physio exam 3

3/17/25 

-muscles and their movements 

  • All animal movements depend on muscle contractions 

  • Smooth muscles  

  • Control the digestive system and other organs 

  • Skeletal muscles/striated muscles 

  • Control movement of the body in relation to the environment 

  • Cardiac muscles 

  • Heart muscles that have properties of skeletal and smooth muscles 

-muscle fibers 

  • Muscles composed of many individual fibers 

  • Area where neurons communicate with muscle fiber? 

  • Neuromuscular junction 

  • Synapse 

-neuromuscular junction 

  • The neurotransmitter released in the junction is acetylcholine 

  • Acetylcholine binds to ionotropic receptors 

  • When acetylcholine binds to the ionotropic receptors, it causes ligand-gated sodium channels to open 

-Antagonistic muscles 

  • What message is acetylcholine sending to muscles? 

  • Contract 

  • Movement requires alternating contraction of opposing sets of muscles 

  • Antagonistic muscles 

  • Flexor muscle 

  • Flexes or raises an appendage 

  • Extensor muscle 

  • Extends an appendage or straightens it 

-fast and slow muscles 

  • Skeletal muscle types range from: 

  • Fast twitch 

  • Fibers produce fast contractions 

  • Rapid fatigue 

  • Slow twitch 

  • Less vigorous contraction 

  • No fatigue 

-fast and slow muscles 

  • Slow twitch fibers 

  • Aerobic 

  • Require oxygen during movement  

  • Can work without fatigue 

  • Fast twitch fibers 

  • Anaerobic 

  • Breaks down glucose without use of oxygen 

  • Overuse of anaerobic metabolism results in fatigue 

-the cerebral cortex 

  • The primary motor cortex 

  • Precentral gyrus located in frontal lobe 

  • Important for complex movements 

  • Writing  

  • Speaking 

-muscle control from the primary motor cortex 

  • Axons from primary motor cortex 

  • Connect to brainstem and spinal cord 

  • Generate impulses that control muscles 

-initiating movement 

  • Specific areas of primary motor cortex control specific areas of opposite side of body 

  • Contralateral control 

  • Primary motor cortex 

  • Active during movement 

  • Controls outcome 

  • Rather than specific muscle 

-posterior parietal cortex 

  • Monitors body position in environment 

  • Damage to this area 

  • Difficulty coordinating visual stimuli with movement 

  • Stimulation posterior parietal cortex 

  • Report intention to move  

  • Increased stim  

  • Report movement despite none 

-supplementary motor cortex 

  • Organizes rapid sequence of movements in a specific order 

  • Especially according to internal preprogrammed plan 

  • Inhibitory if necessary  

  • Active seconds before movement 

-premotor cortex 

  • Active when motor sequences activated by external events 

  • Receives information about a target 

  • The pen I want to pick up is in front of me on the desk  

  • Integrates information about body position and posture 

  • My hands are currently on keyboard 

  • Organizes direction of movement in space 

  • How will I get from the keyboard to the pen 

-prefrontal cortex 

  • Active seconds before movement 

  • Important for considering probable outcomes of movement 

  • Damage? 

  • Disorganized movements 

-mirror neurons 

  • Active during both preparation of a movement and while watching someone else perform same/similar movement 

  • First reported in premotor cortex, later in humans 

  • May be involved in social behaviors 

  • Empathy 

  • Likely develop their properties through learning and are not likely the cause of imitation 

  • Not definitive 

-the cerebellum 

  • Brain structure often associated with balance and coordination 

  • More neurons in cerebellum than in all other brain areas combined 

  • Damage to cerebellum causes trouble with rapid movements requiring aim/timing 

-the cerebellum: more than just a subcortical structure 

  • Somatosensory function 

  • Active when using haptic perception 

  • Feeling an object to determine identity 

  • Active when object is moved across skin 

  • Strong response to violations in touch expectation 

  • Critical for aspects of attention 

  • Ability to shift attention and attend to visual stimuli 

3/19/25 

-the basal ganglia  

  • Group of large subcortical structures in forebrain 

  • Important for initiating spontaneous movements 

  • Compromises the following structures  

  • Caudate nucleus 

  • Putamen 

  • Globus pallidus  

  • Substania nigra 

  • What are the four parts of the basal ganglia, substantia nigra sends dopamine signaling to caudate and putamen 

  • Direct pathway = 

  • Responsible for making a movement 

  • Indirect pathway 

  • Inhibits inappropriate or competing movements 

-Parkinson’s disease 

  • Movement disorder characterized by  

  • Muscle tremors 

  • Rigidity 

  • Slow movements 

  • Difficulty initiating physical and mental activity 

  • Associated with an impairment in initiating spontaneous movement in absence of stimuli to guide action  

  • Symptoms also include 

  • Depression  

  • Memory and reasoning deficits 

  • Loss of olfaction 

  • Other cognitive deficits 

  • Studies show genetic link 

  • Small factor 

  • Environmental influences 

  • Exposure to toxins 

  • Traumatic head injury 

-immediate cause of Parkinson’s 

  • Death of neurons, especially in substantia nigra 

  • Gradual and progressive 

  • Substantia nigra usually sends dopamine-releasing axons to caudate nucleus and putamen 

  • Loss of dopamine= less stimulation of motor cortex 

  • Slower onset of movements 

-treatment of Parkinson’s  

  • L-dopa 

  • Primary treatment for Parkinson’s  

  • Precursors to dopamine 

  • Easily crosses blood-brain barrier 

  • Often ineffective and especially for those in late stages of disease 

  • Does not prevent continued loss of neurons 

  • Enters other brain cells, producing unpleasant side effects 

-use of fetal tissue in research  

  • Fetal tissue 

  • Cells fertilized for at least 8 weeks  

  • Before that, embryonic tissue 

  • Tissue commonly derived from elective abortions 

  • Embryonic tissues 

  • Tissues commonly leftover from in vitro fertilization treatments 

3/24/25 

-Huntington’s disease 

-rhythms of waking and sleeping 

  • Early psychologists view of biological rhythms  

  • Cycles of wakefulness and sleep dependent upon external stimuli  

  • Curt Richter (1922) 

  •  Body generates cycles of activity and inactivity 

-endogenous circadian rhythms 

  • Circannual rhythms 

  • All animals produce endogenous circadian rhythms 

  • Internal mechanisms operate on approximately 24-hour cycle 

  • Sleep cycle 

  • Frequency of eating and drinking 

  • Secretion of hormones 

  • Urination 

  • Sensitivity to drugs 

  • Body temperature 

-setting and resetting the biological clock 

  • Why do we have a biological clock? 

  • Keeps bodily processes in phase with outside world 

  • Rhythm determined using both internal and external cues 

  • Resetting our circadian rhythms is sometimes necessary 

  • Zeitgeber 

  • German meaning “time giver” 

  • Stimulus that rests circadian rhythm  

  • Most powerful zeitgeber  

  • Sunlight 

  • Time of meals 

  • Exercise 

  • Any kind of arousal 

  • Using zeitgebers other than sunlight 

  • Depression  

  • Irritability 

  • Impaired job performance 

-jet lag 

  • Disruption of circadian rhythm due to time zones 

-morning and evening people 

  • Cycles can differ between people 

  • Lead to different patterns of wakefulness and alertness 

  • Change as a function of age 

  • Young children are morning people 

  • Adolescents are often night people 

  • As an adult 

  • Partially depends on genetics 

-mechanisms of the biological clock 

  • Mechanisms of circadian rhythms 

  • The suprachiasmatic nucleus (SCN) 

  • Melatonin levels 

-the suprachiasmatic nucleus 

  • Main control center of circadian rhythms 

  • Located above (supra) optic chiasm 

  • Part of the hypothalamus 

  • Damage to SCN 

  • Erratic body rhythms  

  • Not synchronized to environmental light/dark patterns 

-the suprachiasmatic nucleus (SCN) and the circadian rhythm 

  • Circadian rhythms genetically controlled 

  • Unlearned 

  • Single cell extracted from SCN and raised in tissue culture 

  • Continues to produce action potential in a rhythmic pattern 

  • SCN transfer experiments 

-the suprachiasmatic nucleus (SCN) and the Retinohypothalamic Path 

  • Light resets SCN via a small branch of optic nerve 

  • Retinohypothalamic path 

  • Travels directly from the retina to the SCN 

  • Retinohypothalamic path 

  • Special population of ganglion cells 

  • Have their own photopigment called melanopsin 

  • Cells respond directly to light 

  • Do not require any input from rods or cones 

-melatonin 

  • SCN regulates waking and sleeping by controlling activity levels in other areas of the brain 

  • Pineal gland 

  • Endocrine gland located posterior (behind) to the thalamus 

  • Melatonin 

  • Hormone released by pineal 

  • Increases sleepiness 

  • Secretion begins 2-3 hours before bedtime 

  • Feeds back to reset biological clock through its effects on receptors in SCN 

  • Melatonin taken in afternoon 

  • Phase-advance internal clock 

  • Help you fall asleep earlier 

-sleep is special 

  • Coma 

  • Low level of brain activity 

  • Little to no response to external stimulus 

  • Unresponsive wakefulness syndrome 

  • Alternated between sleep and moderate arousal 

  • Open eyes 

  • Thrash 

  • No awareness of surroundings or purposeful behavior 

  • Minimally conscious state 

  • Occasional brief purposeful actions 

  • Respond to command 

  • Track movement with eyes 

-stages of sleep: EEG 

  • Electroencephalogram (EEG) 

  • Led to discovery of sleep stages 

  • Polysomnography 

  • Combination of EEG and eye-movement records 

  • Stage 1 sleep 

  • Beta waves 

  • Present when one is awake and alert 

  • Alpha waves 

  • Present when one begins a state of relaxation 

  • Stage 1 sleep 

  • EEG waves short, choppy, rapid 

  • Neurons out of phase with one another 

  • Brain activity begins to decrease 

  • Stage 2 sleep 

  • Sleep spindles 

  • 12-14 Hz waves during a burst that lasts a half a second 

  • K-complex 

  • Sharp wave associated with temporary inhibition of neuronal firing 

  • Shown to occur in response to: 

  • Low level sounds in environment 

  • Touches to skin 

  • Slow wave sleep: stage 3 and 4 

  • EEG recording of slow, large amplitude wave 

  • Slowing of heart rate, breathing rate, and brain activity 

  • Highly synchronized neuronal activity 

-paradoxical or REM sleep 

  • Rapid eye movement (REM) sleep 

  • Paradoxical sleep 

  • EEG waves irregular, low-voltage, fast 

  • Postural muscles paralyzed 

-brain mechanisms of wakefulness and arousal: reticular formation 

  • Reticular formation 

  • Extends from medulla to forebrain 

  • Responsible for arousal 

  • Damage to this area? 

  • Prolonged bouts of sleep 

-brain mechanisms of wakefulness and arousal: Pontomesencephalon 

  • Pons and mesencephalon 

  • Part of reticular formation 

  • Axons extend to hypothalamus, thalamus, and basal forebrain 

  • Release acetylcholine and glutamate 

  • Produce excitatory effects to widespread areas of cortex 

  • Stimulation of pontomesencephalon 

  • Awakens sleeping individuals 

  • Increases alertness in those already awake 

-brain mechanisms of wakefulness and arousal: locus coeruleus 

  • Small area within pons 

  • Usually quiescent 

  • Fires when exposed to emotionally relevant information 

  • Releases norepinephrine throughout cortex 

  • Wide ranging effect 

  • Enhanced attention and memory for important info 

-brain mechanisms of wakefulness and arousal: hypothalamus 

  • Contains neurons that release histamine 

  • Produce widespread excitatory effects  

  • Fire consistently when alert 

  • Fire at a lower rate when sleepy 

  • Cease firing when in non-REM or REM sleep 

  • Antihistamines produce sleepiness 

  • Orexin/hypocretin 

  • Released by neurons extending from hypothalamus to basal forebrain 

  • Necessary for maintaining arousal 

  • Orexin knock-out mice 

  • Alternate between waking and sleeping, even during wheel running 

-brain mechanisms of wakefulness and arousal: GABA and Acetylcholine 

  • Basal forebrain 

  • Involved both in sleep and wakefulness 

  • Some axons release acetylcholine 

  • Excitatory and increases arousal 

  • Released during wakefulness and REM sleep 

  • Release sharpens attention 

  • Some axons release GABA 

  • Inhibitory neurotransmitter 

  • Essential for sleep 

-sleep and the inhibition of brain activity 

  • GABA important for 

  • Decreasing temperature and metabolic rate 

  • Decreasing stimulation of neurons 

-sleep as a local phenomenon 

  • Sleep can be localized within brain 

  • Sleepwalkers 

  • Awake in one part of brain and asleep in others 

  • Most extreme version of sleep localization in brain 

  • Dolphins 

  • Lucid dreaming 

  • Dreaming but aware of being asleep and dreaming 

-brain functions in REM sleep 

  • Results from rather invasive sleep studies 

  • During REM sleep 

  • Activity increases in pons and limbic system 

  • Activity decreases in primary visual cortex, motor cortex, and dorsolateral prefrontal cortex 

  • Pons send messages to spinal cord 

  • Inhibits motor neurons that control large muscles 

  • Prevents motor movement during REM sleep 

  • REM regulated by serotonin and acetylcholine 

  • Drugs that stimulate acetylcholine receptors quickly move people to REM  

  • Serotonin interrupts REM 

-narcolepsy 

  • Sleep disorder characterized by frequent periods of sleepiness 

  • Gradual/sudden attack of sleepiness 

  • Occasional cataplexy 

  • Muscle weakness triggered by strong emotions 

  • Sleep paralysis 

  • Hypnagogic hallucinations 

  • Dreamlike experiences during sleep onset 

  • Difficult to distinguish from reality 

  • Runs in families 

  • Primary treatment 

  • Stimulant drugs 

-sleepwalking 

  • Runs in families 

  • Mostly in stages 3-4 of sleep 

  • Not dangerous to wake sleepwalker  

-sleep and memory 

  • Important role in enhancing learning memory 

  • Performance on newly learned task better the next day if adequately rested 

  • Patterns of activity hippocampus during learning were like those shown during sleep 

  • Suggests brain replays daily experiences during sleep 

-amounts of REM sleep 

  • Humans spend one-third of their life asleep 

  • About one-fifth is spent in REM 

  • Species vary in amount of sleep time spent in REM 

  • Most common in birds and mammals 

  • Percentage of REM sleep is positively correlated with the total amount of sleep in most animals  

  • Amond humans, those who get the most sleep have the highest percentage of REM 

-functions of REM sleep 

  • Brain may discard useless connections 

  • learned motor skills may be consolidated 

  • Disruption of sleep early in night 

  • Verbal learning disruptions 

  • Disruption of sleep later in night 

  • Motor learning disruptions 

3/31/25 

-sex and hormones 

  • Prenatal sexual differentiation begins with sex chromosomes 

  • Female mammal 

  • XX 

  • Male mammal 

  • XY 

  • During early prenatal development 

  • Mullerian ducts 

  • Precursors to female’s oviducts, uterus, and upper vagina 

  • Wolffian duct 

  • Precursors to other male reproductive organs 

  • Vans deferens and seminal vesicles 

  • Undifferentiated gonads 

-the SRY gene 

  • Gene on male Y chromosome responsible for masculinization 

  • Primitive gonads into testes 

  • Sperm-producing organs 

  • Developing testes produce androgens 

  • Increase testes growth 

  • Mullerian inhibiting hormone (MIH) 

  • Females= SRY gene 

  • Gonads develop into ovaries 

  • Egg producing organs 

-hormones in males and females 

  • Androgens and estrogens 

  • Classes of hormones 

  • Not hormones themselves 

  • Most famous androgen 

  • Testosterone 

  • Most famous estrogen 

  • Estradiol 

-steroid hormones 

  • Exert effects in three ways 

  • Binding to membrane receptors like neurotransmitters 

  • Entering cells 

  • Can pass through cell membrane  

  • Activate proteins in cytoplasm 

  • Bind to chromosomes in nucleus  

  • Activate or inactivate certain genes 

-different effects of sex hormones 

  • Organizational effects 

  • Occur at sensitive of periods 

  • Before birth and at puberty in humans 

  • Determine whether brain and body will develop male or female characteristics 

  • Activating effects 

  • Occur any time of life 

  • Temporarily activate a particular 

  • Pregnancy 

  • Menstruation 

  • Some cognitive effects 

-sexual differentiation 

  • Human sensitive period for genital formation 

  • Occurs during first trimester of pregnancy 

  • Depends mostly on level of testosterone 

  • Conversion to DHT responsible for external genitalia formation 

-organizing of sex hormones: estrogens 

  • Estradiol and other estrogens 

  • Not vital for early reproductive development 

  • Surge of estradiol necessary for secondary sex characteristics at puberty 

  • Absence of sex hormones 

  • Leads to female-looking external genitalia 

  • Independent of sex chromosomes 

  • XX individuals is lacking estradiol during early life 

  • Lower than average sexual interest in adulthood 

-sex differences in childhood behavior 

  • Childhood toy behavior 

  • Boys 

  • Cars, trains, balls and guns, and play roughly  

  • Girls 

  • Dolls and tea sets, and play cooperatively  

  • Preferences tend to be consistent over time 

  • Socialization or general preferences of each sex? 

  • Baby monkeys show similar preferences 

-sex differences in childhood behavior: prenatal hormones 

  • Girls exposed to high testosterone in utero 

  • Slightly elevated preference for typical boys’ toys 

  • Boys born to women with high phthalate levels (inhibit T production) 

  • Elevated interest in typical girls’ toys 

-actinvational effects of hormones 

  • The menstrual cycle 

  • Periodic variation in hormones and fertility over approx. 28. Days 

  • Hypothalamus and pituitary gland interact with ovaries to produce cycle 

-Females: FSH 

  • After end of a menstrual period 

  • Anterior pituitary releases follicle-stimulating hormone (FSH) 

  • Promotes growth of follicle in ovary 

  • Follicle nurtures ovum and produces estradiol 

  • Towards middle of cycle 

  • Follicle builds up receptors to FSH 

  • Follicle produces increasing amounts of estradiol 

-Females: FSH and LH 

  • Increased estradiol causes anterior pituitary to increase release of FSH and luteinizing hormone (LH) 

  • FSH and LH cause follicle to release an ovum 

  • Remnants of follicle release hormone progesterone 

  • Prepares uterus for implantation of a fertilized ovum 

  • Inhibits further release of LH 

-Females: pregnancy 

  • Estradiol and progesterone levels increase gradually throughout pregnancy 

  • No pregnancy 

  • Levels decline 

  • Uterine lining is cast off (menstruation) 

-Females: birth control pills 

  • Interfere with usual feedback cycle between ovaries and pituitary gland 

  • Combination-pill contains estrogen and progesterone 

  • Prevents surge of FSH and LH that would release and ovum 

  • Thickens mucus of cervix 

  • More difficult for sperm to reach egg 

  • Prevents egg from implanting in uterus 

  • No female birth control that prevents STI 

-gender identity and gender differentiated behaviors 

  • Gender identity 

  • How we identify and what we call ourselves 

  • All nurture, rather than nature 

  • Current advice 

  • Biological factors, especially prenatal hormones, also play role 

  • Sex differences 

  • Biological differences 

  • Gender differences 

  • Differences that result from people’s thoughts about themselves as male or female 

-individuals who are intersexed 

  • Anatomies intermediate between phenotypically male or female 

  • Causes 

  • Woman released two ova, each fertilized by a different sperm 

  • Ova united instead of becoming twins; rare 

  • Difference in sex chromosomes; atypical hormone patterns before birth 

-genital ambiguity 

  • 1 in about 5,000 has genital ambiguity to make sex assignment in US 

-chromosomal differences 

  • turner syndrome 

  • Lack or damage of second X chromosome 

  • Variety of medical problems 

  • Low thyroid hormone, heart defects, diabetes 

  • Will not menstruate or develop female secondary sex characteristics without hormone replacement therapy 

  • Klinefelter Syndrome (XXY) 

  • Results in  

  • Sterility 

  • Small testes 

  • Greater than average height (for males) 

  • Poor coordination 

  • Weak muscle tone 

  • “Supermale syndrome” (XYY) 

  • Criminal gene? 

  • Associated with  

  • Increased height 

  • Increased risk of learning problems 

  • Average IQ 

  • Acne 

-androgen insensitivity syndrome 

  • Androgen insensitivity or testicular feminization 

  • Individuals with XY chromosome pattern 

  • Production of androgens normal 

  • Lack androgen receptor that enables activation of genes 

  • Female phenotypic presentation 

  • Smaller than average penis or genital appearance of female  

  • Individuals tend to identify as women 

-discrepancies of sexual appearance  

  • 5-alpha reductase syndromme 

  • Genetic males can’t convert testosterone to dihydrotestoerone (DHT) 

  • Feminized genitalia at birth  

  • Penis develops during adolescence in puberty 

  • Many endorse male gender identity and heterosexual attractions 

-mental rotation 

  • Robust sex difference (male advantage) 

  • Test factors that exacerbate male advantage 

  • Time vs untimed 

  • 2D vs 3D 

  • Cultural factors 

  • Socioeconomic status 

  • Gender equity in participant country of origin 

-navigational tasks 

  • Magnitude of sex difference is smaller 

  • Evidence from animal studies suggests that sex difference can be erased through training 

-task of verbal memory 

  • Verbal fluency 

  • Producing words from a particular semantic category 

  • Name all the types of flowers you can in 30 seconds 

  • Verbal memory 

  • Recalling words from previously presented lists 

  • Recognizing words previously exposed to among a list of distractor words 

-memory for object location 

  • Female advantage 

  • Identifying new objects in an array after delay 

  • Identifying moved objects in an array after delay 

  • Not all studies agree on female advantage on the tasks 

  • Evidence that familiarity with objects is important 

-the case for a hormonal influence 

  • Evidence from CAH 

  • Women with CAH have better spatial performance than women without CAH 

  • Women with fraternal male twins 

  • Better spatial performance than controls 

  • Exposure to prenatal testosterone likely increases female spatial performance 
     

 

-sexual orientation 

  • Homosexual behavior occurs in many animal species 

  • Most men discover sexual orientation early 

  • Process slower for women 

  • Feminine-type behaviors during childhood and adolescence correlate strongly with homosexuality in males 

  • Masculine-type behavior in girls a poor predictor of sexual orientation 

-genetics 

  • One contributing factor in homosexuality  

  • Research studies of twins 

  • If one twin is homosexual, probability that other twin is as well is high (monozygotic twins) 

  • No single gene has been identified 

-prenatal influences 

  • Sexual orientation not related to adult hormone levels 

  • Homosexual men and women tend to have normal hormone levels for their biological sex 

-prenatal stress 

  • Mother's immune system may exert prenatal effects 

  • Mother may react to protein in a son and alter subsequent sons’ development 

  • Prenatal exposure to stress and alcohol may play a role 

  • Stress releases endorphins 

  • Antagonizes effects of testosterone on hypothalamus 

-brain anatomy 

  • Differences in brain anatomy between homosexuals and heterosexuals exist 

  • On average, the homosexual brain is shifted towards the opposite sex in some ways 

  • Several reported differences have no link to sexuality  

  • May relate to behavior differences