BIOL 102 Final

nervous system functions

• receive input

• process information

• initiate response

sensory neurons

• collect information from an animal’s environment

• dendrites modified to respond to external stimulation, such as temperature, touch, taste, smell, light, or sound

motor neurons

• initiate an animal’s response to stimuli

• stimulate action by conveying signals to muscles or glands

interneurons

• interpret signals coming in from sensory neurons and relay them to motor neurons

• located only in the brain and the spinal cord

neurons

individual cells that specialize in carrying electrical signals

dendrites

sense and respond to stimulation from outside the cell and send that information toward the cell body

cell body

contains the nucleus and other cellular machinery

axon

long tube like projection that extends from the cell body and transmits signals to other cells

glial cells

support cells that protect, insulate, and nourish the neurons

myelin sheaths

• fatty coating insulating the axons

• prevents action potential from weakening as it travels

oligodendrocyte

bead-like structure that is strung along an axon

microglia

processes harmful bacteria and acts as the brain’s immune cells

astrocytes

• release gliotransmitters by exocytosis to send signals to neighboring neuron

• connect to blood vessels in brain and regulate local blood flow to neurons

synapse

junction between a neuron and another cell

excitatory

increases membrane potential and increases chance for threshold to be reached

inhibitory

decreases membrane potential and decreases for threshold to be reached

acetylcholine

neurotransmitter released by motor neurons at the point where they synapse with muscle cells

glutamate

• excitatory NT

• starts/continues action potential

• brain synapse

GABA

• inhibitory NT

• stops action potentials

increases, decreases

alcohol ——- GABA activity and ———- glutamate activity

cardiac muscles

• uninucleate

• striated

skeletal muscle

• straited

• voluntary

• multinucleate

smooth muscle

• involuntary

• uninucleate

• not striated

muscle, bundle of muscle fibers, muscle fibers, nuclei, myofibril, sarcomere, actin filaments, myosin filaments

order of muscle size

sarcomeres

• composed of large numbers of long filaments

• made from actin and myosin

sliding filament theory

sarcomere shortens because actin is pulled inward

motor unit

motor neuron + muscle fibers innervated by axon terminals of motor neuron

endocrine disruptors

chemicals manufactured by humans that can mimic, block, or interfere with hormones

endocrine cells

cells that secrete hormones

target cells

cells that receive signals

endocrine glands

large collections of hormone secreting cells

pheromones

transported to the outside of the body to cause a behavioral or physiological change in another individual

hypothalamus

• receives input from neurons throughout the brain and the rest of the body

• releases hormones that regulate nearly every aspect of an organism’s physiology

anterior pituitary

produces numerous hormones that direct endocrine glands elsewhere to release hormones

• thyroid, follicle, prolactin

posterior pituitary

releases 2 important hormones produced in hypothalamus

• oxytocin

• antidiuretic hormone

antidiuretic hormone

• maintains normal water concentration in the blood by regulating the amt of urine produced

pineal gland

• releases melatonin

• regulates sleep cycles

thyroid gland

• releases thyroxine

• influences the rate and efficiency of cellular metabolism

• regulated calcium levels in the blood

parathyroid glands

regulate calcium levels in the blood

adrenal glands

• release adrenaline and cortisol

• regulate organism’s response to stress

pancreas

• releases insulin and glucagon

• maintains blood glucose levels within a narrow range

gonads

• release the sex steroids, including testosterone, estrogen, and progesterone

• responsible for numerous physical, behavioral, and emotional features

thyroxine

• require iodine

• control rate of metabolism

• regulated by hypothalamus and anterior pituitary