Physiology of a Neuron( Brain cell)  Dendrites: Receives stimuli Axon: Sends nerve impulses Axon Terminals: Sends nerve impulses to other neurons Synapses: The gap in-between neurons as shown below a.k.a Synaptic cleft  Neurotransmitters First Calcium gates open and calcium starts heading towards axon terminal then Synaptic Vesicle releases neurotransmitters which bind to postsynaptic receptors. Types: 1) Acetylcholine: secreted at neuromuscular junctions allows muscle to stimulate 2) Epinephrine: Can treat severe asthma attacks and allergic reactions 3) Norepinephrine: Can treat low blood pressure and heart failure 4) Dopamine: Plays a major role in reward-motivated behavior. Can treat symptoms of shock by improving blood flow 5) Serotonin: Primarily found in the gastrointestinal tract, blood platelets. Can affect mood and social behavior, appetite and digestion, sleep, memory and sexual desire and function. 6) GABA( Gamma-aminobutyric acid) : Inhibits or reduces the activity of the neurons or nerve cells Potentials and Polarization  When a neuron is not being stimulated it is said to be polarized . Potassium ions are on the inside of the cell (negative) and Sodium ions on the outside of the cell ( Positive) *neuron is more negative in the inside
Resting potential: When the neuron is said to be polarized like explained above If there is more sodium rushing into the cell through the voltage-gated ion channels and potassium leaving the cell the neuron will become depolarized. *That is the inside of the cell is more positive . Action potential: When the stimulus is strong enough that is surpasses a certain threshold , allowing the cell to become depolarized. When this fails it is called an all-or-nothing event Repolarization: The movement of Potassium out of the cell. Hyper polarization : When more Potassium ions leave the cell than it is needed for the polarized potential. Graded potential: When the neuron is said not to be polarized  Types Of Neurons Sensory Nuerons: Receive initial stimulus Ex. The paws of a cat has sensory neurons on the hand that are stimulated by touch Motor Neurons: A nerve cell forming part of a pathway along which impulses pass from the brain or spinal cord to a muscle or gland. ex. might stimulate muscle after sensory neuron senses touch Interneurons: Receive impulses from sensory neurons or send impulses to motor neurons Central Nervous System And Peripheral Nervous System  Central Nervous System: Brain and spinal cord. controls:
injuries/ illnesses that can damage the CNS permanently are :
Peripheral Nervous System: Outside of the brain and spinal cord ex. Legs and arms Sensory neurons all over body remind CNS of the stimuli . PNS is divided into the Somatic NS and the Autonomic NS The Somatic Nervous System: Where all the awareness of the external environment comes from This consists of 12 cranial nerves and Spinal Nerves.  Autonomic Nervous system also has sub divisions and is dived into the sympathetic and parasympathetic NS. Autonomic NS Regulates the function of internal organs like the lungs and the heart.  |
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