Chpt 38 - Part 1 - Nervous System Flashcards
Define Neural circuit
a pathway of information transfer between individual, interconnected neurons
Give an example of a neural circuit
Convergence - eyes
Define nervous systems
neural circuits together with supporting cells
Who has the simplest nervous system?
Hydras and other cnidarians
How does the nervous system work in small, radial bodies like hydras and other cnidarians?
- have individual interconnected neurons that form a diffuse nerve net
What do nerve nets do ?
control contraction and expansion of gastrovascular cavity
Elongated bilaterally symmetrical animals have more complex nervous systems that include
- cephalization
- nerves
Define cephalization
-clustering of interneurons at the anterior (front) end of the body that carries out integration
…what creates a central nervous system (CNS)
- often includes a brain and a clustering of sensory neurons
How do they CNS work in planarians and other non segmented worms?
- small brain
- longitudinal nerve cords
-simplest out of the other two complex CNS
What are nerves?
- neuron axons bundled together into fibrous channels that organization info flow around the body …. Peripheral nervous system
- nerves carry info toward and away from the CNS
What do invertebrates have?
A ventral nerve cord
What is a ventral nerve cord?
- along the underside
- coordinates neural signaling between brain and body in both directions
- major structure of the insect nervous system
- contains ganglia
- functional equivalent of the dorsal spinal cord in vertebrates
Define ganglia
clusters of neurons that serve as relay points in informational transfer
- segmented
What do vertebrates have?
A dorsal nerve (spinal) cord
What is a dorsal nerve (spinal) cord?
- Runs along the backside
- coordinates neural signaling between brain and body in both directions
- contain sensory ganglia
- functional equivalent to the ventral nerve cord in insects
Brain + Spinal cord =
Central nervous sytem
Nerves + sensory ganglia =
Peripheral nervous system
What are the 4 examples of animal nervous systems discussed in class?
- hydra
- planetaria, worms
- insects
- salamander - vertebrate
What is the vertebrate nervous system composed of?
- Peripheral nervous system
- Central nervous system
Sensory information reaches the CNS along the __
afferent PNS neurons
Following info processing by the CNS, instructions travel to effectors along __
efferent PNS neurons
What are the two major divisions in the Peripheral efferent?
- motor system
- autonomic system
What does the Peripheral nervous system control?
smooth muscles
cardiac muscles
glands (endocrine system)
What does the motor system do?
Regulation of skeleton muscles ONLY
Voluntary + Reflexes
What does the autonomic system do?
-regulation of cardiac and smooth muscles
- involuntary
- splits into three sub divisions
What are the 3 sub divisions of the autonomic system?
- Sympathetic
- parasympathetic
- enteric
Sympathetic + Parasympathetic have
complimentary antagonistic (opposite) effects on organs they both have connection to
What do Sympathetic neurons do?
- promote a state of hyperarousal (fight or flight)
- heart beats faster, digestion slows, pupils dilate
What do Parasympathetic neurons do?
-promote a state of calming and self maintenance
- rest and digest
- heart beat slows, digestion up regulated (increases) pupils constrict.
What is the Enteric system?
- neurons that carry signals to smooth muscles to regulate organs of the digestive system ONLY
- own distinct network of neurons
What does the Enteric nervous system do?
- can act completely independently of input from any other component of the vertebrate NS
- tho it interacts with the autonomic NS to regulate digestion when appropriate
- Second brain (probably evolved first)!
What is the vertebrate brain composed of?
- Forebrain
- Mid brain
- Hindbrain
What does the hind brain do?
- reflex responses
- homeostatic functions
What does the mid brain do?
Sensor routing and integrating center
signals/coordination
What does the fore brain do?
integration center
learning, memory, emotions
complex processing tasks
What part of the brain is the hypothalmus?
mid brain
What are the 3 patterns to recognize when it comes to vertebrate brains?
- Birds & mammals have 6-10x larger brains than similarly sized reptiles
- Bony fishes and birds have large midbrains since they are swimming and flying
- Midbrain is smaller in mammals but the forebrain is larger
3a. midbrain is larger in birds
What is another name for the forebrain?
Cerebrum
What is the most superficial outer layer called?
Cerebral cortex
What is the cerebral cortex made up of?
Gray matter - clusters of neuronal cell bodies
What does the cerebral cortex control?
- voluntary movements and cognitive functions like
Sensory areas
Association areas
Motor areas
What are sensory areas?
receive and process sensory info from afferent neurons
- visual
What is the association area?
areas that integrate info and make decisions using interneurons
prefrontal cortex
What is the last to develop in kids brains?
the association area - prelobal front
What is the motor area?
transmit instructions to other parts of the body via efferent neurons
motor cortex
What are the 4 lobes in the cerebral cortex?
- Frontal
- parietal
- temporal
- occipital
What is laterlization?
since each lobe has specialized functions that are very different depending on the left or right side
Define cognitive ability
correlated with the degree of convolutedness (complexity)
- highest in primates and cetaceans
dolphins and whales greatest primates
If any animal has more lumps, ridges, and bumps (folds) what can we infer?
that they are more social and more smatter
have complexity to them
