Neural Signaling and Regulation (2)

Nerve cells (neurons)

receive signals at their dendrites and pass these along the axon for rapid communication

Afferent (sensory)

nerves carry signals to the brain or central nervous syste

Efferent (motor)

nerves carry signals out from the central nervous system

Resting membrane potential

Nerve has a negative charge inside and a positive charge outside

Action potential

an electrical signal that moves along the axon. Positive charge. All or nothing response.

Depolarization

when a stimulus opens the (Na+) sodium channels causing ______, enters positive charge flipping the membrane potential. Triggering K+ flow out of the neuron (repolarization)

Synapses (GAPS)

where action potentials are transmitted between nerve cells

Neurotransmitters

released by one nerve triggering the opening of ion channels on the next nerve.

Clostridium botulinum (Flaccid paralysis)

causes botulism by releasing a neurotoxin that blocks the release of acetycholine, a neurotransmitter in the muscles

Clostridium tetani (Spastic Paralysis)

causes tetanus by releasing a neurotoxin that blocks the release of inhibitory neutotransmitter

Signal Speed

greater axon diameters and myelin sheaths consisting of glial cells increases ________

Saltatory conduction

the process where action potential jumps between gaps between myelin called node of Ranvier

Mycobacterium leprae

Hansen's Disease (leprosy) caused by first infecting Schwann cells in the peripheral nervous system

Four functions of Sensory Pathways

Reception

Transduction

Transmission

Perception

Sensory receptors

interact directly with stimuli, both inside and outside of the body

Sensory Transduction

the conversion of stimulus energy into a change in the membrane potential of a sensory receptor (receptor potential). Magnitude varies with the strength of the stimulus

Sensory pathways

after transduction, some sensory cells generate the transmission of action potentials to the CNS. The frequency of action potentials is what encodes information about the strength of the sensory stimulation.

Sensory Perception

the representations of stimuli constructed in the brain. brain distinguishes stimuli from different receptors based on the area in the brain where the action potential arrive

Autonomic nervous system

governs involuntary body functions