Thursday, January 26, 2012

2.82 Communication


Describe how responses can be controlled by nervous or by hormonal communication and understand the differences between the two systems

1. Nervous system
The cell body of the nerve would be connected to the spine
The other end, synaptic knob, of the nerve would be connected to the effector, which is most likely a muscle
The electrical impulse, or nerve impulse, is carried along inside the nerve down the axon from the cell body to the synaptic knob, which can be a meter long (and it is a single cell).
In mammals, the axon can be surrounded by another kind of cell known as the schwann cell. It contains a great deal of fats and formed a myelin sheath, which helps increase the speed of nerve conduction (for information to be passed).

2. Hormone - Endocrine system
Hormones can be proteins or steroids.
Made in the endocrine glands
Travel in blood
Effect the target tissue

Endocrine gland produces chemical known as hormone. 
Eg) adrenal gland which produces adrenaline
The hormone is secreted into the blood and travels through the stream and arrive at target tissue/ organ that will have an effect on.
Hormones can have multiple target and brings about multiple effects.

Nerves transfer impulses much faster than hormone does.

The picture only shows a motor nerve. 

No comments:

Post a Comment