Lesson 5 Human development
The nervous system.
It´s divided into two parts:
a) The central nervous system: It´s made up of the encephalon and the spinal cord:
- The encephalon is divided into three parts:
a) The brain: Makes decisions and generate orders
b) The cerebellum controls voluntary movements.
c) The brainstem: Controls automatic movements. It´s linked to the spinal cord.
The encephalon is protected by the skull and the meninges. There is a liquid called cerebrospinal liquid that protects the encephalon from injuries.
- The spinal cord: from the encephalon to the lower part of the back and transport information between the receptors, the encephalon and the effectors
b) The peripheral nervous system It´s made up of nerves that link the receptors to the central nervous system. Our nerves are divided into sensory nerves (that carry signals from receptors to the central nervous system) and the motor nerves ( that carry signals from the central nervous system to the effectors)
The Skeleton: Bones and Joints
The skeleton is formed by bones and joints. Joins are the conections between two bones. Our bones protect our organs and allow us to be right. Bones are pieces of hard tissue. They can be long (femur), short (vertebrae) or flat (pelvis). Joints can be Semi-mobile (like ribs or the spine) Fixed or Immovable (like the Skull) and Mobile Joints like the elbow.They are connected by ligaments. The joins are covered by protective tissue (cartilage) and lubricated by a liquid called synovial fluid.
The muscles
They are formed by muscles cells. They can contract or relax depending on the signals they receive. The muscles that belong to the locomotor system are attached to the skeleton by tendons. Other muscles are not attached to any bone like the heart.
Illneses of the nervous system
They can be:
- Injuries: When something hits your body.
- Psycological disorders: Can be caused by stress
- Degenerative illnesses: Infections ar old age (Alzheimer)
Problems in our skeleton and muscles
- Breaking bones
- Sprains
- Dislocations
- Strains
