Homeostasis & Hormones Flashcards
What are the 2 major elements in the internal environment and what do they do?
Interstitial fluid = leaves blood capillaries
Blood plasma = fluid surrounding blood cells
What needs to be regulated in homeostasis
Temperature
Glucose
PH
Blood pressure
Calcium Ions
Blood gases (O2, CO2)
Glucose homeostasis
Glucose is the most important simple sugars
All cells are able to metabolise glucose in order to produce energy
Hormones
Released by endocrine glands and travel in the blood to target cells
Produced by endocrine glands and diffuse capillaries, travels into bloodstream to target cells
Types of hormones
Steroid hormones - lipid soluble
Protein hormones
Insulin
Uptake of glucose from blood into cells
Conversion of glucose to glycogen for storage in liver and muscles
Use of glucose in cells to form ATP
Glucagon
Increased breakdown of glycogen stores to form glucose
Thermoregulation body temps increase/decrease
If body temps raise above 41 degrees then proteins in cells denature and fail to function
If body temps fall below 32 degrees metabolism slows and energy can’t be produced
What does amygdala identify?
Danger
What does hypothalamus activate?
Sympathetic NS
What does the adrenal medulla and adrenal cortex produce?
Medulla - adrenaline
Cortex - cortisol
Role of cortisol
Restore homeostasis after exposure to stress
Primary targets are metabolic and affects ion transport, immune response and memory
Metabolic effects include increased levels of glucose, fatty acids and amino acids in blood
2 processes in sleep
- Homeostasis - maintains balance between urge for sleep and wakefulness
- Circadian rhythm - directly related to time/length of sleep
REM and NREM
REM = dreaming, skeletal muscles paralysed
NREM = 4 stages of sleep
What hormone is secreted when it is dark and inhibited when it is light?
Melatonin
