- a gland whose secretion is drained by ducts onto the body surface or into a body cavity - ducted glands

- substances produced in one part of the body and transported to another part of the body where they affect chemical actions or the secretion of other hormones - chemical messenger

Endocrine glad Flashcards by Shelby Henderson

Endocrine gland

a ductless gland whose secretion is released directly into the bloodstrea,

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Exocrine gland

a gland whose secretion is drained by ducts onto the body surface or into a body cavity
ducted glands

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hormones

substances produced in one part of the body and transported to another part of the body where they affect chemical actions or the secretion of other hormones
chemical messenger

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describe the process of how hormones effect homeostasis

nerve impulses cause muscles to contract and glands to secrete
secretions effect the nervous system

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what are target cells?

target cells have receptors within their cell membranes that bind to a given hormone
hormones only effect specific target cells

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what are circulating hormones?

hormones that enter the bloodstream to reach distant target cells
may remain in the blood for a few hours
eventually inactivated by the liver and excreted by the kidneys

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what are local hormones?

hormones that do not enter the blood stream to reach target cells
inctivated QUICKLY by enzymes in interstitual fluid that surrounds cells

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what is paracrine? example?

local hormone acting on NEIGHBORING CELLS

- example: histamine

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what is autocrine? example?

local hormone acting on THE SAME CELL that secreted it

- example: interleukin-2

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what is the permissive effect?

the effect of one hormone on a target cell requires previous or simultaneous exposure to another hormone to enhance the target cell response or increase activity of another hormone

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what is the synergistic effect?

the sum effects of two or more hormones acting together is greater or more extensive than or each hormone acting alone

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what is the antagonistic effect?

the effect of one hormone on a target cell is opposed by another hormone

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what is a negative feedback system?

a corrective mechanism that opposes a variation from normal limits thus minimizing change
-maintain homeostasis

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what is humoral stimuli?

changing levels of ions and nutrients in the blood stream

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what is hormonal stimuli?

the release of other hormones

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what is neural stimuli?

signals from the nervous system

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what is considered to be the master endocrine gland?

-pituitary gland

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together the pituitary gland and the hypothalamus regulate…

practically all aspects of growth, development, metabolism, and homeostasis

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where is the hypothalamus located?

inferior to the two lobes of the thalamus

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where is the pituitary gland located?

sits in the sella turcica of the sphenoid bone

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what does the infundibulum connect?

-attaches the pituitary to the superiorly located hypothalamus

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what stimulates the release of hormones from the anterior lobe of the pituitary gland? what inhibits it?

stimulates: releasing hormone (RH) from the hypothalamus
Inhibits: inhibiting hormone (IH) from the hypothalamus

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what are the five types of cells in the anterior lobe of the pituitary gland?

somatotrophs
thyrotrophs
gonadotrophs
lactotrophs
corticotrophs

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what do somatotrophs produce and what do they do?

-produce HGH (human growth hormone) to stimulate body growth and regulate metabolism

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what do thyrotrophs secrete and what do they do?

-secrete thyroiod-stimulating hormone (TSH) which controls secretions and other activites of the thyroid gland

what do gonadotrophs produce?

- Follicle stimulating hormone (FSH) - Luteinizing hormone (LH) - stimulate secretion of estrogen and progesterone - maturation of oocytes and secretion of testosterone

what do lactotrophs produce?

-prolactin (PRL) to initiate the production of milk

what do corticotrophs produce?

- Adrenocorticotropic Hormone (ACTH): stimulates the cortex of the adrenal glands to secrete glucocorticoids - Melanocyte-stimulating hormone (MSH): affects skin pigment

which lobe of the pituitary gland produces hormones and which one stores and releases them?

- anterior produces | - posterior stores and releases it

what hormones does the posterior lobe of the pituitary gland store and release that are made by the hypothalamus?

- oxytocin (OT): contraction of the uterus and release milk - Antidiuretic Hormone (ADH): decreases water loss by the kidney -they are synthesized by nerosecretory cells in the hypothalamus

where is the thyroid gland located?

- lobes on either side of the trachea | - isthmus lies anterior to the trachea

The thyroid gland consists of what?

Thyroid follicles

What are the two types of cells thyroid follicles consist of?

- follicular cells: secrete T3and T4 | - parafollicular cells/c cells: produce calcitonin

What are "the" thyroid hormones?

T3 and T4

Does the thyroid gland store its secretory products?

Yep | -enough for 100 days

What are the functions of T3 (triiodothyronine) and T4 (thyroxine)?

- PRIMARY IMPORTANCE: increase basal metabolic rate to maintain normal body temperature - increase triglyceride breakdown and enhance cholesterol elimination in bile (lower cholesterol) - increase nervous tissue growth - lower calcium in blood

What are the parathyroid glands and where are they located?

- 2 pairs of small, oval shaped glands embedded in the posterior surface of the thyroid gland - a superior and inferior gland on each thyroid gland lobe

What are the two cells parathyroid glands consist of? What do they produce?

- principal/chief cells: produce parathyroid hormone (PTH to raise the level of calcium in blood - oxyphil cells: unknown function

What is the general structure of the adrenal glands?

- covering of connective tissue: capsule - adrenal cortex - innermost medulla

What are the three zones of the adrenal cortex?

- zona glomerulosa - zona fasciculata - zona reticularis

what does the zona glomerulus do?

control water and electrolyte balance

what does the zona fasciculata do?

- increase fat and protein breakdown - synthesize glucose - resistance to stress - anti inflammatory

what does the zona reticularis do?

produce male sex hormones in small amounts | -pretty insignificant

what cells does the adrenal medulla consist of? what do they do?

Chromaffin cells: secrete epi and norepi (catecholamines) for fight or flight response

where is the pineal gland located? what kind of cells does it contain and what do they secrete?

- inferior to the posterior portion of the brain's corpus callosum - Pinealocytes: secrete melatonin

what is melatonin?

- antioxidant protecting the CNS from free radical damage | - maintains circadian rhythms (day night cycle)

where is the pancreas located? what are the parts of the pancreas?

- across the posterior abdominal wall from the duodenum to the spleen, posterior to the stomach - head, neck, body, and tail

what is the difference between the exocrine and endocrine portion of the pancreas?

Exocrine: produce digestivev enzymes Endocrine: produce hormones to raise and lower blood glucose levels

what are the exocrine cells that produce digestive enzymes in the pancreas?

acini (acinar cells)

what endocrine tissue is scattered around the acini in the pancreas?

islets of langerhans

what are the 4 types of cells in each islet of langerhans?

1. alpha cells 2. Beta cells 3. Delta cells 4. F cells

what do alpha cells do?

produce glucagon to raise blood glucose levels

what do beta cells do?

produce insulin to lower blood glucose levels

what do delta cells do?

-inhibit growth hormone

what do F cells do?

-inhibit gallbladder contraction

Alpha and Beta cells controlling blood glucose levels are an example of what?

negative feedback system

what is the function of the ovaries?

- produce reproductive cell/ovum - produce estrogen: regulate development of female sex organs and sex characteristics - produce progesterone: prepares uterus for pregnancy

the ovaries and the testes are said to be

homologous

septa form a dense fibrous capsule that divides each testis into what?

lobules! each lobule contains seminiferous tubules that produce sperm

in addition to sperm, what do the testes produce? function?

testosterone! - responsible for normal growth and development of male reproductive organs - necessary for development and maintenance of secondary sex characteristics