The Nervous System Flashcards
U4L7a (8 cards)
What are the two main divisions of the nervous system?
Central Nervous System (nerves, brain, spinal cord).
Peripheral nervous system
What are the two types of nerves the PNS carries?
Somatic Nerves: Skeletal muscles, bones and skin (sensory/motor).
Autonomic nerves: special motor nerves that control internal environment.
Sympathetic nervous system: fight/flight
Parasympathetic nervous system: nervous system (recovery)
The Sympathetic and parasympathetic nervous systems are branches of autonomic nerves. They work as opposites to eachother.
What are the two types of nerve cells?
Glial Cells: structural support. Provides nutrition to neurons (non-conductive)
Neurons: Nerve cells that conduct nerve impulses (functional unit). A nerve = bundle of many neurons.
What are the three typws of neurons?
Afferent (sensory) neurons: carry impulses from sensory receptors to CNS.
Efferent (motor) neurons: carry impulses from CNS to effectors (muscles, glands, organs).
Interneurons: link neurons within the body (found mostly in the CNS).
What is nerve cell anatomy?
Cell body: Nucleus/Cytoplasm
Dendrites: projections of cytoplasm that carry impulses towards cell body
Axon: extension of cytoplasm that carries nerve impulses away from cell body
Myelin Sheath: insulated covering over the axon. only some are myelinated.
nodes of Ranvier: gaps in the myelin sheath. meant to speed up the transmission.
What can the PNS do that the CNS cannot?
The PNS can regenerate white matter (myelinated) more than the CNS. Thats why spina cord injuries are often permanent.
What’s the reflex arc?
The reflex arc is the simplest nerve pathway. It usually occurs without brain coordination.
What are the five components a reflex arc contains?
Receptor
Sensory neuron (afferent)
interneuron
motor neuron (afferent)
effector
