ciencias

The nervous system
Enables us to:
- What happens around us.
-respond to what happens, such as by making movements.
-coordinates all the organs and systems in the human body.
-the brain spinal cord and nerves form it.

The brain:
It is in the head, it’s protected by the bones of the skull.
a. The cerebrum: is the biggest structure of the brain, it controls all the voluntary actions.
Example:
- Riding a bicycle.
- Speaking.
- Eating.
The cerebrum also stores data and memories; it is involved in how it we feel, like when we are afraid or happy.
It also interprets information gathered by the sense organs.
b. Cerebellum: is collocated below the cerebrum. It coordinates movements and controls balance.
c. Brain steam: connects the brain with the spinal cord. The brain steam controls many process in the human body.
Example:
Controls heartbeats.
Movements we make when we breathe.
The spinal cord: is in the back, it goes from the top of the back bottom. It is protected by the vertebrae of the spinal column. The spinal cord is shaped like a cylinder.
-many nerves branch from the spinal cord.
-they go to the organs in the torso.
*stomach.
*limbs like the biceps.
- The spinal cord controls involuntary movements called reflexes.
Nerves:
-are shapes long fibers.
-they connect the brain and the spinal cord with the rest of the organs in the body.
-there are two types of nerves.
A. sensory nerves: carry information from the organs to the cerebrum and the spinal cord.
Example:
The auditory nerve carries information about sounds from the ear to the cerebrum.
B. motor nerves:
Carry information from the brain and the spinal cord to other organs. Motor nerves tell the body to make movements.
Example:
There are nerves that go from the spinal cord to the quadriceps muscle in the leg these nerves send the muscle an order to move so that you can walk.
Nerves coordinate all the functions of the body.
The skeletal – muscular system:
It is responsible for body movements. The skeleton and muscular systems form the skeletal – muscular system.
The skeleton:
All the bones in the human body form the skeleton; the skeleton has three important functions:
1. It sapports and gives shape to the body.
2. It protects the internal organs.
3. It provides a base for muscles. When muscles pull on the bones they are attached to, the bones move. That is how you can’t lift a arm, walk or make any other movements you want to.
Some bones have three functions at the same time.
Example:
Ribs:
Shape the body.
Protect the heart and lungs.
Provide a base for several muscles of the thorax.
The components of skeletal.
Cartilage: is flexible and softer than the bone. There is cartilage on the end of the, long bones, in the ears, the nose and on the ribs.
Bones: are very hard and resistant. They are made up of the tissue, and minerals like calcium. The minerals make the bones hard.
Joints: the place where two bones meet is called joint. There are two types of joints:
Fixed joints: the bones connected by fixed joints do not move.
Example: there are fixed joints between the bones in the skull.
Movable joints: the bones connected by movable joints can move. The wirts the union of the to move.
If there weren’t any joints, the skeletal would be rigid.
Muscular system:
Muscles and resistant and elastic. They are involved in the movement.
There are three types of muscles in your body.
Skeletal muscles: work together with bones. They are responsible for voluntary movements like chewing and walking.
Smoth muscles: form part of the organs inside the human body. The make involuntary movements.
For example:
The muscles of the esophagus are smoth muscles.
Cardiac muscle: is in the heart. This type of muscle never stops. It continues moving our entire lives. Cardiac muscle pumps blood with this movement.
Muscles contract and relax to produce movement. When a muscle contract, it gets smaller and pulls on the bone it is attached to. When the muscle relaxes it goes back to its original size. The bone then returns to it’s to initial position.
Movement: bones and muscles have to work together so that we can move. Muscles move when the nervous system send then order to move.
The nervous system coordinates the movements of the body in the following way.
1. The different sense organs gather information from the world around us.
2. The information passes to the sensory nerve in the sense organ. This nerve carries the information to the brain. When the information reaches the brain, we become aware of sounds, colors etc.
3. The brain interprets the information and orders a movement.
4. The motor nerves carry the brains orders to the muscles. When a muscle receives the order the move, it contracts. The muscle pull on the bone attached to, wich produces movement.

4.Asorpion:Asorpion takes place in the jejenum and the ileum of the small intestine during.Asorpion ,the nutrients formed during digestion pass into the bloodstream.