Homeostasis Flashcards
What are tissues?
Groups of cells that share the same characteristics or specializations
What are organs?
Collection of tissues, usually of several different type, that synchronise to perform a particular function
What do all cells require in order to survive?
Energy
Preventing disturbance to the system is maintaining what?
Homeostasis
What is physiology?
The study of the body working in harmony
What is pathology?
The study of the body not working in harmony - i.e when something goes wrong
What systems co-ordinate and control all other systems in the body?
Nervous and endocrine
Maintaining optimum internal environment within the body for all cells to function is known as what?
Homeostasis
Failure to regulate changes to our bodies internal environment results in what?
Disturbance to the system pathology
The body usually has a range within which it can tolerate change… true or false?
True
What are some common everyday changes to our internal environment?
External temperature, diet, exercise
At extremes of variables what happens to homeostasis?
It is disturbed/ it becomes less effective
Through what control system is the basis of homeostasis usually controlled by?
Negative feedback
The magnitude of the generated response in negative feedback is in proportion to what?
The magnitude of the generated signal and the magnitude of the difference from the normal
What is the aim of negative feedback?
To restore the internal environment to optimal conditions
What picks up the stimulus to change?
Receptor
What are homeotherms?
Us
What is a characteristic of negative feedback?
it restores the regulated varibale AFTER ir initial displacement but cannot PREVENT it from happening
Are feed forward systems, more of less sophisticated than negative feedback?
More sophisticated
Why are feed forward systems more sophisticated?
because to some extent they can predict and even prevent change
In feed forward what permits the system to anticipate change?
Additional receptors
What is positive feedback the opposite to?
Negative feedback
What do positive feedback cycles lead to?
Instability in the system/ opposite to negative feedback which aims to restore the system
Give an example of a positive feedback system in physiology?
Action potential - Na+ influx leads to a higher permeability to Na+
Usually is positive feedback associated with physiology or pathology?
Pathology
How much of our body does water make up?
60%
Why is homeostatic maintenance of water overall crucial?
Because it determines the concentration of everything else in the body!
How is input regulated in maintaining water balance?
Thirst mechanism
How is output regulated in maintaining water balance?
Urinary losses
Anything that enters the cell needs to pass through what?
Plasma membrane
What is too large to fit through the capillary membrane?
Plasma proteins
How are drugs distributed as a fraction throughout our bodies?
1/3 ECF and 2/3 ICF
What has less water content muscle or fat?
Fat
Why are females ‘less wet’?
Because they have a higher proportion of body fat
Why are older people less wet?
Because both sexes show a decline in body water with age as muscle matt decreases and muscle contains alot of water
What is plasma?
The fluid component of blood
What are the three things that can be measured directly using the dilution principle?
Plasma Volume
Extracellular Volume
Total Body Water
How would you measure ISF if you had ECF and PV?
ISF = ECF - PV
How would you measure ICF if you had TBW and ECF
ICF = TBW - ECF
Why is it so important to maintain ECF constant?
To maintain homeostasis
Hyper means
Greater than normal
Hypo means
Less than normal
Aemia /emia means
in the blood
Uria means
in the urine
Gly means
Related to glucose
