A+P Exam 2: Ch 17, 18, 19

from Deb's study guide

common goal of the nervous and endocrine systems

common goal of the nervous and endocrine systems

to preserve homeostasis by coordinating and regulating the activities of other cells, tissues, organs and systems

direct communication

via gap junctions; uses ions, small solutes, and other lipid-soluble materials as chemical messengers; effects limited to adjacent cells of same type (example: cardiac muscle)

paracrine communication

via extracellular fluids; use paracrine factors as chemical messengers; effects limited to local area of high paracrine factor concentrations and target cells must have appropriate receptors

endocrine communication

via the bloodstream; uses hormones as chemical messengers; effects on target cells located in other tissues or organs; target cells must have appropriate receptors

neural communication

via synaptic clefts; use neurotransmitters as chemical messengers; effects limited to very specific areas; target cells must have appropriate receptors

hormones

chemical messengers released by endocrine cells/glands into the bloodstream to be transported throughout the body; regulate metabolic functions and activities of other cells in the body (their target cells)

amine hormones

hormones derived from a single amino acid; T3, T4, epinephrine, norepinephrine, dopamine, melatonin

peptide hormones

chains of amino acids; includes polypeptides (ADH, OXT) and proteins (insulin, HGH, and prolactin)

lipid derivatives

made from lipids; steroid hormones are built from cholesterol molecules and include testosterone, estrogen, progesterone, cortisone

lipid-soluble hormones

directly initiates the production of proteins within the target cell; easily diffuse through the cell membrane, binds to receptor in cytosol or in nucleus, forms receptor-hormone complex that enters the nucleus and binds to target gene on DNA

water soluble hormones

cannot diffuse through the cell membrane; must bind to a surface cell-membrane receptor; initiates a cell-signaling pathway within the cell (2nd messenger pathway), hormone signal eventually reaches target genes in DNA of the nucleus

antagonistic effects

one hormone inhibits response of another, they generate opposite responses (insulin and glucagon)

synergistic effects

two hormones with similar effects produce an amplified response (both FSH and estrogen required for maturation of the egg)

permissive effects

one hormone needed to activate another (renin stimulates conversion of angiotensin I to II)

negative feedback systems

physiological response causes a decrease in the release of the hormone; most commonly used

positive feedback systems

physiological response causes and increase in the release of the hormone; rarely used; ex. oxytocin release during labor

hypothalamus function

integrates activities of the nervous system and endocrine system

hypothalamus (hormones)

antidiuretic hormone and oxytocin; travels down infundibulum to the pituitary gland, stored in posterior lobe of pituitary

regulatory hormones control secretions of the anterior pituitary (releasing hormones and inhibiting hormones) travel in capillaries called hypophyseal portal system

pituitary gland

also known as “master gland”; divided into anterior and posterior lobes

posterior pituitary

posterior lobe of the pituitary gland, connected to the hypthalamus via the infundibulum; stores and secretes hormones synthesize by the hypothalamus (ADH and OXT)

antidiuretic hormone (ADH)

increases water reabsorption into the body from the kidney; results in a decrease in water loss from urine

oxytocin (OXT)

stimulates smooth muscle contractions of the uterus- stimulates childbirth; stimulates ejection of milk after delivery; known as the “cuddle hormone” as it surges during arousal and orgasm in both sexes

anterior pituitary

anterior lobe of the pituitary gland connected to the hypothalamus by the hypophyseal portal system; (thyroid stimulating hormone, adrenocorticotropic hormone, follicle stimulating hormone, luteinizing hormone, growth hormone, prolactin, melanocyte stimulating hormone)

thyroid stimulating hormone (TSH)

targets the thyroid gland; stimulates the thyroid to grow and increase its secretion of the thyroid hormones T3 and T4; released in response to thyrotropin-releasing hormone (TRH) from the hypothalamusa

adrenocorticotropic hormone (ACTH)

stimualttes the release of steroid hormones by the adrenal cortex

follicle stimulating hormone (FSH)

promotes egg production in females; promotes maturation of sperm in males

luteinizing hormone (LH)

induces ovulation in females and promotes secretion of estorgen and progesterone; stimulates production of sex hormones like testosterone in males

growth hormone (GH)

stimulates cell growth and reproduction by accelerating the rate of protein synthesis particularly in skeletal muscle and bone

prolactin (PRL)

stimulates mammary gland development and the production of milk during pregnancy and during nursing

melanocytes stimulating hormone (MSH)

stimulates melanocytes of the skin to increase their production of melanin

thyroid gland

located in neck below the larynx, anterior to trachea; regulated by TSH from the pituitary gland

thyroid follicles

hollow spheres lined by a simple cuboidal epithelium called follicle cells

viscous colloid

fluid containing a large quantity of dissolved proteins, cavity containing this fluid is surrounded by follicle cells of the thyroid

thyroglobulin

globular protein synthesized by follicle cells; secrete it into the colloid of the thyroid follicle

functions of T3 and T4

stimulates red blood cell production and enhanced oxygen delivery, stimulates activity of other endocrine tissues, accelerate turnover of minerals in bone, elevates rates of oxygen consumption and energy consumption in cells, increases HR and BP, increases sensitivity to sympathetic stimulation, maintains the normal sensitivity of respiratory centers to changes in oxygen and CO2 concentrations in the blood

c (clear cells)

produce calcitonin (CT), that lowers blood calcium levels when they are too high; works by increasing the deposition of calcium in bone by stimulating osteoblast activity

parathyroid gland

3 or 4 small glands embedded in posterior surfaces of the thyroid gland; composed of chief cells that produced parathyroid hormone (PTH)

parathyroid hormone (PTH)

increases blood calcium levels when they are too low; activates osteoclasts causing calcium to be freed from bone and released into the blood

adrenal gland

located superior to the kindey; adrenal cortex (outer) and adrenal medulla (inner)

adrenal cortex

produces steroid hormones from cholesterol and is divided into three regions; produces aldosterone, cortisol, cortisone, testosterone

adrenal medulla

releases hormones when the body is under stress and consists of hormone-producing cells; epinephrine and norepinephrine

epinephrine

(adrenaline); elevates blood sugar, regulates body during stress or anger; raises blood pressure, heartbeat, glycogen breakdown and increases all other sympathetic effects on the nervous system

norepinephrine

acts as a synergist to epinephrine (works with it to produce an amplified response)