-
Sleep
- A state of changed consciousness or partial consciousness which can be aroused by stimulation
- Defined by EEG
-
EEG
- The printout of an electronic device that uses scalp electrodes to monitor the internal neural activity in the brain
- Record from the parietal or occipital lobes of an awake person
-
EEG paterns
- Undergo characteristic shifts in a sleeping person
- Reflect stages of sleep; duration of the series is typically ~90 minutes and pattern cycles 4 to 8 times per night

-
Alpha waves
- 8-13 Hz
- Decreased amplitude, slow waves, calm, relaxed, awake, eyes closed
-
Beta Waves
- 14-25 Hz
- Higher frequency, lower amplitude, a bit irregular, awake, alert, concentrating hard on something
- Aka EEG arousal
-
EEG arousal
- Normal to have beta waves during sleep cycle, but too much can cause not restful sleep
- Ex: sleep apnea can be a result of this
-
Theta Waves
- 4-8 Hz
- Early stage and REM sleep
- Abnormal in awake adults
- Higher amplitude, low frequency waves
- Seen in narcolepsy
-
Delta Waves
- <4 Hz
- Increased amplitude, further decreased frequency
- Ex: deep sleep (dreamless) and anesthesia
-
-
Sleep and brain stem activity
Sleep produces depressed cortical activity, but brain stem function continues (respiration, heart rate, blood pressure)
-
RAS
- Brain stem white matter, keeps you alert
- May regulate sleep; causing shifts in states of consciousness
-
Hypothalmus regulation
- Levels of wakefulness, using histamine as excitatory neurotransmitter and by inhibiting GABA and light dark cycles
- Stimulating release of melatonin from pineal gland
- More promoting of sleep during night time
-
Melatonin secretion
Starts naturally around 9:00pm and ends round 7:30am
-
Purpose of sleep
- Has a restorative function
- Gives the brain the opportunity to mentally sort through the days events
-
Quantity of sleep
- Daily requirements of sleep decline with age:
- Infants-16 hours
- Adults- 7 hours
- Elderly- <7 hours
-
What age group does not require stage 4 sleep?
>60 years
-
What percentage of sleep is REM in infants? in adults?
- 50% in infants
- 25% in adults
-
Types of sleep
- Defined in terms of EEG patterns
- NREM (non rapid eye movement): initial phase of sleep that has 4 stages
- REM (rapid eye movement): no individual stages
-
NREM Sleep or slow wave sleep
- Each stage gets slower in frequency and higher in amplitude
- Progression takes between 30-45 minutes
- Serotonin levels rise (promote sleep) and norepinephrine levels decline (NE maintains alertness)
-
Normal NREM sleep cycle and time
- 1-> 2-> 3-> 2-> 1-> REM
- Takes 90-120 mins
-
Stage 1 sleep
- Light sleep
- Eyes are closed; drowsiness and sleep begin
- Thoughts flit in and out and drifting sensation occurs
- Vitals are normal
- Increased frequency and decreased amplitude in waves
Alpha waves predominate and arousal is immediate; muscle jerks
-
Stage 2 sleep
- EEG patter becomes more irregular, arousal is more difficult
- More stable sleep begin
Transition to theta waves
-
Stage 3 and 4
- Sleep deepens
- Frequency of EEG drops and the amplitude increases
- Vitals begin to decline and muscles are relaxed
- Dreaming is common
- Growth hormone is released during this stage
More theta and delta waves
-
Slow wave sleep
- Deep sleep progresses into this becasue the EEG patter in dominated by delta (1-4 Hz) now.
- Vitals are at their lowest
- Skeletal muscles relax and sleeper turns every 20 mins
- Arousal is difficult and sleepwalking occur in this stage
-
REM sleep
- EEG patterns reverts through the NREM stages to stage 1 patterns, vitals increase, oxygen use is greater that awake (seems to be awake;not restful)
- Eyes move rapidly under lid but most other skeletal muscles are temporarily paralyzed
- Most dreaming occurs during this stage
- Most difficult to arouse but may wake spontaneously
- REM periods get longer during the night from 5 to 50 mins
-
Dreams in REM sleep
- NE and Ach levels rise causing this
- Occur later in the night/morning because REM gets longer as the night progresses
- Are a mental processing throughout the day
-
Learning
Acquisition and storage of information as a consequence of experience
-
Memory
- Relatively permanent storage and retrieval of previous experience. It is the ability to recall learned information
- Essential for learning and incorporating our experiences into behavior; part of our consciousness
-
Memory encoding
Neural processes that change an experience into a memory of that experience- the physiologic events that lead to memory formation
-
Three characteristics of memory
- Memory storage occurs in stages and is continually changing; relatively permanent
- Hippocampus and surrounding structures have major roles in processing
- Memory traces (chemical or structural changes that encode memories) are found widely distributed in the brain (synapses form as you form memories)
-
Two types of memory and brain areas involved
- Declarative memory-- hippocampus, amygdale and diencephalon
- Procedural memory-- sensory-motor cortex, the basal nuclei and the cerebellum
-
Declarative memory
- Retention and recall of conscious experiences that there be put into words (declared)
- Names, facts, and events
- Fact memory
-
Procedural Memory
- Memory of how to do things
- For skilled behaviors independent of conscious understanding like riding a bike
- Also involves learned emotional responses like fear of spiders
- Length of minutes to years
- Nondeclarative
- Skill memory
-
Episodic memory
- Explicit and declarative
- Length of minutes to years
- More situational like remembering what you had for breakfast and what vacation you took
-
Semantic memory
- Explicit, declarative
- Length of minutes to years
- Knowing facts such as your mother's maiden name
-
Long-term memory
- Limitless capacity
- Scores of phone numbers
- The ability to store and retrieve decreases with age
-
Working memory
- Length of seconds to minutes
- Short-term memory
- Words and numbers like a new phone number that needs to be written down or dialed
- 7-8 chunks of information such as a long sentence or a telephone number
- Quickly forgotten
-
Consolidation from STM to LTM depends on:
- Emotional state: learn best when alert--motivated, focused; NE released when we are excited or stressed out (endorphins interfere w/ learning or memory)
- Rehearsal: repetition
- Association: new info tacked onto old info thats already stored in LTM
- Automatic memory: not consciously formed (remember situations)
-
Crucial structures for incorporating and storing sensory perception are the:
- Hippocampus- limbic system
- Amygdala- limbic system
- Thalamus- diencephalon
- Hypothalamus- diencephalon
- Association areas (areas that surround and are associated with your senses)
-
Hippocampus
Oversees learning circuits and remembering spatial relationships
-
Amygdala
- Gatekeeper of memories
- Widespread connections with all cortical sensory areas, thalamus, emotional centers of the hypothalamus
- Crucial: Helps transfer fact memory to LTM
-
- Frontal lobe
- Stores semantic and episodic memories
-
- Motor cortex
- Involved in storing procedural memories
-
- Cerebellum
- Plays an important role in the storage of procedural memories
-
- Hippocampus
- Pivotal role in the formation of new long-term semantic and episodic memories
-
- Amygdala
- Vital to the formation of new emotional memories
-
- Temporal lobe
- Formation and storage of long-term semantic and episodic memories and contributes to the processing of new material in short-term memory
- Musical memory
-
- Prefrontal cortex
- Storage of short-term memories
- Behavioral center
-
Transport of sensory inputs in the brain
-
Amnesia
- Damage to either hippocampus or amygdala
- Results in only slight memory loss
- Destruction to both results in widespread amnesia
-
Anterograde amnesia
- Consolidated memories not lost
- New sensory inputs can't be associated w/old
- Keeps long term memories but no new ones-- can be from severe damage to amygdala and hippocampus
-
Retrograde amnesia
- Loss of memories formed in the distant past but can make new memories
- Ability to consolidate is there
- Amygdala may be damaged
-
Left cerebral hemisphere
- Deals with somatosensory and motor functions of the right side of the body and vice versa
- In 90% of the population, the left is specialized to produce language i.e. thinking about what to say or write, motor skills to speak or write and understanding written and spoken word
- Same with sign language
Absolutely no language on right brain (including reading and writing)
-
Language
- A complex code that includes the acts of listening, seeing, reading, and speaking
- Major centers are found in the temporal, parietal and frontal cortex and cerebellum
Males and females use slightly different brain areas for language processing
-
Wernicke's Area
- Temporal and parietal region on the left side that controls language comprehension, the individual's ability to understand written and spoken language
- Not the motor skills of speech but knowing what you and others are saying
Dictionary
-
Broca's Area
- Language area in the frontal cortex of the left side
- Responsible for articulation of speech, respiratory and oral musculature for speaking words
- Not involved in the comprehension, just the physical act of speaking
-
Damage to left hemisphere in early infancy or childhood
- Assignment of language function to a hemisphere of the brain can be changed if damage occurs in this stage of life
- Once the hemisphere has been decided (usually left determined at birth), damage to this hemisphere would cause permanent language deficits
-
Critical period for language development
- End of puberty or earlier
- This when exposure to language is essential, puberty is when the brain attains its structural, biochemical and functional maturity
- Talk to toddlers like people bc this is when language is truly developing
-
Memories/emotions storage
- Verbal memories are more apt to be associated with the left side
- Nonverbal memories like visual patterns, emotions in speech, sensations are associated w/ right side but same area
-
What happens if there is damage on the right side of the brain
- The person may not be able to understand what is meant by a text
- Differentiate between inflection tone i.e happy vs sad speech
-
Functions of the skeletal muscles
- Support body by allowing use to stay upright
- Allow for movement by attaching to skeleton
- Help maintain a constant body temp (shivering when cold)
- Assist in movement in the cardiovascular and lymphatic vessels
- Protect internal organs and stabilize joints
-
Muscle fibers
- Thousands of cells that make up skeletal muscles
- Elongated cells
- Have striated appearance and many nuclei per cell
- Filled w/lots of mitochondria and endoplasmic reticulum
-
Muscle
Refers to a number of muscle fibers bound together by connective tissue
-
Endomysium
Wraps each muscle fiber
-
Perimysium
Wraps each fascile (several muscle fibers bundled together
-
Epimysium
Wraps entire muscle
-
Tendon
- Connects muscle to bone
- Epimysium extending beyone muscle to interweave into periosteum
-
Insertion
Attachment on the moveable bone; pull insertion closer to the origin
-
Origin
Attachment on the immoveable bone
-
Ligament
Bone to bone, extensions of the connective tissue coverings found in muscle
-
Smooth muscle
- Involuntary in hollow organs and vessels
- Narrow cylindrical fibers
- Nonstriated
- Uninucleate
-
Cardiac muscle
- Involuntary found in the heart
- Striated
- Branched
- Generally uninucleate fibers
-
Skeletal muscle
- Voluntary muscle that is attached to the skeleton
- Very striated
- Tubular
- Multi nucleated fibers
-
Sarcolemma
- Muscle plasma membrane covering the skeletal muscle
- Na on outside; K inside
- Membrane is polarized at rest (-70mv); needs to be depolarized to activate the cell to contract
-
Sarcoplasm
- Cytoplasm of the muscle cell
- Large amounts of myoglobin
-
Myoglobin
- A red pigment that stores oxygen to let you exercise longer
- What changes when increasing endurance; more myoglobin=less you compensate by breathing bc cells hold more oxygen
- Red meat has more myoglobin compared to chicken
-
Sarcoplasmic reticulum
- Modified endoplasmic reticulum
- Regulates intracellular levels of Ca
- Stores and releases Ca2+Wraps each myofibril like a shirt sleeve
-
Yellow tube and blue tube
- Yellow: t-tubule runs up and down and is connected to the plasma membrane or sarcolemma
- AP is conducted into the muscle through this into the SR.
Blue: SR; runs horizontally and is connected to the t-tubules at the triads (where there is a t-tubule in between 2 blue tubes
-
Myofibrils
- Modified organelle of a muscle cell
- Contractile elements in muscle and run in parallel fashion
- Makes up about 80% of cell volume
-
Sarcomere
- A chain of these contractile units make up each myofibril
- Arrangement of dark and light bands within this is responsible for striations
-
Dark Bands
- A bands
- Each A band has a lighter midsection called H zone (only in relaxed state)
-
Light Bands
- I bands
- Each I band has a darker midsection called Z line
- Sarcomeres run Z line to Z line
-
Myofilaments
- Proteins that cause the banding pattern; even smaller structures within sarcomeres
- Thick and thin myofilaments are made of Actin and Myosin
-
Thick myofilament
- Composed of a protein called myosin
- Contain crossbridges (globular portion) which link thick and thin myofilaments during contraction
- This means the thick myosin heads attach to the thin filaments called a crosbridge to allow for contraction or shortening of the sarcomere

-
Thin myofilaments
- Composed primarily of Actin proteins-- looks like two strands of pearls twisted together
- Tropomyosin and troponin (regulatory proteins) are present on this
-
Tropomyosin
Protein strands on actin that block active sites on actin so myosin cannot bind to actin in a relaxed muscle
-
Troponin
Ca binds, changes structure, and causes tropomyosin to slide and expose myosin binding sites on tropomyosin
-
T-tubles
- At each junction between A and I bands
- Runs between the terminal cisterna or lateral sacs so triads are formed
- Conduct impulses to deepest regions of the muscle cell
- Where the Calcium is stored and released from
-
Sliding filament mechanism
- Thin filaments slide past the thick ones for an overall shortening of the fiber
- When muscle is stimulated to contract, the cross bridges attach to active sites on actin thin filament
- Crossbridge generates tension and pull the thin filament towards center of the sarcomere
- Muscle cell then shortens
- Requires calcium for myosin to attach to actin
-
Neuromuscular Junction
- Stimulation of a specific nerve to that specific muscle causes an AP to travel down nerve fibers resulting in release of Ach from axon terminal or boutons; exocytosis into synaptic cleft
- Ach diffuses across synapse and bind to nicotinic receptors located on motor end of plate
- Sodium ion gates open in motor end plate in response to Ach forming positive graded potential (End plate potential, EPP)
- If EPP is large enough, it will cause sodium voltage gates to open along the sarcolemma
-
Motor end plate
Trough-like part of the sarcolemma that helps to form neuromuscular junction, is highly folded to increase surface area which allows for more receptors
-
Motor Unit
- All of the muscle fibers supplied by a single neuron, many units per muscle
- Each can contract as a unit or group
- More that activate, stronger the force (recruitment)
-
Muscle twitch
- Brief contraction of all muscle fibers in a motor unit in response to a single AP in a motor neuron
- Simplest type of recordable muscle contraction
-
Components of muscle twitch
- Latent period
- Contraction
- Relaxation
- Refractory
-
Latent Period
- Brief period between stimulus applied and contraction
- Ca+ is released from the SR and myosin head begins during latent period
-
Contraction period
- Muscle is contracting
- Time depends on slow vs fast twitch
-
Relaxation period
Muscle fibers are returning to their uncontracted states, repolarizing
-
Refractory period
- After depolarization, a skeletal muscle fiber cannot be depolarized again for about 0.005 sec.
- Absolute refractory: muscle cannot contract even if stimulated; needs to be at least 1/3 complete
- Relative refractory: from the end of the absolute period to the start of a new depolarization
-
Skeletal muscle vs Cardiac muscle refractory period
- Skeletal= short
- Cardiac= long
-
Atonic contraction
- When you are sending constant stream of AP to muscle when you are flexing and holding it
- Allows you to contract continually
- Don't want heart to contract for sustained period of time bc it needs to remain a pump
-
Wave summation
Tension achieved under rapid repeated stimuli is greater than the tension of a single muscle twitch
-
Incomplete tetanus
When periods of stimulation occur but some relaxation occurs between contractions
-
Complete tetanus
Periods of stimulation occur w/no relaxation between stimuli, a sustained contraction results
-
ATP
- Immediate source for muscle contraction
- Only enough on hand for 5-6 seconds of contraction
-
Creatine Phosphate
- High-energy molecule which can be used to produce more ATP quickly during prolonged exercise
- Released energy is used to convert ADP to ATP so the muscle can use it as an energy source for contraction
- Provides energy for about 15 secs
-
Glucose
- Muscles use this for energy during prolonged exercise
- Stored as glycogen and is converted back to glucose which is then further broken down by glycolysis into: 2 molecules of pyruvic acid and 2 molecules of ATP
-
Glycolysis
- Anaerobic process; does not utilize oxygen
- Quick, little energy, therefore must switch to oxidative phosphorylation i.e Krebs
-
Krebs cycle
- Further breaks down sugar into much more energy
- Pyruvic acid enters the mitochondria, where it is completely broken down into CO2 and water
- Requires oxygen; aerobic respiration/cellular respiration/oxidative phosphorylation
- 2 molecules of pyruvic acid generate 36 ATP
-
Oxygen deficiency
If oxidative phosphorylation cannot take place after glycolysis, the pyruvic acid is converted to lactic acid-- some of which will diffuse out of muscle fiber into the blood stream
-
Lactic acid diffusion
- Typically takes 30 mins after exercise ends
- Contributes to muscle fatigue and pain
-
Oxygen Debt
- The amount of oxygen needed to be taken into the system after exercise to metabolize the lactic acid, restore the creatine phosphate supply and re-oxygenate the myoglobin in the muscle tissue
- When you start to breathe heavy, you have surpassed myoglobin stores
-
Lactic acid build-up triggers
- Respiratory centers of the brain to begin rapid deep breathing to replace oxygen and rid the muscle tissue of lactic acid
- More exercise= increased aerobic respiration= decrease in oxygen debt
-
Muscle fatigue
- The inability of the muscle to maintain its strength of contraction after prolonged use due to lack of energy
- Happens when a muscle is repeatedly stimulated
- May be a response to lowering of the pH from lactic acid buildup or low stores of myoglobin
-
Myoglobin
Oxygen-binding protein that increases the rate of oxygen diffusion into a muscle fiber and provides a small store of oxygen within the fiber
-
Fast skeletal muscles
- Type II fibers that contain the high ATP-ase activity or fibers that can split ATP at a faster rate of cross bridge cycling and therefore 4x faster shortening velocities
- Doesn't burn oxygen to create energy
-
Fast oxidative skeletal muscles
- Have numerous mitochondria and have the high capacity for oxidative phosphorylation (make lots of ATP)
- Typically have more blood flow and contain large amounts of myoglobin to provide oxygen for the process
- "pink" muscle
-
Fast glycolytic muscle
- Have fewer mitochondria but more glycogen stores
- Have less blood vessels supplying them, and less myoglobin
- Aka white muscle fibers
-
Slow muscle
- Fibers containing myosin with lower ATPase activity are called these
- Type I fibers
- 4x slower than fast muscles but have same force production
- Typically have high oxidative capacity; efficient at using oxygen
- Best for long distance w/ great myoglobin stores
- Slow glycolytic not found
-
Cerebral Motor Cortex
Cortical areas controlling motor functions lie in the posterior part of frontal lobes
-
Sensorimotor cortex
- All the areas of the cerebral cortex that control muscle movement
- Include:
- Primary motor cortex
- Premotor cortex
- Brocas areas
-
Primary motor cortex
- Large neurons called pyramidal cells allow us to consciously control muscle movements
- Long axons form massive tracts called pyramidal or corticospinal tracts
- Located on precentral gyri
- Control is contralateral; right controls left and vise versa
-
Premotor Cortex
- Anterior to primary motor cortex
- Controls learned motor skills or a repetitive nature (musical instruments, typing)
- Supplies 15% of the pyramidal tract fibers
- Sends coordinated impulses to the primary motor area
-
Brocas areas
- Anterior/inferior to premotor
- Located only in the left hemisphere
- Responsible for motor coordination of speech (articulation)
- Muscles to tongue, throat, and lips
-
Basal nuclei
- Gray matter deep within the cerebral white matter
- Receives inputs from the entire cerebral cortex and projects to premotor cortex, so influences movement directed by primary motor cortex
- Plays a role in sorting, stopping and monitoring movement, regulates intensity of movement and inhibits unnecessary movement
- Impairment results in poor posture and muscle tone, tremors at rest, and abnormal slowness of movement (bradykinesia)
-
Parkinson's Disease
- Characterized by resting tremor
- Slowed/absent movement (hypokinesia)
- Rigidity of the extremities and neck
- Reduced facial expressiveness
- Caused by the loss of dopamine in the substantia nigra as a part of the basal nuclei
-
How to treat Parkinson's
L-Dopa
-
Cerebellum
- Processes inputs received from cerebral motor cortex, brain stem nuclei
- Sensory receptors from muscle fibers, eyes, and vestibular apparatus (equilibrium) and proprioreceptors
- Modifies movement to provide precise timing and pattern for smooth coordinated movement
- Subconscious control
-
Cerebellar disease
- Intention tremor
- Tremors that are absent at rest, appears when person attempts voluntary movement
- Esp pronounced as movement reaches final destination
- People cannot start/stop movement well; lack of corrdination
- Have poor posture and unstable gait; cannot stand on one foot w/ eyes closed
-
Signs of cerebellar damage
- Vertigo
- Ataxia
- Nystagmus
- Intentional tremor
- Slurred speech
- Hypotonia
- Exaggerated broad based gait
- Disdiadochokinesia: inability to perform rapid repeating alternating movement
-
Descending pathways
- Descending tracts that deliver efferent impulses from the brain to spinal cord
- 2 types: corticospinal or pyramidal tracts and the brainstem pathways
-
Pyramidal tracts
- Major motor pathways concerned with voluntary movement (especiallly precise or skilled movement
- Axons descend without synapsing from primary motor cortex all the way to spinal cord
- Crossover in the medulla oblongata for contralateral innervation
-
Brainstem pathways or extrapyramidal nuclei
- Descending pathways that don't pass through the pyramids
- Originate in the brain stem
- Concerned w/postural control, balance and walking
- Most do not cross to other side
-
-
-
CN V
- Chewing or mastication
- Cornea movement
-
-
CN VII
- Facial
- Facial expression
- Cornea movement
-
-
CN X
- Vagus
- Heart rate, breathing, digestive
-
CN XI
- Accessory
- Movement of head and neck
-
CN XII
- Hypoglossal
- Chewing, swallowing, speech
-
Cranial nerves only sensory
- I olfactory
- II optic
- VIII vestibulocochlear
|
|