Summary of the De Nier, based on the slides of the colleges. This course is (usually) given in the third year of the study of Medical Sciences and Technology, or for students with a basic course of Basic Tissue Engineering at TU / e.
Test Bank For Medical Physiology, 3rd - 2017 All Chapters - 9781455743773
Class notes BIO413 Medical Physiology
Class notes BIO413 (bio5413) Medical Physiology med phys notes
All for this textbook (10)
Written for
Technische Universiteit Eindhoven (TUE)
Medische Wetenschappen en Technologie
De nier
All documents for this subject (1)
4
reviews
By: oanacorina13 • 2 year ago
By: woutervk72 • 5 year ago
By: camielkerckhaert • 6 year ago
By: jeroenvanengelen • 7 year ago
Seller
Follow
liisa
Reviews received
Content preview
De Nier
Jaar 3, kwartiel 1
College 1: introduction
Silverthorn, chapter 5 – osmosis and tonicity
Boron & Boulpaep, chapter 33
Homeostase
- Regulation of the body’s internal environment
- Keeping internal environment stable
- Interaction between outside world extracellular fluid intracellular fluid
Homeostasis - definitions
- External or internal change
- Loss of homeostasis - sensed by organism
- Successful compensation homeostasis reestablished
- Study of compensation is physiology
- Failure to compensate disease
- Study of failure to compensate is pathophysiology
Mass balance in an open system
Input (metabolic production) body load output (metabolism to a new substance)
Law of mass balance: mass balance = existing body load + intake or metabolic production - excretion
or metabolic removal
Intake 2.2 L/day + metabolic production 0.3 L/day - Output 2.5 L/day = 0
Diffusion: properties
- Passive process
- High concentration to low concentration
- Chemical gradient
- Net movement until concentration is equal
- Equilibrium
- Rapid over short distances
- Directly related to temperature
- Inversely related to molecular weight and size
- In open system or across a partition (a membrane)
Fick’s law of diffusion
Rate of diffusion = surface area x concentration gradient x membrane permeability
Membrane permeability = lipid solubility/molecular size
Changing the composition of the lipid layer can increase or decrease membrane permeability.
Cell membrane is negatively charged because of the phosphate groups of the phospholipids.
Factors affecting rate of diffusion through a cell membrane:
- Lipid solubility
- Molecular size
- Concentration gradient
- Membrane surface area
- Composition of lipid layer
Osmose:
1
,Stofje dat niet door het membraan kan diffunderen, daar diffundeert water naar binnen.
Stofje dat wel door het membraan kan diffunderen, daar diffunderen de stofjes uit.
Body fluid compartments
The body fluids in two compartments: the extracellular fluid (ECF) and intracellular fluid (ICF).
The ECF and ICF are in osmotic equilibrium but have very different chemical composition.
ICF is 2/3 of the total body water volume. Material must cross the cell membrane.
ECF includes all fluid outside the cells. The ECF is 1/3 of the body fluid volume. The ECF consists of:
- Interstitial fluid (IF), which lies between the circulatory system and the cells, is 75% of the
ECF volume.
- Plasma, the liquid matrix of blood, is 25% of the ECF volume. Substances moving between
the plasma and interstitial fluid must cross the leaky exchange epithelium of the capillary
wall.
Water distribution and composition
Homeostase does not mean equilibrium
- Osmotic equilibrium
- Chemical disequilibrium
- Electrical disequilibrium
Two compartments are separated by a membrane that is permeable to water
but not glucose, where solution B is more concentrated than solution A.
Water moves by osmosis into the more concentrated solution.
Osmotic pressure is the pressure that must be applied to B to oppose
osmosis.
Osmolarity: the concentration of a solution expressed as the total number of solute particles per
liter.
1 M glucose = 1 OsM
1 M NaCl = 2 OsM
2
,Hyposmotic: smaller OsM
Isosmotic: same OsM
Hyperosmotic: bigger OsM
Tonicity: the ability of an extracellular solution to make water move into or out a cell by osmosis.
Solution is hypotonic cell in solution swells
Solution is isotonic cell in solution doesn’t change in size
Solution is hypertonic cell in solution shrinks
Rules for osmolarity and tonicity:
1. Assume that all intracellular solutes are nonpenetrating
2. Compare osmolarities before the cell is exposed to the solution. (at equilibrium, the cell and
solution are always isosmotic)
3. Tonicity of a solution describes the volume change of a cell at equilibrium
4. Determine tonicity by comparing nonpenetrating solute concentrations in the cell and the
solution. Net water movement is into the compartment with the higher concentration of
nonpenetrating solutes.
5. Hyposmotic solutions are always hypotonic.
Buffers
Buffer of blood : pCO2-bicarbonate-system
CO2 + H20 ↔ H2CO3 ↔ H+ + HCO3-
The pH of blood is directly dependent of the ratio of HCO3 and CO2 Henderson-Hasselbach
equation:
[𝐻𝐶𝑂 ]3
pH = pKa + log10 0.03 ∙ 𝑝𝐶𝑂
2
Buffer systems
Extracellular:
- Bicarbonate CO2 (~25 mmol/L)
- Phosphate (~1 mmol/L)(H2PO4- ↔ H+ + HPO42-)
- Protein
Intracellular:
- Proteins (erythrocytes: hemoglobin)
- Organic and inorganic phosphates
- Bone
Acidosis or alkalosis? Metabolic or respiratory?
Acids and alkalis (bases)
3 mechanisms to buffer pH changes:
- Chemical buffering (seconds)
- CO2 (volatile acid) exhaled via lungs
(minutes to hours)
- Non-volatile acid (sulfate and
phosphate) and H+ excretion or base
retention via kidney (hours to days)
4
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller liisa. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $5.88. You're not tied to anything after your purchase.
