Nervous System
Biology · तंत्रिका तंत्र · 16 facts
Nervous system: brain+spinal cord(CNS) + nerves(PNS)
Neuron: basic unit; cell body+dendrites(receive)+axon(transmit)
Brain: 3 parts - Cerebrum(thinking), Cerebellum(balance), Medulla(involuntary)
Cerebrum: largest part; intelligence, memory, reasoning, speech
Cerebellum: coordination, posture, balance
Medulla oblongata: controls breathing, heartbeat, BP, swallowing
Spinal cord: protected by vertebral column; reflex actions
Reflex action: automatic, quick response; spinal cord controls
Synapse: junction between two neurons; signal crosses chemically
5 sense organs: eyes(sight), ears(hearing), nose(smell), tongue(taste), skin(touch)
Autonomic NS: sympathetic(fight/flight) + parasympathetic(rest/digest)
Brain weight ~1.4kg; uses ~20% of body oxygen
CSF(Cerebrospinal fluid): protects brain+spinal cord from shocks
Neurotransmitters: acetylcholine, dopamine, serotonin carry signals
Nerves: sensory(to brain), motor(from brain), mixed(both)
Hypothalamus: controls body temperature, hunger, thirst