生物英语词汇释义

1. a. Sensory Input

-Sensory receptors gather information about the internal and external environments and convert it to a form which can be used by the animal. This information is then conveyed to integration centers.

b. Integration

-The input is interpreted and associated with the bodies appropriate response. Integration is carried out in the Central Nervous System (CNS).

c. Motor Input

-Conduction of signals from the integration centers (CNS) to effecter cells.

2. -neuron: cells specialized for transmitting chemical and electrical signals from one location in body to another

a. large cell body; contains most of cytoplasm, nucleus, and other organelles

-cell bodies of most neurons located in CNS

-ome neurons have cell body located in ganglia outsidethe CNS

b.dendrites, one type of fiberlike extension (process) that convey impulses TO the cell body

-short, numerous, & extensively branched to increase surface area where cell most likely to be stimulated

c.axons, other type of extension (process), conduct signals AWAY from the cell body

-long, simple processes

-vertebrate axons in PNS wrapped in concentric layers of Schwann cells, which form insulating myelin sheath -in CNS, myelin sheath formed by oligodendrocytes

-axons extend from axon hillock (where signals are generated) to many branches which are tipped withsynaptic terminals that release neurotransmitters -synapse is gap between synaptic terminal and target cell—dendrites of another neuron or an effector cell -neurotransmitters are chemicals that cross the synapse to relay the impulse

3. Reflex Arc – A simple pathway involving neurons OUTSIDE the CNS. Signals do not go to the brain

4. -Nerve cells areas are also known as neurons. Neurons are the basic unit of the nervous system. They carry information or impulses as electrical signals from one place to another in the body. There are 3 types of neurons:a. Sensory Neurons- Sensory neurons carry electrical signals (impulses) from receptors or sense organs to the CNS. Sensory neurons are also called afferent neurons. The cell body of sensory neurons is outside the CNS in ganglia.

b. Motor Neurons- Motor neurons carry impulses from the CNS to effector organs Motor neurons are also called efferent neurons. The cell bodies of motor neurons are inside the CNS.

c. Interneurons- These are also called intermediate, relay, or associative neurons. They carry information between sensory and motor neurons. They are found in the CNS.

d. distinguish: In the central nervous system, a collection of neuron cell bodies is called a nucleus.

-In the peripheral nervous system, a collection of neuron cell bodies is called a ganglion (plural: ganglia).