Biology 30-1 - Hormones

Hypothalamus

• Homeostasis monitor

• Releasing hormone (RH → tropic)

Pituitary

Master gland

Posterior Pituitary

• ADH: H2O reabsorption in kidneys

• Stimulus: dehydration

• Hyposecretion: Diabetes insipidus

Anterior pituitary

• TSH

• ACTH

• HGH

TSH

• Stimulates thyroxine

• Tropic hormone

ACTH

• Stimulates aldosterone / cortisol

• Tropic hormone

HGH

• Stimulus: puberty (need to grow)

• Hyposecretion: pituitary dwarfism

• Hypersecretion (childhood): gigantism

• Hypersecretion (adult): acromegly

Thyroxine

• Metabolism

• Hypersecretion: Grave’s Disease

• No iodine = no thyroxine

  • TSH increases → Goitre

Calcitonin

• Lowers blood calcium

• Calcium into bones

Thyroid

• Thyroxine

• Calcitonin

Parathyroid

• PTH: raises blood calcium

• Calcium releases from bones

Pancreas

• Insulin (beta cells): lowers blood glucose after meal

  • Glucose to glycogen, excessive glucose to fat, increased cell permeability

  • Hyposecretion: diabetes mellitus

• Glucagon (alpha cells): raises blood glucose after fasting (opposite of insulin)

Adrenal glands

• Adrenal medulla (middle)

  • Epinephrine and norepinephrine

• Adrenal cortex

  • Cortisol and Aldosterone

Epinephrine and norepinephrine

• Regulates body’s short-term response to stress

• Response is rapid bc of nervous system

• Sympathetic (fight or flight)