Cells Flashcards
Water distribution: how much water is there in:
a) the ECF (extracellular fluid)?
b) the ICF (intracellular fluid)?
a) 14L [1/3 body water]
b) 28L [2/3 body water]
Water distribution: how much water is there in the (ECF):
a) interstitial fluid
b) plasma
a) interstitial - 11L
b) plasma - 3L
What is the predominant electrolyte(s) in the ICF?
K+
What is the predominant electrolyte(s) in the ECF?
Na+, Cl-, HCO3-
What is the definition of osmosis?
Movement of H2O across a partially permeable membrane from an area of high water potential to an area of low water potential.
What is the definition of osmolarity?
The number of solute particles per L of fluid. (A high osmolarity has more solute particles per L).
What is the definition of osmotic pressure?
The pressure that must be applied to a solution to prevent inward osmosis through a partially permeable membrane.
What is the definition of oncotic pressure?
A form of osmotic pressure exerted by proteins, notably albumin, that tends to pull fluid into its solution.
What is the function of rough ER?
Protein synthesis
What is the function of smooth ER?
Lipid synthesis
What is the function of the golgi apparatus?
Processes and modifies ER products.
What is the cis face of the golgi apparatus?
The cis face is nearest the nucleus and receives ER vesicles.
What does the medial Golgi do?
It modifies products by adding sugars forming oligosaccharides
What does the trans face of the golgi do?
It sorts molecules into vesicles.
What are the functions of vesicles?
Transports and stores materials. These are membrane bound organelles.
What are desmosomes?
Intracellular junctions
Attach cells via the intermediate filaments.
What are tight junctions?
Binds cells together to prevent leakage of molecules in between them.
What is the function of gap junctions?
Conduct electrical signals.
Name 4 molecules you’d find in a plasma membrane.
- Cholesterol
- Glycoproteins
- Glycolipids
- Integral proteins
List 4 functions of a plasma membrane.
- Physical boundary for the cell.
- Regulates the movement of substances.
- Has receptors for cell to cell signalling.
- Attaches the cell to the external environment.
What is type 1 collagen and example?
Makes up 90% of the bodies collagen
Eg: Bone, skin and teeth.
What is type 2 collagen and example?
This type is found in elastic cartilage, which provides joint support
Eg: cartilage
What is type 3 collagen and example?
This type is found in muscles, arteries and organs.
Eg: Arteries, liver, kidneys, spleen, uterus
What is type 4 collagen and example?
This type is found in the layers of your skin.
Eg: Basement membranes
What is an example of type 5 collagen?
Placenta
Name 3 mechanisms by which a molecule can move across a plasma membrane.
- Diffusion - movement down a concentration gradient.
- Facilitated diffusion.
- Active transport - uses ATP, against concentration gradient.
Name 3 types of cell receptors.
- Ion channel receptors.
- G-protein coupled receptors.
- Enzyme linked receptors.
Name 3 ways in which we intake fluids.
- Drink.
- Food.
- IV Fluids.
Name 3 hormones involved in water homeostasis.
- Aldosterone.
- ADH - antidiuretic hormone.
- ANP - atrial natriuretic peptide.
What is oedema?
Excess H2O in the interstitial fluid.
Name the 4 types of oedema.
- Lymphatic.
- Venous.
- Hypoalbuminaemic.
- Inflammatory.
What is serous effusion?
Excess H2O in a body cavity.
If a patient has diabetes insipidus and is not producing any ADH what is her blood and urine osmolality after 3 hours of water deprivation going to look like?
Blood osmolality would be high.
Why is sodium doubled in the plasma osmolality equation?
To account for negatively charged ions.
Give 3 examples of endocytosis.
- Phagocytosis.
- Pinocytosis.
- Receptor mediated.
What is hyponatremia?
Lower than normal level of sodium in the bloodstream.
Electrolyte homeostasis: What is the cause(s) of hyponatremia and what are its risks?
Causes: Excess water due to IV fluids, diuretics.
Risks: Over hydration - headache, confusion.
What is hypernatremia?
Too high levels of sodium in the bloodstream.
Electrolyte homeostasis: what is the cause(s) of hypernatremia? And what are the risks?
Cause - water deficit (poor intake, diabetes insipidus etc).
Risks - Dehydration.
(High sodium = low H2O which dehydrates the brain).
What is hyperkalemia?
Too high potassium in the bloodstream.
Electrolyte homeostasis: What is the cause(s) of hyperkalemia and what are its risks?
Causes: renal failure, acidosis, diuretic inhibitors.
Risks: Cardiac arrest.
What is hypokalemia?
Too low potassium in the bloodstream.
Electrolyte homeostasis: What is the cause(s) of hypokalemia and what are its risks?
Causes: D+V, alkalosis, diuretics.
Risks: weakness and dysrhythmia.
What is hypercalcemia?
When calcium is too high in the bloodstream.
Electrolyte homeostasis: What is the cause(s) of hypercalcemia and what are its risks?
Causes: hyperparathyroidism, Vit D toxicity, malignancy.
Risks: renal stones and metastatic calcification.
