Autonomic [Stress Response] Flashcards
Adrenal medulla hormones
Epinephrine and norepinephrine
Adrenal medulla stimulated by
ACh from sympathetic preganglionic neurons
Adrenal medulla principal actions
Enhance sympathetic autonomic alarm response
Adrenal cortex Mineralo-corticoids
Eg. Aldosterone stimulated by and principal actions
Increased K+ and angiotensin 2 in blood.
Increase blood Na+ and water and decrease blood K+ leading to increased blood vol and pressure
Adrenal cortex glucocorticoids (cortisol) stimulated by + principal actions
ACTH from pituitary which in turn is stimulated by CRH from hypothalamus.
Resistance reaction to stress, dampens inflammation and depresses immune responses
6 resistance reactions of glucocorticoids
Protein breakdown Gluconeogenesis Lipolysis Resistance to stress Vasoconstriction Anti-inflammatory Immune depression
Protein breakdown - glucocorticoids
Increase protein breakdown mainly in muscle fibres. Amino acids released into bloodstream may be used for synthesis of new proteins and ATP
Gluconeogensis - glucocorticoids
Liver cells convert some amino acids or lactic acid to glucose which neurons and other cells can use for ATP
Lipolysis - glucocorticoids
Breakdown of triglycerides and release of fatty acids from adipose tissue into the blood
Resistance to stress - glucocorticoids
Increased glucose and ATP combat stresses such as exercise, fasting, fright, etc.
Vasoconstriction - glucocorticoids
Blood vessels become more sensitive to hormones that cause vasoconstriction leading to raise in blood pressure
Anti-inflammatory - glucocorticoids
Inhibit WBC to participate in immune response to limit tissue damage by them. Unfortunately also retard tissue repair and slow wound healing
Immune depression - glucocorticoids
High _ conc depress immune responses. Used therapeutically following organ transplants to retard graft rejection
4 features of fight-or-flight response for stress response
Immediate burst
Sympathetic
Adrenal medulla involvements
Epinephrine and norepinephrine
Resistance reaction as stress response - 3 features
Slower, longer
Associated with hypothalamus - pituitary-adrenal cortex.
Corticosteroid production
What is the second stage of the stress response?
Reducing tissue damage (adrenal cortex)
Nerves, organ and effectors that CAUSE the alarm response
Sympathetic nerves, visceral effectors
organ and neurotransmitters that PROLONGS the alarm response
Adrenal medulla
Secretes NA/E
How does the hypothalamus control the pituitary gland?
Releases inhibitory hormones from axon termini which go to hypophyseal portal veins to secondary plexus then into pituitary cells
Hypothalamus releasing hormones to the adrenal glands pathway (??)
The hypothalamus releases CRH into the anterior pituitary, where ACTH is produced and this affects the adrenal glands.
Negative feedback effects on pituitary gland
Too much cortisol inhibits release of ACTH or CRH
4 steps to CAUSING resistance reaction
CRH released into primary hypophyseal plexus then portal vein to anterior pituitary. This releases ACTH into the bloodstream and the adrenal cortex secretes cortisol leading to the resistance reaction.
3 links between neuroendocrine and immune systems
Hormones, autonomic nerves and cytokines which point to the neuroendocrine
2 types of stress
Eustress, acute, GOOD
Distress
Posterior pituitary: how does it connect to the hypothalamus? How does it respond to neurons or hormones? What does it release?
Connects via hypothalamic-hypophyseal tract (neural)
Responds directly to neurons.
Releases oxytocin + ADH
Anterior pituitary: how does it connect to the hypothalamus? How does it respond to neurons or hormones? What does it release?
Via hypophyseal portal system (vascular).
Responds by releasing or inhibiting hormones from ventral hypothalamus.
Releases many hormones incl. ACTH
Name the 3 phases of the stress response in order and their key features and length
Alarm: ms, nerve
Alarm extension: S—>Min, nerve to hormone, medulla, NA/E.
Resistance: min—> hr, hormone, Cortex, cortisol
