PSYCH 3M03 Lecture 4: Chapter 4 General Physiological Perspective
18 Jun 2018
School
Department
Course
Professor
Human Nervous System
Head to tail = spinal cord
-
Never need to label full diagram of the body.
-
Central Nervous System
Spinal Cord
-
Hindbrain
Medulla
○
Pons
○
Cerebellum
○
-
Midbrain
Tectum
○
Tegmentum
○
-
Forebrain
Thalamus
○
Hypothalamus
○
Pituitary gland
○
Basal ganglia
○
Limbic system
○
Cerebral cortex
○
And more …
○
-
Structure Reflects Evolution
Evolution has added new aspects of brain.
Neocortex = "new brain"
○
-
Builds up
Fish and aquatic vertebrates have very little to no neocortex, same with
amphibians.
○
Frog > shark > mouse > sheep > humans
○
-
Cerebellar Agenesis
Girl was complaining of intense dizziness, uncoordinated movement, nausea.
-
As a child, she learned to walk very late, developmental delays.
-
No cerebellum
This caused a lack of balance which created the dizziness - leads to nausea
and lack of fine motor movements/coordination.
○
-
8th known case in humans.
-
Even though it's very old, sometimes mutations screw it up.
-
Limbic System
Emotional affect/well-being, memory.
-
Hypothalamus is the control centre of the limbic system.
-
Inside brain, evolutionarily middle-aged.
-
Many things project to the limbic system.
-
Includes amygdala and hippocampus.
-
Hypothalamus
Responsive to:
Light (photoperiod)
○
Olfactory stimuli (pheromones)
○
Steroids (gonadal and adrenocortical)
○
Neural information (central and peripheral)
○
Input from autonomic nervous system
○
Various peptide hormones and other substances from the blood
○
-
Controls influences upon:
Autonomic nervous system
○
Hormones from the pituitary gland
○
Aspects of bodily homeostasis
○
Basic biological drives:
Hunger, thirst, sex, maternal behaviour, fear, rage,
thermoregulation.
§
○
-
Pituitary Gland
Two different regions – posterior and anterior
-
Communication from hypothalamus to anterior pituitary is through transmitters
in the blood
-
Posterior doesn’t respond to hormones released into the blood system but
instead nervous input from the hypothalamus
-
Autonomic Nervous System
3 parts: Sympathetic, Parasympathetic, Enteric (has to do with gut ànot going
to talk about this one)
-
all outputs from sympathetic autonomic nervous system will travel through the
sympathetic ganglia? But they don’t all synapse there.
-
Sympathetic: (fight or flight)1.
Arousal and energy generation
Increases heart rate and respiratory rate
○
Increases blood pressure
○
Inhibits digestion
○
Decreased blood flow to digestive tract and skin
○
Increased blood flow to muscles and lungs
○
Dilation of the pupils
○
-
Intense Arousal
Piloerection
○
Spontaneous urination and defecation
○
-
Fires “quickly”
-
Parasympathetic:2.
Calming and Relaxation
Decreases heart rate and respiratory rate
○
Promotes digestion
○
Increased blood flow to digestive tract
○
Stimulates salivary gland secretion
○
Involved in sleep, sexual responses
○
-
Fires “slowly”
-
Adrenal Gland
Medulla:
Secretes catecholamines in response to sympathetic nervous system
○
-
Cortex:
Secretes steroids (eg. cortisol, DHEA) in response to chemical stimulation
(especially ACTH from pituitary)
○
Textbook figure 4-7
○
-
Hormones and Neurotransmitters
Hormone: a substance released into the bloodstream that communicates with
receptors at some distant site(s).
-
Neurotransmitter: a substance released into the synapse when a presynaptic
neuron fires, is then picked up by a receptor on the dendritic membrane of the
postsynaptic neuron, affecting the probability that the postsynaptic neuron will
fire. There can be excitatory or inhibitory influences on the postsynaptic
neuron.
Textbook figure 4-5
○
-
Neuromodulator: a substance in the brain that affects multiple neurons. The
cerebrospinal fluid and ventricles may be especially important in the mechanism
of neuromodulator action.
Modulating the actions of many different regions of the brain instead of
just one specific one?
○
-
Pheromone: a substance emitted or excreted by one individual that affects the
physiology or behaviour of another member of its species (eg. dogs peeing
everywhere, and then other dogs can tell)
-
Chemical Forms
Steroid hormones
-
Peptide hormones
-
Monoamine hormones and neurotransmitters
-
Acetylcholine
-
1. Steroids
Mainly from gonads (testes, ovaries) and adrenal cortex
-
Generally small molecules that pass readily throughout the system
-
Functions include reproduction, stress, and metabolism
-
Generally lipid (fat) soluble (varies depending on which steroid)
-
May bind to carrier proteins in blood
-
Receptors in various peripheral sites; in the brain predominantly in limbic
system
-
Derived from cholesterol
-
Generally slow acting (hours, days, months)
-
Generally excreted slowly
-
Generally small, lipid soluble molecules that travel throughout the body
-
Act on intracellular receptors – receptors that are inside a cell, therefore, they
travel inside a cell and act on receptors at the cellular level (ribosomes and
nucleus and whatnot)
-
Gonads:
Androgens (e.g. testosterone, androsterone)
○
Estrogens (e.g. estradiol àone of the most potent hormones in
mammals)
○
progesterone
○
-
Adrenal cortex:
Androgens (e.g., testosterone, androsterone)
○
Estrogens (e.g., estradiol)
○
Progesterone
○
Mineralocorticodes (e.g., Aldosterone)
○
Glucocorticoids (e.g., cortisol, corticosterone)
○
-
Removal of ovaries from female mouse (ovariectomy)reduces levels of
androgens and estrogens, but both remain at detectable levels.
-
Androgens produced in the reticularis of adrenal cortex can be converted to
estrogens via the enzyme aromatase.
-
Blocking the aromatase enzyme by administering an aromatase inhibitor to
ovariectomized females reduces estrogens to undetectable levels.
-
If you remove the gonads, we don't see much of a differences because we still
have the adrenal cortex.
-
By administering different enzymes into mice we can regulate the different sex
hormones produced …. Eg. Can change aggression levels by adding more
testosterone.
-
Peptides2.
Consist of various chains of amino acids
-
Can be a few or hundreds of amino acids
-
Produced all over the body, but the ones most relevant to behaviour come
from hypothalamus and pituitary
-
Generally water soluble, fragile, short-acting (milliseconds, seconds, minutes)
Can't cross the blood-brain barrier on their own.
○
-
Peptides from the pituitary control the gonads, adrenal cortex, and thyroid, as
well as having actions of their own
-
The anterior pituitary is controlled chemically by peptides in local circulation
from the hypothalamus
-
There are many peripheral peptides with relevance to behaviour:
Insulin and glucagon from pancreas
○
CCK from gut
○
Leptin from adipose cells
○
-
Do not flow freely to all parts of the body, often because of large molecular size
-
Those produced in periphery may not reach the brain
-
Act on extracellular receptors -- bind to the outside of the cell.
-
Hypothalamu
s
Anterior
Pituitary
Posterior
Pituitary
Gut Pancreas Adipose
CRH
-
GnRH
-
NPY
-
And many
more …
-
ACTH
-
B-endorphin
-
LH, FSH
-
Prolactin
-
And many
more …
-
Oxytocin
-
Vasopressin
(ADH)
-
CCK
-
Ghrelin
-
Insulin
-
Glucago
n
-
Leptin
-
Brain
There are channels in the blood-brain barrier to allow the passing of specific
amino acids/proteins.
-
Ventricles relay many hypothalamic and pituitary hormones.
-
Peptide dynamics in limbic system, within hypothalamus, brainstem, and
elsewhere.
-
TRH vs Oxytocin
TRH
Peptide hormones
○
Hypothalamus
○
-
Oxytocin
Peptide hormone
○
Larger?
○
-
Monoamine Hormones3.
Derived from single amino acids
Not like peptides which are chains.
○
-
Generally fast acting (seconds, minutes)
-
Generally excreted quickly
-
Generally very small, water soluble molecules
-
Act on extracellular receptors.
-
Don't branch out
-
Metabolized differently
-
Catecholamines from Adrenal Medulla
Epinephrine (adrenaline)
○
Norepinephrine (noradrenaline)
○
-
Indolemines from Pineal Gland
Melatonin
○
-
Monoamine Neurotransmitters
Derived from single amino acids.
-
Example:
Tryptophan -> serotonin (5-HT)
○
Tyrosine -> dopamine and norepinephrine
○
Textbook figure 4-5
○
-
Catecholamines
Dopamine
○
Norepinephrine
○
-
Indoleamines
Serotonin (5-HT)
○
-
Other
Glutamate
○
GABA
○
Histamine
○
Glycine
○
-
Catecholamines
Hormones from Adrenal Medulla
In response to SNS
○
Epinephrine (Adrenaline) -- increases response time of SNS reflex
○
Norepinephrine (Noradrenaline)
○
-
Neurotransmitters
Norepinephrine
○
Dopamine
○
-
** Textbook figure 4-11
Know changes
○
Know PNMT: released from adrenal gland, changes norepinephrine to
epinephrine.
○
MAO & COMT break down catecholamines.
○
-
Dopaminergic Pathways:
Involved in general arousal, attention, awakeness, alertness, reward
system.
-
Dopamine cell bodies concentrated in the ventral tegmental are of the
brainstem.
-
Cell bodies in ventral tegmental area ascend via the MFB into the nucleus
accumbens, and some continue on to the forebrain (cortex and limbic
system)
-
Dopaminergic neurons also travel from the hypothalamus to the pituitary,
as well from the substantia nigra to the striatum.
-
Ventral tegmental area > MFB > nucleus accumbens > forebrain (cortex + limbic
systems)
Noradrenergic Pathways
Biggest pathway
-
Noradrenaline cell bodies are concentrated in the locus coeruleus of the
brainstem.
-
Cell bodies in locus coeruleus ascend via the MFB into various limbic sites,
cerebellum, spinal cord, and the cortex.
-
Locus coeruleus > MFB > forebrain (cortex and limbic system)
Indoleamines
Hormones from Pineal
Melatonin
-
-
Neurotransmitters
Serotonin
-
-
Textbook Figure 4-12
Comes from tryptophan which synthesizes.
To serotonin, to melatonin
§
-
MAO degrades, not COMT:
-
-
For our purposes, anything with -onin = indoleamine
-
Serotonergic Pathways
Serotonin cell bodies concentrated in the raphe nuclei of the brainstem.
-
Cell bodies in the raphe nuclei ascend via the MFB into the thalamus,
basal ganglia, various limbic sites, cerebellum, spinal cord, and the cortex.
-
Raphe nuclei > MFB > cortex and limbic system
Melatonin
Pineal secretes more melatonin in darkness -- sleep aid? Maybe.
-
Pineal gland known as "Third Eye"
Because discovered in frogs where it was in the centre of the brain.
§
Frogs skin is so thin, if a predator was behind it casting a shadow
over it, the pineal gland would fire melatonin and the frog would be
aware of the predator.
§
-
Plays role in circadian cycling.
Reproduction, BP, other steroids and peptides.
§
-
Increase weights
-
Figure 4-3 and 4-9
-
Large Neutral Amino Acid Transporter
Supplies large branched amino acids to the brain, which otherwise does not
directly receive them from circulation.
Gets them through the blood-brain barrier.
○
-
Transports tyrosine, phenylalanine, tryptophan, methionine, and the branched-
chained amino acids.
-
These amino acids all compete for the transporter, so a large quantity of one
amino acid can greatly limit the amount of others entering the brain.
-
E.g., serotonin and tryptophan
Serotonin dynamics are very sensitive to dietary tryptophan in many
species, including mice, rats, pigs, monkeys, and humans.
○
Tryptophan loading in diet increases serotonin levels.
○
Serotonin levels decrease after ingestion of amino acid beverage devoid
of tryptophan.
○
-
Aspartame
Bad for you
○
When broken down, you get phenyalanine.
○
May outcompete the tryptophan to the large amino acid transporter.
Decreases the amount of catecholemines and _____ produced by
tryptophan.
§
○
-
Acetylcholine4.
Not derived from an amino acid.
-
Important neurotransmitter of the autonomic nervous system and parts of the
brain.
-
Cholinergic pathway in tagmentum
-
Comes from choline which we get from our diet.
In our bodies, we produce choline-a which we synthesize to make
acetylcholine.
○
-
Evolved in motor system @ neuromuscular junctions.
-
Sympathetic Parasympathetic
Pre-synaptic ACh ACh
Post-synaptic NE ACh
Question#1: Which of the following hormones has rapid effects on the pituitary
gland?
Adrenocorticotropic hormone (ACTH) A)
Neuropeptide Y (NPY)B)
Gonadotropin-releasing hormone (GnRH)C)
Luteinizing hormone (LH)D)
"releasing hormone" tells you the correct answer because the hypothalamus
always sends releasing hormones to the pituitary.
-
Question #2: Substance X is produced by cells in the hypothalamus and released into
the bloodstream. It acts on intracellular receptors throughout the body before being
excreted in urine. Which action(s) does Substance X display.
PheromoneA)
Hormone and pheromoneB)
Hormone and neuromodulatorC)
HormoneD)
Hormones are released into the blood stream
-
Neuromodulators are released into the brain.
-
Chapter 4: General Physiological Perspective
Tuesday, January 30, 2018
4:50 PM
Human Nervous System
Head to tail = spinal cord
-
Never need to label full diagram of the body.
-
Central Nervous System
Spinal Cord
-
Hindbrain
Medulla
○
Pons
○
Cerebellum
○
-
Midbrain
Tectum
○
Tegmentum
○
-
Forebrain
Thalamus
○
Hypothalamus
○
Pituitary gland
○
Basal ganglia
○
Limbic system
○
Cerebral cortex
○
And more …
○
-
Structure Reflects Evolution
Evolution has added new aspects of brain.
Neocortex = "new brain"
○
-
Builds up
Fish and aquatic vertebrates have very little to no neocortex, same with
amphibians.
○
Frog > shark > mouse > sheep > humans
○
-
Cerebellar Agenesis
Girl was complaining of intense dizziness, uncoordinated movement, nausea.
-
As a child, she learned to walk very late, developmental delays.
-
No cerebellum
This caused a lack of balance which created the dizziness - leads to nausea
and lack of fine motor movements/coordination.
○
-
8th known case in humans.
-
Even though it's very old, sometimes mutations screw it up.
-
Limbic System
Emotional affect/well-being, memory.
-
Hypothalamus is the control centre of the limbic system.
-
Inside brain, evolutionarily middle-aged.
-
Many things project to the limbic system.
-
Includes amygdala and hippocampus.
-
Hypothalamus
Responsive to:
Light (photoperiod)
○
Olfactory stimuli (pheromones)
○
Steroids (gonadal and adrenocortical)
○
Neural information (central and peripheral)
○
Input from autonomic nervous system
○
Various peptide hormones and other substances from the blood
○
-
Controls influences upon:
Autonomic nervous system
○
Hormones from the pituitary gland
○
Aspects of bodily homeostasis
○
Basic biological drives:
Hunger, thirst, sex, maternal behaviour, fear, rage,
thermoregulation.
§
○
-
Pituitary Gland
Two different regions – posterior and anterior
-
Communication from hypothalamus to anterior pituitary is through transmitters
in the blood
-
Posterior doesn’t respond to hormones released into the blood system but
instead nervous input from the hypothalamus
-
Autonomic Nervous System
3 parts: Sympathetic, Parasympathetic, Enteric (has to do with gut ànot going
to talk about this one)
-
all outputs from sympathetic autonomic nervous system will travel through the
sympathetic ganglia? But they don’t all synapse there.
-
Sympathetic: (fight or flight)1.
Arousal and energy generation
Increases heart rate and respiratory rate
○
Increases blood pressure
○
Inhibits digestion
○
Decreased blood flow to digestive tract and skin
○
Increased blood flow to muscles and lungs
○
Dilation of the pupils
○
-
Intense Arousal
Piloerection
○
Spontaneous urination and defecation
○
-
Fires “quickly”
-
Parasympathetic:2.
Calming and Relaxation
Decreases heart rate and respiratory rate
○
Promotes digestion
○
Increased blood flow to digestive tract
○
Stimulates salivary gland secretion
○
Involved in sleep, sexual responses
○
-
Fires “slowly”
-
Adrenal Gland
Medulla:
Secretes catecholamines in response to sympathetic nervous system
○
-
Cortex:
Secretes steroids (eg. cortisol, DHEA) in response to chemical stimulation
(especially ACTH from pituitary)
○
Textbook figure 4-7
○
-
Hormones and Neurotransmitters
Hormone: a substance released into the bloodstream that communicates with
receptors at some distant site(s).
-
Neurotransmitter: a substance released into the synapse when a presynaptic
neuron fires, is then picked up by a receptor on the dendritic membrane of the
postsynaptic neuron, affecting the probability that the postsynaptic neuron will
fire. There can be excitatory or inhibitory influences on the postsynaptic
neuron.
Textbook figure 4-5
○
-
Neuromodulator: a substance in the brain that affects multiple neurons. The
cerebrospinal fluid and ventricles may be especially important in the mechanism
of neuromodulator action.
Modulating the actions of many different regions of the brain instead of
just one specific one?
○
-
Pheromone: a substance emitted or excreted by one individual that affects the
physiology or behaviour of another member of its species (eg. dogs peeing
everywhere, and then other dogs can tell)
-
Chemical Forms
Steroid hormones
-
Peptide hormones
-
Monoamine hormones and neurotransmitters
-
Acetylcholine
-
1. Steroids
Mainly from gonads (testes, ovaries) and adrenal cortex
-
Generally small molecules that pass readily throughout the system
-
Functions include reproduction, stress, and metabolism
-
Generally lipid (fat) soluble (varies depending on which steroid)
-
May bind to carrier proteins in blood
-
Receptors in various peripheral sites; in the brain predominantly in limbic
system
-
Derived from cholesterol
-
Generally slow acting (hours, days, months)
-
Generally excreted slowly
-
Generally small, lipid soluble molecules that travel throughout the body
-
Act on intracellular receptors – receptors that are inside a cell, therefore, they
travel inside a cell and act on receptors at the cellular level (ribosomes and
nucleus and whatnot)
-
Gonads:
Androgens (e.g. testosterone, androsterone)
○
Estrogens (e.g. estradiol àone of the most potent hormones in
mammals)
○
progesterone
○
-
Adrenal cortex:
Androgens (e.g., testosterone, androsterone)
○
Estrogens (e.g., estradiol)
○
Progesterone
○
Mineralocorticodes (e.g., Aldosterone)
○
Glucocorticoids (e.g., cortisol, corticosterone)
○
-
Removal of ovaries from female mouse (ovariectomy)reduces levels of
androgens and estrogens, but both remain at detectable levels.
-
Androgens produced in the reticularis of adrenal cortex can be converted to
estrogens via the enzyme aromatase.
-
Blocking the aromatase enzyme by administering an aromatase inhibitor to
ovariectomized females reduces estrogens to undetectable levels.
-
If you remove the gonads, we don't see much of a differences because we still
have the adrenal cortex.
-
By administering different enzymes into mice we can regulate the different sex
hormones produced …. Eg. Can change aggression levels by adding more
testosterone.
-
Peptides2.
Consist of various chains of amino acids
-
Can be a few or hundreds of amino acids
-
Produced all over the body, but the ones most relevant to behaviour come
from hypothalamus and pituitary
-
Generally water soluble, fragile, short-acting (milliseconds, seconds, minutes)
Can't cross the blood-brain barrier on their own.
○
-
Peptides from the pituitary control the gonads, adrenal cortex, and thyroid, as
well as having actions of their own
-
The anterior pituitary is controlled chemically by peptides in local circulation
from the hypothalamus
-
There are many peripheral peptides with relevance to behaviour:
Insulin and glucagon from pancreas
○
CCK from gut
○
Leptin from adipose cells
○
-
Do not flow freely to all parts of the body, often because of large molecular size
-
Those produced in periphery may not reach the brain
-
Act on extracellular receptors -- bind to the outside of the cell.
-
Hypothalamu
s
Anterior
Pituitary
Posterior
Pituitary
Gut Pancreas Adipose
CRH
-
GnRH
-
NPY
-
And many
more …
-
ACTH
-
B-endorphin
-
LH, FSH
-
Prolactin
-
And many
more …
-
Oxytocin
-
Vasopressin
(ADH)
-
CCK
-
Ghrelin
-
Insulin
-
Glucago
n
-
Leptin
-
Brain
There are channels in the blood-brain barrier to allow the passing of specific
amino acids/proteins.
-
Ventricles relay many hypothalamic and pituitary hormones.
-
Peptide dynamics in limbic system, within hypothalamus, brainstem, and
elsewhere.
-
TRH vs Oxytocin
TRH
Peptide hormones
○
Hypothalamus
○
-
Oxytocin
Peptide hormone
○
Larger?
○
-
Monoamine Hormones3.
Derived from single amino acids
Not like peptides which are chains.
○
-
Generally fast acting (seconds, minutes)
-
Generally excreted quickly
-
Generally very small, water soluble molecules
-
Act on extracellular receptors.
-
Don't branch out
-
Metabolized differently
-
Catecholamines from Adrenal Medulla
Epinephrine (adrenaline)
○
Norepinephrine (noradrenaline)
○
-
Indolemines from Pineal Gland
Melatonin
○
-
Monoamine Neurotransmitters
Derived from single amino acids.
-
Example:
Tryptophan -> serotonin (5-HT)
○
Tyrosine -> dopamine and norepinephrine
○
Textbook figure 4-5
○
-
Catecholamines
Dopamine
○
Norepinephrine
○
-
Indoleamines
Serotonin (5-HT)
○
-
Other
Glutamate
○
GABA
○
Histamine
○
Glycine
○
-
Catecholamines
Hormones from Adrenal Medulla
In response to SNS
○
Epinephrine (Adrenaline) -- increases response time of SNS reflex
○
Norepinephrine (Noradrenaline)
○
-
Neurotransmitters
Norepinephrine
○
Dopamine
○
-
** Textbook figure 4-11
Know changes
○
Know PNMT: released from adrenal gland, changes norepinephrine to
epinephrine.
○
MAO & COMT break down catecholamines.
○
-
Dopaminergic Pathways:
Involved in general arousal, attention, awakeness, alertness, reward
system.
-
Dopamine cell bodies concentrated in the ventral tegmental are of the
brainstem.
-
Cell bodies in ventral tegmental area ascend via the MFB into the nucleus
accumbens, and some continue on to the forebrain (cortex and limbic
system)
-
Dopaminergic neurons also travel from the hypothalamus to the pituitary,
as well from the substantia nigra to the striatum.
-
Ventral tegmental area > MFB > nucleus accumbens > forebrain (cortex + limbic
systems)
Noradrenergic Pathways
Biggest pathway
-
Noradrenaline cell bodies are concentrated in the locus coeruleus of the
brainstem.
-
Cell bodies in locus coeruleus ascend via the MFB into various limbic sites,
cerebellum, spinal cord, and the cortex.
-
Locus coeruleus > MFB > forebrain (cortex and limbic system)
Indoleamines
Hormones from Pineal
Melatonin
-
-
Neurotransmitters
Serotonin
-
-
Textbook Figure 4-12
Comes from tryptophan which synthesizes.
To serotonin, to melatonin
§
-
MAO degrades, not COMT:
-
-
For our purposes, anything with -onin = indoleamine
-
Serotonergic Pathways
Serotonin cell bodies concentrated in the raphe nuclei of the brainstem.
-
Cell bodies in the raphe nuclei ascend via the MFB into the thalamus,
basal ganglia, various limbic sites, cerebellum, spinal cord, and the cortex.
-
Raphe nuclei > MFB > cortex and limbic system
Melatonin
Pineal secretes more melatonin in darkness -- sleep aid? Maybe.
-
Pineal gland known as "Third Eye"
Because discovered in frogs where it was in the centre of the brain.
§
Frogs skin is so thin, if a predator was behind it casting a shadow
over it, the pineal gland would fire melatonin and the frog would be
aware of the predator.
§
-
Plays role in circadian cycling.
Reproduction, BP, other steroids and peptides.
§
-
Increase weights
-
Figure 4-3 and 4-9
-
Large Neutral Amino Acid Transporter
Supplies large branched amino acids to the brain, which otherwise does not
directly receive them from circulation.
Gets them through the blood-brain barrier.
○
-
Transports tyrosine, phenylalanine, tryptophan, methionine, and the branched-
chained amino acids.
-
These amino acids all compete for the transporter, so a large quantity of one
amino acid can greatly limit the amount of others entering the brain.
-
E.g., serotonin and tryptophan
Serotonin dynamics are very sensitive to dietary tryptophan in many
species, including mice, rats, pigs, monkeys, and humans.
○
Tryptophan loading in diet increases serotonin levels.
○
Serotonin levels decrease after ingestion of amino acid beverage devoid
of tryptophan.
○
-
Aspartame
Bad for you
○
When broken down, you get phenyalanine.
○
May outcompete the tryptophan to the large amino acid transporter.
Decreases the amount of catecholemines and _____ produced by
tryptophan.
§
○
-
Acetylcholine4.
Not derived from an amino acid.
-
Important neurotransmitter of the autonomic nervous system and parts of the
brain.
-
Cholinergic pathway in tagmentum
-
Comes from choline which we get from our diet.
In our bodies, we produce choline-a which we synthesize to make
acetylcholine.
○
-
Evolved in motor system @ neuromuscular junctions.
-
Sympathetic Parasympathetic
Pre-synaptic ACh ACh
Post-synaptic NE ACh
Question#1: Which of the following hormones has rapid effects on the pituitary
gland?
Adrenocorticotropic hormone (ACTH) A)
Neuropeptide Y (NPY)B)
Gonadotropin-releasing hormone (GnRH)C)
Luteinizing hormone (LH)D)
"releasing hormone" tells you the correct answer because the hypothalamus
always sends releasing hormones to the pituitary.
-
Question #2: Substance X is produced by cells in the hypothalamus and released into
the bloodstream. It acts on intracellular receptors throughout the body before being
excreted in urine. Which action(s) does Substance X display.
PheromoneA)
Hormone and pheromoneB)
Hormone and neuromodulatorC)
HormoneD)
Hormones are released into the blood stream
-
Neuromodulators are released into the brain.
-
Chapter 4: General Physiological Perspective
Tuesday, January 30, 2018 4:50 PM
Human Nervous System
Head to tail = spinal cord
-
Never need to label full diagram of the body.
-
Central Nervous System
Spinal Cord
-
Hindbrain
Medulla
○
Pons
○
Cerebellum
○
-
Midbrain
Tectum
○
Tegmentum
○
-
Forebrain
Thalamus
○
Hypothalamus
○
Pituitary gland
○
Basal ganglia
○
Limbic system
○
Cerebral cortex
○
And more …
○
-
Structure Reflects Evolution
Evolution has added new aspects of brain.
Neocortex = "new brain"
○
-
Builds up
Fish and aquatic vertebrates have very little to no neocortex, same with
amphibians.
○
Frog > shark > mouse > sheep > humans
○
-
Cerebellar Agenesis
Girl was complaining of intense dizziness, uncoordinated movement, nausea.
-
As a child, she learned to walk very late, developmental delays.
-
No cerebellum
This caused a lack of balance which created the dizziness - leads to nausea
and lack of fine motor movements/coordination.
○
-
8th known case in humans.
-
Even though it's very old, sometimes mutations screw it up.
-
Limbic System
Emotional affect/well-being, memory.
-
Hypothalamus is the control centre of the limbic system.
-
Inside brain, evolutionarily middle-aged.
-
Many things project to the limbic system.
-
Includes amygdala and hippocampus.
-
Hypothalamus
Responsive to:
Light (photoperiod)
○
Olfactory stimuli (pheromones)
○
Steroids (gonadal and adrenocortical)
○
Neural information (central and peripheral)
○
Input from autonomic nervous system
○
Various peptide hormones and other substances from the blood
○
-
Controls influences upon:
Autonomic nervous system
○
Hormones from the pituitary gland
○
Aspects of bodily homeostasis
○
Basic biological drives:
Hunger, thirst, sex, maternal behaviour, fear, rage,
thermoregulation.
§
○
-
Pituitary Gland
Two different regions – posterior and anterior
-
Communication from hypothalamus to anterior pituitary is through transmitters
in the blood
-
Posterior doesn’t respond to hormones released into the blood system but
instead nervous input from the hypothalamus
-
Autonomic Nervous System
3 parts: Sympathetic, Parasympathetic, Enteric (has to do with gut ànot going
to talk about this one)
-
all outputs from sympathetic autonomic nervous system will travel through the
sympathetic ganglia? But they don’t all synapse there.
-
Sympathetic: (fight or flight)
1.
Arousal and energy generation
Increases heart rate and respiratory rate
○
Increases blood pressure
○
Inhibits digestion
○
Decreased blood flow to digestive tract and skin
○
Increased blood flow to muscles and lungs
○
Dilation of the pupils
○
-
Intense Arousal
Piloerection
○
Spontaneous urination and defecation
○
-
Fires “quickly”
-
Parasympathetic:
2.
Calming and Relaxation
Decreases heart rate and respiratory rate
○
Promotes digestion
○
Increased blood flow to digestive tract
○
Stimulates salivary gland secretion
○
Involved in sleep, sexual responses
○
-
Fires “slowly”
-
Adrenal Gland
Medulla:
Secretes catecholamines in response to sympathetic nervous system
○
-
Cortex:
Secretes steroids (eg. cortisol, DHEA) in response to chemical stimulation
(especially ACTH from pituitary)
○
Textbook figure 4-7
○
-
Hormones and Neurotransmitters
Hormone: a substance released into the bloodstream that communicates with
receptors at some distant site(s).
-
Neurotransmitter: a substance released into the synapse when a presynaptic
neuron fires, is then picked up by a receptor on the dendritic membrane of the
postsynaptic neuron, affecting the probability that the postsynaptic neuron will
fire. There can be excitatory or inhibitory influences on the postsynaptic
neuron.
Textbook figure 4-5
○
-
Neuromodulator: a substance in the brain that affects multiple neurons. The
cerebrospinal fluid and ventricles may be especially important in the mechanism
of neuromodulator action.
Modulating the actions of many different regions of the brain instead of
just one specific one?
○
-
Pheromone: a substance emitted or excreted by one individual that affects the
physiology or behaviour of another member of its species (eg. dogs peeing
everywhere, and then other dogs can tell)
-
Chemical Forms
Steroid hormones
-
Peptide hormones
-
Monoamine hormones and neurotransmitters
-
Acetylcholine
-
1. Steroids
Mainly from gonads (testes, ovaries) and adrenal cortex
-
Generally small molecules that pass readily throughout the system
-
Functions include reproduction, stress, and metabolism
-
Generally lipid (fat) soluble (varies depending on which steroid)
-
May bind to carrier proteins in blood
-
Receptors in various peripheral sites; in the brain predominantly in limbic
system
-
Derived from cholesterol
-
Generally slow acting (hours, days, months)
-
Generally excreted slowly
-
Generally small, lipid soluble molecules that travel throughout the body
-
Act on intracellular receptors – receptors that are inside a cell, therefore, they
travel inside a cell and act on receptors at the cellular level (ribosomes and
nucleus and whatnot)
-
Gonads:
Androgens (e.g. testosterone, androsterone)
○
Estrogens (e.g. estradiol àone of the most potent hormones in
mammals)
○
progesterone
○
-
Adrenal cortex:
Androgens (e.g., testosterone, androsterone)
○
Estrogens (e.g., estradiol)
○
Progesterone
○
Mineralocorticodes (e.g., Aldosterone)
○
Glucocorticoids (e.g., cortisol, corticosterone)
○
-
Removal of ovaries from female mouse (ovariectomy)reduces levels of
androgens and estrogens, but both remain at detectable levels.
-
Androgens produced in the reticularis of adrenal cortex can be converted to
estrogens via the enzyme aromatase.
-
Blocking the aromatase enzyme by administering an aromatase inhibitor to
ovariectomized females reduces estrogens to undetectable levels.
-
If you remove the gonads, we don't see much of a differences because we still
have the adrenal cortex.
-
By administering different enzymes into mice we can regulate the different sex
hormones produced …. Eg. Can change aggression levels by adding more
testosterone.
-
Peptides2.
Consist of various chains of amino acids
-
Can be a few or hundreds of amino acids
-
Produced all over the body, but the ones most relevant to behaviour come
from hypothalamus and pituitary
-
Generally water soluble, fragile, short-acting (milliseconds, seconds, minutes)
Can't cross the blood-brain barrier on their own.
○
-
Peptides from the pituitary control the gonads, adrenal cortex, and thyroid, as
well as having actions of their own
-
The anterior pituitary is controlled chemically by peptides in local circulation
from the hypothalamus
-
There are many peripheral peptides with relevance to behaviour:
Insulin and glucagon from pancreas
○
CCK from gut
○
Leptin from adipose cells
○
-
Do not flow freely to all parts of the body, often because of large molecular size
-
Those produced in periphery may not reach the brain
-
Act on extracellular receptors -- bind to the outside of the cell.
-
Hypothalamu
s
Anterior
Pituitary
Posterior
Pituitary
Gut Pancreas Adipose
CRH
-
GnRH
-
NPY
-
And many
more …
-
ACTH
-
B-endorphin
-
LH, FSH
-
Prolactin
-
And many
more …
-
Oxytocin
-
Vasopressin
(ADH)
-
CCK
-
Ghrelin
-
Insulin
-
Glucago
n
-
Leptin
-
Brain
There are channels in the blood-brain barrier to allow the passing of specific
amino acids/proteins.
-
Ventricles relay many hypothalamic and pituitary hormones.
-
Peptide dynamics in limbic system, within hypothalamus, brainstem, and
elsewhere.
-
TRH vs Oxytocin
TRH
Peptide hormones
○
Hypothalamus
○
-
Oxytocin
Peptide hormone
○
Larger?
○
-
Monoamine Hormones3.
Derived from single amino acids
Not like peptides which are chains.
○
-
Generally fast acting (seconds, minutes)
-
Generally excreted quickly
-
Generally very small, water soluble molecules
-
Act on extracellular receptors.
-
Don't branch out
-
Metabolized differently
-
Catecholamines from Adrenal Medulla
Epinephrine (adrenaline)
○
Norepinephrine (noradrenaline)
○
-
Indolemines from Pineal Gland
Melatonin
○
-
Monoamine Neurotransmitters
Derived from single amino acids.
-
Example:
Tryptophan -> serotonin (5-HT)
○
Tyrosine -> dopamine and norepinephrine
○
Textbook figure 4-5
○
-
Catecholamines
Dopamine
○
Norepinephrine
○
-
Indoleamines
Serotonin (5-HT)
○
-
Other
Glutamate
○
GABA
○
Histamine
○
Glycine
○
-
Catecholamines
Hormones from Adrenal Medulla
In response to SNS
○
Epinephrine (Adrenaline) -- increases response time of SNS reflex
○
Norepinephrine (Noradrenaline)
○
-
Neurotransmitters
Norepinephrine
○
Dopamine
○
-
** Textbook figure 4-11
Know changes
○
Know PNMT: released from adrenal gland, changes norepinephrine to
epinephrine.
○
MAO & COMT break down catecholamines.
○
-
Dopaminergic Pathways:
Involved in general arousal, attention, awakeness, alertness, reward
system.
-
Dopamine cell bodies concentrated in the ventral tegmental are of the
brainstem.
-
Cell bodies in ventral tegmental area ascend via the MFB into the nucleus
accumbens, and some continue on to the forebrain (cortex and limbic
system)
-
Dopaminergic neurons also travel from the hypothalamus to the pituitary,
as well from the substantia nigra to the striatum.
-
Ventral tegmental area > MFB > nucleus accumbens > forebrain (cortex + limbic
systems)
Noradrenergic Pathways
Biggest pathway
-
Noradrenaline cell bodies are concentrated in the locus coeruleus of the
brainstem.
-
Cell bodies in locus coeruleus ascend via the MFB into various limbic sites,
cerebellum, spinal cord, and the cortex.
-
Locus coeruleus > MFB > forebrain (cortex and limbic system)
Indoleamines
Hormones from Pineal
Melatonin
-
-
Neurotransmitters
Serotonin
-
-
Textbook Figure 4-12
Comes from tryptophan which synthesizes.
To serotonin, to melatonin
§
-
MAO degrades, not COMT:
-
-
For our purposes, anything with -onin = indoleamine
-
Serotonergic Pathways
Serotonin cell bodies concentrated in the raphe nuclei of the brainstem.
-
Cell bodies in the raphe nuclei ascend via the MFB into the thalamus,
basal ganglia, various limbic sites, cerebellum, spinal cord, and the cortex.
-
Raphe nuclei > MFB > cortex and limbic system
Melatonin
Pineal secretes more melatonin in darkness -- sleep aid? Maybe.
-
Pineal gland known as "Third Eye"
Because discovered in frogs where it was in the centre of the brain.
§
Frogs skin is so thin, if a predator was behind it casting a shadow
over it, the pineal gland would fire melatonin and the frog would be
aware of the predator.
§
-
Plays role in circadian cycling.
Reproduction, BP, other steroids and peptides.
§
-
Increase weights
-
Figure 4-3 and 4-9
-
Large Neutral Amino Acid Transporter
Supplies large branched amino acids to the brain, which otherwise does not
directly receive them from circulation.
Gets them through the blood-brain barrier.
○
-
Transports tyrosine, phenylalanine, tryptophan, methionine, and the branched-
chained amino acids.
-
These amino acids all compete for the transporter, so a large quantity of one
amino acid can greatly limit the amount of others entering the brain.
-
E.g., serotonin and tryptophan
Serotonin dynamics are very sensitive to dietary tryptophan in many
species, including mice, rats, pigs, monkeys, and humans.
○
Tryptophan loading in diet increases serotonin levels.
○
Serotonin levels decrease after ingestion of amino acid beverage devoid
of tryptophan.
○
-
Aspartame
Bad for you
○
When broken down, you get phenyalanine.
○
May outcompete the tryptophan to the large amino acid transporter.
Decreases the amount of catecholemines and _____ produced by
tryptophan.
§
○
-
Acetylcholine4.
Not derived from an amino acid.
-
Important neurotransmitter of the autonomic nervous system and parts of the
brain.
-
Cholinergic pathway in tagmentum
-
Comes from choline which we get from our diet.
In our bodies, we produce choline-a which we synthesize to make
acetylcholine.
○
-
Evolved in motor system @ neuromuscular junctions.
-
Sympathetic Parasympathetic
Pre-synaptic ACh ACh
Post-synaptic NE ACh
Question#1: Which of the following hormones has rapid effects on the pituitary
gland?
Adrenocorticotropic hormone (ACTH) A)
Neuropeptide Y (NPY)B)
Gonadotropin-releasing hormone (GnRH)C)
Luteinizing hormone (LH)D)
"releasing hormone" tells you the correct answer because the hypothalamus
always sends releasing hormones to the pituitary.
-
Question #2: Substance X is produced by cells in the hypothalamus and released into
the bloodstream. It acts on intracellular receptors throughout the body before being
excreted in urine. Which action(s) does Substance X display.
PheromoneA)
Hormone and pheromoneB)
Hormone and neuromodulatorC)
HormoneD)
Hormones are released into the blood stream
-
Neuromodulators are released into the brain.
-
Chapter 4: General Physiological Perspective
Tuesday, January 30, 2018 4:50 PM
Document Summary
Never need to label full diagram of the body. Fish and aquatic vertebrates have very little to no neocortex, same with amphibians. Frog > shark > mouse > sheep > humans. Girl was complaining of intense dizziness, uncoordinated movement, nausea. As a child, she learned to walk very late, developmental delays. This caused a lack of balance which created the dizziness - leads to nausea and lack of fine motor movements/coordination. Even though it"s very old, sometimes mutations screw it up. Hypothalamus is the control centre of the limbic system. Various peptide hormones and other substances from the blood. Hunger, thirst, sex, maternal behaviour, fear, rage, thermoregulation. Communication from hypothalamus to anterior pituitary is through transmitters in the blood. Posterior doesn"t respond to hormones released into the blood system but instead nervous input from the hypothalamus. Decreased blood flow to digestive tract and skin. Secretes catecholamines in response to sympathetic nervous system.
