WK - Cell Physiology And Mechanotransduction In Exericse, Adaptation And Injury

Question 1

Define passive transport

Answer 1

The movement of molecules across the cell membrane down a concentration gradient without the need of energy, using kinetic energy and natural entropy of molecules

Question 2

Define active transport

Answer 2

The movement of molecules across a cell membrane from a region of lower concentration to a region of higher concentration

Question 3

What are the similarities between active and passive transport

Answer 3

They both move with concentration gradient

Question 4

What is a cell

Answer 4

The smallest unit that can live on its own and makes up all living organisms and tissues of the body

Question 5

Considerations for the type of transport

Answer 5

1- substance permeability
2- rate

Question 6

What are the structural components of the cell membrane in passive and active transport

Answer 6

• phospholipid bilayer
• channel protein
• carrier proteins

Question 7

Describe the phospholipid bilayer

Question 8

Describe channel proteins

Question 9

Describe carrier proteins

Question 10

What are the transport mechanisms

Answer 10

• passive diffusion
• facilitated diffusion
• active transport

Question 11

Define passive diffusion

Question 12

Define facilitated diffusion

Question 13

Define active transport

Question 14

What factors determine the rate that these transport mechanisms occur

Answer 14

• substance permeability
• rate

Question 15

What is the action and role of ion pumps

Answer 15

• they are membrane proteins that use energy (ATP) to move ions via active transport
• ions carry charge
• ion pump action results in an electrochemical gradient between the cell exterior and interior which creates a voltage across the cell membrane, enabling nerve impulses and muscle contractions

Question 16

What is the role and action of the sodium potassium pump

Answer 16

1- makes the [Na+] high in the extracellular space and low in the intracellular space
2-makes the [K+] high in the intracellular space and low in the extracellular space
3- it gives the intracellular space a negative voltage at rest with respect to the extracellular

Question 17

Describe membrane potential/transmembrane potential

Answer 17

There is a resting difference in electric potential between the inferior and exterior of a cell

Question 18

Define depolarisation

Question 19

Define action potentials

Question 20

How does transmembrane tie in with depolarisation and action potentials

Question 21

Define mechanotransduction

Answer 21

It is the process whereby mechanical stimuli (forces) are converted (signal) into biological responses (protein regulation to change tissue) within your cells

Question 22

How does mechanotransduction fit in with physio

Answer 22

• for the stimulation of tissue repair and remodelling
• a major method to optimise patient outcome
• making clinical decisions to precisely manipulate load and loading parameters to drive the tissue changes and adaptations that we are seeking, with the basis of the PST

Question 23

What are the 3 stages of mechanotransduction

Answer 23

These all occur through cell signalling/communication between each phase
1) mechanocoupling
2) cell-cell communication
3) effector response

Question 24

Describe stage one (mechanocoupling) of mechanotransduction

Answer 24

• mechanical trigger or catalyst
• a load causes a physical perturbation to tissue
• the forces mechanically stress and deform the cells that make up the tissue
• this results in a response within and between cells where the nature of the response is determined by how the load is applied (load parameters)

Question 25

Describe stage two (cell-cell communication) of mechanotransduction

Answer 25

- communication throughout tissue to distribute the load message - tissue contains countless cells within an ECM - neighbouring cells communicate info about the load/mechanical stimulus encounter by the tissue - intercellular communication occurs between cells even if they have not directly experienced the force

Question 26

Describe stage three (effector response) of mechanotransduction

Answer 26

- precise response at the cellular level to elicit suitable change/adaptation - cells within the tissue accurately respond to the Load - the nature of this effects reposed is determined by how the load is applied (magnitude, duration, type, speed)

Question 27

How do effector cells respond to

Answer 27

- by up regulating protein synthesis to drive adaption - durign rehab, your patients will add tissue or modify it to optimally perform the task and to withstand the stress they will encounter in the future

Question 28

List the 5 steps involved in mechanotransduction

Answer 28

1- tissue load 2- stimalyes transcription factors 3- stimulates gene expression 4- stimulates protein synthesis 5- the synthesised protein reflects the original stimulus

Question 29

What are the different mechanisms of cell communication which permit the processes for mechanotransduction to occur

Answer 29

- gap junctions - chemical messengers - endocrine signalling - paracrine signalling - autocrine signalling