Physiology: Cellular Function Flashcards
Body Composition
Total Body Weight = 60% body water + 40% solids
Water: ECF = 20% (15% interstitial + 5% plasma) + ICF = 40%
TBW decreases with age
TBW increased in males
Name the buffers in the blood
- Hb- Histidine residues. Deoxygenated Hb is better
- Plasma proteins: albumin
- Bicarbonate (Carbonic Acid)
How does 3. work? -> Carbonic Anhydrase increases the speed of the reaction
How does Bicarbonate (Carbonic Acid) work?
Carbonic Anhydrase increases the speed of the reaction
Describe Cell Transport across the cell membrane
Transport across cell membrane
PASSIVE
Diffusion
Facilitated diffusion
ACTIVE
Endo/exocytosis
Ion channels (Ligand/voltage/mechanical)
Active Transport
SECONDARY ACTIVE TRANSPORT
The movement of a substance A along its electrochemical gradient provides energy to transport substance B against its electrochemical gradient e.g. Sodium/glucose or Sodium/Amino Acids -> Co transporters: Sodium/Calcium++, H+/Ions
What hormones DECREASE BSL?
Decreasing BSL = Insulin and Insulin Growth Factors 1 and 2
Glucose uptake in all tissues
Glycogenogenesis Liver Glucose -> Fat
What hormones INCREASE BSL?
Increasing BSL = Catecholamines, Glucagon, Growth Hormone, Cortisol, Thyroid
Catecholamines – beta receptors, CAMP à Glycogenolysis and gluconeogenesis
Glucagon – beta receptors, CAMP à Glycogenolysis and gluconeogenesis
Growth Hormone – Insulin block and Gluconeogenesis in liver
Cortisol – As for catecholamines
Thyroid – Increased absorption, increased glycogenosis and increased insulin breakdown
How is glucose metabolized?
Aerobic
Anaerobic
Glycogen
Pentoses
Types of Immunoglobulins
Types and significance
A – Secretory
D – Antigen recognition by B cells
E – Anaphylaxis, histamine release from basophils and mast cells
G – Complement activation/Infection
M – Complement activation/Infection (produced first)
Features of Innate Immunity
1) Triggered by cellular receptors
2) Activate defense mechanisms:
a) Phagocytosis
b) Interferons
c) Complement System
3) Important in early responses to infection
(Nonspecific defense mechanism. Immediately or within hours of antigen appearances in body)
Features of Acquired Immunity
1) T Lymphocytes
- APCs, MCHs, HLA
- Proliferate and produces cytokines
2) B Lymphocytes
- Form clones to produce antibodies
3) Memory Cells
- Antigen specific immune response system creates army specifically designed to kill that antigen complex
Intercellular communication
Via:
Gap junctions
Chemical messengers : neural, endocrine, paracrine
Autocrine (affect same cell by which it is secreted)
Juxtacrine (direct contact with nearby cell)(Paracrine affects nearby cells)
Receptors response to variations in messengers:
Increase in messenger can cause a decrease in receptors: Down Regulation
Decrease in messenger can cause an increase in receptors: Up Regulation
How do messengers act?
1) Ion channels, transcription of MRNAs
2) Activation of phospholipase C
3) Production of cAMP/cGMP
4) Increase activity of tyrosine kinase/serine/threonine kinase
What are the principal ketones?
a) Acetone
b) Acetoacetate
c) Beta-hydroxybutyrate
Production/Metabolism of Ketones
Site – Mitochondria -> Liver/other tissues
Substrate – Fatty acids/Acetyl-CoA
Mechanism – High energy process.
Beta oxidation of fatty acids and acetyl CoA -> acetoacetyl CoA
In Liver – Acetoacetyl CoA -> Acetoacetate
Acetoacetate -> Beta hydroxybutyrate + acetone (excreted in urine & breath.)
Accumulation of Ketones in body = Ketosis -> metabolic acidosis
(Causes include Diabetes/Starvation/High fat low carb diet)
What is normal serum osmolality?
280-300 mOsm/L
