Lecture 8 & 9 Flashcards
Central Nervous System
brain & spinal cord (acts as the integrating center)
Efferent Nervous System
transmits impulses from the CNS out to the peripheral organs to cause an effect or action. ?
Afferent Nervous System
transmits impulses from peripheral organs to the CNS. ?
Efferent Neurons
a peripheral neuron that carries signals from the CNS to the target cells
Autonomic Neurons
efferent neurons that control smooth muscle, cardiac muscle, many glands, & some adipose tissue
Somatic Motor Neurons
efferent neurons that control skeletal muscles
Parasympathetic
division of the autonomic nervous system that is responsible for day-to-day activities
Sympathetic
division of the autonomic nervous system that is responsible for fight-or-flight response
Tissue Response
The response of living tissues to altered conditions or types of restorative materials, metals or cements. ?
Enteric Nervous System
neurons in the wall of the gastrointestinal tract that are capable of sensing & integrating information & carrying out a response without input from the CNS
Sensory Signal
Sensory signals are converted to electrical signals via depolarization of sensory neuron membranes upon stimulus of the receptor, which causes opening of gated ion channels that cause the membrane potential to reach its threshold. ?
Sensory Receptor
- monitor external conditions
- the sensory receptors of a neural reflex are not protein receptors that bind to signal molecules, like involved in signal transduction
- there are many sensory receptors in the body, each located in the best position to monitor the variable it detected
- those involved in natural reflexes are divided into central receptors & peripheral receptors
Sensory Neurons
a neuron that transmits sensory information to the CNS
Afferent vs Efferent
Afferent Arrives, Efferent Exits.
Afferent neurons are neurons whose axons travel towards (or bringing information to) a central point, while an efferent neuron is a cell that sends an axon (or carries information) away from a central point.
Interneuron
a neuron that is completely contained within the CNS
Pseudounipolar neurons
have a single process called the axon
- during development, the dendrite fused with the axon
Bipolar neurons
have two relatively equal fibers (a single axon & single dendrite) extending off the central cell body
Multipolar CNS interneurons
are highly branched (many dendrites & branched axons) but lack long extensions
a typical multipolar efferent neuron has 5 to 7 dendrites, each branching 4 to 6 times
- a single long axon may branch several times & end at enlarged axon terminals
Dendrite
thin, branched processes that receive & transfer incoming information to an integrating region within the neuron
Cell Body
part of the cell that contains the nucleus & many organelles
Axon Hillock
region of the axon where it joins the cell body
- often contains the trigger zone
Trigger Zone
the region of the axon where graded potentials are integrated & an action potential begins if the signal is above threshold
Node of Ranvier
unmyelinated regions on myelinated axons
Myelin Sheath
form insultating segments along axons
- formed by concentric layers of glial cell membranes compacted together
Synaptic Cleft
the space b/t the pre- & postsynaptic cells
Presynaptic Terminal
neurotransmitters are packaged into synaptic vesicles. When an action potential opens presynaptic voltage-gated Ca2+ channels, the neurotransmitters are released by Ca2+-triggered synaptic vesicle exocytosis into the synaptic cleft, where they activate postsynaptic receptors. ?
Postsynaptic Cell
the cell that receives the signal
Synaptic Vesicles
small secretory vesicles that release neurotransmitter into the synapse