Exam 2 Flashcards
What are the roles of the Hypothalamus?
-controls the five F’s: fighting, fleeing/freezing, feeding, and reproduction
-Controls the autonomic nervous system
-controls the endocrine system via the pituitary gland
-regulates circadian rhythms via the suprachiasmatic nucleus
What does the anterior pituitary gland do?
It indirectly releases hormones
What does the Posterior pituitary gland do?
It directly releases hormones
What are the roles of the sympathetic nervous system?
-prepares body for action
- “fight or flight”
-Spinal cord
-neurotransmitters
Preganglionic: acetylcholine
Post: norepinephrine
What are the two neurotransmitters released by the sympathetic nervous system?
acetylcholine and norepinephrine
What are the roles of the Parasympathetic nervous system?
-Para-> around
-restorative function
- “rest and digest”
-spinal cord-> ganglia near end organs-> end organ
Neurotransmitter: acetylcholine
What is the neurotransmitter released by the parasympathetic nervous system?
acetylcholine
What are the roles of the Cerebral Cortex?
-Contains hemispheres: right and left
- gyrus/ gyri (bumps)
-Sulcus/ sulci, fissures (grooves)
-large surface area as a result of folding (increase in surface area)
What are the roles of the Cerebellum?
- “little brain”
-Dorsal to pons
-movement coordination, classical conditioning (associative learning)
what part of the brain are the tectum and tegmentum located in?
The midbrain
What are the roles of the Tectum?
- “roof”
-superior colliculus (reflexive orienting of eyes, head, ears)
-inferior colliculus (sound/ auditory processing)
What are the roles of the Tegmentum?
- “floor”
- Species typical movement sequences (cat hiss, pouncing)
- Cranial nerves
- Nuclei that release modulatory neurotransmitters
-dopamine
-norepinephrine- serotonin
What neurotransmitters are released by the nuclei of the tegmentum?
dopamine
norepinephrine
serotonin
Roles of the glial cells
-Glia means glue
-functions: structural support, metabolic support, brain development, neural plasticity
What are different types of glial cells?
Astrocytes, Myelinating cells (oligodendrocytes, schwann cells, microglia)
What are the roles of Astrocytes?
- “star shaped”
-physical and metabolic support
-blood brain barrier
-regulate concentration of key ions for neural communication
-regulate concentration of key neurotransmitters
-shape brain development
-regulate local blood flow
-regulate/ influence communication between neurons - disruption linked to cognitive impairment, disease
What are the roles of Myelinating Cells?
- Produce myelin or myelin sheath.
-white, fatty substance
-surrounds fatty neurons
-The “white” in white matter
-Provide electrical/ chemical insulation
-make neuronal messages faster, less susceptible to noise
What is the role of Oligodendrocytes?
in brain and spinal cord, 1 to many neurons
What are the role of Schwann Cells?
in peripheral nervous system: 1 to 1, facilitate neuro-regeneration
What are the roles of Microglia?
clean- up damaged, dead tissue. Prune synapses in normal development and disease. Disruptions in microglia pruning-> impaired functional brain connectivity and social behavior
Where is Na+ concentrated?
Outside the cell
Where is K+ concentrated?
Inside the cell
Where is A- concentrated?
Inside the cell
Where is Cl- concentrated?
Outside the cell
What are the steps/ phases of action potential?
1.Onset at threshold
2. Rising phase-depolarization
3.Peak- at positive voltage
4.Falling phase- repolarization
5.Reset-refractory period
What happen during the onset at threshold?
+ input makes membrane potential more positive
What happens during rising phase?
Voltage-gated Na+ channels open, Na+ flows in
What happens at the peak?
-Voltage-gated Na+ channels close and deactivate; Voltage-gated K+ channels open
What happens at the falling phase?
-K+ flows out
What happens at the reset/ refractory period?
-Na+/ K+ pump restores [Na+], [K+]; voltage- gated K+ channels close
What are the steps in neurotransmitter release?
- Action potential propagates from soma
- Action potential arrival at synapse triggers neurotransmitter (NT) release
- NTs diffuse across synaptic cleft & bind to next neuron
What occurs when the action potential propagates to the soma?
- Soma receives input from dendrites
- Axon hillock sums/integrates
- If sum > threshold, AP “fires”
What occurs when the action potentials arrives at the synapse?
- Voltage-gated calcium Ca++ channels open
- Ca++ causes synaptic vesicles to bind with presynaptic membrane & merge with it
- NTs released via exocytosis
What occurs when the NT’s diffuse across the synaptic cleft and bind to the next neuron?
- NTs bind with receptors on postsynaptic membrane
- Receptors respond
- NTs unbind, are inactivated
What are the two amino acid neurotransmitters?
Glutamate and GABA
What the role of Glutamate?
- Primary excitatory NT in CNS (~ 1/2 all synapses)
- Role in learning (via NMDA receptor)
- Transporters on neurons and glia (astrocytes and oligodendrocytes)
- Linked to umami (savory) taste sensation, think monosodium glutamate (MSG)
Which neurotransmitter is the primary excitatory in the CNS?
Glutamate
What is the role of GABA?
- Primary inhibitory NT in CNS
- Excitatory in developing CNS, [Cl-] in»_space; [Cl-] out
- Binding sites for benzodiazepines (e.g., Valium), barbiturates, ethanol, etc.
- Synthesized from glutamate
- Inactivated by transporters
What is the primary inhibitory NT in the CNS?
GABA
When is GABA excitatory?
To help develop [Cl-] in»_space; [Cl-] out
What is the ionotropic type of GABA?
GABA-A, permeable to Cl-
What is the metabotropic type of GABA?
GABA-B, permeable to K+
What are the roles of Acetylcholine?
- Primary NT of CNS output
- Somatic nervous system (neuromuscular junction)
- Autonomic nervous system
o Sympathetic branch: preganglionic neuron
o Parasympathetic branch: pre/postganglionic - Inactivation by acetylcholinesterase (AChE
What neurotransmitters are monoamines?
Dopamine
Norepinephrine
Serotonin
Histamine
Melatonin
What are the roles of dopamine?
- Released by two pathways that originate in the midbrain tegmentum
o Substantia nigra -> striatum, meso-striatal projection
o Ventral tegmental area (VTA) -> nucleus accumbens, ventral striatum, hippocampus, amygdala, cortex; meso-limbo-cortical projection - DA Disruption linked to
o Parkinson’s Disease (mesostriatal)
DA agonists treat (agonists facilitate/increase transmission)
o ADHD (mesolimbocortical)
o Schizophrenia (mesolimbocortical)
DA antagonists treat
o Addiction (mesolimbocortical) - DA Inactivated by
o Chemical breakdown
o Dopamine transporter (DAT)
Where is dopamine release?
In two pathways in the Tegmentum, the Substantia nigra, and the Ventral tegmental area
What can disruption of dopamine lead to?
Parkinson’s disease, ADHD, Schizophrenia
What are the roles of Norepinephrine?
- Role in arousal, mood, eating, sexual behavior
- Released by
o locus coeruleus in pons/caudal tegmentum - Released by Sympathetic Nervous System (SNS) onto targets in PNS
- Monoamine oxidase (MAO) inactivates monoamines in neurons, glial cells
- Monoamine oxidase inhibitors (MAOIs) increase NE, DA
o Inhibiting inactivation ~ -(-1) = + 1 - Treatment for depression, but side effects (dry mouth, nausea, headache, dizziness)
Where is Norepinephrine released?
the Locus coeruleus in the pons/ caudal tegmentum, and the SNS onto targets in the PNS
What are side effects of Norepinephrine?
Treatment for depression, but side effects (dry mouth, nausea, headache, dizziness)
What are the roles of Serotonin
- Released by raphe nuclei in brainstem
- Role in mood, sleep, eating, pain, nausea, cognition, memory
- Modulates release of other NTs
- Most of body’s 5-HT regulates digestion
o via Enteric Nervous System (in PNS) - 5-HT receptors
o Seven families (5-HT 1-7) with 14 types
o All but one metabotropic - Ecstasy (MDMA) disturbs serotonin
- So does LSD
- Fluoxetine (Prozac)
o Selective Serotonin Reuptake Inhibitor (SSRI)
o Inhibits reuptake -> increases extracellular concentration
o Treats depression, panic, eating disorders, others - 5-HT3 receptor antagonists are anti-mimetics used in treating nausea
Where is Serotonin released?
The raphe nuclei in the brainstem
Increases in Serotonin can lead to?
Selective Serotonin Reuptake Inhibitor (SSRI)
o Inhibits reuptake -> increases extracellular concentration
o Treats depression, panic, eating disorders, others
* 5-HT3 receptor antagonists are anti-mimetics used in treating nausea
What is the role of Histamine?
o Metabotropic receptors
o Role in arousal/sleep regulation
* In body, part of immune response
Where is Histamine released?
- In brain, released by hypothalamus, projects to whole brain
What is the role of Melatonin?
- Hormone released by pineal gland into bloodstream
- Concentrations vary over the day, peak near bedtime
- Release regulated by inputs from hypothalamus
Where is Melatonin released?
- Hormone released by pineal gland into bloodstream
What are the roles of an Ionotropic Receptor?
o Recepter+ion channel
Ligand-gated
o Open/close ion channel
o Ions flow in/out depending on membrane voltage and ion type
o Fast-responding (< 2 ms), but short-duration effects (< 100 ms)
What are the roles of metabotropic receptors?
o Trigger G-proteins attached to receptor
o G-proteins activate 2nd messengers
o 2nd messengers bind to, open/close adjacent channels or change metabolism
Slower, but longer-lasting effects
What doe receptors generate?
postsynaptic potentials (PSPs)
What are postsynaptic potentials (PSPs)
o Small voltage changes
o Amplitude scales with # of receptors activated
o Number of receptors activated ~ # of vesicles released
What are Excitatory PSPs (EPSPs)?
o Depolarize neuron (make more +)
o Move membrane potential closer to threshold
What are Inhibitory (IPSPs)?
o Hyperpolarize neuron (make more -)
Move membrane potential away from threshold
What are the roles of Hormones?
- Chemicals secreted into blood
- Act on specific target tissues via receptors
- Produce specific effects
Can a substance be a neurotransmitter and a hormone?
Yes, if the substances are 1) released by neurons, 2) bind to neurons, and 3) bind to other cells in the body.
What are the substances that are both neurotransmitters and hormones?
Substances that are both hormones and neurotransmitters
* Melatonin
* Epinephrine/adrenaline
* Oxytocin
* Vasopressin
Where are Oxytocin and AVP released?
- Hypothalamus (paraventricular nucleus, supraoptic nucleus) to Posterior pituitary
What is the role of Oxytocin?
- Targets milk ducts in breast tissue, also in sexual arousal, vaginal contractions during birth
What is the role of Arginine Vasopressin (AVP)
also known as anti-diurectic hormone (ADH)
What is the role of cortisol?
cortisol-related receptors widespread in brain
* increases blood glucose, anti-inflammatory
* negative consequences of prolonged exposure
HPA axis/ SAM axis?
- Neural response
o Sympathetic Adrenal Medulla (SAM) response
o Sympathetic NS activation of adrenal medulla, other organs
o Releases NE and Epi - Endocrine response
o Hypothalamic Pituitary Adrenal (HPA) axis - Hypothalamus
o Corticotropin Releasing Hormone (CRH) - Anterior pituitary
o Adrenocorticotropic hormone (ACTH) - Adrenal cortex
o Glucocorticoids (e.g., cortisol)
increases blood glucose, anti-inflammatory
negative consequences of prolonged exposure
o Mineralocorticoids (e.g. aldosterone)
Regulates Na (and water) retention in kidneys
What are the Principles of Evolution?
- Life forms existing in the Earth’s past differed from those living today
- New generations of life forms inherit properties from their predecessors
- New life forms evolved as a result of mutations, selection pressures, and geological events
- Greater reproductive success (more offspring) for some, not others
What are the Milestones of history of life on Earth?
- Fossil
o Fossil dating (radiometric) - Geological
o Where fossils are found relative to one another (relative dating)
o How long it takes to form layers - Molecular
o Similarities between vastly different species (e.g., in neurotransmitters, receptors, metabolic pathways, etc.) - Genetic
o Rates of mutation
o Developmental patterns of gene expression - Anatomical
How do nervous systems differ?
- Body symmetry
o radial
o bilateral - Segmentation
- Centralized vs. distributed function
- Cephalization: sense organs & nervous system concentrated in anterior
- Encasement in bone (vertebrates)
How are nervous systems similar?
- Similarities in patterns of early nervous system development
o across vastly different species
o with very distant (in time) common ancestors
o limited number of ways to build nervous systems that successfully regulate behavior - Vertebrates have similar brain plans
- Species differ in relative size of parts
- Brain sizes scale with body size
Brain size scales with body size (more or less) - Mammals and birds have big brains
- Some animals have big brains for their bodies
o Humans
o Crows
o Porpoises - Bigger than expect brains (relative to average) = high ‘encephalization factor’
- Brain size scales with body size (more or less)
- Mammals and birds have big brains
- Some animals have big brains for their bodies
o Humans
o Crows
o Porpoises - Bigger than expect brains (relative to average) = high ‘encephalization factor’
- But in primates, including humans
o Olfactory bulbs small
o Cerebellum comparable to other mammals
What is the Ionotropic receptor of Glutamate?
AMPA, permeable to Na+, K+
What is the metabotropic receptor of Glutamate?
NMDA, permeable to Ca++
