The Nervous System
1. The Central Nervous System consists of the Brain and the Spinal Cord.
2. The Cerebral hemispheres connect senses such as hearing and seeing to the muscles for movement.
3.The cerebellum controls automatic responses such as breathing and the heartbeat.
4.The skull protects the Brain and the Backbone protects the Spinal Cord.
The Different Parts of The Skin
- Sweat Glands: Produce sweat that can be evaporated eventually leaving the body cool.
- Nerve Ending: Allow the sking to feel pain, temperature and pressure.
- Oil Glands: Produce oil on the skin, leaving the sking soft and waterproof.
- Blood Capillaries: Carries blood and regulates temperature.
- Effector Muscles: The hairs on the skin rise trapping air next to the skin, leaving the body warm.
- Epidermis: The outer layer of the skin
Responsing To a Stimulus
1. Stimulus: A change in the environment.
2. Receptor: Specialised cells that detect changes in the environment. E.g: the sense organs are receptors, the eye detects light.
3. Effector: Part of the body that produces a response. E.g: muscles contracting to pull the hand away from a hot pan.
1. Involuntary Response: Are responses that happen without you thinking, they are automatice. As they are automatic they bypass the brain and do not require any thinking.
- Blinking when dust gets in you eye
- Ducking down when a ball is thrown at you
2. Voluntary Response: Are responses that need to be decided an dthought through, in this case they do require the brain as a thought process.
- Walking down the street
- Talking to your friend
- Cerebrum: Thinking, memory and speech.
- Temporal Lobe: Language and speech.
- Frontal Lobe: Emotion, mood and personality.
- Parietal Lobe: Sense organs such as see, touch, taste etc...
- Occipital Lobe: Vision.
- Cerebellum: Movement.
- Pituitary Gland: Secrets hormones.
1. Pain is actually created by the Brain after the reflex action has been completed.
2. Reflexes action are very quick and involuntary (which means they happen automatically). They happen very fast which means they are especially useful when in dangerous situations, where the body needs to be protected. The 3 main neurones that are involved in reflexes actions are:
'Sensory neurone ' 'Relay Neurone ' and 'Motor Neurone '
A 'synapse' is the junction or gap between two neurones.
When an impulse is sent from one neurone to another, in the synapses a chemical substance is secreted out of the neurone on it's way to the other neurone. This chemical substance is called 'Neurotransmitters'.
There are 3 main neurones in the brain and they are:
- Sensory Neurone: Carries signals from the sense organ (receptor) to the Central Nervous System (CNS).
- Relay Neurone: Carries messages to one part of the CNS to the other. E.g: The spinal cord to the brain, vice versa
- Motor Neurone: Carries signals from the CNS to the effector.
- The CNS: The brain and the spinal cord.
- Synapse: A junction between 2 neurones.
- Electrical Impulses: How signals within a nerve cells.
- Neurones: Are nerve cells that carry information as tiny electrical signals.
- Neurotransmitter: Chemical substances that pass through the synapses.
- Axon: Is the long part of the neurone that carries the signal.
- The ciliary muscles and Suspensory Ligaments: Change the shape of the lens.
- The Iris: Controls the amount of light that enters the eye.
- The Lens: Focuses images onto the sensitive part of the retina.
- The Pupil: Lets light into the eyes.
- The Corena: Focuses images onto the back on the eye.
- The Retina: Layers of rod and cone cells.
- Rod Cells: Detect black and white images in the dark.
- Cone Cells: Detect coloured images in the light.
Accommodation and The Iris Reflex
is when the eye is able to focus images distant and near by.
- Distant Image: Thin lens
- Nearby: Thick
The Iris Reflex:
- In bright the pupil size decreases, this is because the radial muscles relax and the circular muscles contract. this stops the damaging of the retina.
- In dim light the pupil size increases, this is because the radial muscles contact and the circular muscles relaxes. This makes our night vision better.
Why Are They There???
Eyelashes: Don't allow dust to enter the eyes.
Eyebrows:To show emotion and facial expressions.
Dilate: To get bigger.
Constrict: To get smaller.
Iris Reflex: Controlled by the Central Nervous System (CNS)
Retina:Detector of light acts as a receptor.
Iris:Provides a response acts as a effector.
Compostition of Blood
The Red Blood Cells:
- Carry oxygen from the lungs to other parts of the body. It contains a red pigment called 'Haemoglobin' which gives blood it's red colour.
- Are tiny fragments of cells that help clot blood when the skin is cut open.
White Blood Cells:
- Are part of our Immune System, which help fight diseases in the body.
- The liquid part of the blood. It's yellowy in colour and mostly made up of water and dissolved substances.
is a chemical messenger called a hormone.
- It is produces by the 'Adernal Glands', which are located above the kidney.
- Prepares the body for action
How Adrenaline affects the body??
- Your breathing becomes faster, this is because the bronchioles in the lungs widen allowing more air into the lungs.
- Heart beats faster, this is also because the tubes in the body getting wider letting in more oxygen to be carried in the blood.
- Your skin becomes pale, this is because the blood underneath the surface of your skin, has diverted to other core essential orangs. E.g: Heat and Lungs.
Quick Notes About Adrenaline
The Menstrual Cycle
More About The Menstrual Cycle
- Made in the pituitary gland (in the brain)
- Matures and develops the growth of the egg
- Stimulates the production of oestrogen
- Made in the ovaries
- Stimulates the production of LH
- Inhibits the production of FSH, so only one egg can be matured
- Made in the ovaries
- Maintains the lining of the uterus and stops it from breaking down
How does contraception work?
- High doses of oestrogen and progesterone prevent the fertilised egg implanting in the womb.
- When a man and woman have sexual intercourse, and the woman does not want to become pregnant she can take the 'morning after pill' (which is the contraception pill).
- Even it's called the morning after pill, it take about 3 to 4 days until it takes full effect.
The Negative Feedback Loop
The Negative Feedback Loop:
Oestrogen made in ovaries
LH made in the pituitary gland
Progesterone made in the Corpus Luthem
FSH made in the pituitary gland
Use Misuse and Abuse
Pathogen: A micro-organisms that causes infectious diseases.
- Viruses are a type of microbes
- Tiny organisms called germs
- Also known as micro-organisms
- Air borne: diseases spread through droplets in the air
- Direct contact: touching an infected person
- Indirect contact: using or sharing an object an infected has used
- Vector borne: an animal or insects is carry the microbe
Vertical and Horizontal Infections:
1. Vertical: Is when a pregnant woman can pass on her diseases to the unborn child through the placenta.
2. Comin in contact with an infected person, by swap bodyliy fluids
E.g: Sexual intercourse, kissing etc...
Keeping Microbes Out
First Line of Defence:
- Ear Wax
- White Blood Cells
- Watery Eye (Lysozyme)
- Hydrochloric acid in the stomach
3 ways of defending the body:
1. Physical and chemical barriers
2. Non-specific Immunity: White Blood Cell + Inflammation
3. Specific Immunity: Specialised White Blood Cell + The Immune System
Second Line of Defence