Exam 2 Flashcards
aside from cAMP, what are some other common second messengers in G-protein coupled receptor transduction pathways?
IP3, DAG, Ca2+
______ is the most powerful second messenger that we know of
Calcium
In cells that use Ca2+ as a second messenger instead of cAMP, G-protein coupled receptor activation leads to activation of the effector molecule _____
PLC (Phospholipase C).
PLC catalyzes the hydrolysis of ____ , which is found in phospholipid tails, into ___ and ___.
- PIP2 (Phosphatidylinositol bisphosphate)
- IP3
- DAG
___________ and _________ are both lipid signaling molecules.
- IP3 (inositol triphosphate)
- DAG (diacylglycerol)
o DAG activates ________, which phosphorylates transcription factors and alters gene expression.
-Protein Kinase C
IP3 binds its receptor on the __________, which acts as a ____ channel and releases stored Ca2+ into the cytosol. This Ca2+ release, through a poorly-understood mechanism, opens a class of plasma membrane ion channels called ________________ channels and allows external Ca2+ to enter the cell and replenish depleted Ca2+ stores in the endoplasmic reticulum.
- endoplasmic reticulum
- Ca2+
- Transient Receptor Potential
- Afferent division: Carries information ____ the CNS
- Efferent division: Carries information _____ the CNS
- TO
- away from
Efferent division: Carries information away from the CNS to _____________
effector organs.
Effector organs-
o Muscles and glands that carry out orders to bring about the desired effect
The Efferent division is subdivided into what two divisions?
somatic and autonomic
the somatic nervous system consists of:
fibers of motor neurons that supply skeletal muscles
The autonomic nervous system consists of:
fibers that innervate smooth muscle, cardiac muscle, and glands
the autonomic nervous system is subdivided into what two divisions?
- Sympathetic nervous system
* Parasympathetic nervous system
at the peripheral ending of an afferent neuron there is a _______ that generates _____ in response to stimuli
- Sensory Receptor
- Action Potentials
interneurons are found entirely within the ____. They lie between _________
- CNS
- afferent and efferent neurons
interneurons are responsible for: (2 things)
- Integrating afferent information and formulating an efferent response
- higher mental functions associated with the “mind”
neuroglia are also called:
glial cells or non-neuronal cells
Unlike neurons, neuroglia do not __________, but they do communicate with neurons and among themselves via _________
- initiate or conduct nerve impulses
- chemical signals
Neuroglia serve as ___________ of CNS:
Connective Tissue
neuroglia support neurons in 3 ways:
• Physically, metabolically, and functionally
4 major types of glial cells:
- Astrocytes
- Oligodendrocytes
- Microglia
- Ependymal cells
what is the most abundant of all glial cells?
astrocytes
which glial cell is the main glue of the CNS, holding the neurons together?
astrocytes
Astrocytes are named for their _____ appearance
starlike
Which cells guide neurons during fetal brain development?
astrocytes
_________ induce capillaries of brain to undergo changes that aid in establishment of blood-brain barrier
astrocytes
Important in repair of brain injuries and in neural scar formation:
astrocytes
• They are like the road signs and pavement for neurons:
astrocytes
Play role in neurotransmitter activity:
•Take up and degrade Glutamate and GABA
astrocytes
Take up excess K+ from brain ECF:
• Helps maintain optimal ion conditions for neural excitability
astrocytes
• Along with other glial cells- enhance synapse formation and modify synaptic transmission
astrocytes
• Form insulative myelin sheaths around axons in CNS
oligodendrocytes
• Immune defense cells of the CNS. Made from bone marrow. Remove foreign invaders or excess tissue by phagocytosis.
Microglia
• Release destructive chemicals that are suspected to play a role in Alzheimer’s disease, multiple sclerosis, and dementia
microglia
• In resting state release low levels of growth factors that help neurons and other glial cells survive and thrive
microglia
helps neurons and glial cells survive:
Nerve Growth Factor
• Line internal, fluid-filled cavities in the brain
ependymal cells
• Ciliated cells help form and circulate cerebrospinal fluid
ependymal cells
Unlike neurons, glial cells do not lose ability to ______, so most brain tumors consist of glia
divide
Brain tumors are generally a result of ______________, or ____________________
- cells that have metastasized and migrate to the brain from other regions
- meningiomas, which originate from the meninges, the protective covering of CNS cells.
_______ (skull) encases brain
Cranium
_________ surrounds spinal cord
Vertebral Column
the brain is wrapped by 3 protective and nourishing membranes- meninges:
- Dura mater
- Arachnoid mater
- Pia mater
Pia mater
fragile, inner-most vascularized layer
Arachnoid mater
web-like covering
Dura mater
tough inelastic covering
major function of CSF?
It also helps with the ________________
- shock absorbing fluid to prevent brain from colliding with skull
- Exchange of materials between neural cells and interstitial fluid surrounding brain
CSF is formed primarily by:
choroid plexuses
choroid plexuses-
• Richly vascularized masses of pia matter tissue that dip into pockets formed by ependymal cells
BBB prevents certain circulating hormones that could also act as ____________ from reaching brain
neurotransmitters
how do we get around BBB preventing drugs from getting to brain? 2 ways
- Intracranial drug delivery
* Use existing transporters
how many neurons are in the brain?
100 billion
CNS allows you to do 5 things primarily:
- Subconsciously regulate your internal environment by neural means
- Experience emotions
- Voluntarily control your movements
- Be consciously aware of your own body and your surroundings
- Engage in other higher cognitive processes such as thought and memory
who said “The brain is the organ with which we think… we think”
Ambrose Bierce
the brain weighs _______
3-3.5 lbs
the brain receives __% of the total blood flow to the body per minute
15
o Scientists have demonstrated ________ (the formation of new brain cells from stem cells) in adult brains within the hippocampus.
neurogenesis
The Brain Stem is continuous with ______
spinal cord
The Brain Stem controls many life-sustaining processes, such as ________ (3 things) because they are performed involuntarily.
respiration, circulation, and digestion (vegetative functions),
proper________ function is all that is necessary to ensure survival at a basal level.
brain stem
The brain stem is concerned with maintaining proper ____________ (2 things)
position of the body in space and subconscious coordination of motor activity (movement)
the brain stem consists of 3 things:
- Midbrain
- Pons
- Medulla
Neurons that use dopamine are highly concentrated in the ________.
midbrain
involved in motor control. Damaged in patients with Parkinson’s disease.
Nigrostriatal dopamine system
involved in emotional reward. Overly-active during drug addiction.
Mesolimbic dopamine system
Nigrostriatal Dopamine System
o Neurons from the__________ of the brain send dopaminergic neurons to the __________
• Important step in the control and initiation of __________
• _________ disease is caused by degeneration of these neurons.
• Patients are treated with ___________ (2 things)
- substantia nigra
- corpus striatum.
- movements
- Parkinson
- L-dopa and MAOIs (monoamine oxidase inhibitors)
Mesolimbic Dopamine System
o Regions of the _______ send dopaminergic neurons to regions of the _______
• Involved in _________ and associated with ________
• ___________ is associated with too much dopamine in this system
• Drugs that treat schizophrenia are _____________.
- midbrain
- forebrain.
- emotional reward systems
- addictions
- Schizophrenia
- dopamine antagonists
Cerebellum
- ________ region of the brain
- Attached at ________ portion of brain stem
- Important role in ______________ by sending input to the motor areas of cortex
- Maintains proper ___________
- __________ coordination of motor activity (movement)
- Plays key role in learning ____________
- Subcortical
- top rear
- planning, initiating, and timing movements
- position of the body in space
- Subconscious
- skilled motor tasks
The Diencephalon houses what 2 brain components?
hypothalamus and thalamus
Hypothalamus
- Controls many homeostatic functions important in maintaining stability of internal environment: (5 things)
- Serves as _________ coordinating center
- Affects all _________ muscle and ____________ glands
- Plays role in _____ and _____ patterns
- Most involved in regulating __________
- body temperature, thirst, urine output, food intake, anterior pituitary hormone secretion
- ANS (Autonomic Nervous System)
- smooth and cardiac
- sweat, salivary and other exocrine
- emotional and behavioral
- internal environment
Thalamus
- Performs some primitive __________
- Serves as a “relay station” for _________
- Screens out __________ and routes ____________ to appropriate areas
- Helps to direct attention to ___________
- sensory processing
- preliminary processing of sensory input
- insignificant signals
- important sensory impulses
- stimuli of interest
Cerebrum
- Highly _______
- Makes up about __% of total brain weight (largest portion of brain)
- Divided into 2 halves:
- Outer surface is _______ cerebral cortex
- outer surface caps inner core that houses ________
- Highest, most complex integrating area of the brain
- Plays key role in ______________
- developed
- 80
- Right and Left Cerebral Hemispheres
- highly convoluted
- basal nuclei
- most sophisticated neural functions
Cerebral Cortex
- Thin outer shell of _____ matter that covers each hemisphere of cerebrum
- organized into __ well defined layers
- layers are organized into ______
- each half cortex is divided into what 4 major lobes?
- grey
- 6
- functional vertical columns
- occipital, temporal, parietal, frontal
Parietal lobe:
Receive and process sensory input
Frontal lobe
-Responsible for 3 main functions:
- Voluntary motor activity
- Speaking ability
- Elaboration of thought
Primary Motor Cortex
- Located in _____ lobe
- Confers voluntary control over ___________ -Primarily controls muscles on ______ side of the body
- frontal
- movement produced by skeletal muscles
- the opposite
The “Pain Matrix” consists of _______________. Chronic pain conditions such as fibromyalgia and neuropathy are thought to be due to ______________
- 9 different subnuclei in all different areas of the brain.
- overactivity of neurons in these areas of the brian.
name 2 chronic pain conditions.
fibromyalgia and neuropathy
Pain is a conscious phenomenon. Neurotransmitters such as _____ and ____, as well as neuromodulators such as ______ are the physical manifestation of pain. Neurons in the pain matrix use these chemical messengers to increase our perception of pain as a means of self-preservation
- glutamate
- GABA
- substance P
Narcotic pain relievers are usually__________ for receptors for glutamate, GABA, and substance P on these neurons in the pain matrix.
competitive antagonists
chronic use of narcotic pain medications like ______ and _______ will inevitably lead to ______.
- ketamine
- morphine
- addiction
Researchers have recently begun examining the connection between our perception of pain and the _______________
level of brain activity we devote to dealing with pain.
giving pain “attention” means giving pain “meaning”. Emotional significance leads to _________, which makes the perception of pain more intense.
neuromodulation
The anxiety and fear that builds up when pain is expected causes neurons in the “__________” in the ________ within pain matrix to become overactive, and it changes the way these cells talk to each other.
- fear center
- amygdala
Two key experiments have provided evidence to support phenomenon between how much we think of pain and our perception of it:
- Virtual reality for military burn victims
- Shock experimentation for prison inmates
Virtual reality for military experiment, quickly describe:
virtual reality lessened their percep. of pain from a 10 to a 5, or they didn’t even know they were being scrubbed
Shock experiments for inmates, quickly describe:
same shock, but each successive time the pain activity measured was more severe because they anticipated the shock
o Most of the knowledge of how the brain controls language has come from studying people with speech problems called ______.
aphasias
Two forebrain areas are identified as important in language:
- Broca’s area
* Wernicke’s area
Broca’s Area
-Located in:
-Broca’s aphasia involves ____________ speech. There is no impairment in ___________.
Controls ______ aspects of speech
- left inferior frontal gyrus
- slow, poorly articulated
- understanding
- motor
Broca’s area
Interestingly, other actions of the tongue, lips, and larynx are not affected; only the __________ is affected.
production of speech
Wernicke’s Area
- Located in:
- Wernicke’s aphasia involves _________________
- Controls _________ of words.
- left superior temporal gyrus
- production of rapid speech with no meaning, called “word salad.” Language (spoken and written) comprehension is destroyed.
- understanding
To speak, word comprehension originates in _____ area and is sent to ____ area.
Wernicke’s
-Broca’s
Functions of Cerebral cortex:
- What area plays a preparatory role in programming complex sequences of movement?
- what area is important in orienting the body and arms toward a specific target?
- what area lies posterior to primary somatosensory cortex?
- supplemental motor area
- premotor cortex
- posterior parietal cortex
Damage to the posterior parietal cortex or primary somatosensory cortex prevents one from ________________. Check that this slide is correct
processing complex sensory information to accomplish purposeful movement.
Damage to what 3 areas will cause motor movement difficulty?
supplemental motor areas, premotor cortex, or posterior parietal cortex
mirror neurons are found where?
frontal and parietal lobes.
mirror neurons are connected to ________ centers in the brain.
emotion
Mirror neurons are activated when:
we observe the expressions of others and mimic them ourselves.
mirror neurons may be involved in the ability to __________
learn social skills and language
mirror neurons allow for _____
empathy
Mirror neurons have been implicated in _____
autism
Individuals with autism have mirror neurons that don’t respond to ____________, but only to ___________
- emotions or actions of others
- their own actions
Left Cerebral hemisphere:
- Excels in:
- Tends to process information in ________ way
- logical, analytical, sequential, and verbal tasks (Math, language forms, philosophy)
- fine-detail
Right cerebral hemisphere
-Excels in _______ skills
Views the world in a ________ way
- non language (Spatial perception and artistic and musical talents)
- big-picture, holistic
Normally, the 2 hemispheres _____each other
-complement
Left cerebral hemisphere dominance associated with “_____”
Right hemispheric skills dominate in “_____”
- thinkers
- creators
Brain area most involved in directly regulating internal environment
Hypothalamus
What 9 things does the hypothalamus participate in or control?
- Controls body temperature
- Controls thirst and urine output
- Controls food intake
- Controls anterior pituitary hormone secretion
- Produces posterior pituitary hormones
- Controls uterine contractions and milk ejection
- Serves as a major ANS coordinating center
- Plays role in emotional and behavioral patterns
- Participates in sleep-wake cycle
o Not a separate structure but a ring of forebrain structures that surround the brain stem
Limbic System
The limbic system includes:
portions of the hypothalamus and other forebrain structures that encircle brain stem
The limbic system is responsible for: (3)
- Emotion
- Basic, inborn behavioral patterns related to survival and perpetuation of the species
- Plays important role in motivation and learning
There are few synaptic connections between ________, which is why it is hard to control your emotions.
the limbic system and the cerebral cortex
Emotions controlled by the limbic system: (5)
- Aggression: areas in the amygdala and hypothalamus
- Fear: amygdala and hypothalamus
- Hunger/satiety: hypothalamus
- Sex drive: the whole system
- Goal-directed behaviors: hypothalamus and other regions
o Memory trace-
Neural change responsible for retention or storage of knowledge
o Short-term memory-
Lasts for seconds to hours
o Long-term memory-
Retained for days to years
Consolidation-
Process of transferring and fixing short-term memory traces into long-term memory states (during sleep?)
Working memory-
Temporarily holds and interrelates various pieces of information relevant to a current mental task
Studies of people with amnesia reveal that areas of the __________ (4) are involved in memory.
temporal lobe, hippocampus, caudate nucleus, and dorsomedial thalamus
The ______ is important in learning fear responses.
amygdala
_________ may be involved in working memory- very short-term memory.
The prefrontal cortex
• Memory consolidation occurs in the _____________ (3)
medial temporal lobe, hippocampus, and amygdala.
______ is needed for optimum memory consolidation
Sleep
_______ memory requires actual structural change
long term
Long-term memory can be classified into:
- Nondeclarative (implicit)
- Declarative (explicit)
-Nondeclarative (implicit):
memory of simple skills, how to do things
-Declarative (explicit):
memory of things that can be verbalized.
Declarative memory is further broken down into:
semantic and episodic
Semantic:
facts: how old are you, where do you live
Episodic:
events: what did you eat for dinner, tell me about this event
People with amnesia have impaired _____ memory
declarative
If the memory has an emotional component, the _____ is involved in memory formation. This is why you only remember the really good or really bad days of your life.
amygdala
Stress impairs memory formation in the _____ and working memory function of the _____
- hippocampus
- prefrontal cortex.
It is thought that cortisol may strengthen _____ memory formation via the amygdala but weaken _________
- emotional
- hippocampal memory formation and memory retrieval.
The amygdala and hippocampus have receptors for _____ hormones
stress
LTP stands for-
long term potentiation
Centers that govern sleep are in ______
brain stem
_______ builds up during day. Inhibits arousal-leads to drowsiness. Injections of it lead to sleep.
Adenosine
Caffeine blocks ______ receptors.
adenosine
Adenosine levels drop during sleep because
ATP is being made.
Function of sleep is unclear: There are some hypotheses
-repair damage from ________
-Long-term structural and chemical adjustments for learning and memory.
• Might be why infants require so much sleep.
toxic free radicals.
In 1950, the avg. person claimed to get ___ hours of sleep. That number is now _____
- 8.5
- 6.5
In a study on healthy 20 yr old males, what was done to them and what was the result.
they were allowed to sleep but an alarm brought them out of REM sleep so that they were getting adequate sleep but none of it was REM. After 2 weeks, all 20 subjects were in a pre-diabetic state, where their cells were becoming resistant to insulin. They all had elevated blood pressure and cholesterol levels, and were at risk for heart disease.
Sleep-wake cycle-
Normal cyclic variation in awareness of surroundings
Sleeping people are not consciously aware of external world
Sleep is an active process consisting of two types of sleep characterized by different ________ and different _____. What are the 2 types?
- EEG patterns
- behaviors
- Slow-wave sleep and paradoxical, or REM sleep
EEG stands for:
Electroencephalogram
EEG is collected by____________
external electrodes on the scalp.
EEG measurement is not due to action potentials, but instead represent the ____________
collective postsynaptic potential activity in the cortex (EPSPs + IPSPs)
EEG uses: (3)
- Diagnosis of medical conditions
- Legal determination of brain dead
- Sleep stage analysis
The largest group of tissues in the body:
muslce
what 2 ways are muscle classified?
striated or unstriated and voluntary or involuntary
_______ is the only unstriated muscle
smooth
______ is the only voluntary muscle
skeletal
Controlled muscle contraction allows 4 things:
- Purposeful movement of the whole body or parts of the body
- Manipulation of external objects
- Propulsion of contents through various hollow internal organs
- Emptying of contents of certain organs to external environment
Muscle consists of a number of muscle fibers lying ______ to one another and held together by _________
- parallel
- connective tissue
- A single skeletal muscle cell is known as a _______
- How many nuclei?
- Large, elongated, and _______ shaped
- Fibers usually extend how far?
- muscle fiber
- Multinucleated
- cylindrically
- entire length of muscle
Contractile elements of skeletal muscle fibers
myofibrils
myofibrils are regular arrangements of __________
thick and thin filaments
thick filaments are made of:
myosin
thin filaments are made of:
actin
• Viewed microscopically myofibril displays alternating dark (the _ bands) and light bands (the _ bands) giving the appearance of striations.
- A
- I
Functional unit of skeletal muscle
sarcomere
Found between 2 _ lines (connects thin filaments of two adjoining sarcomeres)
Z
Regions of Sarcomere
- A band:
- H zone:
- M line:
- I band:
- Made up of thick filaments along with portions of thin filaments that overlap on both ends of thick filaments
- Lighter area within middle of A band where thin filaments do not reach
- Extends vertically down middle of A band within center of H zone
- Consists of remaining portion of thin filaments that do not project into A band
Giant, highly elastic protein
Titin
Largest protein in body:
Titin
Titin extends in both directions from _________ to __________
- M line along length of thick filament
- Z lines at opposite ends of sarcomere
Titin has 2 important roles:
- Along with M-line proteins helps stabilize position of thick filaments in relation to thin filaments
- Greatly augments muscle’s elasticity by acting like a spring
-myosin consists of ________ subunits shaped like a ________.
-Tail ends are interwined around each other,
globular heads project out at one end
- 2 identical
- golf club
myosin tails are oriented toward ___________ and globular heads protrude _______ at regular intervals.
- center of filament
- outward
myosin heads from _________ between thick and thin filaments (actin)
cross bridges
A cross bridge has 2 important sites critical to contractile process:
o An actin-binding site
o A myosin ATPase (ATP-splitting) site
Actin is _____ in shape
spherical
thin filament also has 2 other proteins besides actin:
- Tropomyosin
* Troponin
Each actin molecule has special binding site for ____________. Binding results in _____________
- attachment with myosin cross bridge
- contraction of muscle fiber
Actin and myosin are often called contractile proteins, however ____________.
-Actin and Myosin are not unique to muscle cells, but are more _________ and _________ in muscle cells
- neither actually contracts.
- abundant and more highly organized
Tropomyosin and Troponin are often called ______ proteins
regulatory
Thread-like molecules that lie end to end alongside groove of actin spiral
Tropomyosin
when lying within the groove of the actin spiral, tropomyosin does what?
covers actin sites blocking interaction that leads to muscle contraction
Troponin is made of _ polypeptide units
- One binds to ______
- One binds to ______
- One can bind with _____
- It is a ____ sensitive molecule
- 3
- tropomyosin
- actin
- Ca2+
- Ca2+
When not bound to Ca2+, troponin does what?
When Ca2+ binds troponin, what happens?
- stabilizes tropomyosin in blocking position over actin’s cross-bridge binding sites
- tropomyosin moves away from blocking position, allowing actin and myosin to bind and interact at cross-bridges. muscle contraction results
• Cross-bridge interaction between actin and myosin brings about muscle contraction by means of the ________ mechanism.
sliding filament
Muslce Relaxation:
- Depends on reuptake of ____ into _______
- Acetylcholinesterase breaks down Ach at __________
- Muscle fiber action potential stops
- When local action potential is no longer present, Ca2+ moves where?
- Ca2+
- sarcoplasmic reticulum (SR)
- neuromuscular junction
- back into sarcoplasmic reticulum
Sarcoplasmic Reticulum:
Modified ___________
-Consists of fine network of _____________
-Segments are wrapped around _____________
- endoplasmic reticulum
- interconnected compartments that surround each myofibril
- each A band and each I band
T tubules are also called:
transverse tubules
Transverse Tubules:
- Run perpendicularly from _____________ into _____________
- Since membrane is continuous with surface membrane- action potential on surface membrane also _____________
- Spread of action potential down a T tubule triggers____________________
- surface of muscle cell membrane
- central portions of the muscle fiber
- spreads down into T-tubule
- release of Ca2+ from sarcoplasmic reticulum into cytosol
The EEG of Paradoxical sleep looks like:
The EEG of Slow wave sleep looks like:
- an awake person’s EEG
- Large, defined waves/slow waves
