Active Cellular Physiology

Question 1

How do soft cells keep their shape

Answer 1

• water
• uses a gradient concentration

Question 2

Epipithelial cell ____ the _____ and the ____ (and what is their appearance)

Answer 2

Line
GI tract
Airway
Cubical appearance that is maintained by water

Question 3

What provides structure for soft cells

Answer 3

Osmotic pressure

Question 4

Composition of water and solids in biological males

Answer 4

Water = 60%
- ICF - 33%
- ECF - 21.5%
- Plasma - 4.5%
- Other bodily fluids <1%

Solids = 40%
- organic and inorganic materials

Question 5

Composition of water and solids in biological females

Answer 5

Water = 50%
- ICF - 27%
- ECF - 18%
- Plasma - 4.5%
- Other bodily fluids <1%

Question 6

Why do males have a higher water concentration

Answer 6

There is more water in muscles and men have a higher muscle mass

Question 7

How much water is lost / absorbed into ECF

Answer 7

Gained:
300ml metabolic water
2200ml water absorbed across digestive epithelium (drunk)

Lost:
1150ml water Vapor lost at skin and lungs
150ml lost in feces
1200ml water lost in urine
Water secreted by sweat glands (variable

Question 8

Isotonic solution

Answer 8

When the ECF and ICF are in balance

Question 9

Why is the volume of the ICF larger then ECF

Answer 9

• water held within cells represents a significant reserve that can prevent sudden changes in solute and water concentrations in the ECF

Question 10

Hypertonic

Answer 10

• water loss from ECF decreases volume and makes the solution hypertonic in respect to the ICF
• solutes stay the same therefore higher conc of solutes for a given volume = osmotic conc of EDF has increased
• water moves from low conc of solutes in ICF to restore osmotic equilibrium
• volume will decrease so the cells are shriveled

Question 11

HYPOTONIC

Answer 11

• water moves from low concentration of solutes in ECF to ICF to restore osmotic equilibrium
• cell will swell

Question 12

HYPONETREMIA

Answer 12

• too little NA+

Question 13

Ion absorption

Answer 13

Occurs across the epithelial lining of the small intestine and colon

Question 14

Ion reserves

Answer 14

Primarily in the skeleton

Question 15

Ion pool in bodily fluids

Answer 15

ICF + ECF

Question 16

Ion Excretion

Answer 16

Primary site of ion loss: Kidneys
Secondary site of ion loss: Sweat gland secretions

Question 17

How are the concentrations of ions in the bodily fluids regulated

Answer 17

• ion excretion
• ion absorbtion
• ion storage

Question 18

Editable tissues

Answer 18

• neurons and muscle - excitable membrane potential
• epithelial cells - membrane potential (not excitable)

Question 19

Sizes of Na+ and K+

Answer 19

Na+ is smaller

Question 20

Examples of cations and anions present in and out of the cell

Answer 20

cations:
- sodium
- potassium
- calcium

Anions:
- chloride
- proteins

Question 21

Why can’t the charged particles freely flow through

Answer 21

Lipids bylayer is an insulator to prevent the freee flow of anions and cations

Question 22

Cations and Anions and membrane movement

Answer 22

• balancing Na+ and K+ and Cl- is important for maintaining ionic equilibrium
• plasma membrane seperatges the inside and outside of the cell
• cations and anions can only move across the membrane through specific channels

Question 23

What creates a membrane potential

Answer 23

The distribution of ions creates electricity
- there charge difference between the two sides

Question 24

Resting membrane potential in living cells

Answer 24

-70mV

Question 25

Why can’t ions freely pass through the membrane

Answer 25

- ions can not freely pass the plasma membranes because they are charged

Question 26

How do ions pass through the plasma membrane

Answer 26

They use membrane channels or active transport mechanism

Question 27

Concentration of Ka+ and Na+ on either side of the membrane and the ratio during resting membrane potential

Answer 27

ECF : - High Na+ - Low K+ ICF: - Low Na+ - High K+ 3Na+ in ECF and 2K+ in ICF

Question 28

How is RMP maintained

Answer 28

Passive forces such as chemical gradients Active processes su h as the ATP requiring sodium-potassium pump

Question 29

Sodiums and potassium’s size and direction of electrochemical gradient

Answer 29

Sodium: - gradient is inwards - Large electrochemical gradient Potassium: - slightly outwards - Smaller electrochemical gradient

Question 30

When membrane potential increases greater the -70 (-60,-50,-10) what is it called

Answer 30

Depolarisation: - where a chemical stimulus opens sodium channels and sodium is transported INTO of the cell (Once stimulus is removed, repolarisation occurs and RMB is restored)

Question 31

When membrane potential decreases from -70mV (-80,-90) what is it called

Answer 31

Hyperpolarisation: - where potassium channels open and more potassium ions leave the cell

Question 32

Electrical graidient vs chemical gradient

Answer 32

Chemical gradient: determined by the conc of ions across memebrane Electrical gradient: determined by the potential difference of ions across a membrane (charge difference between ICF and EFC)