic regions send axons?
Median eminence
What do activated neurons release?
Hormones into blood
Where do the releasing hormones travel?
To the anterior pituitary
How many anterior pituitary hormones are trophic?
Five
What do trophic hormones stimulate?
Endocrine glands
What does growth hormone stimulate?
Growth of bone and soft tissues
What does prolactin stimulate?
Milk production
What are the effects of anterior pituitary hormones?
Growth, metabolism, emotion
What systems do pituitary hormones influence?
Reproduction, hunger, thirst, stress
Where do many pituitary hormones affect receptors?
Inside the brain
What does GnRH stimulate?
LH and FSH release
What do LH and FSH stimulate?
Gonads to secrete sex hormones
What does the negative feedback loop in the hypothalamus regulate?
Hormone release
What is the outcome of the three-hormone cascade?
Mature eggs or sperm development
What maintains homeostasis?
Neuroendocrine system
What does the adrenal gland release?
Norepinephrine, epinephrine, cortisol
What hormone is released from the hypothalamus?
Corticotrophin releasing hormone (CRH)
What does CRH trigger in the pituitary gland?
Release of ACTH
What does ACTH stimulate?
Release of cortisol
Where does ACTH travel to?
Adrenal glands
How do sex hormones affect the hypothalamus?
Modify hormone release
Do sex hormones regulate feedback loops similarly in males and females?
Differently
What do male sex hormones induce?
Negative feedback loops
What hormones are reduced by male sex hormones?
Gonadotropin-releasing hormone
How often does the GnRH pulse peak?
Every 90 minutes
What do waxing and waning of GnRH maintain?
Testosterone levels
What is the pattern of female feedback on GnRH during the menstrual cycle?
Complex
Qué desencadena la maduración del óvulo?
Niveles de FSH
Qué induce a que los niveles de LH aumenten?
Aumento de los niveles de estrógenos
Qué produce el aumento repentino de LH?
Retroalimentación positiva
What occurs after ovulation regarding sex hormones?
Negative feedback on GnRH, FSH, LH
What happens to female sex hormone levels after ovulation?
Decrease
Do all hormones get regulated by the pituitary gland?
No
Where are many hormones released from?
Specific tissues
How do the brain receptors respond to hormones?
Do not regulate secretion
What hormones modify neural circuits?
Leptin and ghrelin
What do leptin and ghrelin regulate?
Food intake and energy balance
What effect do leptin and ghrelin have?
Affect hunger
What does ghrelin do?
Activates hunger circuits
When is ghrelin released?
When stomach is empty
What does leptin help maintain?
Body weight range
Where is leptin produced?
Fat cells
What does leptin do when it binds to neurons in the hypothalamus?
Suppresses hunger
What happens to leptin levels as fat stores are used up?
Leptin levels decline
What are common stress reactions?
Faster breathing and heartbeat
Why did stress reactions evolve?
To escape predators
What is the stress response?
Reaction to threats
What systems are involved in the stress response?
Nervous systems, muscles, metabolism
What is the goal of the stress response?
Defensive goal
What system primes the body for fight-or-flight?
Somatic nervous system
What redirects nutrients and oxygen to muscles?
Autonomic nervous system
What hormone does the sympathetic branch release?
Epinephrine
What effect does epinephrine have on the heart?
Increases heart rate
What does epinephrine do to arterial walls?
Relaxes them
What does the autonomic system’s parasympathetic branch restrict?
Blood flow to organs
What do neuroendocrine hormones affect?
Metabolic rate and sexual function
Where do glucocorticoid hormones like cortisol come from?
Adrenal cortex
How many muscles are in the body?
1070 muscles
What do stress hormones do?
Ramp up attention and learning
What does the body inhibit during stress?
Nonessential functions
What do adrenal glands release during chronic stress?
Epinephrine and glucocorticoids
What can chronic stress lead to in muscles?
Atrophy
How does chronic stress affect fat storage?
Increases storage as fat
What effect does chronic stress have on blood sugar?
Keeps high
What conditions can be worsened by chronic glucocorticoid exposure?
Diabetes, hypertension, atherosclerosis
How do hormones affect the immune system?
Reduce resistance to infection
What is a negative effect of chronic stress on brain tissue?
Impair memory formation
What do high levels of glucocorticoids inhibit?
Neuron growth in hippocampus
How do stress hormones affect decision-making?
Suppress neural pathways
What effect do stress hormones have on aging?
Speed deterioration
What complication can stress hormones worsen after a stroke?
Damage caused
How do stress hormones affect sleep?
Delay sleep
What can induced insomnia lead to?
Vicious cycle of stress
What do glucocorticoids influence during chronic stress?
Brain development
How can chronic stress in a pregnant woman affect her fetus?
Shift developmental trajectory
What role do glucocorticoids play in gene expression?
Transcription factors
What are the effects of high glucocorticoid levels during pregnancy?
Lower birth weights, developmental delays.
Why might glucocorticoids prepare a fetus for stressful environments?
Develop stress-sensitive ‘thrifty’ metabolisms.
What increases risk of chronic metabolic diseases?
Stress-sensitive metabolisms
Which diseases are linked to stress-sensitive metabolisms?
Obesity, diabetes
What can influence stress effects across generations?
Epigenetic mechanisms
What changes due to chronic stress?
DNA markers
What can changes in egg or sperm cells affect?
Offspring traits
What might chronic stress affect in humans?
Gene inheritance
What illnesses may be linked to changes in genes?
Cancer, obesity, etc.
What negative effects can chronic stress have?
Brain function
What percentage of people with autism have normal or above-average intelligence?
More than 40%
What are common comorbid conditions with autism?
Mood disorders, ADHD, OCD
Is autism considered a spectrum condition?
Yes
What are the two main criteria for diagnosing ASD?
Impaired social communication and repetitive behaviors
How do some adults view their autism?
As a strength
What might people on the autism spectrum struggle with?
Social communication
Prevalence of ASD in American 8-year-olds
1 in 68
ASD prevalence trend since 1970s
Risen dramatically
Diagnosis rate disparity in ASD
More in boys
Potential factors for ASD pattern
Underdiagnosis of girls
Environmental factors linked to ASD
Parental age, infection, prematurity
What is linked to an increased risk of autism in children?
Childhood Disorders
What has studies found about vaccinations and autism?
No connection
What drives autism at least partially?
Genetics
What do twin studies show about identical twins and autism?
Over 50% chance
Likelihood of autism in siblings?
Nearly one in five
Genetics of autism?
Very complicated
Role of genomic analyses?
Broadened potential genes
What contributes to the inheritance of most ASDs?
Many genes with small effects
Why are small effect genes hard to identify?
Genome-wide association studies
What type of variants are scientists currently examining?
Rare variants
What do rare mutations in single genes cause?
Intellectual disability and social dysfunction
Function of FMR1 gene?
Normal cognitive development
Role of PTEN gene?
Regulates cell division
Purpose of TSC1/TSC2 genes?
Control cell growth and size
% of people with fragile X syndrome affected?
50 to 60 percent
What percentage of people with tuberous sclerosis complex have ASD?
40 percent
What gene variant is associated with tumors in childhood?
NF-1
What percentage of NF-1 patients met criteria for autism?
10 percent
Which signaling pathway is influenced by ASD-related genes?
mTOR pathway
What is a potential treatment for autism according to the text?
mTOR pathway drugs
What is the role of PTEN mutations in mouse models?
Altered sociability, anxiety, repetitive behaviors
Which drugs can relieve behaviors linked to PTEN mutations?
Rapamycin, lovastatin
What is a challenge in autism genetics?
Too complicated for diagnosis
Are there biomarkers for autism?
No biomarkers available
How is autism currently diagnosed?
Behavioral analysis
How can autism be diagnosed more objectively?
Eye movements, neuroimaging
When can autism be reliably diagnosed?
Age 2
What age do most American children get diagnosed?
About 4½ years old
When do parents typically notice developmental issues?
Before first birthday
Why are earlier interventions hoped to be more effective?
More objective measures for diagnosis
What brain region is crucial for autism’s effects?
Cerebral cortex
What are the unclear aspects of autism?
Molecular causes and characteristics
What alterations are observed in the brain of people with ASD?
Subtle changes in white and gray matter
What have long-term studies found about some children on the autism spectrum?
Abnormally large brain volumes
What developmental issue is noted in toddlers with autism?
Unusual development and network inefficiencies
When does atypical activity in the cortex occur for people with ASD?
From childhood into adulthood
How might information be processed across brain networks in ASD?
Not integrated in the usual way
Have any medications proven to reverse autism?
No
What kind of drugs provide symptomatic relief?
Anxiety medications
What hormone has shown mixed social benefits?
Oxytocin
What are the only proven treatments for autism?
Behavioral therapies
When are interventions most effective?
Early interventions
What percentage of American children are diagnosed with ADHD?
11 percent
What age range was surveyed for ADHD diagnosis?
Ages 4 to 17
What percentage of ADHD cases continue into adulthood?
30 percent
What are the main characteristics of ADHD?
Inattentiveness, hyperactivity, impulsivity
How do ADHD symptoms differ from typical behaviors in young children?
More extreme, last longer
What difficulties do children with ADHD face in social settings?
Struggle to form friendships
What can ADHD symptoms reflect in school?
Behavior instead of ability
What are some executive functions affected by ADHD?
Following directions, finishing tasks
What is a consequence of ADHD in young people?
Lower graduation rates
What is the risk associated with ADHD?
Higher risk of suicide
What does ADHD diagnosis require?
Comprehensive evaluation
What types of evaluations are included for ADHD diagnosis?
Clinical interview, ratings
What other conditions can cause symptoms similar to ADHD?
Depression, sleep issues
What must attention and behavioral problems do to warrant an ADHD diagnosis?
Interfere with normal functioning
In how many contexts must behavioral issues be present for an ADHD diagnosis?
More than one context
What are some environmental risk factors for ADHD?
Early adversity, lead exposure, low birthweight
Do people with ADHD show obvious brain alterations?
No obvious alterations
What neurotransmitter is involved in ADHD?
Dopamine
Is there a cure for ADHD?
No cure
What are the treatments for ADHD?
Drugs, behavioral interventions
What types of ADHD medications are there?
Stimulants and non-stimulants
Why are long-acting formulations of ADHD medications used?
To avoid school interruptions
What may be needed to determine the right ADHD medication and dosage?
Specialist support
What factor influences the adjustment of ADHD medication dosage?
Child’s metabolism rate
Who usually diagnoses and treats ADHD?
Pediatricians
Effective treatments for ADHD include?
Support, exercise, meditation
What year was Down syndrome first described?
1866
Cause of Down syndrome?
Extra 21st chromosome
How many copies of the 21st chromosome in Down syndrome?
Three copies
What is mosaicism related to?
Trisomy not in every cell
How many people in the US have Down syndrome?
About 250,000
What is a major risk factor for Down syndrome?
Maternal age
How much more likely are mothers over 40 to have a child with Down syndrome?
8.5 times
What gene factor is associated with autism?
Dozens of genes
Facial features of Down syndrome
Flattened face, slanted eyes
Common physical traits in Down syndrome
Small hands/feet, short stature
Intellectual abilities in Down syndrome
Low to moderate
Down syndrome achievements
Some graduate, hold jobs
Common symptoms of Down syndrome?
Hearing loss, heart defects
When do individuals with Down syndrome typically develop Alzheimer’s?
In their 40s or 50s
Which chromosome is linked to Alzheimer’s in Down syndrome?
Chromosome 21
What gene on Chromosome 21 is associated with Alzheimer’s?
Amyloid precursor protein (APP)
What characterizes mosaic Down syndrome?
Milder symptoms, longer lifespan
What disorders might be related to energy metabolism?
Diabetes and Alzheimer’s
From where have scientists grown stem cells related to Down syndrome?
Fetuses with Down syndrome
What did researchers splice into stem cells with three copies of chromosome 21?
Gene to inactivate second X chromosome
What is dyslexia?
Difficulty with reading
What symptoms are associated with dyslexia?
Pronunciation trouble, poor spelling
When is dyslexia usually diagnosed?
Elementary school
What is dyslexia’s nature over time?
Persists lifelong
What areas of the brain are involved in decoding printed letters?
Many areas
Which brain region is involved in word recognition?
Word-form area
Which cortex shows less activity in people with dyslexia?
Left occipitotemporal cortex
What do researchers believe about brain differences in dyslexia?
Present before reading difficulties
How do people with dyslexia compensate for brain activity?
Rely on the right side
What have genetic analyses revealed about dyslexia?
Susceptibility genes identified
What do animal models suggest about dyslexia genes?
Affect brain cell migration
What condition commonly runs in families?
Dyslexia
What percentage of twins share dyslexia if one is diagnosed?
55-70 percent
What factors contribute to dyslexia?
Genetics and environment
What does treatment for dyslexia involve?
Behavioral and educational intervention
What exercises are used in dyslexia treatment?
Breaking words into sounds
What is a key early indicator of dyslexia?
Rapid automatic naming
Which skills are often impaired in dyslexia?
Naming and sound recognition
What can predict later reading skills in children?
Naming and sound recognition skills
What is epilepsy?
Seizure disorder
How many seizures indicate epilepsy?
Two or more
What percentage of American children have epilepsy?
1 percent
What percentage of American adults have epilepsy?
1.8 percent
What does the term ‘epilepsy’ mean?
Seize or attack
What causes seizures?
Irregular brain cell activity
How long can seizures last?
Five or more minutes
What are some symptoms of seizures?
Staring spells, shaking
What method is used to distinguish types of epilepsy?
EEGs
What determines the cause of seizures?
Symptoms and EEG recordings
What are generalized seizures?
Affect both sides of the brain
Examples of generalized seizures?
Absence, tonic-clonic
What happens during absence seizures?
Rapid blinking, staring
What are focal seizures?
Localized to one area
What can a simple focal seizure cause?
Twitching, change in sensation
What can complex focal seizures cause?
Confusion and inability to answer
What are secondary generalized seizures?
Begin localized, spread generalized
What can occur in patients with severe epilepsy?
Multiple seizure types simultaneously
Why is epilepsy considered a spectrum?
Many possible causes
What are causes of epilepsy?
Premature birth, brain trauma, genetic factors
What attributes suggest genetics in epilepsy?
Head size, movement disorders, family history
What problems can seizures cause?
Intellectual or psychiatric problems
What can some seizures suppress?
Growth of dendrites
What are treatments for epilepsy?
Controlling seizures with medication or diet
What is often enough to control seizures?
Single medication
What diet can help reduce seizures in about half of epilepsy patients?
Ketogenic diet
What might doctors recommend for severe cases not relieved by medication?
Surgery
What is split-brain surgery?
Cutting the corpus callosum
What does epilepsy represent?
A spectrum of disorders
What is the purpose of split-brain surgery?
Control seizures
