FHD - biochemistry

contains FHD topics - cell physiology and cell ions, clinical biochemistry

what is physiology 

the characteristics that contribute to a function 

what is pathophysiology

pathology in the context of physiology

what is homeostasis

a process by which biological systems maintain constant conditions in response to an altering environment

what is negative feedback 

when a change is minimised to restore normal conditions 

what is positive feedback 

when a change is amplified, leading to system instability 

what is an example in a failure of homeostasis 

blood loss in positive feedback, resulting in death 

what are fluid compartments

distinct spaces where water and dissolved substances are held

what makes up extracellular fluid

interstitial fluid, plasma, and transcellular fluid

what percentage of fluid is extracellular

33.3%

what percentage of fluid is intracellular

66.7%

what percentage of fluid is interstitial

24.7%

what percentage of fluid is plasma

6.7%

what percentage of fluid is transcellular

1.9%

what is primary active transport

transport via the use of ATP hydrolysis

how does secondary active transport work

via symporters and antiporters, where the energy for transport is created via a different gradient which acts as a driving force for ions to be pumped

what are the three rules of ionic balance

• the concentrations of positive and negative ions must nearly balance 

• any ion that leaves the cell must be replaced soon by another type of ion 

• energy is always being used to establish concentration gradients across the membrane 

what are excitable cells

cells that can produce or respond to electric signals

which solutes are cations in the body

sodium, potassium, calcium, hydrogen, magnesium

which solutes are anions in the body

hydroxide, chloride, bicarbonate, sulphate, phosphate, and charged proteins

which solutes are non ionic in the body

glucose and proteins

which ions are present in the body

potassium, sodium, chloride, bicarbonate, amino acids, calcium 

which ions are in high abundance intracellularly

• potassium is in highest abundance

• phosphate and organic anions are in relatively high abundance 

which ions are in high abundance extracellularly

• sodium is in highest abundance

• chloride is in relatively high abundance 

what is pH a measure of 

the negative logarithm of hydrogen ion concentration 

what does low pH do

stimulates proteolytic enzymes

what is carbonic anhydrase

an enzyme involved in pH homeostasis

what does carbonic anhydrase do

catalyses water and carbon dioxide to generate carbonic acid 

what can occur if a person has a potassium deficiency

hypokalaemia

what can occur if a person has a sodium deficiency

hyponatremia

what can occur if a person has a calcium deficiency

hypocalcaemia

what do parietal cells do

release HCL into the stomach

where does carbonic anhydrase act

within parietal cells

how is bicarbonate formed 

carbonic acid donates a proton to form bicarbonate 

what occurs to the proton donated from carbonic anhydrase 

is travels through ATP synthase, synthesising ATP and is then released into the lumen

how does bicarbonate leave the cell and where

via an antiporter into the plasma, causing chloride to enter

how does chloride leave the cell and where

via a channel protein into the lumen

what does omeprazole do

acts as a proton pump inhibitor via the formation of a disulphide bond 

what do oxonol dyes do 

inhibit bicarbonate by acting as a chloride antiporter 

What is analysed when testing for renal function

sodium, potassium, urea, creatinine

what is analysed when testing for liver function

total protein, albumin, bilirubin, alkaline phosphatase, alanine transaminase

what is ALT

alkaline transaminase 

what is ALP

alkaline phosphatase

what is analysed when testing for bone profile

total protein, albumin, calcium, phosphate, alkaline phosphatase

what is analysed when testing for thyroid function

TSH, T4

what is analysed when testing for lipid profile 

total cholesterol, LDL, HDL, triglycerides  

What does low TSH link to

high T4 and overactive thyroid

what does high TSH link to

low T4 and underactive thyroid

when would TSH levels not alter T4 volume 

when it is subclinical