Human Nervous System Flashcards
Central Nervous System
Includes the brain and spinal cord and acts as the centre of coordination
Peripheral Nervous System
It connects the CNS to the rest of the body by consisting of nerves that leave the spine
Somatic Nervous System
A part of the peripheral nervous system that involves voluntary control and nerves leading to skeletal muscles. It also has faster nerve transmission due to myelinated neurons (speed).
Autonomic Nervous System
A part of the peripheral nervous system that involves involuntary control and consists of the sympathetic and parasympathetic nervous system. It also has slower nerve transmission due to unmyelinated neurons.
Sympathetic
Nerves that transmit impulses during stress, so our fight or flight response. Due to this, heart rate and blood pressure increase along with other changes. Involves nerves that go from the spinal cord to the rest of the body.
Parasympathetic
Nerves that transmit impulses when the body is trying to get back to normal after a period of stress. It does this by slowing blood pressure, heart rate, etc. Involves nerves that go from the brain to the rest of the body.
Nerve
A bundle of neurons that transmits signals
Neurons
Basic unit of the nervous system that is specialized to conduct an electrical impulse
Dendrites
Receives stimulus and the branches of the dendrites help increase the surface area of the neuron
Axon
Carries impulse to the next neuron or effector
Soma
Also known as the cell body. It houses the nucleus
Myelin sheath
Insulating cover that speeds up the rate of nerve transmission. The presence of a myelin sheath is indicated by a white colour. The myelin sheath is made by glial cells called Schwann cells
Nodes of Ranvier
Spaces of an axon that are in between the myelinated sections. The nerve impulse for myelinated neurons jumps from node to node, which creates that faster transmission speed.
Grey matter
Unmyelinated neurons that don’t have a neurilema
White matter
Myelinated neurons that may have a neurilema
