Disease science Y9

Homeostasis

maintenance of a stable internal environment within tolerance limits

Why must internal body temperature be maintained at 37°C?

To allow cellular chemical reactions, like respiration, to occur at their optimum rate.

How does the body maintain a stable internal pH?

Through the continuous excretion of carbon dioxide (CO₂).

What are the components of the negative feedback loop for thermoregulation?

Stimulus, receptor, control centre, effector, and response.

What are the human effectors for cooling down when hot?

Sweating and vasodilation (blood vessels widening near the skin).

What are the human effectors for warming up when cold?

Shivering and vasoconstriction (blood vessels narrowing near the skin).

How does the pancreas lower blood glucose after a meal?

By secreting the hormone insulin.

How does the pancreas increase blood glucose during fasting?

By secreting the hormone glucagon.

What are the main components of the Central Nervous System (CNS)?

The brain and the spinal cord.

What are the main components of the Peripheral Nervous System (PNS)?

Peripheral nerves, including sensory and motor neurons.

What are the key structural parts of a neuron?

Dendrites, cell body, nucleus, axon, myelin sheath, and synapse.

What is the nature of signals sent by the nervous system?

Rapid, short-lasting electrochemical impulse

How does the nervous system respond rapidly to pain?

Via a reflex arc, bypassing the brain for an immediate response.

What are three major hormone-producing glands in the body?

The pituitary gland, thyroid gland, and pancreas.

How does the endocrine system transmit signals?

releasing chemical hormones into the bloodstream.

How do endocrine signals compare to nervous signals?

They take longer to travel via the bloodstream, but has long lasting effects, whereas nervous signals last short-term but are quicker, electrochemical impulses

Infectious Disease

A disease caused by an invading pathogen.

How are pathogens broadly classified?

As either cellular (living) or non-cellular (non-living).

What are the key features of a virus?

Non-cellular, contains genetic material, and has no cellular membrane.

What are the key features of bacteria?

Unicellular, possesses a cell membrane, but lacks a nucleus.

What are the key features of fungi?

Unicellular or multicellular, possessing both a cell membrane and a nucleus.

What are macro-parasites?

Multicellular, cellular pathogens visible to the naked eye.

Epidemic

The rapid spread of infectious disease to many people in a population quickly.

What does the SIR model stand for in disease tracking?

Susceptible, Infectious, and Recovered.

What constitutes the body's first line of defence?

Physical and chemical barriers like skin, stomach acid, and mucous membranes.

What is the role of foreign (non-self) antigens?

To trigger an immune response by being recognized as foreign.

What constitutes the body's second line of defence?

Non-specific localized responses, including inflammation, fever, and phagocytosis.

What constitutes the body's third line of defence?

A specific, whole-body response involving specialized white blood cells (lymphocytes).

How do memory cells provide immunity?

They recognize specific antigens to launch a rapid response upon re-exposure

How does secondary exposure compare to primary exposure on an antibody graph?

Secondary exposure shows a much faster and significantly higher peak in antibody concentration.

Vaccine

A weakened or inactivated pathogen/antigen introduced to stimulate immune memory.

Why are vaccine booster shots sometimes necessary?

To maintain or restore protective antibody concentrations over time.

Herd Immunity

Disease protection in a population when a high percentage of individuals are vaccinated.

What are the three categories of non-infectious diseases?

Genetic, environmental, and nutritional.

Match non-infectious categories: Genetic, Environmental, Nutritional to examples.

Genetic: Sickle cell; Environmental: Melanoma; Nutritional: Scurvy.

What is the primary cause of melanoma?

Exposure to ultraviolet (UV) radiation from the sun.

Incidence of Disease

The number of new cases of a disease in a specific time period.

What are four strategies to reduce non-infectious disease incidence?

Educational campaigns, genetic screening, legislation, and pre-emptive screening.

What are three key measures used to reduce COVID-19 spread?

Quarantine, hygiene practices, and personal protective equipment (PPE).

Why is recognizing Indigenous plant knowledge beneficial for science?

It provides valuable leads for modern pharmacology and sustainable disease treatments.

Phagocytosis

When a specialised cell- phagocytes- engulfs particles like bacteria and viruses from the body.