Physio Midterm Flashcards
(93 cards)
1
Q
Brain Protection
A
- Skull/Cranium
- Meninges
- Cerebrospinal Fluid (CSF)
2
Q
Spinal Cord
A
- Connected to the brain by the brain stem
- Long bundle of nerves
- Sends motor commands from the brain to the body, sends sensory information from the body to the brain, and coordinates reflexes
3
Q
3 Main Sections of the Spinal Cord
A
- Cervical Spinal Cord: sends nerves to the face and neck
- Thoracic Spinal Cord: sends nerves to the arms, chest, and abdomen
- Lumbar-Sacral Spinal Cord: sends nerves to the lower body
4
Q
Cauda Equina
A
- A bunch of nerves at the bottom of the spinal cord
5
Q
Types of Neurons in the Somatic Nervous System
A
- Sensory Neurons: carry signals from the outer parts of your body (periphery) into the central nervous system
- Motor Neurons: carry signals from the central nervous system to the outer parts (muscles, skin, glands) of the body
- Interneurons: connect various neurons within the body and spinal cord
6
Q
The Somatic Nervous System is made up of:
A
- Spinal Nerves: mixed nerves that carry sensory information into and motor commands out of the spinal cord
- Cranial Nerves: they are the nerve fibers that carry information into and out of the brain stem
7
Q
ASIA Impairment Scale
A
- A: complete; no motor, no sensory, no sacral sparing
- B: incomplete; no motor, sensory only
- C: incomplete; 50% of muscles LESS than grade 3 (can’t raise arms or legs off bed)
- D: incomplete; 50% of muscles MORE than grade 3 (can raise arms or legs off bed)
- E: normal; motor and sensory function are normal
8
Q
Amygdala
A
- Happiness and enjoyment
- Anxiety, irritability, and unease - withdrawal feelings = rewarding or aversive
- PTSD = HIGHER AMYGDALA AND LOWER VMPFC ACTIVATION
9
Q
Amygdala with Hippocampus
A
- Long term memories
- Episodic Memory: long-term memory that involves conscious recollection of previous experiences
- Long-term Potentiation: a process involving persistent strengthening of synapses that leads to a long-lasting increase in signal transmission between neurons
10
Q
Amygdala with Hypothalamus
A
- Sympathetic nervous response (fight or flight)
11
Q
Amygdala with Thalamus
A
- Unconscious fear processing
- Conditioned emotional response (classical conditioning)
- Unconscious response
12
Q
Structures of the Amygdala
A
- Lateral Nucleus: regarded as the sensory input gateway; located in dorso-lateral part of the amygdala
- Central Nucleus: key role in emotional response to aversive stimuli –> stress; damage = less stress hormones, ulcers, and stress-induced illnesses; stimulation = higher fear, agitation, gastric ulcers
- Basal Nucleus: major output pathways to cerebral cortex; projects to the VMPFC –> extinction of conditioned fear
13
Q
Ventral Tegmental Area
A
- Dopamine-rich nucleus that mediates reward system
- Located in midbrain, next to substantia nigra
- Sends dopamine to the nucleus accumbens, amygdala, hippocampus, and prefrontal cortex
14
Q
Ventromedial Prefrontal Cortex (VMPFC)
A
- Impulse control, courage, moral decision making
- Interface between emotional responses and control of complex behaviors
- Using emotional reasons to guide behaviors
- Courage = higher VMPFC activation
- Impulsive/emotional murderers = lower VMPFC activation vs. calculating/careful - typical brain patterns
- Antisocial personality disorder = 11% less gray matter in VMPFC
15
Q
Patient E.R.
A
- Bilateral damage of the VMPFC
- Excellent social judgement in verbal responses to hypothetical situations, expansive reasoning shared
- Real life situations = unable to prioritize between trivial and important decisions
16
Q
Neuron Structures
A
- Cell body (Soma)
- Dendrites
- Axons
- Myelin Sheath
- Terminal Buttons/Axon Terminals
17
Q
Cell Body (Soma)
A
- Contains the nucleus
- Shape varies in different kinds of neurons
18
Q
Dendrites
A
- A branched, treelike structure attached to the soma of a neuron
- Receives information transmitted across synapse
- Neurons converse with one another, and dendrites are recipients of these messages
19
Q
Axons
A
- Long, thin. cylindrical structures
- Axon Hillock: gate keeper of whether an action potential is strong enough
- Carries information from cell body to terminal buttons/axon terminal
- Action potential is basic message
20
Q
Terminal Buttons/Axon Terminals
A
- Buds at the end of a branch of an axon
- Forms synapses with another neuron
- Secretes chemicals called neurotransmitters
21
Q
Types of Glial Cells
A
- Microglia
- Astrocytes
- Oligodendrocytes
22
Q
Microglia
A
- Smallest glial cells
- Clean up dead cells
- Protect the brain from invading microorganisms/toxins
- Damage/toxins = microglial cells produce inflammatory mediators to call other cells to the injury –> promote and perpetuate the inflammatory response –> can worsen neurodegeneration
23
Q
Astrocytes
A
- Star shaped
- Neuron “glue” - holds them in place
- Engulf debris (phagocytosis)
- Provide nourishment via transfer of fuel - neurons use a lot of energy but cannot store it
- Provide electric insulation for unmyelinated neurons
24
Q
Oligodendrocytes
A
- Produces myelin in the form of a tube by wrapping itself around the axon
- Forms sheath in segments
- Episodic gaps = Nodes of Ranvier
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Action Potential
- Rapid burst of depolarization followed by hyperpolarization
- All or none law
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Depolarization
- Reduction of membrane potential (less negative inside)
- Lower in electrical charge = lower membrane potential
- Threshold of Excitation = set point to produce an action potential = -55mV
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Hyperpolarization
- Increase in membrane potential
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Post-synaptic Potential Types
- Determined by characteristics of postsynaptic receptors; type of ion channel they open
- Excitatory (EPSP): Sodium channel opened; depolarizing
- Inhibitory (IPSP): Potassium channel opened; Hyperpolarizing
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Glutamate
- "Go"
- Main excitatory neurotransmitter in brain and spinal cord
- Stored in vesicles and released from presynaptic neuron following an action potential
- Removed from synapse by excitatory AA transporters
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GABA
- "Stop"
- Inhibitory in the brain
- Stored in presynaptic vesicles
- GABA transporters re-uptake; aminotransferase deactivates
31
GABAA Receptor
- 5 binding sites
- Indirect agonists that bind the GABAA = benzos, some sleep meds, barbiturates, steroid hormones = sedating effects
- indirect antagonists at high doses = seizures
32
Glycine
- Inhibitory in the spinal cord and lower brain stem
33
NMDA Receptors
- 6 binding sites (4 on exterior and 2 located deep in the channel)
- Requirements for Glutamate to bind: Glycine must be attached; Mg must not be attached --> depolarized
- When channel is opened NMDA receptor allows sodium and calcium into cell --> depolarization
34
Dopamine Primary Effect
- Movement, attention, learning, and the reinforcing effects of substances
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Serotonin Primary Effects
- Involved in mood and pain regulation, and the control of eating, sleep, arousal, and dreaming
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Norepinephrine Primary Effects
- Vigilance/Attentiveness
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Oxytocin
- Post-Orgasm: in women, higher oxytocin = feelings of attachment and bonding
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Vasopressin
- Post-Orgasm: in men, higher vasopressin = vigilance and need to guard/protect partner
39
Key Structures of the Brain's Reward System
- Ventral Tegmental Area
- Nucleus Accumbens
- Amygdala
- Hippocampus
- Prefrontal Cortex
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Nucleus Accumbens
- Involved in all motivationally relevant stimuli = rewarding or aversive
- Interface between motivation and action
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Hippocampus
- Memory and learning
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Prefrontal Cortex
- Reasoning, problem-solving, impulse control, creativity, perseverance
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Positive Reinforcement
- Add something to the environment to increase behavior
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Positive Punishment
- Add something to the environment to decrease the behavior
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Negative Reinforcement
Remove something from the environment to increase the behavior
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Negative Punishment
Remove something from the environment to decrease the behavior
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Role of Stress
- Stress = higher corticotropin-releasing hormone (CRH)
- Strengthens amygdala
- Weakens the hippocampus and prefrontal cortex
- Results in: Negative emotional state, Lack of executive control (higher risk of relapse), Memory of relief/cravings
48
Studies of Stress
- 1/3 adolescents with reported abuse/neglect will develop SUD before 18
- 2-4x of those with PTSD developing chemical dependencies
- COVID-19 = 23% increase in AUD
49
Ethanol Absoprtion
- 20% stomach and 80% small intestine (several variables)
- Food inhibits absorption causing oxidation of alcohol
- 20-30% BAC absorbed fastest
- >30% irritates gastric mucosa --> slowed absorption
- IMPAIRED THIAMINE ABSORPTION
50
Ethanol Metabolism
- Primarily hepatic (90%)
- Alcohol dehydrogenase (ADH) oxidation (requires B vitamins)
- Metabolized to form acetaldehyde (carcinogenic, prevents, absorption of nutrients)
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Ethanol Excretion
- Urine
- Diuretic properties --> decreased nutrients and dehydration
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Ethanol Intoxication
- Consuming ETOH faster than liver can break it down
- 1 standard drink per hour
- 80% of individuals with AUD = thiamine deficiency due to lower vitamin absorption and higher thiamine use by ADH
53
Stimulant Pharmacokinetics
- Stimulants impact the brain's level of epinephrine/norepinephrine, dopamine, and serotonin
- Primary risk factors: Reduced seizure threshold; Higher BP, HR, HTB = higher risk of stroke, MI; Poor appetite, mood swings, anxiety, insomnia; Toxic levels = paranoia, psychosis
54
Nicotine Absorption
- Tobacco smoke - enters blood stream via lungs
- Smokeless tobacco - mucosal membrane of mouth, nose, or skin
- Reaches the brain in 7 seconds
- Mimics Ach = arousal, learning, memory, and emotions
55
Nicotine Effects
- Binds to nicotinic receptors --> changes cerebral metabolism
- Stimulates adrenal glands --> higher BP, HR, respiration, alertness and epinephrine
56
Nicotine Metabolism and Excretion
- Higher metabolism
- Metabolized by liver, kidneys, lungs = cotinine
- Excreted via urine
57
Cannabis Absorption
- Inhalation: peak plasma conc. 3-10 minutes; bioavailability = 10-35%
- Oral: peak plasma conc. ~ 120 minutes, bioavailability = 6-20%
58
Cannabis Distribution
- Rapidly to well-vascularized organs
- Accumulates in adipose tissue
59
Cannabis Metabolism
- Predominately hepatic
- Able to cross the placenta; released in breast milk
- Excreted through urine, feces, and sweat
60
Neural Effects of Ethanol
- OVERALL CNS DEPRESSANT
- Higher GABA and lower glutamate = slowed/inhibited NT firing --> sedation
- Higher serotonin and dopamine = relaxation and good mood
- Cerebellum --> loss of coordination and consciousness
- PFC --> decreased inhibition
- Blocks vasopressin = more urination and dehydration
61
Functions of Sleep
- To stay away from predators
- Conserve energy
- Allow body time to rest and regenerate
- Waste clearance
- Memory consolidation
62
Sleep Waves
- Synchronous Delta Activity: if the cells are active at about the same time their electrical messages are synchronized and appear as a large, clear wave in EEG data
- Desynchronous Beta Waves Activity: if neurons are active at different times, their electrical messages are desynchronized and appear as small, chaotic waveforms without a clear pattern in the EEG data
63
Roles of Slow-Wave Sleep in Learning/Memory
- Slow-wave sleep facilitates consolidation of declarative memories
- The brain rehearses newly learned information during slow-wave sleep
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Roles of REM Sleep in Learning/Memory
- REM is important for early neurological development
- REM sleep facilitates consolidation of nondeclarative memories
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Neural Chemicals Involved in Sleep
- Adenosine
- Histamines
- Acetylcholine
- Serotonin
- Norepinephrine
- Orexin
66
Adenosine
- Inhibitory
- Sleep deprivation = lower glycogen stores and higher adenosine = sleepiness
- Increases steadily during day producing sleepy feeling at night
67
Histamines
- keeps us awake
- antihistamines make us drowsy
68
Acetylcholine
- High during wakefulness and REM
69
Serotonin
- Low during REM sleep = limited movement
70
Norepinephrine
- Higher locus coeruleus firing = higher vigilance/focus
71
Orexin
High during alert or active waking, especially exploratory activity
72
Insomnia
- Effects 30% of adults
- Primary insomnia: difficulty falling asleep after going to bed or after awakening during the night
- Secondary insomnia: inability to sleep due to another mental or physical condition (e.g., pain, medication)
73
Narcolepsy
- Orexin-related neurological disorder
- Sleep attacks = overwhelming urge to sleep
- Cataplexy = sudden muscle weakness/paralysis
- Sleep paralysis = inability to move before onset of sleep or waking
- Treatment = modafinil, methylphenidate, SSRIs
74
REM Sleep Behavior Disorder
- Lack of muscle paralysis during REM --> acting out of dreams
- Can be comorbid with narcolepsy
- Typical onset 60 years+
- Believed to be neurodegenerative
- Treatment = clonazepam
75
Sleep Apnea
- 18 million Americans
- Difficulties sleeping and breathing at the same time
- Wake up gasping for airway and decreased slow wave activity
- Obstructive sleep apnea: due to narrowing of airway
- Central sleep apnea: brain does not signal need to breath
- Untreated: sig. deficits in attention, memory, and executive functions; increase risk of stroke, MI; in kids 2.5x risk of behavioral problems
76
Melatonin
- Produced by the Pineal Gland in response to evening/darkness about 2 hours before normal sleep time
- Serotonin is converted into melatonin
- Exogenous melatonin = take 1-2mg 30 to 1 hour before bedtime
- Light (especially blue light) negates melatonin effects
- Contraindicated in older adults with dementia and those with dementia
77
Emotional Response Components
Behavioral --> Emotional Response --> Hormonal; Autonomic
78
Kluver-Bucy Syndrome
- Can be caused by stroke, encephalitis, tumors, TBI, and even a lobotomy
- Damage to the bilateral amygdaloid nuclei (anterior temporal lobes) and hippocampus
- Results in: Absence of fear and anger response; psychic blindness/visual agnosia; hyper-orality; hyper-sexuality without sexual desire; binge eating disorder/bulimia; memory disorders
79
Urbach-Weithe Disease
- Rare genetic disorder
- Progressive damaging of neural tissue (via calcification)
- In the brain is confined to the amygdala complex
- 400 people worldwide (1/4 in South Africa)
- First symptom = weak cry/hoarse voice
- typical cognition across all domains
- Patient SM = lack of fear response
- Lack of pathway to VMPFC = no inhibition from typical fear inducing stimuli
80
Relationship between Heredity, Serotonin, and Aggression
- Higher correlations between monozygotic twins in antisocial and unemotional behavior
- 50-65% heritability --> believed to be due to gene modifications impacting serotonin synthesis/signaling
- Aggressive child-parent interactions = higher amygdala activation and aggression
- Serotonin inhibits aggression and risky behavior
- SSRIs = lower irritability and aggression
81
Emotional Expressions
- No differences between the expressions of congenitally blind, noncongenitally blind, and sighted athletes when expressing happiness
- Namibians and European-English = matched the same vocalizations with the correct story
82
Affective Blindness
- Those with damage to the visual cortex, can recognize facial expressions of emotions without conscious awareness of looking at a person's face
- "I can't see it" --> while matching it
83
Wernicke-Korsakoff Syndrome
- Wernicke's Encephalopathy (WE): ACUTE phase = confusion, incoordination, ataxia, decreased consciousness, memory deficits, abnormal gait
- Korsakoff Psychosis: can develop after WE or without - CHRONIC phase = severe short term memory loss, poor coordination
- Caused by chronic ETOH use and/or Thiamine deficiency
84
Alcoholic Neuropathy
- Peripheral nerve damage
85
Alcoholic Cerebellar Damage
- Deterioration or cerebellar neurons
- Chronic incoordination, slurred speech, jerky movements, tremor, nystagmus
86
Blood Brain Barrier
- Selectively permeable
- Area Postrema = weakest region (vomiting); has an additional barrier
- Blocks all molecules except those with: lipid soluble, specialized sugars and amino acids via facilitated diffusion, water molecules
87
Saltatory Conduction
- In myelinated fibers, depolarization and repolarization processes occur from one node of ranvier to the next instead of the entire area of the membrane
- Economic and speedy
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Sleep Stages (5)
1. Waking
2. NREM: Stage 1
3. NREM: Stage 2
4. NREM: Stage 3
5. REM
89
NREM: Stage 1 (N1)
- Transition between wakefulness and sleep
- Lightest stage of sleep
- Theta waves (4/7Hz)
- 2-5% of total sleep time
- Hypnic jerks
- Increased proportion suggests sleep fragmentation
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NREM: Stage 2
- About half the night
- Slowed HR, breathing, muscle activity, eye movements
- Reduced body temp
- Characterized by sleep spindles and K complexes
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NREM: Stage 3
- Slow-wave sleep
- Low frequency, high amplitude delta waves
- 20% TST
- Thought to be the most restorative sleep stage: memory consolidation, waste clearance
- Predominates first half of the night
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REM
- Rapid eye movement sleep
- Muscle paralysis
- Dreams
- Easily awoken from this stage
- Desynchronized EEG
- Absence of movement on EMG
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Sleep Cycles
- Each cycle lasts ~ 90 minutes
- Alternates from REM to NREM
- SWS predominates first half of the night
- REM predominates second half
