Basic Concepts in Physiology Flashcards
1
Q
what are excitable tissues?
A
- tissues composed of cells that are capable of producing action potentials
2
Q
definition of homeostasis
A
- a relatively stable condition of the internal environment that results from regulatory system actions
3
Q
the average adult male weighs how much
A
- 70 kg
- 154 lb
4
Q
total body water is
A
- 42 L
5
Q
water is what percent of body weight
A
- 55-60%
6
Q
total body water divided into what compartments?
A
- intracellular
- extracellular
7
Q
volume of intracellular compartment compared to extracellular compartment
A
- about 2x
8
Q
blood fills which compartment
A
- blood spans both intracellular and extracellular fluid
9
Q
plasma exchanges with
A
- interstitial fluid
10
Q
interstitial fluid exchanges with
A
- intracellular fluid
11
Q
osmolarity
A
- the total solute concentration of a solution regardless of the chemical composition of the solutes
12
Q
osmolarity is measured in
A
- osmoles/L
13
Q
1 osmole =
A
- 1 mole of solute
14
Q
1 osmole/L =
A
- 1 Osm
15
Q
Osmolarity of NaCl
A
- 2
16
Q
osmolarity of CaCL2
A
- 3
17
Q
the osmolarity of a human cell is
A
- 275-295
18
Q
less than 275 mOsm
A
- hypoosmotic
19
Q
275-295 mOsm
A
- isoosmotic
20
Q
more than 295 mOsm
A
- hyper osmotic
21
Q
how is osmotic concentration expressed clinically
A
- osmolality = osmoles/kg
22
Q
effective osmolarity =
A
- tonicity
23
Q
water concentration in regard to osmolarity
A
- higher osmolarity has lower water concentration
24
Q
water versus solute permeability in a cell
A
- water is permeable
- solutes are not
25
what happens in a hypertonic solution?
- cell shrinks
26
what happens in an isotonic solution?
- no change in cell volume
27
what happens in a hypotonic solution?
- cell swells
28
one of the most powerful features of the cell
- separation of charges across a semipermeable membrane
29
intracellular anions are mostly
- protein
30
extracellular anions are mostly
- Cl-
31
which cation is mostly prevalent inside the cell
- K+
32
which cation is mostly prevalent outside of the cell?
- Na+
33
concentration gradient of K+
- from inside of cell to outside
34
electrical gradient of K+
- develop inside negative membrane potential
35
result of negativity inside membrane
- begins to oppose further diffusion of K out of the cell
36
result of buildup of positive charge on outside of membrane
- begins to oppose further diffusion of K out of the cell
37
Nernst equation helps us determine
- equilibrium potential for a given ion
38
Nernst equation
- Ex=(60/z) * log(X out/X in)
x = is ion
z = charge of ion
X out = concentration of x in ECF
X in = concentration of X in cytoplasm
39
when does the Nernst equation apply
- when a membrane is permeable to only one ion
40
equilibrium potential for K+
-85.6 mV
41
equilibrium potential for Na+
+59 mV
42
equilibrium potential for Ca2+
+122 mV
43
equilibrium potential for Cl-
-82 -> -46 mV
44
biological membranes are permeable to
- not typically permeable to only one ion
45
2 major factors for determinants of membrane potential at any given time
- ion gradients
| - relative permeability of membrane to those ions
46
Goldman-Hodgkin-Katz equation applies to
- multiple ions and their permeabilities
47
resting Em Na+ and K+ channels
- some Na+ and some K+ channels are open
48
Em in resting Em
- is between E_Na and E_K
- closer to E_K
- generally -40 -> and -85 mV
49
which ion has greater permeability at rest
- permeability of K
50
where does Na move in regard to the cell
- moves into the cell
51
where does K move in regard to the cell
- moves out of the cell
52
what happens in ATP formation is impaired
- gradients decrease which changes Em
53
changes in Em are signals used by
- excitable cells
54
where does Ca2+ move in regard to the cell?
- moves into the cell
