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Flashcards in Homeostasis - ?? Deck (36):
1

Name the 11 body systems and what they do?

1. Integumentary - protects against external hazards and controls body temp.
2. Skeletal - Support and structure. stores minerals and make BC's
3. Muscular - movement, support and generate heat
4. Nervous - control centre
5. Endocrine - long term changes in other systems
6. Cardio - transports cells and materials in blood
7. Lymphatic - defends against infection
8. Respiratory - sound and delivers air
9. digestive - process food and nutrients
10. Urinary - eliminates excess water + pH
11. Reproductive - sex cells and hormones
embryonic development

2

Name the 4 ways homeostasis is maintained

1. receptor - detect changes
2. transmitter - sends info to control centre
3. control centre - receives info, then sends out commands
4. effector - responds to comman

3

What is negative feedback?

Effector engaged by the control centre, opposes the stimuli (e.g when temp increase/decrease)

4

What is positive feedback?

Effector engaged by control centre, exaggerates original stimuli (e.g. when BV breaks, chemicals keep being released to form clots)

5

List the electrolytic composition

ECF - mmol/L
Na = 137-145
K = 3.5-5.5
Cl = 100-109
Ca = 2.1-2.55
Mg = 0.7-1
ICF
Na = 10
K = 150
Cl = 10-20
Ca = 0.0001
Mg = 0.7-1

6

What 2 forms are NaCl found in? What has to be added to take the first form into account?

Non ionic (NaCl) or ionic (Na+ and Cl-)
Coefficient correction factor of 0.93

7

Where is the most water found?

ICF

8

How do we intake fluid?

Liquid/food
oxidation of carbs

9

How do we lose fluids?

Urination
Feces
Evaporation

10

What is the function of the kidney?

Receives CO, thus it removes toxins, regulates pH, electrolytes and water

11

How is water balanced in GI tract?

When ions are removed from GI, solute conc. decreases, thus water is absorbed to maintain osmotic equilibrium into IF

12

What happens if you can't excrete Na+

Oedema

13

What is renin?

protein released when renal perfusion decreased, thus increased BP -> Increased perfusion

14

What does poor renal perfusion lead to?

poor water and electrolyte absorption and excretion

15

What is aldosterone?

hormone which increases Na+ channels, thus increasing water uptake

16

What is ADH/Vasopressin?

hormone which increases aquaporins present, thus increases water uptake. This is released when electrolytes increased, or water increased in ECF

17

What is angiotensin 2?

increased BP

18

What is ANP and BNP?

when volume overload occurs, increases loss of Na and thus loss of water

19

What happens when sodium conc in ECF increases?

osmoreceptors in hypothalamus are stimulated.
This leads to increased ADH secretion (decreased aldosterone) thus you become thirsty and less water is lost
water from the ICF moves to ECF, thus Na conc. in ECF decreases, and homeostasis is restored

20

What happens when sodium conc in ECF decreases?

osmoreceptors in hypothalamus are stimulated.
decreased ADH and increased aldosterone, thus water loss increased, and not thirsty. ECF volume decreased, and increased osmolarity
increased Na+ conc. in ECF

21

How might ECF be gained?

increased water consumption or increased Na+ consumption

22

What happens when ECF volume increases?

increase BV and atrial distention
then release of natriuretic peptide
which leads to increase loss of Na (urine), increase water loss, decrease thirst and decreased ADH and aldosterone
Thus decreased blood volume and BP thus decrease ECF volume

23

What happens when ECF volume decreased?

decreased BP and BV
renin, aldosterone, angiotensin and ADH are activated
decreased water and Na loss, increase thirst and CO,
increased BV and BP -. increased ECF volume

24

What happens when you exercise?

You loose water AND Na

25

What does acclimatisation do to sweat?

0.4%-0.2% NaCl

26

What is hypo/hypernatremia?

Hypo: decreased Na+ conc.
Hyper: increased Na+ conc

27

What happens in dehydration?

loss of H20, so osmolarity increased (Na conc.) = blood is hypertonic.
When you drink pure H20, blood becomes hypotonic, so drink with salt
ALSO
decreased plasma volume, blood flow, SV and venous return
increased HR

28

What happens to K+ in cell

- charge influences K+ in the cell
increased K+ conc. in cell influences K+ out of cell

29

What happens to Na+ in cell

conc. gradient pushes Na+ in cell
As Na+ leaves ECF, Cl- in ECF makes it more charged, so favours Na+ out of cell

30

How does membrane potential come about?

ATPase pump pumps Na out of cell and K in - conc. gradient
K+ drives equilibirum to -90mV, whilst Na drives equilibirum to +60mV, but as K is more permeable, -70mv

31

What is Hyposmotic dehydration?

Loss of NaCl and loss of ECF volume
caused by diahrrea, vomiting, diuretics, kidney disease

32

What is Hyposmotic overhydration?

water retention => dilution of Na
caused by increased secretion of ADH

33

What is hyperosmotic dehydration?

loss of water
causes: decreased secretion of ADH, dehydration, kidney disease

34

What is hyperosmotic overhydration?

increased secretion of aldosterone

35

What is hyper/hypokalemia?

hyper: increased conc. of potassium
hypo: decreased conc. of potassium

36

What is hyper/hypocalcemia?

hyper: increased conc. of calcium
hypo: decreased conc. of calcium