Homeostasis Flashcards Preview

Biology - Unit 1 > Homeostasis > Flashcards

Flashcards in Homeostasis Deck (15):
1

What is meant by negative feedback?

Bringing back monitored variables within a set range

2

What is the overall goal of homeostasis?

To allow maintenance of an optimum internal environment

3

What is defined as feed forward systems?

When the body anticipates and responds to changes in the environment before they have an effect.

4

Give two examples of feed forward mechanisms?

Salivating before eating
Skin activates response to temperature before internal body temperature change arises

5

What is positive feedback?

An initial disturbance sets off a train of events that leads to an even greater disturbance.

eg - action potential

6

How does daily input and output of water compare on a daily basis?

It is the same

7

What fraction of body water is ICF?

Two thirds

8

How much of ECF is plasma?

20%

9

Why do women and old people have lower water content?

Women have a higher proportion of body fat
Old people have less muscle

10

What is the only difference in composition between ISF and plasma?

Plasma contains plasma proteins

11

Concentration =

Mass/volume

12

What is the only region who's water content can be directly measured?

Plasms

13

Give examples of substances that can be used to measure the ECF?

Sucrose
Na+
Cl-

(Substances that can not pass over the plasma membrane)

14

What is used to measure the water content of the plasma?

Radioactively labelled or dyed proteins

15

How do you measure total body water?

Using a radioactive water (deuterium oxide)