Nervous System Flashcards
Division of nervous system
central and peripher
Central Nervous System (CNS)
- Consists of Brain and spinal cord.
- Combines information from the entire body and coordinates activity across the whole organism
- most protected system of the body (three meninges and cerebrospinal fluid)
- contains nuclei (collection of cell bodies)
Peripheral Nervous System (PNS)
- Division of the nervous system containing all nerves that lie outside of the CNS
- connects CNS to organs, limbs and skin
- allows the brain and spinal cord to receive and send information to other areas of the body
- contains ganglia
Division of PNS
- Somatic nervous system (SNS)–> transmits sensory and motor signals to and from the central nervous system
- Automatic nervous system (ANS)–> controls the function of our organs and glands, and can be divided into the sympathetic and parasympathetic divisions
Divison of Automatic Nervous System (ANS)
(belonging to PNS)
- Sympathetic nerves –> project from CNS into lumbar and thoracic regions of the spinal cord
- Parasympathic nerves –> project from brain and sacral region of the spinal cord
Cells of Nervous system
Nurons and Glial cells
Anatomy of Neurons
Reception, Conduction and Transmission of electrochemical signals. Components are
- Dendrites
- Soma
- Axon
- Axon terminal
- Nucleus
Dendrites
Input zone : receice electrical and chemical messages through neurotransmitters
Messages are inhibitory or excitatory
-Inh.- no transmission to axon
-Exc.- transmission
Soma
Cell Body. Contains nucleus (Contains DNA and prduces Ribosomes)
Support structures are Endoplasmatic reticulum, Golgi apparatus and Mitochondria
- responsible for production of neurotransmitters and proteins
Axon Hillock
- Controls firing of the neuron
- Neurons integration zone (gathers and integrates imformation from synapses on dendrites and soma, converts into electrical impulses, sends it down axon)
Axon
Conduction zone. Carries information from body to terminal buttons.
Some axons covered in myelin sheath. Interruption through nodec of Ranvier
Axon terminal –> output zone
Terminal buttons
Small knobs at end of axon. Release of Neurotransmitters into synapses
Synapse
Communication sites where neurons pass nerve impulses among themselves. Separated by thin gap- synaptic cleft
Three categories of neurons
multipolar, unipolar and bipolar neurons
Bipolar neurons
Two processes. Found in PNS. Main function : transmitting sensory information to CNS (found in olfactory, visual, hearing -sensory functions)
Unipolar neurons
One process. Found in ganglia and spinal cord.
Multipolar neurons
Most common of neuron types. Many sets of dendrites and one main axon. Found in CNS- Motor function
Multipolar interneurons
Short axon/ no axon at all. Receiving information, processing and passing on information
Functions of Neurons
Sensory Neurons –> detect changes in external/internal environment, send info to CNS (mostly unipolar neurons)
Motor Neurons–> receive info from other neurons and convey commands to muscle organs and glands
Interneurons–> Short or no Axon in CNS. Passing on information.
Clusters of cell bodies
CNS = Nuclei, PNS= Ganglia
Bundles of nerve fibers (axons)
CNS= Tracts PNS= Nerves
Myelin providing glia
CNS= Oligodendrocytes, PNS= Schwann cells
