Physiology Flashcards
Hypokalemia
K+
Hyperkalemia - more of a concern- muscle weakness/paralysis. cardiac arrythmia - usually arises from kidney failure and inabilty to secrete K+ TOO MUCH Potassium
is when blood’s potassium levels are too low. Potassium is an important electrolyte for nerve and muscle cell functioning, especially for muscle cells in the heart. Your kidneys control your body’s potassium levels, allowing for excess potassium to leave the body through urine or sweat.
Plasma normal range?
It makes up about 55% of the body’s total blood volume.
3.5 - 5 to maintain membrane potential
??
electrogenic? producing a change in the electrical potential of a cell.
moving K+ out of cell, creates a charge imbalance “electrogenic”
receptor potential?
mechanosensors, olfactory receptors, photoreceptors
Plasma osmolalaity?
295-300 miile osmoles/KG
what human cells do not reproduce?
neurons, heart cells, skeletal muscle cells and red blood cells.
can smooth muscles reproduce?
Yes - Smooth cells have the greatest capacity to regenerate of all the muscle cell types. The smooth muscle cells themselves retain the ability to divide, and can increase in number this way. As well as this, new cells can be produced by the division of cells called pericytes that lie along some small blood vessels.
autocoids?
autocoids” are biological factors (molecules) which act like local hormones, have a brief duration, and act near their site of synthesis.
Paracrine signaling
is a form of cell signaling or cell-to-cell communication in which a cell produces a signal to induce changes in nearby cells, altering the behaviour of those cells.
operons?
An operon is made up of several structural genes arranged under a common promoter and regulated by a common operator. It is defined as a set of adjacent structural genes, plus the adjacent regulatory signals that affect transcription of the structural genes.
Signal transduction
(also known as cell signaling) is the transmission of molecular signals from a cell’s exterior to its interior. Signals received by cells must be transmitted effectively into the cell to ensure an appropriate response. This step is initiated by cell-surface receptors.
what’s in a cell? H2O
PMP
water - 2/3 of body’s water, and high in potassium, magnesium, phosphate
ecm? rich in?
1/3 water, large amounts of sodium, chloride, bicarbonate, oxygen, glucose, fatty acids, amino acids, carbon dioxide
body mass - % water?
60%
feedback system of body - 3 parts
receptor - reports to Central Control,
control center (brain or endocrine) evaluates and sends out orders,
effector - receives orders and complies
negative feedback in body
if something is excessive or deficient - attempts to return things to normal
positive feedback - leads to?
INstability - initiating change - ie blood clotting is good to stop a rupture, but it needs to stop or it can do bad things
cell membranes - allow lipid soluable substances to enter like?
CO2, O2, fatty acids, steriod hormones
keeps out water soluable - ions, glucose, amino acids
cell membrane made of mainly?
lipids and proteins - proteins fulfull many roles - trasnport, enzymes, hormones, antigens, ion and water channels, etc
amphipathic
glycerol backbone head, two fatty acid tails -
both hydro phillic and phobic
how does cholesterol affect cell membrane?
As temperature increases, so does phospholipid bilayer fluidity.
increases flex and stability, controls fluidity depending upon temperature -
Cholesterol reduces permeability of lipid membranes. … Cholesterol plays has a role in membrane fluidity but it’s most important function is in reducing the permeability of the cell membrane. Cholesterol helps to restrict the passage of molecules by increasing the packing of phospholipids.
protein components of cell membrane?
integral (channels, pores, transport proteins, receptoss G proteins)
peripheral - loosely attached to intra or extra cellular side by electrostatic interaction - not covalently bound
transport into/out of cell - 3 types
- bulk
endocytosis - pino, phago, receptor mediated
exocytosis
- passive - simple or facilitates (w carrier) NO ATP reqa
- Active - Uphill transport - needs energy - primary and secondary
pinocytosis - bring things into cell
vesicles formed -
via clathrin coating, latticework of actin and myosin - ATP and Ca++ required (to pinch)