Homeostatic principles and thermoregulation Flashcards
What is adrenaline?
A hormone secreted by the adrenal glands under stressful conditions. It serves as a primary messenger, activating adenylyl cyclase
Describe the structure of the adrenal glands.
They’re located above the kidneys. They consist of cortex, medulla and blood vessels.
Where is adrenaline secreted from?
The adrenal medulla of the adrenal glands.
State five effects of adrenaline secretion on the body
-Increased breathing
-Increased heart rate
-Stimulates glycogen breakdown in the liver and muscles
-Stimulates pupil dilation
-Increases glycolysis in the muscles to produce ATP
What is tidal volume?
The volume of air we breathe in and out during each resting breath.
What is respiratory minute volume?
The volume of air we inhale or exhale from the lungs per minute.
How do you calculate pulmonary ventilation rate?
Tidal volume x breaths per minute. Those can be measured using a spirometer, device which records volume changes onto a graph as a person breathes.
What is negative feedback?
The product of a process that counteracts change to maintain equilibrium and minimize fluctuations. For example the homeostatic control of blood glucose levels.
What is positive feedback?
A process which causes an increase in change away from the normal levels. For example, initiation of a nerve impulse.
Define homeostasis
Maintaining a constant internal environment around an optimum despite external change.
What is the hypothalamus?
The region of the brain located near the pituitary gland that is involved in homeostatic control, including thermoregulation
How does the hypothalamus help to increase body t°?
-It stimulates vasoconstriction
-Stimulates contraction of hair erector muscles
-Stimulates psychological changes like increase in thermogenesis
-Stimulates rapid skeletal muscle contraction (shivering)
How does the hypothalamus help to decrease body t°?
-It stimulates vasodilation
-Stimulates the p0roduction and secretion of sweat
-Stimulates the relaxation of hair erector muscles to release any trapped air next to the skin
