Nerves And Sensitivity Flashcards
What is a coordinated response?
Being able to make things happen in different parts of the body and at the right time
Which two systems do animals use to coordinate responses?
The nervous system The endocrine (hormone) system
A coordinated response requires 3 things….
Stimulus Receptor Effector
What is a stimulus?
Change in animals surroundings
What is a receptor?
Organ that detects the change e.g. Your eye
What is the effector?
Muscles are the effectors that respond and make something happen
What energy change takes place in the eye receptor?
Light into electrical nerve impulses
What energy change takes place in the ear receptor?
Sound into electrical nerve impulses
What energy changes take place in the tongue receptor?
Chemical to electrical nerve impulses
What energy change takes place in the nose receptor?
Chemical to electrical nerve impulses
What energy changes take place in the touch receptors in skin?
Pressure into electrical nerve impulses
What energy changes take place in the temperature receptors in skin?
Heat into electrical nerve impulses
Name the 2 main parts of the central nervous system
Brain and spinal cord
Which part of the nervous system contains all other nerves which send impulses to all effectors (muscles)
Peripheral nervous system
What does the central nervous system do?
Coordinates all nervous responses such as moving or reflexes
Name the 3 types of neurone.
Sensory neurones - from receptors Relay neurones - to central nervous system Motor neurones - to the effectors (muscles)
Name the parts of a motor neurone
- Nucleus
- Dendrite
- Cell body
- Axon
- Myelin sheath
What does the myelin sheath do?
Insulates the axon and speeds up the transmission of the impulse.
What does the dendrite do?
Tree like projections which connect to many different neurones
What is a reflex?
Automatic actions which do not involve the brain They are very fast and involve the three neurones Impulse moves from receptor to effector in a reflex arc
Describe how a reflex arc response works. Clue: touching a hot plate
- Receptor detects stimulus
- Sends impulse along a sensory neurone
- Sensory neurone passes impulse across the spinal cord to the relay neurone
- Relay neurone passes the impulse to the motor neurone
- Motor neurone causes the effector to contract
- Gap between neurones is called a synapse
What is a synapse
A junction between two nerve cells
