9. Homeostasis and Control Systems Flashcards Preview

PBCP- Introduction to physiology and blood > 9. Homeostasis and Control Systems > Flashcards

Flashcards in 9. Homeostasis and Control Systems Deck (20)
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1
Q

Define homeostasis

A

A situation in which active control minimise intra or extracellular change in the face of a changing external environment

2
Q

What are the different types of control?

A

Control of extracellular environment and control of intracellular environment

3
Q

What is negative feedback?

A

Any deviation of the controlled variable away from the normal value results in repsonses which reduce that deviation

4
Q

Why would negative feedback be deliberately introduced?

A

To inr

5
Q

Why would negative feedback be deliberately introduced?

A

To inrease the stability and accuracy of a system by correcting or reducing the influence of unwanted changes

6
Q

What are the three components of a homeostatic control system?

A

Detectors
Comparator
Effectors

7
Q

What does a negative feedback loop do?

A

One that tends to slow down a process

8
Q

What does a positive feedback loop do?

A

Tends to accelerate a process

9
Q

What are examples of feedback in biology?

A
Thermoregulation 
Insulin oscillations 
Operations of genes 
Repressor and activator proteins 
Hormones 
Enzymes
10
Q

What is the controlled variable for contractions and what happens?

A

Controlled variable- Oxytocine
Control at organ level (uterus)
Positive feedback loop continues until the baby is born

11
Q

What is the controlled variable for thermoregulation and what happens?

A

Core temperature
Control at whole body level
Stable overa large external temperature range

12
Q

What is the controlled variable for thermoregulation and what happens?

A

Core temperature
Control at whole body level
Stable over a large external temperature range

13
Q

What are the detectors for the thermoregulation?

A

Thermreceptors

Central and peripheral

14
Q

What is the afferent path for thermoregulation?

A

Sensory nerves

15
Q

What is the comparator for thermoregulation?

A

Hypothalmus

16
Q

What is the efferent path for thermoregulation?

A

efferent nerves

17
Q

How do effectors increase heat production ?

A

Increased skeletal muscle tone and shivering
Behavioural responses- relies on cognitive function and conscious activation of somatic nerves
Metabolic activity in brown fat

18
Q

How do effectors reduced heat loss?

A

Peripheral vasoconstriction
Piloerection in sympathetic nerves
Behavioural responses

19
Q

How is heat loss increased ?

A

Sweating through the sympathetic nerves
Peripheral vasodilation
Behavioural responses

20
Q

What is pyrexia?

A

Elevation of core temperature
Typically associated with infection
Results from abnormal “set point” in the hypothalmus