The human nervous system Flashcards
Explain the process of the reflex arc
- The receptor detects the stimulus
- Electrical impulses are generated and they pass along the sensory neurone (the first neurone of the refelx arc
- The electrical impulse reaches a synapse where neurotransmitters are generated and they diffuse along the synapse gap from an area of high to low concentration.
- Then electrical impulses are generated and are transmitted along the relay neurone in the spinal chord in the Central Nervous System.
- The electrical impulses travel to the motor neurone which is connected to an effector, a muscle which contracts/gland that secretes a hormone in response
Name the different adaptations of a neurone
- Has many drendites
- Has a long axon
- Has a fatty myeli sheath layer insulating axon
aslo has nucleus in the cell body
What is the myelin sheath made out of?
Fatty layer
What is the function of the myelin sheath?
The myelin sheath is a fatty layer which insulates the axon on the neurone.
This prevents the transmission of electrical energy to the surroundings, thus speeding up the transmission of electrical impulses along the neurone.
Explain how electrical impulses are transmitted across a synapse
- Electrical impulses travel along the neurone and aproach the axon terminal
- At theaxon terminal, neurotrnasmitters are generated
- These neurotransmitters diffuse along the synapse from an area of high to low concentration
- The neurotransmitters bind to the dendrites of the next neurone
- At the dendrites, an electrical impulse is generated and it travels along the new neurone.
Where is the nucleus found in a neurone?
In the cell body
Neurones have many
d_ _ _ _ _ _ _ _
fill in the blank
Neurones have many dendrites
What is the gap between two neurones called?
The synapse
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
cross the synapse by diffusion
fill in the blank
Neurotransmitters
cross the synapse by diffusion
What is generated after the neurotransmitters bind to the dendrites on the next neurone?
Electrical impulses are generated
Electrical impulses are transmitted through a what?
Neurone
What two things is the sensory neurone connected to?
Relay neurone
Sensory receptors
What two things are connected to the motor neurone?
Relay neurone
Effector
What are the two things that effectors can be?
Muscle
Gland
When stimulated, what happens to an effector if it is a muscle?
The muscle contracts
When stimulated, what happens to an effector if it is a gland?
It secretes hormones
Name the Receptor cells in the human body
- Eyes (see)
- Nose (smell)
- Tongue (taste)
-
Ears (sound)
5.Pain receptors in skin (touch)
Basically, the 5 SENSES
What is a receptor cell stimulated by?
A stimulus
Give an example of a stimulus
Heat
What is immediately generated at receptor cells?
Electrical impulses
What is the first neurone in the reflex arc?
The sensory neurone
What is the second neurone of the reflex arc?
The relay neurone
Where is the relay neurone found?
In the spinal chord in the Central Nervous System
Do reflexes involve the brain?
No
Are reflexes rapid or slow?
Rapid
Are reflexes consious or unconscious
Unconscious
What is the final neurone of the reflex arc?
The motor neurone
Why is the reflex arc important?
The reflex arc birngs a rapid and automatic response to a stimulus. This is important as it helps us avoid danger or harm
What is the function of the relay neurone?
Transfers electrical impulses from the sensory neurone to the motor neurone
What is the function of the sensory neurone?
To transmit electrical impulses from the receptor to the relay neurone
What is the function of the motor neurone?
To transmit electrical impulses from the relay neurone to the effector
What is the function of the effector
The effector converts electrical impulses into an action,
e.g. muscle contraction or hormone secretion
