nervous system Flashcards
describe the resting state of an axon (where is Na and K, is it negative or positive)
- in the resting state of an axon is negative because most of what is in the axon is negative (DNA/RNA, proteins and ions)
- Na(sodium) is on the outside of the axon
- K (potassium is on the inside of the axon
describe how action potential occurs, why is it called and all or none reaction
- resting state, sodium in on the outside, potassium inside and voltage is 70mv
- sodium channels open and sodium rushes in
- potassium gates are open and potassium rushes out (called repolorization
- everything is on the wrong side and sodium/ potassium pump returns axons to resting state
this is an all or none reaction because all action potentials are the same size, there is no in-between. a neuron either responds or doesn’t
what is saltatory conduction why is it faster
saltatory conduction is the propagation of action potentials along myelinated axons. from one node to the next node increasing the conduction velocity of action potentials
saltatory conduction is faster because rather than traveling down each node, salta in latin means leaps and in saltatory conduction the signal leaps down the axon so its faster
how does a nerve signal cross the synapse what is a neurotransmitter
- nerve signals cross the synapse using neurotransmitters
- a neurotransmitter is a chemical substance that is released at the end of a nerve fiber by the arrival of a nerve impulse and diffuses across the synapse
what are the major parts of the brain and what do they do
brain stem- not conscious, heart pumping , digestive system, sleep , bottom most part
diencephalon- plays sensory info( not smell), controls hormones, maintains homeostasis
cerebellum- motor- coordination, motor/muscle memory, don’t have to think about it
cerebrum- 2 main sides , 4 main sections, frontal lobe, side lobe, parietal lobe, and oxypital lobe. (What we think of as our brain)
what does the somatic nervous system control the automatic?
somatic- voluntary and controls skeletal muscle
automatic- involuntary controls parasympathetic and sympathetic nervous system
what does the sympathetic and parasympathetic nervous system do
parasympathetic- “resting and digesting”- usually under control of this
sympathetic-“ fight or flight”- in scary enviroments
describe your sense of taste
you use ur taste buds
sweet- craving for sweet things sour- acid H+ salty-Na+ bitter- toxic umami- savory - detects the amino acid glutamate
describe how u smell
you smell by inhaling hair which contains odor molecules, which binds to the olfactory epithelium( the size of a post stamp) and controls many neurons then the receptors transfer messages to the brain
Describe the structure of the eye and how you see
the light first passes through a protective sheet called the corniea. the amount of light that enters is controlled by radial muscles called the iris. the light travels through the pupil( hole) and through the lens which is adjustable and bends light to focus on the retina. the retina is covered in rods and cones which change shape when hit by light, triggering an electrical message that travels through the optic nerve to the brain.
what portion of you ear is involved in balance
the portion of you ear involved in balance is your semi-circular canals located in your inner ear, m they are required for balance and sends signals to your brain about head position
trace the path sound waves take in your ear before they reach the cochlea
sound waves enter the ear through the pinna and thought the autotory (ear) canal and reach the tympanum (eardrum) and causes it to vibrate and the n the sound waves passes through the middle ear drum (which amplifies the sound) and then they go in. the cochlea and stimulates little hair cells
how does your sense of tough work
happens in the skin
-dermis has light and deep pressure receptors _ when membrane bends and sodium rushes in (more bend + more pressure)
- epidermis has pain receptors (nosoreceptors)
how do action potentials travel form on e neuron to the next
action potentials travel from one neuron to another by traveling through the axon until it reaches an axon terminal, then the calcium gates open and calcium rushes in then the diffusion of synapse happens
