cornea lens= more spherical lens with shorter focal lenght

thinner lens with longer focal lenght ( requiere less refraction)

suspensory ligaments- distant= flat - near= round/thick

HOMEOSTASIS- maintenance of a contant internal environment despite changes in surroundings.

control centre- the hypothalamus in brain decides on appropriate response. receptors- in the skin and brain detect changes in the body. effectors- E.G sweat glands body hair and thyroid glands change to increase/decrease body temp.

THERMOREGULATION- if the body is to cold/hot body temp. is adjusted to what it should be (negative feedback mechanisnm)- it involves receptor linked to the Hypothalamus- monitors core body temp. in brain- impulses sent to skin- skin reacts to change in body temp.

too cold (vasconstriction) receprtors too cold- impullses sent to control centre (brain)- control centre- best response- impulses sent to arterioles- arterioles near skin get smaller: shivering, muscles generate heat through respiration : sweat glands stop sweating : hairs up trapping warm air near body- less body heat lost

( VICE VERSA FOR TOO HOT- VASOLIDATION)

blood sugar levels 

food digested sugar,= glucose produced

sugar levels in blood too high- hyperglycemia / too low- hypoglycemia

hormone: insuline controls levels of sugar

HYPERGLYCEMIA

increase in glucose= glucose down metabollic pathways= toxic metabolities which cause: kidney damage, cardio, neuro, retina feet and legs damage

HYPOGLYCEMIA-

can cause confusion,abnormal behaviour or both

visual disturbances, loss of conscoiusness, seizures.

TROPISMS- a response to stimuli can be negative/positive

plants are very sensitive and their growth is affected by their enivronments. they respond to 3 types of stimuli: water,light and gravity.

PHOTOTROPISM-

plants grow towards the light

auxins made at the top of the shoot and move down the stem, speed up growth in a shoot.

GEOTROPISM-

shoots grow up (negative tropism)

roots down ( positive tropism)

auxins slow growth in roots

HYDROTROPISM-

roots grow towards water.