Nervous System And Nerve Cells Flashcards
What is the function of the NS?
Interact with the world around us and respond to changes in the internal environment
Detects changes and receives info from our sense organs
What is the nervous system divided into?
Central NS and Peripheral NS
What is the central NS divided into?
The brain and spinal cord
What is the function of the CNS?
Receive info from the body and process it, sending out instructions
What is the function of the Peripheral NS?
Detects changes in the external/internal environment and sends info to CNS
What is the function of the neurones?
Carry messages as electrical or chemical impulses, allowing rapid communication
What is the function of dendrites?
Specialised to receive chemical signals from axon terminals of other neurones and conduct it toward the cell body
What is the function of the cell body (soma)?
The cell body containing a nucleus, cytoplasm and other organelles
What is the function of axons?
Long processes specialised for the conduction of action potentials away from neuronal cell body
Forms fine branches- ‘axon terminals’ at distal end
What is the function of the myelin sheath?
Fatty layer covering over the axon
Protects and insulates the axon
Speeds up transmission of impulses
What is the function of the nodes of ranvier?
Gaps formed between myelin sheath along the axons
Allow ‘skipping’ of impulse facilitating faster transmission
What is a sensory neurone?
Carries nerve impulses from sensory receptors to the CNS
What is a motor neurone?
Carries nerve impulses away from CNS to muscles/glands
What is an interneurone?
Connects sensory and motor neurones to form a reflex arc
What are nerves?
Collections of nerve cell axon
What do Schwann cells form?
Form specialised myelin sheath of axons in the PNS
What do Oligodendrocytes form?
Form myelin sheath of axons in the CNS
What is a reflex arc?
Protective mechanism
Quick and simple
Impulses do not need to travel to the brain to be processed to generate a response m
Connection made between sensory neurone and motor neurone in the spinal cord- via interneurone
What is an action potential?
Electrical impulse travelling down the axon body
When does an action potential occur?
Movement of charged particles across cell membrane
Sodium ions move into the nerve fibre and potassium ions move out
What is the threshold stimulus?
Minimum stimulus needed to achieve an action potential
