Reflexes and Hormones Flashcards
(36 cards)
What is a stimulus?
A change in your environment that you react to
What are the five different sensory organs?
What do these contain?
Eyes ears nose tongue skin Receptors
What are receptors?
What do they do?
Groups of cells that are sensitive to a stimulus
Change stimulus energy into electrical impulses
What could a stimulus be? (guess 3)
Light sound touch pressure chemical change in position or temp
The eye is the …. ….
This contains the ….. ……
sense organ
light receptors
What is the central nervous system?
What does it consist of?
Where all the info from the sense organs is sent and reflexes and actions are coordinated
The brain and spinal cord only
What do neurons do?
What is a neuron?
Transmit the information (electrical impulses) very quickly to and from the CNS
A nerve cell
What does the CNS do after it has received an electrical impulse from a sense organ?
Send electrical impulses (instructions) to the effectors (muscles and glands) which respond accordingly.
Sense organ: Eyes
The receptors and what they’re sensitive to: (+ what’s in the cells)
Light receptors
Sensitive to light. The cells have a nucleus, cytoplasm and cell membrane
Sense organ: Ears
The receptors and what they’re sensitive to: (2)
Sound - sensitive to sound
Also balance receptors, sensitive to position
Sense organ: Nose
The receptors and what they’re sensitive to: (2)
Small receptors - sensitive to chemical stimuli
Sense organ: Tongue
The receptors and what they’re sensitive to: (2)
Taste receptors - sensitive to bitter and sweet - and other tastes - chemical stimuli
Sense organ: Skin
The receptors and what they’re sensitive to: (2)
Sensitive to touch
Pressure, pain and temp change
What do sensory neurons do?
Nerve cells that carry signals as electrical impulses from the receptors in the sensory organs to the CNS
What do relay neurons do?
These nerve cells carry signals from the sensory neurons through the CNS to the motor neurons
What do motor neurons do?
Carry signals from the relay neurons in the CNS to the effectors
What do the effectors do?
Muscles and glands are effectors and respond in different ways - muscles contract in response to nervous impulses and glands secrete hormones.
What are synapses?
The connection between two neurons
What happens to the nerve signal at a synapse?
It’s transferred by chemicals which diffuse over the gap, these then set off new electrical signals in the next neuron
What are reflexes?
What can they reduce?
Automatic responses to certain stimuli
The chances of being injured
What are two examples of automatic reflexes?
A bright light in an eye - the pupils immediately go smaller to stop so much light getting into the eye so it doesn’t get damaged
When shocked the body releases the adrenaline hormone
Where do the neurons in the reflex arc go through?
The spinal cord or the unconscious part of the brain
What happens when a stimulus is detected by a receptor?
Impulses are sent along the sensory neuron to the CNS
What happens when the impulse reaches the synapse between the sensory neuron and the relay neuron?
They trigger chemicals to be released and these cause impulses to be sent along the relay neuron
