9 science

Microbes

Any microscopic organism. Mainly bacteria, protists, some fungi, and even some tiny multi-cellular organisms.

Protists

Large group of organisms that have a very simple structure; the group include algae and unicellular organisms that live in water.

Bacteria

Unicellular organisms that have a very simple structure and no distinct nucleus.

Pathogens

Microbes that cause disease

Infectious diseases

Diseases that are spread by microbes and diffuse directly or indirectly from human to human.

Viruses

Tiny particles, smaller than bacteria and other pathogens, which must invade living cells in order to reproduce; when they invade, the cells are damaged or destroyed in the process releasing new particles to infect other cells.

Phagocytes

White blood cell that engulf and destroy invading microbes that cause disease

Phagocytosis

The process by which a cell engulfs foreign substances or other cells

Antibodies

Specialized proteins which are made from white blood cells that aid in destroying infectious microbes or the toxins they release.

Antibiotics

Drugs that block the growth and reproduction of bacteria.

Vaccination

A procedure that presents the immune system with a harmless variant of a pathogen, thereby stimulating the immune system to mount a long-term defense against the pathogen.

Fungi

any of a group of spore-producing organisms feeding on organic matter, including moulds, yeast, mushrooms, and toadstools.

Bacteria

They are microscopic living organisms that have only one cell. The word for just one is “bacterium.” Millions (if not billions) of different types of bacteria can be found all over the world, including in your body. They're on your skin and in your airways and mouth.

Virus

an infectious microbe consisting of a segment of nucleic acid (either DNA or RNA) surrounded by a protein coat. A virus cannot replicate alone; instead, it must infect cells and use components of the host cell to make copies of itself.

Nonspecific Defence - First line of defence

Physical Barrier:

• Skin

• Hair

• Sweat

• Tears

• Mucus

Nonspecific Defence - Second line of defence

Inflammatory Response:

• Increase Temperature

• Swelling of the infected areas

• Phagocytes

Specific Defence - Third line of defence

Immune Specific:

• Memory Cells

• Antibodies

Nervous System - Components

• Brain

• Spinal Cord

• Nerves

Nervous System - Route Impulses Take

• Sensory Receptors: collect information from inside and outside the body

• Effectors: Receive messages from Motor Neurons and move the body

Effects of spinal cord injury on breathing

• With a spinal cord injury of C4 and higher, all the muscles which control breathing will be paralysed. These are the intracostal muscles, the diaphragm and the abdominal muscles. In order to breathe, the person will need a machine called a ventilator to breath for them. In order to cough, the person will need help by way of a carer performing an assisted cough procedure.

• Injuries between C4 and T6 will leave the person able to breathe on their own. However, because the intracostal muscles may be weakened or paralysed depending on the level of injury, breathing may be done solely or mainly by the diaphragm. Again, coughing may also be a problem.

• Injuries between T6 and T12 do not normally affect breathing. However the ability to cough will be impaired.

• It is only with injuries below T12 that normal breathing and cough reflexes are preserved.

Parts of the brain - Cerebrum

Conscious brain

• controls thoughts

• Voluntary actions

• Language

Parts of the brain - Cerebellum

• controls coordination and learned muscular activity

• Located at the rear of the brain

Parts of the brain - brain stem

• controls essential ,‘subconscious’, actions (heart, blood vessels, breathing)

• Located at the base

Parts of the brain

• Cerebrum

• Cerebellum

• Brainstem

The Endocrine System

• A collection of glands in the body

• These glands send messages to other parts of the body through chemicals called hormones

Hormones

- Hormones are chemical substances that act as messengers in the body

- They are sent by endocrine glands

- Each hormone acts on a specific target organ/cell

Homeostasis

The process of maintaining a constant internal environment

Homeostasis - Constant factors

• Internal Temperature

• Blood solutes

• O2, CO2

• pH

• Urea and waste

• Concentration (balance of electrolytes vs water balance)

• Glucose

• Blood pressure and volume

Body systems in homeostasis - controllers

• Nervous System: Detects changes and initiates quick responses

• Endocrine System: Regulates bodily changes that are not required immediately. Often longer lasting

Body system in homeostasis - operatives ( effectors)

• Immune System: Defence, Repair and replacement of cells

• Circulatory System: Transports nutrients, wastes and hormones

• Digestive System: Breaks down and provides nutrients and H2O

• Respiratory System: Obtains O2 from and eliminates CO2

• Urinary System: Removes excess water, salt, acid, and urea

• Skeletal System: Storage reservoir for Ca2+.

Homeostasis - body temperature

• Humans need to maintain a body temperature of 37.5oC

• Enzymes (which speed up the chemical reactions vital for life) function best at 37.5 degree Celsius

• A change of only + or – 5 degrees could result in death

Kidneys

• Remove waste urea from the blood

• Remove excess salts and water from the blood to maintain water balance