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AP Bio- Communication 5: Sensation, Integration, Response
Transcript of AP Bio- Communication 5: Sensation, Integration, Response
What is Sense?
How To Respond?
The Nervous System
How do nervous systems help animals coordinate and control their physiology?
How is the structure of the brain related to its functions?
Why do most responses in animals rely upon the skeletal/muscular system?
Make Sure You Can
Compare the major sensory apparati used by mammals and other animals.
Explain the relationships between the major divisions of the mammalian nervous system.
Explain the relationships between the major divisions of the human brain
Explain the causes of nervous system disruptions and how disruptions of the nervous system can lead to disruptions of homeostasis.
Explain how the skeletal-muscular system functions at the system and cellular levels.
Explain the sliding filament model of muscle contraction
Explain the causes of sensory and motor system disruptions and how those disruptions can affect homeostasis
Why Can We Run So Fast?
requires three things:
must be detected by a
2. The sensor must translate the stimulus into a nervous signal (an action potential).
3. The signal must be interpreted by the
central nervous system
All sensory apparatus have these three things in common!!!
The sensory receptor is either:
the first ("
") neuron in the signaling pathway
or it regulates the afferent neuron through
Touch sensations are mediated by receptors in the
There are many kinds of receptors in the skin:
hair movement receptors.
These are what people mean by
Since action potentials are binary, the
pattern of signals is what determines the sensation
Sight is mediated by
in specialized organs ("
Sound is mediated by receptors that vibrate in response to sound waves
Eyespots in Planaria
The planarian brain drives movement as long as light is shining on either
(movement away from light).
The ocellus only allows light from above to interact with neurons
The Vertebrate Eye
Light is focused by a
lining the back of the eyeball.
The retina translates light into nervous signals.
Information from each eye is routed to both
of the brain
interpret the presence/absence of light
respond to different wavelengths of light
Schematic of retina
Compound Arthropod Eye
Each eye contains many individual
Each facet has one fixed
UV illumination of some flowers suggests adaptation for arthropod pollinators
The Mammalian Ear
consists of a canal to direct soundwaves, and a series of bones and organs that interpret those waves as heard sound.
Much of hearing is due to
that line the
and vibrate at particular frequencies.
These vibrations stimulate afferent neurons.
Hair cells and ear anatomy are also involved in the detection of
of the body and subsequently balance
Normal hearing range occurs over a logarithmic scale of frequencies, with lower frequency vibrations being interpreted as lower pitch sounds.
Arthropod hearing is typically mediated by
on the the forelegs of the organism
in animals is mediated through taste and smell
Most animals sense the environment predominantly through chemoreception
Taste is mediated by
Taste buds interpret different molecules as different tastes
"Food" tastes "good"
Genetic variance is demonstrated to be responsible for some differences in taste preferences.
Smell is interpreted when molecules ("
") interact with receptors on the cell membranes of chemoreceptors that protrude from the
of the brain.
Human sense of smell is vastly less pronounced than that of typical mammals.
Smell is important for taste as well, as odorants are released into the nasal cavity when food is chewed.
There are many examples of senses that are present in other animals but are absent in humans
Many reptiles have infrared radiation receptors
Bats and cetaceans use
system in fish detects energy signatures (currents, sound, etc) in water
Many insects have chemoreceptors on their antennae which are particularly sensitive to mating pheromones
Evolutionary Progression of Nervous System complexity.
: No CPU
Central Nervous system
of sensory organs.
Human Nervous System
Actions Do Not Require CNS Processing (only relay)
Fundamentally, the Brain consists of
- perhaps 500 trillion synapses
EMG of Cerebral Cortex
Brainbow staining of neurons
One Glial Cell
Development of the human brain
Like an onion!
= cell bodies, nerve terminals, dendrites
The Brain Has Specific Sections
Seat of Endocrine Control
- Autonomic System
- Balance, coordination
- "Higher order" functions
Different cerebral regions participate in different functions
" of the brain
Human vs. Avian Brain
route from/to different regions of the body.
Different Regions of the Brain Are Active for different tasks
Dolphins sleeping one hemisphere at a time
fMRI showing word-related brain activity
involved in emotional response
involved in reward response
Lots of "Black Boxes" left:
Roughly: The more used a synaptic pathway is, the more firm that pathway becomes
Long Term Potentiation
: A lasting synaptic connection.
Roughly: Disruptions in normal neurotransmitter release and reuptake contributes to mental illness.
Some mental illnesses seem to have a genetic component.
Much better understanding & treatment than 50 years ago!
Roughly: It is still hard to predict the effect that brain damage will have on an individual.
lived for 12 years following this injury
Though his personality changed drastically
: Associated with destructive protein plaques in the brain.
Is it "brain damage"?
Evidence of neural stem cells in a mouse hippocampus.
Major animal Response:
- voluntary motion
- lines organs, involuntary
- heart, independent
Only skeletal is under conscious control!
Muscle cells do two things:
Skeletal muscles are arranged in "
Typical Muscle Structure:
is bundle of
Each fiber is a bunch of
Each cell has a collection of
Each myofirbril is packed with
) and myosin (
) filaments, arranged in "
Muscle fiber (nuclei in blue)
Muscle fiber (nuclei in purple)
ATP is hydrolyzed to move myosin between active (high energy) and inactive (low energy) conformations
Active: Myosin bonds to actin (forming a "
") and pulls it towards the middle of the sarcomere.
Inactive: Myosin remains attached to actin until ATP hydrolysis occurs again.
": Actin and myosin slide past each other.
Calcium ions must be present in the sarcomere, and bonded to
for myosin to bond to actin.
Calcium is stored in a region of the sarcomere called the "
The nervous system interfaces with muscle tissue at modified synapses called "
The release of
into the NMJ is responsible for calcium ion release into the sarcomere.
" terminate at NMJ's
A motor neuron and its NMJ's are called a "
Total muscle contraction ("
") is only initiated when enough motor units are activated ("
Stonefish venom induces involuntary tetanus.
Wear your Flip Flops!
The human skeleton is an
During early life, bones grow.
Bones are awesome!
Living Bone is constantly broken down and reformed by populations of bone stem cells.
Some bone tissue ("
") is also the site of blood cell production.
: Connections between bones.
All Vertebrates have
Advantage: Internal-grows with the organism
Disadvantage: Interntal- soft flesh on top
Annelids have a
No Bones (good for squishiness)
Structure is maintained by internal pressure.
Animals have three options
There are energy considerations
Arthropods and molluscs have
Advantage: Protects all soft tissue beneath.
Disadvantage: Doesn't grow with the organism, must be periodically shed ("
Microscopic image of human cerebral cortex showing the delineation between gray matter and white matter.
I'ma get my molt on