Endocrine System Notes

Cell Communication

Consists of glands that secrete hormones.
Gland: organ that secretes chemicals, specifically hormones.
Hormone: chemical messenger secreted by a cell that travels through the blood to communicate with target cells.
A hormone can only trigger a reaction in specific cells, which are called target cells.
There are approximately 50 hormones in the human body.

Oxytocin stimulates the contraction of uterine muscles during childbirth.
Uterine muscle cells have receptors that bind oxytocin.
Oxytocin does not cause most other muscles in the body to contract because their cells lack the necessary receptors.

Metabolism: chemical reactions in the body.
Control of food intake and digestion: Hormones that give satiety and aid digestion/breakdown of food.
Tissue development.
Regulation of solute concentration of the blood (components of plasma).
Water balance in the body: increasing or decreasing urine volume.
Heart rate and blood pressure regulation.
Control of blood glucose and other nutrients.
Control of reproductive functions (LH / FSH).
Uterine contractions and milk release.
Immune system regulation.

Glands release hormones into the bloodstream.
Some glands have mixed/extra functions:
- Pancreas (enzymes).
- Ovaries (production of oocytes).
- Testis (production of sperm).

Pancreas cannot produce enough insulin, leading to increased glucose concentration in the blood.
Cause: Autoimmune (unknown).
Symptoms: Increased thirst, hunger, and fatigue.
Early onset: Usually diagnosed before age 20.
Less common.
Treatment: Daily insulin shots.
Recommended: Healthy diet and physical activity.

Pancreas makes insulin, but body cells do not take glucose in, resulting in increased blood sugar.
Causes: Genetics and lifestyle (lack of exercise, unhealthy diet).
Symptoms: Increased thirst, hunger, and fatigue.
Late onset: Usually diagnosed after age 40, but increasingly seen in children, teens, and young adults.
More common.
Treatment: Medication, healthy diet, and physical activity.

Too little growth hormone (HGH) is secreted by the anterior pituitary.
Causes: Genetic.
Signs: Small stature but normal body proportions.
Common complications: Bowing of the legs, hunching of the back, and crowded teeth.
Treatments are aimed at reducing complications.

Excess Growth Hormone is secreted by the anterior pituitary during childhood.
Symptoms: Excessive growth in height and internal organs.
Cause: Genetic or due to a very rare tumor causes the pituitary gland to release excess GH.
Treatment: Surgery or radiation to remove the tumor and regulate production of GH.
Early diagnosis is important.