Unit 5 Edexcel A2 Biology

Answers on back of card:

which part of the brain detects a tempriture rise?

name two responses which help to cool the body:

which types of heat loss are caused by sweating (eg, conduction)

What kind of feedback is produced when the body is cooled to the correct tempriture?

Blood tempriture rises

Detected by hypothalumus

impulses are sent to effectors to cool the body

(eg, sweating and flushed skin- caused by vasodiatation and increased sweat secreation takes place)

skin tempriture rises

so heat loss increaes due to radiation and convection

and blood tempriture falls

then heat loss measures stop (negative feedback)

Answers on back of card:

where are nerve impluses in reflex archs sent?

where does the moter neuron leave the spinal cord?

which part of the spinal cord does the sensory neuron's synaps take place and to which neurone?

pain receptors in skin detect stimulus

sensory conducts nerve impluse to CNS

entering the spinal cord through dorsal route

sensory neuron synapses with interneuron in gray matter of spinal cord

this then synapes with moter neron

moter neurton leaves spinal cord through ventral root

and carries impluse to effector

making a synaptic connection with mucel (effector)

mucel contracts and hand is withdrawn

Answers on the back:

When rhodopsin absorbs light what is the produce?

What creates an action potential in the eye?

what is the name of the inhibitory neurtotransmitter?

Which channels does opsin open?

light enters retina

reaches vesicles in outer segment of rod cell

Rhodopsin absorbs light and is broken down into retinal and opsin

opsin closes Na+ channels in outer segment of rod cell

and is pumped out from the inner segment making the membrain hyperpolarised

this stops the release of an inhibitory neurotransmitter (glutamate) form the synapse of the rod cell

cation channels of the bipolar cell open because there is no inhibitory neurotransmitter

an action potential is produced in bipolar cell

this travels to the optic nerve

What do the Ca+ pass through to get into the mucell?

what happens to tropomyosin when troponin is pushed out of the way?

what causes the myosin head to be pulled to the center of the sarcomere?

Ca+ flood into mucel fibers through sarcoplasmic reticulem

they bind to troponin and change its shape

when this happens, tropomyosin is pushed out of the way

exposing the binding sights on actin molecules

myosin head binds to actin filiments and pulles it to the centre of the sarcomere

the myosin head hydolisises ATP providing eneregey for the release of the myosin head

the head then recocks for another cycle

what is the name of the neurotransmitter between the parasympethetic and moter neurone?

which neurone stimulates the circular mucells to contract?

what is the receptor cell called that detects light?

increasin levals of light fall on rod cells in retina

impulses travel along sensory neurons of optic nerve to the brain

and reach the center for co-ordinating pupil reflex

the impuses travel along the parasympathetic neurone to the moter neurone

(the neruotransmitter is acetile-choline)

moter neurone stimulates circular mucells in irus

which contract to decrease the size of the pupil