GCSE WJEC Biology- response and regulation of the body

negative feedback → blood glucose level rises

pancreas releases insulin into blood → body cells absorb more glusoce + liver absorbs glucose and stores it as glycogen → blood gucose level declines

sense organ

groups of nerves

stimuli

specific changes in the environment

type 1 diabetes cause

body not producing insulin

type 2 diabetes cause

body cells not properly responding to insulin that’s produced

properties of reflex actions

• fast

• automatic

• protective

stimuli examples

light + sound + touch + temp + chemicals

hormones

chemical messengers carried by blood control many body functions

negative feedback → blood glucose level falls

pancreas release glucagon travels to liver → converts glycogen to glucose → blood glucose level rises and returns to optimum

sense organs send information along specialised cells called … to the … in the form of …

sense organs send information along specialised cells called NEURONES to the CENTRAL NERVOUS SYSTEM in the form of ELECTRICAL IMPULSES

synapse

point where 2 neurones meet + transfer information

response

reaction to a stimulus

effector (muscles/ glands)

carries out the response

effector/ motor neurone

carries nerve impulses to the effector- muscle

relay neurone

transfers a nerve impulse to the effector neurone

sensory neurone

carries nerve impulses to central nervous system

receptor

recieves the stimulus

central nervous system

brain + spinal cord

sweat gland

produces sweat to cool body when too hot

hair erector muscle

raises hair/ fur when body too cold

nerve endings

sensitive to different stimuli

pore

to let sweat get to surface of the skin

homeostasis

keeping internal environment constant no matter the external environment

sweat production in hot conditions

sweat pours onto skin surface evaporating taking excess heat from skin → cooler blood circulates and cools body (opposite in cold)

shivering in cold conditions

muscle contraction requires energy from respiration → releases heat to warm body (opposite in heat)

vasodilation in hot conditions

blood capillaries close to surface open up allowing more blood near surface → heat lost by radiation (opposite in cold- vasoconstriction)

erector muscle in cold conditions

contracts pulling hair upwards → traps a layer of air- insulates the skin (opposite in heat)

epidermis

layer of dead cells that protects the body

sebaceous gland

produces oily substance making hair + skin waterproof + reduces germ growth

blood capillary

carry blood and heat to surface of skin

hair follicle

a tube in the skin where a hair grows

subcutaneous gland

contains cells full of fat + oil to keep the body warm

insulin

REDUCES blood glucose levels when too high

controlling type 1 diabetes

control carbs eaten + inject insulin regularly

controlling type 2 diabetes

control carbs eaten + take tablets to reduce glucose level in blood

glucose is needed for

respiration

glucagon

INCREASES blood lucose levels when too low

alcohol effects

slows your reaction times + damages kidneys + liver

why glucose levels fall in a diabetic person

done exercise/ not eaten enough

negative feedback

a change from optimal internal conditions resulting in the body responding and restoring optimal conditions

factors controlled to maintain optimal conditions

temp + glucose + ph