Co-ordination And Control Flashcards
What are the 3 main components of responding to a stimulus?
Receptors
Coordinator
Effector
What does the receptor do?
Receives / detects the stimulus
What does the coordinator do?
Determines the response
What does the effector do?
Carries out the response
What is the CNS
This is the brain and spinal cord. Together they are known as the central nervous system.
What does the aqueous and vitreous humour do for the eye.
Fluid that is needed to support the eye balk and allow light to pass through the eye to the retina
What is the function of the iris
Control how much light enters the eye
What is the function of the pupil
Space in the iris through which light passes
What is the function of the cornea
Transparent front part of the eye that causes some bending (refraction) of light
What is the function of the conjunctiva
Thin transparent protective outer covering that helps prevent the entry of microorganisms.
What is the function of the retina
Layers of light sensitive cells that can sense different coloured light (cone cells) as well as cells that don’t sense colour at all (rods)
What is the function of the lens
Refracts light to obtain a focused image
What is the function of the optic nerve
A bundle of neurones that carries impulses from the retina to the brain
How does the eye focus
By changing the shape of the lens
How does the eye focus on distant objects
The ciliary muscles relax, suspensory ligaments are pulled tight, this pulls the lens thin
How does the eye focus on near objects
Ciliary muscles contract, suspensory ligaments slackened, lens allowed to bulge
How are nurones adapted to carry electrical impulses
Long length- to carry impulses long distances
Insulating sheath- to allow rapid transmission of impulses
Branding ends- to receive or pass impulses to many other nerve cells
What are synapses
They are tiny gaps between nerve cells
What happens when an impulse reaches a synapse
1.The impulse reaches the synaptic bulb (end of neurone)
2.Vesicles containing the transmitter move towards the cell membrane at the synapse
3.Vesicles release their neurotransmitter into the gap between the 2 cells
4.Neurotransmitter diffuses across the gap
5.The neurotransmitter reaches the membrane of the next cell
6.When enough neurotransmitter reaches the next cell an impulse will occur
7.The impulse travels along the next cell
8.The used neurotransmitter is broken down by an enzyme
What are vesicles
Vesicles are “tiny packages” that carry the neurotransmitter
What are the the 2 basic types of response
Voluntary actions
Reflex actions
What is a voluntary action
It is a response where we have voluntary control over the action. The brain is the coordinator
What is a reflex action?
We are not conscious of these actions. Reflex actions tend to be much faster as they use a special pathway of nerves called the reflex arc.
What are hormones?
They are chemicals produced by special glands in the body that can travel through the blood to target organs in order to produce temporary changes in the way the cells function.
What is the difference between hormones and neurones
Hormones are slow acting
Neurones are fats acting
Which hormone controls blood sugar levels
Insulin
How does insulin reduce blood sugar
It travels through blood stream to its target organ the liver
It will increase the cells uptake of glucose
Increase the respiratory rate
And convert glucose into glycogen for storage
What mechanism is used to control blood glucose levels
Negative feedback
What is diabetes
A condition where people fail to produce enough insulin or fail to respond to it correctly.
What are symptoms of diabetes
High glucose levels
Glucose in urine
Excessive thirst
Lethargy
The frequent need to urinate
What are long term damages of diabetes if it is left untreated
Kidney damage, eye damage, stroke, and heart disease
What hormone is responsible for how much urine our kidneys produce
ADH
What does the ADH do
It allows the medulla of the kidneys to resorb more water into the blood.
What do plants grow towards the light
This would increase the rate of growth as more photosynthesis can occur. This is known as phototropism.
What hormone is responsible for phototropism
Auxin
How does the plant bend towards the light
The auxin gathers in the shaded side. The auxin elongates the cells making the shaded side longer causing it to bend towards the light.
What term describes the changes in the focusing of the lens
Accommodation
What is osmoregulation
The process in which the water levels in blood is controlled by kidneys and hormone ADH
What is type 1 diabetes
A condition which usually occurs in early life when the pancreas stops producing insulin, which then has to be taken as medication throughout life
What is type 2 diabetes
Progressive disease linked to lifestyle factors and obesity. Pancreas gradually produces less insulin.
