Homeostatis Flashcards
Definition for homeostasis
The regulation of the conditions inside your body to maintain a stable environment
In responses to changes both internally and externally
Why is homeostasis important
Because your cells need the right conditions in order to function properly and for enzyme action
What are the control systems that regulate internal environment
Nervous system
Hormonal system
What conditions need regulating in your internal environment
Body temperature
Blood glucose content
Water content
What are the control systems made up of to maintain a steady condition
Receptors Coordination centre Effectors Stimulus Control centre
What does the nervous system control
Temperature
Co2 levels
What does the endocrine (hormone) system control
Blood sugar level
Adrenaline
What is controlled by the nervous and endocrine system
Water
What is a stimulus
Change in environment
Where are coordination centres in the body
Brain
Pancreas
Spinal cord
What system does the body use to bring the body’s levels back to normal
Negative feedback
What’s the first 2 things that happen in negative feedback
The receptors in the body detect a stimulus (change in environment)
Then the receptor sends information to the coordination centre and that processes the info and organises a response
What the 3rd and 4th thing that happens in negative feedback
The effectors then produce a response which counteracts the change and restores the optimum level
The effectors will carry on producing the responses for as long as stimulated by the coordination centre
What is the nervous system made up of
The central nervous system
Sensory neurons
Motor neuronses
Effectors
What are sensory Nuerons
Neurons that carry information as electrical impulses from receptors to cns
What are motor neurons
Nuerons that carry electrical impulses from cns to effectors
What are effectors
All muscles and glands which respond to nervous impulses
What are the 3 main types of receptors
Taste on tongue
Sound in ears
Smell in nose
What’s a complex receptor
Retina on the eye is made up of many light receptors
How do the muscles and glands act differently when responding to nervous impulse
The muscles contract
The glands secrete hormones
Give the order of how the nervous system works
Stimulus Receptor Sensory Nuerone CNS Motor nuerone Effector Response
What do synapses do
Connect neurones or the connection between two neurones
Define what a reflex is
A rapid automatic response to certain stimuli that don’t involve the conscious part of the brain
Give an example of a reflex
Pupils automatically get smaller when a bright light is shined on you
What is the passage in a reflex called
The reflex arc
What type of nuerones are in a reflex
Sensory neutron
Relay nuerone
Motor nuerones
Order of first three things that happen in a reflex
If bee stung finger
Bee stings so stimulation of pain receptors
Impulses then travel along sensory nuerone
A synapse happens between sensory neurons and relay nuerone and the impulses are passed along relay
What happens in the last 2 things of a reflex
Via a synapse, impulses travel along a motor nuerone
From motor nuerone they go to effector which is the muscle and it the contracts
What test can you use to measure reaction time
The ruler drop test
Using a computer
What variables need to be controlled in the ruler drop test
Same person catching ruler
Same hand acting ruler
Same height ruler dropped at
Which test is better to record reaction time
Ruler drop or computer
Computer because it’s more accurate and precise
It also removes possibility of human error
Sugar regulation
What are glucose
A sugar released when food is digested
What is gylcogen
A long chain of carbohydrate and is made of stored glucose
What is glucagon
A hormone used to release glucose from stored glycogen
What is insulin
A hormone used to reduce blood glucose
What does the Brain do
Controls complex behaviour
It has billions of connections nuerones and has different regions to carry out different functions
What are the 3different regions of the brain
Cerebral cortex > conciousness
Cerebellum > muscle coordination
Medulla oblongata > unconscious activity
S
What 3 ways do the scientists study the brain
Pateients with brain damage
Electrically stimulating the brain
MRI scans
The eye
What’s the sclera
The tough supporting wall do the eye
The eye
What’s the cornea
Transparent out layer found at front of eye
Refracts light into eye
The eye
What’s the iris
Contains muscles that allows it to contract the diameter of the pupil
So how much light entered the eye
The eye what’s the lenses
Focuses light into the retina
The eye
What is the shape of the lens controlled by
The ciliary muscles & suspensory ligaments
The eye
What does the optic nerve do
Carries impulses from the receptors on the retina to brain
The eye
What happens when bright light is shon on the eye
A reflex is triggered
The circular muscle sin iris contract and the radial muscles relax reducing the amount of light that can enter
The opposite process happens in dim light
What’s the term used to explain how the eye focuses light on the retina
Accommodation
The eye
What happens in the ye when looking at close objects
Ciliary muscles tighten
Suspensory ligaments relax
Lens becomes fat and more curved
The eye
What happens when the eye looks at distant objects
Ciliary muscles relax
Suspensory ligaments tighten
Lens becomes thin
