B10 Nervous System Flashcards
What is homeostatis?
Homeostatis is the process of keeping everything constant inside your body
What is your internal environment?
The conditions inside your body are known as your internal environment
What are some things controlled in homeostatis?
- Body tempratute
- Water levels
- Glucose concentration in blood
Why can too high water levels in your body be dangerous?
Too much water can cause your cells to burst due to osmosis
What is the order of the control systems in homeostatis?
1) The change in the bodys environment is called the stimulus
2) Special ‘receptor’ cells detect the stimulus
3) The brain processes the information of the stimulus and sends a signal to make the response happen
4) The effectors bring about the response
What does the nervous system do?
It controls all the actions that our body makes
What body parts does the central nervous system (CNS) contain?
The brain and the spinal cord
What does the sensory neurone do?
The sensory neurone is connected to the receptor and carries the message to the CNS
What does the motor neurone do?
The motoer neurone carries messages from the CNS to the effector
How does information pass from the receptor to the CNS and from the CNS to the effector?
Information passes along nerve cells called neurones as eletrical impulses to the central nervous system
What is the order of the nervous system from a stimulus —> the response?
Stimulus —> Receptor —> Sensory Neurone —> CNS —> Motor Neurone —> Effector —> Response
What are reflex actions?
Reflex actions are automatic actions which we do involuntary (without thinking)
What causes us too not think during a reflex action?
Messages bypass the brain so the stimulus can reach the response faster
What is different between a reflex action and a normal action in terms of the journey from the stimulus —> the response?
Rather than going from the sensory neurone too the CNS the message goes from the:
sensory neurone —> the relay neurone —> motor neurone
What is a synapse?
A synapse is the gap where 2 neurones connect
What are neurotransmitters?
Neurotransmitters are chemicals that are released at one end of a neurone to help the eletrical impulses cross the synapse
What are neurotransmitters?
Neurotransmitters are chemicals that are released at one end of a neurone to help the eletrical impulses cross the synapse
What are the 5 different parts of the brain?
- The cerebral cortex
- The cerebellum
- The hypothalamus
- The medulla
- The pituitary gland
What is the cerebral cortex and what does it do?
The cerebral cortex largest part of the brain (the pink ‘mushy’ bit) and it is involved in consciousness, memory, language and intelligence
What is the cerebellum and what does it do?
The cerebellum is the second largest part of the brain (below the cerebral cortex) and it coordinates muscle activity and balance
What is the medulla and what does it do?
The medulla is the part of the brainstem (bottom stem of the brain) and it is involved in unconscious activites
What is the hypothalamus and what does it do?
The hypothalamus is the small area in the middle of the brain and it has many functions, including control of temprature
What is the pituitary gland and what does it do?
The pituitary gland is a small gland beneath the hypothalamus and it produces many different hormones too help coordinate and control the body systems
Why are some people short/long sighted?
As the light that enters the eye is concentrated infront of or behind the retina
What is accomodation in the eye?
The eyes ability to change the shape of the lens to refract the light so it is concentrated on the retina
What is the first structure that light will hit when entering the eye?
The cornea
Why is the cornea completely transparent?
To allow all the light too pass through
Why do we need the cornea?
It allows the light too refract when entering the eye
What is the iris?
The coloured bit if your eye, surrounding the pupil
What is the pupil?
The black structure that is being surrounded by the iris
What is behind the iris and pupil?
The lens
What is behind the iris and pupil?
The lens
What is similar about the cornea and the lens?
They both refract the light
Why can the lens change shape?
So it can control how strongly it refracts the light so the light ends up concentrating perfectly on the retina at the back of the eye
Why can the lens change shape?
So it can control how strongly it refracts the light so the light ends up concentrating perfectly on the retina at the back of the eye
What are the 2 different types of receptor cells that the retina is made up of?
Cone cells which allow us too see colour
Rod cells which allow us to see in black and white
What are the 2 different types of receptor cells that the retina is made up of?
Cone cells which allow us too see colour
Rod cells which allow us to see in black and white
Why can u not see colours when it is dark?
As it is only your rod cells which are working
What is the fovea?
A special spot on the retina where only cone cells are working
What is the optic nerve and what does it do?
The optic nerve takes all of the impulses generated by the receptor cells and transmits them too the brain
What happens too the pupil when in bright light conditions?
The pupil constricts (becomes smaller)
What happens too the pupil when in low light conditions?
The pupil dilates (becomes larger)
What are the 2 muscles inside the iris?
- The circular muscles on the inside
- The radial muscles on the outside
What do the suspensory ligaments do?
- They control the shape of the lens
- They attach the lens too the ciliary muscles
What happens to the lens when looking at a close object?
It becomes shorter and thicker
What happens to the lens when looking at a far away object?
The lens becomes taller becomes thinner
What do the ciliary muscles do when looking at a distant object?
They relax which means the lens is more stretched out
What do the ciliary muscles do when looking at a nearby object?
They contract which lets the lens return to its natural shorter and fatter shape too refract the light more
