Endocrine system Flashcards
Endocrine system: Components
- Hypothalamus
- Pituitary gland
- Thyroid gland
- Parathyroid glands
- Thymus gland
- Adrenal glands
- Pancreas
- Ovaries
- Testes
Endocrine system: Function
- Shares with the nervous system responsibility of maintaining homeostasis
- Regulates body activities through hormones secreted by glands and transported by blood to target cells
Hypothalamus: Components
- Hypothalamus
- Infundibulum
- Pituitary gland: Posterior lobe and Anterior lobe
Hypothalamus: Functions
- Controls body temperature, thirst, and hunger
- Regulates sexual behavior, and defensive reactions, circadian rhythms and states of consciousness
- Synthesizes hormones that stimulate of inhibit the secretion of pituitary hormones.
- Synthesizes oxytocin and antidiuretic hormones that are stores and released in the pituitary gland
Pituitary gland: Components
- Hypothalamus
- Capillaries of hypophyseal veins and arteries
- Posterior pituitary (lobe)
- Anterior pituitary (lobe)
Pituitary gland: Anterior Lobe functions
Synthesizes and secretes:
1. Human growth hormone (hGH) that stimulates nearly all body cells for growth and metabolism
2. Thyroid-stimulating hormone (TSH) that stimulates the thyroid gland
3. Follicle-stimulating hormone (FSH) that stimulates productions of sperm, oocytes, and estrogen
4. Luteinizing hormone (LH) that stimulates production of estrogen, progesterone, testosterone, and triggers ovulation
5. Prolactin (PRL) that promotes milk secretion
6. Adrenocorticotropic hormone (ACTH) that stimulates the adrenal cortex
7. Melanocyte-stimulating hormone (MSH) that produces darkened skin pigmentation
Pituitary gland: Posterior lobe
Stores and releases:
1. Oxytocin (OT) that stimulates contraction of smooth muscle cells during childbirth and milk ejection
2. Antidiuretic hormone (ADH) that stimulates the conservation of body water and raises blood pressure by constricting arterioles
Thyroid gland: Components
- Thyroid gland
- Common carotid arteries
- Trachea
- Larynx
- Follicular cells
- Parafollicular cells
Thyroid gland: Functions
- Follicular cells secrete thyroid hormones, T3 and T4, which regulate oxygen use and metabolic rate, cellular metabolism, and growth and development
- Parafollicular cells secrete calcitonin, which lowers blood calcium level
Parathyroid gland: Components
- Parathyroid glands
- Thyroid gland
- Common carotid arteries
Parathyroid gland: Functions
- Produces parathyroid hormone (PTH) which increases blood calcium and magnesium levels and decreases blood phosphate levels
- Increases rate of dietary calcium and magnesium absorption
- Increases bone resorption by osteoclasts
- Increases reabsorption and phosphate excretion by kidneys, promotes formation of horome calcitriol in kidneys
Thymus gland: Components
- Common carotid arteries
- Trachea
- Brachiocephalic veins
- Thyroid gland
- Thymus gland
- Right lung
- Left lung
Thymus gland: Function
- Produces the hormones thymosin, thymic humoral factor (THF), thymic factor (TF), and thymopoietin which promote the proliferation and maturation of T cells of the immune system
Adrenal Glands: Components
- Right adrenal gland
- Left adrenal gland
- Right renal artery
- Right renal vein
- Inferior vena cava
- Abdominal aorta
- Kidneys
- Adrenal cortex
- Adrenal medulla
Adrenal glands: Functions
- Adrenal cortex produces mineralocorticods (aldosterone) which increase levels of sodium and water and decrease levels of potassium in blood
- Adrenal cortex produces glucocorticods (cortisol) which (a) increase protein breakdown in muscle fibers; (b) promote glucose formation in the liver, (c) provide resistance to stress, depress immune responses; (d) stimulate anti-inflammatory effects
- Adrenal cortez produces androgens which are a source of estrogens after menopause in females
- Adrenal medulla produces epinephrine (adrenaline) and norepinephrine that contribute to the fight-or-flight response; help in resisting stress; Increase blood pressure; Increase blood flow to the heart, liver, and skeletal muscles; Dilates airways to the lungs; Increases blood levels of glucose
