Transcript Action Potentials, Muscle Contraction, and Animal Behavior

Chapter 28: Nervous Systems
NEW AIM: What types of nervous systems have evolved among animals?
I. Nervous Systems
A. Most intricately organized data processing system on Earth
B. Neurons
i. Nerve cells specialized for carrying signals from one location to
another (cellular wires)
ii. 50,000,000 per cm3 in your brain
iii. A single neuron may communicate with 1,000 others
Chapter 28: Nervous Systems
NEW AIM: What types of nervous systems have evolved among animals?
I. Nervous Systems
A. Most intricately organized data processing system on Earth
B. Neurons
i. Nerve cells specialized for carrying signals from one location to
another (cellular wires)
ii. 50,000,000 per cm3 in your brain
iii. A single neuron may communicate with 1,000 others
Chapter 28: Nervous Systems
NEW AIM: What types of nervous systems have evolved among animals?
I. Nervous Systems
A. Most intricately organized data processing system on Earth
B. Neurons
Central Nervous System (CNS)
- Brain and spinal cord –
interneurons and supporting cells
- Along the central plane of
the body
Peripheral Nervous System (PNS)
- Peripheral means out to the
sides
- Sensory neurons, motor
neurons and supporting cells
Fig. 28.1
Chapter 28: Nervous Systems
NEW AIM: What types of nervous systems have evolved among animals?
I. Nervous Systems
A. Most intricately organized data processing system on Earth
B. Neurons
i. Three general types
1. Sensory neurons
- conduct signals FROM sensory receptors to integration centers
(brain/spinal cord – CNS)
Sensory receptors (special cells that convert a stimulus into an
electrical signal):
a. Pain receptors (nociceptors)
b. Thermoreceptors – sense temperature change
c. Mechanoreceptors – sense touch, hearing (vibrations in air)
d. Chemoreceptors – taste buds
e. Electromagnetic receptors – rod (grey scale) and cone
(color) cells of eye
Chapter 28: Nervous Systems
NEW AIM: What types of nervous systems have evolved among animals?
I. Nervous Systems
Figure of the skin showing
neurons involved in sensing
temperature (thermoreceptor),
pain (nociceptor), light touch,
deep pressure, and touching
of hair (mechanoreceptors).
Chapter 28: Nervous Systems
NEW AIM: What types of nervous systems have evolved among animals?
I. Nervous Systems
Figure showing “hair” receptor cells found in the ear (organ of Corti). The “hairs” are actually specialized cilia
called stereocilia. The cilia will vibrate back and forth. When they bend to the right, they release a chemical signal
called a neurotransmitter, which activates the neuron and sends a signal to the brain (mechanoreceptors).
Chapter 28: Nervous Systems
NEW AIM: What types of nervous systems have evolved among animals?
I. Nervous Systems
Electromagnetic receptors
Rod and cone cells are found on
the retina (the photographic film of
the eye). Rod cells convey
electrical signals to the brain,
which interprets the signals as
shades of grey, while cone cells
convey electrical signals down the
optic nerves to the a part of the
brain that interprets them into
color vision.
Chapter 28: Nervous Systems
NEW AIM: What types of nervous systems have evolved among animals?
I. Nervous Systems
chemoreceptors
Taste buds on the tongue are collections of chemoreceptor cells with assorted
protein receptors on their surfaces for all sorts of different molecules. When a
ligand (ex. Sucrose) binds to the receptors, the receptor opens (it’s a ligand
gated channel) causing a signal to be sent through the cell and neurotransmitter
to be released, which activates the sensory neurons sending an electrical signal
to your brain that is interpreted as the taste of sucrose. What would you taste if I
swapped these sensory cells with ones that bind to molecules in a lemon? You
would still taste sucrose (sweet) because they are connected to the same
neurons and the signal goes to the same part of the brain. In fact, if I connected
these neurons to your skin mechanoreceptors, every time I touch your skin you
would taste sweetness!!! Think about this!!
Chapter 28: Nervous Systems
NEW AIM: What types of nervous systems have evolved among animals?
I. Nervous Systems
chemoreceptors
The nose also has chemoreceptor cells that work in a
similar fashion to the taste buds, but of course the
neurons go to a different part of the brain. What if I
took the neurons from the nose that are activated
when you small cabbage and connect them to your
taste buds? What would happen when you eat
something?...you would smell cabbage.
Chapter 28: Nervous Systems
NEW AIM: What types of nervous systems have evolved among animals?
I. Nervous Systems
A. Most intricately organized data processing system on Earth
B. Neurons
i. Three general types
2. Motor neurons
- conduct a signal from integration center (spinal cord/brain) to
an EFFECTOR (that which is effected and performs the
response) like muscle cells or gland cells of the adrenal medulla.
3. Interneurons (Integration neurons)
- Interpret the signal and formulate a response (spinal cord and brain)
Chapter 28: Nervous Systems
NEW AIM: What types of nervous systems have evolved among animals?
I. Nervous Systems
A. Most intricately organized data processing system on Earth
B. Neurons
C. Two main divisions of the NS
1. Central Nervous System (CNS)
- site of most integration
- brain and spinal cord in vertebrates
2. Peripheral Nervous System (PNS)
- nerves that carry signals to and from CNS
- Nerves
i. Bundles of neurons (a nerve cell) wrapped in connective tissue
- Ganglia
i. Clusters of neuron cell bodies in nerves
Chapter 28: Nervous Systems
NEW AIM: What types of nervous systems have evolved among animals?
I. Nervous Systems
A. Most intricately organized data processing system on Earth
This wire on the left would symbolize a nerve. It is not one wire, but many
wires wrapped together. The blue plastic would be connective tissue. If you
cut a nerve, you will lose the function of whatever those millions of neurons
attached to.
Chapter 28: Nervous Systems
NEW AIM: What types of nervous systems have evolved among animals?
I. Nervous Systems
All your Brain receives
are electrical pulses
Everything you observe, what
you are “seeing” right now is
being imagined by your brain
based on sensory data.
Fig. 28.11
Chapter 28: Nervous Systems
NEW AIM: What types of nervous systems have evolved among animals?
I. Nervous Systems
http://msjensen.cehd.umn.edu/1135/Links/Animations/Flash/0016-swf_reflex_arc.swf
A. Most intricately organized data processing system on Earth
B. Neurons - sensory, inter, motor
C. Two main divisions of the NS - CNS, PNS
D. The Knee Jerk Reflex (simple reflex)
1. Tap knee
2. Mechanoreceptors (sensor) detect
stretch in muscle and a signal is
conveyed to CNS (spinal cord) via
sensory neurons…
3. …directly to motor neurons, which
send the signal to contract the quads
4. …and to interneurons, which bridges
to motor neurons to inhibit contraction
of hamstrings
http://msjensen.cehd.umn.edu/1135/Links/Animations/Flash/0016-swf_reflex_arc.swf
Fig. 28.1
Chapter 28: Nervous Systems
NEW AIM: What types of nervous systems have evolved among animals?
I. Nervous Systems
A. Most intricately organized data processing system on Earth
B. Neurons - sensory, inter, motor
C. Two main divisions of the NS - CNS, PNS
D. The Knee Jerk Reflex
Be able to Label:
1. Tap knee
2. Mechanoreceptors (sensor) detect
stretch in muscle and a signal is
conveyed to CNS (spinal cord) via
sensory neurons…
3. …directly to motor neurons, which
send the signal to contract the quads
4. …and to interneurons, which bridges
to motor neurons to inhibit contraction
of hamstrings
Fig. 28.1
Chapter 28: Nervous Systems
NEW AIM: What types of nervous systems have evolved among animals?
I. Nervous Systems
E. The representative neuron…the motor neuron:
Fig. 28.2
Chapter 28: Nervous Systems
NEW AIM: What types of nervous systems have evolved among animals?
I. Nervous Systems
E. The representative neuron…the motor neuron:
Fig. 28.2
1. Cell Body
a. houses nucleus and other
organelles
2. Neuron Fibers (2 types)
a. dendrites
- extend from cell body
- short, numerous, highly
branched
- receive INCOMING messages from sensory or interneurons and send
them TO cell body
Chapter 28: Nervous Systems
NEW AIM: What types of nervous systems have evolved among animals?
I. Nervous Systems
E. The representative neuron…the motor neuron:
1. Cell Body
a. houses nucleus and other
organelles
2. Neuron Fibers (2 types)
b. axon
- usually a single fiber
- conducts signal TOWARD
another neuron or effector cell
- can by VERY long (lower part of spinal cord to toes)
- terminates in a cluster of branches (100’s to 1000’s)
i. Synaptic knobs
- on end of EACH branch
- relays signal to next neuron or effector
Fig. 28.2
Chapter 28: Nervous Systems
NEW AIM: What types of nervous systems have evolved among animals?
I. Nervous Systems
E. The representative neuron…the motor neuron:
Neurons come in different shapes and sizes
Chapter 28: Nervous Systems
NEW AIM: What types of nervous systems have evolved among animals?
I. Nervous Systems
F. Supporting cells
1. Outnumber neurons 50 to 1 in NS
2. Protect, insult, nourish neurons
a. Ex. Schwann cells
- form the myelin* sheath around
rapid transmission neurons
*myelin = electrically-insulating
phospholipid-rich layer (80%
phospholipid, 20% protein) – prevents
sodium signal from leaking
- wrap the axon like tape
around a hockey stick
Fig. 28.2
Chapter 28: Nervous Systems
NEW AIM: What types of nervous systems have evolved among animals?
*myelin = electrically-insulating dielectric
phospholipid layer (80% phospholipid,
20% protein)
I. Nervous Systems
F. Supporting cells
1. Outnumber neurons 50 to 1 in NS
2. Protect, insult, nourish neurons
a. Ex. Schwann cells
- form the myelin* sheath around
rapid transmission neurons
- wrap the axon like tape
around a hockey stick
neuron
Schwann cell
Cross section of a neuron axon
with a schwann cell wrapped
around it.
Chapter 28: Nervous Systems
NEW AIM: What types of nervous systems have evolved among animals?
I. Nervous Systems
F. Supporting cells
*myelin = electrically-insulating dielectric
phospholipid layer (80% phospholipid,
20% protein)
Fig. 28.2
1. Outnumber neurons 50 to 1 in NS
2. Protect, insult, nourish neurons
a. Ex. Schwann cells
- form the myelin* sheath around
rapid transmission neurons
- wrap the axon like tape
around a hockey stick
- Nodes of Ranvier
i. Spaces b/w Schwann cells along the axon
ii. Only space where signal can come in or leave
iii. Saltatory conduction = Signal jumps from node to node at
150 m/s or 330 miles/hour - without myelin = 5 m/s
- Multiple Sclerosis (MS)
i. Autoimmune disease against Schwann cells
Chapter 28: Nervous Systems
NEW AIM: What types of nervous systems have evolved among animals?
I. Nervous Systems
F. Supporting cells
1. Outnumber neurons 50 to 1 in NS
2. Protect, insult, nourish neurons
*myelin = electrically-insulating dielectric
phospholipid layer (80% phospholipid,
20% protein)
Fig. 28.2
Chapter 28: Nervous Systems
NEW AIM: How do neurons transmit signals?
I. Nervous Systems
G. Nerve Signals and their transmission
1. Resting neurons have potential energy:
Fig. 28.3
Chapter 28: Nervous Systems
AIM: How do neurons transmit signals?
I. Nervous Systems
G. Nerve Signals and their transmission
1. Resting neurons have potential energy:
Fig. 28.3
i. Electrical charge difference across PM
ii. Cytoplasm slightly negative relative to IF
iii. Resting potential
- Voltage across PM at rest = -70mV
- mV = milliVolts
- Volts describe the affinity for a charged
particle or the potential to move
IF = interstitial fluid
Chapter 28: Nervous Systems
AIM: How do neurons transmit signals?
I. Nervous Systems
G. Nerve Signals and their transmission
1. Resting neurons have potential energy:
iv. What generates the resting potential?
http://bcs.whfreeman.com/thelifewire/content/chp44/4401s.swf
Fig. 28.3
Chapter 28: Nervous Systems
AIM: How do neurons transmit signals?
I. Nervous Systems
G. Nerve Signals and their transmission
1. Resting neurons have potential energy:
iv. What generates the resting potential?
- proteins in cell tend to be negative
- sodium-potassium pumps
a. Use ATP to pump 3 Na+ out for
every 2 K+ in (more + out than in)
- Na+ is not allowed back in (channels are SHUT)
- What about K+?
Fig. 28.3
- K+ channels are open
- K+ allowed to diffuse down concentration gradient
- cell becomes more negative inside (positive K+ leaving)
-K+ diffuses out until electromagnetic force pulling it back equals tendency
to diffuse (EM in = diffusion out) - see the video below
Chapter 28: Nervous Systems
AIM: How do neurons transmit signals?
I. Nervous Systems
The Action Potential
(The all or nothing nerve impulse - aka electrical signal that
moves from dendrites to axon)
Action
Potential
Chapter 28: Nervous Systems
AIM: How do neurons transmit signals?
I. Nervous Systems
G. Nerve Signals and their transmission
2. Nerve signals begin with a change in membrane potential
a. Stimulus
- any factor that causes a nerve signal to be generated like
touching your skin and activating a mechanoreceptor or a
sucrose molecule binding to a receptor cell on your taste bud,
etc…
b. The Action Potential (a nerve impulse)
- wave of voltage that travels along the
membrane
- it is ALL or NOTHING (a neuron either
fires or it doesn’t)
*you send a signal from dendrite to
synaptic knob or you don’t
- They are all the same strength –
there is no such thing as a strong action potential or a
weak one…
http://highered.mcgraw-hill.com/olc/dl/120107/bio_d.swf
Chapter 28: Nervous Systems
AIM: How do neurons transmit signals?
I. Nervous Systems
G. Nerve Signals and their transmission
2. Nerve signals begin with a change in membrane potential
b. The Action Potential (a nerve impulse)
i. Voltage-gated channels
- only open at certain membrane
potentials
- examples
- voltage-gated Na+ channel
Opens at a membrane
potential of -50mV
- voltage-gated K+ channel
Opens at +30mV
Chapter 28: Nervous Systems
AIM: How do neurons transmit signals?
I. Nervous Systems
McGraw Hill Animation
G. Nerve Signals and their transmission
2. Nerve signals begin with a change in membrane potential
b. The Action Potential
1. Neuron is at resting potential (-70mV)
Fig. 28.4
Chapter 28: Nervous Systems
AIM: How do neurons transmit signals?
I. Nervous Systems
G. Nerve Signals and their transmission
2. Nerve signals begin with a change in membrane potential
b. The Action Potential
1. Neuron is at resting potential (-70mV)
2. A stimulus is applied
- causes Na+ channels to open
- Voltage begins to rise (depolarization)
- IF voltage reaches “threshold”
potential (-50mV),
Fig. 28.4
Chapter 28: Nervous Systems
AIM: How do neurons transmit signals?
I. Nervous Systems
G. Nerve Signals and their transmission
2. Nerve signals begin with a change in membrane potential
b. The Action Potential
1. Neuron is at resting potential (-70mV)
2. A stimulus is applied
- causes Na+ channels of dendrites and cell body
to open
- Voltage begins to rise (depolarization)
- IF voltage reaches “threshold”
potential (-50mV), Voltage-gated
VG-Na+ channels at the beginning
of the axon called the axon
hillock will open.
3. Na+ rushes in and inside
becomes positive relative to outside
Fig. 28.4
Chapter 28: Nervous Systems
AIM: How do neurons transmit signals?
I. Nervous Systems
G. Nerve Signals and their transmission
2. Nerve signals begin with a change in membrane potential
b. The Action Potential
4. Repolarize: Positive potential
causes Na+ channels to close and K+
voltage-gated channels to open.
- K+ diffuses down electrochemical
gradient
Reminder: Electrochemical gradient = down both
a chemical gradient (high to low concentration)
and a charge gradient (from + to - in this case)
Fig. 28.4
Chapter 28: Nervous Systems
AIM: How do neurons transmit signals?
I. Nervous Systems
G. Nerve Signals and their transmission
2. Nerve signals begin with a change in membrane potential
b. The Action Potential
5. Undershoot (hyperpolarize): K+
voltage-gated channels are slow to
close and potential across
membranes goes below -70mV…it
is now harder for the neuron to fire
again, but not impossible (need to
get it to -50mV).
6. Na+/K+ pump restores
membrane potential to -70mV
Fig. 28.4
Chapter 28: Nervous Systems
AIM: How do neurons transmit signals?
I. Nervous Systems
G. Nerve Signals and their transmission
2. Nerve signals begin with a change in membrane potential
b. The Action Potential
Chapter 28: Nervous Systems
AIM: How do neurons transmit signals?
I. Nervous Systems
G. Nerve Signals and their transmission
3. Action potentials propagate themselves down the neuron
a. The action potential moves along
the axon toward synaptic knobs
b. How come they only move in one
direction?
- Na+ gates are inactive at +50mV while
K+ gates are open
c. Action potential are ALL of NONE
and always the same (there are no
strong or weak/long or short signals
down a neuron)
d. So how do we know if something
hurts a little or a lot?
- it is all about the frequency of signal being
sent (many per second = very painful)
Fig. 28.5
Chapter 28: Nervous Systems
AIM: How do neurons transmit signals?
I. Nervous Systems
H. How are signals passed b/w neurons?
1. synapse
Fig. 28.5
a. Junction b/w two neurons or b/w
neuron and an effector cell (muscle cell)
b. Two types
1. Electrical synapse
- action potential (sodium) itself passes
directly b/w neurons / muscle cells
through gap junction like structures.
- heart and digestive tract muscle
2. Chemical synapses
- found everywhere else (CNS, PNS,
skeletal muscle, etc…)
Gap junctions can serve as
electrical synapses
Chapter 28: Nervous Systems
AIM: How do neurons transmit signals?
I. Nervous Systems
Fig. 28.6
H. How are signals passed b/w neurons?
2. Chemical synapses
a. Synaptic cleft
- narrow gap (20nm) b/w synaptic
knob and receiving neuron
b. Electric signal to chemical signal
to electric signal
c. Action potential causes voltagesgated Ca++ channels to open on
knob
d. Ca++ causes vesicles with
neurotransmitter to fuse with
membrane
http://brainu.org/files/movies/synapse_pc.swf
http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter14/animation__chemical_synapse__quiz_1_.html
Chapter 28: Nervous Systems
AIM: How do neurons transmit signals?
I. Nervous Systems
H. How are signals passed b/w neurons?
2. Chemical synapses
e. Neurotransmitters (NT)
- the chemical signal
- stored in vesicles at synaptic knob
- NTs diffuse across cleft and binds to
receptors (typically sodium Ligand-gated ion
channels, which aim to excite the neuron or
chlorine gated ion channels with make the
inside more negative and therefore serve to
inhibit the neuron from firing)
- new action potential generated if
threshold potential (-50mV) is reached
Q. How is a one-way signal ensured at synaptic cleft?
Fig. 28.6
Chapter 28: Nervous Systems
AIM: How do neurons transmit signals?
I. Nervous Systems
H. How are signals passed b/w neurons?
2. Chemical synapses
e. Neurotransmitters (NT)
- Where will the NTs go after binding
the receptors on the effector cell?
- They must somehow be cleared from
the synaptic cleft otherwise the effector
will keep getting the signal (ex. Your
muscle just keeps contracting)
- NT’s are either broken down by
enzymes, taken up via endocytosis by
the sending neuron and reused, or
diffuse away
Fig. 28.6
Chapter 28: Nervous Systems
AIM: How do neurons transmit signals?
Fig. 28.7
I. Nervous Systems
I. Making complex information
processing possible
1. Many inputs on a single neuron
2. Each sending neuron can secrete
i. different quantity of NT
ii. Different kind of NT
- excitatory = open Na+ channels
- inhibitory = open Cl- or K+ channels
3. Rate of signaling is the sum
(called summation) of ALL the
EPSP and IPSP. If the IPSP are
stronger than the EPSP, no signal
sent and vice versa.
Green = excitatory post synaptic potential (EPSP)
Red = inhibitory post synaptic potential (IPSP)
http://brainu.org/files/movies/synapse_pc.swf
Chapter 28: Nervous Systems
AIM: How do neurons transmit signals?
I. Nervous Systems
J. Types of neurotransmitters
1. Most are small nitrogen-containing molecules
2. Types
i. Acetylcholine (Ach)
- signaling in brain
- *****motor neuron to muscle (effector) signaling
- makes skeletal muscles contract
Chapter 28: Nervous Systems
AIM: How do neurons transmit signals?
I. Nervous Systems
J. Types of neurotransmitters
1. Most are small nitrogen-containing molecules
2. Types
ii. Biogenic amines (neurotransmitters derived from amino acids)
a. Examples
- epinephrine
- norepinephrine
- serotonin
- dopamine
b. Important in CNS
dopamine
serotonin
- serotonin and dopamine - effect sleep, mood, attention, learning
- schizophrenia associated with excess dopamine
- depression associated with reduced levels or norepinephrine and
serotonin
- Parkinson’s associated with lack of dopamine
Chapter 28: Nervous Systems
AIM: How do neurons transmit signals?
I. Nervous Systems
J. Types of neurotransmitters
1. Most are small nitrogen-containing molecules
2. Types
iii. Amino acids
a. Examples
- aspartate
- glutamate
Aspartate
GABA
- glycine
- GABA (gamma aminobutyric acid) – major inhibitory NT of the CNS
b. Important in CNS
- 100X more GABA in brain than all other neurotransmitters combined
Chapter 28: Nervous Systems
AIM: How do neurons transmit signals?
I. Nervous Systems
J. Types of neurotransmitters
1. Most are small nitrogen-containing molecules
2. Types
iv. peptides
a. Examples (both involved in pain perception)
- endorphins
- substance P
v. Dissolved gas
a. Nitric oxide (NO)
- memory storage and learning
- relaxes smooth muscle
Substance P
Chapter 28: Nervous Systems
AIM: How do neurons transmit signals?
I. Nervous Systems
K. Many drugs act at chemical synapses
1. Caffeine
- counters inhibitory neurotransmitters
2. Nicotine
- binds and activates acetylcholine receptors in nervous system
3. Alcohol (ethanol)
- believed to increase inhibitory effect of GABA in brain
4. Prozac
- blocks REMOVAL of serotonin from synapse
5. Valium, Xanax, amphetamines, cocaine, LSD, mescaline, opiates, etc…
Chapter 30: How animals Move
NEW AIM: What types of motor systems have evolved?
LOCOMOTION
Chapter 30: How animals Move
NEW AIM: What types of motor systems have evolved?
IIB. Chemotaxis vs. Phototaxis
A. Chemotaxis – process by which a cell directs their movement
depending on a chemical in the environment – taxis = to move (hence
the word taxi).
Ex. 1. Movement of sperm towards the egg (egg secretes chemicals that sperm are attracted to);
2.Movement of macrophages to a site of bacterial infection (broken cells release a chemical attractant)
3. Movement of bacteria to a high concentration of glucose
These are all examples of positive chemotaxis
(move towards the chemical)
There can also be negative chemotaxis
(move away from the chemical).
Chapter 30: How animals Move
NEW AIM: What types of motor systems have evolved?
IIB. Chemotaxis vs. Phototaxis
b. Phototaxis – process by which an entire organism directs their
movement depending the stimulus of light (this is NOT a plant moving
towards light, which is called phototropism).
Ex. 2. Moths or fruit flies attracted to light
Movement
Ex. 1. Algal cell moves toward light
(positive phototaxis)
Chapter 30: How animals Move
NEW AIM: What types of motor systems have evolved?
VI. Muscle contraction and movement
A. The skeleton and muscles interact in movement
B. Muscle system is an EFFECTOR of the nervous system
C. MUSCLES CAN ONLY CONTRACT (SHORTEN)
Origin of bicep
D. Insertion of a muscle
i. Portion attached to bone that moves
Insertion of bicep
E. The ORIGIN is the attachment
to the non-moving bone
Origin of tricep
Insertion of tricep
Fig. 30.7
Chapter 30: How animals Move
NEW AIM: What types of motor systems have evolved?
VI. Muscle contraction and movement
E. Extensor
i. Muscle that extends or straightens the bones at a joint
Ex. Tricep is an extensor - it contracts and straightens arm at elbow
F. Flexor
i. Muscle that bends a joint to an acute angle
Ex. Bicep is a flexor - it contracts and bends arm at elbow
Flexor
Bicep and Tricep are
antagonistic muscles
ALL animals have pairs of
antagonistic muscles
Extensor
Fig. 30.7
Chapter 30: How animals Move
NEW AIM: What types of motor systems have evolved?
VI. Muscle contraction and movement
G. Tendons (dense connective tissue)
i. Connect muscles to bones
Ex. Achilles tendon
Fig. 30.7
Chapter 30: How animals Move
NEW AIM: What types of motor systems have evolved?
VI. Muscle contraction and movement
H. Ligaments
i. Connect bones to bones
Chapter 30: How animals Move
NEW AIM: What types of motor systems have evolved?
VI. Muscle contraction and movement
I. Three types of muscles
i. smooth
ii. cardiac
iii. skeletal
- movement caused by
CONTRACTION in ALL 3
types
- Contraction caused by
sliding of actin and myosin
filaments past each other
inside cells…
Chapter 30: How animals Move
NEW AIM: What types of motor systems have evolved?
VI. Muscle contraction and movement
I. Three types of muscles
i. Smooth muscle
a. involuntary muscles (autonomic NS) in arteries and veins, gastrointestinal
tract, bladder, uterus
b. nonstriated
- simply means that actin and myosin do not
have clear organized arrays
c. smooth muscle cells connected by gap
junctions in tissues (allow action potential to
pass from one cell to next) - electrical synapse
d. Single nucleus per cell
Chapter 30: How animals Move
NEW AIM: What types of motor systems have evolved?
VI. Muscle contraction and movement
I. Three types of muscles
ii. Cardiac muscle
a. Single nucleus per cell
b. striated
- actin and myosin have clear organized arrays
c. connected by gap junctions in tissues (allow
action potential to pass from one cell to next) electrical synapse
d. Involuntary (autonomic NS)
Chapter 30: How animals Move
NEW AIM: What types of motor systems have evolved?
VI. Muscle contraction and movement
I. Three types of muscles
iii. Skeletal muscle
a. Voluntary (intentional physical movement; somatic NS)
b. Muscle cell = single, large, multinucleated fiber
c. striated
- actin and myosin have clear organized arrays
d. Stimulated by nerves at neuromuscular
synapses
e. Action potential along surface of muscle
cell stimulates calcium release into
cytoplasm, which in turn causes contraction
Chapter 30: How animals Move
AIM: How do muscle fibers contract?
VIII. Neuromuscular junction
Fig. 30.10
Chapter 30: How animals Move
AIM: How do muscle fibers contract?
IX. How does a motor neuron make a muscle fiber contract?
1. Action potential (AP) reaches synaptic knob
2. Acetylcholine released into synaptic cleft
3. Sodium moves through muscle fiber
(just like a neuron)
4. AP travels along T-tubules
(membranous tubules that fold in
through cells) deep into the fiber
Neuromuscular junction video on website
Fig. 30.10
Chapter 30: How animals Move
AIM: How do muscle fibers contract?
IX. How does a motor neuron make a muscle fiber contract?
1. Action potential (AP) reaches synaptic knob
2. Acetylcholine released into synaptic cleft
3. Sodium moves through muscle fiber
(just like a neuron)
4. AP travels along T-tubules
(membranous tubules that fold in
through cells) deep into the fiber
5. AP causes Ca++ to be
released from sarcoplasmic
reticulum (SR = ER) of muscle
cell (myocyte) into cytoplasm
Muscle action potential video on website
Fig. 30.10
Chapter 30: How animals Move
AIM: How do muscle fibers contract?
IX. How does a motor neuron make a muscle fiber contract?
Acetylcholine will be broken down by
the membrane-bound enzyme
(protease) acetylcholinesterase in
the neuromuscular junction in order to
terminate the signal to the muscle.
Fig. 30.10
Chapter 30: How animals Move
NEW AIM: How do muscle fibers contract?
VII. Muscle contraction
A. Skeletal muscle
i. Muscle composed of bundles of fibers (cells)
ii. Muscle fibers (cells) contain numerous
myofibril (contractile protein structures)
- striation = alternating light and dark band of
myofibrils
iii. Sarcomere - repeating unit of the myofibril
(region b/w two Z lines) – you see sarco- you think muscle
- thin filament: two strands of actin polymers
and one strand of regulatory protein
- thick filament: staggered array of multiple
myosins
- dark band vs. light band
Fig. 30.8
Chapter 30: How animals Move
NEW AIM: How do muscle fibers contract?
Sarcomere contraction video on website
VII. Muscle contraction
B. Sliding-filament model
Fig. 30.9
Chapter 30: How animals Move
AIM: How do muscle fibers contract?
VII. Muscle contraction
B. Sliding-filament model
1. ATP binds to myosin head (causes detachment
from actin)
2. ATP hydrolyzes to ADP and Pi
- energy used ratchet back the head
- head is now in an unstable (high energy) state
3. Head binds to actin
4. ADP and Pi are released resulting in the power
stroke
5. ATP binds, head releases, repeat again, but grab
the next actin closer to Z-line
Sliding filament video on website
Fig. 30.9
Chapter 30: How animals Move
AIM: How do muscle fibers contract?
VII. Muscle contraction
B. Sliding-filament model
1. ATP binds to myosin head (causes
detachment from actin)
2. ATP hydrolyzes to ADP and Pi
- energy used ratchet back the head
- head is now in an unstable (high energy) state
3. Head binds to actin
4. ADP and Pi are released resulting in the power
stroke
5. ATP binds, head releases, repeat again, but grab
the next actin closer to Z-line
Aside: Rigor Mortis
– when an animal dies, it becomes stiff (hence why we call dead people stiffs).
This is because ATP is needed to release the myosin head from the actin
filaments. No ATP, no release, muscle can’t relax.
Fig. 30.8
Chapter 30: How animals Move
AIM: How do muscle fibers contract?
IX. How does a motor neuron make a muscle fiber contract?
6. Myosin binding sites on actin usually blocked by regulatory strand
(troponin and tropomyosin)
7. Ca++ binds to part of regulatory strand (troponin) of thin filament,
which causes tropomyosin to move off myosin binding site so myosin can
bind.
Muscle action potential video on website
Fig. 30.10
Chapter 30: How animals Move
AIM: How do muscle fibers contract?
IX. How does a motor neuron make a muscle fiber contract?
http://www.tvermilye.com/pmwiki/pmwiki.php?n=Animation.Video12
Fig. 30.10
Chapter 30: How animals Move
AIM: How do muscle fibers contract?
X. Vocabulary for a skeletal muscle cell
A. Sarcolemma: plasma membrane
B. Sarcoplasmic reticulum (SR): endoplasmic reticulum
C. Sarcomere: single unit of the myofibril
D. Sarcoplasm: cytoplasm
Chapter 28: Nervous Systems
NEW AIM: What kinds of nervous systems have evolved?
ANIMAL BEHAVIOR
Chapter 28: Nervous Systems
NEW AIM: What kinds of nervous systems have evolved?
II. Behavior in animals (Chapter 37)
A. Innate behavior
- Behavior that appears to be performed the same way by ALL individuals of a
species
1. Simple relfexes
i. Automatic response to simple stimuli
ii. Controlled at spinal level in vertebrates
Fig. 28.1
Chapter 28: Nervous Systems
NEW AIM: What kinds of nervous systems have evolved?
II. Behavior in animals (Chapter 37)
A. Innate behavior
- Behavior that appears to be performed the same way by ALL individuals of a
species (a complex reflex)
2. Fixed action patterns (FAPs)
i. Can only be performed as a
whole from start to finish
ii. Once an animal initiates an FAP,
it usually carries sequence to
completion regardless of external
stimuli
Graylag goose
retrieving an
egg
Fig. 37.3A
Chapter 28: Nervous Systems
NEW AIM: What kinds of nervous systems have evolved?
II. Behavior in animals (Chapter 37)
A. Innate behavior
- Behavior that appears to be performed the same way by ALL individuals of a
species
FAPs in a European Cuckoo
2. Fixed action patterns (FAPs)
i. Can only be performed as a
whole from start to finish
ii. Once an animal initiates an FAP,
it usually carries sequence to
completion regardless of external
stimuli
iii. Built into the neurons (a
complicated reflex)
iv. Activated by a specific stimulus
Fig. 37.3B
Chapter 28: Nervous Systems
NEW AIM: What kinds of nervous systems have evolved?
II. Behavior in animals (Chapter 37)
A. Innate behavior
- Behavior that appears to be performed the same way by ALL individuals of a
species
2. Fixed action patterns (FAPs)
i. Can only be performed as a
whole from start to finish
ii. Once an animal initiates an FAP,
it usually carries sequence to
completion regardless of external
stimuli
Web building
iii. Built into the neurons (a
complicated reflex)
iv. Activated by a specific stimulus
yawning
Mating dance
Chapter 28: Nervous Systems
NEW AIM: What kinds of nervous systems have evolved?
II. Behavior in animals (Chapter 37)
B. Learned behavior
- a change in the way an animal behaves based on experience (i.e. learning)
Table 37.4
Chapter 28: Nervous Systems
NEW AIM: What kinds of nervous systems have evolved?
II. Behavior in animals (Chapter 37)
B. Learned behavior
1. Habituation (desensitization)
- loss of response to a stimulus after repeated exposure
Ex. Poke a snail once and it retracts into shell, keep poking and it will no
longer retract (nervous system learns to ignore the stimulus)
Do crows remain afraid of a scarecrow forever?
Do you feel the closes touching your skin all over your body right now?
Chapter 28: Nervous Systems
NEW AIM: What kinds of nervous systems have evolved?
II. Behavior in animals (Chapter 37)
B. Learned behavior
1b. Sensitization (opposite of habituation)
- A repeated stimulus creates a stronger reflex response.
Ex. Rub your arm continuously…
At first your arm will warm up, but eventually it will become painful
Chapter 28: Nervous Systems
NEW AIM: What kinds of nervous systems have evolved?
II. Behavior in animals (Chapter 37)
B. Learned behavior
2. Imprinting
- imprinting is learning that interacts
closely with innate behavior
- limited to a specific time period
and is generally IRREVERSIBLE
-important in forming offspring/parent
relationship in many species:
Chapter 28: Nervous Systems
NEW AIM: What kinds of nervous systems have evolved?
II. Behavior in animals (Chapter 37)
B. Learned behavior
2. Imprinting
- imprinting is learning that interacts
closely with innate behavior
- limited to a specific time period
and is generally IRREVERSIBLE
-important in forming offspring/parent
relationship in many species:
Fig. 37.5
Chapter 28: Nervous Systems
NEW AIM: What kinds of nervous systems have evolved?
II. Behavior in animals (Chapter 37)
B. Learned behavior
2. Imprinting
i. Konrad Lorenz experiment
- Lorenz was “imprinted” into the
minds of the goslings as “momma”
- found critical imprinting period for
graylag goose to be 2 days after
hatching
- The critical period for imprinting is
innate, but the actual imprinting is
learned
http://www.youtube.com/watch?v=LGBqQyZid04
Fig. 37.5
Chapter 28: Nervous Systems
NEW AIM: What kinds of nervous systems have evolved?
II. Behavior in animals (Chapter 37)
B. Learned behavior
3. Associative learning - learn that a specific stimulus or response is linked to
a reward of punishment
i. Classical conditioning - association of an involuntary or automatic
response with an environmental stimulus
Pavlov’s experiment (1927)
i. Food (unconditioned stimulus; UCS) causes
salivation (unconditioned response; UCR)
ii. Ring bell (neutral stimulus), no salivation
occurs
iii. Ring bell when giving food, salivation occurs
iv. Eventually, ring bell alone (conditioned
stimulus; CS) causes salivation (conditioned
response; CR)
- associates bell with food
Chapter 28: Nervous Systems
NEW AIM: What kinds of nervous systems have evolved?
II. Behavior in animals (Chapter 37)
B. Learned behavior
3. Associative learning - learn that a specific stimulus or response is linked to
a reward of punishment
ii. Operant or Instrumental conditioning - conditioning a voluntary
response (a behavior) to a stimuli (reinforcement/punishment)
- B.F. Skinner (1930’s)
- Skinner Box:
a. Press lever when light is green
- get food (positive reinforcement; reward)
b. Press lever when light is red
- get shocked (positive punishment)
- associates response to reward/punishment
Chapter 28: Nervous Systems
NEW AIM: What kinds of nervous systems have evolved?
II. Behavior in animals (Chapter 37)
B. Learned behavior
3. Associative learning - learn that a specific stimulus or response is linked to
a reward of punishment
ii. Operant or Instrumental conditioning - conditioning a voluntary
response (a behavior) to a stimuli using a reward (reinforcement)
Reinforcement vs. Punishment
Reinforcement – anything that makes the behavior more frequent
Punishment – anything that makes the behavior less frequent
Positive vs. Negative
(has nothing to do with something that is positive or negative in nature like a lolly pop vs. a slap in the face)
Positive – when something is given to the organism
Negative – when something is taken away from the organism
Now put the terms together…
Chapter 28: Nervous Systems
NEW AIM: What kinds of nervous systems have evolved?
II. Behavior in animals (Chapter 37)
B. Learned behavior
3. Associative learning - learn that a specific stimulus or response is linked to
a reward of punishment
ii. Operant or Instrumental conditioning - conditioning a voluntary
response (a behavior) to a stimuli using a reward (reinforcement)
1. Positive reinforcement
- You will make the behavior more frequent by giving something to the
organism (a reward)
Ex. You jump in the air, I give you five bucks…guess what you do again…
2. Negative reinforcement
- You take something away to reinforce the behavior
Ex. A rat is placed in a cage and given a mild shock until is presses a lever. When it releases the lever,
a another shock is delivered causing is to press the lever again.
Ex. The beeping noise in the car goes off when you put your seat belt on.
Chapter 28: Nervous Systems
NEW AIM: What kinds of nervous systems have evolved?
II. Behavior in animals (Chapter 37)
B. Learned behavior
3. Associative learning - learn that a specific stimulus or response is linked to
a reward of punishment
ii. Operant or Instrumental conditioning - conditioning a voluntary
response (a behavior) to a stimuli using a reward (reinforcement)
3. Positive punishment
- You will make the behavior less frequent by giving something to the organism
Ex. The rat presses the lever and gets shocked. The shock will cause the rat to press the lever less often.
Ex. Every time you turn in your homework late, I give you detention. This will reduce the frequency of turning in
ones homework late.
4. Negative punishment
- You will make the behavior less frequent if you take something away.
Ex. Your cell phone is taken away if your grades are poor. Getting poor grades is the behavior we want
to extinguish and we take away the cell phone to accomplish this.
http://www.wagntrain.com/OC/Part2.htm
Chapter 28: Nervous Systems
NEW AIM: What kinds of nervous systems have evolved?
II. Behavior in animals (Chapter 37)
B. Learned behavior
3. Associative learning - learn that a specific stimulus or response is linked to
a reward of punishment
Differences Between Classical & Operant Conditioning:
- Classical conditioning is passive on the part of the learner.
- Operant conditioning relies on the learner to actively participate in the learning process.
- In operant conditioning reinforcers act as incentives for learning.
- Classical conditioning, on the other hand, does not provide incentives.
Chapter 28: Nervous Systems
NEW AIM: What kinds of nervous systems have evolved?
II. Behavior in animals (Chapter 37)
B. Learned behavior
3. Associative learning - learn that a specific stimulus or response is linked to
a reward of punishment
iii. Extinction
- organisms eventually unlearn the conditioned response in the
absence of reinforcement – ring the bell often without giving food
Chapter 28: Nervous Systems
NEW AIM: What kinds of nervous systems have evolved?
II. Behavior in animals (Chapter 37)
B. Learned behavior
3. Associative learning - learn that a specific stimulus or response is linked to
a reward of punishment
iv. Trial and error learning (operant conditioning in nature)
- learn to associate behavioral act with a positive or
negative effect
Fig. 37.6B
- Behavioral act linked to a negative effect
Chapter 28: Nervous Systems
NEW AIM: What kinds of nervous systems have evolved?
II. Behavior in animals (Chapter 37)
c. Intraspecific interactions (interactions within a species
1. Behavioral displays ( tend to be innate - FAPs)
i. Mating dance/song
ii. Agnostic displays (dog wagging its tail)
iii. Antognisitc displays (hair standing up when threatened)
iv. “waggle dance” of the scout honeybee
http://www.youtube.com/wa
tch?v=-7ijI-g4jHg
Chapter 28: Nervous Systems
NEW AIM: What kinds of nervous systems have evolved?
II. Behavior in animals (Chapter 37)
c. Intraspecific interactions
2. Pecking order or dominance hierarchy
i. Ranking of individuals based on social interaction
ii. Social heirarchy of a group
iii. Minimizes violent intraspecific aggressions
- alpha wolf = dominant wolf in pack
- omega wolf = lowest ranking member
Chapter 28: Nervous Systems
NEW AIM: What kinds of nervous systems have evolved?
II. Behavior in animals (Chapter 37)
c. Intraspecific interactions
3. Territoriality
- area defended by most land-dwelling species from intrusion by
other members of same species (conspecifics = same species)
- used for mating, nesting, and/or feeding (i.e. resources)
- shown by a minority of species
Sunbathers
Gannets at a nesting ground
Cheetah spray-urinating
Chapter 28: Nervous Systems
NEW AIM: What kinds of nervous systems have evolved?
II. Behavior in animals (Chapter 37)
c. Intraspecific interactions
4. Behavioral cycles
i. Circadian rhythms
- daily cycles of behavior
- based on natural light/dark cycles
Ex. - Sleep and wakefulness
- Feeding patterns
- brainwave activity
- hormone production
- cell regeneration
Chapter 28: Nervous Systems
NEW AIM: What kinds of nervous systems have evolved?
II. Behavior in animals (Chapter 37)
c. Intraspecific interactions
5. Altruism
i. Behavior that reduces the fitness of the individual, while
increasing the fitness of the recipient
- ex. Female workers in honeybee hives are sterile, but they spend
their life helping the one fertile queen reproduce.
How is this a selective advantage for the alleles of the nonreproducing individuals? Kin selection
ii. Kin selection
- the genes coding for altruistic behavior will increase if those
benefiting from the act also carry those genes (related individuals
help each other since they have similar genes)
Chapter 28: Nervous Systems
NEW AIM: What kinds of nervous systems have evolved?
II. Behavior in animals (Chapter 37)
c. Intraspecific interactions
5. Altruism
iii. Recipricol altruism and non-kin cooperation
- help another individual if the act can be repaid at a later date
Ex. Certain dolphins will help unrelated members raise their
young in return for help with their young later, but nothing
compares to human non-kin cooperation…this is our
“trick”…our biggest advantage and may all stem from out
ability to kill from a distance (to throw). Distance killing allows
us to coerce each other into doing “the right thing”, without
threat to ourselves (there is little threat to a gunman pointing a gun at a
person even if the gunman is much smaller and weaker). The coercion
allows us to control out desire to be selfish and “force” people
to help non-related individuals. We have since been able to
evolve minds that behave in this fashion, which is the only
reason I am able to speak to you now.