Homeostasis and Biological Rhythms Flashcards Preview

ESA 1 - Metabolism > Homeostasis and Biological Rhythms > Flashcards

Flashcards in Homeostasis and Biological Rhythms Deck (37)
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1

What is homeostasis? 

The maintenance of a stable internal environment 

2

What do homeostatic mechanisms act to do? 

Counteract the changes in the internal environment 

3

At what level does homeostasis occur? 

All levels - 

  • Cellular
  • Organ/system
  • Whole body

 

4

What factors does homeostasis control? 

  • Supply of nutrients
  • Supply of oxygen
  • Blood flow
  • Body temperature
  • Removal of waste
  • Control of CO2
  • pH

 

5

What does failure of homeostasis lead to? 

Disease

6

What are the components of the control systems in the body? 

  1. Communication
  2. Control centre
  3. Receptor
  4. Effector

 

7

What are the main communication pathways in the body? 

  • Nervous system
  • Endocrine system 

 

8

What does the nervous system use? 

Hormones 

9

What is paracrine control? 

Local release (via ducts/exocrine) and action 

10

What is autocrine control? 

When agents are released by a cell which affects the releasing cell 

11

What can the peripheral nervous system be divided into? 

The afferent branch (sensory input) and the efferent branch (motor output) 

12

What does the control centre do? 

  • Establishes the reference set point
  • Analyses the afferent input
  • Dtermines the appropriate response

 

13

Give two important control centres in the brain

  • Diencephalon 
  • Medulla oblongata

 

14

Where is the dicephalon located? 

In the hypothalamus 

15

Where is the medulla oblongata located? 

In the brain stem 

16

What is the hypothalamus involved in the regulation of? 

The endocrine system 

17

What are regions of the medulla involved in the control of? 

  • Ventilation
  • Cardiovascular system 

 

18

What are receptors required for in the bodies control systems? 

Detect stimuli such as changes in the internal environment

19

Give two examples of receptors

  • Chemoreceptors
  • Thermoreceptors

 

20

What are receptors usually made of? 

Specialised nerve endings 

21

How do sensors communicate input to the control centre? 

Via the afferent nerves 

22

What do effectors do? 

Cause change 

23

What happens to the output produced by the control centre? 

It is communicated via efferent pathways to the effectors 

24

Give an example of an effector? 

Sweat glands, which can be activated to produce more sweat, causing heat loss

 

 

25

Give an example of a control system in the body

The hypothalamic-pituitary-adrenal axis 

26

What is it called when the set point for homeostasis varies over time? 

Biological rhythm 

27

Give an example of a level varies during the day

Level of the hormone cortisol 

28

When does cortisol levels reach their peak? 

Around 7am 

29

When are cortisol levels at their lowest? 

About 7pm 

30

What is it known as when levels vary over roughly a 24 hour cycle? 

Circadian rhythm