Week 13

Question 1

Homeostasis

Answer 1

regulating the internal environment in the face of a challenging outside environment

Question 2

What is the most common type of feedback to achieve homeostasis?

Answer 2

Negative feedback

Question 3

What percentage of intracellular fluid is water?

Answer 3

40%

Question 4

What percentage of extracellular fluid is water?

Answer 4

20%

Question 5

Bioelectricity

Answer 5

The flow of a particular ion carrying charge

Question 6

Out of ECF and ICF, which has the higher Na+ conc?

Answer 6

ECF has a higher Na+ conc

Question 7

Equation showing how resistance affects air flow into lungs?

Answer 7

Flow= P2-P1/Resistance

Question 8

What impact does fibrosis have on the lungs?

Answer 8

Scarring and thickening of the alveoli membranes

Question 9

What does solute conc do during osmosis?

Answer 9

Low solute to high solute conc

Question 10

What sets the volume of each fluid compartment?

Answer 10

The ionic balance

Question 11

Should ICF:ECF be isotonic, hypertonic, or hypotonic?

Answer 11

isotonic

Question 12

What is ECF volume determined by?

Answer 12

Na+ conc which is regulated by the kidneys

Question 13

Van Hoff’s Law

Answer 13

iRTC

Question 14

Boyle’s Law

Answer 14

P1V1=P2V2

Question 15

Aquaporin

Answer 15

How water moves through the lipid bilayer

Question 16

What does cell excitability allow to happen?

Answer 16

Bioelectricity lets effectors respond to stimuli

Question 17

What does increased open probability mean?

Answer 17

Increased flow/conductance

Question 18

Electrophysiology

Answer 18

Measurement of ion channel activity

Question 19

Membrane potential

Answer 19

Ions have moved up until this point where an equilibrium is reached and it’s no longer favourable for ions to move. Electrical difference stops flow even if there is still ion conc difference.

Question 20

Which ion is the main determinent of resting membrane potential?

Answer 20

K+

Question 21

Is acetylcholine receptor ligand gated or voltage gated?

Answer 21

ligand gated

Question 22

Is NMDA (glutamate receptor) ligand gated or voltage gated?

Answer 22

ligand gated

Question 23

Are Na+ and K+ ligand gated or voltage gated?

Answer 23

voltage gated

Question 24

Deactivation

Answer 24

closed but capable of opening

Question 25

Inactivated

Answer 25

closed fully

Question 26

Where is the action potential initiated in a nerve?

Answer 26

Usually the axon hillock

Question 27

What's the maximum frequency of an action potential?

Answer 27

1kHz

Question 28

Why do cardiac myocytes take longer to repolarise than the average neurone?

Answer 28

To let tension build up in the muscle cell so full force is used

Question 29

Fibrillation

Answer 29

Fluttering of the ventricles so blood isn't pumped properly

Question 30

How is a muscle action potential initiated?

Answer 30

Ach activates ligand gated receptor, allowing flow of ions, generating an end plate potential

Question 31

Give an example of a negative feedback loop

Answer 31

Blood pressure, body temperature

Question 32

Give an example of a positive feedback loop

Answer 32

Childbirth, action potentials, blood clotting

Question 33

What percentage of water in the body is intracellular fluid vs extracellular fluid?

Answer 33

Intracellular= 40% Extracellular=20%

Question 34

What is another word for extracellular fluid?

Answer 34

Interstitial fluid

Question 35

What makes up interstitial fluid?

Answer 35

Blood plasma and tissue fluid

Question 36

What is the concentration gradient like for Na+ from ECF to ICF?

Answer 36

ECF= hi Na+ ICF= lower Na+

Question 37

What is Boyle's Law about?

Answer 37

Chest expansion reduces pressure in the lungs causing air to flood into the lungs.

Question 38

What does the flow of air into the lungs depend on?

Answer 38

Pressure difference and resistance

Question 39

What are some examples that could increase resistance to air flow into the lungs?

Answer 39

Asthma Infection

Question 40

Boyle's Law: Flow=

Answer 40

Flow= (P1-P2)/ Resistance

Question 41

What is Fick's Law about?

Answer 41

Diffusion (alveoli are specialised for maximum diffusion)

Question 42

What is the impact of fibrosis on the lungs?

Answer 42

Thickening/ scarring of membranes so reduced flow

Question 43

What happens to solute levels and osmotic pressure during osmosis?

Answer 43

Lo Solute+ Lo osmotic pressure turns into... More solute+ Hi osmotic pressure

Question 44

How is the volume of each compartment set by the ionic balance of ECF and ICF?

Answer 44

ICF+ECF should be isotonic therefore the strength of ions or molecules should be the same, so the volume of the fluid compartment is set

Question 45

Name the three states of tonicity?

Answer 45

Isotonic Hypertonic Hypotonic

Question 46

What is Van Hoff's law about?

Answer 46

osmotic pressure

Question 47

Van Hoff's Law Change in osmotic pressure=

Answer 47

Change in osmotic pressure= iRTC(Cx-Cy)

Question 48

What does the Nernst equation calculate?

Answer 48

Cell potential

Question 49

What conditions and for which ions is the Nernst equation suitable?

Answer 49

Physiological conditions Monovalent +ve ions

Question 50

What does the Goldman (GHK) equation predict?

Answer 50

Predicts membrane potential

Question 51

What is the human brains primary excitatory NT?

Answer 51

Glutamate

Question 52

Define electrogenic

Answer 52

relating to the production of electrical activity in a living tissue

Question 53

What ion mainly causes depolarisation of the cell membrane?

Answer 53

Na+

Question 54

What are the three stages of action potential? and what order do they go in?

Answer 54

1. Deactivation (resting) 2. Activated (Depolarisation) 2. Inactivation (Repolarisation)

Question 55

During the deactivation stage, what is the ion channel doing?

Answer 55

It's closed but capable of opening (door is shut but not locked)

Question 56

During the activation stage, what is the ion channel doing?

Answer 56

Ion channel is open so Na+ rushes in, rapidly going from threshold to peak

Question 57

During the inactivation stage, what is the ion channel doing?

Answer 57

Plugged ion channel. Membrane is More slowly returning to resting potential

Question 58

What ion copies the action potential when plotted as a graph?

Answer 58

Na+

Question 59

Where does K+ peak if plotted on an action potential graph?

Answer 59

Smaller and after the action potential peak

Question 60

In a neuron cell where would the action potential be initiated?

Answer 60

Axon hillock

Question 61

Define refractory period

Answer 61

Time taken for inactivation to wear off, a pause before the next action potential

Question 62

What is the maximum frequency of ac action potential?

Answer 62

1kHz

Question 63

What kinds of nerve cells may not be myelinated?

Answer 63

small pain fibres

Question 64

What speeds up an action potential?

Answer 64

Myelintion

Question 65

What slows down an action potential?

Answer 65

Bigger nodes of ranvier (more leaky)

Question 66

What is the cardiac myocytes special talent?

Answer 66

Takes longer to repolarise than the average neurone

Question 67

Why does a cardiac myocyte take longer to repolarise?

Answer 67

So tension can build up so the full force of the muscle cell is used

Question 68

How is tension achieved by cardiac myocytes?

Answer 68

Calcium lets tension build up as it's triggered by rising membrane potential

Question 69

How is the image of an ECG created?

Answer 69

Add up all the action potentials in the heart muscle

Question 70

What Neurotransmitter is used at the NMJ?

Answer 70

acetylcholine