Homeostatsis Flashcards
What is homeostasis
A state of balance between you cells, tissues, organs, organ systems
That your blood stays in a pH level range
That your blood glucose remains within a certain range
That you internal body temperature stays within a certain range
What does endotherm means
Warm blooded
Our body works hard to keep the internal temperature the same.
What is negative feed back
Is when some variable triggers a counteracting response. In order to come back to some set point
Negative feedback loop
Negative feed back in body temperature too hot
If you are too hot
Nerves which act as sensors tell the brain you too hot
Brain will send signal to counteract this heat
Sweat gland sweat, heat is lost as sweat evaporates off of your skin
You skin becomes red due to your blood vessels are getting wider
Helps lower the body temp
Negative feedback too cold
Too cold
You neurons tell your brain and brain the sends signs to stop sweating
You muscle contractions of shivering can generate heat
Blood vessels will now decrease to help conserve heat
Increasing you body temperature
Negative feed back in the regulation of your glucose
When blood glucose is too high
Hormone insulin is released
Insulin has the ability to make cells take in glucose
When glucoses is too low
Hormone glucagon is released
Cause the liver to release glucose into the blood
What is positive feedback
Is when instead of getting a counteracting response to some veritable you intensity the variable
When a baby is being born
Pressure is placed on the cervix
Causing it to contract
More release of hormones will equal more contractions and pressure which will cause more release of hormones
More hormones more contractions
Feedback systems can help us why
To see if there is a problem in the feedback system
For example type one diabetes
When the pancreas which is an organ that is involved in making some hormones like insulin is not working
Insulin is not produced
Your not going to be able to get glucose into you cells
You need to take the glucose in to be able to survive
Survival needs
Nutrition
Oxygen
Water
Maintenance of body temp
Maintenance of pressure
Homeostasis
The ability to maintain a relatively stable internal environment despite fluctuation in external environment
Examples of homeostasis
Blood sugar control
Blood levels of calcium, sodium etc
Body temperature
Blood pressure
PH of blood and other tissues
Negative feedback
The output of a system shuts off the original stimulus
So the mechanisms causes change in the opposite direction to the original change
Heat transfer
Heat is a form of energy, cannot be creators or destroyed, only transferred
Radiation
Convection
Conduction
Temperature is a quality, measured in Celsius
Control of body temperature
To cool down
Perspiration
Blood moves to periphery
Loose clothing
Movement of air
To warm up Blood moves away from periphery Shivering Piloerection Layers of clothing Increased activity
Core and peripheral temperatures
Core 37°
Blood sugar control
Blood sugar goes up
Detected by pancreas
Release of insulin
Sugar enters cell, glucose converted to glycogen in liver and muscles, and to adipose tissues
Positive feedback
The response enhances the original stimulus
Usual in health, as inherently unstable, is often a feature of disease
The change proceeds in the same direction as the original stimulus
Not appropriate way to regulate moment by moment
in health is used for one off or self limiting events
Blood clotting
Childbirth
Lactation
Lacking
Baby suckles at breast
Sensory receptors in the skin of the breast detect the sucking send impulses to hypothalamus
Hypothalamus signals posterior pituitary to release oxytocin
Oxytocin released in blood stimulates milk ejection from the breast
Positive feedback is often a feature of disease
Hypertension damage kidneys
Diseased kidneys lack blood flow
Kidneys cause systemic increases in blood pressure
Blood pressure rises
Or helpful feedback goes wrong
Platelets adhere to damaged vessels and other plaelets
Will stick to vessel wall damaged by disease
So material builds up inside blood vessel
Cannot break down fat enough and vessel blocked
