Lecture 2: Homeostasis Flashcards
What is homeostasis?
The concept of maintaining a relatively stable internal environment.
Diagram
Internal environment refers primarily to the composition of ____ _____.
Interstitial fluid
What is interstitial fluid?
Where the cells obtain the nutrients and in which the cells eliminate the waste
The respiratory system
Brings oxygen to the cell and then removes CO2
Digestive system
Brings glucose & nutrients to the cell
Urinary system
Removes waste products
The cirulation of blood
brings nutrients to cells and removes the waste products from cells.
Name the controlled conditions that are regulated by Homeostatic control mechanisms
temperature
water balance
electrolyte balance
blood pH (level of acidity)
blood glucose level
blood pressure
Homeostatic control mechanisms
This is an internal communication between the nervous system and the endocrine system.
There are negative and positive feedback mechanisms.
Control system –(output)–> Effectors –(response)–> Receptors –(input)–> control system.
Loop is continuous^^
Receptors
Respond to a stimulus that then causes a change in a controlled condition
This is sent to the control centre - input.
Are in the nervous system.
Output
Then the appropriate response is determined
Effectors
are the means in which the control centre regulates the controlled condition
The effectors can be glands or muscles
Negative feedback mechanisms
This is where the control centre is wanting to reverse the change in the controlled condition
Baroreceptor
In the aortic arch and carotid sinus – are sensitive to stretch or pressure on the arterial system
Chemoreceptor -
glucoreceptor
Receptors that are sensitive to a change in the glucose within the
blood
Osmoreceptor
An osmoreceptor is a sensory receptor primarily found in the
hypothalamus of most homeothermic organisms that detects
changes in osmotic pressure - are sensitive to a change in osmolarity
– the amount of fluid present within the blood
Thermoreceptor
In the skin, sensitive to a change in body temperature
Control centre
is typically the hypothalamus in the brain
Baroreceptor to Vasomotor centre in the brain stem to Heart muscle, blood vessels
Chemoreceptor to pancreas to liver
Osmoreceptors in hypothalamus To Pituitary gland in brain to kidneys
Thermoreceptors in the skin to hypothalamus To Muscles, glands, blood vessels
Positive feedback mechanisms
This is where the change in the controlled condition is increased or intensified until the end result is reached and the feedback loop is terminated.
A positive feedback loop results in a change in the body’s status, rather than a return to homeostasis.
