chapter 25. which characteristic of life is an organism’s nervous system related to?
TRANSCRIPT
![Page 1: Chapter 25. Which characteristic of life is an organism’s nervous system related to?](https://reader036.vdocuments.mx/reader036/viewer/2022081501/56649f205503460f94c38a48/html5/thumbnails/1.jpg)
Unit 12: Nervous Control
Chapter 25
![Page 2: Chapter 25. Which characteristic of life is an organism’s nervous system related to?](https://reader036.vdocuments.mx/reader036/viewer/2022081501/56649f205503460f94c38a48/html5/thumbnails/2.jpg)
The Role of the Nervous System
Which characteristic of life is an organism’s nervous system related to?
![Page 3: Chapter 25. Which characteristic of life is an organism’s nervous system related to?](https://reader036.vdocuments.mx/reader036/viewer/2022081501/56649f205503460f94c38a48/html5/thumbnails/3.jpg)
Nervous Response
4 requirements before nervous response can occur:1. Detection of stimulus
by sensory receptors2. Transmission of
impulse along neurons3. Interpretation &
analysis of impulses in coordination center▪ brain or spinal cord
4. Response by effectors▪ muscles or glands
![Page 4: Chapter 25. Which characteristic of life is an organism’s nervous system related to?](https://reader036.vdocuments.mx/reader036/viewer/2022081501/56649f205503460f94c38a48/html5/thumbnails/4.jpg)
Nerve TissueNerve
many neurons bundled together
Neurons specialized cells that
transmit nerve impulses through body▪ different types▪ sensory neurons▪ interneurons▪motor neurons
![Page 5: Chapter 25. Which characteristic of life is an organism’s nervous system related to?](https://reader036.vdocuments.mx/reader036/viewer/2022081501/56649f205503460f94c38a48/html5/thumbnails/5.jpg)
Different Types of Neurons
Sensory neurons transmit impulses
from receptors to coordination center
Interneurons transfer impulses
from sensory to motor neurons▪ in brain & spinal cord
Motor neurons transmit outgoing
impulses to effectors
![Page 6: Chapter 25. Which characteristic of life is an organism’s nervous system related to?](https://reader036.vdocuments.mx/reader036/viewer/2022081501/56649f205503460f94c38a48/html5/thumbnails/6.jpg)
Neuron Structure dendrites
conduct impulses toward cell body
cell body resembles other
types of cells▪ contains nucleus
& cytoplasm axon
carries impulses away from cell body▪ often covered
with myelin sheath
end branch
![Page 7: Chapter 25. Which characteristic of life is an organism’s nervous system related to?](https://reader036.vdocuments.mx/reader036/viewer/2022081501/56649f205503460f94c38a48/html5/thumbnails/7.jpg)
Neuron Structure
cell body (soma) axon
terminal buttons (end branch)
cytoplasmnucleus
dendrites
myelin sheathnodes of Ranvier
![Page 8: Chapter 25. Which characteristic of life is an organism’s nervous system related to?](https://reader036.vdocuments.mx/reader036/viewer/2022081501/56649f205503460f94c38a48/html5/thumbnails/8.jpg)
Transmitting Impulses Along a Neuron
nerve impulse or “action potential” results from
changes in ion concentration inside/outside neuron plasma membrane
![Page 9: Chapter 25. Which characteristic of life is an organism’s nervous system related to?](https://reader036.vdocuments.mx/reader036/viewer/2022081501/56649f205503460f94c38a48/html5/thumbnails/9.jpg)
Transmitting Impulses from Neuron to Neuron
between each neuron is a synapse small fluid-filled
spaceneurotransmitters (chemicals) help impulse across synapse
![Page 10: Chapter 25. Which characteristic of life is an organism’s nervous system related to?](https://reader036.vdocuments.mx/reader036/viewer/2022081501/56649f205503460f94c38a48/html5/thumbnails/10.jpg)
Nervous Systems
In bilaterally symmetrical animals the nervous system is divided into 2 parts central nervous system (CNS)
peripheral nervous system (PNS)
![Page 11: Chapter 25. Which characteristic of life is an organism’s nervous system related to?](https://reader036.vdocuments.mx/reader036/viewer/2022081501/56649f205503460f94c38a48/html5/thumbnails/11.jpg)
Coordination between the PNS & the CNS
receptors in PNS gather info about animal’s environment impulses along the
PNS’s sensory neurons travel to CNS▪ in CNS (brain & spinal cord) impulses are interpreted & analyzed impulses leaving CNS by
motor neurons of PNS are carried to effectors which carryout response
![Page 12: Chapter 25. Which characteristic of life is an organism’s nervous system related to?](https://reader036.vdocuments.mx/reader036/viewer/2022081501/56649f205503460f94c38a48/html5/thumbnails/12.jpg)
![Page 13: Chapter 25. Which characteristic of life is an organism’s nervous system related to?](https://reader036.vdocuments.mx/reader036/viewer/2022081501/56649f205503460f94c38a48/html5/thumbnails/13.jpg)
3 Major Parts of the Brain
cerebrum speech, reasoning,
emotionscerebellum
controls balance, posture, muscle tone
medulla (oblongata) controls involuntary
actions of internal organs▪ heart rate, breathing rate,
peristalsis, etc.
![Page 14: Chapter 25. Which characteristic of life is an organism’s nervous system related to?](https://reader036.vdocuments.mx/reader036/viewer/2022081501/56649f205503460f94c38a48/html5/thumbnails/14.jpg)
What are reflexes? reflexes = involuntary/automatic responses
to stimuli Involve CNS, but require no conscious control or
decision making b/c determined by fixed pathways▪ some through brain (ex. blinking)▪ others through spinal cord (ex. touch hot iron & respond)
![Page 15: Chapter 25. Which characteristic of life is an organism’s nervous system related to?](https://reader036.vdocuments.mx/reader036/viewer/2022081501/56649f205503460f94c38a48/html5/thumbnails/15.jpg)
Reflexes: Initial Response & Reflex Arc
Reflex arc1. Receptors activated2. Sensory neuron
transmits impulse towards spinal cord
3. Impulse crosses synapse to interneuron in spinal cord
4. Impulse crosses synapse to motor neuron & leaves spinal cord
5. Impulse activates effectors which respond appropriately
Does NOT involve brain
Reflex Arc Animation
Reflex Arc Animation 2
![Page 16: Chapter 25. Which characteristic of life is an organism’s nervous system related to?](https://reader036.vdocuments.mx/reader036/viewer/2022081501/56649f205503460f94c38a48/html5/thumbnails/16.jpg)
2. Sensory neuron
transmits impulse towards
spinal cord
3. Impulse crosses synapse into
interneuron where interpreted &
analyzed
4. motor neuron transmits impulse
away from spinal cord
1. Sensory receptor activated (receives stimulus)
5. Impulse received by
effector (which responds
appropriately)
![Page 17: Chapter 25. Which characteristic of life is an organism’s nervous system related to?](https://reader036.vdocuments.mx/reader036/viewer/2022081501/56649f205503460f94c38a48/html5/thumbnails/17.jpg)
Interneuron = association nerve
ReflexArc
![Page 18: Chapter 25. Which characteristic of life is an organism’s nervous system related to?](https://reader036.vdocuments.mx/reader036/viewer/2022081501/56649f205503460f94c38a48/html5/thumbnails/18.jpg)
Reflexes: Secondary Response
Since reflex actions (arcs) don’t involve the brain, how does your brain become aware? Some spinal cord interneurons that
receive sensory impulses connect w/ other neuron pathways leading to the brain▪ Brain becomes aware of what has happened▪ Secondary response occurs
You yell, “Ouch!”
![Page 19: Chapter 25. Which characteristic of life is an organism’s nervous system related to?](https://reader036.vdocuments.mx/reader036/viewer/2022081501/56649f205503460f94c38a48/html5/thumbnails/19.jpg)
Comparison of Nervous Systems
![Page 20: Chapter 25. Which characteristic of life is an organism’s nervous system related to?](https://reader036.vdocuments.mx/reader036/viewer/2022081501/56649f205503460f94c38a48/html5/thumbnails/20.jpg)
Euglena Light-sensitive structure
under the “eye-spot”▪ Allows Euglena to swim in
direction of lightParamecium
Can respond to obstacles in path▪ Turns 30 & moves forward again…▪ Continues to do this until passes object
▪ Seems to be mainly under chemical control
Nervous Systems in Unicellular Organisms
![Page 21: Chapter 25. Which characteristic of life is an organism’s nervous system related to?](https://reader036.vdocuments.mx/reader036/viewer/2022081501/56649f205503460f94c38a48/html5/thumbnails/21.jpg)
Nervous Systems in Invertebrates
Radially symmetrical organisms have no center for nervous control Many short neurons form
nerve net▪ No definite nerve pathways
Ex. Hydra Bilaterally symmetric
animals have a primitive control center(s) (ganglia) & specific nerve pathways Ex. Planaria
![Page 22: Chapter 25. Which characteristic of life is an organism’s nervous system related to?](https://reader036.vdocuments.mx/reader036/viewer/2022081501/56649f205503460f94c38a48/html5/thumbnails/22.jpg)
Other bilaterally symmetric animals also have brains Ex. earthworm▪ cerebral ganglia
(slightly larger ganglia) Ex. grasshopper▪ Brain divided into
specialized areas▪ protocerebrum▪ deutocerebrum
Nervous Systems in Invertebrates
![Page 23: Chapter 25. Which characteristic of life is an organism’s nervous system related to?](https://reader036.vdocuments.mx/reader036/viewer/2022081501/56649f205503460f94c38a48/html5/thumbnails/23.jpg)
Nervous System in Fish
Lateral line system can sense the
slightest movements (vibrations) in water
Electrical sense Ampullae of Lorenzini▪ sense changes in
electrical fields
![Page 24: Chapter 25. Which characteristic of life is an organism’s nervous system related to?](https://reader036.vdocuments.mx/reader036/viewer/2022081501/56649f205503460f94c38a48/html5/thumbnails/24.jpg)
Questions to Ponder& Extras
How do we see unity within diversity in relation to nervous control???
How does form follow function???
Kid’s Health website http://
kidshealth.org/PageManager.jsp?lic=1&article_set=59295&cat_id=20607