Basic Concepts in Human Physiology Flashcards
TB1 Year 1
What is Intracellular Fluid
Fluid inside the cells
What is Extracellular Fluid
Fluid outside of the cells
What is Plasma
The liquid component of blood
3 Major Compartments
- Intracellular Fluid
- Interstitial Fluid
- Plasma
Extracellular Fluid is made
- Interstitial Fluid
- Plasma
How does the concentration of ions (electrolytes) differ between ICF?
ECF: Higher in sodium ions (Na+) and calcium ions (Ca2+)
ICF: Higher in potassium ions
Function of interstitial fluid
- Acts as a medium for the exchange of substances between blood and cells
- Helps to maintain a stable environment for cellular function
What is a simple diffusion
- The movement of particles from an area of high concentration to an area of low concentration
- It is a passive process, meaning it does not require energy
Factors that affect the rate of diffusion?
- Temperature
- Particle Mass
- Surface area of the membrane
- Medium
How does temperature affect the rate of diffusion?
Higher temperatures increase the rate of diffusion as it increase the kinetic energy of particles
How does particle mass affect the rate of difussion?
Smaller particles diffuse faster than larger particles
How does the surface area of the membrane affect the rate of diffusion?
A larger surface area provides more space for particles to move across increases the rate of diffusion
How does the medium affect the rate of diffusion?
Diffusion is faster in gases than in liquids due to the greater spaces between particles in a gaseous state
Define osmosis?
The movement of water across a semipermeable membrane
Water moves from a region of low solute concentration to a region of high solute concentration
How are osmolarity and water concentration related?
Lower solute concentration + higher water concentration = lower osmolarity
Higher solute concentration + lower water concentration = higher osmolarity
What is the formula for calculating osmotic pressure?
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)
Define Isoosmotic?
Two solutions with the same osmolarity
Define Hyperosomotic?
A solution with a higher osmolarity compared to another
Define Hypoosmotic?
A solution with a lower osmolarity compared to another
Explain how age can influence total body water content
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
Explain how gender can influence total body water content
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.
Explain how body composition can influence total body water content
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.
Calculate the osmotic pressure of 3M CaCl2 at 18 Celsius?
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)
Calculate the osmotic pressure of 1 M sucrose at 20 Celsius?
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)
Calculate the osmotic pressure of 154mM NaCl at 18 Celsius?
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)
What are the two main types of mediated transport proteins?
Channel and Carrier Proteins
What is the difference between channel and carrier proteins?
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
What are the types of carrier proteins?
Uniporters, symporters and antiporters
What is facilitated diffusion?
Passive transport that uses carrier proteins to move molecules from high to low concentration.
What factors affect the rate of facilitated diffusion?
- Total number of transporters in the membrane
- Rate at which conformation change can occur
- Extent to which sites are saturated by molecule transported
- Temperature
What is primary active transport?
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
What is secondary active transport?
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
What are endocytosis and exocytosis
Processes that transport molecules without requiring them to pass through the cell membrane.
Further explain endocytosis
Engulfing substances from outside the cell.
Phagocytosis: Engulfing a solid particle.
Further explain exocytosis
Releasing substances from inside the cell.
What is epithelial transport?
Transport across epithelial cells, which line hollow tubes and organs of the body. Different sides of the epithelial cell have different properties
What is Homeostasis?
Maintenance of a stable internal environment. Ensures optimal function.
What are biological set points?
Normal ranges for physiological variables, such as body temperature (36.1 → 37.2 Celsius) and fasting blood glucose (4 → 7 mmol/L)
What are the two types of feedback mechanisms?
Negative and Positive Feedback
Further explain Negative Feedback and include an example
The response causes a change in the opposite direction of the stimulus. Example: body temperature regulation.
Further explain positive feedback and include an example
The response causes a change in the same direction as the stimulus, amplifying the effect. Examples: childbirth, the ovary in the menstrual cycle.
How does feedback control hormone secretion?
Target cells can provide feedback signals to reduce hormone secretion once the hormones have elicited their effects.
What factors causes variation in body water content?
- Age
- Gender
- Body Composition
