B.10 Flashcards
Homeostasis
The regulation of the internal conditions of a cell or organism to maintain optimum conditions for functions, in response to internal and external changes.
What does homeostasis do?
Maintaining optimal conditions for enzyme action and all cell functions.
Types of homeostasis in the human body.
Control of blood glucose concentration, body temperature and water levels.
What is in control systems
Receptors, coordination centres and effectors.
Receptors
Cells that detect changes in the internal or external environment and they are called stimuli. Receptors are apart of nervous or the hormonal control system.
Coordination centres
Areas that receive and process the information from the receptors. They send out signals and coordinate the response of the body. They include the brain, hormonal system, the spinal chord and more organs such as the pancreas.
Effectors
Muscles or glands that bring about responses to the stimulus that has been received. These responses restore conditions to the optimal level.
How the nervous system works
It uses electrical impulses to enables you to react quickly to your surroundings and coordinate your behaviour.
Sensory neurones
The cell that carries impulses from your sense organs to your CNS
Motor neurones
They carry impulses from your CNS to the rest of tour body to make the right parts of your body work.
CNS
Central nervous system is made up of the brain and the spinal chord.
Reflexives
Automatic movements to help your body
What do the reflexes involve?
Sensory, relay and motor neurones.
Reflex actions
Control everyday bodily functions, such as breathing and digestion, and help you to avoid danger
Reflex arc
Stimulus, receptor, sensory neurone, relay neurone, motor neurone, effector and then the response.
The brain
Billions of interconnected neurones that control complex behaviour.
Cerebral cortex
Helps you with Consciousness, intelligence, memory and language.
Cerebellum
Helps you with your coordination skills, memory and balance.
Medulla
Helps with unconscious acts such as controlling gut movement, controlling your heart beat and breathing.
How to help a damaged brain
You can either use a MRI scanner that scans the brain and shows you the area that isn’t working as it should.
Or by using a electrically stimulating different areas of the brain ( but this can lead to brain damage in other areas of the brain if not careful).
The eye
A sense organ containing receptors in the retina that are sensitive to light intensity and colour.
Sclera
A tough outer layer that has a transparent region at the front called the cornea that lets light in and refract light towards the retina.
Iris
Controls the size of the pupil and the amount of light entering the eye.
Ciliary muscle and suspensory ligaments
Change the shape of the lens to fine focus lights on to the retina
Optic nerve
Carries impulses from the retina to the brain.
Cornea
Controls the amount of light entering the eye
Pupil
Absorbs the light entering the eye and sends a good amount towards to retina not to damage it.
The retina
Converts light energy into impulses that then go to the optic nerve
Accommodation
The process of changing the shape of the lens of the eye to focus on near or distant objects.
Close objects (long sightedness)(Hyperopia)
Can see clearly distant objects, but close objects looked blurred and this results the lens to be too flat and thin or be too short for an eyeball and this means the lens doesn’t refract the rays of light enough.
Long objects (short sightedness) (Myopia)
Can see close objects in clear focus, but distant objects looked blurred and this is due to the light being in front of the retina so the images that land on the retina are out of focus and blurry.
How to help these problems
Spectacle lenses, laser surgery, hard or soft contact lenses and replacement lenses in the eye.
Concave lenses
Used to correct short sightedness.
Convex lenses
Fixes long sightedness problems.
