Topic 5 - Homeostasis and Response Flashcards
What is homeostasis?
Maintenance of a constant internal environment
What is homeostasis needed for?
Enzyme action and cell function
Three things which homeostasis controls?
Blood Glucose Concentration
Body Temperature
Water Levels
What do all control systems have?
Receptors - Cells that detect stimuli
Coordination Centres - Process information received from receptors
Effectors - Muscle of gland which carry out responses accordingly
Steps on how the nervous system reacts accordingly to a stimuli?
Receptor cells convert stimulus into an electrical impulse
Electrical impulse travels along sensory neurons to the CNS
Information is processed at the CNS and appropriate response is coordinated sending electrical impulse via the motor neurone back to the effectors
The effectors carry out the response
What are reflexes?
Automatic response which take place before you have time to think
Function of the cerebellum?
Controls movement of muscles, rounded structure towards the back of your brain
What are synapses?
Gaps between two neurones
Reflex arc
Stimulus detected by receptors
Impulses sent along sensory neuron
CNS passes to relay neuron
Impulses sent along a motor neuron
Impulse reaches an effector and results in appropriate response
Steps on how synapse pass on information
When impulse reaches the end of the first neuron a chemical is released into the synapse
This chemical diffuses across the synapse
When the chemical reaches the second neuron, it triggers the impulse to begin again in the next neuron
Function of the Cerebral Cortex?
Controls consciousness, intelligence, memory and language and is the outer part of your brain
Different components of the brain
Cerebral Cortex
Cerebellum
Medulla
What a reaction time?
Time taken to respond to a stimuli
Function of the medulla?
Controls unconscious actions such as breathing and heart rate; Found in the brain stem in front of the cerebellum
Ways neuroscientists can map out the regions in the brain?
Studying patients with brain damage
Electrically stimulating different areas of the brain
Use MRI
Why is investigating the brain function and treating brain damage difficult?
Is complex and delicate
Easily Damaged
Drugs given to treat diseases cannot always reach the brain due to membranes surrounding
It is not fully understood what part of the brain does what
How can studying a patient with brain damage give us a better understand of the brain?
By seeing the effects on an individual following the damages on the certain part of the brain
How can electrically stimulating the brain give us a better understanding of the brain?
Passing electrodes in the brain damage certain areas providing information on the role of the area
How can MRI scans give us a better understanding of the brain?
Magnetic response can be used to create an image of the brain and can show which part of a brain is affected by a tumour
Whats the retina and the function?
Layer of light sensitive cells at the back of the eye. When light hits these are stimulated and impulses are sent to the brain to create an image
Function of the optic nerve?
Nerve that leaves the eye to the brain. Carries impulses from the retina to the brain
Function of sclera?
White outer layer, which supports structures inside the eyes. Strong to prevent damage to the eye
Function of the cornea?
See through layer at the front of the eye. Allows light through and curved surface bends light to the retina
Function of the iris?
Muscles which surround the pupil. Contract or relax to alter size of pupil
Function of Ciliary muscles and Suspensory Muscles?
Hold the lens in place. They control its shape
Process of accommodation to focus on a distant object?
Ciliary Muscles Relax
Suspensory Ligaments tighten
Lens becomes thinner - light is refracted less
What happens to the iris during bright and dim light?
Bright Light- Circular Muscles contract and radial muscles relax to prevent damage to the retina
Dim Light - Circular muscles relax and radial muscles contract so more light can enter and creating a better image
What’s Long sightedness called, and reason?
Hyperopia
Lens is too flat, so not enough light can be refracted
Process of accommodation to focus on a near object?
Ciliary Muscles contract
Suspensory ligaments loosen
Lens becomes thicker and more curved - light is refracted more
What’s short sightedness called, and reason?
Myopia where the lens is too curved so distant objects appear blurry
