Unit 3. Interaction
INTERACTION FUNCTION
Humans interact with their environment using:
- The nervous system
- The skeleton and muscles
- The sense organs.
In this Unit we will divide the contents in two parts.
PART I.
The test will be next Friday 20th January.
NERVOUS SYSTEM
The nervous system is made up of star-shaped cells called neurons.
Neurons specialize in transmitting nerve impulses. They are connected to our receptor cells of the senses and to the effectors.
NEURON PARTS
- AXON: a long slender projection
- DENDRITES: various shorter projections
How nerve impulses are transmitted?
The neuron receives the nerve impulse and travels along the neuron to the end of it. The neuron transmits the nerve impulse to the next.
THE SENSES
SIGHT
The eyes are the organs of sight. Our eyes detect light around us and send messages to the brain that allow us to see.PARTS
- Eye ball: is a sphere that contains:
- A retina at the back with the receptor cells.
- Iris a colored area at the front with a hole in the middle called pupil. The pupil opens and closes depending on the amount of light.
- Lens are behind the iris and changes shape
- Auxiliary structures: protect the eyeball ad enable it to move. They include the eyebrows, eyelids, eye muscles and lacrimal glands.
How we see? Light enters the pupil through the lens to the retina. The receptor cells send signals through the optic nerve to the brain, which interprets the signals as colors, shapes and distances.
The ears are organs of hearing. Hearing is the sense that enables us to detect sound vibrations. PARTS:
- The outer ear: made up of:
- Pinna: the visible part of the ear.
- Ear canal
- The middle ear: made up of:
- Eardrum: is a membrane
- Chain of ossicles: which are 3 tiny bones: malleus, incus and stapes.
- The inner area made up of:
- Cochlea: contains the receptor cells.
- Three semicircular canals which contain the receptor cells sensitive to movement which help us to keep balance.
How we hear?
- Our ears detect sound vibrations, they enter the ear drum through the ear canal. The eardrum and the ossicles transmit the vibrations to the receptor cells in the cochlea.
- These cells send signals through the auditory nerve to the brain. The brain interprets the sounds that we hear.
- The olfactory bulb in the nose is the responsible for our sense of smell.
- Smell is the sense that enables us to detect substances in the air.
PARTS: - Olfactory bulb which contains the receptor cells
- Nostrils the two holes in the nose.
SMELL
The olfactory bulb in the nose is the responsible for our sense of smell.Smell is the sense that enables us to detect substances in the air.PARTS:
- Olfactory bulb which contains the receptor cells
- Nostrils the two holes in the nose.
How do we smell? The receptors in the olfactory bulb detect substances in the air and send this information to the brain. The brain interprets the information.
TASTE
The taste organ is made up of around 10.000 taste buds that are in the tongue.
How do we taste?The receptor cells in the taste buds detect substances that enter the mouth and send this information to the brain. The brain interprets the information generating the sensation of flavour.
We can detect 4 flavours: bitter, salty, sweet and sour
TOUCH
The organ which identifies touch is the skin. Our sense of touch allows us to identify touch, light and hard pressure, pain and temperature. The touch receptors in the skin can be found all over our body.
How do we touch? When the receptor cells in the skin detect a stimulis, they send thi
PART II.
THE NERVOUS SYSTEM
The nervous system transmits, interprets and responds to nerve impulses. It is divided in:
- The central nervous system: is made up of:
- The encephalon: that is divided in three parts:
- The brain: makes decisions and generated orders.
- The cerebellum: controls voluntary movements.
- The brainstem: controls automatic movements and links the encephalon to the spinal cord.
- The spinal cord: that goes from the encephalon to the lower part of the back. It transports the information between the receptors, the encephalon and the effectors. The spinal cord is connected to the nerves of the peripheral nervous system and it is protected by the spinal column.
- The encephalon: that is divided in three parts:
- The peripheral nervous system: is made up of the NERVES which link the receptors to the central nervous system.
THE SKELETON
The skeleton is a structure formed by bones and joints. Joints are the locations at which two or more bones connect to each other. The skeleton:
- Provides our body with a structural frame
- Protects our organs
- Serves as an attachments for muscles.
BONES
Bones are pieces of hard tissue that make up the skeleton. HEAD: SKUL, MANDIBLE TRUNK: SPINE, CLAVICLE, STERNUM, RIBS, SCAPULA ,PELVIS, COCCYX ARMS: HUMERUS, RADIUS, ULNA HANDS:CARPALS, METACARSALS AND PHALANGES LEGS: FEMUR, PATELLA, TIBIA AND FIBULA FEET: TARSALS, METATARSALS AND PHALANGES
https://www.liveworksheets.com/worksheets/en/Natural_Science/Bones/Bones_sy750171ujhttps://www.liveworksheets.com/worksheets/en/Science/Skeletal_System/Skeletal_system_to31046qi
JOINTS
Joints are the locations at which two or more bones connect to each other. There are 3 types of joints:
- SEMI-MOBILE JOINTS: have a limited movement such as ribs and the spine.
- IMMOVABLE JOINTS: hold bones such as the skull
- MOBILE JOINTS: these joints allow movement. Bones are connected to ligaments. Some examples are: elbow, knee..
MUSCLES
Muscles are formed by muscle cells, which become shorter when they receive a nerve signal. When the signal stops, they return to the original length. Muscles help us move.
TYPES OF MUSCLES:
- Muscles of the locomotor system that are attached to the skeleton by tendons. They contract when they receive a nerve signal.
- Other muscles such as the heart that are not attached to any bones.
MUSCLES
Head: temporalis.
Body: trapezius, pectorals, abdominals and gluteaus
Arms: triceps and biceps
Legs: quadriceps, adductor and calves.
