pt 4: Adrenal gland structure Cortex (steroids) + medulla (catecholamines) Three adrenal cortex layers Zona glomerulosa, fasciculata, reticularis Zona glomerulosa Secretes aldosterone (mineralocorticoid) Aldosterone function Increases Na+ reabsorption, K+ excretion; raises blood pressure Aldosterone release triggered by Low BP, high K+, renin-angiotensin system, ACTH Renin-angiotensin system Low BP → renin → Ang I → Ang II → aldosterone + vasoconstriction Zona fasciculata Secretes cortisol (glucocorticoid) Cortisol function Increases glucose, suppresses immune system, maintains blood pressure High cortisol effects Immune suppression, muscle wasting, hyperglycemia Zona reticularis Secretes adrenal androgens Adrenal androgens Weak sex hormones contributing to puberty and libido Adrenal medulla hormones Epinephrine and norepinephrine Epinephrine effects Increases heart rate, metabolic rate Norepinephrine effects Increases vasoconstriction and blood pressure Pancreas function Exocrine (digestive enzymes) + endocrine (insulin, glucagon) Alpha cells in pancreas Produce glucagon Beta cells in pancreas Produce insulin Glucagon function Increases blood glucose via glycogenolysis and gluconeogenesis Insulin function Decreases blood glucose by increasing cellular uptake Somatostatin from pancreas Inhibits insulin and glucagon release Type 1 diabetes Autoimmune destruction of beta cells → no insulin Type 2 diabetes Insulin resistance; cells do not respond to insulin Effects of insulin Promotes glucose uptake, fat storage, glycogen formation Ovarian hormones Estrogen and progesterone Estrogen function Female development, menstrual cycle regulation Progesterone function Maintains uterus for pregnancy Testicular hormone Testosterone Testosterone functions Male traits, sperm production, libido Placental hormones hCG, estrogen, progesterone hCG function Maintains corpus luteum early in pregnancy Kidney hormone EPO (erythropoietin) EPO function Stimulates RBC production when oxygen is low Heart hormone ANP (atrial natriuretic peptide) ANP function Decreases blood pressure by reducing blood volume GI hormones Gastrin, secretin, CCK regulate digestion Skin hormone precursor Produces vitamin D precursor (cholecalciferol) Adipose hormone Leptin Leptin function Signals satiety and regulates metabolism Cushing’s syndrome Excess cortisol → moon face, buffalo hump, high glucose Addison’s disease Low cortisol/aldosterone → fatigue, low BP, hyperpigmentation Pheochromocytoma Adrenal medulla tumor causing excess epinephrine Conn’s syndrome Excess aldosterone → high BP, low K+ Hyperthyroidism symptoms Weight loss, heat intolerance, anxiety, fast heartbeat Hypothyroidism symptoms Fatigue, weight gain, cold intolerance Goiter Enlarged thyroid due to iodine deficiency or overstimulation Primary endocrine disorder Problem in the gland itself Secondary endocrine disorder Problem in pituitary or hypothalamus Calcitriol (active vitamin D) Increases Ca2+ absorption in intestines Endocrine disruptors Chemicals interfering with hormone actions

Adrenal gland structure

Cortex (steroids) + medulla (catecholamines)

Three adrenal cortex layers

Zona glomerulosa, fasciculata, reticularis

Zona glomerulosa

Secretes aldosterone (mineralocorticoid)

Aldosterone function

Increases Na+ reabsorption, K+ excretion; raises blood pressure

Aldosterone release triggered by

Low BP, high K+, renin-angiotensin system, ACTH

Renin-angiotensin system

Low BP → renin → Ang I → Ang II → aldosterone + vasoconstriction

Zona fasciculata

Secretes cortisol (glucocorticoid)

Cortisol function

Increases glucose, suppresses immune system, maintains blood pressure

High cortisol effects

Immune suppression, muscle wasting, hyperglycemia

Zona reticularis

Secretes adrenal androgens

Adrenal androgens

Weak sex hormones contributing to puberty and libido

Adrenal medulla hormones

Epinephrine and norepinephrine

Epinephrine effects

Increases heart rate, metabolic rate

Norepinephrine effects

Increases vasoconstriction and blood pressure

Pancreas function

Exocrine (digestive enzymes) + endocrine (insulin, glucagon)

Alpha cells in pancreas

Produce glucagon

Beta cells in pancreas

Produce insulin

Glucagon function

Increases blood glucose via glycogenolysis and gluconeogenesis

Insulin function

Decreases blood glucose by increasing cellular uptake

Somatostatin from pancreas

Inhibits insulin and glucagon release

Type 1 diabetes

Autoimmune destruction of beta cells → no insulin

Type 2 diabetes

Insulin resistance; cells do not respond to insulin

Effects of insulin

Promotes glucose uptake, fat storage, glycogen formation

Ovarian hormones

Estrogen and progesterone

Estrogen function

Female development, menstrual cycle regulation

Progesterone function

Maintains uterus for pregnancy

Testicular hormone

Testosterone

Testosterone functions

Male traits, sperm production, libido

Placental hormones

hCG, estrogen, progesterone

hCG function

Maintains corpus luteum early in pregnancy

Kidney hormone

EPO (erythropoietin)

EPO function

Stimulates RBC production when oxygen is low

Heart hormone

ANP (atrial natriuretic peptide)

ANP function

Decreases blood pressure by reducing blood volume

GI hormones

Gastrin, secretin, CCK regulate digestion

Skin hormone precursor

Produces vitamin D precursor (cholecalciferol)

Adipose hormone

Leptin

Leptin function

Signals satiety and regulates metabolism

Cushing’s syndrome

Excess cortisol → moon face, buffalo hump, high glucose

Addison’s disease

Low cortisol/aldosterone → fatigue, low BP, hyperpigmentation

Pheochromocytoma

Adrenal medulla tumor causing excess epinephrine

Conn’s syndrome

Excess aldosterone → high BP, low K+

Hyperthyroidism symptoms

Weight loss, heat intolerance, anxiety, fast heartbeat

Hypothyroidism symptoms

Fatigue, weight gain, cold intolerance

Goiter

Enlarged thyroid due to iodine deficiency or overstimulation

Primary endocrine disorder

Problem in the gland itself

Secondary endocrine disorder

Problem in pituitary or hypothalamus

Calcitriol (active vitamin D)

Increases Ca2+ absorption in intestines

Endocrine disruptors

Chemicals interfering with hormone actions