Physiology

Question 1

What is physiology?

Answer 1

Understanding the mechanisms of living things and how things work in the body

Question 2

Homeostasis

Answer 2

Everything kept in balance, uses dynamic equilibrium

Question 3

How do signals travel around body to maintain homeostasis? (2)

Answer 3

• Nervous system
• Hormonal (endocrine) system

Question 4

Essential components of negative feedback loop (5)

Answer 4

• Controlled variable
• Receptors (sensors)
• Processor (compare to set point)
• Set point
• Effector mechanisms (to restabilize)

Question 5

Controlled variable

Answer 5

• Starting problem (independent variable… sorta)
• ex. core body temperature, blood pressure, blood glucose, osmolarity of plasma, blood oxygen levels

Question 6

Effector mechanism

Answer 6

Changes to restore homeostasis
- ex. heart rate, urine concentration, respiratory rate

Question 7

What can and cannot diffuse across cell membrane?

Answer 7

• Yes: small gases along concentration gradient, water
• No: sugars, proteins, ions

Question 8

What causes liquids to diffuse across membrane (Brownian motion) (3)

Answer 8

• Thermal motion and collisions
• Down concentration gradient
• Inversely related to size
• Only small distances

Question 9

Pores

Answer 9

always open, non selective, any small ion

Question 10

Channel definition and the 2 types of channels

Answer 10

selective to 1 type of ion
- Non-gated: always open
- Gated: open only when stimulated by voltage, ligand (chemical signal), or sec (second messenger)

Question 11

Carriers

Answer 11

• Facilitated passive transport (relying on 1 concentration gradient
• Specific binding
• Confirmational change
• Releases 1 ion at a time

Types: 1 ion in, 2 ions in, 1 out/1in

Question 12

Pumps

Answer 12

Active transport w/ATP

Question 13

Electrochemical gradient purpose

Answer 13

Allows passive transport. Important for the passage of solutes which impacts cell function

Question 14

Osmosis

Answer 14

How water moves across body compartments
- ECF pressure maintained by homeostatic mechanisms. ICF changes depending on ECF

Question 15

Molarity

Answer 15

grams of solute/1L

Question 16

Osmol

Answer 16

number of particles

Question 17

Osmolarity

Answer 17

measure of solvent activity (Number of osmoles/ unit volume of solution)
- higher osmolarity, lower solvent activity

Question 18

Osmosis

Answer 18

Movement of water from higher solvent activity to lower solvent activity across semipermeable membrane

Question 19

Osmotic pressure

Answer 19

Exact pressure required to stop osmosis

Question 20

Effective osmotic pressure cause

Answer 20

• Depends on properties of membrane separating compartments
• O=1, not permeable
• O=0, freely permeable
• O=0-1, varying permeability

Question 21

Tonicity

Answer 21

Effect of bathing solution on cell volume

Question 22

Isotonic

Answer 22

No net movement

Question 23

Hypertonic

Answer 23

Net outwards, shrinking

Question 24

Hypotonic

Answer 24

Net movement inwards, lysis

Question 25

Starling’s forces

Answer 25

Determine how much water moves in and out of capillaries (based on oncotic (in) pressure and constant hydrostatic pressure (out)

Question 26

How much of the animals body is water?

Answer 26

60%

Question 27

How much water is ICF

Answer 27

40%

Question 28

How much water is ECF

Answer 28

20%

Question 29

Gibbs-Donnan Effect

Answer 29

• ICF negative charge drawing in positive ions and water
• Cells combat this using 3NA/2K pump