glossary

GLOSSARY SENSITIVITY

1. **SENSITIVITY**: Through sensitivity, we respond to changes in the external environment. Various organs and systems are involved. First, the sense organs capture the information. Second, the brain receives and interprets this information and decides how to act. Third, the muscles receives orders from the brain, and they move the body.



2. **SENSE ORGANS**: They obtain the information from the external environment. Sense organs have special cells, receptor cells, that can detect stimuli (light, sound, taste, smell and pressure) from the environment.

3. **LOCOMOTOR SYSTEM**: Is formed by the muscles and the bones. The function of the locomotor system consists in producing movement when de muscles and the bones work together. The bones receive orders from the brain or the spinal cord. When the muscle receives an order, it contracts pulling the bones to which it is joined. When the order stops, the muscles relax and regains its original size. The bones return to their initial positions.



4. **NERVOUS SYSTEM**: Is formed of nervous tissue. Nervous tissue is found in every part of the body and its made up of one kind of cells called neurons. The nervous system is formed by the central nervous system and the peripheral nervous system.

5. **INTERNAL COORDINATION**: is the function of our bodies that controls our internal environments. It is part of the sensitivity and the nervous system carries out internal coordination as well as our movement.

6. **NERVES**: a whitish fibre or bundle of fibres in the body that transmits impulses of sensation to the brain or spinal cord, and impulses from these to the muscles and organs. Nerves are made up of neurons.



7.**SENSORY NERVES**: carry information from the sense organs to the central nervous system.

8. **MOTOR NERVES**: carry orders from the central nervous system to the muscles and the organs.

9.**CENTRAL NERVOUS SYSTEM**: has two parts: the brain and the spinal cord. b. The **Spinal cord** goes from the brain to the botom of the spine. The spinal cord is protected by the spinal column.
 * 1) The **brain** is the control centre of the body. It is protected by the cranium. It is the most important organ, and has three parts:
 * 2) the **cerebrum**: control our voluntary actions and our emotions, and stores memory
 * 3) the **cerebellum** co-ordinates movements and balance in our body
 * 4) the **brain stem** regulates the organ activity

10. **PERIPHERIAL NERVOUS SYSTEM**: is formed by the nerves. Is the nervous system outside the brain and spinal cord.

11. **MOVEMENT:** act, process or result of moving. Many are voluntary such as writing, other we do involuntarily.

12. **VOLUNTARY MOVEMENT**: are those that we choose to make consciously. Orders take place in the brain and arrive to the muscles through the nerves. The brain interprets information from the sense organs and other information such as memories.

13. **REFLEX MOVEMENT**: are those movements that happen automatically, without a conscious order from the brain. When they happen, we are only aware of them after they have happen. Many reflexes are there to protect us from danger situations. In many reflexes the brain is not involved. The spinal cord receives information and sends an order of movement.

14. **ENDOCRINE SYSTEM**: is formed by organs called endocrine glands that make hormones. These are substances that act like messengers, they transmit orders. The endocrine system reacts much more slowly than the nervous system, also, can affect many organs at once. 15. **ENDOCRINE GLANDS**: the pituitary gland, found in the brain, produces hormones that direct the activity of other endocrine glands, also produces the hormone that controls growth. The thyroid helps us with nutrients. The pancreas produces insulin that regulates the amount of sugar circulating in our blood. The ovaries and testicles produce sex hormones that determine masculine and feminine sexual characteristics. 16. **NEURONS**: have a complex shape, are a type of cell with three parts.
 * Body: contains the nucleus and organelles
 * Dendrites: are branched structures, with this structures neurons receive information from the sense organs or from other neurons
 * Axon: transmits information to other neurons and sends orders to organs. Axon run beside other axons to form nerves.



17. **SENSE ORGANS AND SENSES**: sense organs collect information from the environment and send it to the brain. They are: ear, eye, tongue, nose and skin.



18. ** SENSE ORGANS: **Each of the senses' main parts in the images below:

19. **INVOLUNTARY MUSCLES**: are part of many organs in our body. They are controlled by the brain stem and work automatically.