MOD 8 - NON INFECTIOUS AND DISORDERS

Question 1

homeostasis

Answer 1

• process of maintaining stable internal environment despite changes in the external environment.
• can be done through mechanisms e.g. feedback loops

Question 2

tolerance range

Answer 2

narrow range of end points on external variables (pH, salt, sugar, temp) in which an organism can survive
- organism specific e.g human temp (0-35)

Question 3

set point

Answer 3

ideal value for variables in the tolerance range
- vary from individuals within a species
e.g. human temp

Question 4

negative feedback loop

Answer 4

decrease in the activity of the system upstream due to the production of something downstream

Question 5

positive feedback

Answer 5

increase in activity of a system upstream due to production of something downstream
- moves away from homeostasis

Question 6

KEY POSITIVE FEEDBACK MECHANISMS

Answer 6

1. child birth and oxytocin
2. cytokines in the immune system
3. blood clotting (precipitation of platelets)

Question 7

nervous system

Answer 7

• send messages following change in internal conditions to the brain
• brain sends responses from the brain to effect organs
• short intiation time
• shorter effect time

Question 8

2 main compartments of nervous system

Answer 8

1. central nervous system
2. peripheral nervous system

Question 9

central nervous system

Answer 9

brain, spinal chord and retina

Question 10

peripheral nervous system

Answer 10

peripheral nerves to all the organs

Question 11

endocrine system

Answer 11

• mediates release of hormones to enact responses to counteract change
• long term slower effects e.g. cytokines (maintain as long as hormone is in bloodstream)
• slower to respond to change

Question 12

organs of the endocrine system

Answer 12

• secretory glands that release horomones into bloodstream
  e.g. thyroid, adrenal glandsm hypothalamus, pituitary and pancreas

Question 13

hormone

Answer 13

chemical messengers made of proteins, carbohydrates and lipids

Question 14

3 main centres of nervous homeostasis

Answer 14

1. receptors - at site of change detects a deviation from homeostasis
2. sensory nerves - carry info to the brain which formulates response
3. response info carried by motor nerves to EFFECTOR ORGAN (if negative feedback loop -> counteract change

Question 15

spinal reflexes

Answer 15

• neutral connections between receptors and effector organs that don’t go to the central control centre (brain)
• quick action against dangerous stimuli
• info still goes to brain for secondary response
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