Hormonal Control

Anterior Pituitary (Master Gland)

• Produces many hormones

• Controls other endocrine glands

• Releases TSH, ACTH, FSH, LH

• Also releases GH, PRL, MSH

Lipid-Soluble (Steroid) Hormones – Effect on Cell

• Pass through cell membrane

• Enter the cell nucleus

• Turn genes on or off

• Cause protein synthesis

• Slow but long-lasting effect

• Examples: estrogen, testosterone

Negative Feedback

• Hormone controls its own release

• High hormone → less released

• Low hormone → more released

• Keeps body in balance

Hormone Characteristics

• Chemical messengers

• Released by endocrine glands

• Travel in the blood

• Act on specific target cells

• Effects are slow but long-lasting

Long-Term Stress Response

• Controlled by cortisol

• Increases blood glucose

• Breaks down proteins and fats

• Suppresses immune system

• Helps body cope with stress

Epinephrine (Adrenaline)

• Short-term stress hormone

• “Fight or flight”

• Increases heart rate

• Raises blood glucose

• Controlled by nervous system

Thyroxine (T₄) – Function

• Increases metabolic rate

• Causes cells to use more glucose

• Affects growth and development

Goitre – Causes

• Iodine deficiency

• Thyroid gland enlarges

• Thyroid hormones not produced properly

Parathyroid Hormone (PTH)

• Increases blood calcium

• Releases calcium from bones

• Increases calcium reabsorption in kidneys

• Turns on vitamin D for calcium absorption

Growth Hormone (GH) – Functions

• Stimulates bone growth

• Stimulates muscle growth

• Increases protein synthesis

• Increases fat metabolism

Aldosterone

• Acts on kidneys

• Increases sodium reabsorption

• Increases water retention

• Raises blood volume and pressure

Oxytocin

• Causes uterine contractions

• Causes milk release

• Example of positive feedback

• More contractions → more oxytocin

Type 1 Diabetes Mellitus

• Pancreas makes little or no insulin

• Blood glucose stays high

• Requires insulin injections

Cortisol

• Main glucocorticoid hormone

• Raises blood glucose

• Breaks down proteins and fats

• Anti-inflammatory

• Suppresses immune system

Insulin

• Lowers blood glucose

• Helps cells take in glucose

• Released after eating

• Produced by beta cells of pancreas

Testosterone

• Male sex hormone

• Produced by testes

• Causes male secondary sex characteristics

• Increases muscle development

• Deepens voice

Luteinizing Hormone (LH) – Male

• Acts on testes

• Stimulates testosterone production

Follicle Stimulating Hormone (FSH) – Female

• Stimulates egg development

• Helps ovaries produce estrogen

Pancreas

• Has endocrine and exocrine functions

• Endocrine part = Islets of Langerhans

• Produces insulin and glucagon

• Regulates blood glucose

Menstrual Cycle HormonesEstrogen

• Builds uterine lining

• Female secondary sex characteristics

• Egg maturation

Progesterone

• Maintains uterine lining

• Supports pregnancy

• Works with estrogen