Endocrine Flashcards
Know functions of the endocrine system
The endocrine system functions;
-Regulate homeostasis
-growth and development
-Reproduction
-Circadian rhythms
Know functions in the body that need to be regulated. Know the normal levels in the body.
-Fasting blood glucose levels 70-99 mg/dL
-blood pressure 110/170mm Hg
-blood serum electrolytes
-Resting heart rate 60-100 bpm
-blood pH 7.35 to 7.45
-Blood oxygen levels 95-100%
-Temperature 98.6F
Define negative and positive feedback cycles.
A negative feedback cycle is when the accumulation of the end product of a process inhibits the process and it will reverse to bring back homeostasis
Positive feedback is when the accumulation of the end product speeds up its own production and causes a cascade effect.
Know endocrine and nervous system controls and the differences between them.
The nervous system and the endocrine system act together to coordinate the systems of the body but the nervous system uses neurotransmitters and the endocrine system uses hormones.
Be able to list the major endocrine organs and describe their body locations.
Pituitary, hypothalamus, adrenals, pancreas, ovaries, testes, pineal, thyroid, parathyroid, thymus.
Describe exocrine glands.
Exocrine glands secrete their products into ducts, they do not secrete hormones.
Exocrine glands include,
-sudoriferous (sweat) glands
-breast milk
-saliva
-sebaceous (oil) glands
-mucous glands
-digestive glands
Be able to explain hormone activity to include up and down regulation.
Hormones are chemical mediator messengers, tiny amounts of them have huge effects.
Up regulation occurs when target cells produce more receptors in response to rising blood levels of hormones.
Down regulation; Target cells decrease the amount of receptors because they are desensitized to the high hormone concentration.
Know the difference between hormones, paracrines and autocrines
Hormone are chemical mediator messengers that act on a target cell and circulate the blood stream
Autocrines act on the same cell that secrete them
Paracrines do not circulate
Be able to describe lipid and water based hormones, their properties, and how they enter and affect the cell.
Lipid soluble hormones circulate bound to transport proteins. These bind to receptors within target cells and are synthesized by cholesterol. They are small and pass directly through target cell membrane from the hormone-receptor complex. They move into the nucleus where they either promote (gene activation) or retard (gene inhibition)
Water soluble hormones circulate freely in the plasma and bind to receptor but cannot enter the target cell so they bind with receptor protein in cell membrane. This activates an enzyme that produces cAMP (“second messenger”) which activates enzymes in the cell needed for the desired reactions.
Be able to list the three ways to regulate hormone release.
- Humoral control is based on blood levels of ions and nutrients
- Neural control through ANS using epinephrine and NOR
- Hormonal control release of a hormone in response to another hormone
Explain how a target cell responds to a hormone.
Target cell response depends on the hormone and the target cell. Responses may be
-synthesis of new molecule
-change in permeability of the cell membrane
-stimulating transport of a substance into or out of the cell
-altering the rate of metabolic actions
-activating or deactivating enzymes
-inducing secretions of another gland
-causing contraction of smooth or cardia muscle
It will have more or less receptors based on blood concentration
Explain the responses of a hormone based on the target cell.
A hormone alters cell activity and decreases or increases normal process of the cell
Know how hormones are inactivated.
Hormones are inactivated when they are removed by the kidneys and liver excreted in urine and feces
Know the hormones produced, gland of origin, target tissues, and actions for the hypothalamus, anterior and posterior pituitary, thyroid, adrenal medulla, and adrenal cortex.
Hypothalamus: no target tissue because it is all stimulating and inhibiting for the adenohypophysis
-Corticotropin-releasing hormone (CRH); stimulates release of ACTH at the adenohypophysis
-Gonadotropin-releasing hormone (GnRH); Stimulates release of FSH and LH at the adenohypophysis
-Growth hormone-releasing hormone (GHRH); stimulates release of GH at the adenohypophysis
-Growth hormone-inhibiting hormone (GHIH) or somatostatin; inhibits release of GH at adenohypophysis
-Prolactin-inhibition hormone (PIH); inhibits the release of PRL by by the adenohypophysis
-Prolactin-releasing hormone (PRH); stimulates release of PRL by the adenohypophysis
-Thyrotropin-releasing hormone (TRH); stimulates release of TSH at the adenohypophysis
Anterior Pituitary (adenohypophysis): (target tissues in parenthesis)
-human growth hormone (cartilage, bone, skeletal muscle, liver, and other body tissues); stimulates secretion of hormones that stimulate body growth and metabolism
-Thyroid stimulating hormone (thyroid gland) stimulates growth of thyroid land and secretion of its hormones
-Follicle stimulating hormone (testes, ovaries); stimulates sperm production. Stimulates oocyte production and estrogen secretion
-Luteinizing hormone (testes, ovaries); stimulates secretion of testosterone. Triggers ovulation and stimulates secretion of estrogen and progesterone.
-Prolactin (mammary glands); stimulates production and secretion of milk
-Adrenocorticotropic Hormone (adrenal cortex); stimulates secretion of hormones by adrenal cortex
-Melanocyte stimulating hormone (skin); Darkens skin pigmentation
Posterior Pituitary (neurohypophysis); (targe tissues in parenthesis)
-Anti-diuretic hormone (kidneys); Decreases water lost in urine by returning water to the blood
-Oxytocin (uterus and mammary glands); stimulates uterine contractions and milk ejection during suckling
Thyroid Gland; (target tissues in parenthesis);
-Thyroxin and Triiodothyronine (most body cells); increases metabolism and basal metabolic rate (BMR)
-Calcitonin (osteoclast cells in bones); decreases blood calcium levels by inhibiting osteoclasts
Parathyroid glands; (target tissues in parenthesis);
-Parathyroid hormone (osteoclast cells in bones); increases blood calcium levels by stimulating osteoclasts to break down bone matrix.
Adrenal cortex (target tissues in parenthesis;
-Aldosterone (Kidneys); decreases sodium and water loss in urine by returning sodium and water to the blood
-Cortisol (liver, muscle, and cells involved in body defenses); increases resistance to stress, increases blood glucose levels, and decreases inflammation
-Androgen (Uterus, mammary glands, and other body cells involved in secondary sex characteristics); insignificant in males; increases sex drive in females
Adrenal medulla (target cells in parenthesis);
-epinephrine and NOR (body cells involved in fight-or-flight response); promotes fight-or-flight response
Pancreas (target cells in parenthesis);
-insulin (most body cells); decreases blood glucose levels by transporting glucose into body cells
-glucagon (Liver); increases blood glucose levels by stimulating liver to break down glycogen into glucose
Ovaries (target cells in parenthesis)
-Estrogen and Progesterone (uterus, mammary glands, and other body cells involved in female sexual characteristics); stimulates development of female sex characteristics; helps regulate menstrual cycle.
Testes (target cells in parenthesis)
-Testosterone (testes, muscle, and other body cells involved in male sexual characteristics); Stimulates development of male sex characteristics; stimulates male sex drive; regulates sperm production
Pineal Gland (target cells in parenthesis)
-Melatonin (brain); Helps to set biological clock
Thymus
-Thymosin (T cells (type of white blood cell involved in immune response)); promotes maturation of T cells for the immune response
