Respnding to Change Flashcards
(25 cards)
Describe how body temperature is reduced when you’re too hot
You sweat in order to let off heat
Your blood dilates to allow blood to flow near to the surface to release heat (vasodilation)
Erector muscles relax
What is homeostasis
Homeostasis is maintaining a stable internal environment
Describe how body temperature is increased when you’re too cold
Erector muscles contract to make hairs stand up which will trap a layer of air to stay warm
Very little sweat
Blood vessels will constrict (vasoconstriction) so that no blood is flowing near the surface
What are hormones
Hormones are chemical messengers
how do hormones travel around the body
In the blood
What name is given to the chemicals found at synapses
Neurotransmitters
List the four main difference between nerves and hormones
Nerves give a very fast message. Hormones give a slow message
Nerves act for a very short time. Hormones act for a long time
Nerves act on a specific area. Hormones are more general
Nerves are an electrical message, hormones are a chemical message
List the five sense organs and the receptors that each one contains
Eyes (light receptors) Ears (sound receptors) Nose (smell receptors) Tongue (taste receptors) Skin (touch pressure)
What does CNS stand for
Central nervous system
What does the CNS consist of
Brain and spinal cord
What does the CNS do
The CNS creates a response, decides what to do about the stimulus
It sends information to an effector (muscle or gland) along a motor neurone
What is the purpose of a reflex
Automatic response to certain stimuli
Reduce the chance of being injured
Describe the pathway of a reflex arc
A stimulus is detected by receptors
Impulses are sent along sensory neurones to the CNS
The CNS pass on the message to a relay neurone
Relay neurones relay the impulses to a motor neurone
They travel along the motor neurone to the effector
The muscle contracts
What happens when blood glucose is too high
When glucose levels are too high the pancreas will release insulin into the blood
Then some glucose is removed for the blood by the liver which turns it into glycogen
Describe what happens when blood glucose is too low
When it’s too low the pancreas will secrete glucagon into the blood
The glucagon goes to the liver and makes the liver turn the glycogen into glucose
The glucose is added into the liver
Glucagon stops being secreted
Describe how type 1 diabetes is controlled
Insulin injections into subcutaneous fat
What does it mean if someone is resistant to insulin
It means that they still produce insulin but it has no affect on their body
The body cells don’t respond to the hormone
How do you work out BMI
BMI = weight/(height)squared
What is the name given to a plants growth response to light
Phototropism
What is auxin
Auxin is a plant hormone that controls shoot and root growth
Makes cells elongate
Shoots are positively phototropic, what does this mean?
It means that they grow towards the sun
Roots are positively geotropic, explain the role of auxin in this response
Gravity produces an unequal distribution of auxin, the extra auxin inhibits growth so that the cells on top elongate faster and the roots bend downwards
List three things that gibberellin stimulate in plants
Seed germination
Stem growth
Flowering
Explain how plant hormones are used as selective weed killers
Have been developed so that it only affects the broad leaved plants (weeds) they disrupt the normal growth patterns
