Nervous System, Neurons, And Neurotransmitters Flashcards
Nervous system
- Central nervous system
- peripheral nervous system
Central nervous system (CNS)
- brain and spinal cord
Peripheral nervous system (PNS)
- transmit signals between the CNS and rest of the body
- somatic and autonomic nervous systems
Somatic nervous system (SNS)
- transmits information from bodies sensory receptors to CNS and CNS to skeletal muscles
- responsible for actions that are voluntary
Autonomic nervous system (ANS)
- transmits information from smooth muscles and organs to CNS and vice versa
- responsible for activities that are involuntary, although some activities can be brought under voluntary control using biofeedback or other techniques
- sympathetic and parasympathetic nervous systems
Sympathetic nervous system
- prepares body for action
- during fight or flight causes people dilation sweating increased heart rate and respiration rates and inhibits digestion and sexual activity
Parasympathetic nervous system
- rest and relaxation
- causes body to return to pre-emergency state after fight or flight
Parasympathetic and sympathetic nervous system
- both active to some degree most of the time and work together cooperatively for some functions
Ex) sexual response parasympathetic nervous system necessary for erection and sympathetic nervous system responsible for ejaculation
Neurons
- responsible for communicating information to the nervous system
Glia
- provide neurons with structural support, insulation, and nutrients
- produces myelin
Nervous system
- two types of cells: neurons and glia
Structure of neuron
- very in size and shape
- all have one or more dendrites, Soma and an axon
Dendrites
- receive information from other cells
Soma
- contains nucleus, mitochondria, ribosomes, and other elements essential for the survival of the cell
Axon
Transmits info to other cells
- some are insulated with myelin with speeds up conduction of information
Conduction within neurons
- information conduction is an electrochemical process
- begins with neurons dendrites receiving sufficient stimulation from other neurons
- prior to stimulation neuron is in resting state (fluid inside is negatively charged)
- once it stimulated sufficiently channels in the cell membrane open allowing a positively charged sodium ion to enter cell which makes it become depolarized
- once simulation reaches minimum threshold complete depolarization occurs and triggers an electrical impulse (action potential)
- after action potential neuron returns to arresting state
Action potential
- all or nothing responses
- Have same intensity
- stimulus intensity is encoded by frequency of action potentials or number of neurons that generate action potentials
Transmission between neurons
- transmission of info equals synaptic transmission
- chemical
- begins when action potential reaches acts on terminal which causes the release of a neurotransmitter into synaptic cleft
Once neurotransmitter hasn’t affect on a post gymnastic neuron it is an activated by being absorbed by a priestsynaptic neuron or broken down by an enzyme
Axon terminal
End of an axon
Synaptic cleft
- space between the axon terminal of the priestsynaptic neuron and the dendrite of an adjacent postsynaptic neuron
Neurotransmitters
- have an excitatory or inhibitory effect