phys psych lecture exam 2

glutamate

• amino acid class of nt

• from diet

• major pathways:

  • cortex to cortex

  • cortex to basal ganglia

  • btwn cortex and thalamus

• cleared:

  • EAAT in astrocytes, pre and post neurons

  • glutamine synthase breaks it down

gaba

• amino acid class of nt

• glutamic acid + GAD → x

• cleared:

  • x transporters (GAT) in astrocytes and neurons

  • x aminotransferase breaks down in cytoplasm

co-localization

• some neurons contain more than one type of nt and co-release them or release individually

neuropeptides

• 2 or more aa linked

• contained in large dense-core vesicles

• large-molecule NTs released gradually in response to multiple APs

• synthesized in soma

• used as NTs, neuromodulators, and as hormones in PNS

• destroyed by enzymes outside of terminal; no reuptake or recycling

large dense-core vesicles

• contain peptides

• made in soma

• transported to terminal via kinesin along microtubules

ionotropic glutamate receptors

• AMPA

  • controls Na+ channel

• NMDA

  • permits passage of Na+ and Ca+

  • blocked by Mg2+ ion

    • needs co-activation by glutamate and glycine and partial depolarization from AMPA to release block

• kainate

  • controls Na channel

metabotropic glutamate receptor

• mGluRs

• at least 8 subtypes

• some are autoreceptors

gaba-a receptor

• ionotropic

• Cl- channel

• benzodiazepines, barbies, alcohol

gaba-b receptor

• metabotropic

• activity opens K+ channel for efflux

gaba-c receptor

• ionotropic

• Cl- channel

• retina

glycine

• inhibitory

• ionotropic receptor

• controls Cl- channel

• sometimes co-released w GABA

  • rapid, long-lasting IPSPs

• cleared:

  • GlyT1 transporters in astrocytes and neurons

  • broken down by cleavage systems

acetylcholine

• implicated in Alzheimer’s for loss of x neurons

• projection systems originate in:

  • pons/midbrain

    • REM sleep

  • basal forebrain

    • learning, memory

dopamine

• monoamine/catecholamine class

• synth from diet

• mesostriatal pathway

  • substantia nigra

  • loss of x disrupts entire basal ganglia-thalamo-cortical loop for movement inhibition and initiation

• mesolimbocortical pathway

  • ventral tegmental area

    • to NAc for reinforcement

  • to pfc for memory, learning, attention

  • drives wanting food

• cleared:

  • DAT transporter

  • broken down by MAO (needs reuptake) or COMT (before reuptake)

dopamine receptors

• all metabotropic

• D1 & D5 excitatory

• D2-D4 inhibitory

NE

• monoamine/catecholamine class

• released from locus coeruleus in pons and lateral tegmental system in midbrain

• excitatory

• important for sexual behavior, control of appetite, attentiveness to environment

• a1, a2, B1, B2 metabotropic in CNS

• B3 in periphery

• released on innervated tissue of sympathetic and as hormone from adrenal medulla

• Clearing:

  • NET transporter

  • broken down by MAO in cytoplasm or COMT before reuptake

axonal varicosities

• axon collaterals that can release NE and 5-HT

• still require Ca2+ and contain synaptic vesicles

serotonin

• monoamine/indoleamine class

• cell bodies in raphe nuclei throughout medulla, pons, midbrain

• involved in:

  • mood

  • eating

  • sleep, arousal

  • regulation of pain

  • dreaming

  • nausea & vomiting

• all metabotropic receptors except 3

  • 3 for nausea and vomiting

substance p

• co-released w glutamate for significant pain

• neuropeptide

endogenous opioids

• neuropeptides

• diff receptors

• diff neural systems for diff actions

  • pag & spinal cord: dec pain

  • pag: defensive responses

  • reinforcement pathway: pleasure & reward

endorphins

• mu receptors; metabotropic

dynorphins

• kappa receptors; metabotropic

enkephalins

• delta receptors; metabotropic

nitric oxide

• gas NT

  • can’t be stored in vesicles; made on demand in all parts of neuron

  • diffuses in and out

• acts as retrograde transmitter

• acts intracellularly to inc 2nd messenger signaling; doesn’t bind to membrane-bound receptors

• synaptic plasticity, vasodilator

carbon monoxide

• gas neuromodulator/NT

• body produces endogenously at low, controlled lvls

• retrograde transmitter for pre modulation

• blood flow

• inflammation

• synaptic plasticity

• circadian rhythms

hypothalamus

• master integrator: takes inputs from all over brain to take action

• uses neural/homeostatic mech for rapid, targeted control

  • hunger, thirst

• uses neuroendocrine mech for systemic, longer-lasting

  • growth, reproduction

endocrine glands

• ductless and release hormones into body’s bloodstream

exocrine glands

• use ducts to secrete fluids onto body surfaces or into cavities

• saliva, tears, sweat

berthold experiment

• castrated roosters

• found that it was chem signal thru blood not nerves (hormones)

endocrine

• hormone released into bloodstream to act on target tissues

neurocrine

• chem release and diffusion across a synapse

• aka synaptic

autocrine

• released chemical acts on the releasing cell

• autoreceptors

paracrine

• released chem diffuses to nearby target cells

• ex: nitric oxide, histamine

pheromone

• used to communicate btwn individuals of same species

• released into environment

allomone

• released by one species to affect behavior of another

• ex: flowers and insects

general principles of hormone action

• act in gradual fashion

• act by changing probability or intensity of behavior; not direct

• relationship btwn behavior and hormones is reciprocal

  • aggression and more T

  • hormones influence how we behave & behavior can change hormone lvls

• hormone may have multiple effects and one behavior can be affected by several hormones. MANY:MANY relationship

• have pulsatile secretion pattern—in bursts

• some controlled by circadian clocks in brain; growth hormone

• can interact w other hormones and change their effects

• can only affect cells w receptor ptn for it

neuroendocrine cells

• blend neuronal and endocrine function

  • all-or-none

  • faster release

• neurons that release hormones into the blood instead or NT

peptide hormones

• structure of chains of aa

• act rapidly

• bind to receptors on cell surface

• activate G ptn

• enzyme produces 2nd messenger

  • cAMP

  • cGMP

  • IP3 and DAG

steroid hormones

• 4 rings of carbon atoms

  • highly hydrophobic

• genomic action:

  • pass thru cell mem and bind intracellularly

    • act slow

    • bind to DNA and control gene expression

      • long-lasting effects

• non-genomic action:

  • rapid effect involving membrane receptors

steroid receptor coactivators

• needed for cell to respond to steroid-receptor complexes

• 2 diff cells w same steroid receptor can respond diff to steroid if producing diff x

neurosteroids

• steroids synthed w/in CNS

• from cholesterol or to form precursors in blood

• ex: estradiol from T w aromatase

autocrine feedback loop

• endocrine cells release hormone whose presence feeds back on endocrine cells to inhibit further secretion

• ex: somatostatin; digestion

target cell feedback

• hormone acts on its target cells

• bio effect detected by endocrine gland and further release inhibited

• ex: insulin

brain regulation

• hypothalamus drives hormone release from glands

• brain detects effects and exerts negative feedback on hypothalamus

• ex: vasopressin (antidiuretic hormone)

brain and pituitary regulation

• hypothalamus uses releasing hormones to regulate the pituitary’s release of tropic hormones to endocrine cells which releases to target and is feedback

• negative feedback goes to pituitary and hypothalamus

  • shut off both to shut down request

• ex: thyroxine (thyroid hormone)

pituitary gland

• master gland

• releases tropic hormones to endocrine cells

infundibulum

• aka pituitary stalk

• connects pituitary to hypothalamus

• cell bodies in hypo whose axons go to posterior to form hypothalamo-hypophyseal tract

• blood vessels from hypo to anterior pituitary—hypophyseal portal system

posterior pituitary

• aka neurohypophysis

• releases oxytocin and vasopressin

• neurosecretory cells

oxytocin

• peptide hormone released by posterior pituitary

• made in hypo → widespread projections

• reproductive and parenting behavior

• milk letdown reflex

• promotes pair bonds in prairie voles

vasopressin

• made in hypo → widespread projections

• peptide hormone released by posterior pituitary

• aka AVP and ADH

• inc BP, reduce urine output

• facilitates monogamous pair-bonds in male prairie voles

milk letdown reflex

• positive feedback loop

  • amplifies response until baby is satiated

• can become conditioned

  • cry triggering

  • stress inhibits

• oxytocin released by post pituitary bc of hypo cells causes reflex

anterior pituitary

• aka adenohypophysis

• releasing and inhibiting hormones synthesized by hypo cells secreted into hypophyseal portal system and carried to x

• then releases own hormones (mostly tropic)

• influenced by hormone feedback from blood and synaptic inputs from other brain areas

tropic hormones

• travel thru bloodstream and target another endocrine gland throughout body

anterior pituitary hormones

• tropic:

  • FSH

  • LH

  • ACTH

  • TSH

• non-tropic:

  • Prolactin

  • Growth hormone (GH)

• FLAT PEG

• e for beta-endorphins, ACTH can’t be produced w/o

median eminence

• at top of pituitary stalk

• axons of hypothalamic neuroendocrine cells go to x w releasing/inhibiting hormones

HPA

• major hypothalamic-pituitary axis

• hypothalamus releases CRH to ant pit (releasing)

• ant pit releases ACTH (tropic) to adrenal cortex

• release of corticosteroids

HPT

• major hypothalamic-pituitary axis

• hypo releases TRH to ant pit

• ant pit releases TSH to thyroid

• release of thryoid hormones T4 & T3

• negative feedback

HPG

• major hypothalamic-pituitary axis

• hypo releases GnRH or GnIH to ant pit

• ant pit releases LH or FSH to gonads

• testes release androgens and ovaries release estrogen & progestins

adrenal medulla

• located on top of each kidney

• releases EPI and NE

• controlled by symp ns

adrenal cortex

• secretes steroid hormones/corticosteroids

  • glucocorticoids (cortisol)

  • mineralcorticoids

    • affect ion conc in tissues

  • sex steroids (DHEA, androstenedione)

    • contribute to pubic & underarm hair in women

cortisol

• released by adrenal cortex

• involved w stress, glucose metabolism, supressing inflammation

• exerts negative feedback on hypo and pit

goiter

• swelling of thyroid gland from iodine deficiency

• thyroid hormones depend on supply from diet

congenital hypothyroidism

• no thyroid hormone production

• causes intellectual disability

• newborn detection allows early treatment by modifying diet

kisspeptin

• hypothalamic peptide involved in onset of puberty

• stimulates GnRH neurons in hypo which stimulates ant pit to release FSH and LH

LH

• released by ant pit

• to leydig cells to produce T

• to ovary

FSH

• released by ant pit

• to sertoli cells to support spermatogenesis

• to ovaries

estrogens

• released by ovaries in HPG axis

• promote development of female reproductive organs

  • female 2nd sex characteristics

progesterone

• released by ovaries in HPG axis

• prepares wall of uterus for fertilized egg to implant

• prepares breast tissue for later milk production

androgens

• produced by testes in HPG

• promote development of male repro organs

• male 2nd sex characteristics

• metabolism of ptns

GnIH/RFRP-3

• released by hypothalamus

• inhibits gonadotropin secretion

• during stress and malnourishment

menstrual cycle

• big surge of LH and FSH during ovulation to stimulate follicle and release of egg

  • spikes in estradiol and progesterone

• oral contraceptives contain synthetic estrogen and progestin for negative feedback on hypothalamus and pituitary

  • suppress GnRH, FSH, LH → no ovulation

pineal gland

• secretes melatonin exclusively at night; can’t secrete in light

  • indoleamine hormone

  • made from 5-HT (tryptophan)

psychosocial short stature

• growth failure due to stress & neglect in early childhood

• not enough sleep

• reduced GH secretion

• removal from stressful environment leads to rapid catch-up growth

reciprocal relationship

• hormonal and neural systems exert reciprocal influences on each other

• experience affects hormone secretion

• hormones affect behavior

• behavior affects future experiences

• brain mediates every step of cycle

drive

• state of tension pushes us or motivates behaviors to meet a need

drive-reduction theory

• suggests disruptions to homeostasis create drives

• reducing those drives motivates us to meet biological needs

ectotherms

• get most heat from environment

• regulate body temp by behavior

  • alligators sunbathing to warm blood

set zone

• 97.9 F for humans

• fluctuates in circadian rhythm

• fluctuates across menstrual cycle

redundancies for thermoregulation

• central detectors (preoptic area of hypo) and some brainstem/spinal cord cells

• peripheral detectors in skin and viscera

preoptic area

• of anterior hypo

• has warm and cold-sensitive neurons

  • warm outnumber cold

posterior hypothalamus

• detects cold

• helps gain and conserve heat

behavioral compensation for thermoregulation

• behaviors to regulate temp

• in ecto and endotherms (integrated w biological mech)

• change exposure of body surface

• change external insulation

• change surroundings

thermogenic brown fat

• burn it to generate heat in endotherms

• nonshivering thermogenesis

  • many newborn mammals

allostasis

• shift set point for a reason

• depending on nature of stressors and prior experience

• ex: heart rate & BP to accommodate current activity lvls

• fever

  • hypo raises set pt and lowers when infection clears (compensatory measures)

intracellular compartment

• 2/3 of water in body

extracellular compartment

• 1/3 of water in body

• interstitial fluid (bathing the cells)

• intravascular (blood plasma)

osmotic thirst

• stimulated by high extracellular solute conc

• water pulled out of cells when salt conc outside is too high

  • cells shrink

• detected by osmosensory neurons

  • in hypo and circumventricular organs →

  • signal POA → SON & PVN of hypo for release of vasopressin → acts on kidney for water conservation

• need to replace only water

• cause is eating a lot of salty food

hypovolemic thirst

• stimulated by low extracellular fluid volume

• water and salts both lost and both need to be replaced

• volume drops while conc stays same

• baroreceptors in blood vessels and heart

  • detect drop in BP →

  • heart dec secretion of ANP →

  • BP recovers, water excretion dec, drinking not inhibited

• ex: bleeding out, sweating

RAAS cascade

• baroreceptors detect drop in vol/pressure →

• heart releases less ANP →

• kidneys release renin→

• angiotensin 2 produced

  • stimulates release of aldosterone to retain salt

  • stimulates hypothalamus

    • promotes vasopressin release

aldosterone

• steroid hormone

• released by adrenal cortex in response to angiotensin 2

• stimulates kidneys to conserve Na+ and facilitates Na-specific hunger

angiotensin 2

• vasoconstriction

• inc release of vasopressin

• aldosterone to retain salt

• acts on CVOs to trigger drinking

glycogen

• complex carb made of glucose molecules

• stored for short term in liver and muscles

glycogenesis

• glucose → glycogen

• promoted by pancreatic hormone insulin

glycogenolysis

• glycogen → glucose

• promoted by glucagon

gluconeogenesis

• converts ptn and glycerol parts of fat into glucose

• to sustain for a little w/o glucose

ketogenesis

• in the liver

• turns fatty acids into ketones

• brain can use as fuel

diabetes mellitus

• chronically high blood glucose bc body lacks insulin or can’t respond to it effectively

• type 1

  • often begins in childhood

  • immune system destroys insulin-producing cells of pancreas

  • little or no insulin made

• type 2

  • body cells become less sensitive to insulin

basal metabolism

• energy used at rest for heat production, maintaining membrane potentials, other basic life-sustaining processes

• adjusts to under or overnutrition to resist losing or gaining weight

metabolic adaptation

• drop in basal metabolism larger than weight loss alone would predict

• can persist long after diet ends

VMH

• dual center of appetite control

• thought lesions cause hyperphagia; inadvertantly got PVN

• suggests satiety center; active will promote not eating

lateral hypothalamus

• dual center model of appetite control

• lesions cause aphagia

• suggests hunger center; active will produce food-seeking behaviors