Controlling systems
All the parts of the body are interdependent and work together as
a unit. Two systems control the body cells: the nervous system and the endocrine system. Both systems transmit information from one part of thie body to another, but in different ways.
The nervous system
The nervous system transmits irnformation very quickly from one part of the body to another using nerve impulses. lt plays the role of a coordinating unit which responds to external and internal changes, stimuli, and helps the body to ad.apt to new conditions .
WARM UP
- How fast do neurons transmit information?Choose among the following:
a. 120 m/s
b. 150 m/s
c. 200 m/s
lt can be divided into the Central Nervous System (CNS) and the
Peripheral Nervous System1 (PNS).
The CNS consists of the brailll and the spinal cord, while the PNS is made up of the nerves connecting the brain and the spinai cord to other parts of the body, s:uch as the skin surface and the skeletal muscles.
The PNS is made up of two parts: the somatic and the autonomie nervous systems.
DO
1 Do you know why the peripheral nervous system is also called the sympathetic system?
The somatic nervous system consists of peripheral nerves that pick up sensory information from distant organs, like the limbs, and carry them to the CNS.
The autonomic nervous system controls the nerves of internal body organs over which humans have no conscious control. This includes heartbeat1, digestion, and unconscious breathing.
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1With the use of the blank verse, Shakeapeare tried to reproduce the human heartbeat.
The endocrine system
The endocrine system is a network of glands that make the hormones that help cells talk to each other. The hormones are secreted into the blood stream and circuiate from one gland to another in different parts of the body, transmitting information, although more slowly than the nervous system.
Endocrine glands are responsible for almost every celi, organ, and function of the body. Most glands have important functions like the pituitary gland, or hypophysis, which regulates a wide variety of metabolic processes essential to normai growth and homeostasis.
