B10 - Nervous System Flashcards
What is your internal environment?
The conditions inside your body
Why cant your internal environment change?
Your organs and reactions wont work
What happens to your enzymes when your body is too hot?
They will denature and the activesite wont work
What happens to your enzymes when your body is too cold?
Enzymes will slow down so less reactions will take place
What is Homeostasis?
the regulation of internal conditions inside cells or organisms, to create the optimum conditions for biological function
What are three things that homeostasis controls?
Temperature
Water levels
Glucose concentration in the blood
Why is homeostasis important?
You need fhe right conditions for enzyme action
What are 2 automatic control systems in your body?
The nervous system
The endocrine system
What is the negative feedback mechanism?
Where automatic control systems keep your internal environment stable
Where is the Central Nervous System (CNS) located?
the brain and spinal cord only
What are sensory neurones?
Neurones that carry information as elctrical impulses from the receptors to the CNS
What are the effectors?
All your muscles and glands which respond to nervous impulses
What do receptor cells detect?
The stimuli
Name 3 different types of receptors and where they would be located?
Taste receptors on the tounge
Sound receptors in the ears
Light receptors in the eye
What do effectors do?
They respond to nervous impulses and bring about a change
What is a ‘stimulus’?
A change in environment
What is the function of the central nervous system(CNS)?
The co-ordination centre. It recieves information from the receptors and then co-ordinates a response
What are Motor Neurones?
Neurones that carry electrical impulses from ghr CNS to effectors
What is a synapse?
The connection between two neurones
What are reflexes?
Rapid, automatic responses to certain stimuli that dont involve the conscious part of the brain
How does the Automatic control system work when your body is in a cold environment?
Low temperature stimulus will be detected by skin receptors
They send impulses to the CNS
They interpret the informations and then send another signal to the effectors (muscles)
Msucles shiver so we eventually warm up
How does the Automatic control system work when your your eyes are faced with bright light?
Bright light stimulus will be detected by light receptors in the retina
They send impulses to the CNS
They interpret the informations and then send another signal to the effectors (muscles)
Iris muscles contract to make the pupils smaller
What is the simple function of a nerve cell?
To carry eletrical impulses from one point to another
How is information passed from one nerve cell to another?
When an electrical impulse reaches the end of a nerve, it releases chemicals which diffuses to the next nerve cell that triggers another electrical impulse
What are the two main types of nerve cells?
Sensory neurones
Motor neurones
What is the order messages are sent through the body?
Stimuli - receptors - sensory neurones - CNS - Motor Neurones - effectors
What is the order messages are sent through the body?
Stimuli - receptors - sensory neurones - CNS - Motor Neurones - effectors
What is a relflex arc?
A nerve pathway that happens during a reflex
What is the difference between information passages with a reflex arc and a normal nervous system response?
Reflec arc uses a relay neurone in the CNS to connect the sensory snd motor neurones
What is reaction time?
How long it takes you to respond to a stimulus
What drug can speed up a persons reaction time?
Caffeine
Explain the experiment of testing reaction time
Sit with arm resting at the edge of a table and look straight while someone drops the ruler between your fingers at 0cm
Repeat this with a caffeinated drink
What are some variables you must control in the reaction time experiment?
Same person
Same hand
Same initial height of ruler
What is the brain made up of?
Billions of interconnected neurones
Whats another word for neurones?
Nerve cells
What two things make up the central nervous system?
The brain and spinal cord
What does the term “cross-section” mean when looking at something?
It has been sliced in the middle to see inside
Where is the cerebral crotex in our brain and what is is responsible for?
The outer wrinkly bit
responsible for consciousness, intelligence, memory and language
The cerebral cortex is split into two halves. What do we call these?
Hemispheres
What does the left hemisphere of our cerebral cortex control?
What does the right hemisphere of our cerebral cortex control?
Left - controls the muscles on the right side of our body
Right - controls the muscles on the left side of our body
Where is the cerebellum in our brain and what is is responsible for?
The back of the brain
responsible for balance and muscle co-ordination
Where is the Medulla in our brain and what is is responsible for?
At the bottom within the brainstem
responsible for things you dont need to think about like breathing and heart beat
What are the three ways scientists study the brain?
Studying patients with brain damage
Electrically srimulating parts of the brain
MRI scans
Neuroscientists study the brain by studying patients with brain damage. How?
Seeing which damaged parts of the brain damage body function.
Neuroscientists study the brain by electrically stimulatings parts of it. How?
Using a tiny electrode to zap parts of the brain. Can see which areas zapped can affect the body
What are MRI scans?
A machine that produces a detailed pictures of the brains activity when it does something. Like listening to music
Why is treating the brain so difficult?
High risk of damage
Very complex
What is the Sclera in an eye?
The white and tough part that supports the eye
What is the cornea of an eye?
The transparent outer layer found in the front of the eye. It refracts light into the eye
What is the Iris in an eye?
The coloured bit of an eye that contains muscles that control the diameter of the pupil
Why does the Iris contain muscles to control the diameter of the pupil?
To control how much light gets into the eye
Why is the cornea completely transparent?
To allow all the light to pass through
Since the cornera doesnt have any blood vessels, how does it get its oxygen?
from the outside air by diffusion
What does the Lens in an eye do?
Change shape to control how strongly it refracts the light onto the retina
What two types of receptor cells are in the retina and w
Cone cells
Rod cells
What are cone cells?
Cells that are sensitive to light so allow us to see colour
What are rod cells?
Cells that are more sensitive to light in the dark so allow us to see black and white
Why cant you see colour in the dark?
Only you rod cells are working
What is thr function of the optic nerve?
Carries impulses from the receptors on the retina to the brain
What is the iris relfex
A relflex that controls the size of your pupil
What is the name for a pupil that becomes smaller in the bright light conditions?
Constricted
What is the name for a pupil that becomes larger in the low light conditions?
Dilated
How does a pupil get smaller in bright light?
The circular muscles in the iris contract and the radial muscles relax
How does a pupil get bigger in low light?
The radial muscles contract and the circular muscles relax
What is ‘accomodation’ in terms of the eye?
A relflex that changes the refractive power of the lens
What happens to the cilary muscles and suspensory ligaments when you look at near objects?
The cilary muscle contract and the suspensory ligaments slacken
Why, when you look at near by objects, your cilary msucles contract and suspensory ligaments slacken?
So the lens can become curved to increase the amount it refracts light
What happens to the cilary muscles and suspensory ligaments when you look at distant objects?
Th ciliary muslces slacken and the suspensory ligaments contract
Why, when you look at distant by objects, your ciliary muscles relax and suspensory ligaments contract?
The lens becomes thin so it decreases the amount it refracts light
What are long sighted people unable to focus on?
Near objects
What are short sighted people unable to focus on?
Distant objects
If the lens is the wrong shape for a long sighted person, what happens?
Doesnt refract light enough
Eye ball is is too short
If the lens is the wrong shape for a short sighted person, what happens?
Refracts too much light
Eyeball is too long
What is the medical term for long-sightedness?
Hyperopia
What is the medical term for short-sightedness?
Myopia
What lens would a longsighted person wear and what lens would a shortsighted person wear?
Long - convex lens
Short - concave lens
What are three alternatives to glasses for someone who is long/short-sighted?
Contact lens
Laser eye surgery
Replacement eye surgery
What is the acronym CCSS when looking at near objects?
Ciliary muscles contract
Suspensory ligament slacken
What is the acronym CCRR when talkng about pupils getting smaller?
Circular muscles contract
Radial muscles relax
Which term describes the adjustment of focus from the distant object to the
near object?
Accomodation
