Endocrine System: Hormones, Regulation, and Disease Patterns

What system uses hormones for long-term regulation?

Endocrine system

How do endocrine hormones travel?

Through the bloodstream

What determines whether a cell responds to a hormone?

Presence of the correct receptor

What is negative feedback?

Rising hormone levels inhibit further hormone release

Why is the hypothalamus neuroendocrine?

It receives neural input and releases hormones

What is the main job of the pituitary gland?

To release hormones that regulate other glands and tissues

How is the anterior pituitary regulated?

By blood via the hypothalamic-hypophyseal portal system

How is the posterior pituitary regulated?

By neurons

Which pituitary lobe produces hormones?

Anterior pituitary

Which pituitary lobe stores and releases hypothalamic hormones?

Posterior pituitary

What hormones are released by the posterior pituitary?

ADH and oxytocin

What are hydrophilic hormones?

Water-soluble hormones that bind membrane receptors

What are hydrophobic hormones?

Lipid-soluble hormones that bind intracellular receptors

Which hormone type acts faster?

Hydrophilic

Which hormone type has longer-lasting effects?

Hydrophobic

What is the thyroid hormone pathway?

TRH → TSH → T3/T4

What is the main effect of T3 and T4?

Increase metabolic rate and heat production

What symptoms occur with low T3/T4?

Weight gain, fatigue, cold intolerance

What hormone stimulates the thyroid gland?

TSH

What hormone lowers blood calcium?

Calcitonin

What hormone regulates sodium and potassium balance?

Aldosterone

What is the effect of aldosterone?

Sodium retention, potassium excretion, increased blood pressure

What hormone mediates long-term stress?

Cortisol

What are the effects of cortisol?

Increased blood glucose, muscle breakdown, stress response

What hormone stimulates cortisol release?

ACTH

What hormone lowers blood glucose?

Insulin

What hormone raises blood glucose?

Glucagon

Which pancreatic cells release insulin?

Beta cells

Which pancreatic cells release glucagon?

Alpha cells

What does ADH do?

Increases water reabsorption in the kidneys

What happens when ADH is low?

Large amounts of dilute urine and dehydration

What disease is caused by low ADH?

Diabetes insipidus

What hormone initiates puberty?

GnRH

What is the gonadal hormone pathway?

GnRH → FSH/LH → Sex hormones

What hormone is responsible for male secondary sex characteristics?

Testosterone

High TSH with low T3/T4 indicates what disorder?

Primary hypothyroidism (Hashimoto's)

High cortisol with low ACTH indicates what disorder?

Adrenal Cushing's syndrome

Low GnRH, FSH/LH, and testosterone indicates a problem where?

Hypothalamus

Low sodium, high potassium, low blood pressure suggests deficiency of what hormone?

Aldosterone

What stimulates ADH release?

Increased blood osmolarity

What inhibits ADH release?

Decreased blood osmolarity

What is the target tissue of ADH?

Kidneys

What is the effect of ADH?

Water reabsorption and increased blood volume

What stimulates oxytocin release?

Uterine stretching and infant suckling

What are the target tissues of oxytocin?

Uterus and mammary glands

What are the effects of oxytocin?

Uterine contractions and milk let-down

What stimulates TSH release?

TRH from the hypothalamus

What inhibits TSH release?

Increased thyroid hormones and somatostatin

What is the target of TSH?

Thyroid gland

What is the effect of TSH?

Growth of thyroid and synthesis of T3/T4

What stimulates ACTH release?

CRH from the hypothalamus

What inhibits ACTH release?

Increased cortisol

What is the target of ACTH?

Adrenal cortex

What is the effect of ACTH?

Release of adrenal corticosteroids

What stimulates prolactin release?

Prolactin-releasing hormone and suckling

What inhibits prolactin release?

Dopamine

What is the target of prolactin?

Mammary glands

What is the effect of prolactin?

Milk production

What stimulates LH and FSH release?

GnRH from the hypothalamus

What inhibits LH and FSH release?

Sex hormones (testosterone, estrogen, progesterone)

What are the targets of LH and FSH?

Male and female gonads

What is the effect of LH in males?

Testosterone production

What is the effect of LH in females?

Ovulation and progesterone production

What is the effect of FSH in males?

Sperm production

What is the effect of FSH in females?

Ovarian follicle maturation and estrogen production

What stimulates GH release?

GHRH, stress, exercise, fasting

What inhibits GH release?

Somatostatin

What are the target tissues of GH?

Liver, muscle, bone, adipose

What are the effects of GH?

Growth, protein synthesis, fat breakdown