L28: Stress Response

• The targets and effects of cortisol are liver, muscle and adipose (fat mobilises fuel). pancreas - opposes insulin and stimulates glucagon), cardiovascular system and immune system.
• Adrenal gland location and hormones

  A) cortex

  B) medulla

  C) two adrenal glands

  D) each

  E) on top

  F) kidney

  G) cortisal

  H) secreted

  I) cortex

  J) outer

  K) aldosterone

  L) cortex

  M) outer

  N) catecholamines

  O) medulla

  P) middle

  Q) adrenal gland

  
• the adrenal gland anterior surfaces are covered by a layer of parietal perituneum and are richly supplied with blood vessels
• plasma cortisal concentration fluctuates in a 24-hr circadian rhythm.
• cortisol is the highest upon waking up from sleep. if normal sleep patterns are disturbed, it will affect the normal pattern of cortisol release
• target cell activation by cortisol

  cortisol is lipid-soluble and produced as required. it is carried in blood bound to a carrier protein and detaches from the carrier protein and enters the target cell
• in the target cell, the cortisol binds to a receptor in the cytosol. the cortisol-receptor complex enters the nucleus and binds to DNA. this activates specific genes to produce proteins having effects. the response time is minutes - days.
• the effects of target cell activation by cortisol is that it increases blood pressure by stimulating pancreas, liver, skeletal muscle and adipose.
• the effects of target cell activation by cortisol also maintains normal blood pressure and suppresses inflammation, which boosts overall immunity
• increasing blood pressure by stimulating pancreas to release glucagon.
• increasing blood pressure by stimulating liver is to reduce glucose intake from blood and create new glucose
• increasing blood pressure by stimulating skeletal muscle is to reduce glucose intake from blood and increase protein breakdown
• increasing blood pressure by stimulating adipose is to reduce glucose intake from blood and increase fat breakdown
• the adrenaline from adrenal medulla synthesises epinephrine and norepinephrine
• adrenal cortex is yellowish as stored lipids. it produces more than 2 dozen steroid hormones
• fuel mobilisation into blood plasma

  A) energy

  B) higher

  C) normal

  D) stress

  E) most hormones

  F) resistance phase

  G) increase fuel

  H) plasma

  I) fats

  J) amino

  K) acids

  L) mobilised

  M) non-neural

  N) use

  O) glucose

  P) mobilised

  Q) neural tissue

  
• Target cell activation

  A) corticotropin releasing hormone

  B) adrenocorticotropin

  C) cortisol

  D) reduce release

  
• Alarm phase (fight or flight). the sympathetic nerves stimulate catecholamine secretion
• sympathetic nerves stimulate the adrenal gland (medulla) to release adrenaline and noradrenaline into the main blood stream and to stimulate target cells to help the body deal with stress
• an immediate response to the stress occurs and is directed by autonomic nervous system
• target cell activation by catecholamines

  catecholamines are water-soluble and travel in blood unbound. they bind to the membrane receptors and initiate actions of a second messenger system
• target cell activation by catecholamines

  catecholamines lead to amplification if cellular responses that help the body deal with stress. the response time is seconds to minutes
• target cell activation by catecholamines

  A) hormone

  B) protein receptor

  C) G protein activated

  D) 2nd messenger pathway

  E) cellular

  
• catecholamine effects

  the increased intake of O2 and delivery of blood to cells in lungs, heart and blood vessel
• catecholamine effects

  the increased fuel released into the blood for cells to use increase liver (glycogen breakdown, making new glucose), skeletal muscle (glycogen breakdown) and adipose fat breakdown
• phases/ stages of stress response ' general adaptation syndrome'

  A) homeostasis

  B) alarm

  C) resistance

  D) exhaustion

  
• alarm phase fight or flight

  A) brain

  B) sympathetic stimulation

  C) adrenal medulla

  D) epinephrine and norepinephrine

  E) general sympatheic activation

  
• increased breathing rate means increased oxygen intake
• increased heart rate means increased oxygen and glucose circulated to the brain and skeletal muscle
• dry mouth means reduced activation of unnecessary body functions
• the stress response begins when distress signals are sent to the hypothalamus from an emotions centre of the brain.
• hypothalamic neurons are the control centre for both sympathetic and parasympathetic nervous systems
• stress triggers the hypothalamus to activate the sympathetic nervous system
• if the alarm stress is removed, the alarm phase ends, adrenaline release stops and the body enters a recovery stage.
• the recovery stage after alarm phase: glycogen stores in liver and muscle are replenished. the heart rate and blood pressure returns to normal. if the stress continues, the body enters the resistance phase
• resistance is the body working to resist the effects of stress
• resistance occurs when stress lasts longer than a few hours. the cortisol is the dominant hormone and other hormones play important roles adrenaline, growth, ADH, etc.
• thyroid hormones are involved in resistance phase
• energy demands in resistance phase remain higher than normal because of the combined effects of hormones
• the neural tissue in resistance phase is in high demand of energy