Endocrine control of Growth Ch.23 Flashcards
where is the adrenal gland?
It sits on top of the kidney
what does the adrenal gland secrete?
It secretes neurohormones and classic hormones
the medulla cortex
the medulla cortex takes up the inner 1/4 of the gland its made up of modified sympathetic ganglia, it secretes mostly epinephrine
the adrenal cortex
the adrenal cortex takes up the outer 3/4 of the gland and secretes steroid hormones
what are the three zones of the cortex?
inner: zona glomerulosa
middle: zona fasciculata
outer: zona reticularis
what layer is zona glomerulosa and what does it secrete?
inner, ONLY aldosterone
what layer is zona fasciculata and what does it secrete?
middle, mostly androgens which are hormones dominant in men
what layer is zona reticularis and what does it secrete?
outer, mostly glucocorticoids main one is cortisol
what is cortisol?
It is essential for stress management
how does cortisol effect inflammation ?
cortisol inhibits inflammatory response by decreasing the movement of white blood cells (leukocytes) to sites of inflammation. causing the inflammatory response to decrease.
what is the control pathway for cortisol secretion?
HPA (hypothalamus-pituitary-adrenal)
the pathway begins at the hypothalamus with corticotropin realeasing hormone (CRH) this then goes to the hypothalamic-hypophyseal portal system then it goes the anterior pituitary gland which stimulates adrenocorticotropin hormone (ACTH)
this acts on the adrenal cortex which stimulates the release and synthesis of cortisol
what is cortisols effect on the immune system?
Cortisol suppresses the immune system through various pathways, which can be beneficial in reducing inflammation but may also increase susceptibility to infections
What is cortisols effect on the liver?
Cortisol promotes the production of glucose in the liver, increasing blood glucose levels.
Glycogen Storage: Some glucose is stored as glycogen in the liver.
What is cortisols effect on muscle tissue?
Cortisol breaks down proteins in skeletal muscles to provide substrates for gluconeogenesis.
what is cortisols effect on adipose tissue?
Lipolysis: It enhances the breakdown of fats, making fatty acids available for energy and glycerol for gluconeogenesis.
Hypercortisolism
An adrenal tumor that autonomously secretes cortisol = Primary hypercortisolism
A pituitary tumor that oversecretes ACTH
Secondary hypercortisolism
Cushing’s disease
Iatrogenic (physician-caused) hypercortisolism
Cushing’s syndrome
Hypocortisolism
Addison’s disease - hyposecretion of all adrenal steroid hormones
Thyroid hormones
It effects long term metabolism
It is not essential to life but essential for development and growth in children and infants
What two cell types make up thyroid?
Follicular and calcitonin cells
what do the follicular cells do in thyroid gland?
synthesis of thyroid hormones happens in follicles. they are spherical structures that are single layers of epithelial tissue and have a hollow center that is filled with glycoprotein mixture called colloid.
what is the purpose of iodine in the thyroid gland?
Without iodine TSH builds up because iodine plays a major role in the synthesis of thyroid hormones.
hypothyroidism
caused by lack of iodine in diet
slow reflexes, slow speech etc.
slow metabolism
slow heart rate
hyperthyroidism
over production of tsh
increased protein catabolism (weakness)
what is growth hormone for?
Protein Synthesis: Promotes protein synthesis, particularly in skeletal muscle.
Metabolic Effects: Causes lipolysis, decreases glucose uptake by muscles, and stimulates gluconeogenesis in the liver, increasing blood glucose levels.
Bone and Cartilage Growth: Works with insulin-like growth factors (IGFs) to stimulate bone growth and cartilage synthesis.
