Human nervous system Flashcards
Function of nervous system 3
Detect changes inside body or local environment
Process and store info (CNS)
Initiate responses
2 parts of nervous system?
Central nervous system
Peripheral nervous system
Components of CNS
Brain and spinal cord (and neurones)
Components of peripheral nervous system (PNS)
Comprised motor and sensory neurons etc
Effectors?
Muscles: contract
Glands: hormones
Meninges?
Tough protective membrane surrounding CNS
Function of sensory neurone
Carries nerve impulses from receptor cells to the coordinator
Somatic nervous system?
Nerves that originate in the brain or spinal cord, including sensory and motor neurones
Axon
Long cytoplasmic extensions which transmit impulses away from the cell body
Secondarily name for CNS
coordinator
Where are receptor cells found
In sense organs
Function of relay neurone
Receive impulses from sensory neurones (or other intermediate neurons) and send impulses to motor neurones (or other intermediate neurons)
Secondary names for relay neurones
Connector/ intermediate neurons
Location of relay neurones
In CNS
Function of motor neurones
Carry impulses from coordinator to effectors
Dendrites?
Thin extensions which carry impulses towards the cell body
Axon terminals
Long thread like extensions ending axon, can have synaptic knob
Schwann cells
Cells which surround neurones and insulate them
Myelin sheath
Made of schwann cells which grow, wrapping around the axon in several layers. Electrical insulator that speeds up transmission along the axon
What contributes to the insulating properties of the myelin sheath
Bc the schwann cells grow and wrap in multiple layers, there are several layers of cell membrane, made of phospholipids: electrical insulators
Nodes or Ranvier
Areas along the axon where the myelin sheath is missing
Cell body
Part of the neurone containing the typical cell organelles
Synaptic knob
Bulbous ending on axon terminals containing neurotransmitters
Do unmyelinated cells have Nodes of Ranvier?
No
Are relay neurones myelinated?
No
Relay neurones in comparison to motor and se sensory
Shorter axon
More branched axon terminals
Unmyelinated
autonomic nervous system
Controls involuntary action e.g contraction of smooth muscle in digestive track
