LIFESCI 15 Lecture Notes - Lecture 16: Peripheral Nervous System, Central Nervous System, Zygosity
Document Summary
#4: heterozygosity better equips org. to deal with a changing environment. Symmetric individuals have higher fitness, possibly due to heterozygosity. Your body has two systems for responding to stimuli and coordinating info within the body: hormones, neurons, each has strengths and weaknesses. Sensory receptors (eyes, ears, nose, fingertips) >>[sensory input]>> integration (brain and spinal cord) >>[motor output]>> effectors (muscles, glands) How neurons work: signal, initiated somewhere else in body in response to external stimuli. Travels from dendrite through cell body and down the : axon, electrical signal (na+, in, k+ out) travels down until, synapses with, 1) muscle: causing contraction, or 2) another neuron: causing firing/no firing. --> contrary to earlier beliefs: yes: london cab drivers. Bigger hippocampus and the longer they had been a cab driver, the larger their hippocampus ( use it or lose it! ) Take home message #1: neurons are specialized for receiving electrical and chemical info via dendrites and transmitting it via axons.
