Neuron Flashcards
Describe the endocrine system
Specialised to secrete hormones into blood. Slow overall coordination
Describe the nervous system
Transmit electrical impulses between 2 or more cells. Fast and precise
What are the functions of neurons? (3)
Generation/transmission of impulses. Impulses reach specific targets. Modifies target cell activity & allows selective control of target structures
How does the cell membrane become more and less negative inside?
More negative = hyperpolarisation, negative enter and positive leave. Less negative = depolarisation, positive enter and negative leave
Define electrotonic transmission
Passive where ions move inside cell along electrical gradient
Describe process of voltage-gated membrane channels (5)
Na+ channels open/close in response to electrical changes at membrane. Depolarisation, Na+ channels open and Na+ enter cell. Depolarises more and -50mV threshold reached
What are the consequences of depolarisation?
Na+ channels close and K+ channels open. K+ leave and membrane is repolarised. Close when resting potential restored.
Define hyperpolarisation
Briefly, less K+ ions inside than outside
What are the properties of action potentials? (4)
Don’t decay, all or nothing, not produced continuously, fast
Describe glia cells
Provide protected environment. Developed from neural stem cells, 1/10th size of neuron, but 10x more
Definition and purpose of micro glia
Small, defensive function. Produce chemicals to repair damaged neurons. Digest dead neurons (phagocytosis)
Describe oligodendroglia
Large, flat branches wrapping selves around axon. Fatty substances insulating myelin sheath. Soma = body
What are astrocytes?
Star-shaped, physical + nutritional support. Transport nutrients from blood vessels to neurons, holds in place, neural signalling
