Basic Concepts in Human Physiology

Question 1

What is Intracellular Fluid

Answer 1

Fluid inside the cells

Question 2

What is Extracellular Fluid

Answer 2

Fluid outside of the cells

Question 3

What is Plasma

Answer 3

The liquid component of blood

Question 4

3 Major Compartments

Answer 4

1. Intracellular Fluid
2. Interstitial Fluid
3. Plasma

Question 5

Extracellular Fluid is made

Answer 5

1. Interstitial Fluid
2. Plasma

Question 6

How does the concentration of ions (electrolytes) differ between ICF?

Answer 6

ECF: Higher in sodium ions (Na+) and calcium ions (Ca2+)
ICF: Higher in potassium ions

Question 7

Function of interstitial fluid

Answer 7

1. Acts as a medium for the exchange of substances between blood and cells
2. Helps to maintain a stable environment for cellular function

Question 8

What is a simple diffusion

Answer 8

1. The movement of particles from an area of high concentration to an area of low concentration
2. It is a passive process, meaning it does not require energy

Question 9

Factors that affect the rate of diffusion?

Answer 9

1. Temperature
2. Particle Mass
3. Surface area of the membrane
4. Medium

Question 10

How does temperature affect the rate of diffusion?

Answer 10

Higher temperatures increase the rate of diffusion as it increase the kinetic energy of particles

Question 11

How does particle mass affect the rate of difussion?

Answer 11

Smaller particles diffuse faster than larger particles

Question 12

How does the surface area of the membrane affect the rate of diffusion?

Answer 12

A larger surface area provides more space for particles to move across increases the rate of diffusion

Question 13

How does the medium affect the rate of diffusion?

Answer 13

Diffusion is faster in gases than in liquids due to the greater spaces between particles in a gaseous state

Question 14

Define osmosis?

Answer 14

The movement of water across a semipermeable membrane
Water moves from a region of low solute concentration to a region of high solute concentration

Question 15

How are osmolarity and water concentration related?

Answer 15

Lower solute concentration + higher water concentration = lower osmolarity
Higher solute concentration + lower water concentration = higher osmolarity

Question 16

What is the formula for calculating osmotic pressure?

Answer 16

Osmotic pressure = CRT

C = total solute concentration (molarity x number of particles the solute dissociates into in water)

R = universal gas constant (0.082 L atm/mol Kelvin)

T = temperature in Kelvin (+273)

Question 17

Define Isoosmotic?

Answer 17

Two solutions with the same osmolarity

Question 18

Define Hyperosomotic?

Answer 18

A solution with a higher osmolarity compared to another

Question 19

Define Hypoosmotic?

Answer 19

A solution with a lower osmolarity compared to another

Question 20

Explain how age can influence total body water content

Answer 20

Newborns have the highest body water content at about 75%, while the elderly can have as low as 45%. This decline in body water content with age is a natural physiological change

Question 21

Explain how gender can influence total body water content

Answer 21

Adult males typically have a higher body water percentage (~58%) compared to adult females (~48%). This difference is primarily due to the generally higher proportion of muscle mass in males, as muscle tissue holds more water than fat tissue.

Question 22

Explain how body composition can influence total body water content

Answer 22

Individuals with a higher proportion of lean body mass (muscle) will have a higher body water percentage than those with a higher percentage of body fat. This is because muscle tissue has a higher water content than adipose (fat) tissue.

Question 23

Calculate the osmotic pressure of 3M CaCl2 at 18 Celsius?

Answer 23

C: CaCl2 dissociates into 3 particles so it is ( 3 x 3 = 9)
R: 0.082 L atm/mol degrees Kelvin
T: (18 + 273 = 291)
Osmotic Pressure: ( 9 x 291 x 0.082 = 214.758 atm)

Question 24

Calculate the osmotic pressure of 1 M sucrose at 20 Celsius?

Answer 24

C: 1M → cannot dissociate
R: 0.082 L atm/mol degrees Kelvin
T: ( 20 + 273 = 293 K)
Osmotic Pressure: ( 1 x 0.082 x 293 = 24.026)

Question 25

Calculate the osmotic pressure of 154mM NaCl at 18 Celsius?

Answer 25

C: (0.154 x 2 = 0.308) R: 0.082 L atm/mol degrees Kelvin T: (18 + 273 = 291K) Osmotic Pressure: ( 0.308 x 0.082 x 291 = 7.35 atm)

Question 26

What are the two main types of mediated transport proteins?

Answer 26

Channel and Carrier Proteins

Question 27

What is the difference between channel and carrier proteins?

Answer 27

Channel proteins: passive transport, form a fluid-filled pore in the membrane, many are "gated" so they can open or close Carrier proteins: can be active or passive, work by changing shape, pick up and take substances through the membrane

Question 28

What are the types of carrier proteins?

Answer 28

Uniporters, symporters and antiporters

Question 29

What is facilitated diffusion?

Answer 29

Passive transport that uses carrier proteins to move molecules from high to low concentration.

Question 30

What factors affect the rate of facilitated diffusion?

Answer 30

1. Total number of transporters in the membrane 2. Rate at which conformation change can occur 3. Extent to which sites are saturated by molecule transported 4. Temperature

Question 31

What is primary active transport?

Answer 31

Requires energy (ATP hydrolysis) to transport molecules from a low concentration to a high concentration. Uses carrier proteins that change conformation but only in one direction

Question 32

What is secondary active transport?

Answer 32

Uses the concentration gradient of one molecule (e.g., Na+) to drive the transport of another molecule (e.g., glucose) from low to high concentration

Question 33

What are endocytosis and exocytosis

Answer 33

Processes that transport molecules without requiring them to pass through the cell membrane.

Question 34

Further explain endocytosis

Answer 34

Engulfing substances from outside the cell. Phagocytosis: Engulfing a solid particle.

Question 35

Further explain exocytosis

Answer 35

Releasing substances from inside the cell.

Question 36

What is epithelial transport?

Answer 36

Transport across epithelial cells, which line hollow tubes and organs of the body. Different sides of the epithelial cell have different properties

Question 37

What is Homeostasis?

Answer 37

Maintenance of a stable internal environment. Ensures optimal function.

Question 38

What are biological set points?

Answer 38

Normal ranges for physiological variables, such as body temperature (36.1 → 37.2 Celsius) and fasting blood glucose (4 → 7 mmol/L)

Question 39

What are the two types of feedback mechanisms?

Answer 39

Negative and Positive Feedback

Question 40

Further explain Negative Feedback and include an example

Answer 40

The response causes a change in the opposite direction of the stimulus. Example: body temperature regulation.

Question 41

Further explain positive feedback and include an example

Answer 41

The response causes a change in the same direction as the stimulus, amplifying the effect. Examples: childbirth, the ovary in the menstrual cycle.

Question 42

How does feedback control hormone secretion?

Answer 42

Target cells can provide feedback signals to reduce hormone secretion once the hormones have elicited their effects.

Question 43

What factors causes variation in body water content?

Answer 43

1. Age 2. Gender 3. Body Composition