Unit 2: autonomics Flashcards
Composed of the brain and spinal cord
autonomic neurons
group of specialized cells that arise from the edges of the neural tube during embryonic development
-this is where autonomic neurons orginiate
neural crest
which neurons Receive input from sensory neurons and
directs activity of motor neurons that
innervate muscles and glands
autonomic neurons
examples of sensory neurons
baroreceptors and chemoreceptors
examples of motor neurons
cardiac AN and Bronchial AN
what neurons integrate sensory
information and help direct the appropriate
response to maintain homeostasis and
respond to the environment
association/interneurons
what neurons sits btwn sensory neurons and motor neurons.
-found in CNS
-help with reflexes and thinking
association neurons
which neurons have cell bodies in
the spinal cord and just one neuron traveling
from spinal cord to effector
somatic motor
which motor neuron is voluntary, one neuron from CNS to muscle
-you CHOOSE to raise your hand
somatic motor
what are the 2 sets of neurons in pns
preganglionic and postganglionic
what has cell bodies in the brain or spinal
cord and synapses in an autonomic ganglion
preganglionic
what has cell bodies in the ganglion and
synapses on the effector
postganglionic
which neuron originate in the midbrain
or hindbrain or from the thoracic, lumbar, or
sacral spinal cord
preganglionic neuron
what are located in the head,
neck, and abdomen as well as in chains
along either side of the spinal cord
autonomic ganglia
what neuron originate in ganglion
postganglionic neurons
what are internal organs that are controlled by ANS
-smooth and cardiac muscle, glands (involuntary)
visceral effector organs
what are Somewhat independent of innervation and
will not atrophy if a nerve is cut (unlike
skeletal muscle)
visceral effector organs
Target may become even more sensitive to
stimulation
denervation hypersensitivity
why can Cardiac muscle and some smooth muscle
contract rhythmically without nerve
stimulation
because they have intrinsic pacemaker activity. this generates their own impulses to initiate contraction
Autonomic innervation can
speed up or slow down intrinsic
contractions
what can stimulate or
inhibit, depending on the organ and the
receptors
autonomic motor neurons
ex of autonomic motor neurons being able to stimulate or
inhibit, depending on the organ and the
receptors
in the heart
-norepinephrine makes the heart beat fast when excited or exercising
-acetylcholine will slow heart down when rested or relaxed
what does Somatic motor neurons release only
acetylcholine
what is always excited
acetylcholine
what do Autonomic neurons release
acetylcholine and norepinephrine but may
be excitatory or inhibitory
what are the effector organs in somatic motor system
skeletal muscles
are there ganglia in the somatic motor system
no ganglia
what are the number of neurons from cns to effector
1
what type of neuromuscular junction in somatic motor
specialized motor end plate
what are the effect of nerve impulse on muscle in somatic motor
excititory only
type of nerve fibers in somatic motor
fast conducting, thick (9-13um), and myelinated
effects of denervation in somatic motor
flaccid paralysis and atrophy
effector organs in autonomic motor system
cardiac muscle, smooth muscle, and glands
where are Cell bodies of postganglionic autonomic fibers
located in paravertebral, prevertebral (collateral),
and terminal ganglia located
in autonomic motor system
number of neurons from cns to effector in autonomic motor
2
type of neuromuscular junction in autonomic
No specialization of postsynaptic membrane; all
areas of smooth muscle cells contain receptor
proteins for neurotransmitters
effect of nerve impusle on muscles in autonomic motor
Either excitatory or inhibitory
type of nerve fibers in autonomic
Slow-conducting; preganglionic fibers lightly
myelinated but thin (3 μm); postganglionic fibers
unmyelinated and very thin (about 1.0 μm
effects of denervation in autonomic
Muscle tone and function persist; target cells
show denervation hypersensitivity
“stress response”
kicks in when when youre excited, danger, or under stress
sympathetic
“relax and recover”
helps your body chill out, recover, and do things like digest food and sleep
parasympathetic
what is the sympathetic nervous system also called
thoracolumnar dividion
Why is the sympathetic nervous system also called thoracolumbar division?
sympathetic fibers lie between the thoracic & lumbar vertbrae
Why is the parasympathetic nervous system also called the cranio-sacral division?
parasympathetic fibers come out from base of brain & below the tail bone
The sympathetic system has a ________ preganglionic neuron and a _________ postganglionic neuron?
short and long
In which division does the long preganglionic neuron synapse in a ganglion close to or within the target cell?
parasympathetic
epinephrine (E) and norepinephrine (NE) are used as neurotransmitters in what division?
sympathetic
What neurotransmitter is always used in the parasympathetic division?
ACh
in the sympathetic dividion, where do Preganglionic neurons come from
the
thoracic and lumbar regions of the spinal
cord.
where do Preganglionic neurons synapse
in
sympathetic ganglia that run parallel to
the spinal cord
nerve relay station running alongside your spine to help activate fight/flight mode
paravertebral ganglia
Preganglionic neurons synapse in
sympathetic ganglia that run parallel to
the spinal cord. what are these called
paravertebral ganglia
the paravertebral ganglia are connected and form
sympathetic chain of ganglia
By week 4 after conception, three distinct
swellings are seen on the neural tube
Prosencephalon (forebrain)
Mesencephalon (midbrain)
Rhombencephalon (hindbrain)
“control center”
-forebrain
-front/ biggest part of brain that controls thinking, emotions, senses, and voluntary movts.
prosencephalon
what splits into telencephalon (cerebrum) and diencephalon (thalamus.hypothalamus)
prosencephalon
“messenger”
-midbrain
-connects to forebrain and hindbrain, making sure messages get where they need to go
mesencephalon
it remains as the midbrain
mesencephalon
“autopilot”
-hindbrain
-runs basic life functions you dont have to think about. (breathing, balance, basic muscle movt)
rhombencephalon
splits into metencephalon (pons, cerebellum) and myelencephalon (medulla oblongata)
rhombencephalon
Because preganglionic neurons can branch
and synapse in ganglia at any level, there is:
divergence and convergence
One preganglionic neuron
synapses on several postganglionic neurons at
different levels
divergence
Several preganglionic neurons at
different levels synapse on one postganglionic
neuron
convergence
Allows the sympathetic division to act as a
single unit through mass activation and to be
tonically active
sympathetic division
control the abdomen and pelvic organs by releasing nerve signals from spinal cord
collateral ganglia
aka prevertebral ganglia. belings in sympathetic dividision
collateral ganglia
which ganglia has neurotranmitters that release norepinephrine
collateral ganglia
Many of the sympathetic neurons that exit
the spinal cord below the diaphragm do not
synapse in the sympathetic chain of ganglia
-instead, what do they do?
they form splanchnic nerves, which
synapse in collateral ganglia
Collateral ganglia include
celiac, superior
mesenteric, and inferior mesenteric ganglia
Postganglionic neurons innervate organs of the
digestive, urinary, and reproductive systems.
which collateral ganglia controls stomach, liver, pancreas, and intestines
celiac
which collateral ganglia regulates SI and first portion of LI
superior mesenteric
which collateral ganglia controls lower digestive tract, kidneys, and reproductive organs
inferior mesenteric
small triangle shaped gland on top of each kidney apart of endocrine system and regulate various processes like secrete hormones
adrenal gland
The adrenal medulla secretes
epinephrine
and norepinephrine
when does The adrenal medulla secretes epinephrine
and norepinephrine
when stimulated by the
sympathetic nervous system as a part of
mass activation
the adrenal medulla is a
modified ganglion and is innervated directly
by
preganglionic sympathetic neurons
how does the adrenal gland function in stress response
release cortisol to manage stress and adrenaline to boost alertness and energy
how does the adrenal gland function in bloos pressure regulation
aldosterone from cortex helps maintain blood pressure by controlling Na and K levels
Preganglionic neurons come from
the brain
or sacral region of the spinal cord
preganglionic neurons synapse on ganglia located near or in
effector organs; called
terminal ganglia
what neurons do not travel with
somatic neurons
preganglionic
what neurons do travel with
somatic neurons
sympathetic postganglionic neurons
—supply very short
postganglionic neurons to the effectors
Terminal ganglia
The oculomotor, facial, glosso-pharyngeal,
and vagus nerves carry
parasympathetic
preganglionic neurons
in oculomotor nerve, Preganglionic fibers –
exit midbrain and synapse
on the ciliary ganglion
in oculomotor nerve, Postganglionic fibers innervate the
ciliary muscle
of the eye
Facial (VII) nerve: Preganglionic fibers exit
the pons and synapse in
pterygopalatine ganglion and submandibular ganglion
Postganglionic fibers
synapse on nasal mucosa, pharynx, palate, and
lacrimal glands.
Pterygopalatine ganglion
Postganglionic fibers
synapse on salivary glands.
Submandibular ganglion
in glossopharyngeal, Preganglionic fibers
synapse on
otic ganglion.
in glossopharyngeal, Postganglionic
fibers innervate
salivary gland.
Preganglionic fibers exit medulla, branch into several plexi and nerves, and travel to ganglia within effector
organs (heart, lungs, esophagus, stomach,
pancreas, liver, intestines).
-which nerve?
vagus
Preganglionic nerves from the sacral region
of the spinal cord provide innervation to
the
lower part of the large intestine, rectum,
urinary and reproductive organs
Terminal ganglia are located
lower part of the large intestine, rectum,
urinary and reproductive organs
activates the body for
“fight or flight” through the release of
norepinephrine from postganglionic neurons
and the secretion of epinephrine from the
adrenal medulla
sympathetic division
in symp, where is norepinephrine released from
postgang neurons
in symp, where is secretion of epinephrine from
adrenal medulla
Prepares the body for intense physical activity
in emergencies by increasing heart rate and
blood glucose levels and by diverting blood to
skeletal muscles
symp division
Tonically regulates heart, blood vessels, and
other organs
symp division
— means that the symp system is always active at a low level to maintain basic function, even at rest.
allows quick adjustments when needed (during stress, exercise, etc)
tonically regulating
is antagonistic
to the sympathetic division
parasymp
the parasymp division Allows the body to “rest and digest” through
the release of ACh from where?
postganglionic neurons
Slows heart rate, and increases digestive
activities
parasymp division
what is in both symp and parasymp, but stronger in parasymp
Cholinergic Synaptic Transmission
what is the neurotransmitter
used by all preganglionic neurons (sympathetic
and parasympathetic
Ach
what is also the neurotransmitter released from
most parasympathetic postganglionic neurons
Ach
some sympathetic postganglionic neurons release ACh. Where?
(those that innervate sweat glands and skeletal
muscle blood vessels)
when a neuron, receptor, or drug uses/ responds to ACh
cholinergic
2 types of cholinergic
nicotinic and muscarinic
where is cholinergic found
brain, ans, neuromuscular junction
what is the neurotransmitter
released by most sympathetic
postganglionic neurons
norepinephrine
uses/ responds to epinephrine/ norepinephrine
adrenergic
2 types of adrenergic
alpha and beta
what constricts BV and increases BP
alpha
what increases heart rate, relax airways, and boosts energy
beta
Axons of postganglionic neurons have various swellings that
release neurotransmitter along the length of
the axon
varicosities
what do varicosities form
synapses en passant
-in passing
what innervate the same tissues but release
different neurotransmitters
Sympathetic and parasympathetic neurons
where are varicosities found
in ANS, smooth muscles in BV, Intestines, Airways, and glands (sweat glands)
what do symp neurons release in varicosities
norepinephrine
what do parasymp neurons release in varicosities
acetylcholine
a neurotransmitter that directly
opens ion channels when it binds to its
receptor
ACh
what decides if the ACh is excititory or inhibitory
the organ involved
where is ACh excititory
in some areas of the CNS, in
some autonomic motor neurons, and in all
somatic motor neurons
where is ACh inhibitory
some autonomic motor neurons
-like SA node, lungs, gi tract
a messenger that carries signals between nerves and other cells (muscles, glands, brain cells)
ACh
2 types of ACh receptors
nicotinic and muscarinic
what is
-fast and direct
-stimulated by nicotine
-found on motor end plate of skeletal muscle cells, in autonomic ganglia, and some parts of CNS
nicotinic ACh receptor
what helps muscle contract
“door opens instantly”
nicotinic
where motor neuron synapse with muscle to start contraction
found on sarcolemma
motor end plate
Can be stimulated by muscarine (from poisonous mushrooms)
Found in CNS and plasma membrane of smooth
and cardiac muscles and glands innervated by
autonomic motor neurons
muscarinic
-slow and direct
-found in heart, brain, smooth muscl, glands
-mostly slows things down or stimulate smooth muscles and glands
muscarinic
uses G-protein to send a signal inside cell
muscarinic
drugs that can stimulate a
receptor
agonist
drugs that inhibit a receptor
antagonist
what is an antagonist for muscarinic
receptors.
atropine
what is an antagonist for nicotinic receptors
curare
Binding of a neurotransmitter to a receptor
can open an ion channel in one of two
ways
-ligand gated channels
-g protein coupled channels
what binds to a receptor, channel opens instantly, ions rush in
-example: nicotinic ACh receptor
ligand gated
what are ligand-gated
channels with two receptor sites for two AChs
Nicotinic ACh receptors
Binding of 2 acetylcholine molecules opens a
channel that allows what passage
both Na and K
what causes more Na + flows in
than K + out.
Due to electrochemical gradient,
what depolarizes the cell and causes EPSP
inward flow of Na
where do EPSP occur
dendrites and cell bodies
EPSPs from the binding of several ACh molecules
can be added together to produce greater
depolarization known as
graded potential
small, temporary change in the electrical charge of cells membrane.
graded potential
what may reach the threshold for voltage-gated
channels in the axon hillock, leading to action
potential
graded potentials
multiple graded potentials can add up to trigger AP
summation
slow signals. passing the signal along before making changes inside the cell
G-protein coupled channles
how does gpro work in muscarinic
ACh binds, activates gpro, opens k channels, slows heart rate
The neurotransmitter receptor is separate
from the protein that serves as the ion
channel
gprotein coupled channels
what opens ion channels
indirectly by using a G-protein
binding at the receptor
what receptors interact with ion channels with gproteins
muscarinic, dopamine, norepinephrine
what happens when g-protein bind with ACh
opens K + channels in
some tissues (IPSP) or closes K + channels in
others (EPSP).
In the heart, K + channels are opened by the
—–, creating IPSPs
(hyperpolarization) that slow the heart rate
beta-gamma complex
In the smooth muscles of the stomach, K +
channels are closed by the —
producing EPSPs (depolarization) and the
contraction of these muscles.
alpha subunit,
an enzyme that inactivates ACh
activity shortly after it binds to the receptor
AChE
Hydrolyzes ACh into acetate and choline,
which are taken back into the presynaptic cell
for reuse
AChE
what is an enzyme that breaks down ACh after it sends signal
AChE
why is AChE imp
-prevents overstimulation
-resets signal system of neurons
steps of G-protein and how they work
1) ACh (or other neurotrans) bind to receptor on cells surface
2) activates G-pro inside cell to caryy the message
3) G-pro tells ion channel what to do: open/ close ion channel, activate enzyme, trigger other cellular response
what responses Can be epinephrine in the blood or
norepinephrine from sympathetic nerves
adrenergic stimulation
which response Can stimulate or inhibit, depending on
receptors
adrenergic
examples of stimulation in adrenergic stimulation
heart, dilatory muscles of the iris,
smooth muscles of many blood vessels
(causes vessel constriction)
exazmple of inhibition in adrenergic
Inhibition: Bronchioles in lungs, other blood
vessels; inhibits contraction and causes
dilation of these structures
critical for regulating responses in stress, excitement, physical activity
-get from adrenal medulla and sympathetic
adrenergic
produced by the symp and adrenal medulla. functions in vasoconstriction, increases alertness, focus, and regulates mood
norepinephrine
produced by adrenal medulla. released into the bloostream as a hormone during stress
functions: raise heart rate and blood flow to muscles, dilates airways, boost glucose, vasoconstrict (skin/ dig) and vasodilate muscles
epinephrine
whats in nervous system and helps with mood/focus
norep
thru body and physical extention/energy
epinephrine
“active”
stimulate
“block”
inhibit
what act using G-pro and 2nd messengers in the adrenergic stimulation
alpha and beta
when adrenalin or noradrenalin bind to these receptors, they cause things to tighten (like BV)- vasoconstriction- this increases BP.
alpha 1
so stimulating these receptors help the body get more blood
alpha 1
help reduce amount of norepinephrine released. when these receptors are activated, they inhibit the release of more adrenalil/ norep.
-help calm down after excitement
alpha2
binding of nor-rep at synapse
alpha
used in the heart. when adrenalil binds, causes heart to beat fast and strong (helps pump blood during stress).
beta1
this increases heart rate and boosts heart performance
beta1
more sensitive to blood
epinephrine
beta
more sensitive to
norepinephrine
alpha
located on presynaptic axons
a2 receptors
When stimulated, result in inhibition of
norepinephrine release in the synapse
a2 receptors
May be a negative-feedback system
a2 receptors
Some drugs to lower blood pressure act on a2
receptors to
inhibit presynaptic neurons in the brain,
inhibiting the whole sympathoadrenal system
the functions of this include:
-inhibit NT release to calm down
-lower BP
-regulate insulin
-pain modulation
a2 receptor
what counterbalances to prevent excessive symp activation
a2 receptor
drugs that mimic adrenergic response
agonist and antagonist
how is ach an agonist
-on skeletal muscle= makes contract
-on heart= slows down
how is ach an antagonist
on heart= ach is blocked which leads to increase in heart rate because ach initially lowers it
ACh released from preganglionic neurons
of both the sympathetic and
parasympathetic division is
stimulitory
released to communicate with organs
ach
ACh from postganglionic neurons of the
parasympathetic division is usually
stimulatory, but some are inhibitory,
depending on
receptors
example of receptors that make binding of ach stimulatory or inhibitory
stim= ach binds to M3 in digestive to speed up
inhib= ach binds to m2 in the heart to slow down
is ach excititory or inhibitory in para.
where is this found
excititory
-smooth muscle and oculomotor
cholinergic receptors include
nicotinic and muscarinic
found in autonomic ganglia
it excited/ stimulates
nicotinic
Stimulated by Ach from preganglionic neurons
nicotinic
Serve as ligand-gated ion channels for Na + & K
nicotinic
Blocked by curare
nicotinic
what makes muscles inable to contract(paralysis) and prevents ach from binding to nicotinic
curare
what sends messages btwn nerves or to muscles
nicotinic
when ach binds to nicotinic
mucle contracts
ganglia= pass signal btwn nerves in ANS
found in visceral organs and
stimulated by release of Ach from
postganglionic neurons
muscarinic
Use G-proteins and second messenger system
muscarinic
Blocked by atropine
muscarinic
the five types of muscarinic can be
stim of inhib (opening k+ or ca2+ channels)
where are muscarinic found
heart, smooth muscle, glands
when muscarinic stimulates what happens
dig syst= help gut contract and move food
when muscarinic slows down, what happens
in the heart- slows down
in lungs- cause constriction of airways
what is the term for Some postganglionic autonomic neurons
do not release ACh or norepinephrine
nonadrenergic, noncholinergic fibers
since nonadrenergic and noncholinergic do not release ach or norep, what do they use
ATP,
vasoactive intestinal peptide (VIP), and nitric
oxide (NO)
where are nonadrenergic, noncholinergic fibers found
gut, lungs, BV to vasodilate, regulate gut movt (peristalisis), relax smooth musc
what makes the muscles contract in nonadrenergic, noncholinergic fibers
atp (excititory)
what relax airways in nonadrenergic, noncholinergic fibers
NO and VIP
Important for erection of the penis.
Nonadrenergic, Noncholinergic Fibers
why are Nonadrenergic, Noncholinergic Fibers Important for erection of the penis.
NANC release NO to make the BV dilate and fill with blood, which leads to erection
what can also produce smooth muscle
relaxation in the stomach, intestines, urinary
bladder, and the brain
nitric oxide
what innervate blood
vessels, causing relaxation and vasodilation
using NO.
parasymp neurons
what are innervated by
both sympathetic and parasympathetic
neurons
most visceral organs
which systems are antagonists
heart rate, digestive functions, pupil diameter
Occur when both divisions produce similar
effects on the same target
Complementary Effects
how is saliva production complementary effect
para= makes it watery (for dig)
symp= makes saliva thick (protection)
Occur when both divisions produce different
effects that work together to promote a single
action
cooperative effects
how is erection/ejaculation cooperative
para= erect by dilating BV (relax)
symp= ejaculate by contract muscles (tightening)
which organs are innervated by the
sympathetic division only
adrenal medulla, arrector pili muscles in skin, sweat glands in skin, most BV
the importance of the 4 organs only being innervated by symp division
Important for body temperature regulation
through blood vessels and sweat glands
what is the result of Sensory input is sent to brain centers (usually
by the vagus nerve)
integrate the
information and modify the activity of
preganglionic neurons.
what controls many
cardiovascular, pulmonary, urinary,
reproductive, and digestive functions.
medulla oblongata
what regulates the medulla
regulate the medulla
-hypo
-limbic system
-cerebellum
-frontal/temporal lobes
regulatory center of the ANS
– body temperature, hunger, thirst, pituitary gland
hypo
responsible for autonomic
responses during emotional states (blushing,
pallor, fainting, cold sweating, racing heart rate
limbic system
motion sickness nausea, sweating,
cardiovascular changes
cerebellum
emotion and personality
frontal/temporal
serious condition that
can cause stroke, pulmonary edema, and
myocardial infarction in people with spinal cord
injuries at or above the sixth thoracic level (T6) of
the spinal cord.
Autonomic dysreflexia
Associated with increased levels of
sympathetic activity
aging
Increased sympathetic tone
aging
Increased risk for hypertension and
cardiovascular diseases
aging
what transduces (change)
different forms of energy in the “real world” into nerve impulses
sensory receptors
what are examples of Sensory receptors transduce (change)
different forms of energy in the “real
world” into nerve impulses
your eyes take in light and turn it into electrical signals so your brain can see
categories of sensory receptors according to the type of signal they transduce
chemoreceptors, photoreceptors, thermoreceptors, mechanoreceptors
sense chemicals in the environment (taste,smell) or blood
chemoreceptors
what is the normal stimulus for chemoreceptors
dissolved chemicals
examples of chemoreceptors
osmoreceptors, exteroceptors, and carotid body chemoreceptors
sense light
photoreceptors
example of photo receptor
rod/cones in the retina of eye
responds to cold or heat
thermoreceptors
responds to the change in temperature
thermoreceptors
stimulated by mechanical
deformation of the receptor (touch, hearing)
mechanoreceptors
example of mechanoreceptors
cutaneous touch/ pressure receptors; vestibular apparatus and cochlea
only release when cell’s in pain.
nociceptors
normal stimulus is tissue damage
-example= cutaneous pain receptors
nociceptors
Pain receptors that depolarize when tissues are
damaged
nociceptors
Stimuli can include heat, cold, pressure, or
chemicals
nociceptors
Perception of pain can be enhanced by
emotions, concepts, and expectations.
Pain reduction depends mainly on
endogenous
opioids.
body produces naturally (insulin and focus)
endogenous
outside body. caffiene and lous noises
exogenous
Receptors can be classified by the type of
information they deliver to the brain:
proprioceptors, cutaneous receptors, special senses
found in muscles, tendons, and
joints. Provide a sense of body position and
allows fine muscle control
proprioception
your brain uses this to know where your body is. adjusts posture, balance, coordination
propriceptors
example of proprioceptors
walking without looking at your feet
what receptor deliver touch, pressure,
heat, cold, and pain to the brain
cutaneous (skin) receptors
examples of cutaneous receptors
mechanoreceptors, thermoreceptors, nociceptors
special senses
vision, hearing,taste,smell,equilibrium
Receptors can be classified by the origin of
the information:
exteroceptors and interoceptors
respond to stimuli from outside
the body; includes cutaneous receptors and
special senses
exteroceptors
respond to internal stimuli; found in
organs; monitor blood pressure, pH, and oxygen
concentrations.
interoceptors
Exteroceptors detect changes from outside
the body; include taste and smell.
-which receptor does this fall in line with
chemoreceptors
Taste responds to chemicals dissolved in
food and drink
smell responds to
chemical molecules from the air
what greatly influences gustation
olfaction
receptors are called
taste buds
consist of
50 to 100 specialized epithelial cells with
long microvilli that extend out through the
pore in the taste bud to the environment of
the mouth
taste buds
why do we have microvilli on our tongue
essential for detecting taste molecules and transmit the info to your brain
why are taste cells of taste buds epithelial cells
cells behave like neurons by depolarizing and producing AP, release NT onto sensory neurons, microvilli come into contact with chemicals.
Each taste bud has taste cells sensitive to
each category of tastes. why?
can taste all 5 tastes, but brain receives different sensitivity
5 categories of taste
salty, sour, sweet, umami, bitter
how to taste buds act like cells
-detect stimuli
-convert chem signals into electrical signals
-comm with nerves
-regenrate/replace old cells
which molecule responds to salty
Na
which molecule responds to sour
H
which molecule responds to sweets
sugar (glucose and monocarbohydrates)
what molecule responds to umami
glutamate
which molecule responds to bitter
quinine
true/false: all
regions of the tongue have taste buds for all the
categories
true
influenced by the temperature and texture of
the substance
taste
when temp increases, what happens to the membrane permeability
becomes more perm (loose)
when temp decreases, what happens to the membrane permeability
decrease dissusion
Smell is also called
olfaction
responsible for sense of smell. detects airborne molecules and sends signals to the brain, allowing us to recognize and detect odors
olfactory apparatus
Olfactory receptors are located in the
olfactory epithelium of the nasal cavity.
what do sustentacular cells do
oxidize hydrophobic volatile odors
-help modify so olfactory can detect
means that supporting cells in the nose help break down strong smelling, oily odor molecules
Sustentacular cells oxidize hydrophobic
volatile odors
chemically modify molecules to make detection easy
oxidize
easily turn to gas (what we inhale)
-gas, perfume, oils
volatile
what cells replace receptors damaged
by the environment
basal stem
provides a sense of equilibrium, located in inner ear
vestibular apparatus
consists of utricle, saccule, and semicircular canals
vestibular apparatus
3 canals of semicircular canals
anterior canal, posterior canal, lateral canal
sensory structures that help process different types of movt
macula and cupula
inside utricle and saccule. detect linear acceleration (going up an elevator)
macula
in crista ampullaris. detects rotational motion
cupula
Consists of a bony labyrinth surrounding a
membranous labyrinth
inner ear
the inner ear contains 2 fluids that help with hearing and balance by facilitating the transmission of mechanical signals to sensory cells
perilymph and endolymph
found in bony labyrinth and surrounding memb labyrinth.
-functions in transmitting sound and structural support
perilymph
Within the membranous labyrinth
-functions in stimulating hair cells for hearing and balance
endolymph
in the inner ear. converts mechanical energy to electrical signals
sensory hair cells
Modified epithelial cells with 20 to 50 hairlike
extensions called stereocilia (not true cilia) and
one kinocilium (true cilium)
sensory hair cells
detects mechanical movt and open ion channels. located in cochlear and vestibular hair cells. respond to bending
stereocilia
provides directional difference for movt. located in vestibular hair cells. respond to movt toward kinocilium=excititory. away=inhibitory
kinocilium
horizontal
utricle
verticle
saccule
specialized epithelium that houses hair cells
macula
are embedded in a gelatinous
otolithic membrane
stereocilia
The gel also contains crystals of calcium
carbonate called
otoliths (ear stones)
in semicircular canals, there are three planes to detect rotation:
endolymph, ampulla, crista ampullaris
Each canal contains a semicircular duct
filled with
endolymph
At the base of each duct is an enlarged area
called the
ampulla
what houses crista ampullaris
ampulla
Hair cells are embedded in the
crista ampullaris
Hair cells are embedded in the crista
ampullaris, with stereocilia stuck into a
gelatinous cupula
aka the sensory organ of ampulla. located inside amoulla. detects angular acceleration and sends signals to vestibular nerve
crista ampullaris
sits on top of crista ampullaris covering hair cells. moves in response to endolymph fluid displacement and sends balance signals.
gelatinous capula
what makes the endolymph circulate,
pushing the cupula and bending the hair cells
rotation
what nerve synapses in
the vestibular nuclei of the medulla and in
the cerebellum
vestibulocochlear nerve
what sends neurons to the
oculomotor area of the brain stem to
control eye movements and down the
spinal cord to adjust body movements
medulla
When a person’s body is spinning, what happens to eyes
eye movements
are toward the opposite direction of the spin to
maintain a fixation point
When the body comes to a stop after spinning, what happens
the cupula is bent
by fluid inertia and eye movements are still affected
The jerky eye movement produced is called
nystagmus
can cause a loss of equilibrium called
vertigo
nystagmus
funneled by the pinna
(or auricle) into the external auditory
meatus, which channels them to the
tympanic membrane (eardrum)
sound waves
located on outer part of ear. made up of cartilage and skin with curves. functions in collecting and amplifying sound waves from environment and directs sound to external aud meautus
pinna (auricle)
acts as a resonating tube. amplifying sound frequencies for speech and recognition. protects tympanic memb by filtering dust. debris, and insects thru cerumen production
external aud meatus (ear canal)
semi transparent memb at the end of external aud meatus seperating the outer and middle ear. vibrates in response to sound waves. transmits these vibrations to ossicles for further sound processing.
tymanic memb (eardrum)
Air-filled cavity between the tympanic
membrane and the cochlea
middle ear
what are the three bones in middle ear (called ossicles)
malleus, incus, and stapes
what happens in the ossicles regarding vibrations
Vibrations are transmitted and amplified along
the bones
The stapes is attached to the
oval window
transfers the vibrations into the cochlea
oval window
dampens the stapes if the
sound is too intense
stapedius muscle
attached to tympanic memb and connected to incus. receives vibrations from eardrum and pass to incus
malleus
in btwn malleous and stapes. acts as a bridge transmitting vibrations from malleus to stapes
incus
smallest bone in the body. connected to oval window. transfers vibrations from incus to oval window creating fluid movt in cochlea
stapes
help amplify sound waves as enter cochlea
oval window
protect inner ear from loud noises.
-if paralyzed- bells palsy, leads to hyperacusis where normal sounds seem very loud
stapedius muscle
pathway of light
-corneal
-anterior chamber
-pupil
-posterior chamber and vitreous body
-lens
-retina
can cause change shape to allow more or less light in
pupil
what causes the pupil to change shape
the pigmented iris muscle
multilayered tissue. refracts light, protects eye.
cornea
fluid filled chamber. maintains intraocular pressure, nourish cornea and lens. aqueous humor
anterior chamber
filled with aqueous humor. produce and circulate aqueous humor, maintain intraocular pressure
posterior channel
filles with gel like fluid. maintain eye shape, support retina, allow light transmission
vitreous body
change shape to focus on image
lens
where
photoreceptors are found and then absorbed
by the pigmented choroid layer
retina
can increase or decrease the
diameter of the pupil
the iris
contraction of circular muscles via
parasympathetic stimulation
constriction
contraction of radial muscles via
sympathetic stimulation
dilation
why does the iris have pigmented epithelium
for eye color
Composed of layers of living cells that are
normally completely clear
lens
The lens is —. causes cataracts or presbyopia
avascular
no blood vessels. critical for maintaining transparency and optimal light trasnsmission to retina
avascular
Cell metabolism is very
low and anaerobic
why is the cell metabolism low and anaerobic
-avascular nature
-relies on anaerobic for energy bc limited oxygen supply
lens are Attached to muscles called
ciliary bodies
what are Suspended from suspensory ligaments
lens
control lens shape for focus. contract and relax to adjust shape
ciliary muscles
sttatch the lens to ciliary body to adjust focus
suspensory ligs
Fills anterior and posterior chambers
aqueous humor
A clear, watery liquid secreted by ciliary
bodies to provide nourishment to lens and
cornea
aqueous humor
Drains into scleral venous sinus (Canal of
Schlemm) back into the blood
aqueous humor
Inadequate drainage of aqueous humor leads to
glaucoma
circular drainage channel in eye that plays role in removing aqueous humor and maintain intraocular pressure
scleral venous sinus (canal of schlemm)
what is the result of blocked schelmm canal
glaucomma
the part of the external world
projected onto the retina
visual fields
why is each visual field projected onto the opposite side of retina
due to the way light enters the eye
in the right eye, light enters onto the
nasal retina (medial)
in the left eye, light enters into
temporal retina (lateral)
what does the crossover in the retina ensure
both eyes contribute to binocular vision and depth perception
a forward extension of the
brain, so the neural layers face outward
toward the incoming light
retina
Neuron axons in the retina are gathered
at a point called— and exit as the optic nerve
optic disc (blind spot)
what also enter/ leave optic disc
blood vessels
a light sensitive layer at the back of the eye responsible for detecting visual info and transmitting into the brain
retina
contains photoreceptors- convert light to electrical signals
retina
important layers of retina
photoreceptors, bipolar cells, gang cells
recieve inout from bipolar cells and sends signals thru axons which form the optic nerve
gang cells
the point where gang cells converge to form the optic nerve
optic disc (blind spot)
key regions of retina
fovea centralis, macula, optic disc
surrounds the fovea and important for detailed vision
macula
allow back and white vision in low light
rods
contain the purple pigment and absorbs green light best
rhodospin
photopigment found in rod cells in retina. responsible for detecting dim light and enabling high vision
rhodospin
called bleaching reaction
rhodospin
prevents overstimulation of rods in bright lights and explains why temporary blindness when move from bright to dark env
bleaching reaction/ rhodospin
during dark adaptation, what happens after 20 mins of being in the dark
more visual
pigments are produced, and the person’s
eyes adapt to the dark.
When a person enters a dark room after
being in the light:
there are fewer
photopigments in the rods and cones
Vision is best at one point in the retina, called the
—- within the macula lutea
fovea centralis
in the fovea centralis, other layers of the retina are pushed aside. what happens
light falls directly on a group of cones
what allows great visual activity in the fovea centralis
Each cone has a 1:1 relationship with a ganglion cell
what only works in good light
fovea centralis
Convergence of lots of rods onto a single
ganglion cell increases
light sensitivity
continually shift parts
of the visual field onto the fovea
saccadic eye movt
rapid eye movt that shifts focus from 1 point to another.
-ex=reading
saccadic eye movt
ductless, secretes hormones into the blood
endocrine glands
how are hormones are carried to target cells having receptors for those hormones
endocrine glands
what organs secrete hormones
heart, liver,
kidneys, and adipose tissue
are secreted by specialized
cells of the hypothalamus
neurohormones
what do hormones help regulate
body metabolism,
growth, and reproduction
the chemical classification of hormones
amine, peptide, proteins, steroids
derived from tyrosine and tryptophan
amine
examples of amines
hormones from the adrenal
medulla, thyroid, and pineal glands
what hormone is a single amino acid
amine
can be water soluble or fat soluble- depends on hormone
amine
catecholamines (epi and norep), thyroid hormones, melatonin
amines
any chemical reaction
metabolism
constructive; supports growth, repair, storage of energy. consumes atp.
ex- protein synthesis and dna replication
anabolism
destructive; breakdown complex molecules. provides energy for cellular activity. produces atp
example- digestion, glycolysis, lipolysis
catabolism
building blocks of proteins. they are hydrophilic and cant pass thru the cell membrane, so they bind to receptor on cell surface to trigger 2nd messenger.
polypeptides and proteins
examples of polypeptides and proteins
antidiuretic hormone, insulin, and
growth hormone
long polypeptides bound to carbohydrates. water soluble and bind to receptors on surface of target cell.
glycoproteins
examples of glycoproteins
follicle-stimulating and luteinizing
hormones
regulates the reproductive process like dev of eggs and sperm
-made up of alpha and beta
follicle stimulating
involved in ovulation and producing sex hormones
lutenizing hormones
lipids derived from cholesterol
steroids
examples of steroids
testosterone, estradiol,
progesterone, cortisol
what are steroids secreted by
adrenal cortex and gonads
fat soluble, can easily pass. receptors inside cell (in cyto or nucleus)
steroids
stress hormone
cortisol
polar hormones are
water soluble and cant pass thru memb
what must be injected if used as drug? what must be taken orally
polar hormones; nonpolar
polar hormones include
polypeptides, glycoproteins,
norepinephrine, and epinephrine
insoluble in water, can enter target cells
nonpolar
lipophilic hormones are
nonpolar
usually fast and short lived
polar
transported by carrier proteins
nonpolar
include steroids, thyroid hormone, and melatonin
nonpolar
Hormones and neurotransmitters both interact
with
specific receptors
binding to a receptor causes change where
within the cell
how do the nerv sys and endo sys rely on chemical messengers to communicate
nerve= NT released on synapse (muscle/glands)
endo= hormones released into bloodstream by glands to travel to target organ/tissue
how does binding to a cell cause change in cell in nerve and endo sys
nerve= NT depolar or hyperpolar
endo= gene expression, enzyme activation, and metabolic changes
There are mechanisms to turn off target cell activity; the signal is either removed or inactivated. what does the nerve and endo sys do
nerve= NT. reuptake, enzymatic breakdown, diffusion
endo= horm. breakdown by enzymes
Neurotransmitters and hormones have many
similarities including
chemical nature, receptor interaction, regulation
Some hormones can also be neurotransmitters
in the CNS, including
epinephrine.
-in cns, mood attention and alert
-in horm, regulate heart, blood flow, and metabolism
a target cell is usually responsive to
several different hormones
hormones may be
antagonistic, synergistic,
or permissive
How a cell responds depends on
the amount
of hormone and the combination of all
hormones
Occur when two or more hormones work
together to produce a particular effect
synergistic
effects may be additive, meaning, their combined effect is greater than if each hormone acted alone
synergistic
Effects may be complementary, as when
each hormone contributes a different piece
of an overall outcome
synergistic
example of synergistic effects
-producing milk requires estrogen, prolactin, and oxytocin
-FSH from pit gland and estrogen from ovary are required for maturation of egg cells
one hormone enables another hormone to act
permissive
Exposure to estrogen makes the uterus
more responsive to progesterone
permissive
Occur when hormones work in opposite
directions
antagonistic
what are the effects of hormone concentrations on tissue response
hormone half life, hormone concentration, up and down regulation
refers to the time it takes for half of the hormones concentration in the blood stream to degrade or remove from body.
-how fast/ slow body responds to changes in hormone levels
hormone half life
what has shorter half life because theyre broken down quickly by enzymes in blood stream
peptides
have longer half life bc theyre more stable in bloodstream
steroid and thyroid
Tissues only respond when hormone
concentrations are at a certain “normal” or
physiological level
hormone concentration
Some target cells respond to a particular
hormone by increasing the number of
receptors it has for that hormone
priming effect/ upregulation
This makes it more sensitive to subsequent
hormone release and have a greater
response
upregulation
when the level of hormones reduce, target cells try to increase the number of receptors and allow cells to alter sensitivity of receptors to various hormones
upregulation
Prolonged exposure to high concentrations
of hormone may result in a decreased
number of receptors for that hormone
desensitization and downregulation
Occurs in adipose cells in response to high
concentrations of insulin
downregulation
To avoid desensitization, many hormones
are released in spurts, called
pulsatile secretion
when presence of a significant level of hormone circulating in bloodstream can cause its target cell to decrease the number of receptors for that hormone.
-allows cell to become less reactive to the excessive hormm levels
desensitization/ down regulation
where do hormones bind to receptors
on or in target cells
how do hormones bind to receptors
-highly specific
-high affinity
-bind to receptors with low capacity; saturating rec with hormone molecules
strongly binds even if present in low concentrations.
high affinity
the point at which all available receptors are fully occupied or bound by their respective ligands
saturation
which hormone receptors are in the
cytoplasm or nucleus
lipophilic
which hormone receptors are on the
outer surface of the plasma membrane
water soluble
intracellular proteins that function in transcription factors, regulate gene expression in response to specific signaling molecules. these receptors are located inside the cell and activated by hormones that CAN CROSS MEMB
nuclear receptor proteins
what hormone can bind to nuclear receptor protein
lipophilic steroid hormone
Travel to target cells attached to carrier
proteins
lipophilic steroid horm
what happens to lipophilic steroid horm when it reaches target cell
At the target cell, dissociate from the carrier
protein and diffuse across the plasma
membrane
Receptors are found within the nucleus and
are called
nuclear hormone receptors
why are receptors found in nucleus called nuclear horm rec
they activate genetic transcription
make rna
transcription
binding to dna
genetic transcription
first step in making a protein. It’s the process where your DNA (genetic code) is copied into a message called mRNA (messenger RNA). This message is then used to build proteins,
transcription
serve as transcription factors because they enter cell, bind to dna, and activate/ change gene expression
steroid hormones
activated by the binding of hormone
NHR
The effect of these hormones is therefore to
produce new proteins, usually enzymes that
change metabolism inside the cell.
steroid hormones
type of intracellular receptor that acts as transcription factors when activated by lipid-soluble hormones
nuclear hormone receptor (NHR)
2 regions of NHR
lipid binding and dna binding
binds to hormone, causes receptor to undergo a change that activates its transcriptional reg function
ligand binding domain
binds to specific sequences of dna known as hormone response element (HRE)
dna binding domain
binding of the hormone activates the
dna binding domain
binds to a hormone response element on the dna
dna binding domain
is a
short DNA span adjacent to the gene that will
be transcribed
HRE
two main families in NHR
steroid and thyroid
include receptors that are activated by steroid hormones and other lipophilic signals. located in cyto and translocate to nucleus upon activation.
-leads to dimerization and dna binding to regulate transcription
steroid family
activated by thyroid hormone and located in nucleus. does not require translocation after ligand binding.
-involved with metabolism and develoipment
thyroid family
mechanisms of steroid hormone action
nongenomic and genomic
involve rapid cell response that does not require change in gene expression. usually signal transduction pathways that rapidly alter cell activity with out affecting gene transcription.
nongenomic
May occur in the cytoplasm and involve
second-messenger systems
nongenomic
activate already existing enzymes/ proteins
nongenomic
an example is steroid hormone acting thru memb-bound receptors or GCPR
nongenomic
lipid soluble; where transcription actually occurs
genomic
involves changes in gene expression. this is slow and results in production of new proteins.
-ex= steroid/thyroid horm
genomic
once the hormone binds to receptor, the complex translocates to the nucleus.
genomic
Hormone-receptor complex binds to
the specific
hormone-response element of DNA
what does it mean for hormones to have 2 half sites
2 ligand bound receptors must bind
what is it called when 2 ligand bound receptors bind
dimerization
what does dimerization form
homodimer- because both complexes are the same
what happens when dimerization occurs
The activated nuclear hormone receptor now
stimulates transcription
enhance and activate gene transcription. increase effects of hormone
coactivators
repress and inhibit gene transcription
corepressors
proteins that modulate the transcriptional activity of NHR after they bind to their HRE in DNA
coactivators and corepressors
Molecules that are needed in addition to the
steroid hormone
Coactivators and Corepressors
They bind to the nuclear receptor proteins at
specific regions
Coactivators and Corepressors
This changes the effect of a given hormone
in different cells; may activate or suppress
transcription factors
Coactivators and Corepressors
hormones that use 2nd messengers cannot..
These hormones cannot cross the plasma
membrane, so they bind to receptors on the
cell surface
intracellular mediator
second messenger
3 possible 2nd messengers:
a. Adenylate cyclase
b. Phospholipase C
c. Tyrosine kinase
enzyme that converts ATP to cAMP. it amplifies signa, and activates PKA to regulate metabolic processes, gene exp, and ion channels
adenylate cyclase (cAMP)
generates calcium release from intracellular stores and activates PKC
phospholipase C
activates intracellular signaling cascades that regulate cell growth, survival, differentiate, and metabolism
tyrosine kinase
Used by epinephrine and norepinephrine
camp
Binds to a β-adrenergic receptor
camp
attached to the
hypothalamus by the infundibulum
pituitary gland
the pituitary gland is divided into anterior and posterior lobe, or also known as
adenohypophysis (AL) and neurohypophysis (PL)
The anterior pituitary is glandular
epithelium with two parts
pars distalis and pars tuberalis
largest. main site of hormone production and secretion
pars distalis
wraps around infundibulum. hormone regulated to light cycles and cardian rhythms
pars tuberalis
found in fetus only
pars intermedia
The posterior pituitary is nervous tissue
and also called
pars nervosa
neurohypothesis. store and release hormones produced by hypothalamus (oxy and adh)
pars nervosa
secreted by the ant lobe
pituitary hormones
what hormones stimulate hormone secretion in other glands. growth/ nourishment of target tissues
trophic
what hormones target other endo glands to stimulate hormone release
tropic
6 hormones in ant lobe
growth hormone
thyroid-stim horm
adrenocorticotropic horm
follicle stim horm
luteinizing horm / interstitial cell stim horm
prolactin
which ant lobe hormones are trophic
growth horm and prolactin
which ant lobe hormone is tropic
thyroid stimulating horm
adrenocorticotropic horm
luteinizing horm/ interstitial cell stim horm
follicle stim horm
stores and releases two hormones made in hypo
post pit horm
what are the 2 horm made in hypo
antidiuretic horm
oxytocin
promotes the retention
of water in the kidneys. functions in water balance and maintain bp. NFL
antidiuretic hormone
stimulated by increase Blood osmolarity (dehydration), decrease blood volume/ BP
ADH
stimulates
contractions in childbirth and
milk let-down in lactation
oxytocin
produced by the
supraoptic and paraventricular nuclei
of the hypothalamus
antidiuretic horm and oxytocin
located above optic chiasm and functions in synthesizing antidiuretic horm.
supraoptic
near 3rd ventricle. produces oxytocin anf synthesizes antidiuretic horm. utering contraction, milk ejection, stress response, and metabolism regulation
paraventricular nuclei
how to antidiuretic horm and oxytocin get transported along the axon to post pituitary where they are stored
hypothalamohypophyseal tract
connect the hypothalamus and posterior pituitary gland. transports and release hormone production by hypothalamus, specifically ADH and oxytocin
hypothalamohypophyseal tract
Release is controlled by
neuroendocrine reflexes
nerv system and endo syst work together to control/ regulate body function involving sensory input
neuroendocrine reflexes
ADH is stimulated by
increase in blood osmolarity (dehydration)
how is oxytocin stimulated
suckling
releasing and
inhibiting hormones
transported through
the
hypothalamohypo
physeal portal
system controls what?
the anterior pit
what are the 6 releasing and inhibiting hormones in ant pit
corticotropin rel horm
gonadotropin rel horm
prolactin inhib horm (dopamine)
somatostatin (growth horm inhib horm)
thyrotropin rel horm
growth horm rel horm
Stimulates secretion of
adrenocorticotropic hormone
(ACTH
corticotropin rel horm
Stimulates secretion of
follicle-stimulating hormone (FHS)
and luteinizing hormone (LH
gonadotropin rel horm
Inhibits prolactin secretion
prolactin inhib horm (dopamine)
Stimulates secretion of
thyroid-stimulating hormone (TSH
thyrotropin rel horm
stim growth hormones
growth horm rel horm
The final product regulates secretion of pituitary
hormones
NFL
relationship between the hypothalamus,
anterior pituitary, and the target tissue is called
axis
what does inhibition and pit gland level cause in hypothalamic horm
inhibiting response
what does inhibition at hypothalamic level cause
inhibiting secretion of releasing hormones
Found superior to the kidneys
adrenal glands
what do the adrenal glands consist of
adrenal cortex (outer) and adrenal medulla (inner)
neural tissue and
secretes epinephrine and norepinephrine in
response to sympathetic neural stimulation
adrenal medulla
produces catecholamines
adrenal medulla
glandular epithelium
and secretes steroid hormones in response to
ACTH
adrenal cortex
what hormones do adrenal cortex produce
steroid- cortisol, aldosterone, androgens
3 layers of adrenal cortex
zona glomerulosa, zona fasciculata, and zona reticularis
outer layer. produces aldosterone to regulate sodium and water balance
zona glomerulosa
middle layer. produces cortisol
zona fasciculata
inner layer. produces androgens- influence sex dev and func
zona reticularis
adrenal cortex function:
Secretes hormones made from cholesterol, mineralocorticoids, and glucocorticoids
howmones made from cholesterol
corticosteroids
from the zona glomerulosa
regulate Na + and K + balance
ex- aldosterone
mineralocorticoids
from the zona fasciculata
regulate glucose metabolism
-ex= cortisol
glucocorticoids
from the zona reticularis are
weak sex hormones that supplement those made
in the gonads
adrenal androgens
