PPP - homeostasis, body fluids, flow & pressure

Question 1

What is the purpose of short term homeostasis?

Answer 1

immediate survival

Question 2

What is the purpose of long term homeostasis?

Answer 2

health and reproductive capability

Question 3

What are some medium-term variables?

Answer 3

temperature, metabolic rate, appetite, GI secretions

Question 4

What is an example of a long term variable?

Answer 4

steroid hormone levels

Question 5

Give an example of hierarchy of importance for physiological variables?

Answer 5

Plasma osmolality will be maintained at the expense of blood volume by taking in more water - leading to hypertension

Question 6

What is the purpose of negative feedback?

Answer 6

to move a variable back to a set point when it is altered?

Question 7

When can the set point of a physiological variable be altered?

Answer 7

in fever or exercise

Question 8

What are the 3 types of negative feedback?

Answer 8

neuronal, endocrine and local/chemical

Question 9

Where are the integrating centres for negative feedback mechanisms?

Answer 9

in the midbrain and brainstem

Question 10

Give examples of peptide hormones?

Answer 10

ACH, oxytocin

Question 11

Example of a polypeptide hormone?

Answer 11

GH, insulin

Question 12

Example of a glycoprotein hormone?

Answer 12

LH, FSH, TSH

Question 13

Exampe of amino acid dervivative hormones?

Answer 13

adrenaline, T4

Question 14

Example of steroid hormones?

Answer 14

progesterone, androgens, glucocorticoids

Question 15

How do protein hormones work?

Answer 15

receptor binding on membrane induces 2nd messenger action

- effects are rapid and transient

Question 16

How do steroid/thyroid hormones work?

Answer 16

intracellular receptor binding alters gene transcription

- effects are slow and prolonged

Question 17

What is an example of local negative feedback?

Answer 17

local control of blood flow

control of blood volume

Question 18

What is feedforward control

Answer 18

anticipation of a change brings about a response before the change is detected

Question 19

What type of feedback is feedforward normally?

Answer 19

neuronal

Question 20

What are examples of feedforward control?

Answer 20

Pavlov’s reflex

fight or flight anticipation

Question 21

What is positive feedback, and what kind of control is it normally?

Answer 21

• when a change in varibale triggers amplication of that change
• usually hormonal

Question 22

What is an example of positive feedback?

Answer 22

parturition in labour increasing uterine contractions

Question 23

What 3 compartments is body water distributed into?

Answer 23

plasma (5%)
interstitial space (40%)
intracellular space (15%)

Question 24

How do you calculate interstitial space?

Answer 24

extracellular space - plasma volume

Question 25

How do you measure fluid compartments?

Answer 25

V = S/C | - add known amount of substance to unknown volume and measure the concentration

Question 26

What are the features of a substance for measuring fluid compartments?

Answer 26

- distributes to space of interest - non-toxic - not metabolised quickly

Question 27

What substances are used to measure plasma volume?

Answer 27

- don't cross capillaries easily | - albumin, inulin, evans blue

Question 28

What is used to measure extracellular space?

Answer 28

- substances that don't enter cells easily | - sucrose

Question 29

What is used to measure total body water?

Answer 29

- a substance that distributes with water | - 3H20

Question 30

What are the major constituents of fluids?

Answer 30

ions, proteins, dissolved gases, nutrients, metabolites, cells in blood

Question 31

Which ions determine osmolarity?

Answer 31

sodium, chloride and potassium

Question 32

What is the unit of osmolarity?

Answer 32

osmole

Question 33

What is the difference between osmolarity and osmolality?

Answer 33

``` osmolarity = 1 osmole/L osmolality = 1 osmole/Kg ```

Question 34

What is tonicity?

Answer 34

The osmolarity when solutions are seperated by a semi-permeable membrane

Question 35

What is crystalloid osmotic pressure?

Answer 35

pressure due to small diffusible ions

Question 36

What is oncotic pressure?

Answer 36

pressure due to proteins | - around 25mmHg

Question 37

What is the ionic composition of sodium?

Answer 37

plasma - 140mmol/L | intracellular - 10mmol/L

Question 38

What is the ionic composition of potassium?

Answer 38

plasma - 4mmol/L | intracellular - 120mmol/L

Question 39

What is the ionic composition of calcium?

Answer 39

plasma - 2mmol/L | intracellular - 100nmol/L

Question 40

Roughly what is the concentration of plasma proteins?

Answer 40

70g/L

Question 41

What are the main plasma proteins?

Answer 41

albumin alpha, beta and gamma globulins fibrinogen

Question 42

How much is haematocrit?

Answer 42

45%

Question 43

What is the concentration of erythrocytes?

Answer 43

4.8-5.5 x 10^12/L

Question 44

What is the concentration of leukocytes?

Answer 44

4-11 x10^9/L

Question 45

What are the types of leukocytes?

Answer 45

lymphocytes (20-40%) monocytes (2-8%) granulocytes

Question 46

What are the main types of granulocytes?

Answer 46

neutrophils, eosinophils, basophils

Question 47

What is the concentration of platelets?

Answer 47

150-400 x 10^9/L

Question 48

What happens to platelets when they are activated?

Answer 48

change shape, release granules and stick together