master one Flashcards
DNA methylation
- Methyl group binds to a segment of DNA
- Can either decrease or increase gene expression (transcription)
What is physiological (biological) psychology?
The scientific study of the biology of behavior
Belief that the brain and the mind are the same thing
Monism
Dualism
The mind is separate from the physical brain
Monist
If you believe that there is no mind without a brain, you are a:
Confounding variable
- An outside influence that changes the effect of a dependent and independent variable
- Male sexual fatigue in Coolidge experiment
What is the Coolidge effect?
Renewed interest when introduced to a new and receptive sexual partner, even after cessation with a previous but still available partner
Genotype
A set of genes that an organism carries and is born with
Phenotype
All of an organism’s observable characteristics, which are influenced by both its genotype and by the environment
Epigenetics
Study of mechanisms of inheritance other than the genetic code
How do genes yield traits (how does genotype become phenotype)? That is, what are the biological processes that lead to synthesis of cell proteins such as receptors and ion channels?
DNA → (Transcription) → RNA →(Translation) → Protein → Trait
What gene in the amygdala contributes to neuroticism?
The gene that encodes GABA receptors
If the gene that encodes GABA receptors is highly expressed in Person A, but not Person B, who is more neurotic?
Person B
If Person B’s amygdala neurons make some GABA receptors, but Person A’s makes more which results in lower neural firing for Person A , who is more neurotic?
Person B
What type of individual would result from neurons making some GABA receptors
- Risk adverse
- FacMan
What type of individual would result from neurons making more GABA receptors which results in lower neural firing
- Bold & fearless
- Climbing wall
What are environmental influences that could contribute to someone having high or low levels of neuroticism?
Traumatic experiences, such as having a bad fall off of the climbing wall, could lower someone’s GABA receptor amount
A genetic mechanism by which two people could differ in their adult levels of anxiety/fear (neuroticism) is:
- They could have inherited genes from their biological parents that predispose them to greater/lesser anxiety/fear
- They could have had different experiences in life that caused different epigenetic changes in their amygdala gene expression
One specific molecular mechanism that could underlie high anxiety in H.B. vs. low anxiety in R.T. is:
H.B.’s gene that encodes for the GABA receptor protein in her amygdala is turned off most of the time, so her amygdala neurons fire a lot, whereas R.T.’s gene that encodes for the GABA receptor protein in her amygdala is turned on most of the time, so that her amygdala neurons fire at a low rate most of the time
Two mechanisms at the DNA level that can result in increased or decreased gene expression (i.e., that can turn genes on or off) after birth
- DNA Methylation
- Histone remodeling
DNA demethylation
- If this occurs, transcription and translation go up
- Increased gene expression
Histone remodeling
- The core around which RNA wraps changes shape –> influences the shape of adjacent DNA
- Increase or decrease in gene expression
What happened to the performance of “maze-dull” vs. “maze-bright” when they are raised by parents who perform differently on tasks?
It didn’t work
What happened when a “maze-dull” rat was placed in an enriched environment?
The rat performed as well as the “maze-bright” rat
What happened when an already “maze-bright” rat was placed in an enriched environment?
No impact
Selective breeding of “maze-bright” and “maze-dull” rats demonstrates what about nature (genes at birth) vs. nurture (genes in adulthood)?
Genetic background that predisposes to “maze-dullness” can be largely overcome by enriching experiences after birth
What is the genetic basis of PKU (phenylketonuria)?
- Genetic disorder inherited from an individual’s parents
- Due to mutations in the PAH gene, which results in low levels of the enzyme phenylalanine hydroxylase. This results in the buildup of dietary phenylalanine to potentially toxic levels
What can PKU (phenylketonuria) impact?
Intellectual problems/abnormal brain development
How can environmental (dietary) adjustment compensate for this gene abnormality?
Providing the kids with phenyl-free foods can prevent kids from suffering from the full blown disorder
How does PKU (phenylketonuria) work?
If the gene that codes for enzyme that converts phe to tyr is non-functional → body cannot synthesize DA (from tyr) → abnormal brain development
For a long time, heritability estimates for various traits such as intelligence were misleading, because they were determined from:
A relatively select (non-diverse) sample of identical twins raised apart vs. together
How can studies of monozygotic (identical) twins be used to help us better understand how environment influences traits/disease as we age?
Epigenetic differences as they age
How to test epigenetic studies of monozygotic (identical) twins
Periodic DNA sampling to screen for methylations and histone modifications
Should monozygotic twins be referred to as identical twins?
To be precise, not exactly - as they grow, each twin’s experiences change their epigenetic profiles
What are the two basic divisions of the nervous system?
- Central nervous system (CNS)
- Peripheral nervous system (PNS)
Where is the central nervous system located?
- Brain
- Spinal cord
What does the central nervous system do?
Controls most functions of the body and mind
What are the two divisions of the peripheral nervous system?
- Somatic nervous system
- Autonomic nervous system
What does the somatic aspect of the peripheral nervous system control?
- Controls voluntary muscles
- Conveys sensory information to CNS
- Interacts with the external environment
What does the afferent nerves of the somatic aspect of the peripheral nervous system do?
- Carry sensory signals from the skin, skeletal muscles, joints, eyes, ears, etc., to the CNS
- Going towards the CNS; arrive
What does the efferent nerves of the somatic aspect of the peripheral nervous system do?
- Carry motor signals from the CNS to the skeletal muscles
- Going away from the CNS; exit
What does the autonomic aspect of the peripheral nervous system control?
- Controls involuntary muscles
- Fight or flight (sympathetic)
- Rest and digest (parasympathetic)
What is an example of an autonomic aspect of the peripheral nervous system function?
Regulating the body’s internal environment
What does the efferent nerves of the autonomic aspect of the peripheral nervous system do?
- Carry motor signals from the CNS to internal organs
- Two types: Sympathetic/parasympathetic
What does the sympathetic efferent nerves of the autonomic aspect of the peripheral nervous system do?
- Fight or flight
- Energy expanding
- Fires less since you aren’t in a constant state of fear/nervousness
What does the parasympathetic efferent nerves of the autonomic aspect of the peripheral nervous system do?
- Rest and digest
- Energy conserving
- Fires more since you aren’t in a constant state of fear/nervousness
What does the afferent nerves of the autonomic aspect of the peripheral nervous system do?
Carry sensory signals from internal organs to the CNS
Which nervous system is more protected than the other?
Central nervous system
What makes the CNS better protected than the PNS?
- Mechanical protection: Skull and meninges (dura mater, arachnoid, pia mater layers), vertebrae, cerebrospinal fluid (buffer/shock absorber)
- Immunological protection: Blood-brain barrier
Which nervous system can regenerate while the other cannot?
The peripheral nervous system can
How does the PNS regenerate itself?
- Schwann cells form lines and reconnect
- Axons regrow as long as the soma is intact
What is the blood brain barrier (BBB), physically?
A highly selective permeable border made of tightly packed cells
What purpose does the blood brain barrier (BBB) serve?
Protects the brain from circulating pathogens
Dorsal (posterior)
Toward or at the back of the body
Ventral (anterior)
Toward or at the front of the body
Lateral
Away from the midline of the body
Medial
Toward or at the midline of the body
Caudal (inferior)
Away from the head or toward the lower part of a structure or the body (below)
Rostral
Towards the nose/beak
Major parts of a neuron
- Cell membrane
- Cell body
- Dendrites
- Axon hillock
- Axon
- Myelin
- Nodes of Ranvier
- Buttons
- Synapses
Cell membrane
The semipermeable membrane that encloses the neuron
Cell body
The metabolic center of the neuron; also called the soma
Dendrites
The short processes emanating from the cell body, which receive most of the synaptic contacts from other neurons
Axon hillock
The cone-shaped region at the junction between the axon and the cell body
Axon
The long, narrow process that projects from the cell body
Myelin
The fatty insulation around many axons
Nodes of Ranvier
The gaps between sections of myelin
Buttons
The button-like endings of the axon branches, which release chemicals into synapses
Synapses
The gaps between adjacent neurons across which chemical signals are transmitted
What are the major types of proteins that are embedded in a neuron’s lipid bilayer membrane?
- Ion channels
- Receptors
- Transporters
What is the role of an ion channel that is embedded in a neuron’s lipid bilayer membrane?
Regulate cation + / cation - flow in/out of cell
What is the role of a receptor that is embedded in a neuron’s lipid bilayer membrane?
- Neurotransmitters bind to them
- Signal excitation (+, increase firing)
- Signal inhibition (-, decrease firing)
What is the role of transporters that are embedded in a neuron’s lipid bilayer membrane?
- Actively move important molecules in/out of the cell
- Ex. Na+ / K+ transporter
Major cations involved with learning/memory and neurotransmitter release
- Na+
- Ca+
- K+
- Mg+
Major anion involved with learning/memory and neurotransmitter release
Cl-
What are the 3 glial cells in the CNS
- Oligodendrocytes
- Microglia
- Astrocytes
Oligodendrocytes
- Glial cell in the CNS
- Produce myelin sheath
Microglia
- Glial cell in the CNS
- Respond to injury/disease
- Clean up: Trigger inflammation, regulate synapse formation and elimination
Astrocytes
- Glial cell in the CNS
- Contribute to the blood brain barrier, regulate blood flow
What glial cell is in the PNS
Schwann cells
Schwann cells
- Glial cell in PNS
- Produces the myelin sheath and results in direct axonal regrowth after injury
What are the 3 major divisions of the brain?
- Hindbrain
- Midbrain
- Forebrain
What is located in the hindbrain?
- Medulla
- Pons
- Cerebellum
- C on picture
What is the main function of the hindbrain?
Handles the primitive parts without you realizing it
Medulla
- Part of the hindbrain
- Autonomic
- Basic life support functions (breathing, heartbeat, digestion, swallow/cough/vomit)
When people OD on opioids it makes it hard for the body to function normally and care for itself. Where do the opioids bind to the neurons?
Medulla
Pons
- Soma of “reticular activating” neurons
- Responsible for wakefulness (Raphe) /alertness (Locus Coeruleus)
Locus coeruleus
- Used in the pons
- Keeps individuals alert
- Norepinephrine releasing
Raphe
- Used in the pons
- Sleep/wake cycle
- 5-HT-releasing
A drug that induces (heightens) the levels of locus coeruleus and raphe in the pons would result in:
Insomnia
Cerebellum
- Part of the hindbrain
- Motor coordination/balance (execution of learned motor sequences, largely unconscious during execution)
- Practice develops circuitry in the cerebellum
What could result from a tiny stroke in the cerebellum?
- Loss of coordination for well known movements
- An individual losing the ability to stand/walk correctly
E.B. has a tumor growing in his brain. Although he has been an excellent salsa dancer for many years, he is having more and more trouble getting the timing and sequence (pattern) of the steps right. Where is the tumor most likely to be located?
Cerebellum
What 3 nuclei are located in the midbrain?
- Periaqueductal gray (PAG)
- Ventral tegmental area (VTA)
- Substantia nigra
Superior colliculus
- Part of the midbrain/tectum
- Visual coordination of movement
- When you see something odd it makes you want to look at it
Inferior colliculus
- Part of the midbrain/tectum
- Sound localization; auditory coordination of movement
- When you hear a loud boom it will make you look
Periaqueductal gray (PAG)
- Part of the midbrain/tegmentum
- Pain modulation/control area of the brain
- Opioids bind here and disinhibit it
Ventral tegmental area (VTA)
- Part of the midbrain/tegmentum
- Pleasure/motivated behavior
- Major dopamine creating/releasing
Someone who doesn’t want to do anything and experiences little enjoyment most likely has something wrong with their:
Ventral tegmental area (VTA)
Substantia nigra
- Part of the midbrain/tegmentum
- Speed of movement
- Dopamine releasing
What neuron does Parkinson’s disease affect?
Substantia nigra
What is located in the forebrain?
- Thalamus
- Hypothalamus
- Basal ganglia
- Amygdala
- Hippocampus
- Cerebrum (4 lobes)
Thalamus
- Part of the forebrain
- Sensory motor “relay/coordinating station”
- Wanting to move right big toe
What can damage to the thalamus result in?
- Movement disorders
- Lack of movement
Hypothalamus
- Part of the forebrain
- 4F’s: Feeding, fornication, fight, flight
- Sympathetic nervous system activation starts here
What can damage to the hypothalamus result in?
Disruptions in body temperature regulation, growth, weight, emotions
Basal ganglia
- Part of the forebrain
- Habitual movement
Examples of basal ganglia movements
- Swatting away a fly
- OCD
- Having a tick
Example of a hypothalamus function
Waking up hot (past normal time of waking up) and wanting to throw off blankets
What disease affects the basal ganglia?
- Huntington’s disease
- Uncontrolled movement caused by deterioration of this brain area
- Arms don’t stop moving, ultimately develop dementia
Amygdala
- Part of forebrain
- Emotions (particularly fear and anger)
What would damage to the amygdala cause?
Emotional sensitivity
L.C. has become increasingly aggressive over the past few months, often getting into fights after very little provocation. What part of L.C.’s brain may be malfunctioning?
Amygdala
Hippocampus
- Part of the forebrain
- Learning/memory
Example of damage to the hippocampus
- H.M.
- They took part of this brain area out and cured his epilepsy, but he was incapable of learning new things
P.D. recently started taking medication to control epilepsy. Unfortunately, she now finds that she really struggles with coursework; she is spending even more time studying but often has trouble remembering much of what she read the night before? The medication is probably impairing what part of P.D. ‘s brain?
Hippocampus
What are the 4 lobes of the cerebrum
- Occipital lobe
- Parietal lobe
- Temporal lobe
- Frontal lobe
Occipital lobe
- Part of the cerebrum/forebrain
- Simple visual perception
Parietal lobe
- Part of the cerebrum/forebrain
- Somatosensory perception (anterior)
- Complex visual perception (posterior)
Temporal lobe
- Part of the cerebrum/forebrain
- Complex visual perception
- Auditory perception
Frontal lobe
- Part of the cerebrum/forebrain
- Decision making/reasoning: Prefrontal cortex (anterior)
- Planning/control on conscious movement: Motor cortex (posterior)
What does the prefrontal cortex of the frontal lobe do?
Decision making/reasoning
What does the motor cortex of the frontal lobe do?
Planning/control on conscious movement
What might damage to the cerebrum result in?
- Personality disorders
- Loss of senses
S.L. & E.G. each swallow a pill. A half hour later a friend asks them if they want to go to College Hill party, a movie, or stay home. They simply cannot make a decision; they’re having trouble holding all options in mind at the same time. What part of their brains have probably been affected by the pill?
Prefrontal cortex
Homunculus arrangement
Motor and sensory systems are said to be mostly “crossed over” - what does this mean?
- Primary motor cortex axons → crossover at medulla → controls muscles on the other side of the body
- Somatosensory neurons on one side of body axons → crossover in spinal cord → ascent to thalamus, somatosensory cortex on the other side of the brain
What neurons almost completely crossover to the other side of the brain?
- Visual neurons
- Auditory neurons
If a stroke affects the left side of the body, then the stroke most likely occurred on the __ hemisphere of the brain
Right
How is the membrane potential of a neuron maintained at rest (in a “polarized” state, approximately -70 mV)
There are fewer cations inside than outside axon
What causes there to be fewer cations inside that outside the axon for a neuron maintained at rest (-70 mV)
- The Na+/K+ pump is always active
- For every 3+ that flow outside, 2+ flow inside
- channels are closed at rest
- Na+ IN, K+ OUT
When a neuron is in a “resting state” (not firing), it is “polarized” because:
There are more cations outside the neuron than inside it, making the difference in electrical potential from inside to outside the neuron -70 mV
EPSP (excited post synaptic potential)
- Small positive change in membrane potential (depolarization)
- Membrane potential becomes less negative (-65 mV)
IPSP (inhibited post synaptic potential)
- Small negative change in membrane potential (hyperpolarization)
- Membrane potential becomes more negative (-75 mV)
What happens when EPSP (depolarization) occurs?
- Na+ channels open
- More sodium comes in and enters the neuron
What happens when IPSP (hyperpolarization) occurs?
K+ channels open more often –> K+ flows out
OR
Cl- channels open –> Cl- flows in
What causes action potentials?
- Activation of sensory neuron ending (ex. skin, eye, tongue)
- Input from other neurons
How is action potential triggered and conducted along a myelinated axon?
- ) Starts at axon hillock (interneuron)
- ) Travels down axon in a “wave of depolarization”
- ) Refractory period prevents action potential from moving backwards
- ) Opening and closing of ion channels exclusively at the Nodes of Ranvier
- ) This saltatory conduction accelerates the rate at which an action potential travels down an axon
How is action potential triggered and conducted along a unmyelinated axon?
- ) Starts at axon hillock (interneuron)
- ) Travels down axon in a “wave of depolarization”
- ) Refractory period prevents action potential from moving backwards
- ) Slower conduction of action potential
Myelinated vs. unmyelinated action potential initiation and conduction in axons
Insulation by myelin speeds up action potential down the axon; saltatory conduction
Saltatory conduction
- Occurs for myelinated axons
- Involves the opening and closing of ion channels exclusively at the Nodes of Ranvier
Myelinated axons occur in the CNS via
Oligodendrocytes
Myelinated axons occur in the PNS via
Schwann cells
How does a local anesthetic like Novocain prevent action potentials in your sensory nerves?
It blocks the Na+ channels in sensory nerves
How can a poison like TTX (pufferfish) kill you?
It blocks the Na+ channels and stops all nerve firing
What is an example of a demyelinating disease?
Multiple sclerosis (MS)
How does a demyelinating disease like multiple sclerosis lead to slowed movement, or an inability to move?
- The myelin deteriorates which slows down action potential and makes transmission happen slower
- If you lose all of your myelin then it makes it almost impossible
Major steps in chemical neurotransmission
-Synthesis of a neurotransmitter: packaging in vesicles
-Action potential arrives at axon terminal and triggers NT release (exocytosis)
-Neurotransmitter goes across the synapse and binds to receptors on postsynaptic neuron
Neurotransmitter goes off the receptor and NT signaling is terminated via:
-Reuptake
-Degradation
Describe step 1 in chemical neurotransmission
Synthesis of a neurotransmitter: packaging in vesicles
Describe step 2 in chemical neurotransmission
- Action potential arrives at axon terminal and triggers NT release (exocytosis)
- Ca++ channels open, Ca+ flows IN
- Ca+ causes vesicle membranes to fuse with axon terminal membrane
- NT is released into synapse
Describe step 3 in chemical neurotransmission
- NT molecules cross synapse and bind to receptors on post-synaptic neuron
- Which receptor the NT binds to determines if the neuron is excited or inhibited
Describe step 4 in chemical neurotransmission
Neurotransmitter goes off the receptor and NT signaling is terminated via: Reuptake of NT
Describe step 5 in chemical neurotransmission
- Neurotransmitter goes off the receptor and NT signaling is terminated via: Enzymatic degradation
- Most NTs go back into axon terminal that released them, by the use of a transporter protein, but some are broken down by enzyme in the synapse and thus inactivated
Ionotropic receptor
- Receptor is an ion channel → NT binding causes ion channel to open (or close)
- Fast activation that is brief
- No lasting consequences
Metabotropic receptor
- When a NT binds here a subunit of the G protein breaks off and either binds to an ion channel of stimulates synthesis of second messenger
- Activation is slower and longer
- Neuron “metabolism” changes and can change gene expression
Glutamate
- NT of the amino acid class
- 3 glutamate receptor types: all are ionotropic & open Na+ channels so +
- Always excitatory → increases the neurons action potential
GABA
- NT of the amino acid class
- 2 GABA receptor types: 1 ionotropic (opens Cl- channels); 2 metabotropic (opens K+ channels) so -
- Always inhibitory → decreases the neurons action potential
Example of a behavior or experience that dopamine (DA) is involved in
- Mood
- Cognition
- Movement
Drug that alters dopamine (DA)
L-Dopa increases synthesis to treat Parkinson’s disease
3 neurotransmitters of the monoamine class
- Dopamine
- Serotonin
- Norepinephrine
Example of a behavior or experience that norepinephrine is involved in
Alertness
Example of a behavior or experience that serotonin is involved in
- Mood
- Vision
- Appetite
Drug that alters serotonin
SSRI’s block reuptake of 5-HT and increase NT action
Two main functions of acetylcholine (ACh)
- Movement
- Memory
How can diet influence your mood or behavior by influencing your neurotransmitter and ion levels?
- There are essential amino acids that the body can’t make
- Neurons won’t fire without electrolytes
- Neurons need Na+, K+, Mg+, Ca+
Describe the circuitry underlying the knee-jerk reflex, including what types of neurons and what neurotransmitters are involved
- Tap on patellar tendon stretches it
- Sensory neuron fires into spinal cord
- Excited motor neuron goes back out to quad, releases glutamate, acetylcholine is released and the muscle contracts
- Sensory neuron activates interneuron and inhibits motor neuron that goes out to the hamstring so the hamstring relaxes
Why do people who suffer from myasthenia gravis experience “muscle weakness”
People with myasthenia gravis experience muscle weakness because the disease results in a loss of acetylcholine receptors
What type of medication is used to help myasthenia gravis patients move more normally (how does this drug work)?
- Tensilon drug
- AChE inhibitors prevent AChE from breaking down ACh
- Increase in ACh
Agonist
Enhances neurotransmitter action
Antagonist
Inhibits neurotransmitter action
Novocain
- Antagonist
- Blocks Na+ channels in sensory nerves
Botox
- Antagonist
- Release
- Decreases release of ACh
Nicotine
- Agonist
- Binding
- Mimics ACh at 1 type of cholinergic receptor
Oxycotin
- Agonist
- Binding
- Mimic endorphin at opioid receptors (decrease pain)
Amphetamines
- Agonist
- Release
- Increase release of monoamines
SSRI’s
- Agonist
- Reuptake
- Blocks reuptake, thereby increasing NT action
MAO (antidepressants)
- Agonist
- Enzymatic degradation
- MAO inhibitors prevent MAO from breaking down monoamines, thereby increased NT action
Technologies that are used to examine the structure of the living human brain
- Cerebral angiography
- CT scan
- MRI
Cerebral angiography
- Examine structure of the living human brain
- Inject dye into the cerebral artery, then x-ray to localize brain circulatory system abnormalities (aneurysm)
CT scan
- Examine structure of the living human brain
- X-rays 8-9 horizontal brain sections then reconstructs as 3D picture (detect tumor)
MRI
- Examine structure of the living human brain
- Magnetic field x radio wave scan; higher resolution than CT scan so better for softer tissue like brain (localize tumor or stroke)
Technologies that are used to examine function (and dysfunction) of the living human brain
- PET
- fMRI
PET scan
- Examine function (and dysfunction) of the living human brain
- Radiolabeled glucose injected into the carotid artery → glucose taken up by the most active neurons → scan for areas with high radioactivity (high brain activity)
- Can visualize specific receptors and whether they’re activated or not during particular tasks
fMRI
- Examine function (and dysfunction) of the living human brain
- Measures oxygen utilization (highly active brain areas take up more oxygenated blood)
Approach in humans to determine the role of certain brain structures and certain neurotransmitters/receptors/ion channels in particular behaviors or experiences
- Transcranial stimulation
- Comparing function in those who lack certain brain structures (or have damage) with those who have intact brains
Transcranial stimulation
- Interrupt or stimulate cerebral cortex neuron activity
- Humans or mice
Approach in animals to determine the role of certain brain structures and certain neurotransmitters/receptors/ion channels in particular behaviors or experiences
- Lesion
- Deep electrical brain stimulation
- Drug microinjection
- Genetic “knock-out”
Non-invasive physiological measures that can be used in human studies of stress and emotion
- EEG, EOG, EMG, EKG (electro - encepalo/oculo/myo/cardio - gram)
- Skin conductance: HR (heart rate), BP (blood pressure), temp; to assess sympathetic nervous system activation
The 3 major divisons of mammalian brains are often described in terms of the complexity of behaviors/processes they control, as follows:
The more posterior/ventral the brain region, the more basic (and unconscious) the functions
An EPSP is most accurately described by which statement:
A change in membrane potential from approximately -70mV to -60mV which is due to brief opening of some Na+ channels, allowing Na+ to flow into the neuron
Resting membrane potential of neurons is maintained at approximately -70mV by which of the following processes
The Na+/K+ pumps transport more cations (Na+) out than cations (K+) in
Jill fell and incurred injury to the ventral/posterior aspect of the head, should we be concerned?
Yes, because her medulla/pons/cerebellum may be damaged which control her vital functions and coordinated movement
K.T. has a tumor pressing against the hypothalamus. Symptoms that he would be most likely to experience include:
- Change in appetite
- Body temperature
- Libido (interest in sex)
Major steps of chemical neurotransmission
Synthesis –> Exocytosis –> Binding –> reuptake and/or enzymatic degradation
When a neurotransmitter binds to a metabotropic receptor:
A G protein is activated, which then opens (or closes) an ion channel associated with the receptor; additionally, the neuron’s intracellular events may be altered (e.g. gene expression in the nucleus of the neuron)
A simple neural circuit like the knee-jerk reflex is most accurately described by which of the following:
Stretching the patellar tendon activates sensory neurons; these neurons release glutamate, which excites motor neurons that terminate on the quadriceps muscle; the motor neurons release ACh which causes quadriceps muscle contradiction and extension of the lower leg
What happens at transcription? DNA → Transcription → RNA →Translation → Protein → Trait
A strand of messenger RNA is transcribed from one of the exposed DNA strands and carries the genetic code from the nucleus into the cytoplasm of the cell
What happens at translation? DNA → Transcription → RNA →Translation → Protein → Trait
In the cytoplasm, the strand of messenger RNA attaches itself to a ribosome. The ribosome moves along the strand translating each successive condon into the appropriate amino acid
Sympathetic changes are indicative of __
Physical arousal
Parasympathetic changes are indicative of __
Physical relaxation
What nerves stimulate, organize, and mobilize energy resources in threatening situations?
Sympathetic
What nerves act to conserve energy?
Parasympathetic
Primary NT of the PSNS
Acetylcholine
Body functions stimulated by the parasympathetic nervous system (PSNS)
- Sexual arousal
- Salivation
- Urination
- Digestion
The autonomic NS of the PNS controls:
Involuntary muscles
Fight or flight (energy expanding)
Sympathetic
Rest and digest (energy conserving)
Parasympathetic
The somatic NS of the PNS controls:
- Voluntary muscles
- Conveys sensory info to CNS
- Sensory (in) & motor (out) nerves
Ionotropic receptors are associated with _
Ion channels
Metabotropic receptors are associated with _
- Signal proteins
- G proteins
Exocytosis
Process of neurotransmitter release
Z.V. feels very depressed, and has trouble getting up in the morning - especially in the winter, she feels like she could just stay in bed and “hibernate” all day. It is likely that neurons in Z.V.’s _________ and/or _________ are not firing at peak levels
- Raphe nucleus
- Locus ceruleus
Inhibitory post-synaptic potentials (IPSPs) are generated when an input to a neuron causes:
Cl- channels to open, so that Cl- flows into the neuron
OR
K+ channels to open, so that K+ flows out
Excited post-synaptic potentials (EPSPs) are generated when an input to a neuron causes:
Na+ channels to open, so that Na+ enters the neuron
During an action potential, the primary reason that membrane potential stops rising at its peak is:
Na+ channels close, so that Na+ can no longer enter the neuron
Myelinated neurons conduct action potentials at speeds of up to 60 m/sec because:
Saltatory conduction occurs in myelinated axons, which means that the action potential “jumps” myelinated segments of the axon
Differences between ionotropic and metabotropic receptors include:
Ionotropic receptors are located on (are part of) ion channel proteins, whereas metabotropic receptors are on proteins that are separate from but adjacent to ion channels
When a nt binds to its receptor, an action potential will occur if:
Binding causes Na+ channels to open, and multiple EPSPs occur simultaneously so that the neuron’s firing threshold (-55 mV) is reached
2 “cholinergic” receptor types of acetylcholine (ACh)
- One ionotropic: Gates Na+, so +
- One metabotropic: Gates K+, so -
2 main functions of acetylcholine (ACh)
- Chemical that motor neurons release to activate muscles
- Also used for memory
What does curare do to acetylcholine (ACh)
- It blocks ACh receptors and is used as a paralytic
- Used during surgery to make sure patient doesn’t move
How can diet affect genetics/brain function
If you put yourself on a diet that is absent of essential amino acids that our bodies can’t make, then your brain function will be impaired
Examples of food with glutamate (which is an essential amino acid for neurotransmitters)
- Tomatoes
- Mushrooms
- Cheese
Deep brain stimulation for Parkinson’s disease
- Used to quiet tremors and dystonia (abnormal muscle tone/rigidity)
- Electrode is placed in or near basal ganglia, since the substantia nigra neurons are no longer releasing sufficient DA to the basal ganglia
