Physiology 2

• A state of changed consciousness or partial consciousness which can be aroused by stimulation
• Defined by 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

• 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
• 

• 8-13 Hz
• Decreased amplitude, slow waves, calm, relaxed, awake, eyes closed

• 14-25 Hz
• Higher frequency, lower amplitude, a bit irregular, awake, alert, concentrating hard on something
• Aka 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

• 4-8 Hz
• Early stage and REM sleep
• Abnormal in awake adults
• Higher amplitude, low frequency waves
• Seen in narcolepsy

• <4 Hz
• Increased amplitude, further decreased frequency
• Ex: deep sleep (dreamless) and anesthesia

• Beta
• Alpha
• Theta
• Delta

Sleep produces depressed cortical activity, but brain stem function continues (respiration, heart rate, blood pressure)

• Brain stem white matter, keeps you alert
• May regulate sleep; causing shifts in states of consciousness

• 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

Starts naturally around 9:00pm and ends round 7:30am

• Has a restorative function
• Gives the brain the opportunity to mentally sort through the days events

• Daily requirements of sleep decline with age:
• Infants-16 hours
• Adults- 7 hours
• Elderly- <7 hours

>60 years

• 50% in infants
• 25% in adults

• 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

• 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)

• 1-> 2-> 3-> 2-> 1-> REM 
• Takes 90-120 mins

• 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

• EEG patter becomes more irregular, arousal is more difficult
• More stable sleep begin

Transition to theta waves

• 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

• 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

• 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

• 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

Acquisition and storage of information as a consequence of experience

• 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

Neural processes that change an experience into a memory of that experience- the physiologic events that lead to memory formation

• 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)

• Declarative memory-- hippocampus, amygdale and diencephalon
• Procedural memory-- sensory-motor cortex, the basal nuclei and the cerebellum

• Retention and recall of conscious experiences that there be put into words (declared)
• Names, facts, and events
• Fact 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

• Explicit and declarative
• Length of minutes to years
• More situational like remembering what you had for breakfast and what vacation you took

• Explicit, declarative
• Length of minutes to years
• Knowing facts such as your mother's maiden name

• Limitless capacity
• Scores of phone numbers
• The ability to store and retrieve decreases with age

• 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

• 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)

• Hippocampus- limbic system
• Amygdala- limbic system
• Thalamus- diencephalon
• Hypothalamus- diencephalon
• Association areas (areas that surround and are associated with your senses)

Oversees learning circuits and remembering spatial relationships

• 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

• Damage to either hippocampus or amygdala 
• Results in only slight memory loss
• Destruction to both results in widespread 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

• Loss of memories formed in the distant past but can make new memories
• Ability to consolidate is there
• Amygdala may be damaged

• 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)

• 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

• 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

• 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

• 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

• 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

• 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

• The person may not be able to understand what is meant by a text 
• Differentiate between inflection tone i.e happy vs sad speech

• 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

• 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

Refers to a number of muscle fibers bound together by connective tissue

Wraps each muscle fiber

Wraps each fascile (several muscle fibers bundled together

Wraps entire muscle

• Connects muscle to bone
• Epimysium extending beyone muscle to interweave into periosteum

Attachment on the moveable bone; pull insertion closer to the origin

Attachment on the immoveable bone

Bone to bone, extensions of the connective tissue coverings found in muscle

• Involuntary in hollow organs and vessels
• Narrow cylindrical fibers
• Nonstriated
• Uninucleate

• Involuntary found in the heart
• Striated
• Branched
• Generally uninucleate fibers

• Voluntary muscle that is attached to the skeleton
• Very striated
• Tubular
• Multi nucleated fibers

• 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

• Cytoplasm of the muscle cell
• Large amounts of 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

• Modified endoplasmic reticulum
• Regulates intracellular levels of Ca
• Stores and releases Ca²⁺
• Wraps each myofibril like a shirt sleeve

• 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

• Modified organelle of a muscle cell
• Contractile elements in muscle and run in parallel fashion
• Makes up about 80% of cell volume

• A chain of these contractile units make up each myofibril
• Arrangement of dark and light bands within this is responsible for striations

• A bands
• Each A band has a lighter midsection called H zone (only in relaxed state)

• I bands
• Each I band has a darker midsection called Z line
• Sarcomeres run Z line to Z line

• Proteins that cause the banding pattern; even smaller structures within sarcomeres
• Thick and thin myofilaments are made of Actin and Myosin

• 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
• 

• Composed primarily of Actin proteins-- looks like two strands of pearls twisted together
• Tropomyosin and troponin (regulatory proteins) are present on this

Protein strands on actin that block active sites on actin so myosin cannot bind to actin in a relaxed muscle

Ca binds, changes structure, and causes tropomyosin to slide and expose myosin binding sites on tropomyosin

• 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

• 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

• 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

Trough-like part of the sarcolemma that helps to form neuromuscular junction, is highly folded to increase surface area which allows for more receptors

• 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)

• 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

• Latent period
• Contraction
• Relaxation
• Refractory

• Brief period between stimulus applied and contraction
• Ca+ is released from the SR and myosin head begins during latent period

• Muscle is contracting 
• Time depends on slow vs fast twitch

Muscle fibers are returning to their uncontracted states, repolarizing

• 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= short
• Cardiac= long

• 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

Tension achieved under rapid repeated stimuli is greater than the tension of a single muscle twitch

When periods of stimulation occur but some relaxation occurs between contractions

Periods of stimulation occur w/no relaxation between stimuli, a sustained contraction results

• Immediate source for muscle contraction
• Only enough on hand for 5-6 seconds of contraction

• 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

• 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

• Anaerobic process; does not utilize oxygen
• Quick, little energy, therefore must switch to oxidative phosphorylation i.e Krebs

• 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

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

• Typically takes 30 mins after exercise ends
• Contributes to muscle fatigue and pain

• 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

• 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

• 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

Oxygen-binding protein that increases the rate of oxygen diffusion into a muscle fiber and provides a small store of oxygen within the fiber

• 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

• 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

• Have fewer mitochondria but more glycogen stores
• Have less blood vessels supplying them, and less myoglobin 
• Aka white muscle fibers

• 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

Cortical areas controlling motor functions lie in the posterior part of frontal lobes

• All the areas of the cerebral cortex that control muscle movement
• Include: 
• Primary motor cortex
• Premotor cortex
• Brocas areas

• 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

• 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

• Anterior/inferior to premotor
• Located only in the left hemisphere
• Responsible for motor coordination of speech (articulation)
• Muscles to tongue, throat, and lips

• 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)

• 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

L-Dopa

• 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

• 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

• Vertigo
• Ataxia
• Nystagmus
• Intentional tremor
• Slurred speech
• Hypotonia
• Exaggerated broad based gait
• Disdiadochokinesia: inability to perform rapid repeating alternating movement

• Descending tracts that deliver efferent impulses from the brain to spinal cord
• 2 types: corticospinal or pyramidal tracts and the brainstem pathways

• 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

• 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

• Oculomotor
• Eye movement

• Trochlear
• Eye movement

• Chewing or mastication
• Cornea movement

• Abducens
• Eye movement

• Facial 
• Facial expression
• Cornea movement

• Glossopharyngeal
• Tongue

• Vagus
• Heart rate, breathing, digestive

• Accessory 
• Movement of head and neck

• Hypoglossal
• Chewing, swallowing, speech

• I olfactory
• II optic
• VIII vestibulocochlear