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Flashcards in Physiology Deck (52)
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1

What are the components of a phospholipid?

Hydrophobic tail + hydrophilic head

2

Bonds between phospholipids are strong. True/False?

False
Bonds are weak - explains the fluid nature of the membrane

3

Cholesterol contributes to which two aspects of the membrane?

Fluidity and stability

4

What are the 3 main types of proteins found on the membrane?

Integral (receptors)
Transmembrane (channels, transporters)
Peripheral (enzymes)

5

The glycocalyx layer is formed by...

Short carbohydrate chains bound to proteins and lipids

6

What are desmosomes?

Adhering junctions that anchor cells together

7

What are tight junctions?

Join lateral edges of epithelial cells near their apical membranes

8

What are gap junctions?

Communicating junctions that allow movement of charge between adjacent cells

9

2 main factors that influence whether a particle can passively permeate the membrane

Lipid solubility (non-polar pass easily)
Size

10

Diffusion is movement from ___ to ___ concn

High to low

11

Fick's law of diffusion describes the rate of net diffusion and is made up of...

Magnitude of concn gradient
SA available for diffusion
Lipid solubility and size/weight of substance
Distance over which diffusion must occur

12

Osmolarity is defined as...

The number of osmotically active particles present in a solution

13

How is osmolarity calculated?

Using molar concn (mM) and number of osmotically active particles (n)

14

150mM NaCl has osmolarity = ?

150 x 2 (Na+ and Cl-) = 300mOsm

15

A hypotonic solution will ____ in cell volume

Increase (needs mOre water)

16

Facilitated diffusion requires energy. True/False?

False

17

Active transport transfers a substance from high to low concn. True/False?

False
Low to high

18

_ Na+ out for every _ K+ in with regards to Na-K pump

3, 2

19

Secondary active transport occurs by which 2 mechanisms? Define them

Symport (co-transport): solute and ion move in same direction
Antiport: solute and ion move in opposite directions

20

Membrane potential (Em) arises due to...

Separation of opposite charges across the membrane

21

At resting potential, the membrane is 100x more permeable to sodium than potassium. True/False?

False
100x more permeable to K+ than Na+

22

Em for K+ is approx...

-90mV

23

Em for Na+ is approx...

+60mV

24

Nernst equation

Eion = 61log[ion]o / [ion]i

25

Membrane potential is much closer to the potential of Na+ ions. True/False?

False
Much closer to Ek+ due to greater permeablity of K+

26

Em for a typical nerve cell at rest = ?

-70mV

27

GHK equation (used to calculate membrane resting potential)

Em = 61log x PK+[K+]o + PNa+[Na+]o / PK+[K+]i + PNa+[Na+]i

28

Which receptors control mean arterial BP? Where are the receptors, control centre + effectors located?

Baroreceptors, located in aortic arch + carotid sinus
Control centre: medulla oblongata
Effectors: heart + blood vessels

29

Normal range for MAP?

70-105 mmHg

30

Formulae for calculating MAP?

MAP = [(2x diastolic) + systolic]/3
MAP = diastolic + [systolic - diastolic]/3
MAP = CO x TPR