Homeostasis Flashcards
Homeostasis
The tendency of the body to seek/maintain a condition of balance/equilibrium within its internal environment, even when faced with external changes
What 3 Systems Does it Effect?
Nervous System - vasodilation, vasoconstriction, shivering, sweating Endocrine - adrenaline, cortisol, thyroxine Behavioural - clothes change
What Happens when Fluids are too High?
- Osmoreceptors send signal to hypothalamus
- Hypothalamus tells pituitary gland to release less ADH
- Less ADH means kidney (effector) so less urine output
Baroreceptor
sensory neurones detecting pressure changes found in the blood vessels
Definition of Blood Pressure
The Force exerted as it presses against the walls of the blood vessels
Oncotic Pressure
the pulling force which draws fluid into the capillaries from surrounding tissue
Hydrostatic Pressure
the pushing force exerted on the walls of the capillaries out onto the surrounding tissue
Negative Feedback System
- Change detected by specialised receptors
- Receptor informs control centre
- Control centre sends signal to effector
- Effector Initiates response
- Response reinstates normal physiological range
Positive Feedback System
body continues to move away from optimum range, less common. Eg. Hormone production in birth
Temperature Regulation
- Thermoreceptors in skin, aorta, arteries detect change
- Signal sent to hypothalamus (control centre) in brain
- Hypothalamus sends signal to effectors
- Effector informs control centre when to stop
What Causes Temperature Change?
Conduction ie lying on cold concrete, convection ie jumping into sea, metabolic changes, environment
What Happens if Blood Sugar is too High?
beta cells detect ‘hyperglycaemia’ so pancreas releases insulin
What Happens if Blood Sugar is too Low?
Alpha cells detect ‘hypoglycaemia’ so pancreas releases glucagon
How Does Insulin and Glucagon Raise/Lower Blood Sugar Lvl’s?
Insulin converts glucose -> glycogen stored in the liver Glucagon is broken down to glucose for blood to cells
Hypoglycaemic Event
Blood Sugar >4mmol/L. Assess LOC. Glucogel = 40%. Glucose = 10%. IV, Glucagon1M, when alert make them eat carbs