Pituitary/HPA Axis Flashcards
How does the negative feedback system in the HPA
axis work?
When hormonal levels drops in plasma–>hypothalamus sends out releasing hormone–>signals pituitary–>sends out target stimulating hormone—>target gland releases hormone–> when serum level achieved, it shuts off
- works like an ac unit with a set temp- once it reaches target, it turns off
What is the role of hormones in the stress response?
- catecholamines and cortisol initiate the fight or flight response
What is considered to be the main stress hormone?
Cortisol
How does the HPA axis work?
Hypothalamus produces coritcotropin releasing hormone–>stimulates pituitary to release Adrenochorticotropic hormone–>stimulates adrenal gland to produce/release Cortisol
What are the lab findings of somebody with hypopituitsrism
Low levels of pituitary hormones and the hormones they regulate
Causes of hypopituitarism
Autoimmune (Sheehans syndrome)
Tumor
Infection
Trauma
Vascular problems (stroke)
Growth hormone deficiency in peds causes
-Proportional short stature dwarfism
- growth rate slow, <2”/yr
Growth hormone deficiency causes what in adults?
⬆️ body fat
⬇️ muscle mass
⬇️ bone mineral density
Anxiety, fatigue, lack of energy, poor thermoregulation
Excess growth hormone causes?
Giantism in peds(body parts proportional)
Acromegaly in adults (hypertrophic joints, wide forehead -Lurch from Adam’s Family)
Role of growth hormone
-Stimulates growth
-Impacts metabolism by fat breakdown, protein synthesis
-too much can contribute to insulin resistance
What hormones are produced by the posterior pituitary?
Oxytocin
Antidiuretic hormone(vasopressin)
What hormones are produced by the anterior pituitary?
-Growth hormone
-Thyroid stimulating hormone
-Adrenocorticotropic hormone
-Follicle Stimulating Hormone
-Luteinizing hormone
-Gonadotropin releasing hormone
-Prolactin
Differentiate between chronic stress and hormones that cause stress rxn?
Chronic stress = prolonged state of stress
hormones = chemical messengers that control the body’s reactions to stress, including the “fight-or-flight” response.
Luteinizing hormone does what
Triggers ovulation in females and testosterone production in males
Follicle stimulating hormone does what
Regulates development of eggs in females and sperm in males
Prolactin does what
Stimulates milk production in females
Adrenocorticotropic hormone does what
Stimulates the adrenal glance to release Cortisol
Thyroid stimulating hormones does what
Regulates production of thyroid hormones.
