Physiology Flashcards
Define homeostasis.
Cells and tissues have to keep a state of equilibrium within a set range.
What is the range?
What the body perceives to be normal.
Name the 3 types of communication.
Autocrine cell to cell.
Paracrine cell to tissue.
Endocrine cell to the whole body.
What are the steps to a negative feedback loop?
- Sensor detects and measures a parameter.
- Internal set point acts as a comparator.
- Output signal changes paramater back to set point
- Ouptut activates effector.
What happens in more complex loops?
Can have synergistic and antagonistic loops, as well as multiple loops for one parameter if it’s very important.
What do adaptation and acclimatisation mean?
Where the range for a parameter changes due to exposure to an extreme for a long time.
What causes homeostasis?
Change in a stimulus. Chemical, electrical or mechanical.
What makes up body fluid?
Extracellular fluid - interstitial and plasma. Intracellular fluid. Urine, vaginal and seminal fluid etc.
What is a solvent?
What is a solute?
A solvent is fluid in the body.
A solute is dissolved substances in water.
What is the distribution of bodily fluids?
42 litres in total, 26 is intracellular, 13 of interstitial and 3 of plasma. 5 litres of blood in total.
What is blood plasma?
Blood consists of plasma and cells. Cells do not dissolve so only plasma classed as bodily fluid.
Name some electrolytes in body fluid.
Name some non-electrolytes in body fluid.
Ca2+, K+, Cl-, proteins and organic ions.
Glucose, phospholipids, cholesterol and urea.
Roles of fluid in the body?
Transport, site of reactions, lubrication, cushioning and regulation of temp by sweating.
What are electrolytes needed for?
Cell signalling, action potentials, acid-base balance, muscle contraction and osmosis.
What happens if there is disruption to body fluids?
Dehydration if too little water. Hyponatraemia - too much water which dilutes electrolytes, oedema from too much water, swelling from a vascular compartment in interstitial space.
