Organisation of the neuron system Flashcards
What are the basic functions of the nervous system?
sensory detection
information processing
Behaviour
learning and memory
what is sensory detection?
the process whereby neurons transduce environmental energy into neural signals
what are sensory receptors?
special neurons that are responsible for sensory detection
Examples of energy sensed?
light, sound, chemical, electrical field, temperature, mechanical forces.
information processing
transmission of information neural integration perception emotion planning and implementation of motor commands thought processes and learning
What is behavior?
the totality of the organism’s responses to its environment
three types of behaviour
convert, readily observable behaviour, language
Convert behaviour
mental processing
readily observable behaviour
movement and autonomic behaviour
AFFERENT
conduct impulses toward the CNS.
Efferent
conduct impulses away from the CNS
Somatic Nervous System
portion of the Nervous system concerned with the control of voluntary muscle.
Enteric Nervous system
Govern Gi function without external innervation.
innervates blood vessels and surrounding organs ( motility, secretion, growth of the Gi)
roles of the CNS
gathers information about the envirnment from the PNS.
Organises reflex and other behavioral responses
responsible for cogniition, learning and memory and plan executes voluntary movements.
what is the functional unit of a cell?
A neuron
what is a neuron?
a cell specialised for rapid communication
it receives information in the form of electrochemical signals from one neuron and relays it to the next in a sequence
What are the 4 distinct domains of a neuron?
Cell body, axon, presynaptic terminal and dendrites
Nerve cell body
contains the metabolic machinery of the cells
Nissl bodies
stacks of RER
Role of golgi appartus?
manufactures consituents, synethetic enzymes and neurotransmitters
Dendrites
relatively short, highly branched neural process that carries electrical activity to the cell body
role of dendrites
receive elctrochemical information from a previous neuron in a chain of relays . is membrane contain receptors that bind to neurotransmitters.
what are the main cytoplasmic organelles?
microtubules and neurofilaments
proximal dendrites contains of?
nissl bodies and parts of the golgi appartus
Axon
Conducts impulses away form the cell and may convey material back and forth between the cell body and the axon terminal.
what organelles does the axon hillock lack
RER, golgi appartus
Where does the axon arises from?
axon hillock
what are neurotransmitters?
endogenous chemicals that transmit nerve impulses between a neuron and another cell.
Example of a neurotransmitter
Dopamine, epinephrine, GABA, acetylcholine
what is a synapse?
the site at which one neuron chemically influences the next neuron in a chain or pathways of neurons.
which cells form myelin in PNS
schwann cells
function of satellite cells
support neuron cell bodies within the ganglion of the PNS
Functions of the myelin Sheath
Provides insulation to help prevent short circuiting between fibers.
Provides for faster conduction
Provides for the possibility of repair of peripheral nerve fibers.
Schwann cells help to maintain the micro-environments of the axons and their tunnel (the neurilemma tunnel) permits re-connection with an effector or receptor
disease that destroy the myelin?
Diseases which destroy the myelin sheath lead to inability to control muscles, perceive stimuli etc. e.g. multiple sclerosis, an autoimmune disorder in which your own lymphocytes attack the myelin proteins.
Neuron
- Axolemma – layer of myelin insulating the axon
- Neurolemma – thin membranous sheath around the nerve fiber
- Node of Ranvier – constriction in myelin sheath occurring at intervals along the axon
structure of a neuron
Nerve fibers, which are axons, organize into bundles known as fascicles
Each fascicle surrounded by the perineurium.
Between individual nerve fibers is an inner layer of endoneurium.
