Biomechanics - Regulation Flashcards
(32 cards)
What must organisms be able to do?
Maintain and regular their internal environment despite changes in the external one
What is the mechanism used to maintain a more stable internal environment?
Homeostasis
Is the internal environment constant?
No, it does change slightly but homeostasis is the process to reduce this change
What are the three functional components of homeostasis? What do they do?
- Sensor: to detect change from some internal variable
- Control centre: processes data from sense and initiate response
- Effector: to implement the response
What is the normal value or range of variables called? What is it set by?
Set point, determined by control centre
How does a change in the set point create a response?
Change in the ‘value’ of the variable creates stimulus which is measured by sensors and is detected by control centre which then creates response to return it back to its set point
What kind of process is homeostasis? What is this?
Negative feedback, when something changes creating a response to counteract the change
What part of the brain controls the body temperature?
hypothalamus
What are the sensors in the body? Where are they in the body?
Nervous system (e.g. neurons), in blood vessels, sweat glands and muscles
What does control and coordination of homeostasis depend on?
The endocrine system and nervous system
What does the endocrine system do?
Transmit chemical signals (e.g. hormones) to respective cells throughout blood through the blood
Signalling by hormones and nervous system differ?
Hormone: affect on or more regions throughout the body, is slow acting but has long lasting effects but only affects cells which has receptors for it
Nervous system: transmit between specific locations giving individual information based on pathway, info transferred very fast and is received by only neurons, muscle cells and endocrine cells
What do physiological systems of animals operate in?
A fluid environment
what does the operation of physiological in fluids require in terms of maintaining?
Concentration of water and solutes must be maintained within narrow limits
What is the maintaining of water and solutes in the body called? What is this process largely based on?
Osmoregulation, based on controlled movement of solutes between internal fluids and external environment
What is osmolarity?
The solute concentration of a solution and determines the movement of water across a selectively permeable membrane
What are the three different types of solutions and what is their water movement?
- Iso-osmotic: osmotic concentration is equal so no net flow of water
- hypo-osmotic: where there is high H2O concentration/low solute concentration and this flows to hyper-osmotic solutions which has a low H2O concentration/high solute concentration
What do the cells selectively permeable membranes do?
Seperate the intracellular medium (e.g. cytoplasm) from the extracellular medium (interstitial fluid)
How is the osmolarity of interstitial fluid mainly determined by?
The concentration of sodium ions (e.g. salt)
What is the water balance of humans as day? What makes this up?
2.5L in, 2.5L out
In: liquids = 1.5L, food = 0.75L, metabolism = 0.25L
Out: Urine = 1.5L, evaporation = 0.9L, faeces = 0.1L
What are the function of the kidneys?
Water and salt homeostasis by filtration, reabsorption, secretion and excretion
Briefly describe the functions of the kidney
Filtration: pressure filtering of body fluids
Reabsorption: reabsorbing valuable solutes
Secretion: separating the toxins + other solutes from body fluids and transporting to the bladder
Excretion: removal of the toxins from body
Explain how filtration works
The blood pressure forces fluid from blood into the tubule of the nephron where the amount of water and salt that are reabsorbed are controlled by vasopressin and aldosterone
What is a nephron?
A function unit of a kidney where blood flows into a filtration unit and the filtrates flow down a filtration tube while getting reabsorbed based on its permeability
