Chapter 48/49 Flashcards
Neurons
Nerve cells that transfer information within the body
Neurons have two types of signals to communicate:
- Electrical signals (long-distance)
- Chemical signals (short-distance) AKA neurotransmitters
Most of a neuron’s organelles are in the _.
Cell body
Most neurons have _, highly branched extensions that receive signals from other neurons.
Dendrites
Axon
Typically a much longer extension that transmits signals to other cells
Synapse
A junction between the axon and another cell
Information is transmitted from a _ cell (a neuron) to a _ cell (a neuron, muscle, or gland cell).
Presynaptic; postsynaptic
Most neurons are nourished or insulated by cells called _ or _ cells.
Glia; glial
_ have numerous functions to nourish, support, and regulate neurons.
Glia (or glial cells)
Astrocytes
Form tight junctions in capillaries of the CNS, resulting in a blood-brain barrier which restricts the entry of most substances into the brain
Nervous systems process information in three steps:
1) Sensory input
2) Integration
3) Motor output
Sensors detect external stimuli and internal conditions and transmit information along _ neurons (step 1).
Sensory
Sensory information is sent to the brain or ganglia (in lower eukaryotes), where _ integrate the information (step 2).
Interneurons
Motor output leaves the brain or ganglia via _ neurons, which trigger muscle or gland activity (step 3).
Motor
Many animals have a complex nervous system that consists of:
- A central nervous system (CNS)
- A peripheral nervous system (PNS)
Central nervous system (CNS)
Where integration takes place; this includes the brain and a nerve cord (spinal cord)
Peripheral nervous system (PNS)
Carries information into and out of the CNS
The neurons of the PNS, when bundles together, form _.
Nerves
Ion pumps and ion channels establish the _ of a neuron.
Resting potential
Every cell has a voltage (difference in electrical charge) across its plasma membrane called a _.
Membrane potential
The _ is the membrane potential of a neuron not sending signals.
Resting potential