Chapter 11: Control: The Nervous and Endocrine Systems

-detects and interprets info from the surrounding environment

-controls body functions through the use of chemical messengers called hormones

• AKA neurons • highly specialized cells that carry impulses between body parts • consists of cell body, dendrites, axon terminal, nucleus, myelin sheath

-polarized (inside of neuron is negatively charged)

• around -70 mV - RMP is set up and maintained by 2 membrane proteins (Na+/K+ ATPase and the K+ leak channel)

-protein channel that uses one molecule of ATP to pump 3 Na+ out of the cell and 2 K+ into the cell

-potassium channels that are always open and will always allow K+ to leak out of the cell according to its gradient, allowing for a negative charge in the membrane

• once the threshold (-50mV) is reached with a small influx of sodium, voltage-gated sodium and potassium channels open • sodium enters the cell with concentration gradient, depolarizing the cell further (until 35 mV) before the sodium channels shut • voltage-gated potassium channels open, allowing potassium to exit with the concentration gradient, repolarizing the cell and reaching -90mV before closing • membrane proteins return to the RMP

-make up the myelin sheath (speeds rate at which action potential can travel down the axon)

-spaces between the Schwann cells that can fire an action potential

-the jumping of the axon potential from node to node that increases the traveling of the signal

• membrane is unable to fire a second action potential until resting potential is set • ensures that signal travels down one direction

-neuron-to-neuron or neuron-to-organ junction that releases neutrosmitter (chemical such as Acetylcholine that can lead to alzheimers disease) to pass the impulse

• small gap between neurons • neurotransmitters are released into synapse by exocytosis where they diffuse across the synaptic cleft and bind to the receptors on the dendrites • then usually causes the opening of sodium ion channels so sodium flows into the cells, allowing for the threshold to be reached

-some cause the cell to be stimulated (reach threshold), inhibited (away from threshold)

-sum of stimulatory and inhibitory input

-brain and spinal cord that process and integrate info, and then sends decisions to body through PNS

-part of the CNS that connect sensory and motor neurons

-sends info to the CNS from sensory organs

-neurons involved in sending info from the CNS to the organs of the body

-determines how often the threshold is reached, and therefore how strong the stimulus is

-primitive, reflex actions

-conscious mind (movement, speech, problem solving, senses)

-coordinates movement and balance