Science Assessment Task 2

homeostasis, feedback loops, disease, pathogens, immune system, vaccines

homeostasis

the process by which the body maintains a constant, stable, balanced internal environment, despite changes in the external environment

conditions the body must keep stable in order to maintain homeostasis

temperature, blood glucose, pH (acidity), oxygen and carbon dioxide levels

ways your body cools you down

sweating, flushing (red face), vasodilation

ways your body warms you up

shivering, raising hairs (goosebumps), paleness of skin, vasoconstriction

what is shivering?

involuntary, small muscle contractions

how does sweating cool you down?

when sweat evaporates it removes heat from your body which cools you down

vasoconstriction

narrowing of blood vessels to reduce heat loss.

vasodilation

widening of blood vessels to increase heat loss

receptor

protein that detects a stimulus and performs an action in response

mechanoreceptor

detects pressure, touch and sound

thermoreceptor

detects changes in temperature

photoreceptor

detects light

chemoreceptor

detects chemical stimuli (molecules in air, food or blood)

examples of mechanoreceptors in body

skin and ear

examples of thermoreceptors in body

skin and central nervous system

examples of photoreceptor in body

retina of the eye

examples of chemoreceptors in body

nose, tongue and blood vessels

control centre

processes information and determines response

where does the control centre recieve information from?

the receptors

where does the control centre send the processed information to?

the effectors

effectors

organs/glands/muscles that work to reverse the change

response

the body will act and return to homeostasis

negative feedback loop

a feedback loop that does the opposite of what the original stimulus does

positive feedback loop

a feedback loop that amplifies what the original stimulus does

place in order: effector, response, stimulus, receptor, control centre

stimulus -> receptor -> control centre -> effectors -> response

thermoregulation

internal regulation of body temperature

what is the optimal temperature for humans to operate at?

37 degrees celcius

central nervous system (CNS)

a processing centre that manages everything your body does

name two body parts that are part of your CNS

brain and spinal cord

peripheral nervous system (PNS)

the nerves that connect the cns to the rest of your body

what does pns do

it sends info to different body parts and carries out commands from brain to various body parts

brain parts

cerebrum, cerebellum, brain stem

cerebrum

wrinkled tissue - most of the brain. responsible for many functions e.g. senses, personality, language, etc.

cerebellum

controls complex muscle movement

brain stem

connects cerebrum to spinal cord.

pathogen

a microorganism that causes disease by feeding off the host - causes infectious disease

disease

when body cannot function normally

living pathogens

bacteria, fungi, parasites, (protists)

non-living pathogens

viruses and prions

virus

microscopic, acellular (does not have a cell structure) and needs to live inside a host to survive (intracellular).

prion

misfolded protein particle that causes disease

bacteria

microorganism which is unicellular and lacks a nucleus (prokaryotic). Can multiply rapidly and cause disease.

fungi

organisms with a nucleus (eukaryotic) which feeds on other organisms.

salmonella (food poisoning) - infectious or non infectious, if applicable what pathogen?

infectious, bacteria

influenza - infectious or non infectious, if applicable what pathogen?

infectious, virus

cancer - infectious or non infectious, if applicable what pathogen?

non infectious

malaria - infectious or non infectious, if applicable what pathogen?

infectious, parasite

mad cow disease - infectious or non infectious, if applicable what pathogen?

infectious, prion

diabetes - infectious or non infectious, if applicable what pathogen?

non infectious

strep throat - infectious or non infectious, if applicable what pathogen?

infectious, bacteria

athletes foot - infectious or non infectious, if applicable what pathogen?

infectious, fungi

ringworm - infectious or non infectious, if applicable what pathogen?

infectious, fungi

lice - infectious or non infectious, if applicable what pathogen?

infectious, parasite

COVID-19 - infectious or non infectious, if applicable what pathogen?

infectious, virus

endemic

disease that is constantly present in a particular area or population

epidemic

a sudden increase in cases of disease above what is expected in a population or area

pandemic

when a disease spreads over multiple countries or continents and affects a large number of people

immune system

protects the body from pathogens

define 'innate'

born with

innate immune system

a barrier against pathogens, often is the first and second lines of defence

innate - specific or non-specific?

non-specific

adaptive immune system

a response to antigens by producing antibodies, often slower but more effective

adaptive - specific or non specific?

specific

phagocytes

a type of white blood cell capable of engulfing some types of pathogens

what is the process of a phagocyte engulfing a pathogen called?

phagocytosis

what are the scientific names of B and T cells

lymphocytes

which cell produces antibodies - B or T?

B

which cell identifies and kills pathogens - B or T?

T

how do T cells destroy pathogens?

by binding themselves to a pathogen and killing it

how do B cells destroy pathogens?

by turning into plasma cells and producing antibodies

how do B and T cells fight off disease faster?

by multiplying

what cells are created that remember how to fight of a disease?

memory cells

which immune system remembers how to fight off a disease?

adaptive immune system

first line of defence

line of defence that includes barriers that prevent pathogens from entering the body - non-specific

first line of defence barrier types

physical, chemical or biological

an example of each type of barrier

skin, saliva, stomach acid, good bacteria

second line of defence

If pathogen passes the first line of defense, the second line of defense starts - non-specific

what usually fights off invaders in the second line of defence?

phagocytes

what are some symptoms of the second line of defence?

inflammation - swelling, redness, heat, fever

how many days does it usually take to fight off an infection?

10-17 days

vaccination

the process of giving a vaccine to stimulate the immune system and provide protection against a specific disease.

how do vaccines work?

by inserting a dead or weakened pathogen to produce an immune response

antigen

the thing on the surface of a pathogen that triggers immune response

what disease discovered vaccines?

smallpox

what disease was a weaker version of another serious disease?

cow pox