Effects and Response of the human body Flashcards
Name the 5 sensory organs.
Eyes, Ears,Nose,Tongue,Skin.
What is the meaning of the word stimulus?
A stimulus is a change in the environment that you may need to react to.
What do all sensory organs have to detect stimulus?What do these things do?
Receptors are cells that are sensitive to stimulus, they change stimulus energy into electrical impulses.
Describe a sensory neurone.
The sensory neurones are the nerve cells that carry electrical impulses from the receptor to the CNS.
Describe a relay neurone.
The relay neurons are nerve cells that carry signals from the sensory neurons to the motor neurons.
Describe a motor neurone.
Motor neurones are the nerve cells that carry signals from the CNS to the effector muscles or glans.
What is synapse?
The gap between two neurones.
How do signals get across the synapse?
The nerve signals are transferred by chemicals which diffuse across the gap. The chemicals then set off the new electrical signal in the next neurone.
Describe reflexes.
Reflexes are automatic responses to stimuli: they can reduce injury.
What is the reflex arc?
Stimulus-Receptor-Sensory neurone-Relay neurone-Motor neurone-Effector-Response.
Describe a hormone.
Hormones are chemicals released directly in the blood.
Compare both nerves and hormones.
Nerves. Very fast, act for a short time, act on a very precise area. Hormones. Slower action, act for a long time, act in a more general way.
How does the pituitary gland work in the menstral cycle?
It produces both FSH and LH.
What do the ovaries do in the menstral cycle?
They produce oestrogen.
What are the four stages of the menstral cycle?
1) Day 1 is bleeding, 2) from day 4-14 the uterus lining builds up ready to recieve fertilised egg. 3) Egg is released at day 14. 4) The wall is maintained until day 28.
