IB Bio Neurobiology

iris

regulated size of pupil

pupil

admits light

retina

contains receptors for vision

aqueous humour

transmits light rays & supports eyeball

vitreous humour

transmits light rays & supports eyeball

rods

allow black & white vision in response to dim light (less brightness, more effective)

cones

allow color vision in response to bright light

fovea

area of densely packed cone cells where vision is most acute

lens

focuses light rays

sclera

protects & supports eyeball

cornea

focusing begins here

choroid

absorbs stray light

conjunctiva

covers sclera & cornea & keeps eye moist

optic nerve

transmits impulses to brain

eye lid

protects eye

simulus

change in environment of organism that is detected & causes response

reflex

unconscious response

reflex are

series of nerve impulses sent to spinal cord & back to motor neuron

pain receptors respond to what?

respond to stimuli of pain

reflex arc path

sensory neuron → spinal cord → motor neuron

what are types of stimuli that can cause pain?

heat, pressure, or chemicals produced by damaged tissue

pain receptors

oftentimes long neurons that run directly into CNS (spinal cord)

pain reflex arc = __ synapse reflex arc

2

where are the two synapse reflex arcs for pain?

1. btwn sensory neuron & spinal cord neuron
2. btwn spinal cord neuron & motor neuron

how do scientists fully understand an organism’s behavior?

look at behavior in popul (b/c only popul can evolve, not indiv)

example of natural selection

European Black Caps

* normal: nest during summer in Germany, travel to Spain during winter
* now: fly & nest in Britain (shorter distance)

how did European black caps gain an evolutionary advantage?

fly shorter distance → better choices for nesting sites → increase reproductive success

mechanoreceptors

type of nerve cells that respond to pressure

chemoreceptors

type of nerve cells that respond to specific chemical (numerous types)

what do chemoreceptors provide?

provide sense of taste & smell

why does food taste different when sick?

b/c chemoreceptors in nose = blocked or inhibited

thermoreceptors

type of nerve cells that respond to change in temp

photoreceptors

type of nerve cells that respond to light energy

sense organs

collect stimuli & send them to brain

grouping of rods vs cones

* rods - grouped in three
* cones - single (by itself)

what does explosion sound like in space?

nothing b/c sound travels thru atoms & molecules but space = “empty”

ears

capture sound waves

path of capturing sound wave

1. tympanic membrane vibrates
2. malleus - hammer
3. incus - anvil
4. stapes - strikes oval window → vibrates (“stirrup”)
5. stimulates hair cells → release neurotransmitters

higher amplitude…

louder sound