The Endocrine System Flashcards
Hormones (3)
- are chemicals secreted into the bloodstream
- slow but signals are long lasting
- bond to the receptors on target cells
Endocrine glands
- are ductless glands that secrete hormones into the spaces between cells, and from those spaces these chemical messengers diffuse into the bloodstream
Exocrine glands
Ex. (4)
- have ducts and they excrete the substances that they produce
- ex salivary glands, sweat glands, sebaceous glands, and mammary glands
Hypersecretion
- the secretion of too much of one or more hormones
Hyposecretion
- the secretion of too little of one or more hormones
- Ex. Diabetes Mellitus
Pituitary Gland
- Is located within the brain, composed of endocrine and nervous tissue
Adernohypophysis is composed of ______ tissue
- endocrine tissue
Neurohypophysis
- portion composed of nervous tissue
Adrenocorticotropic hormone (ACTH)
- makes the adrenal cortex increase in size and excrete more cortisol.
Luteinizing hormone (LH)
- stimulates ovulation in females, stimulates testosterone production in the testes of males
Thyroid-stimulating hormone (TSH)
- stimulates the production of thyroid hormones
Growth hormone (GH) (hyper/hypo)
- stimulates the development of tissue proteins and the breakdown of fats
- Hypersecretion during development can cause the condition gigantism which involves the growth to a “gigantic” size
- Hyposecretion can lead to dwarfism, which involves the growth to a smaller-than-normal size
Follicle-stimulating hormone (FSH)
- promotes the development of ova in females and production of sperm in males
Prolactin (PRL)
- stimulates breast development and milk secretion
- Hyposecretion of ADH can cause diabetes insipidus, which involves an acutely-elevated production of urine
Oxytocin (OT)
- plays a role in social bonding, milk letdown, and labour
Hypothalamus
- Antidiuretic hormone (AHD) and Oxytocin (OT), are produced, and are released by the pituitary gland
Thyroid Gland (location and Hormones)
- located between the larynx and trachea
- produces 2 thyroid hormones; (Triiodothyronine and Thyroxine) and a third hormone called Calcitonin (CT)
Function of Thyroid Hormones (3)
- influence cellular metabolism; by speeding up the release of energy from nutrients
- for normal day-to-day function
- growth and development
Hyperthyroidism / Graves Disease
- too much energy released which results in being restless, nervous, irritable and weight loss
- an inherited autoimmune condition involving hyperthyroidism; It can result in bulging eyes
Hypothyroidism / Goiter
- inadequate availability of thyroid hormones
- an enlargement of the thyroid gland, as it attempts to increase its ability to secrete hormones.
- It’s due to an iodine deficiency
Cretinism
- a developmental condition affecting mental and sexual development due to hyposecretion of thyroid hormones early in life
Myxedeme
- decreased physical and mental capacity, weight gain, skin and hair changes - occur later in life
Calcitonin
- prevents the build-up of calcium in the blood
- prevents hypercalcemia - an excess of calcium in the blood
Parathyroid Glands Parathyroid Hormone (PTH)
- excrete parathyroid hormone (PTH)
- PTH increases blood calcium levels by promoting the breakdown of bone tissue
Adrenal Glands (location + structure)
- Sits atop the kidneys
- it’s divided into 2 discrete endocrine glands; the Adrenal Cortex and the Adrenal Medulla
Adrenal Cortex secretes what 3 hormones?
- mineralocorticoids
- glucocorticoids
- sex hormones
Mineralocorticoids
- the main mineralocorticoid is called aldosterone
- influences the sodium-potassium balance by promoting the reabsorption of sodium and excretion of potassium
Glucocorticoids
- The main glucocorticoid is cortisol
Sex Hormones
- secretes male hormones called androgens which is similar to testosterone
- In females, androgens influence the sex drive
Adrenal Medulla
- produces epinephrine (as a drug, it’s called adrenalin and norepinephrine (noradrenaline).
- they’re produced as part of our fight/flight response (increase blood pressure and glucose levels)
Pancreatic Islets
- are tiny glands (small clusters of cells) scattered about the pancreas
- produce Alpha and Beta cells
- Glucagon and insulin both play a role in maintaining blood glucose levels, but have opposite (that is, antagonistic) effects
Alpha Cells
- produce the hormone Glucagon
- Glucagon converts Glycogen, a substance stored in the liver, into glucose. This increases blood glucose levels
Beta Cells
- produce the hormone insulin
- Insulin moves blood glucose into cells, promoting its metabolism
Type 1 Diabetes
- pancreatic islets hyposecrete insulin so less blood glucose moves into the cells
- due to insufficient production of insulin
Type 2 Diabetes
- there is adequate insulin, but the receptors upon which the hormone acts are impaired
- due to target cell insensitivity to insulin.
Pineal Gland “Third Eye” / Melatonin
- its activity responds to sensory information related to cycles of light and dark
- Produces melatonin, for the importance of the regulation of sleep, influences menstruation and onset of puberty
Hyper/Hypo Melatonin
- Hyper = can make you feel groggy and cause difficulty waking up in the morning (seasonal affective disorder)
- Hypo = can be the root cause of some cases of insomnia
Antidiuretic Hormone (ADH)
- against the creation of urine, so it plays an important role in fluid balance
Cortisol
- influences blood glucose, blood pressure levels, and it has anti-inflammatory effect
Aldosterone
- affects the sodium-potassium balance
Insulin
- reduces blood glucose levels by moving glucose into cells
Hypercalcemia
- due to a build-up of calcium in the blood
