The document discusses sensitivity and coordination in the human body. It covers the nervous system, senses, voluntary and involuntary movements, and the skeletal and muscular systems. The nervous system receives internal and external stimuli through receptors and responds through muscular or glandular responses. It summarizes the key parts and functions of the senses of sight, smell, hearing, touch, and taste. It also outlines the main components of the central and peripheral nervous systems and neurons.

1. SENSITIVITY AND COORDINATION
BY MARCOS SÁNCHEZ
Marcos Sánchez Herrero. 6ºB

2. STIMULUS AND RESPONSE
 Stimuli
A stimulus is anything you see, hear, touch, smell or taste.
Stimuli can be internal or external:
 Internal stimuli come from inside our bodies. External stimuli come from outside the body.
The body has different receptors to recive different types of stimuli.
 Internal receptors recive the internal stimuli our bodies produces
 External receptors recive external stimuli. They are in the sensory organs: the eyes, the nose, the
tongue, the ears and the skin.
 Responses
o A response is the body´s answer to a stimulus.
o There are two types of responses: - Muscular responses.
- Glandular responses.

3. THE SENSES
 Sight:
The eye is the organ of sight, It is made up of the eyeball and protected by the eyebrows, eyelids and eyelashes.
1º.- First light goes through the cornea.
2º.- Then ligh passes through the pupil, the opening of
the iris.
3º.- After that light passes through the lens which
focuses the image on the retina.
4º.- Finally the information in the retina travels to the
brain through the optic nerve.
 Smell
The nose is the organ of smell. The receptors of smell are in the pituitary gland, inside the nostrils.
Pituitary
Nostrils

4.  Hearing
The ear is the organ of hearing.
1º.- The outer ear receives sounds.
2º.- The middle ear changes sounds into vibrations.
3º.- The inner ear changes vibrations into nerve
impulses that go to the brain
 Touch
The skin is the organ of touch. It is made up of three layers.
Epidermis
Dermis
Hypodermis
 Taste
The tongue is the organ of taste.
The receptors of taste are in the taste buds. Taste buds
There are taste buds all around the tongue.

5. WHAT IS THE NERVOUS SYSTEM?
 The nervous system
The nervous system is made up of nerve centres and
nerves.
- The central nervous system has two parts:
- * The brain is inside the skull. Il is made up of
the cerebrum, the cerebellum and the brain
stem.
- * The spinal cord is made up of many neurons. It
is protected by vertabrae.
- - The peripheral nervous sistem is made up of:
- * Sensory nerves.
- * Motor nerves.
 Neurons
Both the central and peripheral nervous systems are
made up of specialised cells called neurons.
They are made up of a: -cell body.
-dentrites.
-axons.

6. VOLUNTARY AND INVOLUNTARY MOVEMENTS
 Voluntary movements:
The brain produces a response in the case of voluntary movements.
 Involuntary movements:
The spinal cord produces a response in the case of involuntary movements.

7. THE SKELETAL AND MUSCULAR SYSTEM
The skeleton Joints
The joints are located where two or more
bones meet.
There are three types of joints:
• Moveable joints.
• Semi-moveable joints.
• Fixed joints.
skull bones
lower limb bones

8. The musculature
Head muscles
Trunk muscles
Limb muscles
Tendons
Tendons are made up of flexible and fibrous tissues.