The Nervous System Flashcards
Multicellular organism cells need to be able to …
What happened when they evolved ?
Communicate with each other so the organism can respond to stimuli. As multicellular organisms evolved they developed nervous and hormonal communication systems.
What is the CNS? How is this connected to receptors and effectors?
The central nervous system. This consists of the brain and spinal cord in vertebrates. The CNS is connected to the body by motor and sensory neurone that make up the peripheral nervous system.
What are effectors?
All your muscles and glands that react to nervous impulses.
What do sensory neurones and motor neurones do?
Sensory neurones- carry impulses from the receptors to the CNS.
Motor neurones - carry impulses from the CNS to the effectors.
Receptors are cells that…
They can form…
Give an example.
Cells that detect stimuli. These can form part of larger complex organs such as the retina of the eye which is covered in light receptor cells.
Effectors respond to…
They bring about a…
Respond to nervous impulses and bring about a change. These can form complex organs.
Name the types of effectors….
Muscle cells - these make up muscles.
Hormone secreting cells - these are found in glands, such as cells that secrete ADH which are found in the pituitary gland.
The CNS is a…
Processing centre.
A neurone consists of…
The cell body. The impulse is carried along the axon, which is an elongated cytoplasm drawn out in a long fibre and surrounded by membrane. The insulating sheet speeds up transmission.
Electrical impulses are fast but…
Why? Give an example?
Fast but short lived as they carry information around the body so quickly, ie- touching something hot and then pulling your hand away.
Hormones are used to…
They are produced in…
The responses they cause are….
carry information around the body. These are produced in glands and travel around in the blood. The responses they cause are brought about more slowly and they are longer lasting.
How does ectasy work?
Ecstasy blocks receptor sites, on the membranes of motor neurones, where the transmitter chemical serotonin is taken up. This increases the concentration as the serotonin can’t be removed, enhancing the mood as a result.
Serotonin affects…
Pain, mood, aggression, and appetite.
Organisms need to respond to stimuli in order to…
Survive.
What do beta blockers do?
The block the receptor sites on heart muscle cells, preventing impulses from passing to the heart.
